Real-Time Cognitive Sense-and-Notch Radar

Spectrum sensing and transmit waveform frequency notching is a form of cognitive radar that seeks to reduce mutual interference with other spectrum users in a cohabitated band. With the reality of increasing radio frequency (RF) spectral congestion, radar systems capable of dynamic spectrum sharing are needed. The cognitive sense-and-notch (SAN) emission strategy is experimentally demonstrated as an effective way to reduce the interference that the spectrum sharing radar causes to other in-band users. The physical radar emission is based on a random FM waveform structure possessing attributes that are inherently robust to range-Doppler sidelobes. To contend with dynamic interference the transmit notch may be required to move during the coherent processing interval (CPI), which introduces a nonstationarity effect that results in increased residual clutter after cancellation. The nonstationarity effect is characterized and compensated for using computationally efficient processing methods. The steps from initial analysis of cognitive system performance to implementation of sense-and-notch radar spectrum sharing in real-time are discussed.