重轨低频超宽带合成孔径雷达干涉测量关键技术研究

The low frequency ultrawide band synthetic aperture radar (UWB SAR)has excellent foliage penetration capability and can detect the objects under the foliage.Therefore, the repeat-pass low frequency UWB SAR interferometry (UWB InSAR)technique can perform topographic mapping of the ground beneath the foliage. However, due to the lower carrier frequency and the larger relative bandwidth ratio as well as the longer synthetic aperture length, several special difficult problems need to be resolved when working with the repeat-pass low frequency UWB InSAR data. The problems includes the phase preserving method of radio frequency inteference (RFI) suppression, the residual motion error correction under the long synthetic aperture length and the filtering preprocessing of spatial coupling wavenumber spectral. In this research, based on the analyses results of the simulated and real data, the higher accuracy math models of the residual motion error and the complicated RFI signal as well as the spatial coupling wavenumber spectral are built, respectively. Then, the resolutions for overcoming above-mentioned problems will be proposed based on the built math models. In the research process, the repeat-pass low frequency UWB SAR raw data will be used for testing the validity of the proposed algorithms. According to the test results, the proposed algorithms will be improved time after time.The research results achieved in this program will help for improving the performance of the repeat-pass low frequency UWB InSAR system on topographic mapping the terrian under the foliage, and promotes the practical application process of the repeat-pass low frequency UWB InSAR technique.

低频超宽带合成孔径雷达（UWB SAR）具有穿透叶簇对丛林隐蔽目标成像探测的能力，因此基于低频UWB SAR的重轨干涉测量技术（UWB InSAR）可对叶簇覆盖下的隐蔽地形进行高精度测绘。然而，由于工作频段低、相对带宽大、合成孔径长等特点，重轨低频UWB InSAR需要解决复杂射频干扰（RFI）的保相抑制、长合成孔径下的残余运动误差补偿、空间耦合波数谱滤波预处理等特殊难点问题。为此，本项目从仿真模拟和实测数据分析着手，建立能够准确描述重轨低频UWB InSAR复杂RFI信号、残余运动误差和空间耦合波数谱的数学模型，然后基于所建模型提出针对上述难点问题的解决方法。研究过程中，将利用重轨低频UWB SAR实测数据对所研究算法的有效性进行反复验证，并根据验证结果对所提算法进行改进和完善。本项目研究将为提高重轨低频UWB InSAR对叶簇隐蔽地形的测绘精度典型基础，推动该项技术的实用化进程。

低频超宽带合成孔径雷达（UWB SAR）具有穿透叶簇探测隐蔽目标的能力，因此重轨低频UWB SAR干涉测量技术（UWB InSAR）可实现叶簇覆盖下隐蔽地形的高精度测绘。然而，由于工作频段低，合成孔径长，重轨低频UWB InSAR需要解决长合成孔径下的高精度成像处理、图像配准、空变射频干扰（RFI）抑制、大尺寸干涉图像相位解缠等难点问题。为此，本项目从已录取的重轨低频UWB SAR实测数据着手，建立了能够准确描述重轨低频UWB InSAR成像几何、空变RFI信号和相位缠绕的数学模型，进而提出了适用于重轨低频UWB InSAR的高精度成像处理方法、空变RFI抑制算法、图像配准及相位解缠算法，最后实现了数字高程图反演。研究过程中，我们利用实测数据对所研究算法进行反复验证，并根据验证结果进行不断改进与完善。本项目取得的研究成果提高了我国在重轨低频UWB InSAR地形测绘方面的研究水平，将有助于推动该项技术的实用化进程。基于项目研究成果，课题组研究人员在IEEE/IET等国际/国内期刊和国际会议共发表学术论文19篇，其中SCI检索10篇，另有2篇论文已分别被《IEEE Transactions on Geoscience and Remote Sensing》和《IEEE Geoscience and Remote Sensing Letters》录用，即将刊出。此外，已申请受理国家发明专利2项。