Motion compensation for a high resolution Ka-band airborne FM-CW SAR

Airborne synthetic aperture radar is a promising new application for FM-CW radars. At the IRCTR, an operational demonstrator system has been developed in order to investigate the practicability of FM-CW SAR and to prove that an FM-CW SAR system can be operated in an efficient manner from a small platform. The platform used to fly the demonstrator system and the integrated navigation system is introduced. In addition, the digitalization and the synchronization regarding the navigation system is addressed. Subsequently, the motion compensation details, especially the squint angle compensation, are explained. The working status of the demonstrator system and the integrated navigation system is proven by the results of an airborne FM-CW SAR campaign. The results obtained during the airborne campaign are presented and the effect of squint angle compensation is shown. The airborne results could not be further improved by applying more sophisticated motion compensation algorithms or auto-focussing techniques. Therefore, it was decided to develop an improved FM-CW front end in order to enhance the FM-CW SAR image quality.