Atomic Norm-Based Joint Delay-Doppler Shift Estimation for OFDM Passive Radar

In this letter, we consider the problem of joint delay-Doppler shift estimation of multiple moving targets in a passive radar system using orthogonal frequency-division multiplexing communication signals. An atomic norm-based algorithm is proposed for better estimation performance and higher robustness against the demodulation error. We utilize a new atomic set with the unknown demodulation error from the direct-path signal included, aiming to reduce the impact of high symbol error rate (SER), in contrast to previous works that introduce l(1)-norm to exploit the sparsity of the afore-mentioned error. By converting to a semidefinite program, the problem is solved under the convex optimization framework. Simulation results show that the proposed method performs better under high SER conditions.