Radargrammetric parameter evaluation of an airborne SAR image

Digital synthetic aperture radar (SAR) images are composed of lines oriente d along-track and pixels in a cross-track direction. Because of the motion of a SAR platform, the flight position and velocity parameters have time-de pendent characteristics. Our objective consists in devising a model for the position/ velocity parameters, then incorporating the model into radargram metric data processing. The interpolative parameter model is based on a lin ear prediction method with filtering. For a monoscopic airborne SAR image having a 12.0-km swath width and a 9.0- km along-track distance at an altitude of about 7.1 km, the positional root -mean-square errors are calculated using the ground coordinates available a t 15 independent check points. Taking into account any model inadequacy, th e errors inherent in the SAR image forming, and the image point measurement errors, the position accuracy values amount to +/-1.5, +/-1.5 pixels horiz ontally and +/-1.2 pixels vertically.