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GB1605207A - Systems to assist in the location of remote radio transmitters - Google Patents

Systems to assist in the location of remote radio transmitters Download PDF

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Publication number
GB1605207A
GB1605207A GB2584675A GB2584675A GB1605207A GB 1605207 A GB1605207 A GB 1605207A GB 2584675 A GB2584675 A GB 2584675A GB 2584675 A GB2584675 A GB 2584675A GB 1605207 A GB1605207 A GB 1605207A
Authority
GB
United Kingdom
Prior art keywords
radio
transmitter
location
remote
radar
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
GB2584675A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems Electronics Ltd
Original Assignee
Marconi Co 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 Marconi Co Ltd filed Critical Marconi Co Ltd
Priority to GB2584675A priority Critical patent/GB1605207A/en
Publication of GB1605207A publication Critical patent/GB1605207A/en
Expired legal-status Critical Current

Links

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
    • G01S5/02—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
    • G01S5/12—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 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
    • 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
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • 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
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/003—Bistatic radar systems; Multistatic radar systems
    • 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
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radar Systems Or Details Thereof (AREA)

Description

(54) IMPROVEMENTS IN OR RELATING TO SYSTEMS TO ASSIST IN THE LOCATION OF REMOTE RADIO TRANSMITTERS (71) We, THE MARCONI COMPANY LIMITED, of Marconi House, New Street, Chelmsford, CMl 1PL, Essex, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to systems to assist in the location of remote radio transmitters. Such a system may determine the range, or some other location parameter, of a remote radio transmitter. This determined information may be used with other information, for example, the bearing of the remote transmitter, to enable the position of the transmitter to be located.
The invention is based on the realisation that if the aerial of a radio transmitter operating at a frequency in, say, the H.F., V.H.F., or U.H.F.
band lies in a relatively strong radiation field from a high power microwave transmitter, cross-modulation may occur with the result that the radio signal actually transmitted has superimposed on it any modulation of the microwave radiation. Such cross-modulation may occur if both the radio signal required to be transmitted and the microwave signal picked up by the aerial are applied to a nonlinear impedance, for example the output stage of the transmitter. Alternatively cross-modulation may be produced in the transmitter aerial structure or neighbouring metalwork due to nonQinearity of the electric and/or magnetic characteristics of the metal used. The level of such crosslnodulation is, of course, usually very low.
According to one aspect of the present invention, a system to assist in the location of a remote radio transmitter comprises a radio transmitting system which is adapted to transmit modulated radio signals, a radio receiving system that is arranged to receive radio signals transmitted by the remote transmitter, and means to determine a measure of the sum of the distances from the radio transmitting system to the remote transmitter and from the remote transmitter to the radio receiving system by time correlating the modulation trans mitted by the radio transmitting system with the same modulation superimposed on the radio signals received by said receiving system from the remote transmitter.
If the radio transmitting system and the radio receiving system are at the same location, the time correlation gives a measure of twice the range of the remote transmitter from that location.
According to another aspect of the present invention, a system to assist in the location of a remote radio transmitter comprises a first radio receiving system for receiving modulated radio signals transmitted by another remote radio transmitter, a second radio receiving system for receiving radio signals from the remote radio transmitter that is to be located, and means to determine a location parameter of the latter transmitter by tirne correlating the modulation received by the first radio receiving system with the same modulation superimposed on the radio signals received by the second radio receiving system.
Examples of systems in accordance with the present invention will now be described with reference to the two figures of the accompanying drawing which show two systems respectively.
Refering now to Figure 1 of the accompanying drawing, the first system to be described comprises a microwave radio transmitting system 1, for example having an operating frequency of l000MHz, which has a narrow beam steerable aerial 2. The transmitted carrier is amplitude (or otherwise) modulated by a pulse or other signal. During use the radiated beam is periodically scanned over the area in which lies a remote transmitter 3 that is to be located.
The system also includes a radio receiving system 4 which is located at a distance from the transmitting system 1 and which is tuned to the frequency of the transmitter 3. A correlator 5, which may conveniently be formed by a suitably programmed general purpose digital computer, is arranged to effect time correlation of the modulation transmitted by the system 1 and the cross-modulation superimposed on to the radio signals transmitted by the system 3.
When the correlator 5 establishes time corre lation, the information supplied thereby is a measure of the time taken for radio waves to travel from the transmitting system 1 to the ) remote transmitter 3 and from the transmitter 3 to the receiving system 4 i.e. the sum of the path lengths L1 and L2. It follows therefore that the remote transmitter 3 lies on an ellipse 6, its major axis passing through the locations of the systems 1 and 4. Furthermore, when correlation is established, the direction in which the aerial 2 is then pointing gives a bear ing of the remote transmitter 3.
