星载雷达由于其探测范围广、距离远、全天候等优点，在预警防御系统中占有十分重要的地位。然而，由于观测平台的高速运动以及摄动干扰、传感器观测非线性等问题，使得星载雷达目标高精度跟踪带来严峻挑战。针对星载雷达非线性状态估计问题，采用一种基于变分贝叶斯的非线性滤波方法，该方法通过将非线性状态估计问题转化为优化问题，通过迭代优化获得了闭环解析解。此外，针对坐标变换中俯仰角量测缺失问题，提出了一种基于先验目标高度的俯仰角估计方法。通过数值仿真，验证了所提方法较传统非线性滤波方法，如扩展卡尔曼滤波、不敏卡尔曼滤波、转换量测卡尔曼滤波，具有更好的估计精度。
Spaceborne radars play an important role in early warning defense systems because of their unique advantages such as wide detection range, long distance and all-weather surveillance capability. Due to the high-speed movement of the platform and the strong nonlinear observation function, high-accuracy target tracking for spaceborne radars is difficult. In this paper, we propose a variational Bayes-based nonlinear filtering method, which transforms the nonlinear state estimation problem into an optimization problem. The analytical solution is obtained via a closed-loop iteration manner. Moreover, a pitch angle estimation method is presented using the a priori information of target height. Simulation results show that, compared with the extended Kalman filter, unscented Kalman filter, and the converted measurement Kalman filter, the proposed variational Bayes-based nonlinear filtering method achieves the best estimation accuracy.
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