A New RD-RFM Stereo Geolocation Model for 3D Geo-Information Reconstruction of SAR-Optical Satellite Image Pairs

Niangang Jiao,Hongjian You,Feng Wang

doi:10.1109/access.2020.2991199

Abstract

Nowadays, numerous earth-observation data are obtained from different kinds of platforms, in which data from synthetic aperture radar (SAR) sensors and optical sensors account for the vast majority. They have been widely used in different fields such as 3 dimensional (3D) geo-information reconstruction, object recognition and others. Researchers have investigated the suitability of the rational function model (RFM) for 3D geo-information production with stereo SAR-optical images. Compared with optical remote sensing data, parameters of the RFM for satellite SAR images are not provided to users in most cases, which increases the workload of users applying the SAR-optical stereo geolocation based on RFM. Moreover, the fitting accuracy of RFM to the Range Doppler (RD) model, which is considered as the rigorous sensor model for SAR imagery, do not always meet the requirements. Therefore, a new RD-RFM stereo geolocation model by integrating the RD model of SAR images with the RFM of optical images are proposed for 3D geo-information reconstruction with SAR-optical stereo image pairs. Experiments are conducted based on dataset from Gaofen-3 (GF-3) SAR satellite and Gaofen-2 (GF-2) optical satellite covering urban and mountainous areas in Xinyi City and Dengfeng City, Henan Province, China, respectively. Results indicated that our proposed model can achieve the best performance with different terrain and different convergence angle of stereo SAR-optical image pairs. Compared with the traditional stereo geolocation model based on the RFM for both SAR and optical data, our proposed model is more concise and efficient for the production of 3D geo-information with stereo SAR-optical image pairs, and it's easy to be implemented for users.

Highlights

With the improvement of quality and quantity of earth observation data from space-borne satellites, many researchers have investigated the potential use of them, in which the three dimensional (3D) geo-information is a key product for the applications of obtained datasets
A traditional rational function model (RFM) for synthetic aperture radar (SAR)-optical stereogrammetry is applied based on the produced rational polynomial coefficients (RPCs) of SAR images
Three stereo image pairs covering an urban and mountainous area in Henan Province, China are involved in our experiments, and the results indicated that our proposed Range Doppler (RD)-RFM model can achieve the best performance with different terrain

Summary

INTRODUCTION

With the improvement of quality and quantity of earth observation data from space-borne satellites, many researchers have investigated the potential use of them, in which the three dimensional (3D) geo-information is a key product for the applications of obtained datasets. We proposed a new RD-RFM model for SAR-optical stereogrammetry which is suitable and applicable both in mountainous and urban areas In this model, parameters including orbit information of SAR satellite images and RPCs of optical satellite imagery, all come from supplementary files provided by image vendors. According to the Range Doppler model, the geolocation accuracy of SAR imagery is influenced by the following aspects: satellite orbit error, systematic time delay error, atmospheric propagation delay error, the doppler frequency error and the target elevation error [22]. According to the previous analysis, the geolocation accuracy of SAR imagery is mainly influenced by the satellite position and velocity error, the internal and atmospheric propagation delay error and the target elevation error.

RD-RFM STEREO GEOLOCATION MODEL

EXPERIMENTAL DATASET

CONCLUSION