The aerial 7 of the radio receiving system 4 may also be directional, but less so than the aerial 2 of the transmitting system 1 ,and may be operated so that, at any time, it is pointing in the same general direction as the aerial 2.
From the information obtained as aforesaid, the position of the transmitter 3 may readily be determined, for example by a computer.
It is, of course, desirable for the field strength of the radiation from the radio trans mitting system 1 to be as high as possible in the I region of the remote transmitter 3. To this end it is convenient for the radio transmitting sys tem 1 to be the transmitting end of a pulsed radar. Since however the operation of time cor relation takes a relatively long time to carry out, the rate of scan is preferably rather lower than that utilised in its alternative radar mode of operation. Furthermore the pulse recurrence frequency is preferably not greater than 7,500 per second so that measurements of the range of a remote transmitter can be made up to 20 kilometres without ambiguity.
Instead of utilising the modulation of a co operating radio transmitter system (from which the modulation signal is directly available) to cross-modulate the radiated signal of the re mote transmitter, some other radio transmit ting system to which there is no direct access may be used. Such an arrangement will now be described with reference to Figure 2 of the accompanying drawing (which utilises the same reference numbers as Figure 1 for correspond ing items.) Referring now to Figure 2, the system for locating the remote transmitter 3 again includes a radio transmitting system 1 which may, for example, be provided by a pulsed radar that is periodically scanning the area in which the transmitter 3 is located.In this case, in addition to the receiving system 4 that responds to the signal radiated by the transmitter 3 and carry ing the cross-modulation, a second radio receiv ing system 8 is provided at the same location to pick up directly the signal transmitted by the radar or other radio transmission system 1. The receiving system 8 thus derives a modulation signal in which the cross-modulation signal supplied by the receiving system 4 is time correlated by means of the correlator 5.
In the arrangement described in the last paragraph, the result of effecting the time correlation is to determine a measure of the distance from the radar 1, say, to the transmitter 3 plus the distance from that transmitter to the location of the two receiving systems 4 and 8 less the distance from the radar 1 to said location. This identifies a particular ellipse on which the transmitter 3 lies, this ellipse having a major axis passing through the location of the systems 4 and 8 and the location of the radar 1.
If now the two radio receiving systems are duplicated at another location, a second ellipse on which the transmitter 3 lies can be determined in similar manner and the intersection of the two ellipses gives the position of the transmitter 3. More generally, if the location of the radar 1 is not otherwise known, the information available by time correlating the crossmodulation received at each location with the corresponding modulation directly received from the radar 1, comparison of the time receipt of the radar transmission at the two locations and, possibly, the bearing of the radar l from one of the locations, the positions of both the radar 1 and the transmitter 3 may be determined. A digital computer is preferably utilised for carrying out the necessary calculations.
WHAT WE CLAIM IS: 1. A system to assist in the location of a remote radio transmitter comprising a radio transmitting system which is adapted to transmit modulated radio signals, a radio receiving system that is arranged to receive radio signals transmitted by the remote transmitter, and means to determine the measure of the sum of the distances from the radio transmitting system to the remote transmitter and from the remote transmitter to the radio receiving system by time correlating the modulation transmitted by the radio transmitting system with the same modulation superimposed on the radio signals received by said receiving system from the remote transmitter.
2. A location system according to Claim 1 wherein the radio transmitting system and the radio receiving system are at the same location.
3. A location system according to Claim 1 or Claim 2 wherein the radio transmission system has a narrow beam steerable aerial which is arranged periodically to scan the area in which the remote transmiiter lies.
4. A location system according to Claim 3 wherein a computer is arranged to determine the position of the remote transmitter utilising the time correlation information obtained as aforesaid and the bearing of the steerable aerial of the transmission system at the time of correlation.
5. A location system according to any preceeding claim wherein said radio transmitting
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    programmed general purpose digital computer, is arranged to effect time correlation of the modulation transmitted by the system 1 and the cross-modulation superimposed on to the radio signals transmitted by the system 3.
    When the correlator 5 establishes time corre lation, the information supplied thereby is a measure of the time taken for radio waves to travel from the transmitting system 1 to the ) remote transmitter 3 and from the transmitter
    3 to the receiving system 4 i.e. the sum of the path lengths L1 and L2. It follows therefore that the remote transmitter 3 lies on an ellipse 6, its major axis passing through the locations of the systems 1 and 4. Furthermore, when correlation is established, the direction in which the aerial 2 is then pointing gives a bear ing of the remote transmitter 3.
    The aerial 7 of the radio receiving system 4 may also be directional, but less so than the aerial 2 of the transmitting system 1 ,and may be operated so that, at any time, it is pointing in the same general direction as the aerial 2.
    From the information obtained as aforesaid, the position of the transmitter 3 may readily be determined, for example by a computer.
