Effectiveness of External Noise Jamming in Missile Borne Monopulse Radar Receivers

Abstract

 Abstract—This paper describes the external noise jamming of monopulse radar receiver when White Gaussian Noise (WGN) and Phase Noise (PN) signals are injected into the receiver. Initially, it is assumed that the receiver is locked onto the desired radar echo signal frequency in the presence of external noise signal as the noise power is too less to break the frequency lock of the receiver. It is shown that the Gaussian noise power required for jamming the receiver depends upon how the power is interpreted. In this paper, the Gaussian noise power is interpreted in symbol rate bandwidth, sampling frequency bandwidth, in single-sided and double-sided power spectral density. In the case of phase noise jamming, the phase noise mask (dBc/Hz) required for break-lock in the receiver is studied. It is verified that phase noise power required for jamming the receiver is less when frequency offset from the radar echo signal is large. The simulation result shows that phase noise mask of -72 is required when the frequency offset from the echo signal is 10 MHz. The effectiveness of external noise jamming is carried out through computer simulation using AWR (Visual System Simulator) software. interference as in case of denial jamming. In principle, the optimal jamming signal has the characteristics of receiver noise; in practice this may be difficult to achieve (4). In this paper, noise jamming of missile borne monopulse radar receiver with external White Gaussian Noise (WGN) and Phase Noise (PN) signal is analyzed. For significant effectiveness of the noise jamming, WGN is chosen ideally because of maximum entropy, or uncertainty of any random waveform for a specific average power. For our simulation, a monopulse radar receiver with third order loop is designed with a typical loop bandwidth of 1 MHz. The receiver operates on unmodulated sinusoidal radar echo signal of 10 dbm power. The radar echo after down converted to an intermediate frequency of 30 MHz is injected into the receiver loop along with the WGN signal and the noise power required for break-lock in the receiver is reported. It is seen that the Gaussian noise power required for break-lock in the receiver depends upon how the power is interpreted. In this context, the noise power is interpreted in symbol rate bandwidth, sampling frequency bandwidth, and in single-sided and double-sided power spectral density which are discussed in detail in the subsequent section. In another case, phase noise is generated by passing WGN through an FIR filter. This is added to the phase of the radar echo signal to simulate the phase noise which is specified through phase noise mask consisting of frequency and dBc/Hz values and the phase noise mask required for break-lock in the receiver is presented. It is seen that phase noise power required for break-lock depends upon how the phase noise is simulated and the frequency offset from the radar echo signal.