HK1090498A - Method and apparatus for wireless network hybrid positioning - Google Patents

Abstract

Methods and apparatuses for position determination and other operations. In one embodiment of the present invention, a mobile station uses wireless signals from a plurality of wireless networks (e.g., with different air interfaces and/or operated by different service providers) for position determination (e.g., for data communication, for obtaining time and/or frequency information, for range measurement, for sector or altitude estimation). In one embodiment of the present invention, mobile stations are used to harvest statistical data about wireless access points (e.g., the locations of mobile stations that have received signals from the wireless access points, such as from cellular base stations, wireless local area network access points, repeaters for positioning signals, or other wireless communication transmitters) and to derive location information (e.g., position and coverage area of the wireless access points) for the wireless networks from the collected statistical data.

Description

Method and apparatus for wireless network hybrid positioning

This application relates to and claims U.S. provisional patent application No. 60/483,094, filed on 27/6/2003.

Technical Field

The present invention relates to position determination systems, and more particularly, to hybrid positioning using wireless communication signals.

Background

To perform position location in a wireless cellular network (e.g., a cellular telephone network), methods are based on performing trilateration using timing information sent between each of a number of base stations and a mobile device, such as a cellular telephone. A method, referred to as Advanced Forward Link Trilateration (AFLT) in CDMA or Enhanced Observed Time Difference (EOTD) in GSM or observed time difference of arrival (OTDOA) in WCDMA, measures the relative time of arrival of signals transmitted from each of several base stations at a mobile device. These times are transmitted to a location server, such as a Position Determination Entity (PDE) in CDMA, which uses these times of reception to calculate the position of the mobile device. The transmission times at the base stations are adjusted so that, in a particular time case, the times of day (time-of-day) associated with the base stations are within a specified error bound. The exact location and time of reception of the base station is used to determine the location of the mobile device.

Fig. 1 shows an example of an AFLT system in which the time of reception of signals from cellular base stations 101, 103 and 105 (TR1, TR2 and TR3) is measured at a mobile cellular telephone 111. This timing data can then be used to calculate the position of the mobile device. Such calculations may be done at the mobile device itself, or at the location server if the timing information so obtained by the mobile device is transmitted to the location server via a communication link. Typically, the time of reception is communicated to the location server 115 through one of the cellular base stations (e.g., base stations 101, or 103, or 105). Location server 115 is coupled to receive data from base stations through mobile switching center 113. The location server may include a Base Station Almanac (BSA) server that provides the location of base stations and/or the coverage area of base stations. Alternatively, the location server and the BSA server may be separate from each other; and the location server communicates with the base station to obtain a base station almanac for position determination. The mobile switching center 113 provides signals (e.g., voice communications) to and from a landline Public Switched Telephone Network (PSTN) so that signals can be communicated to and from mobile telephones and to other telephones (e.g., landline telephones or other mobile telephones on the PSTN). In some cases, the location server may also communicate with a mobile switching center via a cellular link. The location server may also monitor transmissions from several base stations in an effort to determine the relative timing of these transmissions.

In another approach, known as uplink time of arrival (UTOA), the time of reception of a signal from a mobile device is measured at several base stations (e.g., measurements made at base stations 101, 103, and 105). If the arrows TR1, TR2 and TR3 are reversed, fig. 1 applies to this case. The timing data can then be communicated to a location server to calculate the location of the mobile device.

However, a third method of performing position location includes using circuitry in the mobile device for the united states Global Positioning Satellite (GPS) system or other Satellite Positioning Systems (SPS) or a combination of satellites and pseudolites, such as the russian GLONASS system and the proposed European galileo system (European GalileoSystem). Pseudolites are ground-based transmitters that broadcast a PN code (similar to a GPS signal) modulated on an L-band carrier signal, generally synchronized with SPS time. Each transmitter may be assigned a unique PN code to allow mobile device identification. Pseudolites are useful in situations where SPS signals from orbiting satellites may be difficult to obtain, such as tunnels, mines, buildings, or other enclosed areas. The term "satellite" as used herein is intended to include pseudolites or equivalents of pseudolites, and the term GPS signals as used herein is intended to include GPS-like signals from pseudolites or equivalents of pseudolites. The method of determining the position of a mobile station using an SPS receiver may be fully automatic (where the SPS receiver determines the position of the mobile station without any assistance), or may utilize the wireless network to provide assistance data or be shared in the position calculation. Examples of these methods are described in U.S. Pat. nos. 6,208,290, 5,841,396, 5,874,914, 5,945,944, and 5,812,087. For example, U.S. patent No. 5,945,944 describes, among other things, a method of obtaining accurate time information from cellular telephone transmission signals, which is used in conjunction with SPS signals to determine the position of a receiver; U.S. patent No. 5,874,914 describes, among other things, a method of determining the position of a mobile device by transmitting a doppler frequency offset of a satellite in view (in viewstellite) to a receiver on the mobile device over a communication link; U.S. patent No. 5,874,914 describes, among other things, a method of transmitting satellite almanac data (ephemeris data) to a receiver over a communication link to assist the receiver in determining its position; U.S. patent No. 5,874,914 also describes, among other things, a method of locking to a precision carrier frequency signal of a cellular telephone system to provide a reference signal at a receiver for SPS signal acquisition; U.S. patent No. 6,208,290 describes, among other things, a method of determining approximate Doppler (Doppler) using the approximate location of a receiver to reduce SPS signal processing time; and U.S. patent No. 5,812,087, among other things, describes a method of comparing different records of received satellite data information to determine the time at which one of the records was received at the receiver to determine the position of the receiver. In a practical low cost embodiment, both the mobile cellular communication receiver and the SPS receiver are integrated into the same housing, and may in fact share common electronic circuitry.

In another variation of the above method, the Round Trip Delay (RTD) of the signal sent from the base station to the mobile device and then back is found. In a similar (but alternative) approach, the round trip delay is found for signals sent from the mobile device to the base station and then back. Each of these round trip delays is divided by two to determine an estimate of the one-way propagation delay. Knowledge of the location of the base station, plus one-way delay, limits the location of the mobile device to a circle on the earth. Two such measurements from different base stations then result in two circular intersections, which in turn limits the position to two points on the earth. The third measurement (even angle of arrival or cell sector identification) solves the ambiguity problem (ambiguity).

The combination of AFLT or U-TDOA with an SPS system may be referred to as a "hybrid" system. For example, U.S. patent No. 5,999,124 describes, among other things, a hybrid system in which the location of a cell-based transceiver is determined by a combination of at least the following factors: 1) a time measurement representing a travel time of information in the cell-based communication signal between the cell-based transceiver and the communication system, 2) a time measurement representing a travel time of the SPS signal.

Altitude assistance (assistance) has been used in various ways to determine the position of a mobile device. Altitude assistance is typically based on a pseudo-measurement of altitude. Knowledge of the altitude of the position of the mobile device limits the possible positions of the mobile device to the surface of a sphere (or ellipsoid), the center of which is located at the center of the earth. This knowledge can be used to reduce the number of independent measurements required to determine the position of the mobile device. For example, U.S. patent No. 6,061,018 describes, among other things, a method in which an estimated altitude may be determined from information of an cellular object, which may be a cellular location having a cellular location (site) transmitter in communication with the mobile device.

Disclosure of Invention

Methods and apparatus for hybrid location determination and/or other types of operations with communication signals are described herein. Some embodiments of the invention are summarized in this section.

In one aspect of the invention, a mobile station uses wireless signals from a plurality of different wireless networks (e.g., having different air interfaces, core technologies, and/or operated by different service providers) for position determination (e.g., for data communications, for obtaining time and/or frequency information, for position measurement, for sector or altitude estimation). In certain other aspects of the invention, the mobile station is configured to harvest statistics about the wireless access points (e.g., the location of the mobile station that has received signals from the wireless access points, such as signals from cellular BASE stations, wireless local area network access points, personal area communications transmitters, repeaters or beacons for positioning signals, or other wireless communications transmitters) and to derive location information for the wireless network (e.g., the location and/or coverage area of the wireless transmitter, wireless transmitter identification information such as SID/NID/BASE-ID, MSC-ID, IP address, MAC address, logical name, etc.) from the gathered statistics. Note that in this application, the wireless transmitter is typically a ground-based transmitter as opposed to an orbiting satellite, which is a transmitter.

