Radar method and device for carrying out the method
First Claim
1. A radar method for vehicles employing at least one radar beam, which comprises:
- determining object frequencies assigned to target objects per measurement cycle from maxima contained in a frequency spectra derived from the object frequencies in a digital signal processor, by;
separately subjecting digitized and recorded samples received during two modulation phases in each modulation cycle of mixed signals formed from transmitted and received signals to a fast Fourier transformation in successive measurement cycles per radar beam,and including a modulation cycle formed from a rising and a falling modulation phase of the radar signal and a subsequent evaluation pause for received echo signals in each measurement cycle,storing the object frequencies over a number of measurement cycles,forming object tracks separated according to rising and falling modulation phases from the stored object frequencies for each target object,describing a previous time-domain behavior of the object frequencies with the object tracks,forming estimated values for the object frequencies to be expected in the next measurement cycle from a previous behavior of the object tracks,calculating an error from the object frequencies and from the estimated values obtained from the object tracks, assigning object frequency pairs having the respectively smallest error to one another after the calculation of the error, and calculating correct values for a distance and a relative speed of at least one target object from the pairs,determining and storing a data set containing distance and relative speed data for at least one target object,filtering the distance and relative speed data,determining a turn radius and a speed of the vehicle,determining which target objects are located in a lane occupied by the vehicle by using the distance and the relative speed of the target object, as well as the speed and turn radius of the vehicle, and determining at least the most dangerous target object therefrom, andalerting a driver of the vehicle if a predetermined indication threshold for the distance and the relative speed is exceeded.
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Accused Products
Abstract
A radar method and a device for carrying out the method include estimating an azimuth angle of each target object from determined variables of distance or range, relative speed and relative acceleration after Kalman filtering and separating out target objects having a physically impossible behavior (tracking and prediction). That is used to determine which target objects are located on a roadway occupied by a vehicle and which are the most dangerous thereof. Indication, warning or action thresholds are determined as a function of driving behavior of the driver, road conditions and weather conditions. Indication, warning or action signals (in the brakes, throttle valve or gear shift of the vehicle) result if the thresholds are exceeded or undershot by the range, the relative speed and the relative acceleration.
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Citations
25 Claims
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1. A radar method for vehicles employing at least one radar beam, which comprises:
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determining object frequencies assigned to target objects per measurement cycle from maxima contained in a frequency spectra derived from the object frequencies in a digital signal processor, by; separately subjecting digitized and recorded samples received during two modulation phases in each modulation cycle of mixed signals formed from transmitted and received signals to a fast Fourier transformation in successive measurement cycles per radar beam, and including a modulation cycle formed from a rising and a falling modulation phase of the radar signal and a subsequent evaluation pause for received echo signals in each measurement cycle, storing the object frequencies over a number of measurement cycles, forming object tracks separated according to rising and falling modulation phases from the stored object frequencies for each target object, describing a previous time-domain behavior of the object frequencies with the object tracks, forming estimated values for the object frequencies to be expected in the next measurement cycle from a previous behavior of the object tracks, calculating an error from the object frequencies and from the estimated values obtained from the object tracks, assigning object frequency pairs having the respectively smallest error to one another after the calculation of the error, and calculating correct values for a distance and a relative speed of at least one target object from the pairs, determining and storing a data set containing distance and relative speed data for at least one target object, filtering the distance and relative speed data, determining a turn radius and a speed of the vehicle, determining which target objects are located in a lane occupied by the vehicle by using the distance and the relative speed of the target object, as well as the speed and turn radius of the vehicle, and determining at least the most dangerous target object therefrom, and alerting a driver of the vehicle if a predetermined indication threshold for the distance and the relative speed is exceeded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A radar device for vehicles employing at least one radar beam, comprising:
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a digital signal processor producing triangular-waveform digital modulation signals; an interface module having a D/A converter converting the digital modulation signals into analog signals; a radar front end processing the analog signals to form modulated radar signals; at least one antenna transmitting and receiving the modulated radar signals; a mixing and filtering device for producing mixed signals from the transmitted and received signals; said interface module having an A/D converter converting the mixed signals into digital signals and supplying the digital signals to said signal processor for further processing; a sensor interface for supplying signals to said signal processor; an interface unit for supplying control signals from said signal processor to other units of the vehicle; a control line connected from said signal processor to said radar front end for carrying digital control signals from said signal processor to control said at least one transmitting and receiving antenna; and an indication or warning device being controlled by control signals from said signal processor. - View Dependent Claims (21, 22, 23, 24, 25)
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Specification