机载双基预警雷达目标探测系统具有较高的安全性和稳健的探测性能,但其非理想探测构型会造成杂波的非平稳性。传统自适应角度多普勒补偿(A2DC)方法对每个距离门的杂波数据进行空-时两维谱中心的估计,能够有效地补偿双基杂波因复杂构型引入的非平稳误差。然而,当回波中有较强的目标干扰信号时,自适应角度多普勒补偿方法会错误地估计该距离门杂波信号的空-时中心频率,造成目标信号产生相消现象。针对该问题,文中提出一种基于改进的A2DC的双基杂波谱补偿方法。所提方法将自适应角度多普勒补偿和广义内积法相结合,在杂波非平稳误差初步补偿之后剔除含有“疑似目标”的非均匀距离样本;并用该距离门附近样本的杂波谱中心估计参数构成相应的补偿矩阵,对该距离单元杂波数据进行角度-多普勒域的谱误差精确补偿;最终根据双基杂波非平稳误差精细化补偿后的样本数据,实现地理杂波的有效抑制,且有效避免了动目标信号因空域相消导致信杂噪比严重降低的问题。机载双基雷达杂波抑制和动目标检测的仿真实验结果表明,所提方法在面对多目标信号干扰时具有优良的双基杂波距离依赖补偿效果,从而完成稳健的地理杂波对消和动目标信号的可靠探测。

Airborne bistatic early warning radar system has high safety and robust moving target detection performance. However, the non-ideal configuration of airborne bistatic early warning radar can cause the non-stationary of ground clutter. Traditional adaptive angle Doppler compensation (A2DC) can estimate the space-time two-dimensional spectral centers of the multi-channel clutter data corresponding to each range gate and effectively compensate the non-stationary errors introduced by the complex observation configuration. However, when there is a strong target interference signal in the radar echo, the adaptive angle Doppler compensation method may incorrectly estimate the space-time center frequency of clutter signal, resulting in the target signal cancellation phenomenon. To solve this problem, in this paper a bistatic clutter spectrum compensation method based on improved A2DC is proposed. The proposed method combines the adaptive angle Doppler compensation technique with the generalized inner product (GIP) method to eliminate the heterogeneous range samples containing the "suspected targets" after the initial compensation of the clutter non-stationary property. By using the compensation matrix constructed by the estimated clutter spectrum center parameters of the range sample data near the range gate under test, the spectral error of the clutter data containing the "suspected targets" can be accurately compensated in the angle-Doppler domain. Finally, due to the fine compensation of non-stationary errors of bistatic clutter, the effective suppression of geographic clutter is realized, and the signal noise ratio degradation issue caused by spatial cancellation of moving signals is effectively avoided. The simulation results of an airborne bistatic radar system show that the proposed method has excellent bistatic clutter range-dependent compensation performance even in the case of multi-target signal interference,thus achieving robust geographic clutter cancellation and reliable moving target detection capability.

TN959. 73;TN957. 51

国家自然科学基金面上资助项目(62171272);中国航天科技集团公司第八研究院产学研合作基金资助项目(USCAST2021-15 和USCAST2022-21);上海航天科技创新基金资助项目(SAST2019-071)