Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/0009—Transmission of position information to remote stations
  • G01S5/0018—Transmission from mobile station to base station
  • G01S5/0036—Transmission from mobile station to base station of measured values, i.e. measurement on mobile and position calculation on base station
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
  • G01S5/0205—Details
  • G01S5/0215—Interference
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
  • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
  • G01S19/03—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
  • G01S19/09—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing processing capability normally carried out by the receiver
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
  • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
  • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
  • G01S19/42—Determining position
  • G01S19/45—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement
  • G01S19/46—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement the supplementary measurement being of a radio-wave signal type
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
  • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
  • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
  • G01S19/42—Determining position
  • G01S19/48—Determining position by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/0009—Transmission of position information to remote stations
  • G01S5/0045—Transmission from base station to mobile station
  • G01S5/0054—Transmission from base station to mobile station of actual mobile position, i.e. position calculation on base station
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/0009—Transmission of position information to remote stations
  • G01S5/0081—Transmission between base stations
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
  • G01S5/0205—Details
  • G01S5/021—Calibration, monitoring or correction
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
  • G01S5/14—Determining absolute distances from a plurality of spaced points of known location
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
  • G01S5/14—Determining absolute distances from a plurality of spaced points of known location
  • G01S5/145—Using a supplementary range measurement, e.g. based on pseudo-range measurements
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
  • G01S5/0205—Details
  • G01S5/0226—Transmitters
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
  • G01S5/0205—Details
  • G01S5/0236—Assistance data, e.g. base station almanac

Definitions

• the present invention relates generally to position determination, and particularly to position determination using broadcast television signals and mobile telephone signals.
• GPS Global Positioning System
• GPS has revolutionized the technology of navigation and position location.
• GPS is less effective. Because the GPS signals are transmitted at relatively low power levels (less than 100 watts) and over great distances, the received signal strength is relatively weak (on the order of -160 dBw as received by an omni-directional antenna). Thus the signal is marginally useful or not useful at all in the presence of blockage or inside a building.
• NSC National Television System Committee
• the present analog TV signal contains horizontal and vertical synchronization pulses intended for relatively crude synchronization of the TV set sweep circuitry.
• FCC Federal Communication Commission
• the invention features a method, apparatus, and computer-readable media for determining the position of a user terminal. It comprises receiving at the user terminal a broadcast television signal from a television signal transmitter; determining a first pseudo-range between the user terminal and the television signal transmitter based on a known component of the broadcast television signal; receiving at the user terminal a mobile telephone signal from a mobile telephone base station; determining a second pseudo-range between the user terminal and the mobile telephone base station based on a known component of the mobile telephone signal; and determining a position of the user terminal based on the first and second pseudo-ranges, a location of the television signal transmitter, and a location of the mobile telephone base station.
• the mobile telephone signal is a Global System for Mobile Communications (GSM) signal.
• the known component of the mobile telephone signal is a training sequence.
• the broadcast television signal is selected from the group comprising an American Television Standards Committee (ATSC) digital television signal; a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting - Terrestrial (DVB-T) signal; a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB- T) signal; and an analog television signal.
• the mobile telephone signal is a Code-Division Multiple Access (CDMA) signal.
• CDMA Code-Division Multiple Access
• the known component of the mobile telephone signal is an unmodulated PN sequence.
• Implementations can comprise receiving at the user terminal a global positioning signal from a global positioning satellite; determining a third pseudo-range between the user terminal and the global positioning satellite based on the global positioning signal; and determining a position of the user terminal based on the first, second and third pseudo-ranges, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• the invention features a method, apparatus, and computer-readable media for determining the position of a user terminal.
• It comprises receiving at the user terminal a broadcast television signal from a television signal transmitter; determining a pseudo-range between the user terminal and the television signal transmitter based on a known component of the broadcast television signal; receiving at the user terminal a mobile telephone signal from a mobile telephone base station, the mobile telephone signal comprising a range signal; determining a range between the user terminal and the mobile telephone base station based on the range signal; and determining a position of the user terminal based on the pseudo-range, the range, a location of the television signal transmitter, and a location of the mobile telephone base station.
