Communications: directive radio wave systems and devices (e.g. – Return signal controls external device – Radar mounted on and controls land vehicle
Reexamination Certificate
1999-05-20
2001-07-24
Gregory, Bernarr E. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Return signal controls external device
Radar mounted on and controls land vehicle
C342S071000, C342S089000, C342S092000, C342S093000, C342S104000, C342S105000, C342S118000, C342S128000, C342S159000, C342S175000, C342S195000, C342S196000
Reexamination Certificate
active
06266004
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority of German Patent Application No. 198 22 622.5 filed May 20, 1998.
BACKGROUND OF THE INVENTION
The invention relates to a radar method used in a motor vehicle for an automatic, intelligent traffic flow control (AICC).
The characteristics and design of known radar devices in motor vehicles are essentially defined by the use of pulse radar. The known systems make use of involved and cost-intensive multipath systems to detect several measuring variables,.
A high-resolution radar method is described in the previously filed German patent application 197 32 509.2, which is based on a frequency-modulated, continuous-wave (FM-CW) method with saw-tooth modulation to achieve a simultaneous resolution of the radar scene with respect to distance and relative speed. With this method, the radar echo is mixed at the transmitting reference to form the baseband signal. The method is distinguished in that:
The baseband signal of each modulation period is digitized in an analog/digital converter and is converted to distance/time values by means of a N-point Fourier Transformation;
this conversion is repeated for M modulation periods that follow successively in time;
the determined distance values for each modulation period are stored in a line, assigned to the respective modulation period, of a two-dimensional data memory;
the stored distance/time values are subjected in columns to an M-point Fourier Transformation to form relative speed values and that a distance/speed matrix of the observed radar scene is generated in this way.
This method provides for a frequency-dependent and thus also distance-dependent level compensation in the analog portion of the radar sensor, or a frequency limitation of the baseband signals to higher frequencies by utilizing an anti-aliasing filter that is connected in series before the A/D converter. One embodiment of the method provides that of the N distance/time values, determined with the N-pointed Fourier Transformation, only N
R
<N/2 values are stored and processed for the subsequent signal processing. The Fourier Transformations used (e.g. the Fast Fourier Transformation (FFT)) operate with suitable data windows to reduce minor lobes to a preset value for the resolution cells of the distance/speed matrix.
SUMMARY OF THE INVENTION
It is the object of the invention to create a cost-effective radar method for an AICC in a motor vehicle, which makes it possible to have radar systems using little space. The radar method is designed to detect the distance, the relative speed and the angle to preceding motor vehicles and to process these values for use in an AICC.
The solution according to the invention is provided by a radar method used in a motor vehicle for an automatic, intelligent communication control (AICC), characterized in that a FM-CW method is used, that when using an A/D converter
5
with 8-bit resolution, the necessary dynamic is generated with a level switchover, that the R, V information is generated in FFTs
6
with blocked R and V FFTs, that the useful signals are separated from the noise in a detection
7
by means of a R-dependent, adaptive CFAR threshold, that in a track formation
8
the detection is assigned directly to the tracks, and that in the process, the assigning of a detection i to a track j is computed as probability r(i,j). The crosstalk noise from the transmitting range and the receiving range, which is standard for short distances, is compensated in two stages.
REFERENCES:
patent: 5481268 (1996-01-01), Higgins
patent: 5508706 (1996-04-01), Core et al.
patent: 5587713 (1996-12-01), Pfizenmaier et al.
patent: 4243527 (1996-01-01), None
patent: WO 9514939 (1995-06-01), None
Jacobi Wieland
Mann Dieter
Pannert Wolfram
Wittekind Wolfgang
Daimler-Chrysler AG
Gregory Bernarr E.
Kinberg Robert
Venable
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