Generation of Multiple-Input Multiple-Output Radar Waveforms

Helios Remote Sensing Systems, Inc. proposes to identify and develop techniques to produce a high number of orthogonal waveforms with optimal rejection for use in waveform diverse MIMO Over-The-Horizon radar applications. We will investigate issues pertaining to simultaneously generating and coherently processing a large number of transmitted and received waveforms each of 25 kHz bandwidth and all at a carrier frequency of 5 MHz. Issues to be considered include ambiguity function and cross ambiguity function performance including autocorrelation sidelobe levels and waveform cross correlation, matched filters’ signal rejection properties, mutual coherent interference, atmospheric and phenomenological degradation impact, and output signal-to-interference-plus-noise ratio. Advanced orthogonal waveforms and adaptive mutual coherent interference rejection, compatible with CW and pulsed MIMO OTH radar architectures, will be researched, designed and validated using computer simulations. Of particular interest are telecommunications waveforms, nested Costas codes and noise-like waveforms which possess spatial, temporal, and frequency diversity. Also, we believe that severe mutual coherent interference and phenomenological degradation effects (atmospheric, multipath, etc.) could significantly degrade performance of “fragile” orthogonal waveforms. Therefore, an integral part of the proposed waveform architecture design is adaptive mutual coherent interference rejection processing to mitigate these degrading effects.