Bistatic SAR Raw Data Acquisition and Imaging with GPS Time-Synchronized Dual ECHO-SAR Systems

A bistatic SAR(synthetic aperture radar) system based on GPS(global positioning system) time synchronization module is proposed in this study. To configure a bistatic SAR system, two GPS time-synchronized SAR transceivers are operated as a moving transmitter and a stationary receiver, respectively. The GPS time synchronization module generates a reference clock of 10MHz and a trigger signal to control the time synchronization of both SAR transceivers for data acquisition. To implement the proposed method, the experimental device consisting of a ready-made GPS-DO(GPS disciplined oscillator) and a self-manufactured GTSM(GPS time synchronization module) was added to the Echo-SAR system, which is a chirp pulse-based radar transceiver. These synchronization modules make it possible to temporally synchronize two same SAR transceivers separated physically. To reconstruct a bistatic SAR image, optimum synchronization parameters were extracted from raw data collected through a field campaign, and an optimized procedure of bistatic SAR signal processing based on the back-projection algorithm was established.