Interference mitigation in automotive radar systems by artificial doppler modulation

Patent metadata

Field	Value
Publication number	US-10908253-B2
Application number	US-201816604093-A
Country	US
Kind code	B2
Filing date	Mar 29, 2018
Priority date	Apr 12, 2017
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

A method of operating an automotive radar system that includes a radar transmitter unit for transmitting radar waveforms towards a scene, a radar receiving unit for receiving radar waveforms that have been reflected by a target in the scene, and an evaluation and control unit for decoding range-Doppler information from the received waveforms. The method includes: transmitting a first sequence of radar waveforms (x Tx ) and a second sequence of radar waveforms ({tilde over (x)} Tx,k ) towards the scene that differs from the first transmitted sequence of radar waveforms (x Tx ) by predetermined phase shifts (φ k ) such that each radar waveform ({tilde over (x)} Tx,k ) of the second sequence has a different predetermined phase shift (φ k ). First range-Doppler information and second range-Doppler information are decoded. Deviations of the second range-Doppler information from the first range-Doppler information are compared to at least one predetermined deviation value. Based on the results of the comparing, a potential interference condition is identified.

First claim

The invention claimed is:

1. A method of operating an automotive radar system for avoiding interference by other radar systems, the automotive radar system including:
a radar transmitter that is configured to transmit radar waveforms (x Tx , {tilde over (x)} Tx ) having a radar carrier frequency towards a scene,
a radar receiver that is configured for receiving radar waveforms (x Rx , {tilde over (x)} Rx ) that have been transmitted by the radar transmitter and have been reflected by a target in the scene, and
an evaluation and control unit that is configured for decoding range-Doppler information from the radar waveforms (x Rx , {tilde over (x)} Rx ) received by the radar receiver,

the method comprising steps of:
transmitting a first sequence of radar waveforms (x Tx ) towards a scene,
receiving first radar waveforms (x Rx ) that have been reflected by a target hit by the transmitted first sequence of radar waveforms (x Tx ),
decoding first range-Doppler information from the received first radar waveforms (x Rx ),
transmitting at least a second sequence of radar waveforms ({tilde over (x)} Tx,k ) towards the scene that differs from the first transmitted sequence of radar waveforms (x Tx ) by predetermined phase shifts (φ k ) such that each radar waveform ({tilde over (x)} Tx,k ) of the second sequence has a different predetermined phase shift (φ k ),
receiving second radar waveforms ({tilde over (x)} Rx,k ) that have been reflected by the target hit by the transmitted second sequence of radar waveforms ({tilde over (x)} Tx,k ),
decoding second range-Doppler information from the received second radar waveforms ({tilde over (x)} Rx,k ),
comparing deviations of the second range-Doppler information from the first range-Doppler information to at least one predetermined deviation value, and
based on the results of the comparing, identifying a potential interference condition.

2. The method as claimed in claim 1 , wherein the predetermined phase shifts (φ k ) are based on a Doppler frequency (f v ) derived from a predetermined velocity (v) relative to a target and the radar carrier frequency.

3. The method as claimed in claim 2 , wherein the predetermined velocity (v) is randomly selected from a predetermined range of velocities.

4. The method as claimed in claim 1 , wherein the steps of transmitting a sequence of radar waveforms include transmitting a plurality of consecutive radar waveforms (x Tx , {tilde over (x)} Tx,k ) of identical duration (τ).

5. The method as claimed in claim 1 , wherein the steps of decoding the first range-Doppler information and the second range-Doppler information comprises sorting the respective range-Doppler information into a plurality of range gates and a plurality of Doppler bins, and the step of comparing deviations comprises comparing a mutual shift between the range-Doppler information along the respective plurality of Doppler bins.

6. The method as claimed in claim 1 , wherein the steps of decoding include dechirping the received radar waveforms (x Rx , {tilde over (x)} Rx,k ) and carrying out either a fast Fourier transform or a correlation analysis at the dechirped radar waveforms.

7. The method as claimed in claim 1 , wherein the steps of transmitting sequences of radar waveforms (x Tx , {tilde over (x)} Tx,k ) towards the scene comprises transmitting frequency-modulated or phase-modulated continuous radar waves towards the scene.

8. An automotive radar system, comprising:
a radar transmitter that is configured to transmit at least a sequence of radar waveforms (x Tx ) towards a scene according to a first predetermined pattern, the radar waveforms having a radar carrier frequency,
a radar receiver that is configured for receiving radar waveforms (x Rx ) that have been transmitted by the radar transmitter and have been reflected by a target in the scene,
an evaluation and control unit that is configured for decoding range-Doppler information from the radar waveforms (x Rx ) received by the radar receiver,

wherein:
the radar transmitter is further configured to transmit, at predetermined points in time and/or in predetermined time intervals, a sequence of radar waveforms ({tilde over (x)} Tx ) according to a second predetermined pattern that differs from the first predetermined pattern by predetermined phase shifts (φ k ) such that each radar waveform ({tilde over (x)} Tx,k ) of the second sequence has a different predetermined phase shift (φ k ),

and wherein:
the evaluation and control unit is configured to:
decode first range-Doppler information from radar waveforms (x Rx ) received after reflection of the sequence of radar waveforms (x Tx ) according to the first predetermined pattern at the target,
decode second range-Doppler information from radar waveforms ({tilde over (x)} Rx,k ) received after reflection of the sequence of radar waveforms ({tilde over (x)} Tx,k ) according to the second predetermined pattern at the target,
compare deviations of the first range-Doppler information from the second range-Doppler information to at least one predetermined deviation value, and
identify, based on the result of the comparison, a potential interference condition.

9. The automotive radar system as claimed in claim 8 , further comprising pluralities of range gates and pluralities of Doppler bins for sorting the decoded first range-Doppler information and the decoded second range-Doppler information, wherein deviations of the first range-Doppler information from the second range-Doppler information are indicated by mutual shifting of activated positions along the pluralities of Doppler bins.

10. The automotive radar system as claimed in claim 8 , wherein the radar transmitter and the radar receiver form an integral part of a transceiver.

11. The automotive radar system as claimed in claim 8 , wherein the evaluation and control unit comprises a processor and a digital data memory to which the processor has data access.

12. A non-transitory computer-readable medium for controlling automatic execution of the method as claimed in claim 1 , wherein each of the transmitting, receiving, decoding, and comparing steps to be conducted are stored on the computer-readable medium as a program code, wherein the computer-readable medium comprises a part of the automotive radar system or a separate controller and is executable by a processor of the automotive radar system or the separate controller.

Assignees

• Iee Sa

Inventors

• Beise Hans-Peter
• Schroder Udo
• Stifter Thomas

Classifications

• G01S7/023 Primary

  Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques (auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36) · CPC title

• G01S7/356

  involving particularities of FFT processing · CPC title

• G01S13/931

  of land vehicles · CPC title

• G01S7/34

  Gain of receiver varied automatically during pulse-recurrence period, e.g. anti-clutter gain control · CPC title

• G01S7/354

  Extracting wanted echo-signals (Doppler systems G01S13/50) · CPC title