    It is, of course, desirable for the field strength of the radiation from the radio trans mitting system 1 to be as high as possible in the I region of the remote transmitter 3. To this end it is convenient for the radio transmitting sys tem 1 to be the transmitting end of a pulsed radar. Since however the operation of time cor relation takes a relatively long time to carry out, the rate of scan is preferably rather lower than that utilised in its alternative radar mode of operation. Furthermore the pulse recurrence frequency is preferably not greater than 7,500 per second so that measurements of the range of a remote transmitter can be made up to 20 kilometres without ambiguity.
    Instead of utilising the modulation of a co operating radio transmitter system (from which the modulation signal is directly available) to cross-modulate the radiated signal of the re mote transmitter, some other radio transmit ting system to which there is no direct access may be used. Such an arrangement will now be described with reference to Figure 2 of the accompanying drawing (which utilises the same reference numbers as Figure 1 for correspond ing items.) Referring now to Figure 2, the system for locating the remote transmitter 3 again includes a radio transmitting system 1 which may, for example, be provided by a pulsed radar that is periodically scanning the area in which the transmitter 3 is located.In this case, in addition to the receiving system 4 that responds to the signal radiated by the transmitter 3 and carry ing the cross-modulation, a second radio receiv ing system 8 is provided at the same location to pick up directly the signal transmitted by the radar or other radio transmission system 1. The receiving system 8 thus derives a modulation signal in which the cross-modulation signal supplied by the receiving system 4 is time correlated by means of the correlator 5.
    In the arrangement described in the last paragraph, the result of effecting the time correlation is to determine a measure of the distance from the radar 1, say, to the transmitter 3 plus the distance from that transmitter to the location of the two receiving systems 4 and 8 less the distance from the radar 1 to said location. This identifies a particular ellipse on which the transmitter 3 lies, this ellipse having a major axis passing through the location of the systems 4 and 8 and the location of the radar 1.
    If now the two radio receiving systems are duplicated at another location, a second ellipse on which the transmitter 3 lies can be determined in similar manner and the intersection of the two ellipses gives the position of the transmitter 3. More generally, if the location of the radar 1 is not otherwise known, the information available by time correlating the crossmodulation received at each location with the corresponding modulation directly received from the radar 1, comparison of the time receipt of the radar transmission at the two locations and, possibly, the bearing of the radar l from one of the locations, the positions of both the radar 1 and the transmitter 3 may be determined. A digital computer is preferably utilised for carrying out the necessary calculations.
    WHAT WE CLAIM IS: 1. A system to assist in the location of a remote radio transmitter comprising a radio transmitting system which is adapted to transmit modulated radio signals, a radio receiving system that is arranged to receive radio signals transmitted by the remote transmitter, and means to determine the measure of the sum of the distances from the radio transmitting system to the remote transmitter and from the remote transmitter to the radio receiving system by time correlating the modulation transmitted by the radio transmitting system with the same modulation superimposed on the radio signals received by said receiving system from the remote transmitter.
  2. 2. A location system according to Claim 1 wherein the radio transmitting system and the radio receiving system are at the same location.
  3. 3. A location system according to Claim 1 or Claim 2 wherein the radio transmission system has a narrow beam steerable aerial which is arranged periodically to scan the area in which the remote transmiiter lies.
  4. 4. A location system according to Claim 3 wherein a computer is arranged to determine the position of the remote transmitter utilising the time correlation information obtained as aforesaid and the bearing of the steerable aerial of the transmission system at the time of correlation.
  5. 5. A location system according to any preceeding claim wherein said radio transmitting
    system is a pulsed radar transmitter.
  6. 6. A system to assist in the location of a remote radio transmitter comprising a first radio receiving system for receiving modulated radio signals transmitted by another remote radio transmitter, a second radio receiving system for receiving radio signals from the remote radio transmitter that is to be located, and means to determine a location parameter of the latter transmitter by time correlating the modulation received by the first radio receiving system with the same modulation superimposed on the radio signals received by the second radio receiving system.
  7. 7. A location system according to Claim 6 wherein the first and second radio receiving systems are duplicated at another location and a computer is arranged to determine the position of the remote transmitter utilising information obtained by time correlating the modulator received by the first radio receiving system at each location with the same modulation superimposed on the radio signals received by the second radio receiving system at that location.
  8. 8. A system to assist in the location of a remote radio transmitter substantially as hereinbefore described with reference to Figure 1 of the accompanying drawing.
  9. 9. A system to assist in the location of a remote radio transmitter substantially as hereinbefore described with reference to Figure 2 of the accompanying drawing.
GB2584675A 1975-06-17 1975-06-17 Systems to assist in the location of remote radio transmitters Expired GB1605207A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2584675A GB1605207A (en) 1975-06-17 1975-06-17 Systems to assist in the location of remote radio transmitters

