Details of an Imaging System Based on Reflected GPS Signals and Utilizing SAR Techniques

This research endeavor reveals a method for utilizing reflected Global Positioning System (GPS) signals to form an image of targets within a region of interest. The principle is based upon a type of bistatic synthetic aperture radar (SAR) in which a matched filter technique is employed to perform the image reconstruction. A major challenge was the appalling signal to noise ratio associated with the received reflected GPS signals. Moreover, the reconstruction method resulted in an undesirable point spread function (PSF) which degraded the reconstructed image. The entire GPS signal generation and image reconstruction process was simulated as faithfully as possible and it has been demonstrated that a spatial resolution of the order of the GPS L1 frequency (wavelength of 19 cm) is possible. The smeared image obtained due to poor quality PSF was improved by means of a Wiener filter based deconvolution method. An imaging system based on a stationary receiver has been practically demonstrated with the successful identification of a 0.5 m 2 spherical target.