• the mobile telephone signal is a Global System for Mobile Communications (GSM) signal, and the range signal comprises a timing advance parameter.
• the broadcast television signal is selected from the group comprising an American Television Standards Committee (ATSC) digital television signal; a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting - Terrestrial (DVB-T) signal; a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) signal; and an analog television signal.
• ATSC American Television Standards Committee
• ETSI European Telecommunications Standards Institute
• DVD-T Digital Video Broadcasting - Terrestrial
• ISDB-T Japanese Integrated Services Digital Broadcasting-Terrestrial
• Implementations can comprise determining a second pseudo-range between the user terminal and the mobile telephone base station based on a known component of the mobile telephone signal; and determining a position of the user terminal based on the first and second pseudo-ranges, the range, a location of the television signal transmitter, and a location of the mobile telephone base station.
• the known component of the mobile telephone signal is a training sequence.
• Implementations can comprise receiving at the user terminal a global positioning signal from a global positioning satellite; determining a third pseudo-range between the user terminal and the global positioning satellite based on the global positioning signal; and determining a position of the user terminal based on the first, second and third pseudo-ranges, the range, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• Implementations can comprise receiving at the user terminal a global positioning signal from a global positioning satellite; determining a second pseudo-range between the user te ⁇ ninal and the global positioning satellite based on the global positioning signal; and determining a position of the user terminal based on the first and second pseudo-ranges, the range, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• the invention features a method, apparatus, and computer-readable media for determining the position of a user terminal. It comprises receiving at the user tenninal a broadcast television signal from a television signal transmitter; determining a first pseudo-range between the user terminal and the television signal transmitter based on a known component of the broadcast television signal; receiving at the user terminal a mobile telephone signal from a mobile telephone base station; determining a second pseudo-range between the user terminal and the mobile telephone base station based on a known component of the mobile telephone signal; and transmitting the first and second pseudoranges to a location server configured to determine a position of the user terminal based on the first and second pseudo-ranges, a location of the television signal transmitter, and a location of the mobile telephone base station.
• the mobile telephone signal is a Global System for Mobile Communications (GSM) signal.
• the known component of the mobile telephone signal is a training sequence.
• the broadcast television signal is selected from the group comprising an American Television Standards Committee (ATSC) digital television signal; a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting - Terrestrial (DVB-T) signal; a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB- T) signal; and an analog television signal.
• the mobile telephone signal is a Code-Division Multiple Access (CDMA) signal.
• CDMA Code-Division Multiple Access
• the known component of the mobile telephone signal is an unmodulated PN sequence.
• Implementations can comprise receiving at the user terminal a global positioning signal from a global positioning satellite; determining a third pseudo-range between the user terminal and the global positioning satellite based on the global positioning signal; and transmitting the first, second and third pseudoranges to a location server configured to determine a position of the user terminal based on the first, second and third pseudo-ranges, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• the invention features a method, apparatus, and computer-readable media for determining the position of a user terminal.
• It comprises receiving at the user terminal a broadcast television signal from a television signal transmitter; determining a pseudo-range between the user terminal and the television signal transmitter based on a known component of the broadcast television signal; receiving at the user terminal a mobile telephone signal from a mobile telephone base station, the mobile telephone signal comprising a range signal; determining a range between the user terminal and the mobile telephone base station based on the range signal; and ttansmitting the pseudorange and the range to a location server configured to determine a position of the user terminal based on the pseudorange, the range, a location of the television signal transmitter, and a location of the mobile telephone base station.
• Particular implementations can 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 comprises a timing advance parameter.
• the broadcast television signal is selected from the group comprising an American Television Standards Committee (ATSC) digital television signal; a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting - Terrestrial (DVB-T) signal; a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) signal; and an analog television signal.
• ATSC American Television Standards Committee
• ETSI European Telecommunications Standards Institute
• DVD-T Digital Video Broadcasting - Terrestrial
• ISDB-T Japanese Integrated Services Digital Broadcasting-Terrestrial
• Implementations can comprise determining a second pseudo-range between the user terminal and the mobile telephone base station based on a known component of the mobile telephone signal; and transmitting the first and second pseudo- ranges and the range to a location server configured to determine a position of the user terminal based on the first and second pseudo-ranges, the range, a location of the television signal transmitter, and a location of the mobile telephone base station.
