KR101001007B1 - Position location using broadcast television signals and mobile telephone signals - Google Patents

Abstract

The present invention relates to a method, an apparatus, and a computer readable medium for determining the location of a user terminal, the method comprising:

Receiving a broadcast TV signal from a TV transmitter at a user terminal,

Determine a first pseudo-range between the user terminal and the TV signal transmitter based on the known component of the broadcast TV signal,

-Receive a mobile telephone signal at the user terminal from the mobile telephone base station,

Determine a second pseudo-range between the user terminal and the mobile base station based on the known component of the mobile telephone signal, and

Determine the location of the user terminal based on the first and second pseudo-ranges, the location of the TV signal transmitter, and the location of the mobile telephone base station;

Steps.

Description

POSITION LOCATION USING BROADCAST TELEVISION SIGNALS AND MOBILE TELEPHONE SIGNALS}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to positioning, and relates to positioning using broadcast TV signals and mobile telephone signals.

Methods of two-dimensional latitude and longitude localization systems using radio signals have been proposed for a long time. Terrestrial systems like Loran C and Omegar and satellite based systems called Transit are widely used. Another example of a satellite-based system that is widespread these days is GPS.

GPS was first invented in 1974 and is widely used for positioning, navigation, surveying and time changes. The GPS system is based on a collection of 24 on-orbit satellites with sub-synchronous 12 hour orbits. Each satellite has a precision clock and transmits a pseudo noise signal. This pseudo noise signal can be accurately tracked to determine the pseudo-range. By tracking four or more satellites, the exact location can be determined in three dimensions in real time from any location in the world. Details of this can be found in 1996 at the AIAA in Washington, DC, USA. See Volume I and II of Global Positioning System-Theory and Applications, published by Parkinson and J.J.Spilker Jr.

GPS is revolutionizing navigation and location technology. But GPS is not effective in some situations. Since GPS signals are transmitted over long distances at relatively low power levels (less than 100 watts), the received signal strength is relatively weak (-6 dB level when received by omni-directional antennas). Therefore, GPS signals are not useful when barriers are present or inside buildings.

A system using an existing analog NTSC (National Television System Committee) TV signal for positioning is proposed. This proposal is described in US Patent 5,510,801, "Location Determination System and Method Using Television Broadcast Signals," issued April 23, 1996. However, current analog TV signals have horizontal and vertical synchronization pulses intended for relatively coarse synchronization of the TV set sweep circuit. Moreover, in 2006, the FCC is considering blocking NTSC transmitters and reallocating these critical frequency bands for other useful uses.

1. In general, according to one aspect, the invention features a method, apparatus, and computer readable medium for determining the location of a user terminal. In this method,

Receiving a broadcast TV signal from a TV transmitter at a user terminal,

Determine a first pseudo-range between the user terminal and the TV signal transmitter based on the known component of the broadcast TV signal,

-Receive a mobile telephone signal at the user terminal from the mobile telephone base station,                 

Determine a second pseudo-range between the user terminal and the mobile base station based on the known component of the mobile telephone signal, and

Determine the location of the user terminal based on the first and second pseudo-ranges, the location of the TV signal transmitter, and the location of the mobile telephone base station;

Steps.

Particular implementations may include one or more of the following features. Mobile phone signals are GSM (Global System for Mobile Communications) signals. The known component of the mobile telephone signal is a training sequence. American Television Standards Committee (ATSC) digital TV signals, ETSI (European Telecommunications Standards Institute) DVB-T (Digital Video Broadcasting-Terrestrial) signals, Japanese ISDB-T (Japanese Integrated Services Digital Broadcasting-Terrestrial) signals, and analog TV signals The broadcast TV signal is selected from the group which is comprised. The mobile telephone signal is a code division multiple access (CDMA) signal. A known component of the mobile telephone signal is an unmodulated PN sequence. These implementations

Receiving GPS signals from the GPS satellites at the user's terminal,

Determine a third pseudo-range between the user terminal and the GPS satellites based on the GPS signal, and

Determining the location of the user terminal based on the first, second and third pseudo-ranges, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites.

It may include a step.                 

2. In general, in one aspect, the invention features a method, apparatus, and computer readable medium for determining the location of a user terminal. In this method,

Receiving a broadcast TV signal from a TV transmitter at a user terminal,

Determine a first pseudo-range between the user terminal and the TV signal transmitter based on the known component of the broadcast TV signal,

Receiving at the user terminal a mobile telephone signal from a mobile telephone base station, wherein the mobile telephone signal comprises a range signal;

Determine a range between the user terminal and the mobile base station based on the range signal, and

Determine the location of the user terminal based on the pseudo-range, the range, the location of the TV signal transmitter, and the location of the mobile telephone base station;

Steps.

Particular implementations may include one or more of the following features.

The mobile telephone signal is a Global System for Mobile Communications (GSM) signal, and the range signal includes a timing advance parameter. American Television Standards Committee (ATSC) digital TV signals, ETSI (European Telecommunications Standards Institute) DVB-T (Digital Video Broadcasting-Terrestrial) signals, Japanese ISDB-T (Japanese Integrated Services Digital Broadcasting-Terrestrial) signals, and analog TV signals The broadcast TV signal is selected from the group which is comprised. These implementations                 

Determine a second pseudo-range between the user terminal and the mobile base station based on the known component of the mobile telephone signal, and

Determining the location of the user terminal based on the first and second pseudo-ranges, the range, the location of the TV signal transmitter, and the location of the mobile telephone base station.

It may include a step. The known component of the mobile telephone signal is a training sequence. Implementations of the invention

Receiving GPS signals from the GPS satellites at the user's terminal,

Determine a third pseudo-range between the user terminal and the GPS satellite based on the GPS signal, and

Determining the location of the user terminal based on the first, second and third pseudo-ranges, the range, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites.

It may include a step. Implementations of the invention,

Receiving GPS signals from the GPS satellites at the user's terminal,

Determine a second pseudo-range between the user terminal and the GPS satellite based on the GPS signal, and

Determining the location of the user terminal based on the first and second pseudo-ranges, the range, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites.

