Polarimetric SAR Interferometry Forest Height Inversion Error Model: The Impact of the Nonideal System Parameters

The model-based polarimetric interferometric synthetic aperture radar forest height inversion is inherently affected by nonideal system parameters, including channel imbalance, crosstalk, and noise. To investigate the impact of nonideal system parameters on the estimated forest height, this article introduces an analytical forest height inversion error model based on the two-layer randomly oriented volume over ground model. First, the error transfer function is derived to present the forest height error caused by the disturbance of the volume coherence. Then, the coupled effects of the nonideal system parameters on the volume coherence are established and demonstrated to reduce the amplitude of the volume coherence. The effects of channel imbalance and crosstalk are explicitly derived and found to be coupled together to amplify the noise. Finally, the error model is established by combining the error transfer function and the disturbance of the volume coherence caused by the nonideal system parameters. The proposed error model is verified by simulation analyses on real airborne repeat-pass BioSAR 2008 datasets. The results demonstrate that the proposed model can accurately capture the relationship between the height estimation errors and the system parameters.