Bistatic Synthetic-Aperture Imaging Using GPS Reflections

We present results of a program to create SAR-like images using GPS reflected signals. This technique can be used as a relatively inexpensive remote-sensing tool. Imaging resolution as a function of geometry and antenna characteristics will be presented. Imaging data were recorded over Lake Casitas, near Santa Barbara, CA, over a nearby shoreline, and over the open ocean using a Cessna 310 flying at 10000' elevation. The GPS signals were collected using an open-loop recorder operating at 20 MHz, and were processed using a software GPS receiver. The receiver output is further processed by a custom SAR-like processor to form images in the forward scattering direction.