Optimal Frequency Hopping Patterns With Ideal Autocorrelation and Cross Correlation for MIMO-SAR Signal Design

This paper presents an orthogonal waveform design framework for multiple-input multiple-output synthetic aperture radar (MIMO-SAR) systems using optimal frequency hopping patterns (OFHPs) derived from two-dimensional cyclic shifts of an algebraically constructed Costas array. The resulting waveform set exhibits ideal two-dimensional autocorrelation and cross-correlation properties, enabling enhanced resolution and reduced inter-antenna interference. An ambiguity volume reduction strategy based upon the proposed OFHPs is introduced to improve performance in cluttered environments with overlapping reflections. Moreover, each frequency-hopping subpulse incorporates a subchirp to enhance resolution, while alternating positive and negative-slope subchirps are employed to suppress sidelobes in the ambiguity and cross-ambiguity functions. Analytical expressions are established to characterize the signal synthesis process and to elucidate the associated correlation properties of the proposed OFHP-based waveform design. Simulation results and comparative analysis with existing mainstream MIMO-SAR waveforms demonstrate the effectiveness of the proposed method for high-resolution imaging, robust interference suppression, and advanced MIMO-SAR applications, as evidenced by superior ambiguity and cross-ambiguity performance, reduced ambiguity volume, and mitigated mutual interference.