WO2008040335A1 - Système radar destiné au balayage de l'environnement avec des moyens servant à la mesure de la ligne caractéristique d'un oscillateur - Google Patents

Système radar destiné au balayage de l'environnement avec des moyens servant à la mesure de la ligne caractéristique d'un oscillateur Download PDF

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Publication number
WO2008040335A1
WO2008040335A1 PCT/DE2007/001776 DE2007001776W WO2008040335A1 WO 2008040335 A1 WO2008040335 A1 WO 2008040335A1 DE 2007001776 W DE2007001776 W DE 2007001776W WO 2008040335 A1 WO2008040335 A1 WO 2008040335A1
Authority
WO
WIPO (PCT)
Prior art keywords
frequency
oscillator
signal
radar system
measurement
Prior art date
Application number
PCT/DE2007/001776
Other languages
German (de)
English (en)
Inventor
Markus Wintermantel
Arnold Herb
Original Assignee
Adc Automotive Distance Control Systems Gmbh
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 Adc Automotive Distance Control Systems Gmbh filed Critical Adc Automotive Distance Control Systems Gmbh
Priority to DE112007001665T priority Critical patent/DE112007001665A5/de
Publication of WO2008040335A1 publication Critical patent/WO2008040335A1/fr

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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
    • 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
    • G01S7/4004—Means for monitoring or calibrating of parts of a radar system
    • G01S7/4008—Means for monitoring or calibrating of parts of a radar system of transmitters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • 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
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal

