宽带雷达目标散射中心类型参数估计性能分析

Performance Analysis for Estimating Type Parameter of Scattering Centers on Wideband Radar Targets

采用几何绕射理论(GTD)模型描述宽带雷达测量数据,其中类型参数α反映散射中心的局部几何特征。通过采用衰减指数和(DE)模型近似GTD模型并推导和化简类型参数估计的克拉美-罗限(CRB),得出可靠鉴别类型参数的条件。结果表明,增大相对带宽是提高散射中心类型参数估计精度的有效手段;另外,鉴别散射中心类型要求非常高的信噪比,在复杂环境下难以实现。最后采用仿真数据和实测数据验证了以上结论。

Wideband radar measurements can be modeled by the geometric theory of diffraction （GTD） and the type parameter a describes the local geometry of scattering centers. Approximating GTD model by the damped exponentials（DE） model, the Cramér-Rao bounds（CRB） is derived and simplified on type parameter estimates and the requirements for correctly identifying type parameter are obtained. Results show that increasing relative bandwidth is the most effective way to improve the estimation accuracy of the type parameter. Moreover, the SNR threshold for correctly identifying type parameter is so high so that it is infeasible in complex environment. Results are verified by simulation and measurement data.