In one aspect of the invention, an exemplary method of operating a mobile station comprises: determining, at a mobile station, identification information of a first wireless transmitter of a first wireless network accessible by the mobile station, the first wireless transmitter being an access point; during position determination of the mobile station, identification information from the mobile station is communicated to a remote server via a second wireless transmitter of a second wireless network. In this exemplary method, the first wireless network is different from the second wireless network. The first and second wireless access points use different communication protocols, and/or air interfaces and/or architectures. For example, a first wireless access point is used to utilize a signal such as a) UWB (ultra wide bandwidth); or b) an access technology of one of the Wi-Fi (Wireless Fidelity) supported by the various IEEE802 standards (e.g., 802.11, 802.15, 802.16, 802.20) to access a Local Area Network (LAN) of the first wireless network; and the second wireless access point is a cellular base station for a wireless telephone system of a Wide Area Network (WAN), such as a system using one of: a) TDMA (time division multiple access); b) GSM (global system for mobile communications); c) CDMA (code division multiple access); d) W-CDMA (wideband code division multiple Access); e) TD-SCDMA (time division synchronous code division multiple access); f) cdma2000IX EV-DO (Evolution data only) or cdma2000IX EV-DV (Evolution data and voice); and g) other networks, such as: ANSI-41, GSM-MAP, IS-136, iDEN (Integrated digital enhanced network), GERAN, UTRAN, CDMA DS-MAP, CDMA MC-41, CDMA DS-41, CDMA MC-MAP, etc. The first service provider may operate a first wireless network and the second service provider may operate a second wireless network. The first wireless access point may support two-way communication. In one example of this method, a mobile station determines positioning information indicative of a distance between the mobile station and a first wireless access point; and the mobile station communicates the location information to the server through the second wireless access point to determine the location of the mobile station. The positioning information may include, for example, an indication of a signal level of a signal transmitted from the first wireless access point and received at the mobile station. Measurements of pseudoranges (pseudoranges) to SPS (satellite positioning system) satellites may be determined in an SPS receiver of the mobile station and may be communicated from the mobile station to a server through a second wireless access point to determine the position of the mobile station. In an example, after communicating the identification information of the first wireless access point to the server, a location of the first wireless access point is received from the server.

In another aspect of the present invention, a method of operating a mobile station includes: receiving, at a mobile station, a first signal transmitted from a first wireless access point of a first wireless network supporting two-way communication; determining a range measurement (e.g., a range measurement indicative of a range between a mobile station and a first wireless access point) using the first signal; communicating a second signal between the mobile station and a second wireless access point of a second wireless network different from the first wireless network; communicating between the mobile station and the server through a second wireless access point of a second wireless network to determine the location of the mobile station. In an example in accordance with this aspect, the first signal can be used to calibrate a local oscillator of the mobile station (e.g., lock the local oscillator to a carrier frequency signal in a first signal transmitted from a first wireless access point of the first wireless network). Also, accurate time information (e.g., timing markers or system time) can be obtained from the first signal. The second wireless access point may communicate with the mobile station according to a standard for wireless local area networks, or it may communicate with the mobile station according to a standard for wireless wide area networks. In an example, the first wireless access point is a base station (e.g., a cellular telephone "tower") of a wireless cellular telephone communication system.

The present invention includes methods and apparatus for performing these methods, including data processing systems that perform these methods, and computer readable media which when run on data processing systems cause the systems to perform these methods. Furthermore, the invention described herein may be implemented on different nodes within a system, including mobile stations, base stations (such as wireless access points) or location servers or other nodes in a network or wireless network.

Other features of the present invention will be apparent from the accompanying drawings and from the detailed description that follows.

Drawings

The present invention is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements.

Figure 1 shows an example of a prior art cellular network that determines the location of a mobile cellular device.

Figure 2 shows an example of a server that can be used in the present invention.

Fig. 3 shows a block diagram representation of a mobile station according to an embodiment of the invention.

FIG. 4 shows an example of a hybrid positioning system according to an embodiment of the invention.

FIG. 5 shows another example of a hybrid positioning system according to an embodiment of the invention.

Fig. 6 illustrates a method of determining the location of a wireless access point according to an embodiment of the invention.

Fig. 7 illustrates another method of determining location information for a wireless access point according to an embodiment of the invention.

Fig. 8 illustrates a hybrid location determination method using a plurality of wireless networks according to an embodiment of the present invention.

Fig. 9 illustrates a hybrid position determination method using two wireless networks for communication with a server according to an embodiment of the present invention.

Fig. 10 illustrates a method of generating location information regarding a wireless access point in accordance with an embodiment of the present invention.

Fig. 11 shows a hybrid position determination method using a wireless network for communication and another wireless network for measurement of positioning parameters according to an embodiment of the present invention.

Fig. 12 is a flowchart illustrating another exemplary embodiment of the present invention.

Fig. 13 is a flowchart illustrating another exemplary embodiment of the present invention.

Fig. 14 is a flowchart illustrating another exemplary embodiment of the present invention.

Detailed Description

The following description and drawings are illustrative of the invention and are not to be construed as limiting the invention. Numerous specific details are described to provide a thorough understanding of the present invention. However, in certain instances, well-known or conventional details are not described in order to avoid obscuring the description of the present invention. References to one or an embodiment in this disclosure are not necessarily references to the same embodiment; and such references mean at least one.

Recent developments in wireless communication technology have led to the deployment of a variety of different wireless networks with substantial overlapping coverage in some areas. In this application, a wireless network refers to a set of wireless access points (e.g., base stations) having the same air interface, operated by a service provider (e.g., verizon wireless or Sprint), such that when a mobile unit is in the coverage area of the network, it can access the network through one of the set of wireless access points; and the union of the coverage areas of the wireless access points of the wireless network is the coverage area of the network. Further, data communication refers to the transmission of data in a two-way communication system, although in some embodiments data communication may be unidirectional communication, or may include extracted information embedded in a signal that is propagated whether or not it is required by a receiver. A wireless access point may be considered a cell tower or base station or other wireless transmitter or receiver of a network coupled to other nodes (e.g., the wireless access point is coupled to other nodes by wireless or wireline).

In some areas, particularly urban metropolitan areas, different wireless networks have substantially overlapping coverage. For example, different service providers may offer the same type of wireless service (e.g., cellular telephone communications) in the same area. Further, different types of wireless services, such as wireless telephone services (e.g., cellular telephone services for data, voice, or both) and wireless digital communication services (e.g., wireless local area networks such as Wi-Fi networks, bluetooth, ultra-wideband) may overlap in coverage area. For example, a wireless LAN (local area network) access point (e.g., for IEEE802.11 based wireless networks) may be located within the coverage area of a wireless telecommunications network (e.g., based on the Telecommunications Industry Association (TIA)/Electronic Industry Association (EIA) standards such as IS-95, IS-856, or IS-2000), such as a wireless telecommunications network based on TDMA (time division multiple access), GSM (global system for mobile communications), CDMA (code division multiple access), W-CDMA (wideband code division multiple access), UMTS (joint mobile telecommunications system), TD-SCDMA (time division synchronous code division multiple access), iDEN (integrated digital enhanced network), HDR (high data rate), or other similar cellular networks.

At least one embodiment of the present invention seeks to provide a comprehensive system that uses these disparate wireless signal sources to support position location to determine measurements and obtain assistance information (e.g., location and coverage area of access points, doppler frequency offset for visible SPS satellites, SPS ephemeris data), resulting in a flexible and ubiquitous navigation solution. In this overall system, when information about an access point is available (e.g., a base station almanac such as the location and coverage area of the base station), the information is used and can be enhanced. When it is not available, the system may automatically collect and enhance the information for the benefit of future location attempts.

At least one embodiment of the present invention uses wireless signals transmitted from access points of more than one wireless network to combine information such as SPS observations, wireless network observations, terrain elevation information, and other information to obtain a position solution for a mobile station. In one embodiment of the present invention, a mobile station of a hybrid position system communicates information through access points of more than one wireless network (in two-way communication) to assist in SPS signal acquisition, time stamping measurements and other operations at the mobile station. In one embodiment of the invention, a mobile station of a hybrid location system performs measurements using signals from access points of different wireless networks while communicating with a remote server using one or more wireless networks.

Typically, information describing the identification, location, and coverage area of a sector of a wireless network is stored in a base station almanac that has been used in a hybrid positioning system using a single wireless network. However, when different wireless networks (e.g., different service providers or different types of networks) have overlapping coverage, a typical mobile station does not have access to information for the access points of the different wireless networks, even though wireless signals transmitted from the access points of the different wireless networks are over-the-air and available to the mobile station. This is typically because the mobile station is allowed or authorized to have access to one wireless network and not another. A simple example of this is a mobile phone (cell phone) that has been granted access to a first Wireless network (e.g., a mobile phone network operated by a service provider such as Verizon Wireless), but has not yet been granted access to a second Wireless network (e.g., Sprint's mobile phone network) or to a third Wireless network (e.g., a Wi-Fi "hotspot").

