| CPC G01S 7/4026 (2013.01) [G01S 7/40 (2013.01); G01S 7/403 (2021.05); G01S 7/4034 (2021.05); G01S 13/003 (2013.01)] | 15 Claims |
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1. A method of calibrating a radar system, comprising:
obtaining first radar return data from a multiple-input and multiple-output (MIMO) antenna array, wherein:
the first radar return data comprises one or more samples of a radio wave signal impinging on a MIMO receiver array of the MIMO antenna array, wherein each of the one or more samples of the radio wave signal comprises one or more sub-samples of a radio wave signal impinging on respective receiver antennas of a plurality of receiver antennas of the MIMO receiver array; and
the radio wave signal impinging on the MIMO receiver array comprises a combination of radar signal echoes of one or more radar signals reflected by one or more calibration reflectors, wherein each of the radar signal echoes impinge on the MIMO receiver array at a pair comprising a respective azimuth angle and a respective elevation angle; and
each of the one or more radar signals is generated by a MIMO transmitter array of the MIMO antenna array, wherein each of the one or more radar signals comprises one or more mutually orthogonal radar sub-signals generated by one or more transmitter antennas of the MIMO transmitter array;
processing the first radar return data to determine, for each respective pair of azimuth angle and elevation angle of the radar signal echoes, a calibration vector, wherein the calibration vector comprises a calibration factor for each of the plurality of receiver antennas; and
processing received radar signals according to the determined calibration vectors by:
generating a frequency steering matrix for the MIMO antenna array, wherein the frequency steering matrix comprises, for each of a plurality of pairs of azimuth angles and elevation angles within a range of pairs of azimuth angles and elevation angles, a product of a frequency steering vector associated with the respective pair of azimuth angle and elevation angle and the calibration vector associated with the respective pair of azimuth angle and elevation angle;
generating a current covariance matrix of the first radar return data that is initialized to an identity matrix; and
iteratively calculating, until a stopping condition is met, a current power spectrum vector of the first radar return data by:
calculating a new power spectrum vector using the frequency steering matrix and the current covariance matrix;
calculating a new covariance matrix using the frequency steering matrix and the new power spectrum vector; and
updating the current power spectrum vector to the new power spectrum vector and updating the current covariance matrix to the new covariance matrix.
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