WO1999011086A1 - Systeme de localisation en telephonie mobile numerique - Google Patents

Systeme de localisation en telephonie mobile numerique Download PDF

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Publication number
WO1999011086A1
WO1999011086A1 PCT/GB1998/002538 GB9802538W WO9911086A1 WO 1999011086 A1 WO1999011086 A1 WO 1999011086A1 GB 9802538 W GB9802538 W GB 9802538W WO 9911086 A1 WO9911086 A1 WO 9911086A1
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WO
WIPO (PCT)
Prior art keywords
mobile station
network
base stations
signal
location
Prior art date
Application number
PCT/GB1998/002538
Other languages
English (en)
Inventor
Peter Duffett-Smith
William Basil Harrold
Andrew Fogg
Original Assignee
Cambridge Positioning Systems Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cambridge Positioning Systems Ltd. filed Critical Cambridge Positioning Systems Ltd.
Priority to AU88707/98A priority Critical patent/AU8870798A/en
Priority to EP98940367A priority patent/EP1005773A1/fr
Priority to JP2000508213A priority patent/JP2001514476A/ja
Publication of WO1999011086A1 publication Critical patent/WO1999011086A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
    • 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
    • G01S5/0218—Multipath in signal reception
    • 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
    • G01S5/0205—Details
    • G01S5/0221—Receivers
    • 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
    • G01S5/10—Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements, e.g. omega or decca systems

Definitions

  • the invention relates to a digital cellular radio communication network, such as a GSM (Global System for Mobile Communication), or CDMA (Code Division Multiple
  • the invention also relates to a location system, including a digital cellular radio communication network, for use in tracking a fleet of vehicles, each one of which includes a mobile station, and/or in a vehicle navigation system.
  • the principle of determining the position of a mobile radio-receiving apparatus by measuring time-of-flight differences between radio signals from several transmitters is well known, and a number of systems have been proposed and implemented. Most of the known systems rely on precise time synchronisation of the transmitters so that time-of-flight differences can be directly calculated. Knowing the geographical locations of the transmitters, particular values of these time differences identify a hyperbolic surface, in the space between each pair of transmitters being monitored, on which the radio-receiving apparatus must lie. Given three such hyperbolic surfaces, i.e. derived from three transmitters taken in pairs, the mobile radio-receiving apparatus must lie at the Intersection of the surfaces.
  • the target mobile station, 5, is adapted to monitor the same broadcast signals as the reference mobile station, 1. At some point in time, the target mobile station, 5, makes a short recording of each of the signals broadcast by the three transmitters, 2 to 4. The three recordings made by the target mobile station, 5, must be precisely spaced in time The reference mobile station, 1 , makes a similar set of recordings, almost simultaneously with the recordings made by the target mobile station, 5 It is important that the three recordings are made at precisely the same interval in the reference mobile station, 1, and the target mobile station, 5.
  • Close synchronisation of the start time for the recordings reduces the amount of: computation needed to determine the geographic location of the target mobile station 5; and - storage needed in the reference mobile station, 1 , and the target mobile station 5 by reducing the lengths of the recordings that must be made at the reference mobile station, 1 , but does not affect the accuracy of the determined geographic location and so is not critical
  • a representation of the three recordings is communicated from the target mobile station, 5, to the reference mobile station, 1 , where correlation techniques are used to determine the time offsets between the signals as received at the target mobile station, 5, and as received at the reference mobile station, 1.
  • the recordings are long enough to ensure that the worst-case time offsets between reference and target recordings will still result in substantial overlap of the recordings. Since the geographic locations of the three transmitters, 2 to 4, and of the reference mobile station, 1, are known, the observed time of flight differences can be used to determine the location of the target mobile station 5 and the synchronisation offset between the reference mobile station 1 and the target mobile station 5, by solving the equations given in EP-B-0 303 371.
  • the transmitters, 2 to 4 may, for example, be base stations (BSs) in a digital cellular radio communications network, such as a GSM, or CDMA, network. It should be noted that differences in the exact time when the recordings start can be eliminated in the subsequent position calculation.
  • BSs base stations
  • CDMA digital cellular radio communications network
  • the system of Figure 1 of the accompanying drawings has several disadvantages, namely a reference mobile station is needed in order to capture a reference copy of the broadcast signals at a known location; substantial computing power is needed to perform the necessary correlations to determine the time offset between the signals, as seen at the reference mobile station, and the signals, as seen at the target mobile station, assuming that position determination is required with only a short time delay, a near-real-time communications link is needed to transfer the recordings made at the target mobile station to the reference mobile station for correlation each time it is required to determine the geographic location of a target mobile station; the bandwidth required for said communication link may be considerable, increasing the cost of said communication, - the reference mobile station, in the system of Figure 1 , has to perform recordings and correlations for all target mobile stations wishing to determine their geographic locations, at any point in time, thereby further increasing the computation capacity needed in the reference mobile station; and - if the need for position information is, in fact, at the target mobile station, rather than some central location, a further real-time communications link is needed to transmit
  • a digital cellular radio communication network such as a GSM, or CDMA
  • This is effected by providing a system wherein signal structures are used which are designed to have good auto-correlation properties in TDMA broadcast channels, or CDMA pilots, conveying system information from each base station (BS) of the network, and wherein such signals are repeated at predictable/predetermined intervals in time that are identifiable from other information in the broadcast signal, for example, by frame numbering.
