Research On The Clutter Suppression For Hypersonic Vehicle-borne Forward-looking Radar

As one of the front directions of the 21th-century aviation and space industry, the hypersonic vehicle(HSV) has attracted much attention from military major powers around the world. Meanwhile, it has a promising application prospect in both civil and military filed, which makes it important to conduct research on detection techniques of ground slow targets with the HSV-borne radar.As is known, the airborne radar encounters strong ground clutter when detecting ground target, which makes it necessary to effectively suppress the ground clutter to improve the detection performance. With regard to the HSV-borne forward-looking radar, there exist serious Doppler and range ambiguities. Besides, clutters of different distances have the characteristic of distance non-uniform. The above factors make the traditional Pulse Doppler(PD) disabled to suppress clutter and distinguish targets and clutter. The space-time adaptive processing(STAP) generalizes the basic theory of adaptive array signal processing in the two-dimension data filed consisting of sampling array elements and pulses. Though STAP can effectively restrain ground clutter of airborne radar, it encounters several problems applied for HSV. These problems include range and Doppler ambiguities brought from high speed and mobility and range non-uniform of forward-looking radar.According to the above background, this paper focuses on the study of suppressing clutter of HSV-borne forward-looking radar. Firstly, the characteristics of ground clutter of HSV-borne radar, which include the of clutter migration, range-Doppler, and space-time features. Besides, a selection criterion of pulse repeated frequency is introduced according to the analyzed clutter characteristics. Then, the reason is discussed that STAP rather than PD is adopted for clutter suppression in HSV. Also, the simulation experiments are conducted to verify our standpoint. Thirdly, a clutter suppression method is proposed, which is suitable for HSV-borne forward-looking radar. The array elevation information is first used to filter clutter with range ambiguity. After that, each range cell only contains clutter with linear ambiguity. Then, with the use of the registration based compensation method and the steering vector based least squares method, the range non-uniform is compensated for the filtered data, respectively. Both of two compensation methods outperform the method of Doppler frequency shift and angle-Doppler compensation. Finally, the residual clutters are restrained by STAP. Even with the existence of amplitude-phase error, the performance of proposed method can barely be influenced. Furthermore, experiment results validate the proposed method.