基于轨道误差搜索的双基地ISAR包络对齐算法

针对空间目标这一应用背景提出了一种基于轨道信息的双基地逆合成孔径雷达包络对齐算法。首先推导了空间目标位置预报误差与慢时间之间的函数关系,分析表明,成像时间内轨道预报误差可用慢时间的二阶函数表示。在此基础上,利用轨道预报值和轨道误差搜索结果通过在频域补偿相位的方式完成了一维距离像包络的精确对齐。参数搜索过程中,确定了误差速度和加速度的搜索步进量,并以二维图像的对比度作为代价函数。仿真结果表明,相比于传统基于回波相关性的包络对齐算法,该算法更适用于因双基地角和极化失配等因素导致信噪比较低的双基地回波。

Bistatic ISAR envelope alignment algorithm based on orbit error search

Aiming at the application of space objects, a bistatic inverse synthetic aperture radar envelope-alignment-algorithm based on orbit information is proposed. Firstly, the relationship between the orbit position prediction error and the slow time is deduced, the analysis shows that the orbit prediction error in imaging time can be expressed by the second order function of slow time. On this basis, the precise envelope alignment of the one-dimensional range profile is achieved by compensating the phase in the frequency domain using the orbit prediction value and the orbit error search result. In the process of parameter search, the searching step of error velocity and acceleration is determined, and the contrast of the two-dimensional image is taken as the cost function. The simulation results show that the proposed algorithm is more suitable for bistatic echo with lower signal-to-noise ratio due to bistatic angle and polarization mismatch, compared with the traditional envelope alignment algorithm based on echo correlation.