  • a digital cellular radio communication network including a plurality of subscriber mobile stations; a number of base stations, each one of which is adapted to communicate with a number of mobile stations and has a known fixed geographic location in the network; and location means for determining the geographic location of a mobile station in the network, said location means including at least one reference mobile station having a known geographic location in the network and being adapted to receive signals broadcast by said base stations, said received signals being used to determine the geographic location of a subscriber mobile station in the network, characterised in that a mobile station includes means for identifying and measuring the time of arrival of a signal broadcast by a base station, each broadcast signal received by said mobile station being a composite signal consisting of one or more copies of a signal transmitted by a respective base station, said copies being displaced in time relative to each other according to the relative lengths of the paths traversed by each copy between the respective base station and the mobile station, and said time of arrival being measured as the time of arrival of the earliest arriving
  • Identifying, and measuring the time of arrival of, the earliest-arriving copy of said composite signal may be done as described later.
  • the signals transmitted in digital cellulartelephone networks include parts which are transmitted at known intervals and which are readily identifiable and known in advance.
  • the time of arrival of a signal received from a base station, relative to said internal time base is identified and measured, in time or equivalent transformed space, by auto-correlating a measured part of said signal; constructing a template comprising a portion of the auto-correlation of an expected part of said signal and a portion of the auto-correlation of a part of the measured part of said signal; cross-correlating the expected part of said received signal with the measured part of said received signal; and measuring the offset at which the template best fits the cross-correlation as the time of arrival of the signal broadcast by a base station relative to said internal time base.
  • the invention also includes a mobile station comprising means for carrying out the above method.
  • the signal parts which are readily identifiable and known in advance, in the case of a GSM system may be, for example, the extended training sequence.
  • the parts of the signal may be pilot spreading codes.
  • the signals may be broadcast on a Broadcast Control Channel (BCCH) of each of said base stations, a BCCH signal transmitted by a base station conveying to the mobile stations, with which said base station is adapted to communicate, information concerning said base station and the digital cellular radio communication network, and the handset may be adapted to determine the relative timings of the signals broadcast by a number of base stations using, for example, frame numbering and other identifying features of said BCCH signals.
  • BCCH Broadcast Control Channel
  • the network may be either a GSM, or a CDMA, network, and the the relative timings of the signals broadcast by a number of base stations may be determined using, in the case of GSM, a training sequence in the TDMA frames, and, in the case of CDMA, pilot spreading codes.
  • the network may include evaluation means for evaluating said relative timings of said signals to determine the geographic location of said mobile station in the network, and transmission means for transmitting said relative timings from said mobile station to said evaluation means.
  • the mobile station may include means adapted to receive, from said evaluation means, data concerning its geographic location in the network, and to store said data.
  • a mobile station may include means adapted to receive, from at least one external source, information on said relative timings and geographical locations of said base stations, and to store said information.
  • a mobile station may include location means adapted to determining the mobile station's geographic location in said network using said relative timings, in combination with base station timing and geographic location information.
  • the mobile station used to determine said relative timings may be a reference mobile station, and the reference mobile station may include calculation means adapted to calculate differences in bit and frame timing between transmissions from different base stations, in combination with information concerning said reference mobile station's geographic location and said base stations' geographic locations, said calculated data being used to determine the RTDs (Real Time Differences) of the base stations and thereby the geographic location of a subscriber mobile station.
  • RTDs Real Time Differences
  • the reference mobile station may include means adapted to determine, and predict, a rate of change of said timing differences between base stations.
  • the reference mobile station may include transmission means for transmitting said calculated relative timings and rates of change to an external system for use in geographic position determination.
  • the transmission means may be adapted to transmit base station position information to said external system.
  • the reference mobile station may have a known fixed geographic location in the network.
  • the geographic location of said reference mobile station in the network may be variable but determinable at any instant in time, for example, by using the signals of the Global Positioning System, GPS.
  • At least some of said base stations may each have a reference mobile station integral therewith.
  • the invention also includes a location system including a digital cellular radio communication network as outlined above.
  • the location system may include a control centre for controlling operation of the system.
