Coherence of Active Noise Interference in Radar Systems with Antenna Arrays

We analyze the coherence degree of active noise interference in radar systems. The entropy of the distribution of eigenvalues of the interference correlation matrix is used as a quantitative measure of the coherence degree of interference. The main factors influencing the coherence of active noise interference are analyzed, namely, the interference spectrum width and the interferenceenvironment nonstationarity due to variation in the angular relations between the antenna-array beam and the interference source in the process of the radar observation. It is shown that the analysis of coherence of an active noise interference allows one to quantitatively estimate the notions of wideband and narrowband interference.