In an embodiment of the present invention, information from a small and localized transmitter, such as an IEEE802.11 wireless LAN access point, is incorporated into a wireless navigation solution when available. In many cases, the location information for these transmitters is not well known. In some cases, "almanac" information that describes the physical characteristics of the wireless network (e.g., the ID, location, and coverage area of the access point) is not available to users who may want to use it. Some network providers may choose not to share this information, while others may not make it available. In one embodiment of the invention, information for deriving physical characteristics of a network is collected from a mobile station communicating using another wireless network. In one embodiment of the invention, using wireless signals available over the air from different wireless networks and the mobile station's ability to be used for position determination (e.g., a mobile phone having a GPS receiver or having a portion of a GPS receiver), the mobile station harvests information about access points of the different wireless networks, which may not typically be under the control of an operator of the wireless network over which the mobile station typically performs data communications. The harvested information is used to derive location information (e.g., location, coverage area) about the access point, which may be used to aid future location determinations for hybrid location determination.

In one embodiment of the present invention, the signal used to provide time information and/or frequency information to the mobile station is different from the signal on which the data communication process is performed.

In one embodiment of the invention, mobile stations that support multiple wireless communication interfaces (e.g., IEEE802.11 [ and other IEEE802 standards such as 802.15, 802.16, and 802.20 ], Bluetooth, UWB [ ultra Wide band ], TDMA, GSM, CDMA, W-CDMA, UMTS, TD-SCDMA, IDEN, HDR, or other similar networks) are used to use multiple wireless networks. Such a mobile station may have, for example, several different parts in the communication means supporting data transmission and/or reception for these different communication interfaces. Thus, one portion may handle transmission and/or reception of Wi-Fi signals (e.g., IEEE802.11 or 802.16), and another portion of the communications component may support a cellular telephone interface, such as a CDMA interface. This also gives the user an alternative communication path to choose when deciding on communication. For example, availability, coverage, cost, data speed, and ease of use may be considered when selecting which communication path to use.

In one embodiment of the invention, a first wireless network is used for communication and positioning, and a second wireless network is used for positioning and optionally communication. For example, each of these wireless networks may use a completely different air interface (e.g., different TIA/EIA standards), such as the air interface used for a typical wireless mobile phone (e.g., TDMA, GSM, CDMA, W-CDMA, UMTS, TD-SCDMA, IDEN, HDR, or other similar cellular networks) or some other wireless air interface, such as according to IEEE802.11, Bluetooth, or UWB. Even when only one wireless network is available for communication, a plurality of these wireless networks are still used for positioning purposes. Advantages of the mixing method according to at least some of the embodiments of the invention include: improved redundancy for a more fail-safe solution, higher positioning availability, better accuracy and faster settling time.

FIG. 4 shows an example of a hybrid positioning system according to an embodiment of the invention. In fig. 4, the mobile station 407 utilizes over-the-air signals transmitted from the wireless access point 403 of wireless network a and the wireless access point 405 of wireless network B for position determination. In one embodiment of the invention, the mobile station includes a receiver for receiving SPS signals from SPS satellites (e.g., GPS satellites, not shown in fig. 4). Timing measurements (e.g., pseudoranges, round trip times, signal times of arrival, signal time differences of arrival) based on wireless signals (and SPS signals) from one or both of wireless networks a and B may be used to determine a position of the mobile station. It should be appreciated that, in general, each of wireless networks a and B includes a number of access points (e.g., cellular base stations such as wireless access points 403 and 405). Wireless networks a and B may use the same type of air interface operated by different service providers, or they may operate with the same communication protocol but at different frequencies. However, wireless networks A and B may also use different types of air interfaces (e.g., TDMA, GSM, CDMA, W-CDMA, UMTS, TD-SCDMA, IDEN, HDR, Bluetooth, UWB, IEEE802.11, or other similar networks) operated by the same service provider or by different service providers.

In an embodiment of the present invention, the location determination is performed at the location server 411 shown in the example depicted in FIG. 4. The mobile station 407 communicates information extracted from observed SPS signals (e.g., SPS pseudorange measurements, SPS information records for comparison to determine signal reception times) and information extracted from observed wireless signals (e.g., identification of access points, round trip or one-way time measurements between the mobile station 407 and at least one of the wireless access points, received signal levels) to the location server over one of the wireless networks, such as wireless network a (e.g., when the mobile station is a user of wireless network a and not a user of wireless B). Servers 413 and 415 maintain almanac data for wireless networks a and B, respectively. In an exemplary embodiment, such almanac data may simply be a database listing the latitude and longitude for each wireless access point specified by the identification information (e.g., MAC address or cell tower identifier, etc.). The location server 411 uses the information communicated from the mobile station and the data in the almanac servers 413 and 415 to determine the location of the mobile station. The location server 411 may determine the location of the mobile station in many different ways. It may retrieve the locations of the wireless access points 403 and 405, e.g., from servers 413 and 415, and calculate the location of the mobile station 407 using those locations and range measurements indicating the distance between the mobile station 407 and the points 403 and 405, as well as SPS pseudorange measurements and SPS ephemeris information. U.S. patent No. 5,999,124 provides a discussion of how the position of a mobile station may be calculated in conjunction with SPS pseudorange measurements and range measurements from a single wireless network. Alternatively, if many (e.g., more than 3) of these range measurements can be made, location server 411 may only use terrestrial range measurements (or other types of measurements such as signal strength measurements) for multiple wireless access points of multiple wireless networks to calculate the location; in this case, there is no need to obtain SPS pseudoranges or SPS ephemeris information. If SPS pseudoranges to SPS satellites are available, these pseudoranges may be combined with SPS ephemeris information obtained by the mobile station or by a set of GPS reference receivers as described in U.S. Pat. No. 6,185,427 to provide additional information in the position calculation.

Network 401 may include a local area network, one or more intranets, and the internet for the exchange of information between the different entities. It should be appreciated that servers 411, 413, and 415 may be implemented as a single server program, or different server programs in a single data processing system or in separate data processing systems (e.g., maintained and operated by different service providers).

In one embodiment of the invention, different service providers operate wireless networks a and B that are used by the mobile station for position determination. A typical mobile station is a user of only one of wireless networks a and B and, therefore, the mobile station is authorized to use (and have access to) only one wireless network. However, it is also generally possible to receive at least signals from a wireless network that is not subscribed to, and thus also to make distance measurements or signal strength measurements with respect to wireless access points in the wireless network that is not subscribed to. A specific example of this would involve the user of a tri-mode CDMA cellular telephone that can receive PCS band signals (such as, for example, from a Wireless network operated by a first service provider Sprint) and can also receive other CDMA signals at other frequencies (such as, for example, from a Wireless network operated by a second service provider Verizon Wireless). If the user has subscribed only to the Sprint's wireless network, the user's phone (in the form of a mobile station) is authorized to operate with the Sprint's wireless network instead of Verizon's wireless network. A user may use a phone in an environment where only one Sprint wireless access point (e.g., Sprint cellular base station) is capable of radio communication with the user's phone, but there are many Verizon wireless access points in this environment that are within radio communication range of the user's phone. In this case, the phone may also obtain SPS assistance data from the location server, if needed, through Sprint's wireless network, and transmit SPS pseudoranges obtained at the phone to the location server. However, it would not be possible to obtain more than one distance measurement to a wireless access point unless a distance measurement to Verizon's wireless access point was obtained. With an embodiment of the invention, the phone obtains distance measurements to available Verizon wireless access points, providing at least a few distance measurements (e.g., distances between the phone and Verizon cellular base stations) that can be used in location calculations performed to determine the location of the phone.

The service provider maintains almanac information on servers 413 and 415, respectively. Although the mobile station 407 has communication access to only one of the wireless networks, the location server 411 may have access to both servers 413 and 415 to access the base station almanac data. After determining the identity of the base stations (e.g., wireless access points 403 and 405) of both wireless networks a and B, the mobile station 407 transmits the base station identification to the location server 411, which uses servers 413 and 415 to retrieve the respective locations of the base stations, which can be used to determine the location of the mobile station.

Alternatively, it is not necessary that the service providers cooperatively share almanac data. For example, an operator of location server 411 maintains both almanac servers 413 and 415 (e.g., through a survey process to obtain almanac data, or through a data harvesting process using a mobile station, which will be described in detail in fig. 6 and 7 and 10).

In one embodiment of the invention, the mobile station 407 uses both wireless a and B to communicate with the location server (rather than using only one of the wireless networks for communication purposes). As is known in the art, different types of information may be exchanged between a mobile station and a location server for use in location determination. For example, location server 411 may provide mobile station 407 with doppler frequency offset information for satellites in view of the mobile station (e.g., via wireless network a); and the mobile station may provide pseudorange measurements, base station identification information, and related range measurements (e.g., round trip time measurements) for SPS signals to the location server for use in location calculations (e.g., over wireless network B) for the mobile station. In one embodiment of the invention, a mobile station is able to communicate with a location server over more than one wireless network when it is in the coverage area of the wireless network. However, a balance between cost and performance may be indicated for communication with the server using one of the wireless networks, while using the other wireless network only for timing measurements (or other measurements, such as received signal levels) or for assistance in measurements, such as obtaining time information from wireless transmissions from an access point for time stamping measurements (e.g., to solve the ambiguity problem), or locking to the exact carrier frequency of a wireless cellular base station for calibrating the local oscillator of the mobile station.

