A radar countermeasures receiver

In many radar countermeasure applications it is necessary to estimate the angle of arrival (AOA), frequency and the pulse repetition frequency (PRF) of each radar emitter in a dense signal environment. The parameters of multiple simultaneous emitters are estimated using a fast fourier transform (FFT) on sampled data collected from three data channels. Current methods of frequency estimation and AOA computation are based on well established instantaneous frequency discriminators and interferometer receivers, respectively. However, significant sensitivity and resolution enhancements are achieved with the application of digital signal processing. The receiver described can estimate either the frequency or the AOA of radar emitters with respect to their PRFs using information embedded in the cross-correlation of signals obtained from three data channels that are delayed replicas of each other