To clarify the optimal interference parameters of microwave pulses to navigation receivers, by analyzing theoretically the tracking loop correlation processing of navigation receiver under microwave pulse interference, a interference classification method was proposed on the basis of the relationship between microwave pulse spectral lines, spread spectrum code spectral lines and coherent integration time, the correlation output power and carrier-to-noise ratio under microwave pulse interference with different parameters was further derived, finally experimental verification was carried out. Theoretical analysis and experimental results show that when the microwave pulse width is greater than or equal to the spreading code period and less than the coherent integration time, a spreading code spectral line is interfered with multiple microwave pulse spectral lines which enters the bandwidth of the coherent integrator, the microwave pulse has the best interference effect on navigation receivers, and is better than continuous wave interference; with the increase of the number of interference spectral lines, the correlation output power is increased, the carrier-to-noise ratio is decreased, and the interference effect is enhanced.

In terms of the problem that SAR (synthetic aperture radar) in UAV (unmanned aerial vehicle) is easy to be attacked by HPM (high-power microwave) weapons in the complex electromagnetic environment of the battlefield, the field-circuit joint simulation of high-power microwave front-gate coupling of UAV′s SAR was carried out. Model of the SAR′s antenna was established in the CST (computer simulation technology) software. Model of antenna was irradiated with a pulse-modulated sinusoidal signal to simulate the HPM signal, and the antenna port coupling voltage waveform was collected. Antenna port coupling voltage signal obtained in the CST software was injected into the RF (radio frequency) front-end circuit model of SAR, which fully simulated the coupling process of high-power microwave signal from field to circuit. Simulation results show that the low noise amplifier in the RF front-end circuit of SAR is the main target of HPM signal damage, and the spike leakage power of the limiter will threaten the low-noise amplifier of the post-stage circuit. Through simulation, the evaluation diagram of the coupling effect of high-power microwave front door of UAV on-board SAR is obtained.