Radar method and device for carrying out the method

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, and
• alerting a driver of the vehicle if a predetermined indication threshold for the distance and the relative speed is exceeded.