Phase-Discontinuity Correction Method With an Overlapped Signal Structure in Stepped-Carrier OFDM Radar With Dual Transmitters

A phase-discontinuity correction method for a stepped-carrier orthogonal frequency-division multiplexing (SC-OFDM) radar is proposed. Correction is accomplished using an overlapped signal structure in both the time and frequency domains, made possible by implementing a radar system with dual transmitters (DTs). The overlap in the frequency domain is used to correct phase discontinuities in the frequency steps, and the overlap in the time domain allows lowering the effective measurement time loss due to guard intervals. The subband phase discontinuity of DTs is extracted by cross-correlating a received subsymbol with the frequency-overlapped subsymbol from the next frequency step. After the gain and phase values at the maximum correlation output are obtained, subband and subsymbol correction processes are applied alternately for each frequency step in a chained manner. Simulated range-Doppler maps are presented without and with phase-discontinuity corrections using the proposed signal structure. Also, an SC-OFDM radar system with DTs is implemented to prove the concept. The results show that phase discontinuities among the frequency steps in a block can be readily corrected using the proposed signal structure and correction method without precalibration using a reference target.