WO2010051859A1 - Amélioration passive de signal radar - Google Patents

Amélioration passive de signal radar Download PDF

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Publication number
WO2010051859A1
WO2010051859A1 PCT/EP2008/065217 EP2008065217W WO2010051859A1 WO 2010051859 A1 WO2010051859 A1 WO 2010051859A1 EP 2008065217 W EP2008065217 W EP 2008065217W WO 2010051859 A1 WO2010051859 A1 WO 2010051859A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
bit stream
digital
transmitter
error correction
Prior art date
Application number
PCT/EP2008/065217
Other languages
English (en)
Inventor
Björn FRANZON
Lars Kanderhag
Original Assignee
Telefonaktiebolaget L M Ericsson (Publ)
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 Telefonaktiebolaget L M Ericsson (Publ) filed Critical Telefonaktiebolaget L M Ericsson (Publ)
Priority to PCT/EP2008/065217 priority Critical patent/WO2010051859A1/fr
Publication of WO2010051859A1 publication Critical patent/WO2010051859A1/fr

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
    • 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
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/285—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
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating

Definitions

  • This invention is related to radar passive systems More particularly, the invention relates to clutter and noise suppression in such systems
  • Conventional radar systems comprise a collocated transmitter and receiver, which usu- ally share a common antenna to transmit and receive A pulsed signal is transmitted and the time taken for the pulse to travel to the object and back allows the range of the object to be determined
  • a passive radar system there is no dedicated transmitter Instead, the receiver uses third-party transmitters in the environment, and measures the time difference of arrival between the signal arriving directly from the transmitter and the signal arriving via reflection from the object This allows the bi-static range of the object to be determined In addition to bi-static range, a passive radar will typically also measure the bi-static Doppler shift of the echo and also its direction of arrival These measurements allow the location, heading and speed of the object to be calculated In some cases, multiple transmitters and/or receivers can be employed to make several independent measurements of b ⁇ - static range, Doppler and bearing and hence significantly improve the final track accuracy
  • a passive transmitter 1 1 such as public domain WCDMA (wideband code division multiplex access), GSM (Global System for Mobile communications), DVB-T (Terrestrial digital video broadcasting), or analogue RF (Radio Frequency) signals that may be received by external users 17 may be used by the passive radar system as an unintended additional use
  • a target 14 is illuminated by signals from transmitter 11
  • a first antenna 16 of the passive radar system is adapted for receiving reflected signals C from the target 14
  • a second reference antenna of the passive radar system is adapted to receive signals A transmitted from the third party transmitter
  • Other objects 13 will also be illuminated and contribute with reflected signals B
  • all signals A, B and C may of course be received by both the first and second, reference antenna
  • a passive radar typically employs the following processing steps, which are identified in the schematic diagram of fig 2 - Reception of the direct signal from the transm ⁇ tter(s) and from the surveillance region on dedicated low-noise, linear, digital receivers (not shown)
  • US2002/0198650 shows a passive coherent location surveillance system comprising various signal processing steps Woodward, P M (1953) "Probability and information theory, with application to radar” England London ISBN 0-89006-103-3
  • the is object is solved by a Processing unit for a radar system adapted to detect targets by means of signal reflections caused by a transmitter , the transmitter being adapted for transmitting radio frequency signals which contain an underlying digital bit stream signal which may be processed according to a radio protocol error correction mechanism util- ized by external receivers
  • the radar system comprises at least one antenna a target signal path - at least conveying signal contributions as reflected from a potential target - and a reference signal path - at least conveying signal contributions from the transmitter - wherein both respective signal paths comprise analogue to digital converters providing respectively a reference signal and a target signal
  • the reference signal path moreover comprises a replication stage comprising a digital to bit stream converter, an error correction stage and a bit stream to digital converter
  • the error correction stage incorporates a radio protocol error correction mechanism corresponding to the error mechanism used by the external re-titivers, the bit stream to digital converter providing an improved estimate of the digital data steam underlying the radio frequency signal transmitted from the transmitter
  • a radar system comprising the processing stage comprising a cross correlation stage, wherein the improved es- timate of the bit stream of the reference path and the bit stream of the target path are fed to the cross correlation stage
  • a radar system adapted to detect targets by means of signal reflections caused by a an external transmitter, the external transmitter being adapted for transmitting radio frequency sig- nals which contain a an underlying digital bit stream signal which may be processed according to a radio protocol error correction mechanism utilized by external receivers, the radar system comprising at least one antenna, the method comprising the steps of
  • the error correction incorporates a radio protocol error correction mechanism corresponding to the error mechanism used by the external receivers, providing an improved estimate of the digital data steam underlying the radio frequency signal transmitted from the transmitter
  • Fig 1 shows basic elements of a known passive radar system
  • fig 2 shows circuit elements of a known passive radar system
  • fig 3 shows circuit elements of an embodiment of a passive radar according to the invention.
  • fig 4 shows a flow diagram relating to the embodiment shown in fig 3