• the known component of the mobile telephone signal is a training sequence.
• Implementations can comprise receiving at the user terminal a global positioning signal from a global positioning satellite; determining a third pseudo-range between the user terminal and the global positioning satellite based on the global positioning signal; and transmitting the first, second and third pseudo-ranges and the range to a location server configured to determine a position of the user terminal based on the first, second and third pseudo- ranges, the range, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• Implementations can comprise receiving at the user terminal a global positioning signal from a global positioning satellite; determining a second pseudo-range between the user terminal and the global positioning satellite based on the global positioning signal; and transmitting the first and second pseudo-ranges and the range to a location server configured to determine a position of the user terminal based on the first and second pseudo-ranges, the range, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• the invention features a method, apparatus, and computer-readable media for determining the position of a user terminal.
• the mobile telephone signal is a Global System for Mobile Communications (GSM) signal.
• GSM Global System for Mobile Communications
• the known component of the mobile telephone signal is a training sequence.
• the broadcast television signal is selected from the group comprising an American Television Standards Committee (ATSC) digital television signal; a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting - Terrestrial (DVB-T) signal; a Japanese Integrated Services Digital Broadcasting- Terrestrial (ISDB-T) signal; and an analog television signal.
• the mobile telephone signal is a Code-Division Multiple Access (CDMA) signal.
• CDMA Code-Division Multiple Access
• the known component of the mobile telephone signal is an unmodulated PN sequence.
• Implementations can comprise receiving a third pseudo-range between the user terminal and a global positioning satellite based on a global positioning signal transmitted by the global positioning satellite; and determining a position of the user terminal based on the first, second and third pseudo- ranges, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• the invention features a method, apparatus, and computer-readable media for determining the position of a user terminal.
• It comprises receiving a pseudo-range between the user terminal and a television signal transmitter, the pseudo-range determined based on a known component of a broadcast television signal transmitted by the television signal transmitter; receiving a range between the user terminal and a mobile telephone base station, the range determined based on a range signal transmitted by the mobile telephone base station; and determining a position of the user terminal based on the pseudorange, the range, a location of the television signal transmitter, and a location of the mobile telephone base station.
• the mobile telephone signal is a Global System for Mobile Communications (GSM) signal
• the range signal comprises a timing advance parameter.
• GSM Global System for Mobile Communications
• the broadcast television signal is selected from the group comprising an American Television Standards Committee (ATSC) digital television signal; a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting - Terrestrial (DVB-T) signal; a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) signal; and an analog television signal.
• Implementations can comprise receiving a second pseudo-range between the user terminal and the mobile telephone base station, the second pseudo-range determined based on a known component of the mobile telephone signal; and determining a position of the user terminal based on the first and second pseudo-ranges, the range, a location of the television signal transmitter, and a location of the mobile telephone base station.
• the known component of the mobile telephone signal is a training sequence.
• Implementations can comprise receiving a third pseudo-range between the user terminal and the global positioning satellite, the third pseudo-range determined based on a global positioning signal transmitted by the global positioning satellite; and determining a position of the user terminal based on the first, second and third pseudo-ranges, the range, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• Implementations can comprise receiving a second pseudo-range between the user terminal and a global positioning satellite, the second pseudo-range determined based on a global positioning signal transmitted by the global positioning satellite; and determining a position of the user terminal based on the first and second pseudo-ranges, the range, a location of the television signal transmitter, a location of the mobile telephone base station, and a location of the global positioning satellite.
• FIG. 1 depicts an implementation of the present invention including a user terminal that communicates over an air link with a base station.
• FIG. 2 illustrates an operation of an implementation of the invention.
• FIG. 3 depicts the geometry of a position determination using 3 DTV transmitters.
• FIG. 4 shows the format for the normal burst of the GSM signal.
• FIG. 5 shows the format of the SACCH channel.
• FIG. 6 shows a system configuration with only two DTV transmitters in view with good geometry, and with only one GSM base station in view, of a user terminal.
