Study On Clutter Suppression Method Of Airborne Radar Under Uniform Acceleration Motion

Airborne radar has the characteristics of wide detection field and strong mobility.It has become an important factor to seize the air supremacy and information supremacy in modern war and determine the outcome of modern war.However,airborne radar is often affected by ground clutter when it works in down looking mode.Space time adaptive processing(STAP)technology can effectively suppress clutter and improve the performance of target detection.In previous studies,the motion of the aircraft in a coherent processing interval(CPI)is often regarded as a uniform linear motion.With the rapid development of high mobility platforms and hypersonic platforms,this assumption is no longer universally applicable.The variable speed movement of the carrier will cause the Doppler frequency of the echo of the target or ground scatterers to change within one CPI,which makes the traditional STAP technology for uniform linear motion airborne radar unable to be directly applied,and brings new challenges to clutter suppression and target detection.Therefore,it is necessary to study the clutter suppression method of variable speed airborne radar.In this paper,the clutter suppression methods of airborne radar in uniform acceleration flight phase ars studied,and three clutter suppression methods for uniform acceleration airborne radar are proposed.The main work can be summarized as follows:1.The signal model of the aircraft with uniform acceleration is studied,and the influence of the aircraft acceleration on the target echo and clutter is analyzed.The limitation of traditional Doppler post reduced-dimension STAP method in processing uniformly accelerated airborne radar echo is analyzed.2.A clutter suppression method of uniform acceleration airborne radar based on interpolation compensation is proposed,which is suitable for the case that the echo will not has Doppler ambiguity.Firstly,the echo data is preprocessed by non-uniform interpolation,which requires that the number of Fourier bases used in the interpolation is much larger than the number of coherent integration pulses.Then the steering vector form of the interpolated target signal is derived,and the Doppler post reduced-dimension STAP method based on interpolation compensation is formed.Finally,the simulation results show that this method can effectively improve the clutter suppression performance of uniform acceleration airborne radar echo without Doppler ambiguity.3.A uniform acceleration clutter suppression method based on beam domain compensation is proposed.In this method,multi-beamforming is used to distinguish echoes from different azimuth in beam domain,and compensate the echo data of different beams to form a clutter suppression method based on beam domain compensation.The simulation results show that this method can effectively improve the clutter suppression performance of uniform acceleration airborne radar echo.4.A clutter suppression method of uniform acceleration airborne radar based on time domain compensation along equal Doppler line is proposed,which is suitable for the case that the echo will not has Doppler ambiguity.Based on the equivalence of equal Doppler line and equal acceleration line,the whole element-pulse domain data is cycled according to the number of Doppler channels,and the whole echo is compensated according to the center frequency of the current Doppler channel in each cycle.Then the compensated data is filtered in time domain,and the Doppler channel data of the current cycle and the data of its adjacent channels are taken out for reduced-dimension STAP.Simulation results show that the method can effectively improve the clutter suppression performance of uniform acceleration airborne radar echo without Doppler ambiguity.