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2584675A GB1605207A (en) 1975-06-17 1975-06-17 Systems to assist in the location of remote radio transmitters

Publications (1)

Publication Number Publication Date
GB1605207A true GB1605207A (en) 1983-10-05

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GB2584675A Expired GB1605207A (en) 1975-06-17 1975-06-17 Systems to assist in the location of remote radio transmitters

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6236365B1 (en) 1996-09-09 2001-05-22 Tracbeam, Llc Location of a mobile station using a plurality of commercial wireless infrastructures
US6249252B1 (en) 1996-09-09 2001-06-19 Tracbeam Llc Wireless location using multiple location estimators
US7274332B1 (en) 1996-09-09 2007-09-25 Tracbeam Llc Multiple evaluators for evaluation of a purality of conditions
US7298327B2 (en) 1996-09-09 2007-11-20 Tracbeam Llc Geographic location using multiple location estimators
US7714778B2 (en) 1997-08-20 2010-05-11 Tracbeam Llc Wireless location gateway and applications therefor
US7903029B2 (en) 1996-09-09 2011-03-08 Tracbeam Llc Wireless location routing applications and architecture therefor
US8082096B2 (en) 2001-05-22 2011-12-20 Tracbeam Llc Wireless location routing applications and architecture therefor
US8135413B2 (en) 1998-11-24 2012-03-13 Tracbeam Llc Platform and applications for wireless location and other complex services
US8694025B2 (en) 1999-09-24 2014-04-08 Dennis Dupray Geographically constrained network services
US9134398B2 (en) 1996-09-09 2015-09-15 Tracbeam Llc Wireless location using network centric location estimators
US9538493B2 (en) 2010-08-23 2017-01-03 Finetrak, Llc Locating a mobile station and applications therefor
US9875492B2 (en) 2001-05-22 2018-01-23 Dennis J. Dupray Real estate transaction system
US10641861B2 (en) 2000-06-02 2020-05-05 Dennis J. Dupray Services and applications for a communications network
US10684350B2 (en) 2000-06-02 2020-06-16 Tracbeam Llc Services and applications for a communications network

