Passive Bistatic Ground-Based Synthetic Aperture Radar: Concept, System, and Experiment Results

Abstract

A passive bistatic ground-based synthetic aperture radar (PB-GB-SAR) system without a dedicated transmitter has been developed by using commercial-off-the-shelf (COTS) hardware for local-area high-resolution imaging and displacement measurement purposes. Different from the frequency-modulated or frequency-stepped continuous wave signal commonly used by GB-SAR, the continuous digital TV signal broadcast by a geostationary satellite has been adopted by PB-GB-SAR. In order to increase the coherence between the reference and surveillance channels, frequency and phase synchronization of multiple low noise blocks (LNBs) has been conducted. Then, the back-projection algorithm (BPA) and the range migration algorithm (RMA) have been modified for PB-GB-SAR to get the focused SAR image. Field experiments have been carried out to validate the designed PB-GB-SAR system and the proposed methods. It has been found that different targets within 100 m (like the fence, light pole, tree, and car) can be imaged by the PB-GB-SAR system. With a metallic plate moved on a positioner, it has been observed that the displacement of the target can be estimated by PB-GB-SAR with submillimeter accuracy.

Indoor Experiments of Bistatic/Multistatic GB-SAR with One-Stationary and One-Moving Antennae

“…Multiples can be seen in azimuth direction due to azimuth ambiguity. This happened because we have not imposed the restriction of the coherent integration length due to the beam width, as shown in Equation (12). This was done intentionally to check if the azimuth step interval is small enough to avoid azimuth ambiguity in the image area of interest.…”

“…Ground-based synthetic aperture radar (GB-SAR) systems have been widely used to simulate various satellite/airborne SAR configurations for the next generation as well as its own use for ground imaging and surface change detection. Various interferometric [9][10][11][12] and tomographic SAR [13][14][15][16] have been successfully tested in GB-SAR systems owing to the highly accurate repeatability and versatile system operability. Krysik et al [17] tested a bistatic GB-SAR configuration as a combination of GB-SAR and satellite.…”

Analysis of a Bistatic Ground-Based Synthetic Aperture Radar System and Indoor Experiments

“…A limited number of papers have reported the use of GB-SAR for bistatic configurations such as the use of a GB-SAR as a passive receiver and a satellite SAR as a trans-mitter [12] and the use of a ground-based transponder to redirect a transmitting signal to obtain the target's two-dimensional displacement vector [13].…”

An Image Formation Algorithm for Bistatic SAR Using GNSS Signal With Improved Range Resolution

“…The separation of passive Bi-SAR system transmitter and receiver yields several configuration using different types of transmitters or receivers, including spaceborne, airborne, ground-based system [1]- [3]. Many different types of available illuminators of opportunity can be utilized as the transmission, such as digital audio broadcasting(DAB) [4], Digital Video Broadcasting Terrestrial(DVB-T) [5]- [10], WiFi [11], DTV [12], [13], and Global Navigation Satellite Systems (GNSS) [14]- [21]. The advantages of passive bistatic radar include low cost, free license, silence working and environmental friendly, making it feasible in the earth remote sensing fields.…”