  • the location system may be adapted to determine the geographic location of any one of said mobile stations (MSs) in said network, in which said relative timings of base stations (BSs) used to determine said geographic locations are subject to variations at a rate approaching that of a signalling frame rate of signals transmitted by said base stations, in which said system includes a reference mobile station for each set of base stations used to determine said geographic locations, in which a mobile station, whose location is to be determined (herein referred to as a 'target mobile station'), is assigned a set of base stations by said control centre, said target mobile station being adapted to measure relative timings of signals transmitted by said assigned set of base stations, at times given in terms of the frame number at an agreed base station, in which at least one reference mobile station, associated with said assigned set of base stations, is adapted to measure relative timings of said signals transmitted by said assigned set of base stations, in which said target mobile station and said reference mobile station are adapted to transmit said measured timings to said control centre, in which said control centre is adapted to compare said time information from said target
  • the control centre may be adapted to change the set of base stations, assigned to a mobile station, as said mobile station travels within the coverage area of the digital cellular radio communication network.
  • the control centre may be adapted to co-ordinate information concerning timing measurements from at least some of said reference mobile stations.
  • the location system may be adapted to track a fleet of vehicles, each one of which includes a mobile station (MS).
  • the invention also includes a vehicle navigation system adapted to enable vehicles to determine their geographic locations, in which said navigation system includes a location system as outlined above, and in which each of said vehicles includes a mobile station (target mobile station).
  • the system may include a reference mobile station for each set of base stations used to determine said geographic locations, in which rates of change of relative timings between base stations are sufficiently stable to enable said relative timings to be accurately predicted, for relatively long periods of time, according to a model shared between said reference and target mobile stations, in which said control centre is adapted to collect relative timing information and rate of change information measured by each of said reference mobile stations for respective sets of base stations, in which said control centre is adapted to distribute measurement information collected from said reference mobile stations to target mobile stations, travelling within the coverage area of said digital cellular radio communication network, said information distribution being such that each of said target mobile stations has sufficiently accurate information concerning relative timings of base stations with which it can communicate in any given geographic location of said network, in which a target mobile station is adapted to measure relative timings of signals transmitted by a set of base
  • Figure 1 diagrammatically illustrates, in the form of a block diagram, a known system for determining the geographic location of a mobile receiving apparatus
  • Figure 2 diagrammatically illustrates, in the form of a block diagram, a digital cellular radio communication network of the present invention
  • Figures 3A-D illustrate estimated and measured auto- and cross-correlation functions of signals in the system as will be described below;
  • Figure 4 is a diagrammatic illustration of a mobile handset for a digital cellular radio network embodying the invention.
  • each base station (BS) of the network broadcasts signals on a Broadcast Control Channel (BCCH), to those of the network's mobile stations (MSs) within its coverage area, which convey information concerning the digital cellular system and the broadcasting base station.
  • BCCH Broadcast Control Channel
  • the BCCH radiated by a base station also includes signals to assist the mobile stations (MSs), within its coverage range, in acquiring synchronisation to the radiating base station, when a mobile station is first turned on, or when the mobile station re-enters the coverage area of the radiating base station, after a temporary loss of signal.
  • the BCCH signals include features designed to enable a mobile station to acquire and maintain bit synchronisation with the base station concerned; these features are transmitted at precise and regular intervals in the TDMA structure of the GSM network and are readily identifiable
  • the BCCH signals can be used to establish, with high accuracy, the bit and frame timing of any particular base station, as received at a mobile station.
  • the accuracy of the bit and frame timing information, established from the BCCH signals is typically a small fraction of a bit period.
  • the received signal is very likely to be a composite signal consisting of one, or more, copies of the signal transmitted by the base station, the copies being displaced in time, relative to each other, according to the relative lengths of the paths taken by each copy of the signal between the receiving mobile station and the transmitting base station.
  • the eariiest- arriving copy of the signal will be that copy which has taken the shortest path between the base station and mobile station, the shortest path need not necessarily be a direct path between the base station and mobile station.
  • the path error in the shortest received path will be the greatest single error source in most of the position measurements effected using the digital cellular radio communication network of the present invention.
  • This example of the present invention makes use of readily identifiable signal structures designed to have good auto-correlation properties, e.g. the extended training sequences in a GSM digital cellular network, and is illustrated in Figures 3A to 3D.
  • the auto-correlation function of the extended training sequence in a GSM signal (illustrated in Figure 3A) is well known.
  • the left hand side of this (corresponding to the negative time axis) is used as the left hand side of an estimated cross-correlation function (illustrated in Figure 3C) of the received signals and the expected extended training sequence.
  • the right hand side of the autocorrelation function of the measured extended training sequence (illustrated in Figure 3B and corresponding to the positive time axis) is used as the right hand side of the estimated cross-correlation function
  • the received signals are cross-correlated with the expected extended training sequence and the resulting measured cross-correlation function (illustrated in Figure 3D) compared with the estimated cross-correlation function (Figure 3C) to find the timing offset.