  • the processing unit 1 may for instance be employed in a radar system as shown in fig 2, whereby elements signals provided by the fig 3 circuit according to the invention are provided to the CFAR detection circuit 22 shown in fig 2 Hence, the fig 3 elements and elements 22, 23 24, 25 and 26 constitute an embodiment of a passive radar system according to the invention
  • a reference antenna 15' and a target antenna 15 is provided
  • the reference antenna may preferably be formed as a directional antenna which is directed towards a passive transmitter 1 1
  • the target antenna 15' may also have directional properties and be adapted to be directed towards a target 14
  • the signal path of the reference antenna 15 shall be referred to as the reference path 3 while the signal path relating to the target antenna shall be denoted as target signal path 3'
  • target signal path 3' It should be noted that instead of two receiving antennas 15, 15', a single antenna could be used, although probably with inferior results
  • the reference signal path 3 and target signal path 3' share the same elements band pass filter 19, 19' and analogue to digital converters 195, 195' Band pass filters 19, 19' delimit the incoming signals from noise stemming from other RF sources in the environment than the reference transmitter in question
  • Analogue to digital converters 195, 195' transform the signals into the digital domain sig- nals S1 and SV, respectively
  • a replication stage 200 is provided
  • the digital signal S1 output from the analogue to digital converter 195 of the reference signal path is transformed into a bit stream S2 by digital to bit stream converter 197 which substantially cor- responds to a data bit stream that is basis for the radio frequency signal transmitted from the third party transmitter 11
  • This bit stream 2 may for instance correspond to a binary bit stream It is understood though, due to signal degradation and multipath fading, that the bit stream S2 is not identical to the bit stream transmitted from the transmitter 11
  • a digital error correction algorithm c(m) is performed in error correction stage 199 on the bit stream S2 in the reference signal path 3 whereby, the received signal S1 is "repaired" and an improved estimate S3 of the originally transmitted bit stream is established
  • the error correction mechanism c(m) performed in stage 199 should be chosen to correspond to the radio protocol error correction mechanism as used by the transmitter / receiver of the third party system
  • the third party transmitter 1 1 is a DVB-T system
  • a corresponding error correction stage as used in consumer DVB-T receivers according to such a system is incorporated in the error correction stage 199 of the passive radar system according to the invention
  • a corresponding error correction method is chosen in accordance with error correction mechanism data stored in database 198
  • Other error correction mechanisms corresponding to those used by other types of transmitters, e g GSM or VVCDMA transmitters are suitably also stored in data base 199
  • the external transmitter 11 could be constituted by not a third party but a system inherent component, e g a dedicated transmitter
  • the improved estimated bit stream S3 is converted back into a digital format S1__C which corresponds to the digital bit format SV provided by A/D converter 195' in target signal path 3'
  • the improved reference signal S1_C and the target signal S1 ' are fed to cross correlation stage 21 of the passive radar system according to the invention
  • a Processing unit 1 for a radar system 1 adapted to de- tect targets 14 by means of signal reflections caused by a transmitter 11 , the transmitter 11 being adapted for transmitting radio frequency signals A which contain an underlying digital bit stream signal S1 which may be processed according to a radio protocol error correction mechanism c(m) utilized by external receivers 17
  • the radar system 11 comprises at least one antenna 15, 16, a target signal path 3' - at least conveying signal contributions as reflected from a potential target 14 - and a reference signal path 3 - at least conveying signal contributions from the transmitter 11 - wherein both respective signal paths comprise analogue to digital converters 195, 195' providing respectively a reference signal S1 and a target signal SV
  • the reference signal path 3 moreover comprises a replication stage 200 comprising a digital to bit stream converter 197, an error correction stage 199 and a bit stream to digital converter 201
  • the error correction stage incorporates a radio protocol error correction mechanism c(m) corresponding to the error mechanism used by the external receivers, the bit stream to digital converter 201 providing an improved estimate S1__C of the digital data steam S1 underlying the radio frequency signal transmitted from the transmitter 1 1
  • a radar system comprising the processing stage 1 comprising a cross correlation stage 21 , wherein the improved estimate S1__C of the bit stream of the reference path 3 and the bit stream SV of the target path 3' are fed to the cross correlation stage 21
  • the information stored in the transmitted signal is reproduced into a copy that is as close the original signal sent by the transmitter as practical possible
  • the invention is particular effective when huge amount of digital information is transferred
  • Such signals can be used with advantage by the passive radar system according to the invention because such signals have a high bandwidth which gives good resolution at long distances and which results in easier detection of targets
  • targets are shown with more effect and with a higher precision, which again means that signals are less prone to get confused with noise
  • the result of utilizing the invention can be likened with having a cable with direct connection to the transmitter It is noted that the transmitter could even be satellite borne A plot of auto correlation of the reference signal would decrease faster by increasing distance, which probably would reduce the amplitude of the distance side lobes The only reflections in distance would be created by the signal itself
  • a radar system 1 adapted to detect targets 14 by means of signal reflections caused by a an external transmitter 11 , the external transmitter 11 being adapted for transmitting radio frequency signals A which contain a an underlying digital bit stream signal which may be processed according to a radio protocol error correction mechanism utilized by external receivers 17, the radar system 11 comprising at least one antenna 15, 16, the method comprising the steps of