It may include a step.                 

3. In general, in one aspect, the invention features a method, apparatus, computer readable medium for determining the location of a user terminal. In this method,

-Receive a broadcast TV signal at a user terminal from a TV signal transmitter,

Determine a first pseudo-range between the user terminal and the TV signal transmitter based on the known component of the broadcast TV signal,

-Receive a mobile telephone signal at the user terminal from the mobile telephone base station,

Determine a second pseudo-range between the user terminal and the mobile base station based on the known component of the mobile telephone signal, and

Transmit the first and second pseudo-ranges to a location server configured to determine the location of the user terminal based on the first and second pseudo-ranges, the location of the TV signal transmitter, and the location of the mobile telephone base station.

Steps.

Particular implementations may include one or more of the following features. Mobile phone signals are GSM (Global System for Mobile Communications) signals. The known component of the mobile telephone signal is a training sequence. American Television Standards Committee (ATSC) digital TV signals, ETSI (European Telecommunications Standards Institute) DVB-T (Digital Video Broadcasting-Terrestrial) signals, Japanese ISDB-T (Japanese Integrated Services Digital Broadcasting-Terrestrial) signals, and analog TV signals The broadcast TV signal is selected from the group which is comprised. The mobile telephone signal is a code division multiple access (CDMA) signal. The known component of the mobile telephone signal is an unmodulated PN sequence. These implementations

Receiving GPS signals from the GPS satellites at the user's terminal,

Determine a third pseudo-range between the user terminal and the GPS satellites based on the GPS signal, and

Said first, second and third location servers configured to determine the location of the user terminal based on the first, second and third pseudo-ranges, the location of the TV signal transmitter, the location of the mobile telephone base station and the location of the GPS satellites; Transmitting pseudo-range

It may include a step.

4. In general, in one aspect, the invention features a method, apparatus, and computer readable medium for determining the location of a user terminal. In this method,

Receiving a broadcast TV signal from a TV transmitter at a user terminal,

Determine a first pseudo-range between the user terminal and the TV signal transmitter based on the known component of the broadcast TV signal,

Receiving at the user terminal a mobile telephone signal from a mobile telephone base station, wherein the mobile telephone signal comprises a range signal;

Determine a range between the user terminal and the mobile base station based on the range signal, and

Transmit the pseudo-range and the range to a location server configured to determine the location of the user terminal based on the pseudo-range, the range, the location of the TV signal transmitter, and the location of the mobile telephone base station.                 

Steps.

Particular implementations may include one or more of the following features.

The mobile telephone signal is a Global System for Mobile Communications (GSM) signal, and the range signal includes a timing advance parameter. American Television Standards Committee (ATSC) digital TV signals, ETSI (European Telecommunications Standards Institute) DVB-T (Digital Video Broadcasting-Terrestrial) signals, Japanese ISDB-T (Japanese Integrated Services Digital Broadcasting-Terrestrial) signals, and analog TV signals The broadcast TV signal is selected from the group which is comprised. These implementations

Determine a second pseudo-range between the user terminal and the mobile base station based on the known component of the mobile telephone signal, and

The first and second pseudo-ranges and the ranges to a location server configured to determine the location of the user terminal based on the first and second pseudo-ranges, the ranges, the location of the TV signal transmitter, and the location of the mobile telephone base station. To send

It may include a step. The known component of the mobile telephone signal is a training sequence. Implementations of the invention,

Receiving GPS signals from the GPS satellites at the user's terminal,

Determine a third pseudo-range between the user terminal and the GPS satellite based on the GPS signal, and

The location server configured to determine the location of the user terminal based on the first, second, third pseudo-range, the range, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites. 1, 2, 3 pseudo-ranges and transmitting the ranges,

It may include a step. Implementations of the invention,

Receiving GPS signals from the GPS satellites at the user's terminal,

Determine a second pseudo-range between the user terminal and the GPS satellite based on the GPS signal, and

Said first and second location servers configured to determine a location of a user terminal based on said first and second pseudo-ranges, said range, the location of a TV signal transmitter, the location of a mobile telephone base station, and the location of a GPS satellite. Pseudo-range and transmitting the range

It may include a step.

5. In general, in one aspect, the invention features a method, apparatus, and computer readable medium for determining the location of a user terminal. In this method,

Receive a first pseudo-range from the user terminal, wherein the first pseudo-range is determined between the user terminal and the TV signal transmitter based on a known component of the broadcast TV signal transmitted by the TV signal transmitter,

Receive a second pseudo-range from the user terminal, wherein the second pseudo-range is determined between the user terminal and the mobile base station based on a known component of the mobile telephone signal transmitted by the mobile telephone base station, and

Determine the location of the user terminal based on the first and second pseudo-ranges, the location of the TV signal transmitter, and the location of the mobile telephone base station.

Steps. Mobile phone signals are GSM (Global System for Mobile Communications) signals. The known component of the mobile telephone signal is a training sequence. American Television Standards Committee (ATSC) digital TV signals, ETSI (European Telecommunications Standards Institute) DVB-T (Digital Video Broadcasting-Terrestrial) signals, Japanese ISDB-T (Japanese Integrated Services Digital Broadcasting-Terrestrial) signals, and analog TV signals The broadcast TV signal is selected from the group which is comprised. The mobile telephone signal is a code division multiple access (CDMA) signal. A known component of the mobile telephone signal is an unmodulated PN sequence. These implementations

Receive a third pseudo-range between the user terminal and the GPS satellite based on the GPS signal transmitted by the GPS satellite, and

Determining the location of the user terminal based on the first, second and third pseudo-ranges, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites.

It may include a step.