  • FIG 4 is a simplified diagram of a mobile station comprising a conventional digital cellular radio handset adapted to operate in accordance with the invention.
  • the handset 5 includes an antenna 51 which provides a signal to a receiver 52, from which the received signal is passed to a digital signal processor (DSP) 53.
  • the digital signal processor 53 has an associated RAM 54 and a ROM 55 or similar for containing software used by the DSP 53.
  • a conventional microprocessor 56 receives signals processed by the DSP and also has associated RAM 57 and ROM or similar 58 for containing operating software.
  • the other normal components of a cellular telephone handset, eg battery, keypad, LCD screen etc. are not shown as they are not germane to the present invention.
  • the DSP 53 and associated RAM 54 operating under the control of a modified program stored in ROM 55 operate to carry out the required signal measurements and the microprocessor 56 and associated RAM 57 operate to measure the timing offsets under the control of a modified program stored in the ROM 58.
  • a GSM mobile station includes a mechanism, e.g. an equaliser with a channel sounder, for determining which copy of a composite signal, resulting from a signal transmitted by a base station, the mobile station should select and use in order to achieve the lowest bit error rate in the demodulated signal.
  • a modified GSM mobile station may be used which includes equalising means (including a channel sounder) adapted to identify, and measure the time of arrival of, a signal transmitted by a base station.
  • equalising means including a channel sounder
  • the signal which is identified and measured by the equalising mechanism will be the earliest-arriving copy of the composite signal transmitted by a base station.
  • An equaliser operating in this mode, does not need to demodulate the signal but merely needs to establish its timing, and may, therefore, be able to operate at lower received signal levels than would normally be required by an equaliserto effect reliable demodulation of the signal.
  • Such a mobile station may be a reference mobile station (MS) and/or a target mobile station (MS), i.e. a mobile station whose geographic location in the coverage area of the network is to be determined.
  • MS reference mobile station
  • MS target mobile station
  • the identification of the times of arrival of the signals could be performed by an equalising means, in the form of the CDMA searcher element in the mobile station.
  • the reference mobile station, 1 , and the target mobile station, 5, of the GSM network are each adapted to communicate with the network's base stations (BSs), 2 to 4, and that the reference mobile station, 1 , and target mobile station, 5, are adapted to communicate with each other, probably by the GSM network.
  • the reference mobile station, 1 , and target mobile station, 5, each include means, e.g. an equaliser mechanism, as outlined in a preceding paragraph.
  • the reference mobile station, 1 has a known geographic location in the coverage area of the network.
  • the reference mobile station, 1, would normally have a known fixed geographic location in the network, but may have a geographic location which is variable but determinable at any instant in time, for example, by GPS.
  • at least some of the network's base stations may each have a reference mobile station integral therewith, i.e. formed as an integral part of a base station and thereby eliminating the need for a separate unit.
  • the reference mobile station, 1 receives signal transmissions from the three base stations (BSs), 2 to 4, and is adapted to calculated RTDs (Real Time Differences) between the base station signal transmissions using, for example, information concerning: the known geographic locations of the base station, 2 to 4, in the network; the known geographic location of the reference mobile station 1 , in the network; and measured time difference between the times of arrival of the signal transmissions at the reference mobile station 1.
  • RTDs Real Time Differences
  • the reference mobile station, 1 may, in accordance with the present invention, also be adapted to determine the rate of change of the RTDs.
  • the target mobile station, 5, receives the same set of signal transmissions as the reference mobile station, 1 , from the base stations, 2 to 4, and is adapted to determine OTDs (Observed Time Differences) between the set of signal transmissions.
  • OTDs Observed Time Differences
  • the OTDs and RTDs are then used, in combination with the information concerning geographic locations of the base stations (BSs), 2 to 4, to determine the geographic location of the target mobile station, 5, in the network using conventional hyperbolic geometry calculations.
  • the RTDs together with rate of change information, if available, are transmitted to the target mobile station, 5, by the reference mobile station, 1 , or the OTDs are transmitted by the target mobile station, 5, to the reference mobile station, 1 , after which the two sets of time differences are combined with knowledge of the geographic locations of the base stations (BSs), 2 to 4, to calculate the position of the target mobile using the conventional hyperbolic equations
  • the RTDs either alone, or in combination with the rate of change information, are transmitted to the target mobile station, 5, for use, in combination with the OTDs and the information concerning the geographic locations of the three base stations, 2 to 4, to determine the geographic location of the target mobile station, 1.
  • the OTDs are transmitted to the target mobile station, 1 , for use in combination with the RTDs either alone, or in combination with the rate of change information, and the information concerning the geographic locations of the three base stations, 2 to 4, to determine the geographic location of the target mobile station, 1
  • the present invention determines the RTDs between base station transmissions so that the standard DECCA- style, or LORAN-style, hyperbolic calculation can be used.