In one embodiment of the invention, the location of the mobile station is determined at a location server using information communicated from the mobile station and then transmitted back to the mobile station. Alternatively, position calculations may be performed at the mobile station using assistance information from a position server (e.g., doppler frequency offsets of visible satellites, location and coverage area of access points, differential GPS data, altitude assistance information).

FIG. 5 shows another example of a hybrid positioning system according to an embodiment of the invention. An access point of a wireless network, such as cellular base station 503, is used for communication between the mobile station 507 and the location server 511. A method for determining the position of the mobile station 507 may use SPS signals (e.g., from satellites 521), wireless signals from access points of a wireless network for data communications (e.g., cellular telephone base station 503), and wireless signals from access points of other wireless networks, such as those from access point B (505) which may be base stations of different wireless cellular telephone networks (e.g., operated by different service providers or using different air interfaces) and from access point a (509) which may be a wireless LAN access point (e.g., a bluetooth access point or a Wi-Fi wireless access point).

Typically, wireless LAN access points (or other similar low power transmitters) have a small coverage area. The smaller coverage area of this access point provides a good estimate of the location of the mobile station when available. Further, wireless LAN access points are typically located near or inside buildings where the availability of other types of signals (e.g., SPS signals or wireless telephone signals) may be low. Thus, when these wireless transmissions are used with other types of signals, the performance of the positioning system can be greatly improved.

In one embodiment of the invention, wireless signals from different wireless networks may be used for position determination. For example, wireless signals from different wireless networks may be used to determine the identity of the respective access point, which is then used to determine the location and coverage area of the respective access point. When accurate range information (e.g., round trip time or signal travel time between an access point and a mobile station) is available, the range information and location of the access point may be used to obtain a hybrid positioning solution. When approximate range information is available (e.g., received signal levels that may be approximately correlated to the estimated range), the location of the access point may be used to estimate the location of the mobile station (or determine an estimated altitude of the mobile station). Further, the mobile station may calibrate the mobile station's local oscillator using a precise carrier frequency from one of the wireless networks (e.g., from access point 505 or 509), which may not be the wireless network used for data communication purposes. More details regarding locking to the precise carrier frequency of a wireless signal to provide a reference signal at an SPS receiver for signal acquisition may be found in U.S. patent No. 5,874,914. Further, the mobile station may use accurate time information in wireless signals from one of the wireless networks (e.g., from access point 505 or 509), which may not be a wireless network for data communication purposes. More details regarding the use of accurate time information (e.g., timing marks or system time) for time stamping may be found in U.S. patent No. 5,945,944.

Since some of the access points of different wireless networks do not have well-known almanac data (e.g., location of the wireless access point, coverage area of the wireless access point), an embodiment of the present invention derives the almanac data from information collected from the mobile station. Fig. 6 illustrates a method of determining the location of a wireless access point according to an embodiment of the invention. In fig. 6, the location server does not know the location of the access point antenna 601. To calculate the position of the access point, the location server correlates the position of one or more mobile stations with their respective distances to the access point, when executedThe distance is obtained from the mobile station when determining the position of (a). For example, position L₁(611) The mobile station at determines the distance R to the access point antenna 601₁(613). The mobile station obtains measurements based on SPS signals (e.g., measurement of SPS pseudoranges and extraction of SPS ephemeris information from the SPS signals) and wireless transmissions (e.g., range measurements). The mobile station may use the measurements to calculate its position and transmit the calculated position to a position server having: i) distance to an access point antenna; and ii) the identity of the access point antenna. Alternatively, the mobile station may measure i); ii) a distance to an access point antenna; and iii) the identity of the access point antenna is transmitted to a location server, which uses the measurements to calculate the location of the mobile station and stores the range measurements (e.g., R)₁、R₂And R₃) And the corresponding position (e.g., L)₁、L₂And L₃). When a number of data points are available, each of which correlates the position of the mobile station to the distance from the mobile station to the access point antenna, the location server determines the position of the access point antenna. As can be seen in FIG. 6, as few as three distance measurements (R)₁、R₂And R₃) And its corresponding position (L)₁、L₂And L₃) It is sufficient to specify a particular location of the identified access point (which is shown at the intersection of the three circles specified by the three distances). Various methods that have been used in the art to calculate the position of a mobile station based on range information may be used to calculate the position of an access point. Note that the data points may be from a single mobile station or from many mobile stations.

In addition, the accumulated mobile station location data points show the coverage area of the access point (e.g., in a profile of mobile locations). When the location of the access point is not known, the collected data points can be used to estimate the location and coverage of the access point. When an initial estimate of the location of an access point is available, the collected data points can be used to refine the estimate. The collection and enhancement process may be a continuous process during the location server service. Note that the collecting and enhancing operations may be performed on a different server than the location server. For example, in one embodiment of the present invention, the collection and enhancement operations are performed in almanac server 513, and almanac server 513 communicates with location server 511 when performing hybrid position determination for mobile stations.

However, the mobile station of the location server may not be able to obtain accurate information of the distance to some access points. Fig. 7 illustrates another method of determining location information for a wireless access point according to an embodiment of the invention. More data points (e.g., 711, 713, 715, 721, 723, 725) for the location of a mobile station that may receive a signal from an access point (e.g., 703) define the coverage area (e.g., 705) of the access point (e.g., by a profile of locations, around a minimum circumference of the data points). From the coverage area, the location server may compute an estimated location of the access point (e.g., the geometric center of the coverage area). Further, range information (e.g., indicators of received signal level, round trip time) may be used to define weights (e.g., closer to the access point, greater weight) for determining a weighted average of the coverage areas from which to determine an estimated location of the access point. Further, in one embodiment, the location server determines the likelihood that the mobile station is located at a particular location from the statistics (statistics) of the mobile station, assuming that certain distance information is specified. Other information, such as signal levels of wireless transmissions from other transmitters, may then be further used to narrow the possible locations of the mobile station.

For example, a wireless LAN access point is located inside the building 701. While SPS signals (e.g., signals from SPS satellites 741-745) and wireless cellular telephone signals (e.g., signals from cellular base station 751) may be weaker inside building 701, the location of the mobile station may be readily determined (e.g., without using signals from access point 703) at certain locations around the building (e.g., location 711-725, which may be outside of the building or at certain locations inside the building, such as near a window). In one embodiment of the invention, the identification of the access point is determined and sent to a server with the location of the mobile station (or information specifying the location of the movement, such as pseudoranges to visible satellites) for use in determining the coverage area (and/or location) of the access point 703. Location information (e.g., coverage area, location) for the access point may be maintained at the server (or a different server). Location information about access points may be used to help determine the location of a mobile station in the event of blockage of some of the SPS signals and cellular telephone signals when the mobile station is inside a building (or at a location near the building).

It should be appreciated that some access points may move from one location to another. In one embodiment of the invention, a server tracks collected location information about one or more mobile stations that receive transmissions from an access point to determine whether the access point is moved. For example, the server may compare the old coverage area to the latest coverage area (e.g., by comparing the center and radius of the coverage areas) to determine whether the access point is moved. Alternatively, the server may periodically discard old information in view of newly collected information. Further, the server may weight the collected information such that newly collected data is more weighted in determining the coverage area and/or location of an access point, and the impact from previously collected data may eventually decrease over time. Further, the server may determine whether the access point moves frequently; and if the access point moves frequently, the access point may lose its qualification as a reference point for location determination. Further, in an embodiment, an access point is removed from the database when it is not observed for a certain period of time; similarly, when a new access point is observed, it is added to the database. Thus, the server can update information about the access points on an ongoing basis (in an accompanying basis).

In at least one embodiment of the present invention, the mobile station may determine its position without a communication link. The mobile station has a memory (e.g., for cellular telephone access, or for wireless LAN access) for storing information about the location of the mobile station and at least some of the corresponding received signal levels or range measurements for a number of wireless access points. When a communication link is available (e.g., a wired connection through a communication port of the mobile station or a wireless connection through a transceiver of the mobile station), the mobile station transmits the data to the server. Alternatively, the mobile station may directly use the stored information to derive location information about the access point to determine its own location, when desired.

