Method for detecting an object and angle-resolving fmcw radar sensor system

A method for detecting an object using an angle-resolving FMCW radar sensor, the method comprising the following steps:

• generating an at least three-dimensional spectrum with a distance dimension, a Doppler dimension indicating a relative velocity of objects, and an angular dimension, based on received signals from multiple different receiving channels of the radar sensor, wherein the radar sensor undersamples in the Doppler dimension and the spectrum in the Doppler dimension is therefore incomplete and ambiguous;
• using a frequency modulation scheme with a plurality of interleaved sequences of temporally equidistant frequency ramps to resolve the ambiguities;
• for each of a plurality of velocity hypotheses, (i) modeling a velocity-dependent phase offset between the received signals obtained for the different sequences based on of known time offsets between the frequency ramps belonging to different sequences, and (ii) comparing the modeled phase offset with the measured phase offset;
• during the comparison, evaluating angle-dependent phase offsets of the different receiving channels together with the velocity-dependent phase offsets and reconstructing a complete and unambiguous spectrum;
• and
• carrying out the object detection based on the reconstructed spectrum.

A radar sensor, comprising:

• a digital processor unit configured for detecting an object using an angle-resolving FMCW radar sensor, the digital processor unit configured to:
• generate an at least three-dimensional spectrum with a distance dimension, a Doppler dimension indicating a relative velocity of objects, and an angular dimension, based on received signals from multiple different receiving channels of the radar sensor, wherein the radar sensor undersamples in the Doppler dimension and the spectrum in the Doppler dimension is therefore incomplete and ambiguous,
• use a frequency modulation scheme with a plurality of interleaved sequences of temporally equidistant frequency ramps to resolve the ambiguities,
• for each of a plurality of velocity hypotheses, (i) model a velocity-dependent phase offset between the received signals obtained for the different sequences based on of known time offsets between the frequency ramps belonging to different sequences, and (ii) compare the modeled phase offset with the measured phase offset,
• during the comparison, evaluate angle-dependent phase offsets of the different receiving channels together with the velocity-dependent phase offsets and reconstructing a complete and unambiguous spectrum, and
• carry out the object detection based on the reconstructed spectrum.

A radar sensor system, comprising:

• an angle-resolving FMCW radar sensor including an internal processor unit;
• and
• an external processor unit;
• wherein the radar sensor system is configured to implement, partly in the internal processor unit and partly in the external processor unit, a method for detecting an object using the angle-resolving FMCW radar sensor, the method including:
• generating an at least three-dimensional spectrum with a distance dimension, a Doppler dimension indicating a relative velocity of objects, and an angular dimension, based on received signals from multiple different receiving channels of the radar sensor, wherein the radar sensor undersamples in the Doppler dimension and the spectrum in the Doppler dimension is therefore incomplete and ambiguous,
• using a frequency modulation scheme with a plurality of interleaved sequences of temporally equidistant frequency ramps to resolve the ambiguities,
• for each of a plurality of velocity hypotheses, (i) modeling a velocity-dependent phase offset between the received signals obtained for the different sequences based on of known time offsets between the frequency ramps belonging to different sequences, and (ii) comparing the modeled phase offset with the measured phase offset,
• during the comparison, evaluating angle-dependent phase offsets of the different receiving channels together with the velocity-dependent phase offsets and reconstructing a complete and unambiguous spectrum, and
• carrying out the object detection based on the reconstructed spectrum.

A radar sensor system, comprising:

• an angle-resolving FMCW radar sensor;
• and
• an external processor unit;
• wherein the radar sensor system is configured to implement in the external processor unit, a method for detecting an object using the angle-resolving FMCW radar sensor, the method comprising:
• generating an at least three-dimensional spectrum with a distance dimension, a Doppler dimension indicating a relative velocity of objects, and an angular dimension, based on received signals from multiple different receiving channels of the radar sensor, wherein the radar sensor undersamples in the Doppler dimension and the spectrum in the Doppler dimension is therefore incomplete and ambiguous,
• using a frequency modulation scheme with a plurality of interleaved sequences of temporally equidistant frequency ramps to resolve the ambiguities,
• for each of a plurality of velocity hypotheses, (i) modeling a velocity-dependent phase offset between the received signals obtained for the different sequences based on of known time offsets between the frequency ramps belonging to different sequences, and (ii) comparing the modeled phase offset with the measured phase offset,
• during the comparison, evaluating angle-dependent phase offsets of the different receiving channels together with the velocity-dependent phase offsets and reconstructing a complete and unambiguous spectrum, and
• carrying out the object detection based on the reconstructed spectrum.