Evaluation of the RPC model as a replacement for the spaceborne InSAR phase equation

Abstract

AbstractSynthetic aperture radar interferometry (InSAR) is an alternative to conventional stereoscopic SAR for extracting relative or absolute terrain elevation information. However, for different InSAR data‐sets, the auxiliary parameters are different, which introduces differences in the SAR interferometry rigorous sensor model (RSM). The Rational Polynomial Coefficient (RPC) model is a generalised sensor model which makes full use of the auxiliary parameters of the satellite images, and the coefficients of the model are then solved by fitting the model to the RSM. Some work has been carried out previously to validate its substitutability for the SAR RSM, which is based on the Range–Doppler equations. Further, this paper aims to prove that the RPC model can also be used as a replacement for the InSAR phase equation and can be widely applied on different types of InSAR data‐sets. Based on numerous tests, the modelling error of the RPC is analysed. This study found that the RPC model is suitable for InSAR data‐sets and it can be used as a replacement for the phase equation.