Characterizing Baseline Configuration Effects on Forest Height Retrieval in Airborne P-Band TomoSAR

Tomographic synthetic aperture radar (TomoSAR) effectively characterizes forest vertical structure, while baseline configuration strongly affects forest height retrieval accuracy. However, systematic baseline analysis is limited by the lack of real multi-baseline datasets with controllable configurations. In this study, the landscape-scale canopy backscatter model (LandSAR) is used to simulate airborne P-band SAR data under different baseline configurations. LandSAR performance is first evaluated against real P-band InSAR data and lidar canopy height. Forest height is then retrieved under a known-ground assumption, and the effects of inter-track baseline spacing, track number, and total aperture length on forest height retrieval are analyzed at different flight altitudes. The results show that retrieval accuracy is governed by the coupled effects of baseline spacing and track number. For small baseline spacings, accuracy improves with increasing track number, but the improvement remains limited. Larger spacings improve retrieval performance, whereas overly large spacing or aperture may reduce the height ambiguity margin and reconstruction stability. The optimal accuracies are 4.72 m, 4.58 m, 4.52 m and 4.48 m at flight altitudes of 3000 m, 3500 m, 4000 m and 4500 m, respectively. This study provides a physically interpretable reference for airborne P-band TomoSAR configuration design.