GEOGRAPHIC SYNTHETIC APERTURE RADAR (GEOSAR) – A NEW GENERATION RADAR SYSTEM SUITABLE FOR GEOSCIENCE APPLICATIONS IN THE ASIA-PACIFIC REGION

摘要

GeoSAR is a new-generation airborne radar system designed for precision mapping of terrain attributes and landcover inventory in tropical, temperate and arid environments. Engineered by NASA-JPL its development builds on the highly successful, scientific achievements of polarimetric and interferometric datasets collected during airborne AIRSAR missions and Space Shuttle radar programs. Currently operated by EarthData International (USA) for civilian and military uses, GeoSAR is configured to record in a single pass, simultaneous X- and P-band, dual polarimetric, interferometric data in two 10 km wide swaths on the left and right sides of the Gulfstream jet aircraft at an altitude of 10 km above the ground level. In tree-covered terrain, DEMs and ortho-rectified radar reflectance maps are generated near the tops of tree canopy and beneath the foliage, whilst in a dry-soil environment, surface and sub-surface geometries will be observed. The modelling of bald-earth DEMs from the combined X- and P-band data will be enhanced by a co-mounted LIDAR system to provide precise ground control points to calibrate the DEMs and simplify the mosaicking process of adjacent flightlines of data. In addition, the LIDAR will add valuable information about tree canopy structures that together with the polarimetric detail from P-band will enable calculations of timber volumes or biomass. Deployment of GeoSAR is scheduled for January-February 2006 to coincide with the dry season in east and south-east Asia providing optimum definition of archaeological sites in the medieval arc of countries from Sri Lanka to Myanmar, Thailand, Cambodia, Vietnam, Malaysia and Indonesia. In addition, GeoSAR data will be most useful for modelling the regional impact of natural disasters such as flooding, lahars and landslides. Entry into Australia and New Zealand will be driven by the support of discipline and commercial groups wanting to apply these data to applications including topographic mapping, trafficability analyses, land-use planning, design of transportation routes, forest inventory, wetland mapping and floodplain management.