时变环境下RCS测量中的精确背景抵消处理技术

在外场雷达散射截面（RCS）测量中，受随时间变化的环境因素影响，不同时刻测得到的数据其幅度和相位不完全相干，导致直接采用背景矢量相减技术难以有效地抑制背景杂波。建立了测量系统-测试场时变传递函数的参数化模型来表征环境变化对雷达接收回波的影响，并在此基础上提出了一种改进的精确背景抵消处理技术。首先，从现场测量回波数据中提取辅助校准区域数据；然后，利用降噪互相关法和优化相干函数法估计出时变传递函数模型参数，并据此对不同时刻测得的回波数据进行幅度和相位补偿，使得两者完全相干；最后，做精确的背景矢量相减处理。实验结果验证了本文技术和算法的有效性。

Exact background subtraction processing technique in RCS measurement in time-variant environment

In outdoor radar cross section (RCS) measurement, background clutter cannot be suppressed effectively using conventional background subtraction technique due to the fact that, influenced by time-variant outdoor environment, the amplitudes and phases of radar received returns collected at different time interval are not perfectly coherent. A parametric model is developed to characterize the effect of such a time-variant environment on radar received returns. Meanwhile, a technique for improved exact background subtraction is proposed based on the parametric model. First, the return data of specified region with an ancillary reference signal available is extracted from the measured return data to estimate model parameters by means of de-noising cross-correlation algorithm and coherence function optimization. Then, the amplitudes and phases of the received signals can be compensated using the time-variant parametric model, so that complete coherence can be achieved. Finally, background subtraction can be implemented on the amplitude and phase compensated data, resulting in exact background subtraction. The experimental results are presented to demonstrate the feasibility and usefulness of the proposed technique.