  • a reference mobile station at a precisely-known geographical location, to determine the relative bit and frame timings of a set of base stations. If these relative timings do not change, the reference mobile need not be permanently present, i.e. the relative timings can be determined once and for all in an initial survey However, if these relative timings do change for any reason (the usual case), the reference mobile station will need to be present to monitor the relative timings and update the information on such timings at a suitable rate This rate will depend, among other things, on the frequency of network reconfigurations and the relative frequency stability of the base stations.
  • the frequency with which updates need to be transmitted can be reduced by monitoring the rate of change of the relative timings and transmitting this information, along with the timings, at a specified start time.
  • the reference mobile station, 1, of a digital cellular radio communication network of the present invention may be adapted to initially establish relative time differences for the three base stations, 2 to 4, and to thereafter update the relative timing information at predetermined intervals of time, or when a change in the time difference information is detected, whichever is the earlier.
  • the reference mobile station, 1 includes monitoring means adapted to monitor a rate of change of the relative timings and to transmit, at regular intervals of time, information on the rate of change of the relative timings, together with the relative timings information.
  • the equaliser used by a mobile station may be provided with an alternative operating mode in which it identifies the earliest-arriving copy of the composite signal transmitted by a base station and measures the time of arrival of that copy relative to a suitable internal time base
  • an equaliser operating in this mode, does not need to demodulate the signal but merely needs to establish its timing, and may, therefore, be able to operate at lower received signal levels than would normally be required by an equaliser to effect reliable demodulation of the signal.
  • the mobile station of the present invention has the ability, using the alternative equaliser mode, to determine the relative timing of the signals from several base station BCCHs to a suitable/reasonable accuracy, taking account of frame numbering and other identifying features of the signal, particularly including (in the case of GSM), the training sequences in the TDMA frames.
  • the mobile may be provided with transmission means to transmit these relative timings to some other point whether remote, or local, for evaluation It will be directly evident to a person skilled in art that a target mobile station of a digital cellular radio communication network of the present invention, i.e.
  • ⁇ may include: means for receiving a computed position result from an external source; and means for receiving information on relative timing and geographical locations of base stations from an external source, or sources, whether remote, or local; either one, or both, of which may typically be provided as part of the normal communications functions of the mobile station.
  • a target mobile station may also include means for using base station timing and position information, together with locally measured relative timings, to compute its own position.
  • a reference mobile station of a digital cellular radio communication network of the present invention may include: means for using the relative timings measured between transmissions from different base stations, together with knowledge of the geographical locations of the base stations and knowledge of its own geographical location, to calculate the actual differences in bit and frame timing between transmissions from different base stations, as if observed at the actual base stations by precisely synchronised observers; means for determining and predicting the rate of change of the timing differences between base stations; means for transmitting the calculated relative timings and rates of change to external systems whether remote, or local, for use in determining the geographic location of a target mobile station; and means for transmitting base station position information to external systems for use in position determination.
  • a basic application of the digital cellular radio communication network of the present invention is in a location system adapted to determine the geographic locations of any one of a number of mobile stations in the network.
  • the location system of the present invention may, however, be used in a number of applications, for example, to track/monitor a fleet of vehicles, each one of which includes a mobile station (a target mobile station).
  • the location system may form part of a vehicle navigation system, in which a vehicle, having a mobile station (target mobile station) located therein, wishes to determine its own location whilst travelling within the coverage area of the digital cellular radio communication system.
  • a location system for tracking/monitoring a fleet of vehicles may be a relatively low cost application of the present invention in which a central site, or control centre, wishes to know the locations of any one of a number of vehicles, for example, a fleet of taxis, as they travel within the coverage area of the digital cellular radio communication network.
  • the relative timings of the base stations (BSs), used to determine the geographic locations of the vehicles are subject to variations at a rate approaching that of a signalling frame rate of the signals transmitted by the base stations. This implies that it will be necessary to provide a reference mobile station for each set of base stations used to determine the geographic locations.
  • a vehicle whose geographic location is to be determined, is assigned a set of base stations (BSs), for example, by the control centre, and the vehicle's mobile station is adapted, in a manner as previously outlined, to measure the relative timings of the assigned set of base stations, at times given in terms of the frame number at an agreed base station, either periodically, or on demand.
  • BSs base stations
  • a reference mobile station, associated with the assigned set of base stations is adapted, in a manner as previously outlined, to measure the related timings of the signals transmitted by the same set of base stations as the target mobile station (vehicle).
  • the measured timing information is transmitted by the reference mobile station and the target mobile station to the control centre.
  • the control centre is adapted to compare the timing information from the target mobile station with the timing information from the reference mobile station, i.e. timing information from the same set of base stations in the same frame numbers, as received by the reference mobile station, to determine a time difference.