• FIG. 7 shows a position solution using the GSM timing advance without further modification, along with the measurements of two DTV signals.
• FIG. 8 shows a simplified configuration of a time-gated delay lock loop that is used to measure the pseudorange by comparing the measured synchronization time with the local reference clock in the user terminal in one embodiment.
• the leading digit(s) of each reference numeral used in this specification indicates the number of the drawing in which the reference numeral first appears.
• Broadcast television signals can be used to determine the position of a user terminal.
• Techniques for determining the position of a user terminal using the American Television Standards Committee (ATSC) digital television (DTV) signal are disclosed in commonly-owned copending U.S. Non-provisional Patent Application Serial No. 09/887,158, "Position Location using Broadcast Digital Television Signals," by James J. Spilker and Matthew Rabinowitz, filed June 21, 2001, the disclosure thereof inco ⁇ orated by reference herein in its entirety.
• Techniques for determining the position of a user terminal using the European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting-Terrestrial (DVB-T) signal are disclosed in commonly-owned copending U.S. Non-provisional Patent Application Serial No.
• Each of these television signals includes components that can be used to obtain a pseudo-range to the transmitter of the television signal. When multiple such pseudo-ranges are known, and the locations of the transmitters are known, the position of the user terminal can be determined with accuracy.
• Suitable components within the ATSC digital television signal include synchronization codes such as the Field Synchronization Segment within an ATSC data frame and the Synchronization Segment within a Data Segment within an ATSC data frame.
• Suitable components within the ETSI DVB-T and ISDB-T digital television signals include scattered pilot carriers.
• Suitable components within the NTSC analog television signal include the horizontal synchronization pulse, the horizontal blanking pulse, the horizontal blanking pulse and horizontal synchronization pulse taken together, the ghost canceling reference signal; and the vertical interval test signal.
• a user terminal using these techniques can determine its positipn using combinations of broadcast television signals and mobile telephone base station signals.
• the mobile telephone signals used include Global System for Mobile Communications (GSM) signals and Code-Division Multiple Access (CDMA) signals, as described in detail below.
• GSM Global System for Mobile Communications
• CDMA Code-Division Multiple Access
• Additional pseudoranges can be supplied using a standard global positioning system (GPS) receiver.
• GPS global positioning system
• an example implementation 100 includes a user terminal
• base station 104 is part of a mobile MAN (metropolitan area network) or WAN (wide area network).
• FIG. 1 is used to illustrate various aspects of the invention but the invention is not limited to this implementation.
• the phrase "user terminal” is meant to refer to any object capable of implementing the position location techniques described herein. Examples of user terminals include PDAs, mobile phones, cars and other vehicles, and any object which could include a chip or software implementing the position location techniques described herein. Further, the term “user terminal” is not intended to be limited to objects which are "terminals” or which are operated by "users.”
• FIG. 2 illustrates an operation of implementation 100.
• User terminal 102 receives broadcast signals from one or more TV transmitters 106A and 106B through 106N (step 202).
• TV transmitter 106 A is a ETSI transmitter
• TV transmitter 106B is a NTSC transmitter
• TV transmitter 106N is a ATSC transmitter, although other combinations are contemplated, including transmitters of the ISDB signal used in Japan.
• a location server 110 tells user terminal 102 of the best TV channels to monitor.
• user terminal 102 exchanges messages with location server 110 by way of base station 104.
• user terminal 102 selects TV channels to monitor based on the identity of base station 104 and a stored table correlating base stations and TV channels.
• user terminal 102 can accept a location input from the user that gives a general indication of the location of the user terminal, such as the name of the nearest city; and uses this information to select TV channels for processing.
• user terminal 102 scans available TV channels to assemble a fmge ⁇ rint of the location based on power levels of the available TV channels. User terminal 102 compares this finge ⁇ rint to a stored table that matches known finge ⁇ rints with known locations to select TV channels for processing.
• User terminal 102 determines a pseudo-range between the user terminal and each TV transmitter 106 (step 204).