Fig. 8 illustrates a general hybrid location determination method using a plurality of wireless networks according to an embodiment of the present invention. In operation 801, a mobile station receives wireless signals transmitted from a plurality of wireless access points of different wireless networks (e.g., wireless networks of different air interfaces, wireless networks of different service providers, wireless networks operating at different frequencies, wireless networks using different communication protocols, etc.). In operation 803, the mobile station uses the wireless signals from each of the access points of the different wireless networks to determine the location of the mobile station (e.g., determine the identity of the access points, lock the mobile station's local oscillator to the precise carrier frequency of the wireless signals, obtain a timing indicator from the wireless signals, determine the signal transmission delay between the mobile station and one of the access points, communicate with the server). In general, although a mobile station may perform many similar operations using wireless signals from access points of some different wireless networks, the mobile station may perform different operations using wireless signals from access points of different wireless networks. In operation 805, the mobile station communicates with a server using at least one of the different wireless networks to determine a location of the mobile station. Typically, a mobile station communicates with a server using only one of the different wireless networks; however, the mobile station may communicate with the server using more than one wireless network (e.g., to transmit a receive time at the access point, a transmit round trip time, or other information to or from the location server for a signal transmitted from the mobile station).

Fig. 9 shows a hybrid position determination method using two wireless networks for communication with a server according to an embodiment of the present invention. Operation 821 receives, at a mobile station, SPS signals transmitted from one or more SPS satellites and wireless signals transmitted from a plurality of wireless access points of one or more wireless networks. The mobile station may use wireless signals received from one or more wireless networks to assist in SPS signal acquisition (e.g., extract doppler frequency offsets for satellites in view of the mobile station, calibrate the mobile station's local oscillator, obtain timing indicators to timestamp measurements). The mobile station uses SPS signals to determine pseudoranges to the satellites in view, and the mobile station uses wireless signals from wireless access points to identify access points and perform range measurements to the wireless access points for position determination. These received signals are typically propagated from the satellite's transmitter and the wireless access point, and are made available to any mobile station that chooses to use the signal. Operation 823 communicates first information (e.g., a record of SPS information) between the mobile station and a server using an access point of a first wireless network (e.g., a wireless local area network). Operation 825 communicates second information (e.g., doppler frequency offsets for visible SPS satellites, ephemeris data) between the mobile station and the server using an access point of a second wireless network (e.g., a wireless cellular telephone network). Operation 827 determines a position of the mobile station from the communication of the first information and the second information. Availability, coverage, cost, data speed, and ease of use are generally considered when selecting which communication path to use. In addition, the mobile station may use different communication paths at different locations. For example, when a mobile station is within the coverage area of a wireless LAN (e.g., a home network), the mobile station may use the wireless LAN (e.g., through the internet) to communicate with a server information (e.g., doppler frequency offset) that does not need to traverse through the base stations of the wireless cellular telephone system and use the base stations of the wireless cellular telephone system to transmit information about the base stations (e.g., round trip time measurements for the base stations of the wireless cellular telephone system). In another example, the mobile station may choose to use a wireless cellular telephone system or a wireless LAN for communication based on communication cost and availability. In one embodiment of the present invention, the mobile station automatically determines the communication path based on a set of rules (e.g., availability, cost, priority, and others) that may be specified by a user of the mobile station or may be set by one of the wireless networks as a default setting.

Fig. 10 illustrates a method of generating location information regarding a wireless access point in accordance with an embodiment of the present invention. Operation 841 detects, at the mobile station, a wireless signal transmitted from a wireless access point (e.g., a wireless access point that complies with the IEEE802.11 standard for wireless local area networks, or other type of ground-based wireless transmitter that transmits signals with its identification information). Note that in the present invention, the wireless access point does not include a satellite-based transmitter. Operation 843 determines identification information for the wireless access point from the wireless signal (e.g., a MAC address of the wireless access point or an identifier of the cellular base station), which may be a unique identifier. Operation 845 determines a location of the mobile station (e.g., at the mobile station or at a location server). For example, the mobile station may calculate a position based on pseudorange measurements and other range information; or the mobile station may transmit the pseudorange measurements and range information to a location server that calculates the location of the mobile station (and the location server may send the calculated location back to the mobile station). Operation 847 correlates the location of the mobile station with identification information of the wireless access point. This correlation may be transmitted to a location server so that future location operations of the mobile station may use the location and identification information to determine the location of the identified wireless access point. Operation 849 generates location information regarding the wireless access point (e.g., access point almanac, statistics of the coverage area of the wireless access point). Typically, the correlation data is sent to a server (e.g., a location server, or an access point almanac server) that generates location information for the access point based on a number of locations of one or more mobile stations reporting the reception of signals transmitted from the access point. The location information about the wireless access point may be derived from a weighted average method as described above (or other methods, such as using the range information shown in fig. 6). However, the mobile station may also track the correlation and derive location information about the wireless access point (e.g., from data points collected at different time instances). The location information about the wireless access point may then be used for location determination.

Fig. 11 shows a hybrid position determination method using a wireless network for communication and another wireless network for positioning parameter measurement according to an embodiment of the present invention. Operation 861 detects, at a mobile station, a wireless signal transmitted from a wireless access point (e.g., a wireless access point complying with the IEEE802.11 standard for wireless local area networks, or a cellular communication base station) of a first wireless network (e.g., a wireless local area network or a cellular telephone communication system). Operation 863 determines identification information (e.g., a MAC address, or a base station ID) of the wireless access point from the wireless signal. Operation 865 uses the identification information to retrieve location information (e.g., an access point almanac) for the wireless access point. For example, the mobile station may transmit identification information for the wireless access point to a location server, which uses the identification information (e.g., from a database, or from another server such as an access point almanac server) to retrieve location information for the wireless access point. In another example, a mobile station maintains location information about a wireless access point in memory; thus, the location information is simply retrieved from the memory of the mobile station. Operation 867 determines a location of the mobile station using the location information and using a communication link between the mobile station and a wireless access point of a second wireless network (e.g., a cellular telephone network). For example, satellite assistance data (e.g., doppler frequency offset) for SPS signal acquisition or timing measurements (e.g., pseudoranges or SPS signal time of arrival) is communicated over the second wireless network to determine the position of the mobile station.

Fig. 12 shows another exemplary method of the present invention. In this method, in operation 901, a mobile station receives a first signal transmitted from a first wireless access point of a first wireless network. The first wireless network may support bi-directional communication between nodes within the first wireless network and between nodes outside of this network. In operation 903, at least one distance measurement is determined using the first signal. Additional range measurements (and identification information thereof) are obtained for other wireless access points of the first wireless network if additional signals are also available from these other wireless access points. In an alternative embodiment of operation 903, the mobile station may make another measurement (e.g., a signal strength measurement of the first signal) without attempting to make a range measurement using the first signal. In an exemplary embodiment, a travel time of a first signal from a first wireless access point to a mobile station is measured and an identification of this first wireless access point is received from the first wireless access point. In operation 905, a second signal is communicated between the mobile station and a second wireless access point of a second wireless network different from the first wireless network. In this operation, the mobile station may receive a second signal (which may include SPS assistance data, etc.) from a second wireless access point. In operation 907, the mobile station communicates with the server to determine the location of the mobile station, and such communication may occur through the second wireless access point. For example, in operation 907, the mobile station may transmit the distance measurement and identification information performed in operation 903, and the SPS pseudoranges obtained by the mobile station, to the server through the second wireless access point. The identification information is used to obtain the location of the wireless access point, range measurements (or other measurements) to the wireless access point are obtained, and the server can then use at least some of the available measurements (e.g., SPS pseudoranges to SPS satellites and range measurements or other measurements to different terrestrial wireless access points) to determine the location of the mobile station. Alternatively, rather than the server doing this, the mobile station may determine its position using the range measurements and SPS pseudoranges and using information provided by the server, such as the positions of identified wireless access points in one or both of the wireless networks.

The first wireless network in fig. 12 may be a wireless local area network, and in this case, the first wireless access point may be a wireless router operating according to the Wi-Fi standard. Alternatively, the first wireless network may be a wireless cellular telephone network operated by the first service provider, and the second wireless network may be another (different) wireless cellular telephone network operated by the second service provider, and the mobile station is authorized to operate only with the second wireless network, instead of the first wireless network, which may be a cellular telephone with an integrated GPS receiver. Various other alternative operations discussed herein may also be applied to this example of fig. 12.

FIG. 13 is another example of the method of the present invention. In this example, in operation 931, the mobile station obtains identification information of a first wireless access point of a first wireless network that is accessible (e.g., within radio communications) by the mobile station. This identification may be a MAC address (e.g., for an ethernet local area network) or a cellular telephone base station (e.g., "cell tower") identifier. In operation 933, during the location determination operation, the mobile station transmits identification information to a server (e.g., a location server) through a second radio access point of a second wireless network. In this example, the second wireless network is different from the first wireless network (e.g., a different air interface, a different service provider, etc.). Next, in operation 935, the server determines the location of the first wireless access point using the identification information of the first wireless access point (such as in fig. 14, which may be harvested/collected by the methods described herein). In operation 935, the server may also use other data (e.g., SPS pseudoranges determined at a GPS receiver integrated into the mobile station and then transmitted to the server) to determine the position of the mobile station. The server may combine SPS pseudoranges with measurements of signals from wireless access points, for example, to determine the position of the mobile station. Alternatively, SPS pseudoranges may be combined with known wireless access point locations (especially in the case of wireless LANs with shorter signal ranges). In another alternative operation of operation 935, the server may provide assistance data (e.g., the location of the first wireless access point and possibly other data such as doppler data for SPS satellites, etc. in view of the mobile station) to the mobile station, but the server does not calculate the location of the mobile station; instead, the mobile station performs a position solution using at least some of the available measurements (e.g., SPS pseudoranges, range measurements, or other measurements with respect to wireless access points of one or all available wireless networks) and assistance data available from a server.

