Estimation of transverse velocities or cartesian velocities of point targets with a radar sensor

A radar sensor for a motor vehicle, comprising:

• an antenna system having a transmitting antenna and a plurality of receiving antennas arranged at different positions than one another on a same substrate so that respective center positions, which are all measured in a single direction between (i) each respective one of the plurality of receiving antennas and (ii) the transmitting antenna, all differ from one another, the transmitting antenna being a same transmitting antenna at different distances from which different ones of the receiving antennas are arranged;
• and
• a processor, wherein the processor is configured to, for a single transmission modulation cycle of a signal transmission by the same transmitting antenna:
• obtain, by each of the plurality of receiving antennas, different respective echo signals generated by a reflection, from the radar target, of the signal transmission, the differences between the respective echo signals being a function of the differences in the respective center positions of the plurality of receiving antennas;
• due to differences in the respective echo signals determine a plurality of different values of a radial speed of the radar target without obtaining corresponding values of a tangential speed, each of the plurality of different values of the radial speed being determined based on a different respective one of the obtained echo signals;
• and
• estimate the actual speed of the radar target based on a combination of the determined plurality of different values of the radial speed of the radar target determined for the single transmission modulation cycle without use of any radial speeds determined in any other transmission modulation cycle, the estimated actual speed including an estimated tangential speed of the radar target relative to the radar sensor.