Method and apparatus for emitting electromagnetic radiation and receiving partial radiation reflected by the objects

Patent metadata

Field	Value
Publication number	US-11474226-B2
Application number	US-202017009396-A
Country	US
Kind code	B2
Filing date	Sep 1, 2020
Priority date	Sep 27, 2019
Publication date	Oct 18, 2022
Grant date	Oct 18, 2022

Abstract

An apparatus for emitting electromagnetic radiation and receiving partial radiation reflected by objects, and determines the instantaneous performance of its system detection. The apparatus includes a device for emitting a frequency-modulated transmit signal that has at least two signal sequences which have ramps, each succeeding one another in the frequency characteristic, with gaps in between, the signal sequences being interleaved with each other with a predetermined time offset so that in each case a first ramp of each of the signal sequences is output before a second ramp of one of the at least two signal sequences is output. The apparatus includes a mixer, an analog-to-digital converter, a transform device, and a device for detecting phase noise. The phase changes of the receive signals are compared over all two-dimensional spectra to a precalculated model, and the cause of the phase noise is ascertained with the aid of predetermined criteria.

First claim

What is claimed is:

1. A method for determining an instantaneous performance of a radar system that includes an apparatus for emitting electromagnetic radiation and receiving partial radiation reflected by objects having a frequency-modulated transmit signal, which has at least two signal sequences, that have ramps, each of the ramps succeeding one another in a frequency characteristic, with gaps in between, the at least two signal sequences being interleaved with each other with a predetermined time offset in such a way that in each case a first ramp of each of the at least two signal sequences is output before a second ramp of one of the at least two signal sequences is output, the apparatus further including a mixer mixing a frequency-modulated transmit signal with a signal received by at least one antenna of the radar system, a mixed product of the mixer being converted from analog to digital, a digitized signal of each of the at least two signal sequences being transformed into a two-dimensional spectrum, and phase noise being detected in each of the two-dimensional spectra, the method comprising:
in a first step, comparing phase changes of received reflected signals over all two-dimensional spectra to a precalculated model; and
in a second step, ascertaining a cause of the phase noise using one or more predetermined criteria.

2. The method as recited in claim 1 , wherein the instantaneous performance of the radar system includes: (i) recognition of sensor blindness due to an absorptive radome coating, and/or (ii) recognition of weaker detection capability for weak targets, accompanied by simultaneous detection of strong targets.

3. The method as recited in claim 2 , wherein upon recognition of reduced detection performance for weaker targets in certain distance regions of the sensor, the certain distance regions are provided to downstream driver assistance functions.

4. The method as recited claim 1 , wherein the precalculated model specifies anticipated phase differences for each point of the two-dimensional spectrum and compares measured phase differences to the anticipated differences.

5. The method as recited in claim 4 , wherein the comparison of the measured phase differences and the anticipated differences is determined using a correlation.

6. The method as recited in claim 4 , wherein phase noise is present when a value of the measured phase differences differs from an anticipated value of the anticipated differences by more than a permissible threshold value.

7. The method as recited in claim 6 , wherein the permissible threshold value is determined for each point of the two-dimensional spectrum, and the threshold permissible threshold value is a function of a signal-to-noise ratio of each point in the two-dimensional spectrum.

8. The method as recited in claim 4 , wherein the phase differences are compared only in regions of the two-dimensional spectra in which objects are detected.

9. The method as recited in claim 1 , wherein the one or more criteria, based on which the cause of the phase noise is determined, includes, during one measuring cycle:
a number of detections with poor speed quality, and/or
a total number of detections, and/or
a maximum signal-to-noise ratio of all valid targets, and/or
a relative position of the detections with poor speed quality with respect to each other as well as a position relative to the strongest valid target.

10. The method as recited in claim 1 , wherein regions of the two-dimensional spectra in which increased phase noise is determined are marked as unreliable for recognition of absorptive blindness.

11. The method as recited in claim 1 , wherein detections with micro-Doppler effect are distinguished from “real” phase noise based on a relative position of the detections having poor speed quality with respect to each other and with respect to a strongest valid target.

12. The method as recited in claim 1 , wherein the two-dimensional spectrum is a speed-distance spectrum.

13. A non-transitory machine-readable storage medium on which is stored a computer program for determining an instantaneous performance of a radar system that includes an apparatus for emitting electromagnetic radiation and receiving partial radiation reflected by objects having a frequency-modulated transmit signal, which has at least two signal sequences, that have ramps, each of the ramps succeeding one another in a frequency characteristic, with gaps in between, the at least two signal sequences being interleaved with each other with a predetermined time offset in such a way that in each case a first ramp of each of the at least two signal sequences is output before a second ramp of one of the at least two signal sequences is output, the apparatus further including a mixer mixing a frequency-modulated transmit signal with a signal received by at least one antenna of the radar system, a mixed product of the mixer being converted from analog to digital, a digitized signal of each of the at least two signal sequences being transformed into a two-dimensional spectrum, and phase noise being detected in each of the two-dimensional spectra, the computer program, when executed by a computer, causing the computer to perform:
in a first step, comparing phase changes of received signals over all two-dimensional spectra to a precalculated model; and
in a second step, ascertaining a cause of the phase noise using one or more predetermined criteria.

14. An apparatus for emitting electromagnetic radiation and receiving partial radiation reflected by objects, which is able to determine the instantaneous performance of its system detection, comprising:
a device configured to emit a frequency-modulated transmit signal which has at least two signal sequences, that have ramps, each succeeding one another in the frequency characteristic, with gaps in between,
the at least two signal sequences being interleaved with each other with a predetermined time offset in such a way that in each case a first ramp of each of the at least two signal sequences is output before a second ramp of one of the at least two signal sequences is output;
a mixer configured to mix the frequency-modulated transmit signal with a signal received by at least one antenna of a radar system;
an analog-to-digital converter configured to digitize a mixed product of the mixer;
a device configured to transform the digitized signal of each one of the at least two signal sequences into a two-dimensional spectrum;
a device configured to detect phase noise in each of the two-dimensional spectra; and
a device configured to, in a first step, compare phase changes of received reflected signals over all two-dimensional spectra to a precalculated model, and in a second step, ascertain a cause of phase noise using one or more predetermined criteria.

Assignees

• Bosch Gmbh Robert

Inventors

• Loesch Benedikt
• Noethlings Rolf

Classifications

• G01S13/343 Primary

  using sawtooth modulation · CPC title

• G01S13/348

  using square or rectangular modulation, e.g. diplex radar for ranging over short distances · CPC title

• G01S7/35

  Details of non-pulse systems · CPC title

• G01S13/346

  using noise modulation · CPC title

• G01S7/4039

  of sensor or antenna obstruction, e.g. dirt- or ice-coating · CPC title