• Each pseudo-range represents the time difference (or equivalent distance) between a time of transmission from a transmitter 108 of a component of the TV broadcast signal and a time of reception at the user terminal 102 of the component, as well as a clock offset at the user terminal.
• location server 110 is implemented as a general-p pose computer executing software designed to perform the operations described herein.
• location server is implemented as an ASIC (application-specific integrated circuit), or some other sort of device.
• location server 110 is implemented within or near base station 104.
• the TV signals are also received by a plurality of monitor units 108A through 108N.
• Each monitor unit 108 can be implemented as a small unit including a transceiver and processor, and can be mounted in a convenient location such as on a utility pole, TV transmitter 106, or base station 104. In some implementations, monitor units 108 are implemented on satellites.
• Each monitor unit 108 measures, for each of the TV transmitters 106 from which it receives TV signals, a time offset between the local clock of that TV transmitter and a reference clock. In some implementations the reference clock is derived from GPS signals.
• each time offset is modeled as a fixed offset.
• each time offset is modeled as a second order polynomial fit of the form
• Offset a + b(t -T)+c(t -Tf (1)
• each measured time offset is transmitted periodically to the location server using the Internet, a secured modem connection or the like.
• the location of each monitor unit 108 is determined using GPS receivers.
• Location server 110 receives information describing the phase center (i.e., the location) of each TV transmitter 106 from a database 112.
• the phase center of each TV transmitter 106 is measured by using monitor units 108 at different locations to measure the phase center directly.
• the phase center of each TV transmitter 106 is measured by surveying the antenna phase center.
• location server 110 receives weather information describing the air temperature, atmospheric pressure, and humidity in the vicinity of user terminal 102 from a weather server 114.
• the weather information is available from the Internet and other sources such as NOAA.
• Location server 110 determines tropospheric propagation velocity from the weather information using techniques such as those disclosed in B. Parkinson and J. Spilker, Jr. Global Positioning System-Theory and Applications, AIAA, Washington, DC, 1996, Vol. 1, Chapter 17 Tropospheric Effects on GPS by J. Spilker, Jr.
• Location server 110 can also receive from base station 104 information which identifies a general geographic location of user terminal 102.
• the information can identify a cell or cell sector within which a cellular telephone is located. This information is used for ambiguity resolution.
• User terminal 102 receives mobile telephone signals from one or more mobile telephone base stations 104 (step 206).
• the mobile telephone signals can include range signals such as the GSM timing advance parameter.
• User terminal 102 determines a range and/or pseudo-range between the user terminal and each mobile telephone base station 104 (step 208). The range can be obtained from the range signal, as described in detail below.
• Each pseudo-range represents the time difference (or equivalent distance) between a time of transmission from a mobile telephone base station 104 of a component of the mobile telephone signal and a time of reception at the user terminal 102 of the component, as well as a clock offset at the mobile telephone base station.
• User terminal 102 transmits the pseudo-ranges to location server 110.
• Location server 110 determines a position of the user terminal based on the pseudo-ranges, the ranges if used, a location of each of the TV transmitters 106, and a location of the mobile telephone base stations 104 (step 210).
• FIG. 3 depicts the geometry of a position determination using three transmitters 302.
• Transmitters 302 can include any combination of TV transmitters and mobile telephone base stations.
• Transmitter 302 A is located at position (xl, yl, zl). The range between user terminal 102 and transmitter 302A is rl.
• Transmitter 302B is located at position (x2, y2, z2). The range between user terminal 102 and transmitter 302B is r2.
• Transmitter 302N is located at position (x3, y3, z3). The range between user terminal 102 and transmitter 302N is r3.
• Location server 110 may adjust the value of each pseudo-range according to the tropospheric propagation velocity and the time offset for the corresponding transmitter 302.
• Location server 110 uses the phase center information from database 112 to determine the position of each transmitter 302.
• the locations of and clock offsets for GSM base stations can be obtained from the E-OTD assistance data broadcast message transmitted by the GSM base station.
• User terminal 102 makes three or more pseudo-range measurements to solve for three unknowns, namely the position (x, y) and clock offset TOf user terminal 102. It is assumed that the altitude of the user terminal is known to within the necessary degree of accuracy and only the latitude and longitude of the user terminal need to be precisely determined.