Fig. 14 shows another exemplary method of the present invention. This method ultimately determines the location of the wireless access point such that future location determination operations for the mobile station may be performed using multiple wireless networks as described herein. In operation 971, data is collected. This data specifies a plurality of locations of the mobile station at which wireless signals transmitted from at least a first wireless access point of the first wireless network are received during the plurality of location determinations. In operation 973, the mobile station may receive a signal from the first wireless access point and also communicate between the mobile station and at least a second wireless access point of a second wireless network (which is different from the first wireless network). Such communication with the second wireless network may be in order to provide information for gathering data for determining the location of the wireless access point of the first wireless network. In operation 975, a location of at least the first wireless access point is determined (e.g., in the manner shown in fig. 6) from a defined coverage area defined by the plurality of locations.

FIG. 2 shows an example of a data processing system that may be used as a server in various embodiments of the invention. For example, as described in U.S. patent No. 5,841,396, the server (201) may provide assistance data such as doppler effect or other satellite assistance data to a GPS receiver in the mobile station. Additionally, or alternatively, the same server or a different server, rather than the mobile station, may perform final position calculations (after receiving pseudoranges or other data from which pseudoranges may be determined from the mobile station) and may then forward this position determination to the base station or to some other system. The data processing system, which is a server (e.g., location server, almanac server), typically includes a communication device 212 such as a modem or network interface. The location server may be coupled to many different networks through a communication device 212, such as a modem or other network interface. These networks include one or more intranets, the network, a cellular switching center or multiple cellular switching centers 225, land-based telephone system converters 223, cellular base stations (not shown in FIG. 2), GPS receivers 227, or other processors or location servers 221.

As is well known in the art (see, e.g., fig. 1), a plurality of cellular base stations are typically arranged to cover a geographic area with radio coverage, and these different base stations are coupled to at least one mobile switching center. Thus, multiple base stations will be geographically distributed but coupled together through a mobile switching center. The network 220 may be connected to a network of reference GPS receivers that provide differential GPS information and may also provide GPS ephemeris for use in calculating the position of the mobile system. The network is coupled to the processor 203 through a modem or other communication interface. The network 220 may be connected to other computers or network components. Likewise, the network 220 may be connected to a computer system operated by an emergency operator, such as a public safety answering point responding to a 911 telephone call. Various examples of methods of using location servers are described in numerous U.S. patents including: U.S. Pat. nos. 5,841,396, 5,874,914, 5,812,087, and 6,215,442.

The server 201 comprises a bus 202 coupled to a microprocessor 203 and a ROM 207 and volatile RAM 205 and a non-volatile memory 206, said server 201 being in the form of a data processing system. As shown in the example of fig. 2, the processor 203 is coupled to a cache memory 204. A bus 202 interconnects these various components together. While FIG. 2 shows that the non-volatile memory is a local device coupled directly to the rest of the components in the data processing system, it will be appreciated that the present invention may utilize a non-volatile memory which is remote from the system, such as a network storage device which is coupled to the data processing system through a network interface such as a modem or Ethernet interface. As is well known in the art, the bus 202 may comprise one or more buses connected to each other through different bridges, controllers and/or adapters. In many cases, the location server may perform its operations automatically without human assistance. In some designs where human interaction is desired, the I/O controller 209 may communicate with a display, keyboard, and other I/O devices.

Note that while FIG. 2 illustrates various components of a data processing system, it is not intended to represent any particular architecture or manner of interconnecting the components as such details are not germane to the present invention. It will also be appreciated that network computers and other data processing systems which have fewer components or perhaps more components may also be used with the present invention and may act as a position server or PDE (position determination entity).

In some embodiments, the methods of the present invention may be performed on a computer system that is simultaneously used for other functions, such as cellular exchanges, messaging services, and the like. In these cases, some or all of the hardware of FIG. 2 would be shared for several functions.

It will be apparent from this description that aspects of the invention may be embodied, at least in part, in software. That is, the techniques may be performed in a computer system or other data processing system in response to the processor's execution sequence of instructions contained in a memory such as ROM 207, volatile RAM 205, non-volatile memory 206, cache 204, or a remote storage device. In various embodiments, hardwired circuitry may be used in combination with software instructions to implement the present invention. Thus, the techniques are not limited to any specific combination of hardware circuitry and software nor to any particular source for the instructions executed by the data processing system. In addition, throughout the description, various functions and operations are described as being performed by or caused by software code to simplify description. However, those skilled in the art will recognize that such expressions refer to the functionality resulting from execution of the code by a processor, such as the processor 203.

A machine-readable medium may be used to store software and data which when executed by a data processing system causes the system to perform various methods of the present invention. As shown in FIG. 2, such executable software and data may be stored in various places including, for example, ROM 207, volatile RAM 205, non-volatile memory 206, and/or cache 204. Portions of such software and/or data may be stored in any of these storage devices.

Thus, a machine-readable medium includes any mechanism that provides (i.e., stores and/or transmits) information in a form accessible by a machine (e.g., a computer, network device, personal digital assistant, manufacturing tool, any device with a set of one or more processors, etc.). For example, a machine-readable medium includes recordable/non-recordable media (e.g., Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk storage media, optical storage media, flash memory devices (flash memory devices), etc.), as well as electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), etc.

Fig. 3 shows a block diagram representation of a mobile station according to an embodiment of the invention. The mobile station includes a portable receiver that combines a communication transceiver with a GPS receiver for use in an embodiment of the invention. The combined mobile unit 310 includes circuitry for performing the functions required for processing GPS signals and for processing communication signals received over the communication link. A communication link, such as communication link 350 or 360, is typically a radio frequency communication link to another component, such as base station 352 having a communication antenna 351 or a wireless LAN access point 362 having an antenna 361. Although fig. 3 illustrates an embodiment in which the communication antenna 311 is used to receive signals from different types of wireless access points (e.g., from the access point 362 for a wireless LAN and from the serving cellular telephone base station 352), the combined receivers may use separate and different antennas to receive signals for different air interfaces. Moreover, the combined receiver may use separate and distinct components to at least partially process the received antenna signals, and may or may not share some components in processing wireless signals for different air interfaces. For example, the combined receivers may have separate circuitry for RF signal processing and may share the same data processor resources. Various combinations and variations of the combined receivers will be apparent to those skilled in the art from this description.

The portable receiver 310 is an example of a combined GPS receiver and a communications receiver and transmitter. The communication receiver and transmitter may be implemented as multiple receivers and transmitters for different wireless networks. For example, the communication transceiver 305 may include one transceiver portion for receiving and/or transmitting cellular telephone signals and another transceiver portion for receiving and/or transmitting Wi-Fi signals. The receiver 310 comprises a GPS receiver platform including acquisition and tracking circuitry 321 and communications transceiver component 305. Acquisition and tracking circuit 321 is coupled to GPS antenna 301 and communication transceiver 305 is coupled to communication antenna 311. GPS signals (e.g., signals 370 transmitted from satellites 303) are received by a GPS antenna 301 and input to acquisition and tracking circuitry 321 that obtains PN (pseudo random noise) codes for the various received satellites. Data (e.g., correlation indicators) generated by circuit 321 is processed by processor 333 for transmission (e.g., transmission of SPS pseudoranges) by transceiver 305. Communication transceiver 305 contains a transmit/receive converter 331 that routes communication signals (typically RF) to and from communication antenna 311 and transceiver 305. In some systems, a band splitting filter (bandsplitting filter) or "duplexer" is used in place of the T/R converter. The received communication signals are input to the communication receiver 332 and passed to the processor 333 for processing. The communication signal to be transmitted from the processor 333 is propagated to a modulator 334 and a frequency converter 335. The power amplifier 336 increases the signal gain to an appropriate level for transmission to the base station 352 (or to the wireless LAN access point 362).