Definitions

  • the invention relates to a radar system for environment detection with means for measuring an oscillator characteristic.
  • a system for environmental monitoring may e.g. be used in a motor vehicle, in which a driver assistance or safety function is provided.
  • a frequency modulated radar system is based on an oscillator which outputs a signal having a predetermined output frequency in response to an incoming control signal.
  • the dependence of these two parameters is described with a frequency characteristic of the oscillator.
  • the frequency characteristic must be measured very accurately in order to avoid measurement errors in the detection of environmental objects. Errors in the frequency modulation can lead to a blurred image of objects, whereby objects with a small backscatter cross section of objects with a larger backscatter cross section can be obscured. Further effects of errors in the frequency modulation may be interference lines and thus misdetections, as well as increased noise.
  • the frequency characteristic must be constantly updated to B. to be able to compensate for a change caused by a temperature drift.
  • One known method of measuring frequency characteristics is to count the number of zero crossings within a given measurement interval for a constant oscillator drive signal. This procedure is either inaccurate when a short measuring interval is selected, or very slowly if a long measuring interval is selected to increase the measuring accuracy.
  • the claimed radar system for detecting the surroundings with means for measuring an oscillator characteristic comprises transmitting means for the directed emission of transmission power, receiving means for the directed reception of transmission power reflected at objects and signal processing means for processing the received power.
  • the frequency of the transmission power is modulated by a corresponding control of a designated oscillator.
  • the oscillator is driven by a set of discrete control signal values. For at least a portion of these discrete control signal values, the output frequency of the oscillator is measured and a control signal output frequency characteristic is generated for the oscillator.
  • the measurement of the oscillator output frequency comprises a sampling of the oscillator output signal or a signal obtained therefrom by frequency division, optionally after suitable preprocessing, a windowing of the sampled signal and a frequency determination for the windowed signal by means of a spectral analysis. The measurement is performed for each one discrete control signal value.
  • the oscillator output frequency is controlled via a control signal only by "software."
  • the result of the software control beyond the possibility of the waveform of the transmission signal very easy to vary, for example, to dynamically adjust the frequency deviation and thus adjust the distance resolution the current environmental conditions, for example, the traffic conditions.
  • a discrete Fourier transform is used for spectral analysis and the output frequency of the oscillator is obtained by interpolation or estimation of the signal values between the discrete spectral lines taking into account the window function used.
  • the discrete Fourier transform is performed with a fast Fourier transform (FFT).
  • FFT fast Fourier transform
  • a voltage-controlled oscillator VCO is provided as an oscillator for modulating the transmission power.
  • VCO voltage-controlled oscillator
  • only the already measured control signal values of the oscillator characteristic curve are used for frequency modulation. Unmeasured control signal values, ie estimated or interpolated values, are not used for the generation of the transmission signal.
  • a signal path for detecting objects and a return measuring path for measuring the oscillator frequencies are provided.
  • the return measurement path is arranged separately from the signal path and comprises a frequency divider. In a preferred embodiment of the invention is during the detection of
  • the feedback path is deactivated so as not to disturb the detection of environment objects.
  • a further embodiment of the invention provides that the output signal of the frequency divider in the feedback path is changed in its frequency such that the detection of environmental objects is not disturbed or only to a small degree.
  • the frequency in the return measurement path is set so that the frequency ranges of the signals in the signal and return measurement path have little or no overlap. The same applies to the harmonics of the signals.
  • the frequency divider in the return measuring path is designed so that the frequency of the sampled signal is not in the Range of 1/2-f A , 1-f ⁇ , 3/2-f A , 2-f ⁇ , ..., where f A , the sampling frequency, since then an interpolation of the frequency-dependent power curve between the discrete frequency values not possible is.
  • a particular embodiment of the radar system provides a data processing unit with an upstream analog-to-digital converter.
  • the data processing unit is used to evaluate signals that occur in the signal path and return path.
  • switching means are provided, so that only one signal, either a signal from the signal path or a signal from the return measurement path, is forwarded to the data processing unit.
  • the same DFT is used for the evaluation of measurement signals for the detection of objects and of measurement signals for measuring the oscillator frequencies.
  • a preferred embodiment of the radar system provides that the output frequency of the oscillator is measured at least twice in at least one discrete oscillator drive and filtered via at least two measured values. This procedure increases the accuracy of the frequency determination.
  • discrete signal values for oscillator control are generated by a digital-to-analogue converter (DAC).
  • DAC digital-to-analogue converter
  • Oscillator output frequencies correspond. This avoids that a measurement of unused measured values, extends the entire measurement time.
  • the detection of objects and the measurement of the oscillator frequencies is carried out at a substantially identical repetition rate. That the oscillator drive values used for
  • Ramp generation needed to be measured in one or a few cycles. In this way, it is ensured that a respective current characteristic is used for controlling the oscillator, so that rapidly changing environmental influences such as temperature changes, the accuracy of the radar system do not negatively influence. In order to reduce the measuring time, only one part of the characteristic curve can be measured before a detection of objects, and another part before the subsequent detection of objects and so on.
  • Fig. 1 Block diagram of a radar system with means for measuring an oscillator
  • Fig. 2 sampled oscillator signal from the remindmesspfad
  • Fig. 3 Spectrum of the sampled return measurement signal
  • Fig. 4 frequency-dependent power spectrum of the oscillator in the return path
  • Fig.1 a block diagram of a radar system is shown, which is all essential
  • a frequency-modulated transmission signal is generated, which is supplied via a coupler structure K to an antenna A.
  • the oscillator signal is fed to a mixer M, where it is mixed with the received signal.
  • the output of the mixer is filtered in a bandpass filter.
  • the feedback path R includes a frequency divider Kl and a bandpass filter BP. Feedback path and signal path are connected via a multiplexer MUX with a digital signal processing unit SP.
  • the signal processing unit with an analog to digital converter is connected upstream.
  • the transmission signal used is a sequence of linear frequency ramps whose frequency deviation per unit of time is so great that the difference frequency between the transmission signal and the reception signal depends almost exclusively on the transit time and thus on the distance to the object at which the reflection takes place.
  • the difference frequency depends only to a much smaller extent on the relative speed.
  • a feedback path R is provided.
  • the oscillator signal is digitized directly and then the frequency is determined.
  • a frequency divider, a bandpass filter and a multiplexer are necessary for this purpose. This path is active during the transmission pauses. During measurement of ambient objects (transmit power is emitted and received), the return measurement signal is deactivated in order to avoid coupling to the signal path.
  • the VCO drive voltage is gradually increased via a DAC (digital-to-analog converter), whereby a control value generated by the DAC for the measurement time t mess is kept constant.
  • Oscillator drive values are measured, for example, before each measurement of surrounding objects, in which exactly these control signals are used.
  • a further embodiment of the invention provides that the measurement of the oscillator drive values is distributed over a plurality of measurement times, a measurement time for determining the oscillator characteristic curve each having a measurement time for detecting Environment objects alternate. It is z. For example, before measuring ambient objects, they measure half of the control values and before the subsequent measurement of ambient objects, they measure the other half of the control values. Accordingly, one-third or one-fourth of the control signals can also be measured before each measuring time for detecting objects. In this way, the total measuring time is shortened.
  • frequencies that are measured at different times at the same oscillator drive value are filtered over time in a further exemplary embodiment.
  • Oscillator output signal can be determined.
  • the digitized signals are multiplied by a suitable window function and then an FFT is performed.
  • the same FFT as in the target processing can be used, which offers a great advantage, especially when implementing the data evaluation on an FPGA (Field Programmable Gate Array).
  • the oscillator frequency can be read directly.
  • the waveform is given by the spectrum of the window function.
  • FIG. 4 plots the power of a return measurement signal versus frequency.
  • the lines indicate the power values for the discrete frequencies.
  • the interpolation is e.g. using values stored in the data evaluation unit (lookup tables) or a
  • the interpolation is first computed on a FPGA in a coarse grid and then more accurately computed on a microcontroller unit (MCU) by means of a correction function.
  • MCU microcontroller unit
  • a bandpass filter BP is arranged in the back measuring path after the frequency divider Kl.
  • the bandpass filter BP is designed so that the
  • the divider factor of the frequency divider Ki and the sampling frequency are tuned to one another such that the frequency of the
  • the windowing function is suitable to choose, so that for the resulting relevant frequency ranges in which the power peaks can come to lie, the spectrum of the window has already decayed so far that the power peaks no longer influence each other.
  • a set of signal control values can be calculated with which the desired function for frequency modulation can be realized, for example a linear frequency ramp.

