Error Analysis of Polarimetric Interferometric SAR under Different Processing Modes in Urban Areas
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摘要: 极化干涉合成孔径雷达(PolInSAR)在城区等复杂场景下的应用受到了越来越多的关注。面向城区的极化干涉SAR处理主要包括基于极化最优相干的干涉测高、基于极化分解的干涉测高、联立极化干涉观测方程直接求解不同散射机制高度这3种模式。现有研究对各类误差在极化干涉SAR不同处理模式下的综合影响分析尚很欠缺。该文在构建极化干涉SAR误差模型的基础上,提出了联立极化观测方程下散射机制的求解方法,推导了极化失真和干涉误差在极化干涉SAR不同处理模式下的综合影响模型,并通过仿真验证了模型的正确性,同时给出了3种处理模式补偿误差后的高度反演结果,补偿误差后通过极化最优相干得到建筑区域高度的均方根误差(RMSE)为2.77 m。在此基础上,通过仿真给出了极化干涉SAR不同处理模型下的误差影响曲线,比较了不同处理模型受误差影响的程度,并给出了合理解释,研究结果为极化干涉SAR系统设计、处理方法选择及数据应用提供了参考。
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关键词:
- 极化干涉合成孔径雷达 /
- 误差分析 /
- 极化最优相干 /
- Pauli分解 /
- ESPRIT分解
Abstract: Polarimetric Interferometric Synthetic Aperture Radar (PolInSAR) simultaneously has interferometric height measurement and full-polarized detection capabilities, which can better reflect the structural properties of feature targets. Therefore, its potential for application in complex scenarios, such as urban areas, has attracted increasing attention. In urban areas, the processing mainly includes three modes: using interferometry to extract height based on polarimetric optimal coherence, using interferometry based on polarized decomposition, and associating polarimetric interferometric observation equations to retrieve the heights of different scattering mechanisms. The analysis of error factors and effects on Interferometric SAR (InSAR) and polarized SAR is almost complete, but the analysis of error effects under different processing modes of PolInSAR is insufficient. Based on the PolInSAR error model, our paper proposes a method for solving the scattering mechanism under the simultaneous polarization observation equation. Moreover, we derive the model including each error under different processing modes in PolInSAR from the aspect of polarized errors, interferometric errors, and the Signal-to-Noise Ratio (SNR). Furthermore, the model is verified through simulations, and we provide height inversion results through three processing modes after compensating for polarized errors and interferometric errors. After the error compensation, we obtain a Root Mean Squared Error (RMSE) in building areas of 2.77 m through polarimetric optimal coherence. Finally, the simulations provide the error impact curves under different processing modes of PolInSAR and compare the degree of different processing methods affected by errors, which provides a reasonable explanation for the design of the PolInSAR system, selection of processing methods, and data application. -
表 1 系统仿真参数
Table 1. Simulation parameters of system
参数 数值 中心频率 15.2 GHz 飞行高度 205 m 斜距 889 m 基线 0.6 m 基线角 –1° 表 2 ESPRIT方法得到散射机制的结果
Table 2. Scattering mechanisms obtained by ESPRIT
极化方式 主图像 辅图像 含串扰的
主图像含串扰的
辅图像单次散射 –0.89
+0.11i–0.85
–0.25–0.54
+0.03i–0.45
–0.33i0°二次散射 0.02
–0.01i0.02
–0.01i0.02
+0.01i0.02
+0.01i45°二次散射 1 1 1 1 表 3 ESPRIT方法得到的干涉相位
Table 3. Interferometric phase obtained by ESPRIT
极化方式 理想(°) 含串扰(°) 单次散射 58.90 58.41 45°二次散射 84.87 84.24 表 4 Pauli分解得到散射机制的结果
Table 4. Scattering mechanisms obtained by Pauli decomposition
极化方式 主图像 辅图像 含串扰的主图像 含串扰的辅图像 单次散射 0.10 0.29 0.09+0.04i 0.28+0.04i 0°二次散射 0.002 0.001i –0.001i 0.003 45°二次散射 1 1 1 1 表 5 –20 dB串扰误差下两种分解的干涉相位误差
Table 5. Interferometric phase error of two decompositions under –20 dB crosstalk
极化方式 ESPRIT (°) Pauli (°) 单次散射 0.49 15.69 45°二次散射 0.63 –0.45 -
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