GB2318009A - Ground speed measurement using impulse radar - Google Patents

Ground speed measurement using impulse radar Download PDF

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Publication number
GB2318009A
GB2318009A GB9620825A GB9620825A GB2318009A GB 2318009 A GB2318009 A GB 2318009A GB 9620825 A GB9620825 A GB 9620825A GB 9620825 A GB9620825 A GB 9620825A GB 2318009 A GB2318009 A GB 2318009A
Authority
GB
United Kingdom
Prior art keywords
vehicle
ground speed
impulse radar
radar
signal
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.)
Withdrawn
Application number
GB9620825A
Other versions
GB9620825D0 (en
Inventor
Graeme Peter Smith
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.)
Ford Motor Co
Original Assignee
Ford Motor Co
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 Ford Motor Co filed Critical Ford Motor Co
Priority to GB9620825A priority Critical patent/GB2318009A/en
Publication of GB9620825D0 publication Critical patent/GB9620825D0/en
Publication of GB2318009A publication Critical patent/GB2318009A/en
Withdrawn legal-status Critical Current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
    • 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
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G01S13/60—Velocity or trajectory determination systems; Sense-of-movement determination systems wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track
    • 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
    • G01S13/0209—Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/9314—Parking operations

Landscapes

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

Abstract

A ground speed measuring system for a vehicle comprises at least one impulse radar transmitter for transmitting radio frequency pulses without a carrier wave (carrier-free) and at least one receiver to receive reflected signals from the environment surrounding the vehicle. The received reflections are integrated over a period of time to form a signal at audio frequency having a dominant frequency which is a function of the vehicle speed. The system can include four radar transmitters and receivers located at the corners of the vehicle which provide additional information such as collision warning or function as parking aids.

Description

VEHICLE GROUND SPEED MEASUREMENT Field of the Invention The invention relates to a vehicle ground speed measurement device.
The speedometer was one of the first measuring devices required in a motor vehicle and many different ground speed measurement systems have been developed over the years.
One widely used system uses FMCW radar sensors mounted upon a vehicle which receive reflected signals from the road, the road side and from objects within the vicinity of the vehicle. By measuring the Doppler shift of the received signal, the true ground speed of the vehicle can be calculated. Such a system can however prove expensive, since the circuitry involved can be costly.
Summary of the Invention According to the invention there is provided a ground speed measuring system comprising an impulse radar sensing system including at least one impulse radar transmitter transmitting a series of short radio frequency pulses without a carrier wave and at least one receiver to receive .reflected signals from the environment surrounding the vehicle, an integrator for integrating the received reflections over a time period to form a signal at audio frequency, means to measure the dominant frequency of the audio signal and to determine current vehicle speed as a function of the dominant frequency.
In this context the term 'impulse radar' is intended to encompass any radar signal of short radio frequency without a carrier wave, and includes radar sometimes referred to as 'broadband radar' Because the spectrum of the radiated signal is very broad, the radar cannot be said to operate at a particular frequency. By virtue of transmitting only a short pulse the reflection from the target arrives after a delay corresponding to the distance from the target. Integration of the signal over a time period can form a signal at audio frequency representative of reflections from the environment.
The reflected impulse radar waveform has a variable signature depending on the distance and radar cross section of reflectors within the radar field of view. It also has an audio component which has been shown to be variable and related to target velocity. A dominant frequency characteristic is apparent which is related to current vehicle speed.
The velocity related frequency shift can be used to determine true ground speed of the vehicle by monitoring the reflection from environment clutter in the road scene. Small radar reflections from the road and the roadside accumulate to give a dominant frequency characteristic of the returned signature.
Typically the means to determine current vehicle speed uses either digital signal processing techniques or Fast Fourier Transform circuitry. Such processors are commercially available and the choice will be readily apparent to the skilled addressee of the specification.
Preferably the received signal from the radar receiver is fed to gating means which sample the signal during a series of predetermined sampling periods, each period corresponding to the time taken for a signal to travel from the transmitter to a notional range shell and be reflected back to the receiver, such that the presence of a received signal within the period indicates the presence of an object within the notional range shell.
The advantage of using impulse radar for the ground speed measurement is that compact sensors which are easily packaged, are available, thus cutting the cost of the system. The circuitry involved in impulse radar is not expensive and this helps to reduce costs.
Moreover impulse radar may be used in a number of applications sensing objects in the vicinity of the vehicle, for example collision warning and parking aids. The sensors used for such applications can also be used for ground speed measurement, thus reducing hardware costs.
Preferably the system includes at least two radar transmitters and receivers, and more preferably four radar sensors are mounted, one at each corner of the vehicle. This provides a comprehensive multifunctional system.
The choice of circuitry to determine the vehicle speed from the integrated received signal will be apparent to the skilled addressee of the specification.

Claims (1)

  1. Claims
    1. A ground speed measuring system comprising an impulse radar sensing system including at least one impulse radar transmitter transmitting a series of short radio frequency pulses without a carrier wave and at least one receiver to receive reflected signals from the environment surrounding the vehicle, an integrator for integrating the received reflections over a time period to form a signal at audio frequency, means to measure the dominant frequency of the audio signal and to determine current vehicle speed as a function of the dominant frequency.
GB9620825A 1996-10-05 1996-10-05 Ground speed measurement using impulse radar Withdrawn GB2318009A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9620825A GB2318009A (en) 1996-10-05 1996-10-05 Ground speed measurement using impulse radar

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9620825A GB2318009A (en) 1996-10-05 1996-10-05 Ground speed measurement using impulse radar

Publications (2)

Publication Number Publication Date
GB9620825D0 GB9620825D0 (en) 1996-11-20
GB2318009A true GB2318009A (en) 1998-04-08

Family

ID=10801020

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9620825A Withdrawn GB2318009A (en) 1996-10-05 1996-10-05 Ground speed measurement using impulse radar

Country Status (1)

Country Link
GB (1) GB2318009A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7068211B2 (en) 2000-02-08 2006-06-27 Cambridge Consultants Limited Methods and apparatus for obtaining positional information

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4152701A (en) * 1978-04-20 1979-05-01 Sperry Rand Corporation Base band speed sensor
WO1994024579A1 (en) * 1993-04-12 1994-10-27 The Regents Of The University Of California Ultra-wideband radar motion sensor
US5381151A (en) * 1994-02-02 1995-01-10 Grumman Aerospace Corporation Signal processing for ultra-wideband impulse radar

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4152701A (en) * 1978-04-20 1979-05-01 Sperry Rand Corporation Base band speed sensor
WO1994024579A1 (en) * 1993-04-12 1994-10-27 The Regents Of The University Of California Ultra-wideband radar motion sensor
US5381151A (en) * 1994-02-02 1995-01-10 Grumman Aerospace Corporation Signal processing for ultra-wideband impulse radar

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7068211B2 (en) 2000-02-08 2006-06-27 Cambridge Consultants Limited Methods and apparatus for obtaining positional information
US7227493B2 (en) 2000-02-08 2007-06-05 Cambridge Consultants Limited Methods and apparatus for obtaining positional information

Also Published As

Publication number Publication date
GB9620825D0 (en) 1996-11-20

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)