• XI represents the three-dimensional vector position (xl, yl, zl) of transmitter 302A
• X2 represents the three-dimensional vector position (x2, y2, z2) of transmitter 302B
• X3 represents the three-dimensional vector position (x3, y3, z3) of transmitter 302N.
• the initial estimate of z can be iteratively refined based on the computed values for x andy.
• location server 110 actively solves for z. Location server 110 solves these equations according to conventional well-known methods.
• the position of user terminal 102 is transmitted to E911 location server 116 for distribution to the proper authorities.
• the position is transmitted to user terminal 102.
• user terminal 102 does not compute pseudo- ranges, but rather takes measurements of the signals that are sufficient to compute pseudo-range, and transmits these measurements to location server 110.
• Location server 110 then computes the pseudo-ranges based on the measurements, and computes the position based on the pseudo-ranges, as described above.
• the position of user terminal 102 is computed by user terminal 102.
• all of the necessary information is transmitted to user terminal 102.
• This information can be transmitted to user terminal 102 by location server 110, base station 104, one or more TV transmitters 106, mobile telephone base stations 104, or any combination thereof.
• User terminal 102 measures the pseudo- ranges and solves the simultaneous equations as described above. This implementation is now described.
• User terminal 102 receives the time offset between the local clock of each
• User terminal 102 also receives information describing the phase center of each TV transmitter 106 from a database 112.
• User terminal 102 receives the tropospheric propagation velocity computed by location server 110.
• user terminal 102 receives weather information describing the air temperature, atmospheric pressure, and humidity in the vicinity of user terminal 102 from a weather server 114, and determines tropospheric propagation velocity from the weather information using conventional techniques.
• User terminal 102 can also receive from base station 104 information which identifies the rough location of user terminal 102. For example, the information can identify a cell or cell sector within which a cellular telephone is located. This information is used for ambiguity resolution.
• User terminal 102 receives TV signals from one or more TV transmitters 106 and determines a pseudo-range between the user tenninal 102 and each TV transmitter 106.
• User terminal 102 receives mobile telephone signals from one or more mobile telephone base stations 104, and determines pseudo-ranges and/or ranges between the user terminal 102 and the mobile telephone base stations 104.
• User terminal 102 determines its position based on the pseudo-ranges, the ranges if used, the locations of the TV transmitters 106, and the locations of the mobile telephone base stations 104.
• the position of user terminal 102 can be determined using a TV transmitter and the offset T computed during a previous position determination for that TV transmitter.
• the values of T can be stored or maintained according to conventional methods.
• base station 104 determines the clock offset of user terminal 102. In this implementation, only two transmitters are required for position determination. Base station 104 transmits the clock offset Tto location server 110, which then determines the position of user terminal 102 from the pseudo-range computed for each of the transmitters.
• the GSM signal has 124 each 200 kHz frequency channels plus a 200 kHz guard band for a total bandwidth of 25 MHz for transmit and 25 MHz for receive.
• Each frequency channel is then modulated by a 270.8333 kbps Gaussian minimal shift keyed signal with a TDMA frame subdivided into 8 time slots shared by 8 different active users.
• a pair of frequency channels with 45 MHz separation is allocated to a given duplex channel.
• the GSM signal has 5 different burst formats: normal burst, frequency correction burst, synchronization burst, dummy burst, and access burst.
• the synchronization burst is used for timing with a 64 bit training sequence in place of the normal 26 bit training sequence.
• the dummy burst has no data but is otherwise the same as the normal burst.
• the access burst has a much larger 68.25 guard space, a 41 bit training sequence, and only 36 data bits.
• the format for the normal burst is shown in FIG. 4.
• the format includes 3 tail bits 402, followed by 57 data bits 404, followed by a 26-bit synchronization training sequence 406, followed by 57 data bits 408, followed by 3 tail bits 410, followed by 8.25 guard bits 412.
• the training sequences in these various burst formats are known bit patterns which are used by embodiments of the present invention for timing synchronization. There are 8 different training sequences for the normal burst transmission which are designated by the base station color code. Training sequences are used both to adjust the adaptive equalizers and to correct for propagation delay.
