FMCW Radar Rx Channel Imbalance Estimation via Multiple Targets in the Same R-D Bin

In an automotive radar sensor, channel imbalance monitoring is an important task due to its effects on the estimation and detection performance of the radar. In this paper, we propose a method to estimate the gain and phase imbalances of the receive channels of a radar transceiver. This method is based on least squares estimation and uses object reflections in the radar scenery. However, it does not require knowledge of the locations of objects, which makes it a promising technique for online channel imbalance estimation. Furthermore, it permits the use of multiple objects that fall in the same range-Doppler bin, which speeds up the estimation process and makes it less scenario-dependent, compared to using only single objects. The obtained gain and phase imbalances are then applied to two applications: Rx channel calibration and solder ball break detection. Simulation and measurement results confirm the excellent performance of the proposed method.