  • the control centre calculates the geographic location of the vehicle (target mobile station) using the time difference information, and information, known to the control centre, concerning the geographic locations of the assigned set of base stations and the reference mobile station. The calculation is made using conventional hyperbolic geometry calculations.
  • the reference mobile stations are co-ordinated by a control centre, it may only be necessary for the signals broadcast by at least two base stations to be measured by a reference mobile station in order to fix the geographic location of a target mobile station.
  • the set of base stations assigned to a vehicle will be a subset of those base stations the transmitted signals of which the vehicle's mobile station can measure.
  • the control centre is adapted to change the set of base stations, assigned to a vehicle (target mobile station), as the vehicle travels within the coverage area of the digital cellular radio communication network.
  • a set of base stations to be used to fix the position of a vehicle would typically be updated from the control centre, as the vehicle travels around.
  • the set of base stations, the signal transmissions of which any given reference mobile station can measure will not, in general, be a superset of those base stations the signal transmissions of which a specific target mobile (vehicle) can measure. There is, therefore, a need for the control centre to be able to co-ordinate measurements from some, or all, of the reference mobile stations.
  • a vehicle navigation system in which each vehicle includes a mobile station
  • target mobile station to enable it to determine its geographic locations
  • BSs base stations
  • the rates of change of relative timings between base stations (BSs) are sufficiently stable to enable the relative timings to be accurately predicted, for relatively long periods of time, according to a model shared between a reference mobile station and a target mobile station, i.e. located in the vehicle wishing to determine its geographical location.
  • control centre is adapted to: - collect relative timing information and rate of change information measured by each of said reference mobile stations for respective sets of base stations; and distribute measurement information collected from the reference mobile stations to target mobile stations, travelling within the coverage area of the digital cellular radio communication network.
  • the distributed information is such that each of the target mobile stations (vehicles) has sufficiently accurate information concerning relative timings of base stations (BSs) with which it can communicate in any given geographic location of said network.
  • BSs base stations
  • the vehicle's target mobile station measures the relative timings of the signals transmitted by a set of base stations (BSs) in its current location (not typically congruent with the set of base stations it may use for communication), and determines its geographic location using the relative timing measurements, together with the rate of change information distributed by the control centre and information concerning the geographic locations of the set of base stations (BSs).
  • BSs base stations
  • the control centre of the vehicle navigation system may be adapted to provide, to the target mobile station, information concerning geographic locations of said set of base stations (BSs), or the target mobile station may include a database in which the information concerning the geographic locations of the set of base stations (BSs) may be stored.
  • BSs base stations
  • the location system has the following characteristics and/or advantages over known systems for determining the geographic location of mobile apparatus: a reference mobile station is needed to capture a reference copy of the signals broadcast by a set of base stations at known locations; however, this can be very similar to the target mobile station - usually needs to update the timing information only infrequently, and so is low cost; correlations between two live signal recordings, as proposed in our earlier system, are no longer needed to determine the time-of-flight differences, hence reducing the required computing capacity of the system; the amount of data required to be transferred between the reference and target mobile stations is relatively small and, in some modes of operation of the present invention, the transfer from the reference mobile station to the target mobile station is infrequent, thereby reducing the cost of operation of the location system of the present invention; the reference mobile stations have to perform a set of timing and rate of change measurements that is common to all target mobile stations, further reducing the computation capacity needed in the reference mobile station; and if

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

L'invention concerne un réseau de radiocommunication numérique cellulaire, par exemple du type GSM ou à accès multiple par code de répartition (AMRC), lequel comprend : une pluralité de stations mobiles, un certain nombre de stations de base (BS) conçues pour communiquer avec un certain nombre de stations mobiles et implantées chacune en un point géographique fixe connu sur le réseau, et un système de localisation pour déterminer l'emplacement géographique d'une station mobile sur le réseau. Ledit système comprend au moins une station mobile de référence à emplacement géographique connu sur le réseau et conçue pour recevoir les signaux émanant des stations de base. Les signaux ainsi reçus permettent de déterminer l'emplacement géographique d'une station mobile d'abonné sur le réseau. Chaque station mobile est conçue (a) pour déterminer et évaluer le temps d'arrivée de la copie d'un signal émis par une station de base, dont l'arrivée a été la plus précoce et qui a été reçue sous forme de composite de plusieurs copies, ledit temps d'arrivée étant mesuré par rapport à une base de temps interne de la station mobile considérée, et (b) pour déterminer les valeurs de cadencement relatives des signaux émis par un certain nombre de stations de base. Lesdites valeurs permettent de déterminer l'emplacement géographique de la station mobile dans le réseau. Il est possible de transmettre les signaux sur un canal balisé (BCCH) de chacune des stations de base, moyennant quoi un signal BCCH achemine vers une station mobile l'information concernant la station de base émettrice et le réseau de radiocommunication numérique cellulaire.