• User terminals enter the system by making requests on one of the random access channels. However in order for the TDM A signals with 8 bursts per TDMA frame to operate properly, user terminals at different distances from the base station must transmit their TDMA bursts at different time offsets in order for their TDMA busts to be received at the base station with proper timing and no overlap between bursts. [0067] For this pu ⁇ ose the base station transmits a range signal comprising a timing advance parameter. Of course if other such other range signals are available, they can be used instead.
• the timing advance parameter has 64 steps corresponding to 1 data bit each, and corresponds to twice the one-way propagation time.
• each increment is 1.846 microseconds or 1846 ft of range for free-space propagation.
• the timing advance parameter by itself gives a range accuracy from the base station to the user terminal of approximately +/- 307.6 yards or 302.7 meters. Although this accuracy is not as good as might be desired, it is already available at the user terminal, and when combined with the high accuracy of the television signal measurements, produces an acceptable solution in outlying areas where only two TV signals are in view with good geometry.
• the timing advance parameter is transmitted as one of the signaling channels used in GSM.
• DCCH dedicated control channels
• One of these DCCH channels is a two-way (between the user terminal and the base station) slow associated control channel (SACCH) channel, which contains the 7-bit timing advance information.
• SACCH slow associated control channel
• FIG. 5 shows a system configuration with only two DTV transmitters 106 in view with good geometry, and with only one GSM base station 104 in view, of user terminal 102. Of course, if additional GSM base stations 104 are in view their signals can be used to improve the accuracy of the position location.
• GSM base station transceiver system BTS
• BSC base station controller
• the GSM system measurements can take one of several forms.
• One embodiment uses the normal GSM timing advance parameter, which is always provided. The accuracy is not as good as might be desired. However, it requires no addition to normal GSM operation except that the timing advance is also fed to location server 110 along with the other DTV signal measurements, for example using one or more GSM short message service (SMS) messages.
• SMS GSM short message service
• Another embodiment measures the pseudorange between user terminal 102 and base station 104, and uses this pseudorange along with the pseudoranges between user terminal 102 and DTV transmitters 106 to solve for the position of the user terminal with higher accuracy.
• This embodiment includes a pseudorange delay lock loop operating on the GSM training sequence.
• the training sequences in other types of GSM bursts can be used as well.
• FIG. 7 shows a position solution using the GSM timing advance without further modification, along with the measurements of two DTV signals.
• the GSM timing advance provides a locus of solutions which is simply an arc 702 of radius corresponding to the timing advance in nanoseconds times the speed of light in the atmosphere.
• the two DTV solution simply gives a hyperbola 704 corresponding to the delay difference.
• the position solution is then the intersection 706 of arc 702 and the appropriate hyperbola 704.
• Other approaches to solution can be found also.
• FIG. 8 shows a simplified configuration of a time-gated delay lock loop
• Time-gated DLL Time-gated DLLs are disclosed in detail in U.S. Non-provisional Patent Application Serial No. 10/054,262, "Time-Gated Delay Lock Loop Tracking Of Digital Television Signals," by James J. Spilker and Matthew Rabinowitz, filed January 22, 2002, the disclosure thereof inco ⁇ orated by reference herein in its entirety.
• FIG. 8 shows a noncoherent type delay lock loop, it should be understood that coherent forms of the time-gated delay lock loop can be used as well. Because the GSM receiver must operate coherently, there is sufficient signal level and clock recovery to operate the DLL in the coherent mode.
• Time-gate controller 802 generates a time-gate signal that turns the memoryless elements of receiver 800 on and off to conserve power, such that these elements are operational and producing signals only when those signals are needed.
• Time- gate controller 802 is controlled by timing signals generated by local clock 804 based on the timing of the training sequence. Elements in the front end of the receiver (not shown) can be time-gated as well. This saves substantial power, making implementations especially suit uable for portable devices having limited power resources.
• the received GSM signal is passed by a switch 806, also controlled by time- gate controller 802, to a pair of mixers 808 A and 808B, where it is mixed with I and Q samples of the training sequence, respectively, which are provided by training sequence generator 810.