6. In general, in one aspect, the invention features a method, apparatus, and computer readable medium for determining the location of a user terminal. In this method,

Receive a pseudo-range between the user terminal and the TV signal transmitter, wherein the pseudo-range is determined based on known components of the broadcast TV signal transmitted by the TV transmitter,                 

Receive a range between the user terminal and the mobile telephone base station, wherein the range is determined based on a range signal transmitted by the mobile telephone base station, and

Determine the location of the user terminal based on the pseudo-range, the range, the location of the TV signal transmitter, and the location of the mobile telephone base station;

Steps. The mobile telephone signal is a Global System for Mobile Communications (GSM) signal, and the range signal includes a timing advance parameter. American Television Standards Committee (ATSC) digital TV signals, ETSI (European Telecommunications Standards Institute) DVB-T (Digital Video Broadcasting-Terrestrial) signals, Japanese ISDB-T (Japanese Integrated Services Digital Broadcasting-Terrestrial) signals, and analog TV signals The broadcast TV signal is selected from the group which is comprised. These implementations

Receive a second pseudo-range between the user terminal and the mobile telephone base station, wherein the second pseudo-range is determined based on a known component of the mobile telephone signal, and

Determining the location of the user terminal based on the first and second pseudo-ranges, the range, the location of the TV signal transmitter, and the location of the mobile telephone base station.

It may include a step. The known component of the mobile telephone signal is a training sequence. Implementations of the invention

Receive a third pseudo-range between the user terminal and the GPS satellites, wherein the third pseudo-range is determined based on a GPS signal transmitted by the GPS satellites, and

Determining the location of the user terminal based on the first, second and third pseudo-ranges, the range, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites.

It may include a step. Implementations of the invention,

Receive a second pseudo-range between the user terminal and the GPS satellites, wherein the second pseudo-range is determined based on a GPS signal transmitted by the GPS satellites, and

Determining the location of the user terminal based on the first and second pseudo-ranges, the range, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites.

It may include a step.

1 is an embodiment of the present invention including a user terminal in communication with a base station over an air link.

2 is an operational diagram of one embodiment of the invention.

3 is a diagram of position determination using three DTV transmitters.

4 is a format diagram of a normal burst of a GSM signal.

5 is a format diagram of a SACCH channel.                 

6 is a system architecture diagram showing only two DTV transmitters with good arrangement and one GSM base station for a user terminal.

7 is a diagram of a location solution using GSM timing advance without further modification, with measurements of two DTV signals.

8 is a simplified diagram of a time-gate delay lock loop used to measure pseudo-range by comparing the measured synchronization time with a local reference clock of a user terminal in one embodiment.

Introduction

The broadcast TV signal may be used to determine the location of the user terminal. A technique for positioning a user terminal using ATSC DTV signals is described in James J. Spilker and Matthew Rabinowitz, US Patent Application No. 09 / 887,158, "Position Location Using Broadcast Digital Television Signals," issued June 21, 2001. Incorporated herein by reference. Techniques for user terminal positioning using ETSI DVB-T signals are described in James J. Spilker and Matthew Rabinowitz, US Patent Application No. 09 / 887,158, entitled "Position Location Using Terrestrial Digital Video Broadcast Television Signals," published August 17, 2001. The contents of which are incorporated herein by reference. The technique of positioning user terminals using Japanese ISDB-T signals is described in James J. Spilker and Matthew Rabinowitz, US Patent Application No. 60 / 337,834, "Wireless Position Location Using the Japanese ISDB-T Signals," dated November 9, 2001. The contents of which are incorporated herein by reference. A user terminal position determination technique using NTSC analog TV signal is described in James J. Spilker, US Patent Application No. 10 / 054,302, January 22, 2002, "Position Location Using Broadcast Analog Television Signals", the contents of which are described herein. It is cited for reference. It is also introduced by James J. Spilker and Matthew Rabinowitz in "Position Location Using Ghost Canceling Reference Television Signals" (TBS, Attorney Docket Number RSM 008001), the contents of which are hereby incorporated by reference.

Each of these TV signals includes components that can be used to obtain a pseudo-range for the TV signal transmitter. Knowing several such pseudo-ranges and knowing transmitter positions, it is possible to accurately determine the user terminal position. Appropriate components in an ATSC digital TV signal include synchronization codes such as field synchronization segments in ATSC data frames and synchronization segments in data segments in ATSC data frames. Suitable components in ETSI DVB-T and ISDB-T digital TV signals include scattered pilot carriers. Suitable components of the NTSC analog TV signal include a horizontal synchronization pulse, a horizontal blanking pulse, a combination of a horizontal blanking pulse and a horizontal synchronization pulse, a ghost canceling reference signal, and a vertical interval test signal.

In most urban areas there is a sufficient number of TV signal broadcasts from different locations, so that pseudo-ranges can be measured from three or more angles to determine the location of the user terminal. In some areas, however, hills, buildings, other obstructions, and even human bodies can block one of the TV signals. Alternatively, the user terminal may be located in a rural area far from the required number of TV transmitters. In such a case, the signal transmitted by the mobile telephone base station may be used to provide the remaining pseudo-range. In addition, these pseudo-ranges may be augmented using ranges derived from range signals transmitted by the mobile telephone base station, such as GSM timing advance parameters. Positioning techniques using broadcast TV signals and signals transmitted from mobile base stations are described in James J. Spilker Jr., US Patent Application No. 60 / 315,983, filed August 29, 2001, "Digital Television Position Location Aided by GSM Measurements", Jimmy. U.S. Patent Application No. 60 / 329,592, filed October 15, 2001, K. Omura, "Digital Television Position Location Aided by CDMA Measurements," US Patent Application No. 60 / 378,819, May 7, 2002, of Jimmy, K. Omura, "Combining E. -OTD with a TV Based Cell Phone Position Location System, the contents of which are incorporated herein by reference. Using this technique, a user terminal can determine its location using a combination of broadcast TV signals and mobile phone base station signals. In various embodiments, mobile phone signals used include GSM signals and CDMA signals.

Additional pseudo-ranges may be provided using standard GPS receivers. Techniques for improving positioning using broadcast TV signals in conjunction with GPS signals are described in James J. Spilker Jr., US Patent Application No. 60 / 361,762, "DTV Position Location Augmented by GPS," issued March 4, 2002, The disclosure is incorporated herein by reference. A user terminal using these techniques can determine its location using a combination of broadcast TV signal, mobile phone base station signal, and GPS signal.

