Direction finding in MIMO radar with unknown transmitter and/or receiver gains and phases

This paper addresses the problem of direction finding in multiple-input multiple-output radars with unknown transmitter and/or receiver gains and phases. Three different cases are considered and the corresponding methods for determining the direction-of-arrivals (DOAs) of multiple targets are presented. In the first case, the transmitter is well calibrated, but the receiver is uncalibrated with unknown gains and phases. On the contrary, the second case assumes that the receiver is well calibrated, whereas the transmitter is not. In the third case, the transmitter is uncalibrated, and the receiver is partly calibrated, i.e. only a portion of the receiver array is well calibrated and the remaining sensor elements have gain and phase uncertainties. For the first two cases, it is shown that a type of determinant-based or eigenvalue-based spectral can be utilized to determine the DOAs. For the third one, an ESPRIT-like algorithm is developed. Numerical examples are provided to validate the proposed methods and the results show that these methods are insensitive to the unknown gains and phases.