Abstract

L'invention concerne un système radar (1) capable de détecter des cibles (14) par la réflexion du signal produite par un émetteur (11), ce dernier étant capable d'émettre des signaux de fréquence radio (A) qui contiennent un signal de flux binaire numérique sous-jacent (S1) qui peut être traité par un mécanisme de correction d'erreur du protocole radio (c(m)) utilisé par des récepteurs externes (17). Une phase de réplication (200) comprend un convertisseur numérique-flux binaire (197), une phase de correction d'erreur (199) et un convertisseur flux binaire-numérique (201), la phase de correction d'erreur comprenant un mécanisme de correction d'erreur de protocole radio (c(m)) correspondant au mécanisme d'erreur utilisé par les récepteurs externes, le convertisseur numérique-flux binaire (201) procurant une estimation améliorée (S1_C) du flux de données numériques (S1) sous-jacent du signal de fréquence émis par l'émetteur (11).
PCT/EP2008/065217 2008-11-10 2008-11-10 Amélioration passive de signal radar WO2010051859A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2008/065217 WO2010051859A1 (fr) 2008-11-10 2008-11-10 Amélioration passive de signal radar

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2008/065217 WO2010051859A1 (fr) 2008-11-10 2008-11-10 Amélioration passive de signal radar

Publications (1)

Publication Number Publication Date
WO2010051859A1 true WO2010051859A1 (fr) 2010-05-14