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

L'invention concerne un système radar destiné au balayage de l'environnement, dont la puissance d'émission a une fréquence modulée par des excitations correspondantes d'un oscillateur qui est excité par un ensemble de valeurs de signaux de commande discrètes. Ce système radar est conçu de manière à ce que la fréquence de l'oscillateur soit mesurée, au moins pour une partie de ces valeurs de signaux de commande discrètes. La mesure de la fréquence comprend une lecture du signal de l'oscillateur ou d'un signal obtenu par division de fréquence et une détermination de fréquence du signal lu par analyse spectrale.
PCT/DE2007/001776 2006-10-06 2007-10-05 Système radar destiné au balayage de l'environnement avec des moyens servant à la mesure de la ligne caractéristique d'un oscillateur WO2008040335A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112007001665T DE112007001665A5 (de) 2006-10-06 2007-10-05 Radarsystem zur Umfelderfassung mit Mitteln zur Vermessung der Oszillatokennlinie

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102006047758 2006-10-06
DE102006047758.8 2006-10-06

Publications (1)

Publication Number Publication Date
WO2008040335A1 true WO2008040335A1 (fr) 2008-04-10

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PCT/DE2007/001776 WO2008040335A1 (fr) 2006-10-06 2007-10-05 Système radar destiné au balayage de l'environnement avec des moyens servant à la mesure de la ligne caractéristique d'un oscillateur

Country Status (2)

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DE (1) DE112007001665A5 (fr)
WO (1) WO2008040335A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103248361A (zh) * 2012-02-10 2013-08-14 英飞凌科技股份有限公司 具有可控振荡器的电路
CN110651197A (zh) * 2017-05-05 2020-01-03 康蒂-特米克微电子有限公司 具有监控同类发射信号序列频率位置的功能的雷达系统

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5291081A (en) * 1991-11-13 1994-03-01 Kokusai Denshin Denwa Co., Ltd. Apparatus for detection of non-modulated signal and frequency acquisition
EP0647857A1 (fr) * 1993-10-06 1995-04-12 Daimler-Benz Aerospace Aktiengesellschaft Radar à haute précision pour mesures de distance
DE19632889A1 (de) * 1996-08-16 1998-02-19 Bosch Gmbh Robert Radarsystem mit einem frequenzmodulierten Sendesignal
WO1998038524A1 (fr) * 1997-02-28 1998-09-03 Siemens Aktiengesellschaft Procede pour le fonctionnement d'un systeme detecteur, et systeme detecteur
EP0887658A1 (fr) * 1997-06-27 1998-12-30 Daimler-Benz Aerospace Aktiengesellschaft Jauge radar de niveau
WO2000035076A1 (fr) * 1998-12-10 2000-06-15 Siemens Aktiengesellschaft Dispositif de correction d'oscillateurs a tension variable de non-linearite d'un systeme radar fmcw
US6317074B1 (en) * 2000-06-15 2001-11-13 Alliant Techsystems Inc. High range resolution radar through non-uniform sampling
US6373427B1 (en) * 1997-08-11 2002-04-16 Mikrowellen-Technologie Und Sensoren Gmbh Radar distance measuring device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5291081A (en) * 1991-11-13 1994-03-01 Kokusai Denshin Denwa Co., Ltd. Apparatus for detection of non-modulated signal and frequency acquisition
EP0647857A1 (fr) * 1993-10-06 1995-04-12 Daimler-Benz Aerospace Aktiengesellschaft Radar à haute précision pour mesures de distance
DE19632889A1 (de) * 1996-08-16 1998-02-19 Bosch Gmbh Robert Radarsystem mit einem frequenzmodulierten Sendesignal
WO1998038524A1 (fr) * 1997-02-28 1998-09-03 Siemens Aktiengesellschaft Procede pour le fonctionnement d'un systeme detecteur, et systeme detecteur
EP0887658A1 (fr) * 1997-06-27 1998-12-30 Daimler-Benz Aerospace Aktiengesellschaft Jauge radar de niveau
US6373427B1 (en) * 1997-08-11 2002-04-16 Mikrowellen-Technologie Und Sensoren Gmbh Radar distance measuring device
WO2000035076A1 (fr) * 1998-12-10 2000-06-15 Siemens Aktiengesellschaft Dispositif de correction d'oscillateurs a tension variable de non-linearite d'un systeme radar fmcw
US6317074B1 (en) * 2000-06-15 2001-11-13 Alliant Techsystems Inc. High range resolution radar through non-uniform sampling

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103248361A (zh) * 2012-02-10 2013-08-14 英飞凌科技股份有限公司 具有可控振荡器的电路
US8598926B2 (en) 2012-02-10 2013-12-03 Infineon Technologies Ag Electrical circuit having a controllable oscillator
CN110651197A (zh) * 2017-05-05 2020-01-03 康蒂-特米克微电子有限公司 具有监控同类发射信号序列频率位置的功能的雷达系统
CN110651197B (zh) * 2017-05-05 2023-12-26 康蒂-特米克微电子有限公司 具有监控同类发射信号序列频率位置的功能的雷达系统

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