See FIG. 1. The first embodiment 100 includes a user terminal 102 in communication with a base station 104 using an air link. In some implementations, user terminal 102 is a wireless telephone and base station 104 is a wireless telephone base station. In some implementations, the base station 104 is part of a mobile metropolitan area network (MAN) or wide area network (WAN).

1 is used to illustrate various aspects of the invention, but the invention is not limited to this implementation. For example, the term "user terminal" refers to any object that can implement the location technology described herein. Examples of user terminals include PDAs, mobile phones, vehicles and other vehicles, and any object that may include a chip or software that implements the positioning techniques introduced herein. Moreover, the term "user terminal" is not limited to objects that are "terminals" and objects that are operated by "users."

2 illustrates one implementation operation 100. The user terminal 102 receives a broadcast signal from one or more TV transmitters 106A, 106B- 106N (step 202). In FIG. 1, the TV transmitter 106A is an ETSI transmitter, the TV transmitter 106B is an NTSC transmitter, and the TV transmitter 106N is an ATSC transmitter. Other combinations, including Japanese ISDB signal transmitters, may of course be considered.

Several methods can be used as to which TV channel to select for use in positioning. In one implementation, location server 110 tells user terminal 102 the best TV channel to monitor. In some implementations, user terminal 102 uses base station 104 to exchange messages with location server 110. In some implementations, user terminal 102 selects a TV channel to monitor based on the identity of base station 104 and a storage table that correlates the base station and TV channels. In some implementations, user terminal 102 may receive input from a user that provides a general indication of the user terminal location (eg, the closest city name) and may use this information to select a TV channel to process. . In some implementations, the user terminal 102 scans the available TV channels to combine fingerprints of the location based on the power level of the available TV channels. The user terminal 102 selects a TV channel for processing by comparing the fingerprint to a storage table that matches a known fingerprint with a known location.

User terminal 102 determines a pseudo-range between the user terminal and each TV transmitter 106 (step 204). Each pseudo-range comprises a time difference (or equivalent distance) between the transmission time from the transmitter 106 of one component of the TV broadcast signal and the reception time of the component at the user terminal 102, and at the user terminal. Indicates the clock offset.

User terminal 102 transmits a pseudo-range to location server 110. In some implementations, location server 110 is implemented as a general purpose computer running software designed to carry out the operations described herein. In another implementation, the location server is implemented as an ASIC or some other kind of device. In some implementations, location server 110 is implemented in or near base station 104.

The TV signal is also received by multiple monitor units 108A-N. Each monitor unit 108 may be implemented as a small unit including a transceiver and a processor and may be mounted at a convenient location, such as at a utility pole, TV transmitter 106, or base station 104. In some implementations, monitor unit 108 is implemented on a satellite.

Each monitor unit 108 measures, for each TV transmitter 106 that transmits a TV signal, a time offset between the local clock and the reference clock of the TV transmitter. In some implementations, the reference clock is derived from the GPS signal. By using the reference clock, when several monitor units 108 are used, it is possible to determine the time offset for each TV transmitter 106. This is because each monitor unit 108 can determine a time offset relative to the reference clock. Thus, the offset of the local clocks of the monitor unit 108 does not affect this determination. The monitor unit 108 is described in detail in US Patent Applications 09 / 887,158, 09 / 932,010, and 10 / 054,302. The contents of which are incorporated herein by reference.

Another implementation does not require any external time reference. According to this implementation, a single monitor unit 108 receives TV signals from all of the same TV transmitters as in the user terminal 102. As a result, the local clock of a single monitor unit functions as a time reference.

In some implementations, each time offset is modeled as a fixed offset. In another implementation, each time offset is modeled as a quadratic polynomial of the form                 

Offset = a + b (tT) + c (tT) ² (1)

That is, it can be described by a, b, c, and T. In any implementation, each measured time offset is periodically sent to the location server by the Internet, a secure modem connection, or the like. In some implementations, the location of each monitor unit 108 is determined using a GPS receiver.

Location server 110 receives information from database 112 that describes the phase center (ie, location) of each TV transmitter 106. In some implementations, the phase center of each TV transmitter 106 is measured by using the monitor unit 108 in several different positions to accurately measure the phase center. In another implementation, the phase center of each TV transmitter 106 is measured by examining the antenna phase center.

In some implementations, location server 110 receives weather information from weather server 114 that describes the ambient temperature, atmospheric pressure, and humidity near the user terminal. Weather information is also available from the Internet and from other sources such as NOAA. Location server 110 is described in B. Parkinson and J. Spilker Jr.'s Global Positioning System-Theory and Applications (AIAA, 1996, Washington, DC). The tropospheric propagation velocity is determined from meteorological information using techniques such as those introduced in Tropospheric Effects on GPS by J. Spilker Jr. in Chapter 17.

Location server 110 may also receive from base station 104 information identifying a general geographic location of user terminal 102. For example, this information can identify the cell or cell sector where the cellular telephone is located. This information is used to resolve ambiguities.

User terminal 102 receives a mobile telephone signal from one or more mobile telephone base stations 104 (step 206). The mobile phone signal may include a range signal such as a GSM timing advance parameter. The user terminal 102 determines a range or pseudo-range between the user terminal 102 and each mobile telephone base station 104 (step 208). This range can be obtained from the range signal. Each pseudo-range comprises a time difference (or equivalent distance) between the transmission time from the mobile telephone base station 104 of one component of the mobile telephone signal and the reception time at the user terminal 102 of the one component, and the movement. Indicates the clock offset at the telephone base station. User terminal 102 sends this pseudo-range to the location server.

Location server 110 determines the location of the user terminal based on the pseudo-range, range, location of each TV transmitter 106, and location of mobile phone base station 104 (step 210). 3 shows a location determination structure using three transmitters 302. The transmitters 302 can include any combination of a TV transmitter and a mobile telephone base station. Transmitter 302A is located at positions x1, y1, z1. The range between the user terminal 102 and the transmitter 302A is r1. Transmitter 302B is located at locations x2, y2, z2 and the range between user terminal 102 and transmitter 302B is r2. The transmitter 302N is located at locations x3, y3, z3 and the range between the user terminal 102 and the transmitter 302N is r3.                 