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102087354A (zh) * 2010-12-15 2011-06-08 哈尔滨工程大学 无源雷达分组ls-clean微弱目标检测方法
CN104237859A (zh) * 2014-08-27 2014-12-24 武汉大学 利用gpu实现外辐射源雷达多通道时域杂波抑制的方法
CN104267375A (zh) * 2014-10-08 2015-01-07 武汉大学 一种外辐射源雷达网误差自配准方法
WO2015063488A1 (fr) * 2013-10-30 2015-05-07 Ucl Business Plc Appareil et procédé d'exécution de détection passive
CN105022038A (zh) * 2015-08-07 2015-11-04 武汉大学 一种基于形态分量分析的外辐射源雷达风场杂波抑制方法
CN109709523A (zh) * 2019-01-24 2019-05-03 电子科技大学 一种WiFi无源雷达的城市建筑环境杂波抑制方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2776438A1 (fr) * 1996-04-30 1999-09-24 Dassault Electronique Systeme de detection de mobiles, utilisant les emissions de telediffusion numerique d'un reseau d'emetteurs terrestres
US20020070796A1 (en) * 2000-10-17 2002-06-13 Olivier Gay-Bellile Multi-standard channel decoder
US20020198650A1 (en) * 2001-05-04 2002-12-26 Lockheed Martin Corporation System and method for wideband pre-detection signal processing for passive coherent location applications
US6778133B1 (en) * 2003-06-24 2004-08-17 Megadata Corporation Error correction of messages by a passive radar system
US20080088508A1 (en) * 1999-03-05 2008-04-17 Smith Alexander E Enhanced Passive Coherent Location Techniques to Track and Identify UAVs, UCAVs, MAVs, and Other Objects
US20080273080A1 (en) * 2007-05-04 2008-11-06 Legend Silicon Corp. Method and apparatus for decision feedback locationing using digtital telelvision signals

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2776438A1 (fr) * 1996-04-30 1999-09-24 Dassault Electronique Systeme de detection de mobiles, utilisant les emissions de telediffusion numerique d'un reseau d'emetteurs terrestres
US20080088508A1 (en) * 1999-03-05 2008-04-17 Smith Alexander E Enhanced Passive Coherent Location Techniques to Track and Identify UAVs, UCAVs, MAVs, and Other Objects
US20020070796A1 (en) * 2000-10-17 2002-06-13 Olivier Gay-Bellile Multi-standard channel decoder
US20020198650A1 (en) * 2001-05-04 2002-12-26 Lockheed Martin Corporation System and method for wideband pre-detection signal processing for passive coherent location applications
US6778133B1 (en) * 2003-06-24 2004-08-17 Megadata Corporation Error correction of messages by a passive radar system
US20080273080A1 (en) * 2007-05-04 2008-11-06 Legend Silicon Corp. Method and apparatus for decision feedback locationing using digtital telelvision signals

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102087354A (zh) * 2010-12-15 2011-06-08 哈尔滨工程大学 无源雷达分组ls-clean微弱目标检测方法
WO2015063488A1 (fr) * 2013-10-30 2015-05-07 Ucl Business Plc Appareil et procédé d'exécution de détection passive
US10288725B2 (en) 2013-10-30 2019-05-14 Ucl Business Plc Apparatus and method for performing passive sensing
CN104237859A (zh) * 2014-08-27 2014-12-24 武汉大学 利用gpu实现外辐射源雷达多通道时域杂波抑制的方法
CN104267375A (zh) * 2014-10-08 2015-01-07 武汉大学 一种外辐射源雷达网误差自配准方法
CN105022038A (zh) * 2015-08-07 2015-11-04 武汉大学 一种基于形态分量分析的外辐射源雷达风场杂波抑制方法
CN109709523A (zh) * 2019-01-24 2019-05-03 电子科技大学 一种WiFi无源雷达的城市建筑环境杂波抑制方法
CN109709523B (zh) * 2019-01-24 2020-06-19 电子科技大学 一种WiFi无源雷达的城市建筑环境杂波抑制方法

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