Close-Range Direction of Arrival Estimation in the Presence of Clock Jitter

Many forms of small-size radars suffer from minor clock oscillations due to crystalline impurities in their internal clocks, causing time-varying clock offsets between the transmitter and the receivers. This offset causes a bias and an increased variance in the positioning of close-range targets, limiting the achievable accuracy well beyond the expected estimation limitations. This performance is further limited by the commonly used approximative model ignoring the curvature of the impinging wavefront. This is done to allow for computationally efficient estimators, but notably reduces the performance for close-range reflectors. In this paper, we introduce a computationally efficient and robust direction of arrival estimator that partly allows for these model mismatches, significantly improving the estimation performance for close-range reflectors as compared to traditional estimators.