Amplifier-in-the-Loop Adaptive Radar Waveform Synthesis

Adaptive algorithms having the capacity to perform real-time optimization in response to a dynamic environment will be necessary for the development of a cognitive radar technology. This paper details an amplifier-in-the-loop algorithm to synthesize radar waveforms which are optimized for desired ambiguity function characteristics in a monostatic radar system, with constraints on the peak-to-average power ratio and spectrum of the waveform. The algorithm uses alternating projections to search for a waveform whose ambiguity function best approximates the goal for a volume-based constraint in desired regions of the range-Doppler plane. Results are shown for both simulation and measurement cases, both with and without the effects of a nonlinear amplifier. This waveform synthesis method is expected to be useful in real-time adaptive radar systems.