PCT/GB1998/002538 1997-08-23 1998-08-24 Systeme de localisation en telephonie mobile numerique WO1999011086A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU88707/98A AU8870798A (en) 1997-08-23 1998-08-24 Location system for digital mobile telephony
EP98940367A EP1005773A1 (fr) 1997-08-23 1998-08-24 Systeme de localisation en telephonie mobile numerique
JP2000508213A JP2001514476A (ja) 1997-08-23 1998-08-24 デジタル移動電話用位置確認システム

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9717844.6 1997-08-23
GBGB9717844.6A GB9717844D0 (en) 1997-08-23 1997-08-23 Improvements in,or relating to,digital cellular radio communication networks

Publications (1)

Publication Number Publication Date
WO1999011086A1 true WO1999011086A1 (fr) 1999-03-04

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Application Number Title Priority Date Filing Date
PCT/GB1998/002538 WO1999011086A1 (fr) 1997-08-23 1998-08-24 Systeme de localisation en telephonie mobile numerique

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EP (1) EP1005773A1 (fr)
JP (1) JP2001514476A (fr)
AU (1) AU8870798A (fr)
GB (1) GB9717844D0 (fr)
WO (1) WO1999011086A1 (fr)

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GB2359699A (en) * 2000-02-23 2001-08-29 Motorola Inc locating a mobile station in a cellular telephone network
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EP1245963A2 (fr) * 2001-03-27 2002-10-02 Pioneer Corporation Procédé et dispositif de localisation d'une station mobile
EP1278074A1 (fr) * 2001-07-17 2003-01-22 Cambridge Positioning Systems Limited Système de positionement par radio
EP1301054A1 (fr) * 2001-10-04 2003-04-09 Cambridge Positioning Systems Limited Concernant la coordination d'une référence de temps dans un terminal cellulaire ou une station de base
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WO2003052451A3 (fr) * 2001-12-14 2003-11-27 Qualcomm Inc Systeme de determination d'un systeme utilisant un systeme de communications cellulaires
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EP1235077A3 (fr) * 2001-02-27 2005-06-29 Pioneer Corporation Dispositif, procédé et système de localisation
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WO2001054422A3 (fr) * 2000-01-20 2002-01-17 Ericsson Telefon Ab L M Systeme et procede permettant d'obtenir la position d'une station mobile dans un systeme cellulaire amrc
WO2001054422A2 (fr) * 2000-01-20 2001-07-26 Telefonaktiebolaget Lm Ericsson (Publ) Systeme et procede permettant d'obtenir la position d'une station mobile dans un systeme cellulaire amrc
US7183942B2 (en) 2000-01-26 2007-02-27 Origin Technologies Limited Speed trap detection and warning system
GB2359699A (en) * 2000-02-23 2001-08-29 Motorola Inc locating a mobile station in a cellular telephone network
US7228228B2 (en) 2000-11-15 2007-06-05 Sagentia Limited Tag tracking
US7024331B2 (en) 2000-11-15 2006-04-04 Scientific Generics Limited Tag tracking
WO2002047419A1 (fr) * 2000-12-06 2002-06-13 University Of Surrey Positionnement de station mobile pour reseau ad-hoc integre
US7231216B2 (en) 2000-12-06 2007-06-12 University Of Surrey Mobile positioning using intergrated ad-hoc network
US7043257B2 (en) 2001-02-27 2006-05-09 Pioneer Corporation Positioning apparatus, positioning method, and positioning system
EP1235077A3 (fr) * 2001-02-27 2005-06-29 Pioneer Corporation Dispositif, procédé et système de localisation
EP1245963A2 (fr) * 2001-03-27 2002-10-02 Pioneer Corporation Procédé et dispositif de localisation d'une station mobile
EP1245963A3 (fr) * 2001-03-27 2006-02-22 Pioneer Corporation Procédé et dispositif de localisation d'une station mobile
KR100923601B1 (ko) * 2001-07-17 2009-10-23 캠브리지 포지셔닝 시스템스 리미티드 개선된 무선 위치확인 시스템
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EP2309287A3 (fr) * 2001-07-17 2012-01-25 Cambridge Positioning Systems Limited Améliorations apportées aux systèmes de positionnement radio
WO2003008990A3 (fr) * 2001-07-17 2003-09-25 Cambridge Positioning Sys Ltd Ameliorations apportees aux systemes de positionnement radio
CN100401091C (zh) * 2001-07-17 2008-07-09 剑桥定位系统有限公司 无线电定位系统的改进
EP1278074A1 (fr) * 2001-07-17 2003-01-22 Cambridge Positioning Systems Limited Système de positionement par radio
