OVERVIEW AND APPLICATIONS OF UAVSAR's MULTI-SQUINT POLARIMETRIC IMAGING MODE

摘要

NASA's Jet Propulsion Laboratory has developed a reconfigurablernpolarimetric L-band synthetic aperture radarrn(SAR), specifically designed to acquire airborne repeatrntrack interferometric (RTI) SAR data for application tornmonitoring surface deformation and vegetation structurernmeasurements. The system employs a precision autopilotrndeveloped by NASA Dryden that allows the plane to flyrnprecise trajectories usually within a 5 m tube. Also requiredrnfor robust repeat pass applications is the ability tornpoint the antenna in the same direction on repeat passesrnto a fraction of an azimuth beamwidth (8u000e for UAVSAR).rnThis precise pointing is achieved using an electronicallyrnscanned antenna whose pointing is based on inertial navigationrnunit (INU) attitude angle data. The radar design isrnfully polarimetric with an 80 MHz bandwidth (2 m rangernresolution) and has a greater than 20 km range swathrnwhen flying at its nominal altitude of 12500 m. The abilityrnto electronically steer the beam on a pulse-to-pulsernbasis has allowed a new mode of SAR data acquisitionrnwhereby the radar beam is steered to different squint anglesrnon successive pulses thereby simultaneously generatingrnimages at multiple squint angles. This mode offersrnthe possibility of generating vector deformation measurementsrnwith a single pair of repeat passes and to obtainrngreater k_z diversity for vegetation studies with a reducedrnnumber of passes. This paper will present an overview ofrnthe mode, discuss its potential for deformation and vegetation,rnand show some examples using UAVSAR data.