The location server 110 may adjust each pseudo-range value according to the time offset and tropospheric propagation speed for the transmitter 302 in question. The location server 110 uses the phase center information from the database 112 to determine the location of each transmitter 302. The location of the GSM base station and its clock offset can be obtained from the E-OTD cooperative data broadcast message transmitted by the GSM base station.

The user terminal 102 makes three or more pseudo-range measurements to find three unknown values: the position (x, y) and the clock offset T of the user terminal 102. The altitude (ie, height) of the user terminal is known to be within the required level of accuracy and assumes that only the longitude and latitude of the user terminal need be accurately determined. Of course, assuming that four or more transmitters are available and that the arrangement of these transmitters is sufficient, the position of the user terminal can be determined in three dimensions, that is, (x, y, z). Adjusting the techniques introduced here for three-dimensional position fixation is clear to those of ordinary skill in the art.

Three pseudo-range measurements pr1, pr2 and pr3 are given by

pr1 = r1 + T (2)

pr2 = r2 + T (3)

pr3 = r3 + T (4)

The three ranges can be expressed as

r1 = | X-X1 | (5)

r2 = | X-X2 | (6)

r3 = | X-X3 | (7)                 

Where X is the three-dimensional vector position (x, y, z) of the user terminal, X1 is the three-dimensional vector position (x1, y1, z1) of the transmitter 302A, and X2 is the three-dimensional vector of the transmitter 302B. Position (x2, y2, z2) and X3 represent the three-dimensional vector position (x3, y3, z3) of transmitter 302N. These relationships produce three equations for solving the unknowns x, y, and T. If only longitude and latitude are needed, assume that location server 110 assumes some estimate of z and cannot obtain its value for the remaining unknown coordinates. In one implementation, using the topographic map, the initial estimate of z may be iteratively redefined based on the computed values for x and y. In another implementation, location server 110 actively resolves z. Location server 110 solves these equations according to known conventional methods. In an E911 application, the location of the user terminal 102 is sent to the E911 location server 116 for distribution to the appropriate authorities. In another application, the location is sent to the user terminal 102.

In some implementations, user terminal 102 does not compute pseudo-ranges, but instead takes measurements of signals sufficient to compute pseudo-ranges and transmits these measurements to location server 110. The location server 110 calculates a pseudo-range based on the measurement and calculates a position based on the pseudo-range (as described above).

Determine location executed by user terminal

In some implementations, the user terminal 102 location is computed by the user terminal 102. In this implementation, all necessary information is sent to the user terminal 102. This information may be transmitted to the user terminal 102 by the location server 110, the base station 104, one or more TV transmitters 106, the mobile telephone base station 104, or a combination thereof. The user terminal 102 then measures the pseudo-range to solve the equations as described above. This implementation is now described.

The user terminal 102 receives a time offset between the local clock and reference clock of each TV transmitter 106. User terminal 102 also receives information describing the center of phase of each TV transmitter 106 from database 112.

The user terminal 102 receives the tropospheric propagation speed calculated by the location server 110. In some implementations, the user terminal 102 receives weather information from the weather server 114 describing the atmospheric temperature, atmospheric pressure, and humidity near the user terminal 102 and uses existing techniques to provide tropospheric propagation rates from the weather server. Determine.

The user terminal 102 may also receive information identifying the schematic location of the user terminal 102 from the base station 104. For example, this information can identify the cell or cell sector where the cellular telephone is located. This information is used to resolve ambiguities.

The user terminal 102 receives TV signals from one or more TV transmitters 106 and determines the pseudo-range between the user terminal 102 and each TV transmitter 106. The user terminal 102 receives mobile telephone signals from one or more mobile telephone base stations 104 to determine pseudo-ranges or ranges between the user terminal 102 and the mobile telephone base station 104. The user terminal 102 then determines the user terminal location based on the pseudo-range or range, the TV transmitter 106 location, and the mobile telephone base station 104 location.

In any of these implementations, the user terminal 102 position can be computed using a TV transmitter, and the offset T during pre-positioning for the TV transmitter can be computed. The T value can be stored or managed according to existing methods.

In some implementations, base station 104 determines the clock offset of user terminal 102. In this implementation, only two transmitters are needed for position determination. Base station 104 transmits clock offset T to location server 110 and determines the location of user terminal 102 from the pseudo-range computed for each transmitter.

Location using GSM mobile phone signal

The GSM mobile phone signal is a frequency division multiple access / time division multiple access (FDMA / TDMA) signal with a 200 kHz bandwidth and a bit rate of 1525/6 = 270.83333 kbps. The GSM signal has a 200 kHz guard band and 124 200 kHz frequency channels for a total bandwidth of 25 MHz for transmission and 25 MHz for reception. Each frequency channel is modulated by a 270.8333 kbps Gaussian minimum shift key signal with one TDMA frame divided into eight time slots shared by eight different active users. Thus the system has a capacity of 8 x 124 = 992 time slots. A pair of frequency channels spaced by 45 MHz is assigned to a given duplex channel.

The GSM signal has five burst formats: normal burst, frequency correction burst, synchronization burst, dummy burst, and access burst. The frequency calibration burst has a pure carrier component for close to six tail bit plus guard times. Because of the 0.3 GMSK modulation, a stream of "0" bits generates a pure carrier with a frequency shift of 1625/24 kHz = 67.7+ kHz over the nominal carrier frequency. This pure carrier is used by the user terminal to calibrate the local crystal oscillator. Synchronization bursts are used for timing with 64-bit training sequences instead of normal 26-bit training sequences. The dummy burst is the same as the normal burst except that there is no data. The access burst has a much larger 68.25 guard space, a 41-bit training sequence, and only 36 data bits.

The format for normal bursts is shown in FIG. This format includes three tail bits 402, 67 data bits 404, a 26-bit synchronous training sequence 406, 57 data bits 408, three tail bits 410, and 8.25 guard bits 412. ).

