双基线TanDEM-X InSAR数据的森林高度反演

Forest height inversion based on dual-baseline TanDEM-X InSAR data

森林高度是进行森林资源管理的重要基础数据,通常使用RVoG模型并结合PolInSAR技术获取,然而目前的PolInSAR数据均通过重轨飞行方式采集,不利于大范围、高精度森林高度测绘。TanDEM-X数据无时间去相干与大气干扰,为森林高度测绘提供了合适的数据来源。但TanDEM-X InSAR数据主要为单极化模式,由于观测信息不足,不满足RVoG模型的解算要求。因此,文中利用双基线TanDEM-X InSAR数据反演森林高度。该方法考虑地形影响采用S-RVoG模型反演森林高度,首先仅使用S-RVoG模型相干性信息建立关系,并通过双基线下相位信息之间的关系进行约束。反演森林高度依赖于消光系数的选择,依据模型相干性对森林高度的敏感性进行分析,并利用LiDAR数据作为先验信息进行消光系数的选择。为了验证本方法,采用了瑞典与西班牙实验区数据进行双基线森林高度反演并利用实验区存在的LiDAR树高数据验证方法的精度,两实验区精度分别为1.86 m与2.43 m。

Forest height is an important basic data for forest resource management.It is usually obtained by using the RVoG model combined with PolInSAR technology.However,the current PolInSAR data are collected by repeated orbital flight mode,which is not conducive to large-scale and high-precision forest height mapping.TanDEM-X data is free of temporal decoherence and atmospheric interference,providing a suitable data source for the mapping of forest heights.However,the TanDEM-X InSAR data are mainly single polarization mode,which does not meet the solution requirements of the RVoG model due to insufficient observational information.Therefore,this paper uses the dual-baseline TanDEM-X InSAR data to invert the forest height.The S-RVoG model is used to invert the forest height considering the influence of terrain.First,only the coherence information of the S-RVoG model is used to establish the relationship,and it is constrained by the relationship between the phase information under the dual baselines.The inversion of forest height depends on the selection of extinction coefficient.This paper analyzes the sensitivity of forest height based on model coherence,and uses LiDAR data as a priori information to select extinction coefficient.In order to verify the method in this paper,data from experimental areas in Sweden and Spain were used for the double-baseline forest height inversion,and the LiDAR tree height data existing in the experimental area was used for verification.The accuracy of the two experimental areas is 1.86 m and 2.43 m respectively.