Performance sensitivities of position and velocity determination using SAR vision guidance update

The authors formulate a synthetic aperture radar (SAR) vision guidance update (VGU) method which utilizes two SAR spotlight images of a common ground location to determine changes in perspective of round features between two different look angles. From the perspective changes, precision platform velocity and position estimates are made relative to any feature in either image. To evaluate the VGU method, the authors developed a simulation which utilizes SAR system parameters and inaccurately known data collection parameters to map object or terrain feature ground positions into SAR image positions. Feature image positions for two different aperture locations are passed to the VGU algorithm, which estimates platform position and velocity. A sensitivity analysis of the VGU method to various system and collection parameters was made using this simulation. Results indicate that SAR image resolution is a dominant effect. It is found that position and velocity estimation within 0.2% are achievable using the authors´ SAR VGU algorithm