Abstract
In the missile borne monopulse radar system, effectiveness of jamming the receiver in presence of internal and external noise is much significant. In this paper, jamming of such radar receiver in frequency domain is studied when White Gaussian Noise (WGN) and Phase Noise (PN) signals are injected into the receiver in two separate cases. The missile radar receiver operates on unmodulated continuous wave sinusoidal echo signal and the jammer is assumed to be a WGN source which generates Gaussian noise samples with zero mean. The Gaussian noise signal is injected into the receiver along with the radar echo signal and the noise power required for breaking the frequency lock in the receiver is reported. Initially, it is assumed that receiver is locked onto the desired radar echo signal frequency as the noise power is too less to break the frequency lock of the receiver. It is verified that Gaussian noise power required for jamming the receiver depends upon how the power is interpreted. For our simulation, the noise power is interpreted in symbol rate bandwidth, sampling frequency bandwidth, and in single-sided and double-sided power spectral density. The break-lock in the radar receiver is presented. In the case of phase noise, the noise is added to phase of the radar echo signal and the phase noise mask required for break-lock in the receiver is studied. The phase noise is specified through a phase noise mask consisting of frequency and dBc/Hz values. It is verified that phase noise mask required for jamming the receiver is less when frequency offset from echo signal is large. The effects of windowing techniques when implemented in the phase noise measurement are presented. It is shown that the windowing technique reduces the phase noise required for breaking the frequency lock in the receiver. The effectiveness of noise jamming is carried out through computer simulation using AWR (Visual System Simulator) software. The receiver response is observed online in the frequency spectrum of the signal.