Bistatic spaceborne-airborne forward-looking SAR

This paper demonstrates and analyzes the imaging capability of a passive airborne forward-looking SAR in combination with a spaceborne illumination system. Without doubt, a forward-looking SAR system has a multitude of applications like navigation and landing assistance for aircrafts. In the past, the realization of such a system on one platform suffered from poor imaging conditions in forward direction due to left/right ambiguities and poor Doppler resolution. Using a bistatic system with a spatially separated transmitter and receiver, the image ambiguities can be avoided and the Doppler resolution can be significantly improved. To our knowledge this paper presents the worldwide first bistatic SAR experiment to demonstrate the capability and feasibility of imaging in forward direction. The radar satellite TerraSAR-X has been used as transmitter and the airborne SAR system PAMIR as receiver.