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8994591B2 (en) 1996-09-09 2015-03-31 Tracbeam Llc Locating a mobile station and applications therefor
US7903029B2 (en) 1996-09-09 2011-03-08 Tracbeam Llc Wireless location routing applications and architecture therefor
US6952181B2 (en) 1996-09-09 2005-10-04 Tracbeam, Llc Locating a mobile station using a plurality of wireless networks and applications therefor
US7274332B1 (en) 1996-09-09 2007-09-25 Tracbeam Llc Multiple evaluators for evaluation of a purality of conditions
US7298327B2 (en) 1996-09-09 2007-11-20 Tracbeam Llc Geographic location using multiple location estimators
US7525484B2 (en) 1996-09-09 2009-04-28 Tracbeam Llc Gateway and hybrid solutions for wireless location
US9237543B2 (en) 1996-09-09 2016-01-12 Tracbeam, Llc Wireless location using signal fingerprinting and other location estimators
US7764231B1 (en) 1996-09-09 2010-07-27 Tracbeam Llc Wireless location using multiple mobile station location techniques
US7812766B2 (en) 1996-09-09 2010-10-12 Tracbeam Llc Locating a mobile station and applications therefor
US9134398B2 (en) 1996-09-09 2015-09-15 Tracbeam Llc Wireless location using network centric location estimators
US8032153B2 (en) 1996-09-09 2011-10-04 Tracbeam Llc Multiple location estimators for wireless location
US9277525B2 (en) 1996-09-09 2016-03-01 Tracbeam, Llc Wireless location using location estimators
US6236365B1 (en) 1996-09-09 2001-05-22 Tracbeam, Llc Location of a mobile station using a plurality of commercial wireless infrastructures
US9060341B2 (en) 1996-09-09 2015-06-16 Tracbeam, Llc System and method for hybriding wireless location techniques
US6249252B1 (en) 1996-09-09 2001-06-19 Tracbeam Llc Wireless location using multiple location estimators
US7714778B2 (en) 1997-08-20 2010-05-11 Tracbeam Llc Wireless location gateway and applications therefor
US8135413B2 (en) 1998-11-24 2012-03-13 Tracbeam Llc Platform and applications for wireless location and other complex services
US9078101B2 (en) 1999-09-24 2015-07-07 Dennis Dupray Geographically constrained network services
US10455356B2 (en) 1999-09-24 2019-10-22 Dennis J. Dupray Network services dependent upon geographical constraints
US11765545B2 (en) 1999-09-24 2023-09-19 Dennis Dupray Network services dependent on geographical constraints
US8694025B2 (en) 1999-09-24 2014-04-08 Dennis Dupray Geographically constrained network services
US9699609B2 (en) 1999-09-24 2017-07-04 Dennis J. Dupray Network services dependent upon geographical constraints
US10641861B2 (en) 2000-06-02 2020-05-05 Dennis J. Dupray Services and applications for a communications network
US10684350B2 (en) 2000-06-02 2020-06-16 Tracbeam Llc Services and applications for a communications network
US11971491B2 (en) 2000-06-02 2024-04-30 Mobile Maven Llc Services and applications for a communications network
US9875492B2 (en) 2001-05-22 2018-01-23 Dennis J. Dupray Real estate transaction system
US11610241B2 (en) 2001-05-22 2023-03-21 Mobile Maven Llc Real estate transaction system
US8082096B2 (en) 2001-05-22 2011-12-20 Tracbeam Llc Wireless location routing applications and architecture therefor
US9538493B2 (en) 2010-08-23 2017-01-03 Finetrak, Llc Locating a mobile station and applications therefor
US10849089B2 (en) 2010-08-23 2020-11-24 Finetrak, Llc Resource allocation according to geolocation of mobile communication units
US12156165B2 (en) 2010-08-23 2024-11-26 Finetrak, Llc Resource allocation according to geolocation of mobile communication units related applications

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