In an embodiment of the present invention, the communications transceiver component 305 can be used to communicate (e.g., over communications links 350 and 360) with many different air interfaces (e.g., IEEE802.11, Bluetooth, UWB, TD-SCDMA, IDEN, HDR, TDMA, GSM, CDMA, W-CDMA, UMTS, or other similar networks). In one embodiment of the invention, the communication transceiver component 305 can be used to communicate with one air interface and can be used to receive signals with other air interfaces. In one embodiment of the present invention, the communication transceiver component 305 can be used to communicate over one air interface, and can also be used to extract timing indicators (e.g., timing frames or system time) or calibrate a local oscillator (not shown in fig. 3) of the mobile station using signals in another air interface. More details regarding mobile stations for extracting timing indicators or calibrating local oscillators can be found in U.S. Pat. nos. 5,874,914 and 5,945,944.

In one embodiment of the combined GPS/communications system of the receiver 310, the data generated by the acquisition and tracking circuit 321 is transmitted to a server via a communications link 350 to a base station 352 or via a communications link 360 to a wireless LAN access point 362. The server then determines the position of the receiver 310 based on the data from the remote receiver, the time at which the data was measured, and ephemeris data received from its own GPS receiver or other source of the data. The location data may then be transmitted back to the receiver 310 or other remote location. More details on portable receivers that utilize a communication link can be found in U.S. patent No. 5,874,914.

In one embodiment of the invention, the incorporated GPS receiver includes (or is coupled to) a data processing system (e.g., a personal data assistant or portable computer). The data processing system includes a bus coupled to a microprocessor and a memory (e.g., ROM, volatile RAM, non-volatile memory). The bus interconnects the various components together and also interconnects these components to a display controller and display device and to peripheral devices such as input/output (I/O) devices, as is well known in the art. As is well known in the art, a bus may comprise one or more buses connected to each other through various bridges, controllers and/or adapters. In an embodiment, the data processing system comprises a communication port (e.g. a USB (Universal Serial bus) port, a port for IEEE-1394 bus connection). In one embodiment of the invention, a mobile station stores the location and identification (e.g., MAC address) of a wireless access point (e.g., based on the type of the wireless access point) to extract and enhance location information about the wireless access point using a memory and software program instructions stored in the memory. In one embodiment, the mobile station stores only the location of the mobile station and the identification of the wireless access point for transmission to the server (e.g., via a communication port or wireless communication link) when a communication connection has been established.

Although the method and apparatus of the present invention have been described with reference to GPS satellites, it will be appreciated that the description is equally applicable to positioning systems that utilize pseudolites or a combination of satellites and pseudolites. Pseudolites are ground-based transmitters that propagate a PN code (similar to a GPS signal) that is typically modulated on an L-band carrier signal, generally synchronized with GPS time. Each transmitter may be assigned a unique PN code so as to allow identification by a remote receiver. Pseudolites are useful where GPS signals from orbiting satellites may be difficult to obtain, such as tunnels, mines, buildings, or other enclosed areas. The term "satellite" as used herein is intended to include pseudolites or equivalents of pseudolites, and the term GPS signals as used herein is intended to include GPS-like signals from pseudolites or equivalents of pseudolites.

In the foregoing discussion, the invention has been described with reference to application on the United states Global Positioning Satellite (GPS) System. However, it is clear that these methods are equally applicable to similar satellite positioning systems, and in particular, to the russian GLONASS system and the proposed european galileo system. The GLONASS system differs from the GPS system primarily in that the emissions from different satellites are distinguished from each other by using slightly different carrier frequencies, rather than different pseudo-random codes. In this case, substantially all of the circuits and algorithms previously described are applicable. The term "GPS" as used herein includes these alternative satellite positioning systems, including the russian GLONASS system and the european galileo system.

While the operations in the above examples have been illustrated in a particular order, it will be appreciated from this description that a variety of different operational orders and variations may be used, which are not necessarily limited to the examples illustrated above.

The above examples are described without introducing some details known in the art; as noted in the discussion above, these details can be found in publications such as U.S. Pat. nos. 5,812,087, 5,841,396, 5,874,914, 5,945,944, 5,999,124, 6,061,018, 6,208,290 and 6,215,442, which are all incorporated herein by reference.

In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Claims (74)

1. A method of operating a mobile station, the method comprising:

receiving, at the mobile station, a first signal transmitted from a first wireless access point of a first wireless network, the first wireless access point supporting two-way communication;

determining a distance measurement using the first signal;

communicating second signals between the mobile station and a second wireless access point of a second wireless network different from the first wireless network;

communicating between the mobile station and a server through the second wireless access point of the second wireless network to determine a location of the mobile station.

2. The method of claim 1, further comprising:

calibrating a local oscillator of the mobile station using at least one of the first signal and the second signal.

3. The method of claim 2, further comprising:

locking to a carrier frequency signal in at least one of the first signal and the second signal.

4. The method of claim 2, further comprising:

determining an offset between a carrier frequency signal in at least one of the first signal and the second signal and a frequency of the local oscillator of the mobile station.

5. The method of claim 1, further comprising:

obtaining accurate time information from at least one of the first signal and the second signal.

6. The method of claim 5, further comprising:

a timing mark included in at least one of the first signal and the second signal is determined.

7. The method of claim 5, further comprising:

a system time from at least one of the first signal and the second signal is determined.

8. The method of claim 1, wherein the second wireless access point communicates with the mobile station according to a standard for a wireless local area network.

9. The method of claim 8, wherein the first wireless access point comprises a base station of a wireless cellular communication system.

10. The method of claim 1, further comprising:

determining at least one pseudorange measurement from signals from at least one Satellite Positioning System (SPS) satellite; and is

Determining a position of the mobile station from the range measurements using the first signal and from the at least one pseudorange measurement of signals from the at least one SPS satellite.

11. The method of claim 10, wherein the server receives the at least one pseudorange measurement and the range measurement and determines the position of the mobile station.

12. The method of claim 10, wherein the server provides location assistance data to the mobile station through the second wireless access point.

13. The method of claim 12, wherein the mobile station determines the position of the mobile station, and wherein the position assistance data comprises (a) estimated doppler for SPS satellites; or (b) a list of SPS satellites that account for an estimated position of the mobile station; or (c) satellite almanac information; or (d) an estimated position of the mobile station; or (e) a location of the first wireless access point.

14. The method of claim 1, wherein the mobile station is not authorized to communicate with the first wireless access point by an operator of the first wireless network and is authorized to communicate with the second wireless access point by an operator of the second wireless network.

15. The method of claim 14, wherein the first wireless access point is a first cellular telephone base station, and wherein the second wireless access point is a second cellular telephone base station.

16. The method of claim 1, wherein the range measurements are used to determine the location of the mobile station.

17. The method of claim 1, wherein the first wireless access point and the second wireless access point are each capable of supporting bi-directional communication with an authorized mobile station.

18. The method of claim 1, wherein each of the first wireless access point and the second wireless access point uses one of:

a) TDMA (time division multiple access);

b) GSM (global system for mobile communications);

c) CDMA (code division multiple access);

d) W-CDMA (wideband code division multiple Access);

e) UMTS (universal mobile telecommunications system);

f) TD-SCDMA (time division synchronous code division multiple access);

g) iDEN (integrated digital enhanced network); and

h) HDR (high data rate).

19. The method of claim 1, wherein the second wireless access point comprises a base station of a wireless cellular communication system, and wherein the first wireless access point conforms to one of the following standards:

a) one of the IEEE802.11, 802.15, 802.16, and 802.20 standards for wireless network access;

b) a Bluetooth standard; and

c) a UWB (ultra wide band) standard.

20. A method of operating a mobile station, the method comprising:

receiving, at the mobile station, a first signal transmitted from a first wireless access point of a first wireless network, the first wireless access point supporting two-way communication;

determining a first measurement using the first signal;

communicating second signals between the mobile station and a second wireless access point of a second wireless network different from the first wireless network;

determining a second measurement using the second signal;

determining a pseudorange from SPS signals received by the mobile station to a Satellite Positioning System (SPS) satellite;

determining a position of the mobile station using the first and the second measurements and the pseudoranges.

21. The method of claim 21, further comprising:

calibrating a local oscillator of the mobile station using at least one of the first signal and the second signal.

22. The method of claim 21, further comprising:

locking to a carrier frequency signal in at least one of the first signal and the second signal.

23. The method of claim 21, further comprising:

determining an offset between a carrier frequency signal in at least one of the first signal and the second signal and a frequency of the local oscillator of the mobile station.

24. The method of claim 20, further comprising:

obtaining accurate time information from at least one of the first signal and the second signal.

25. The method of claim 24, further comprising:

a timing mark included in at least one of the first signal and the second signal is determined.

26. The method of claim 24, further comprising:

a system time from at least one of the first signal and the second signal is determined.

27. The method of claim 20, wherein the second wireless access point communicates with the mobile station according to a standard for a wireless local area network.

28. The method of claim 27, wherein the first wireless access point comprises a base station of a wireless cellular communication system.

29. The method of claim 20, wherein the mobile station performs the first and the second measurements and determines the pseudoranges and the position.

