PMCW-PMCW interference mitigation

A radar sensing system for a vehicle, the radar sensing system comprising:

• at least one transmitter configured for installation and use on a vehicle, and operable to transmit a phase modulated radio signal using a different spreading code for each transmitter of the at least one transmitter;
• at least one receiver configured for installation and use on the vehicle, and operable to receive a radio signal, wherein the radio signal includes the transmitted radio signal reflected from an object, and wherein each receiver of the at least one receiver correlates the received radio signal with a spreading code that matches the spreading code used by a corresponding transmitter of the at least one transmitter;
• wherein the at least one receiver is further operable to receive an interfering radio signal transmitted by a transmitter of another radar sensing system, and wherein the interfering radio signal interferes with the reflected radio signal;
• wherein a processor, responsive to the spreading codes used by both radars having a same period, adjusts at least one of the at least one transmitter and the at least one receiver to limit interference from the other radar sensing system;
• and
• wherein the at least one receiver is further operable to correlate the received radio signal with a spreading code that is different from any spreading code that is used by the at least one transmitter, such that the at least one receiver determines correlation values for the interfering radio signal without the reflected radio signal, and wherein the correlation values are measured by the processor to determine the interferences levels.

A method for mitigating interference in a radar sensing system comprising at least one transmitter configured for installation and use on a vehicle and at least one receiver configured for installation and use on the vehicle, the method comprising:

• transmitting with the at least one transmitter a radio signal;
• receiving with the at least one receiver a radio signal, wherein the received radio signal includes the transmitted radio signal reflected from an object;
• receiving with the at least one receiver an interfering radio signal transmitted by a transmitter of another radar sensing system, wherein the interfering radio signal interferes with the reflected radio signal;
• causing the at least one transmitter to selectively transmit radio signals;
• selecting spreading codes that reduce interference based on measuring interference levels with different spreading codes;
• phase modulating the radio signal for transmission according to a spreading code;
• correlating with the at least one receiver the received radio signal using the same spreading code as used by the at least one transmitter;
• and
• correlating with the at least one receiver the received radio signal with a spreading code that is different from any spreading code that is used by the at least one transmitter, such that the at least one receiver determines correlation values for the interfering radio signal, and wherein the correlation values are measured to determine the interference levels.