High resolution automotive radar system with forward and backward difference co-array processing

A distributed aperture radar system comprising first and second small aperture radar devices that are physically distributed from one another and connected to a radar control processing unit,

• the first small aperture radar device comprising a first plurality of transmit and receive antennas coupled to a first signal processor component that is configured to generate at least a first mono-static virtual array aperture and a first bi-static virtual array aperture in response to a first radar signal transmitted, respectively, from the first small aperture radar device or the second small aperture radar device;
• the second small aperture radar device comprising a second plurality of transmit and receive antennas coupled to a second signal processor component that is configured to generate at least a second mono-static virtual array aperture and a second bi-static virtual array aperture in response to a second radar signal transmitted, respectively, from the second small aperture radar device or the first small aperture radar device;
• and
• the radar control processing unit configured:
• to coherently combine virtual array apertures from the first and second distributed radar devices to construct an extended bi-static MIMO virtual array aperture that is larger than the first or second bi-static MIMO virtual array apertures, and
• to construct a bi-static MIMO forward difference virtual array aperture by performing forward difference co-array processing on the extended bi-static MIMO virtual array aperture to fill in holes in the extended bi-static MIMO virtual array aperture, thereby mitigating or suppressing spurious sidelobes caused by gaps or holes in the extended bi-static MIMO virtual array aperture,
• where radar control processing unit is configured to generate the second bi-static virtual array aperture after selecting the first small aperture device to operate as a master unit and selecting the second small aperture radar device to operate as a slave unit by:
• processing target returns and an eavesdropped signal from the first small aperture radar device with fast and slow time processing steps,
• computing an estimated frequency offset and an estimated phase offset between the first and second small aperture radar devices based on information derived from the fast and slow time processing steps, and
• applying the estimated frequency offset and estimated phase offset to generate the second bi-static virtual array aperture at the second small aperture radar device that is coherent in frequency and phase with the mono-static virtual array aperture generated by the first small aperture radar device selected to operate as the master unit.