These various burst format training sequences are known bit patterns used by embodiments of the present invention for timing synchronization. There are eight training sequences for normal burst transmission, indicated by base station color codes. The training sequence is used to adjust the adaptive equalizer and correct the propagation delay.

The user terminal enters the system by making a request for one of the random access channels. However, for TDMA signals with eight bursts per TDMA frame to work properly, user terminals located at different distances from the base station must transmit TDMA bursts at different time offsets. This allows TDMA bursts to be received at base stations at appropriate timing without duplication between bursts.

To this end, the base station transmits a range signal including timing advance parameters. Of course, if other range signals are available, they can be used instead. The timing advance parameter has 64 steps per data bit, corresponding to twice the one-way propagation time. Thus, each increment is in the range of 1.846 microseconds or 1846 feet for free space propagation. The timing advance parameter thus provides itself with a range accuracy of approximately +/- 307.6 yards or 302.7 meters from the base station to the user terminal. Although this accuracy is not as accurate as desired, it is already available at the user terminal and, when combined with the high accuracy of the TV signal measurements, yields acceptable results in the outer region where only two TV signals with good alignment appear.

The timing advance parameters are transmitted on one of the signaling channels used for GSM. There are three dedicated control channels (DCCHs) in the signaling channel set. One of these DCCH channels is a slow associated control channel (SACCH) that is bidirectional (between a user terminal and a base station) and contains 7-bit timing advance information. The format of the SACCH channel is shown in FIG. This link control parameter is measured and updated every 480 milliseconds.

6 shows a system architecture in which only two DTV transmitters 106 are shown in a good arrangement, and with only one GSM base station 104 for the user terminal 102. Of course, if additional GSM base station 104 is visible, the signals can be used to improve the accuracy of the location.

Signals are relayed from the user terminal 102 to the location server 110 by the GSM base station transceiver system (BTS) 104, the base station controller (BSC) 602, and the mobile switching center 604.

GSM system measurements may take one of several forms. One embodiment uses a normal GSM timing advance parameter, which is always provided. Accuracy is not as good as desired. However, no additions to normal GSM operation, except that timing advance is also supplied to location server 110 along with other DTV signal measurements, such as using one or more GSM Short Message Service (SMS) messages. It is not necessary. Location server 110 integrates timing advance measurements with location information of base station 104 to know the location of user terminal 102.

Another embodiment measures the pseudo-range between the user terminal 102 and the base station 104 and uses this pseudo-range together with the pseudo-range between the user terminal 102 and the DTV transmitter 106 to determine the user's terminal. Find the location very accurately. This embodiment includes a pseudo-range delay lock loop that operates on a GSM training sequence. The training sequence for normal bursts does not have a 100% duty factor, but instead has a duty factor of 26 / (156.25 x 8) = 2.08%. Nevertheless, for one second average time, the GSM normal burst training sequence has a processing gain of 270,833 X 0.0208 = 5633 or 37.5 dB. Of course, training sequences in other kinds of GSM bursts may also be used.

Other embodiments use one or more timing advance parameters and one or more pseudo-ranges between the user terminal 102 and the base station 104 in addition to the pseudo-ranges between the user terminal 102 and the DTV transmitter 106. .

7 shows a location solution using GSM timing advance without further modification, with measurements of two DTV signals. In this simple example, the GSM timing advance provides a trace of the solution, which is an arc 702 of radius corresponding to a timing advance of luminous flux times nanoseconds in the atmosphere. The angular width of arc 702 corresponds to the angular range of the k-sector antenna, and with eight sectors the angular width is 360/8 = 45 degrees. Two DTV solutions simply provide a hyperbola 704 corresponding to the delay difference. The position solution is the intersection 706 of the arc 702 and the appropriate hyperbolic 704.

8 is a simplified configuration diagram of a time-gate delay lock loop (TGDLL) receiver 800 used to measure pseudo-range by comparing the measured synchronization time with a local reference clock of the user terminal in one embodiment. . Time-gate DLLs (Delayed Lock Loops) are described in James J. Spilker and Matthew Rabinowitz, January 22, 2002, US Patent Application No. 10 / 054,262, "Time-Gated Delay Lock Loop Tracking of Digital Television Signals." The contents are incorporated herein by reference.

Although FIG. 8 shows a non-coherent delay lock loop, it should be understood that a coherent time-gate delay lock loop may of course be used. Since the GSM receiver must operate coherently, the signal level and clock recovery are sufficient to operate the DLL in coherent mode.

The time-gate controller 802 generates time-gate signals that turn on and off the memoryless elements of the receiver 800 to conserve power, so that these elements operate and generate signals only when they are needed. The time-gate controller 802 is controlled by a timing signal generated by the local clock 804 based on the timing of the training sequence. Elements of the front end of the receiver can of course also be time-gated. This saves substantial power, enabling a particularly suitable implementation for portable devices with limited power resources.

The received GSM signal is passed by a switch 806 which is also controlled by the time gate controller 802 to reach a pair of mixers 808A and 808B. In this mixer, the signal is mixed into I and Q samples of the training sequence. These samples are provided by the training sequence generator 810. The output of the mixer 808 is filtered by the intermediate frequency filters 812A, 812B and then drives the non-coherent detector (NCD) 814A, 814B. The outputs of NCD 814 are combined by summer 816 and filtered by DLL loop filter 818. The output of the filter 818 drives the numerically controlled oscillator (NCO) 820 driven by the local clock 804 and the training sequence generator 810.

The TGDLL 800 may use not only the 26-bit training sequence of the GSM normal burst but also various control signals broadcast from the GSM base station 104 and other GSM burst training sequences. These different approaches allow for more accurate measurements than those obtained using only timing advance parameters.

The location processor 110 also addresses the location of the sector and base station antennas used by the user terminal. In addition, the clock timing of the base station must be known. This is easily accomplished when the base station clock is synchronized to GPS or other timing sources, and the distance from the clock to the antenna is calculated or measured.

Either of these approaches, using only timing advance parameters or measuring pseudo-ranges for GSM base stations, can be located when there are only two DTV towers in a good configuration. Of course, if more base stations or DTV towers appear, additional performance improvements can be obtained.

