Residue cancellation for automated vehicle MIMO radar

1. A Pseudo-Random Phase Modulation (PRPM) multiple-input-multiple-output (MIMO) radar system suitable for use on an automated vehicle, said system comprising:

a first transmit-antenna that transmits a first transmit-signal generated by a first PRPM-code;

a second transmit-antenna that transmits a second transmit-signal generated by a second PRPM-code;

a receive-antenna used to detect a first reflected-signal arising from the first transmit-signal and a second reflected-signal arising from the second transmit-signal; and

a controller in communication with the receive-antenna and operable to generate the first PRPM-code and the second PRPM-code, said controller configured to

generate a first sub-channel-output based on a down-converted-signal from the receive-antenna and the first PRPM-code,

generate a second sub-channel-output based on the down-converted-signal from the receive-antenna and the second PRPM-code,

determine a first residue-signal based on the second sub-channel-output, and

determine a first residue-removed-signal by subtracting the first residue-signal from the first sub-channel-output.

2. The system in accordance with claim 1 , wherein the first residue-signal is determined based on a convolution of an output signal of a second frequency-domain-modulation with a frequency transformation of a cross-correlation of the first PRPM-code and the second PRPM-code.

3. The system in accordance with claim 1 , wherein the controller is further configured to

determine a second residue-signal based on the first sub-channel-output, and

determine a second residue-removed-signal based on subtracting the second residue-signal from the second sub-channel-output.

4. The system in accordance with claim 3 , wherein the second residue-signal is determined based on a convolution of an output signal of a first frequency-domain-modulation with a frequency transformation of a cross-correlation of the second PRPM-code and the first PRPM-code.

5. The system in accordance with claim 1 , wherein the first residue-signal is determined based on a first time-domain-modulation of an inverse-frequency-transform of an output signal of a second frequency-domain-modulation by the second PRPM-code and a complex conjugate of the first PRPM-code, and a first frequency transformation of the first time-domain-modulation.

6. The system in accordance with claim 1 , wherein the second residue-signal is determined based on a second time-domain-modulation of an inverse-frequency-transform of an output signal of a first frequency-domain-modulation by the first PRPM-code and a complex conjugate of the second PRPM-code, and a second frequency transformation of the second time-domain-modulation.

7. The system in accordance with claim 1 , wherein the controller is further configured to repeat multiple-iterations of steps to determine the first residue-removed-signal.

8. A method to operate a Pseudo-Random Phase Modulation (PRPM) multiple-input-multiple-output (MIMO) radar system suitable for use on an automated vehicle, said method comprising:

providing a first transmit-antenna that transmits a first transmit-signal generated by a first PRPM-code;

providing a second transmit-antenna that transmits a second transmit-signal generated by a second PRPM-code;

providing a receive-antenna used to detect a first reflected-signal arising from the first transmit-signal and a second reflected-signal arising from the second transmit-signal;

generating the first PRPM-code and the second PRPM-code;

generating a first sub-channel-output based on a down-converted-signal from the receive-antenna and the first PRPM-code;

generating a second sub-channel-output based on the down-converted-signal from the receive-antenna and the second PRPM-code;

determining a first residue-signal based on the second sub-channel-output; and

determining a first residue-removed-signal by subtracting the first residue-signal from the first sub-channel-output.