30. The method of claim 20, wherein at least one of the first wireless access point and the second wireless access point provides a position assistance data to the mobile station, wherein the position assistance data comprises (a) estimated doppler for SPS satellites; or (b) a list of SPS satellites that account for an estimated position of the mobile station; or (c) satellite almanac information; or (d) an estimated position of the mobile station; or (e) a location of the first wireless access point; or f) a location of the second wireless access point.

31. The method of claim 20, wherein the mobile station is not authorized to communicate with the first wireless access point by an operator of the first wireless network and is authorized to communicate with the second wireless access point by an operator of the second wireless network.

32. The method of claim 31, wherein the first wireless access point is a first cellular telephone base station, and wherein the second wireless access point is a second cellular telephone base station.

33. The method of claim 20, wherein the first wireless access point and the second wireless access point are each capable of supporting two-way communication with an authorized mobile station.

34. The method of claim 20, wherein the first measurement is at least one of (a) a distance measurement representing a distance between the mobile station and the first wireless access point based on a transmission time between the mobile station and the first wireless access point or (b) a signal parameter related to signal strength.

35. The method of claim 20, wherein the second signal is transmitted from the second wireless access point to the mobile station.

36. The method of claim 20, wherein the second signal is transmitted from the mobile station to the second wireless access point.

37. A method of operating a mobile station, the method comprising:

determining, at the mobile station, identification information of a first wireless access point of a first wireless network accessible by the mobile station; and is

Communicating the identification information from the mobile station to a remote server through a second wireless access point of a second wireless network different from the first wireless network during position determination of the mobile station.

38. The method of claim 37, wherein the first and second wireless access points use different air interfaces, and wherein the first wireless access point is communicatively coupled to a first set of nodes of the first wireless network, and wherein the second wireless access point is communicatively coupled to a second set of nodes of the second wireless network.

39. The method of claim 38, wherein the first wireless access point is for accessing a local area network of the first wireless network; and the second wireless access point comprises a cellular base station for a wireless telephone system.

40. The method of claim 38, wherein the first wireless access point is for accessing a local area network of the first wireless network; and the second wireless access point is used for accessing a wide area network of the second wireless network.

41. The method of claim 39, wherein the second wireless access point uses one of:

a) TDMA (time division multiple access);

b) GSM (global system for mobile communications);

c) CDMA (code division multiple access);

d) W-CDMA (wideband code division multiple Access);

e) UMTS (universal mobile telecommunications system);

f) TD-SCDMA (time division synchronous code division multiple access);

g) iDEN (integrated digital enhanced network); and

h) HDR (high data rate).

42. The method of claim 39, wherein the first wireless access point complies with one of the following standards:

a) one of the IEEE802.11, 802.15, 802.16, and 802.20 standards for wireless network access;

b) a Bluetooth standard; and

c) a UWB (ultra wide band) standard.

43. The method of claim 37, wherein a first service provider operates the first wireless network; and a second service provider operates the second wireless network.

44. The method of claim 37, wherein the first wireless access point supports two-way communication.

45. The method of claim 37, further comprising:

determining positioning information indicative of a distance between the mobile station and the first wireless access point; and communicating the location information from the mobile station to the server through the second wireless access point to determine the location of the mobile station.

46. The method of claim 45, wherein the positioning information comprises an indication of a signal level of signals transmitted from the first wireless access point and received at the mobile station.

47. The method of claim 45, further comprising:

determining a measurement of pseudorange to an SPS (satellite positioning system) satellite; and

communicating the pseudorange measurements from the mobile station to the server through the second wireless access point to determine the position of the mobile station, and wherein the identification information is used to determine a position of the first wireless access point.

48. The method of claim 47, further comprising:

determining a position of the mobile station by using at least one of an indication of signal level of signals transmitted from the first wireless access point and the pseudorange measurements to the SPS (satellite positioning System) satellites.

49. The method of claim 37, further comprising:

receiving a location of the first wireless access point from the server.

50. A mobile station of a position determination system, said mobile station comprising:

a wireless communication section for receiving wireless signals transmitted from a first wireless access point of a first wireless network accessible by the mobile station; and

a processor coupled to the wireless communication component to determine identification information of the first wireless access point of the first wireless network, the wireless communication component communicating the identification information from the mobile station to a remote server through a second wireless access point of a second wireless network different from the first wireless network during position determination of the mobile station.

51. The mobile station of claim 50, wherein the first and second wireless access points use different air interfaces, and wherein the first wireless access point is communicatively coupled to a first set of nodes of the wireless network, and wherein the second wireless access point is communicatively coupled to a second set of nodes of the second wireless network.

52. The mobile station of claim 51, wherein the first wireless access point is for accessing a local area network of the first wireless network; and the second wireless access point comprises a cellular base station for a wireless telephone system.

53. The mobile station of claim 52, wherein the second wireless access point uses one of:

a) TDMA (time division multiple access);

b) GSM (global system for mobile communications);

c) CDMA (code division multiple access);

d) W-CDMA (wideband code division multiple Access);

e) UMTS (universal mobile telecommunications system);

f) TD-SCDMA (time division synchronous code division multiple access);

g) iDEN (integrated digital enhanced network); and

h) HDR (high data rate).

54. The mobile station of claim 52, wherein the first wireless access point conforms to one of the following standards:

a) an IEEE802 standard for wireless local area network access;

b) a Bluetooth standard; and

c) a UWB (ultra wide band) standard.

55. The mobile station of claim 50, wherein the first wireless network is operated by a first service provider; and the second wireless network is operated by a second service provider.

56. The mobile station of claim 50, wherein the first wireless access point supports two-way communication.

57. The mobile station of claim 50, wherein the processor further determines positioning information indicative of a distance between the mobile station and the first wireless access point; and the wireless communication component communicates the location information from the mobile station to the server through the second wireless access point to determine the location of the mobile station.

58. A mobile station as defined in claim 57, wherein the location information includes an indication of a signal level of a signal transmitted from the first wireless access point and received at the mobile station.

59. The mobile station of claim 57, further comprising:

an SPS (satellite positioning system) signal receiver coupled to the processor to determine a pseudorange measurement to an SPS satellite;

wherein the wireless communication component communicates the pseudorange measurements from the mobile station to the server through the second wireless access point to determine the position of the mobile station, and wherein the identification information is used to determine a position of the first wireless access point.

60. The mobile station of claim 50, wherein the processor receives a location of the first wireless access point from the server through the communication component.

61. A mobile station, comprising:

a wireless communication component for receiving a first signal transmitted from a first wireless access point of a first wireless network supporting two-way communication and for receiving a second signal transmitted from a second wireless access point of a second wireless network different from the first wireless network, and wherein the mobile station uses the first signal to determine a range measurement; and

an SPS (satellite positioning system) signal receiver coupled to said wireless communication means to determine a pseudorange measurement to an SPS satellite, said wireless communication means communicating with a server to determine a position of said mobile station through said second wireless access point of said second wireless network.

62. The mobile station of claim 61, further comprising:

a local oscillator coupled to the wireless communication component and the SPS signal receiver, the local oscillator being calibrated by the wireless communication component using at least one of the first signal and the second signal.

63. The mobile station of claim 62, wherein said local oscillator locks to a carrier frequency signal in at least one of said first signal and said second signal.

64. The mobile station of claim 61, wherein said wireless communication means obtains accurate time information from at least one of said first signal and said second signal.

65. The mobile station of claim 64 wherein said accurate time information is obtained from a timing mark of at least one of said first signal and said second signal.

66. The mobile station of claim 64 wherein said accurate time information comprises a system time from at least one of said first signal and said second signal.

67. The mobile station of claim 61 wherein said wireless communication means communicates with said second wireless access point according to a standard for a wireless local area network.

68. The mobile station of claim 67, wherein the first wireless access point comprises a base station of a wireless cellular communication system.

69. The mobile station of claim 61, wherein the server provides location assistance data to the mobile station through the second wireless access point.

70. The mobile station of claim 69, wherein the mobile station determines the position of the mobile station, and wherein the position assistance data comprises (a) an estimated Doppler for SPS satellites; (b) a list of SPS satellites in view of an estimated position of the mobile station; or (c) satellite almanac information; or (d) an estimated position of the mobile station; or (e) a location of the first wireless access point.

71. The mobile station of claim 61, wherein the mobile station is not authorized to communicate with the first wireless access point by an operator of the first wireless network and is authorized to communicate with the second wireless access point by an operator of the second wireless network.

72. The mobile station of claim 71, wherein the first wireless access point is a first cellular telephone base station, and wherein the second wireless access point is a second cellular telephone base station.

73. The method of claim 61, wherein the range measurements are used to determine the position of the mobile station.

74. The method of claim 61, wherein the first wireless access point and the second wireless access point are both capable of supporting two-way communication with authorized mobile stations.