Detection of interference-induced perturbations in FMCW radar systems

Patent metadata

Field	Value
Publication number	US-11428775-B2
Application number	US-202017019828-A
Country	US
Kind code	B2
Filing date	Sep 14, 2020
Priority date	Sep 16, 2019
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A radar system includes a local oscillator for generating a local oscillator signal, transmission channels, and a reception channel. The transmission channels are designed to generate and output RF radar signals based on the local oscillator signal The transmission channels have phase shifters for setting the phase of the RF radar signals. The reception channel is designed to receive an RF signal and to convert it into a baseband signal by using the local oscillator signal supplied thereto. A method includes operating the local oscillator in a CW mode, setting a specific combination of phase shifts for the phase shifters of the transmission channels, altering the phase of the local oscillator signal supplied to the reception channel or of the phase shifts of the phase shifters by a phase offset, and ascertaining that phase offset for which the baseband signal at least approximately assumes a maximum.

First claim

What is claimed is:

1. A method for a radar system comprising a local oscillator (LO) for generating a local oscillator signal; an LO phase shifter configured to receive the LO signal and apply a phase shift to the LO signal according to a phase setting to generate a phase-shifted LO signal; a plurality of transmission channels that are each supplied with the LO signal; a reception channel that is supplied with the phase-shifted LO signal wherein each of the plurality of transmission channels is configured generate and output a respective RF radar signal based on the LO signal; a plurality of phase shifters, each transmission channel including a different one of the plurality of phase shifters and each phase shifter being configured to alter a phase of a respective RF radar signal of its transmission channel, and wherein the reception channel is configured to receive an RF signal and to convert it into a baseband signal by using the phase-shifted local oscillator signal supplied to the reception channel, wherein the method comprises:
operating the local oscillator in a continuous wave (CW) mode;
setting a specific combination of phase shifts for the plurality of phase shifters of the plurality of transmission channels;
while the specific combination of phase shifts remains fixed, altering the phase setting of the LO phase shifter to generate the phase-shifted LO signal having a plurality of LO phase shifts;
measuring a signal amplitude of the DC signal component of the baseband signal for each of the plurality of LO phase shifts; and
determining for which LO phase shift out of the plurality of LO phase shifts the signal amplitude of the DC signal component assumes a maximum value.

2. The method as claimed in claim 1 ,
wherein determining for which LO phase shift out of the plurality of LO phase shifts the signal amplitude of the DC signal component assumes a maximum value is performed for a plurality of specific combinations of phase shifts of the plurality of phase shifters of the plurality of transmission channels.

3. The method as claimed in claim 2 , further comprising:
storing the phase setting for determined LO phase shift for each of the plurality of specific combinations of phase shifts.

4. The method as claimed in claim 3 , further comprising:
operating the local oscillator in a frequency-modulated continuous-wave (FMCW) mode;
modulating the phase of the output RF radar signals, wherein a prescribable modulation scheme is used to set different specific combinations of phase shifts for the plurality of phase shifters of the plurality of transmission channels sequentially, and
wherein the previously ascertained and stored phase offset setting is also used for each specific combination of phase shifts that is set.

5. The method as claimed in claim 1 , further comprising:
applying the phase setting corresponding to the determined LO phase shift to the LO phase shifter for the specific combination of phase shifts to compensate for a phase offset in the baseband signal.

6. The method as claimed in claim 1 ,
wherein the received RF signal comprises a signal component that is caused by crosstalk by the RF radar signals.

7. The method as claimed in claim 1 ,
wherein the altering of the LO phase shifts of the LO phase shifter does not alter the phase differences between the RF radar signals.

8. A radar system, comprising:
a local oscillator (LO) for generating an LO signal;
an LO phase shifter configured to receive the LO signal and apply a phase shift to the LO signal according to a phase setting to generate a phase-shifted LO signal;
a plurality of transmission channels that are each supplied with the LO signal;
a reception channel that is supplied with the phase-shifted LO signal,
wherein each of the plurality of transmission channels is configured generate and output a respective RF radar signal based on the LO signal, and
wherein the reception channel is configured to receive an RF signal and to convert it into a baseband signal by using the phase-shifted LO signal supplied to the reception channel;
a plurality of phase shifters, each transmission channel including a different one of the plurality of phase shifters and each phase shifter being configured to alter a phase of a respective RF radar signal of its transmission channel; and
a controller that is configured to:
configure the local oscillator for a continuous wave (CW) mode;
set a specific combination of phase shifts for the plurality of phase shifters of the plurality of transmission channels;
while the specific combination of phase shifts remains fixed, alter the phase setting of the LO phase shifter to generate the phase-shifted LO signal having a plurality of LO phase shifts; and

at least one processor configured to measure a signal amplitude of the DC signal component of the baseband signal for each of the plurality of LO phase shifts and determine for which LO phase shift out of the plurality of LO phase shifts the signal amplitude of the DC signal component assumes a maximum value.

9. The radar system as claimed in claim 8 , wherein the system controller is further configured to ascertain the LO phase shift for which the signal amplitude of the DC signal component of the baseband signal assumes a maximum value, and to store the ascertained LO phase shift, for each of a plurality of specific combinations of phase shifts of the plurality of phase shifters.

10. The radar system as claimed in claim 8 , wherein the controller is configured to select the phase setting corresponding to the LO phase shift that causes the signal amplitude of the DC signal component of the baseband signal to assume a maximum value as an optimum phase setting for the specific combination of phase shifts.

11. The radar system as claimed in claim 8 , wherein:
the controller is configured to rotate the LO phase shift of the phase-shifted local oscillator signal in steps through a 360° phase rotation, and
the at least one processor configured determine for which LO phase shift through the 360° phase rotation causes the signal amplitude of the DC signal component of the baseband signal to assume a maximum value.

12. The radar system as claimed in claim 8 , wherein the RF signal comprises a leakage signal or a crosstalk signal that is a superimposition of each of the RF radar signals transmitted by the plurality of transmission channels.

13. The radar system as claimed in claim 8 , wherein the signal amplitude of the DC signal component of the baseband signal is a DC value.

14. A method, comprising:
setting a first relative phase and a second relative phase in a radar system, wherein the first relative phase determines a first phase difference between a local oscillator (LO) signal used by a reception channel of the radar system and a first RF radar signal output by a first transmission channel of the radar system and wherein the second relative phase determines a second phase difference between the LO signal used by the reception channel of the radar system and a second RF radar signal output by a second transmission channel of the radar system;
wherein the setting of the first relative phase and the second relative phase comprises:
selecting a first phase shift and a second phase shift of a first phase configuration of a modulation scheme for the first transmission channel and the second transmission channel, respectively;
ascertaining a first phase offset associated with the first phase configuration of the modulation scheme wherein ascertaining a first phase offset comprises:
applying, by a LO phase shifter, a phase shift to the LO signal according to a phase

Assignees

• Infineon Technologies Ag

Inventors

• Melzer Alexander
• Dollinger Andreas
• Kobler Rene
• Krebelder Georg
• Wagner Christoph
• Wiessflecker Martin

Classifications

• G01S7/352

  Receivers · CPC title

• 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

• G01S7/03

  Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver · CPC title

• G01S7/354

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

• G01S13/931

  of land vehicles · CPC title