• NCDs 814 are combined by a summer 816 and filtered by a DLL loop filter 818.
• the ou ⁇ ut of filter 818 drives a number-controlled oscillator (NCO) 820 that is clocked by local clock 804 and drives training sequence generator 810.
• NCO number-controlled oscillator
• TGDLL 800 can use not only the 26-bit training sequence in the GSM normal bursts, but also training sequences in the other GSM bursts and various control signals broadcast from GSM base station 104. These various approaches permit measurements with a greater accuracy than that obtained using the timing advance parameter alone. In some embodiments the timing advance parameter is used as an acquisition aid.
• Location processor 110 also accounts for the position of the base station antenna and the sector being used by the user terminal.
• the clock timing of the base station must be known. This is easily accomplished if the base station clock is locked to GPS or some other timing source, and the distance from the clock to the antenna is calculated or measured.
• CDMA Code Division Multiple Access
• each cell site PN sequence is offset by some multiple of 64 chips. There are 512 unique offsets. All base stations in an area use different offsets to minimize interference and aid user terminal acquisition of the strongest base station signal. This method of using offsets of the same sequences in transmit signals requires that all base stations maintain a stable time reference that allows for time synchronization of their transmitters. All CDMA cell sites obtain their time reference with GPS receivers.
• the IS-95 digital cellular system operates in the same band as the current analog cellular band (AMPS) in which full-duplex operation is achieved by using frequency division duplexing with 25 MHz in each direction, with an uplink (user terminal to base station) band of 869-894 MHz and a downlink (base station to user terminal) band of 824-849 MHz.
• the 25 MHz band for each direction is divided into 20 bands where each band of 1.25 MHz uses a single carrier with a PN sequence in the 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 a high power pilot channel, low power synchronization channel, and 62 paging and traffic channels.
• the pilot chaimel allows user terminals to acquire and track base station signals.
• a user terminal acquires the strongest of these unmodulated pilot channel signals from different base stations it finds by ranging over all the offset time shifts of the PN sequences.
• the synchronization channel allows user terminals to time-synchronize to the selected base station network.
• Each of these downlink channels use one of 64 orthogonal Walsh codewords which allow separation of the channels that are using the same 1.25 MHz band.
• a user terminal uses one of the 64 Walsh codeword to receive from one of these base station channels.
• the pilot channel is the highest power channel and uses the all zero Walsh codeword, which means that this signal is unmodulated PN sequence.
• This pilot channel is orthogonal to all the other channels when cross correlations are done over the time interval of the 64-bit Walsh codeword.
• TGDLL 800 of FIG. 8 can be implemented in user terminal 102, where training sequence generator generates the unmodulated PN sequence.
• the invention can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations thereof.
• Apparatus of the invention can be implemented in a computer program product tangibly embodied in a machine-readable storage device for execution by a programmable processor; and method steps of the invention can be performed by a programmable processor executing a program of instructions to perform functions of the invention by operating on input data and generating output.
• the invention can be implemented advantageously in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device.
• Each computer program can be implemented in a high-level procedural or object-oriented programming language, or in assembly or machine language if desired; and in any case, the language can be a compiled or inte ⁇ reted language.
• Suitable processors include, by way of example, both general and special pu ⁇ ose microprocessors.
• a processor will receive instructions and data from a readonly memory and/or a random access memory.
• a computer will include one or more mass storage devices for storing data files; such devices include magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and optical disks.
• Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM disks. Any of the foregoing can be supplemented by, or inco ⁇ orated in, ASICs (application-specific integrated circuits).
• semiconductor memory devices such as EPROM, EEPROM, and flash memory devices
• magnetic disks such as internal hard disks and removable disks
• magneto-optical disks magneto-optical disks
• CD-ROM disks CD-ROM disks
• Location server 110 employs redundant signals available at the system level, such as pseudo-ranges available from the TV transmitters, making additional checks to validate each TV channel and pseudo-range, and to identify TV channels that are erroneous.
• RAIM receiver autonomous integrity monitoring

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  • 2002-08-29 JP JP2003525316A patent/JP2005502054A/ja active Pending
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