Location using CDMA mobile phone signal

One of the most widely used digital cellular systems today is based on the US IS-95 CDMA standard. CDMA cellular systems use spread spectrum signals that are robust against interference and multipath. This robustness to interference allows all CDMA cell sites to use the same transmit and receive frequency bands. To minimize inter-site interference, each CDMA base station signal uses a spread-spectrum transmit signal based on a pseudo noise (PN) bit sequence generated by a linear feedback generator, where an in-phase generator is used. Is represented by the following polynomial:

f _I (x) = 1 + x ² + x ⁶ + x ⁷ + x ⁸ + x ¹⁰ + x ¹⁵ (8)

The quadrature generator is represented by the following polynomial.

f _Q (x) = 1 + x ³ + x ⁴ + x ⁵ + x ⁹ + x ¹⁰ + x ¹¹ + x ¹² + x ¹⁵ (9)

These are the maximum length shift register sequences with period 215-1, 32,767.                 

All CDMA base station signals use this same in-phase and quadrature PN sequence. These sequences of modulating carriers behave like high-level carriers where data is modulated. The chip rate for each signal is 1.2288 Mcps. Each period of this sequence is repeated every 26.66 milliseconds, or 75 times every two seconds.

In order to minimize interference at the user terminal from several different cell site transmissions using the same frequency band, each cell site PN sequence is offset by an integer multiple of 64 chips. There are 512 unique offsets. All base stations within a region use different offsets to minimize interference and help user terminal acquisition of the strongest base station signal. This method of using offsets of the same sequence in a transmission signal requires that all base stations maintain a stable time reference that allows time synchronization of the transmitters. All CDMA cell sites get their own time reference with the GPS receiver.

The IS-95 digital cellular system operates in the same band as the current analog cellular band (AMPS), in which frequency division duplexing of 25 MHz in each direction, the uplink band of 869-894 MHz (user terminal-> base station) And full duplex operation using the downlink band (base station-> user terminal) of 824-849 MHz. The 25 MHz band for each direction is divided into 20 bands, with each band of 1.25 MHz using a single carrier with a PN sequence of in-phase and quadrature components with a chip rate of 1.2288 Mcps.

Each downlink signal in the 1.25 MHz band has 64 channels, including one high power pilot channel, one low power synchronization channel, and 62 paging and traffic channels. The pilot channel allows the user terminal to capture and track base station signals. The user terminal captures the strongest of these unmodulated pilot channel signals from the different base stations it finds by being arranged for every offset time shift of the PN sequence. Using the synchronization channel, the user terminal can perform time synchronization for the selected base station network. Each of these downlink channels uses one of the 64 orthogonal Walsh codewords to separate the channels using the same 1.25 MHz band. The user terminal receives from one of these base station channels using one of the 64 Walsh codewords.

The pilot channel is the highest output channel, using all zero Walsh codewords, which means that this signal is an unmodulated PN sequence. This pilot channel is orthogonal to all other channels when cross correlation is made over the time interval of the 64-bit Walsh codeword. To obtain pseudo-range measurements, the TGDLL 800 of FIG. 8 may be implemented at the user terminal 102, where the training sequence generator generates an unmodulated PN sequence.

Alternative embodiment

The invention can be implemented in digital telephone circuitry, or in computer hardware, firmware, software, or a combination thereof. The apparatus of the invention may be embodied as a computer program product tangibly embodied in a machine-readable storage device for execution by a programmable processor. The methods of the invention can be executed by a programmable processor executing a program of instructions to carry out the functions of the invention by operating on input data and generating output. The invention is practiced in a programmable system comprising a data storage system, one or more input devices, and one or more programmable processors coupled to receive data and commands from and send data and commands to one or more output devices. It may be implemented in more than one computer program. Each computer program may be implemented in a high-level procedural or object-oriented programming language and may be implemented in assemblies or gears as necessary. In any case, the language can be a compiled language or an interpreted language. Suitable processors include, for example, general purpose microprocessors and dedicated microprocessors. In general, a processor will receive instructions and data from a ROM or RAM. Generally, a computer will include one or more approximate storage devices for storing data files. Examples of such devices include magnetic disks such as internal hard disks and removable disks, magneto-optical disks, and optical disks. Suitable storage devices for shaping computer program instructions and data into types include all types of nonvolatile memory, such as EPROMs, EEPROMs, flash memory devices, magnetic disks such as internal hard disks or removable disks, magneto-optical disks, and CD- ROM. Any of the above can be supplemented by an ASIC or integrated into the ASCI.

A number of embodiments of the invention have been described. Nevertheless, various modifications may be made without departing from the scope and spirit of the invention.                 

For example, many different signals and signal processing techniques are described herein in analog form, but a digital implementation will become apparent after reading this specification to those skilled in the art.

In some implementations, location server 110 may make additional verifications to validate each TV channel and pseudo-range using redundant signals available at the system level, such as pseudo-range available from the TV transmitter. The wrong TV channel can be identified. One such technique is conventional Receiver Autonomous Integrity Monitoring (RAIM).

Claims (192)

