Multiple input multiple output (MIMO) frequency-modulated continuous-wave (FMCW) radar system

Patent metadata

Field	Value
Publication number	US-11693106-B2
Application number	US-201916675574-A
Country	US
Kind code	B2
Filing date	Nov 6, 2019
Priority date	Nov 8, 2018
Publication date	Jul 4, 2023
Grant date	Jul 4, 2023

Abstract

Methods for detecting radar targets are provided. According to one exemplary embodiment, the method includes providing a digital radar signal having a sequence of signal segments. Each signal segment of the sequence is respectively associated with a chirp of a transmitted RF radar signal. The method further includes detecting one or more radar targets based on a first subsequence of successive signal segments of the sequence. For each detected radar target, a distance value and a velocity value are determined. If a group of radar targets having overlapping signal components has been detected, a respective spectral value is calculated for each radar target of the group of radar targets based on a second subsequence of the sequence of signal segments and further based on the velocity values ascertained for the group of radar targets.

First claim

What is claimed is:

1. A method, comprising:
transmitting a sequence of radio frequency (RF) chirps via at least one of a first transmission channel and a second transmission channel, including transmitting a first subsequence of successive chirps and a second subsequence of successive chirps;
generating, by a reception channel, a digital radar signal having a sequence of signal segments from chirp echoes corresponding to the sequence of RF chirps, wherein each signal segment of the sequence is respectively associated with a different chirp of the sequence of RF chirps;
generating a range-Doppler map based only on a first subsequence of successive signal segments of the sequence of signal segments, wherein the first subsequence of successive signal segments correspond to the first subsequence of successive chirps;
detecting radar targets in the range-Doppler map, including determining a distance value and a velocity value for each detected radar target from the range-Doppler map;
ascertaining whether the detected radar targets comprise a group of radar targets having overlapping signal components in a distance dimension of the range-Doppler map; and
in response to detecting the group of radar targets having the overlapping signal components, calculating a spectral value for each radar target of the group of radar targets having the overlapping signal components based on a second subsequence of successive signal segments of the sequence of signal segments and based on velocity values, ascertained from the range-Doppler map, that correspond to the radar targets of the group of radar targets, wherein the second subsequence of successive signal segments correspond to the second subsequence of successive chirps,
wherein the second subsequence of successive chirps has a smaller number of chirps than the first subsequence of successive chirps.

2. The method as recited in claim 1 , wherein the calculation of the spectral value for each radar target of the group of radar targets comprises:
transforming the second subsequence of successive signal segments into a frequency domain in order to obtain corresponding spectra;
extracting values from a frequency bin of the obtained corresponding spectra that is associated with the group of radar targets; and
estimating a spectral value for each radar target of the group of radar targets based on the extracted values.

3. The method as recited in claim 2 , wherein the estimation of the spectral value for each radar target of the group of radar targets further comprises:
calculating an approximate solution for an overdetermined equation system using a coefficient matrix that is dependent on the velocity values ascertained for the group of radar targets, and using a vector of input values that correspond to the extracted values.

4. The method as recited in claim 1 , further comprising:
calculating the spectral value for each radar target of the group of radar targets based on a third subsequence of successive signal segments of the sequence of signal segments and further based on the distance values and the velocity values ascertained for the group of radar targets from the range-Doppler map,
wherein the second subsequence of successive signal segments are associated with the second subsequence of successive chirps emitted via the first transmission channel, and the third subsequence of successive signal segments are associated with a third subsequence of successive chirps emitted via the second transmission channel.

5. The method as recited in claim 4 , wherein the second subsequence and the third subsequence are of equal length.

6. The method as recited in claim 1 , wherein generating the digital radar signal comprises:
receiving an RF radar signal comprising the chirp echoes in a reception channel and down-converting the received RF radar signal; and
generating the digital radar signal based on the down-converted RF radar signal.

7. The method as recited in claim 6 , further comprising:
if the group of radar targets having the overlapping signal components is detected, repeating calculating of a further spectral value for each radar target of the group of radar targets for digital radar signals from different reception channels.

8. The method as recited in claim 7 , further comprising:
calculating angles of azimuth of radar targets of the group of radar targets based on the calculated further spectral values.

9. The method as recited in claim 1 , wherein the first subsequence of successive signal segments is associated with the first subsequence of successive chirps emitted via the first transmission channel, and
wherein the second subsequence of successive signal segments is associated with the first subsequence of successive chirps emitted via the second transmission channel.

10. A system, comprising:
a radar transceiver having a reception channel, a first transmission channel, and a second transmission channel,
wherein the radar transceiver is configured to transmit a sequence of radio frequency (RF) chirps via at least one of the first transmission channel and the second transmission channel, including transmitting a first subsequence of successive chirps and transmitting a second subsequence of successive chirps,
wherein the reception channel is configured to generate a digital radar signal having a sequence of signal segments from chirp echoes corresponding to the sequence of RF chirps, wherein each signal segment of the sequence of signal segments is respectively associated with a different chirp of the sequence of RF chirps; and
at least one processor configured to:
generate a range-Doppler map based only on a first subsequence of successive signal segments of the sequence of signal segments, wherein the first subsequence of successive signal segments are associated with the first subsequence of successive chirps;
detect radar targets in the range-Doppler map, including determining a distance value and a velocity value for each detected radar target from the range-Doppler map;
ascertain whether the detected radar targets comprise a group of radar targets having overlapping signal components in a distance dimension of the range-Doppler map; and
in response to detecting the group of radar targets having the overlapping signal components, calculate a spectral value for each radar target of the group of radar targets having the overlapping signal components based on a second subsequence of successive signal segments of the sequence of signal segments and based on velocity values, ascertained from the range-Doppler map, that correspond to the radar targets of the group of radar targets, wherein the second subsequence of successive signal segments are associated with the second subsequence of successive chirps,
wherein the second subsequence of successive chirps has a smaller number of chirps than the first subsequence of successive chirps.

11. The system as recited in claim 10 ,
wherein, in order to detect the radar targets, the at least one processor is configured to use the digital radar signal as a basis for calculating the range-Doppler map and determine in the range-Doppler map a local maxima pointing to corresponding radar targets, and
wherein, in order to ascertain whether the detected radar targets comprise the group of radar targets having overlapping signal components, the at least one processor is configured to determine whether the detected radar targets have signal components in a same frequency bin of the range-Doppler map, wherein the detected radar targets that have the signal components in the same frequency bin of the range-Doppler map are grouped into the group of radar targets.

12. The sys

Assignees

• Infineon Technologies Ag

Inventors

• Lang Oliver
• Gerstmair Michael
• Melzer Alexander
• Schmid Christian

Classifications

• H04B7/0413

  MIMO systems · CPC title

• G01S7/415

  Identification of targets based on measurements of movement associated with the target · CPC title

• G01S13/584 Primary

  adapted for simultaneous range and velocity measurements · CPC title

• G01S13/48 Primary

  using multiple beams at emission or reception · CPC title

• G01S13/91

  for traffic control (G01S13/93 takes precedence) · CPC title