Adaptive transmission and interference cancellation for MIMO radar

Patent metadata

Field	Value
Publication number	US-9945943-B2
Application number	US-201715632754-A
Country	US
Kind code	B2
Filing date	Jun 26, 2017
Priority date	Apr 7, 2016
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

A radar system has different modes of operation. In one mode the radar operates as a single-input, multiple-output (SIMO) radar system utilizing one transmitted signal from one antenna at a time. Codes with known excellent autocorrelation properties are utilized in this mode. At each receiver the response after correlating with various possible transmitted signals is measured in order to estimate the interference that each transmitter will represent at each receiver. The estimated effect of the interference from one transmitter on a receiver that correlates with a different code is used to mitigate the interference. In another mode, the radar operates as a MIMO radar system utilizing all the antennas at a time. Interference cancellation of the non-ideal cross correlation sidelobes when transmitting in the MIMO mode are employed to remove ghost targets due to unwanted sidelobes.

First claim

The invention claimed is:

1. A method for mitigating self-interference in a radar system for a vehicle, the method comprising:
providing a radar system comprising (i) a plurality of transmitters configured for installation and use on a vehicle and configured to transmit radio signals, and (ii) a plurality of receivers configured for installation and use on the vehicle and configured to receive radio signals that include the transmitted radio signals reflected from objects in the environment;
transmitting radio signals with only a first transmitter of the plurality of transmitters and receiving radio signals transmitted from the first transmitter with at least one receiver of the plurality of receivers;
correlating the received radio signals with each receiver of the at least one receiver to estimate interference that the first transmitter will represent at each receiver of the at least one receiver; and
mitigating at each receiver of the at least one receiver the estimated interference that is due to interfering radio signals transmitted by the first transmitter.

2. The method of claim 1 further comprising:
transmitting radio signals with only a second transmitter of the plurality of transmitters and receiving radio signals transmitted from the second transmitter with the at least one receiver of the plurality of receivers;
correlating the received radio signals with each receiver of the at least one receiver to estimate interference that the second transmitter will represent at each receiver of the at least one receiver; and
mitigating at each receiver of the at least one receiver the estimated interference that is due to interfering radio signals transmitted by the first and second transmitters.

3. The method of claim 2 , wherein transmitting with a first transmitter comprises the first transmitter transmitting with a single antenna.

4. The method of claim 3 , wherein transmitting with a second transmitter comprises the second transmitter transmitting with a single antenna that is different from the single antenna used by the first transmitter.

5. The method of claim 1 , wherein each transmitter of the plurality of transmitters is configured to phase modulate the transmitted radio signals using a unique spreading code.

6. The method of claim 5 , wherein transmitting with only a first transmitter comprises further modulating the transmitted radio signals with spreading codes selected with known autocorrelation properties.

7. The method of claim 6 , wherein the estimated effect of the interference from a particular transmitter on a particular receiver that correlates with a different set of spreading codes is used to mitigate the interference from the particular transmitter at the particular receiver.

8. The method of claim 6 , wherein a length of the spreading codes is selected based upon an interference level.

9. The method of claim 6 , wherein the spreading codes are binary codes, and comprise one of m-sequences, APAS sequences, Golay sequences, Frank-Zadoff-Chu sequences, and Hadamard codes.

10. The method of claim 1 , wherein transmitting radio signals with only a first transmitter of the plurality of transmitters comprises transmitting for a first period of time, and wherein transmitting radio signals with only a second transmitter of the plurality of transmitters comprises transmitting for a second period of time.

11. The method of claim 1 , wherein radio signals transmitted from only the first transmitter are received with each receiver of the plurality of receivers.

12. A radar sensing system for a vehicle, the radar sensing system comprising:
a transmit pipeline configured for installation and use on a vehicle, wherein the transmit pipeline comprises a plurality of transmitters configured to transmit radio signals;
a receive pipeline configured for installation and use on the vehicle, wherein the receive pipeline comprises a plurality of receivers configured to receive radio signals that include the transmitted radio signals reflected from objects in the environment;
a controller configured to direct during a first operational mode only a first transmitter of the plurality of transmitters to transmit, wherein radio signals transmitted from only the first transmitter are received by at least one receiver of the plurality of receivers;
wherein, during the first operational mode, each receiver of the at least one receiver is configured to correlate the received radio signals to estimate interference that the first transmitter will represent at each receiver of the at least one receiver; and
wherein, during a second operational mode, each receiver of the at least one receiver is configured to mitigate the estimated interference that is due to the interfering radio signals transmitted by the first transmitter.

13. The radar sensing system of claim 12 , wherein during the first operational mode, the controller is configured to select which receivers of the plurality of receivers receive the transmitted radio signals.

14. The radar sensing system of claim 12 , wherein during the first operational mode, the controller is configured to direct only a second transmitter of the plurality of transmitters to transmit, and wherein radio signals transmitted from only the second transmitter are received by the at least one receiver of the plurality of receivers, and wherein, during the first operational mode, each receiver of the at least one receiver is configured to correlate the received radio signals to estimate interference that the second transmitter will represent at each receiver of the at least one receiver, and wherein, during the second operational mode, each receiver of the at least one receiver is configured to mitigate the estimated interference that is due to the interfering radio signals transmitted by the first and second transmitters.

15. The radar sensing system of claim 14 , wherein, during the first operational mode, the first transmitter transmits with a single antenna.

16. The radar sensing system of claim 15 , wherein, during the first operational mode, the second transmitter transmits with a different single antenna.

17. The radar sensing system of claim 12 , wherein each transmitter of the plurality of transmitters is configured to phase modulate the transmitted radio signals using a unique spreading code.

18. The radar sensing system of claim 17 , wherein the plurality of transmitters are configured to modulate the transmitted radio signals with spreading codes selected with known autocorrelation properties.

19. The radar sensing system of claim 18 , wherein the estimated effect of the interference from a particular transmitter on a particular receiver that correlates with a different set of spreading codes is used to mitigate the interference from the particular transmitter at the particular receiver.

20. The radar sensing system of claim 19 , wherein a length of the spreading codes is selected based upon an interference level, and wherein the spreading codes are binary codes, and comprise one of m-sequences, APAS sequences, Golay sequences, Frank-Zadoff-Chu sequences, and Hadamard codes.

21. The radar sensing system of claim 12 , wherein transmitting radio signals with only a first transmitter of the plurality of transmitters comprises transmitting for a first period of time, and wherein transmitting radio signals with only a second transmitter of the plurality of transmitters comprises transmitting for a second period of time.

22. The radar sensing syste

Assignees

• Uhnder Inc

Inventors

• Stark Wayne E
• Bordes Jean P
• Davis Curtis
• Rao Raghunath K
• Maher Monier
• Hegde Manju
• Schmid Otto A

Classifications

• G01S2013/93271

  in the front of the vehicles · CPC title

• G01S13/87

  Combinations of radar systems, e.g. primary radar and secondary radar · CPC title

• G01S2013/9322

  using additional data, e.g. driver condition, road state or weather data · CPC title

• H04B7/0413

  MIMO systems · CPC title

• H04L27/2278

  using correlation techniques, e.g. for spread spectrum signals · CPC title