Repeat-pass SAR Interferometry Experiments with Gaofen-3: A Case Study of Ningbo Area

TL;DR

This study demonstrates the capability of Gaofen-3 satellite for repeat-pass SAR interferometry, producing high-quality digital elevation models with about 5m accuracy in urban areas and 22m in mountainous regions.

Contribution

The paper introduces an effective processing method for Gaofen-3 SAR data, achieving high coherence and accurate DEM generation in diverse terrains.

Findings

Achieved coherence up to 0.88 in urban areas

Produced DEM with about 5m RMS accuracy in plains

Demonstrated Gaofen-3's strong interferometric capabilities

Abstract

This paper reports the repeat-pass interferometric SAR results of Gaofen-3, a Chinese civil SAR satellite, acquired in November 2016 and March 2017 from Ningbo area. With the spatial baseline about 600 m and time baseline 116 days, the coherence of the two images still achieve good enough to generate the digital elevation model (DEM). During the InSAR processing, we compared several baseline estimating methods and obtained a good flat-earth phase removed interferogram map. By using the latest SAR interferogram filter and phase unwrapping method we proposed, we improved the coherence up to 0.88 in urban area and obtained a high quality DEM in Ningbo area. In addition, we evaluated the elevation model by comparing with the elevation values extracted from SRTM. And the result shows that accuracy of the elevation map is about 5 m (RMS) in plane area and 22m (RMS) in mountainous region, which demonstrated that Gaofen-3 has the powerful ability of repeat-pass SAR Interferometry.