基于SMLRT-GRT-SVD的机载雷达海面慢速小目标信号积累与杂波抑制方法

机载雷达对海面慢速小目标进行积累检测时面临两个主要问题:一是雷达与目标间的相对运动导致距离走动与多普勒扩散，造成目标积累性能下降；二是较强的海杂波能量影响聚焦与检测结果。为了解决上述问题，本文提出了一种基于分段改进位置旋转变换（Segment Modified Location Rotation Transform， SMLRT）、广义拉东变换（Generalized Radon Transform， GRT）以及奇异值分解（Singular Value Decomposition， SVD）的方法（即SMLRT-GRT-SVD）以快速实现信号积累与杂波抑制。首先，设计时间片段划分准则将回波信号均匀分段，分段时保证在每个时间片段中可以忽略由径向加速度造成的二阶距离走动和多普勒扩散；其次，通过SMLRT校正每个时间片段内由径向速度引起的一阶距离走动，并采用傅里叶变换（Fourier Transform， FT）实现每个时间片段内能量的相参积累；再次，利用GRT循迹所有时间片段的能量峰值位置并进行非相参积累；最后，利用SVD在慢时间域进行回波信号分解并剔除杂波对应奇异值，重构后即可实现杂波能量的抑制。本方法采用分段处理与SVD操作，能够快速实现目标能量的聚集并抑制海杂波能量。仿真与实测数据处理结果均表明了所提方法的有效性。 

SMLRT-GRT-SVD Based Sea-Surface Slow and Small Target Signal Integration and Clutter Suppression Method for Airborne Radar

? ?Airborne radar faces two main problems in sea-surface slow and small target integration detection: First， the relative motions between radar and target lead to range walk and Doppler spread， which result in target integration performance degradation. Second， the heavy sea clutter background energy affects the focusing and detection results. To solve the above problems， this paper proposes a method （i.e.， SMLRT-GRT-SVD） based on segmented modified location rotation transform （SMLRT）， generalized Radon transform （GRT） and singular value decomposition （SVD） to quickly realize integration detection and clutter suppression. Firstly， a time division criterion is designed to segment the echo signal evenly， and the second-order range walk and Doppler spread caused by radial acceleration can be ignored in each slice. Secondly， SMLRT is used to correct the first-order range walk of each slice resulted from the radial velocity， and Fourier transform （FT） is conducted to realize the energy coherent integration in each time slice. Thirdly， apply GRT to track the energy peak positions of all time segments and carry out non-coherent integration. Finally， utilize SVD to decompose the echo signal in the slow time domain and eliminate the corresponding singular values of clutter. After reconstruction， the sea clutter energy can be suppressed. In this method， segmenting processing and SVD operation are adopted to quickly achieve the target energy accumulation and suppress the sea clutter energy. Simulation and real data processing results show the effectiveness of the proposed method.