Global Positioning Systems (GPS) Use for Interferometric Radar Validation and Geometric Correction

The 1996 INDonesian Radar EXperiment (INDREX) Campaign studied several types of highresolution (1.5 meter) Dornier Synthetic Aperture Radar (DO-SAR) data/images, e.g. intensity, coherence, and interferometric. The campaign was sponsored by the European Space Agency (ESA) and facilitated by the Indonesian Ministry of Forestry and Wageningen University. The campaign was directed to develop a ”Remo te Sensing Monitoring System for Forest Management and Land Cover Change in Indonesia". The radar group at the Department of Environmental Sciences, Wageningen University has several research activities to investigate radar tree mapping and data integration, and one of them is the study of “Global Positioning Systems (GPS) Use for Interferometric Radar Validation and Geometric Correction”. The objective of this study is to validate the height data derived from the orthorectified interferometric SAR (InSAR) data/images and to understand the errors produced by the conventional geometric correction process using available commercial Remote Sensing (RS) and Geographic Information Systems (GIS) software (e.g. ENVI and Arc/Info). The results showed that the height of 3D Differential GPS (DGPS) data was agreed with the height of InSAR data both in the line form and values, but the height of 3D absolute positioning GPS data was only agreed in the line form. This study learned that a good positional accuracy radar data needed further validation investigations to locate the precise position of an individual tree.