IRCI Free MIMO OFDM SAR Using Circularly Shifted Zadoff-Chu Sequences

摘要

Cyclic prefix (CP) based MIMO-OFDM radar has been recently proposed fordistributed transmit antennas, where there is no inter-range-cell interference(IRCI). It can collect full spatial diversity and each transmitter transmitssignals with the same frequency band, i.e., the range resolution is notreduced. However, it needs to transmit multiple OFDM pulses consecutively toobtain range profiles for a single swath, which may be too long in time for areasonable swath width. In this letter, we propose a CP based MIMO-OFDMsynthetic aperture radar (SAR) system, where each transmitter transmits only asingle OFDM pulse to obtain range profiles for a swath and has the samefrequency band, thus the range resolution is not reduced. It is IRCI free andcan collect the full spatial diversity if the transmit antennas aredistributed. Our main idea is to use circularly shifted Zadoff-Chu sequences asthe weighting coefficients in the OFDM pulses for different transmit antennasand apply spatial filters with multiple receive antennas to divide the wholeswath into multiple subswaths, and then each subswath is reconstructed/imagedusing our proposed IRCI free range reconstruction method.