EP1301054A1 (fr) * 2001-10-04 2003-04-09 Cambridge Positioning Systems Limited Concernant la coordination d'une référence de temps dans un terminal cellulaire ou une station de base
WO2003030578A1 (fr) * 2001-10-04 2003-04-10 Cambridge Positioning Systems Limited Coordination du temps de reference dans un terminal cellulaire ou une station de base
US7295535B2 (en) 2001-11-13 2007-11-13 Nokia Corporation Method for signal acquisition in a wireless terminal and wireless terminal
CN100446435C (zh) * 2001-11-13 2008-12-24 诺基亚有限公司 无线终端中的信号捕获方法和无线终端
GB2382270B (en) * 2001-11-16 2006-06-14 Nec Technologies Improved location systems in cellular communications networks
GB2382270A (en) * 2001-11-16 2003-05-21 Nec Technologies Location system in cellular communication networks
CN100409028C (zh) * 2001-12-14 2008-08-06 高通股份有限公司 使用蜂窝通信系统的位置确定系统
US7877100B2 (en) 2001-12-14 2011-01-25 Qualcomm Incorporated Position determination system that uses A cellular communication system
WO2003052451A3 (fr) * 2001-12-14 2003-11-27 Qualcomm Inc Systeme de determination d'un systeme utilisant un systeme de communications cellulaires
US7508883B2 (en) 2002-06-17 2009-03-24 Cambridge Positioning Systems Limited Radio positioning systems
US8280412B2 (en) * 2002-07-31 2012-10-02 Interdigital Technology Corporation Method for enhanced mobile assisted positioning
US8174366B2 (en) 2003-03-03 2012-05-08 Veroscan, Inc. Interrogator and interrogation system employing the same
US8552869B2 (en) 2003-03-03 2013-10-08 Veroscan, Inc. Interrogator and interrogation system employing the same
US7760097B2 (en) 2003-03-03 2010-07-20 Veroscan, Inc. Interrogator and interrogation system employing the same
US7764178B2 (en) 2003-03-03 2010-07-27 Veroscan, Inc. Interrogator and interrogation system employing the same
US7671744B2 (en) 2003-03-03 2010-03-02 Veroscan, Inc. Interrogator and interrogation system employing the same
US7893840B2 (en) 2003-03-03 2011-02-22 Veroscan, Inc. Interrogator and interrogation system employing the same
US8063760B2 (en) 2003-03-03 2011-11-22 Veroscan, Inc. Interrogator and interrogation system employing the same
US8542717B2 (en) 2003-03-03 2013-09-24 Veroscan, Inc. Interrogator and interrogation system employing the same
WO2005013633A1 (fr) * 2003-08-04 2005-02-10 Locata Corporation Systeme et procede d'attenuation des artefacts de correlation croisee amcr et amelioration des rapports signal sur bruit dans les reseaux de localisation amrt
AU2004301677B2 (en) * 2003-08-04 2008-10-02 Locata Corporation Pty Ltd A system and method for the mitigation of CDMA cross-correlation artifacts and the improvement of signal-to-noise ratios in TDMA location networks
US10628645B2 (en) 2004-03-03 2020-04-21 Medical Ip Holdings, Lp Interrogator and interrogation system employing the same
US8948279B2 (en) 2004-03-03 2015-02-03 Veroscan, Inc. Interrogator and interrogation system employing the same
US11205058B2 (en) 2004-03-03 2021-12-21 Lone Star Scm Systems, Lp Interrogator and interrogation system employing the same
US9135669B2 (en) 2005-09-29 2015-09-15 Lone Star Ip Holdings, Lp Interrogation system employing prior knowledge about an object to discern an identity thereof
US8737990B2 (en) 2006-08-02 2014-05-27 Nagravision S.A. Method of local conditional access for mobile equipment
WO2008045622A1 (fr) * 2006-08-11 2008-04-17 Veroscan, Inc. Interrogateur et système d'interrogation utilisant cet interrogateur
US7755491B2 (en) 2007-08-13 2010-07-13 Veroscan, Inc. Interrogator and interrogation system employing the same
US9035774B2 (en) 2011-04-11 2015-05-19 Lone Star Ip Holdings, Lp Interrogator and system employing the same
US10324177B2 (en) 2011-04-11 2019-06-18 Lone Star Ip Holdings, Lp Interrogator and system employing the same
US10670707B2 (en) 2011-04-11 2020-06-02 Lone Star Ip Holdings, Lp Interrogator and system employing the same
US9470787B2 (en) 2011-04-11 2016-10-18 Lone Star Ip Holdings, Lp Interrogator and system employing the same

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GB9717844D0 (en) 1997-10-29
AU8870798A (en) 1999-03-16
EP1005773A1 (fr) 2000-06-07

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