A method for determining the location of a user terminal, the method comprising: -Receive a broadcast TV signal at a user terminal from a TV signal transmitter, Determine a first pseudo-range between the TV signal transmitter and the user terminal based on the known component of the broadcast TV signal, -Receive a mobile telephone signal at the user terminal from the mobile telephone base station, Determine a second pseudo-range between the mobile telephone base station and the user terminal based on the known component of the mobile telephone signal, and Determine the location of the user terminal based on the first and second pseudo-ranges, the location of the TV signal transmitter, and the location of the mobile telephone base station; And determining the location of the user terminal. 2. The method of claim 1 wherein the mobile telephone signal is a GSM signal. 3. The method of claim 2, wherein the known component of the mobile phone signal is a training sequence. 4. The method of claim 3, wherein the broadcast TV signal is selected from the following signals. -ATSC digital TV signal, ETSI DVB-T signal, Japanese ISDB-T signal, and -Analog TV signal. The method of claim 1, wherein said mobile telephone signal is a CDMA signal. 6. The method of claim 5, wherein the known component of the mobile telephone signal is an unmodulated PN sequence. 7. The method of claim 6, wherein the broadcast TV signal is selected from the following signals. -ATSC digital TV signal, ETSI DVB-T signal, Japanese ISDB-T signal, and -Analog TV signal. The method of claim 1, wherein the method is Receiving GPS signals from the GPS satellites at the user's terminal, The GPS satellite and the user terminal determine a third pseudo-range based on the GPS signal, and Determining the location of the user terminal based on the first, second and third pseudo-ranges, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites. And determining the location of the user terminal. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete A computer readable medium embodying instructions executed by a computer to execute a method for determining a location of a user terminal, the method comprising: -Receive a broadcast TV signal at a user terminal from a TV signal transmitter, Determine a first pseudo-range between the TV signal transmitter and the user terminal based on the known component of the broadcast TV signal, -Receive a mobile telephone signal at the user terminal from the mobile telephone base station, Determine a second pseudo-range between the mobile telephone base station and the user terminal based on the known component of the mobile telephone signal, and Determine the location of the user terminal based on the first and second pseudo-ranges, the location of the TV signal transmitter, and the location of the mobile telephone base station; Computer-readable media, comprising the steps of: 50. The computer readable medium of claim 49, wherein said mobile phone signal is a GSM signal. 51. The computer readable medium of claim 50, wherein the known component of the mobile telephone signal is a training sequence. 53. The computer readable medium of claim 51, wherein the broadcast TV signal is selected from the following signals. -ATSC digital TV signal, ETSI DVB-T signal, Japanese ISDB-T signal, and -Analog TV signal. 50. The computer readable medium of claim 49, wherein said mobile phone signal is a CDMA signal. 54. The computer readable medium of claim 53, wherein the known component of the mobile telephone signal is an unmodulated PN sequence. 55. The computer readable medium of claim 54, wherein the broadcast TV signal is selected from the following signals. -ATSC digital TV signal, ETSI DVB-T signal, Japanese ISDB-T signal, and -Analog TV signal. The method of claim 49, wherein the method comprises Receiving GPS signals from the GPS satellites at the user's terminal, The GPS satellite and the user terminal determine a third pseudo-range based on the GPS signal, and Determining the location of the user terminal based on the first, second and third pseudo-ranges, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites. Computer-readable media, comprising the steps of: delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete A device for determining the location of a user terminal, the device comprising: A receiver for receiving a broadcast TV signal at a user terminal from a TV signal transmitter, and A processor for determining a first pseudo-range between the TV signal transmitter and the user terminal based on the known component of the broadcast TV signal Including, wherein The receiver receives a mobile telephone signal from a mobile telephone base station at a user terminal, The processor determines a second pseudo-range between the mobile telephone base station and the user terminal based on a known component of the mobile telephone signal, and And the processor determines the position of the user terminal based on the first and second pseudo-ranges, the position of the TV signal transmitter, and the position of the mobile telephone base station. 100. The apparatus of claim 97, wherein the mobile telephone signal is a GSM signal. 99. The apparatus of claim 98, wherein the known component of the mobile phone signal is a training sequence. The apparatus of claim 99, wherein the broadcast TV signal is selected from the following signals. -ATSC digital TV signal, ETSI DVB-T signal, Japanese ISDB-T signal, and -Analog TV signal. 98. The apparatus of claim 97, wherein the mobile telephone signal is a CDMA signal. 102. The apparatus of claim 101, wherein the known component of the mobile telephone signal is an unmodulated PN sequence. 103. The apparatus of claim 102, wherein the broadcast TV signal is selected from the following signals. -ATSC digital TV signal, ETSI DVB-T signal, Japanese ISDB-T signal, and -Analog TV signal. 97. The method of claim 97, The receiver receives a GPS signal at the user terminal from a GPS satellite, The processor determines a third pseudo-range by a GPS satellite and a user terminal based on the GPS signal, and The processor determines the location of the user terminal based on the first, second, third pseudo-range, the location of the TV signal transmitter, the location of the mobile telephone base station, and the location of the GPS satellites. Device for positioning a user terminal, characterized in that. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete A device for determining the location of a user terminal, the device comprising: Receiver means for receiving a broadcast TV signal at a user terminal from a TV signal transmitter, and Processor means for determining a first pseudo-range between the TV signal transmitter and the user terminal based on a known component of the broadcast TV signal Including, wherein The receiver means receives a mobile telephone signal at a user terminal from a mobile telephone base station, The processor means determines a second pseudo-range between the mobile telephone base station and the user terminal based on a known component of the mobile telephone signal, and And the processor means determines the position of the user terminal based on the first and second pseudo-ranges, the position of the TV signal transmitter, and the position of the mobile telephone base station. 145. The apparatus of claim 145, wherein the mobile phone signal is a GSM signal. 148. The apparatus of claim 146, wherein the known component of the mobile telephone signal is a training sequence. 148. The apparatus of claim 147, wherein the broadcast TV signal is selected from the following signals. -ATSC digital TV signal, ETSI DVB-T signal, Japanese ISDB-T signal, and -Analog TV signal. 145. The apparatus of claim 145, wherein the mobile telephone signal is a CDMA signal. 149. The apparatus of claim 149, wherein the known component of the mobile telephone signal is an unmodulated PN sequence. 151. The apparatus of claim 150, wherein the broadcast TV signal is selected from the following signals. -ATSC digital TV signal, ETSI DVB-T signal, Japanese ISDB-T signal, and -Analog TV signal. 145. The method of claim 145, The receiver means receives a GPS signal from a GPS satellite at a user terminal, Wherein said processor means determines a third pseudo-range by a GPS satellite and a user terminal based on a GPS signal, and The processor means determines the position of the user terminal based on the first, second, third pseudo-ranges, the position of the TV signal transmitter, the position of the mobile telephone base station, and the position of the GPS satellites. Device for positioning a user terminal, characterized in that. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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