3D Multi-static SAR System for Terrain Imaging Based on Indirect GPS Signals

Yonghong Li, Chris Rizos, Eugene Donskoi, John Homer, Bijan Mojarrabi

School of Information Technology and Electrical Engineering, University of Queensland, Bris-bane QLD 4072, Australia.
School of Surveying and Spatial Information System, University of New South Wales, Sydney NSW 2052, Australia.

DOI:                 

Abstract

A 3D multi-static SAR imaging system which utilises reflected GPS signals from objects on the Earth's surface is described in this paper. The principle of bistatic radar is used to detect movement of, or changes to, the imaged object. The indirect GPS signals are processed by a match filter with the aim of improving the spatial resolution of detection. The measure of spatial resolution of this imaging system is derived, and is confirmed by MATLAB simulation. Several scenarios are considered, for the visible satellite at a given receiver and object location. The scenarios for different satellites are: a) static receiver with two targets which move with the same speed; and b) moving receiver with one static target and one moving target. Simulation results show that the spatial resolution of detection depends on the relative positions of the GPS satellites, the imaged objects and the GPS receiver, as well as their respective velocities.

Keywords

Detection, Imaging, GPS, SAR

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Armatys M., et al (2000), Exploiting GPS as a New Oceanographic Remote Sensing Tool, National Technical Meeting of the U.S. Institute of Navigation, Anaheim, California, 26-28 January, 339-347.
[2]	Komjathy A., et al (2001), Developments in Using GPS for Oceanographic Remote Sensing: Retrieval of Ocean Sur-face Wind Speed and Wind Direction, National Technical Meeting of the U.S. Institute of Navigation, Long Beach, California, 22-24 January.
[3]	Martin-Neira M., et al(2001), The PARIS Concept: An Experimental Demonstration of Sea Surface Altimetry using GPS Reflected Signals, IEEE Trans. on Geosci. & Remote Sensing, 39(1), 142-150.
[4]	Garrison J.L, et al (2002), Wind Speed Measurement Using Forward Scattered GPS Signals, IEEE Trans. on Geosci. & Remote Sensing, 40(1), 50-65.
[5]	Zavorotny V.U. & A.G. Voronovich (2000), Scattering of GPS Signals from the Ocean with Wind Remote Sensing Application, IEEE Trans. on Geosci. & Remote Sensing, 38(2), 951-964.
[6]	Komjathy A., et al (2000), Towards GPS Surface Reflection Remote Sensing of Sea Ice Conditions, Sixth Int. Conf. on Remote Sensing for Marine & Coastal Environments, II: 447-456.
[7]	Masters D., et al (2000), GPS Signal Scattering from Land for Moisture Content Determination, Proceedings of IEEE International Geoscience. & Remote Sensing Symposium, vol.7: 3090-3092.
[8]	Garrison J.L. & S.J. Katzberg (1997), Detection of Ocean Reflected GPS Signals: Theory and Experiment, IEEE Southeastcon Blacksburg'97 Engineering New New Century, USA, 12-14 April, 290-294.
[9]	Zavorotny Z.U., et al (2000), Extraction of Sea State and Wind Speed from Reflected GPS Signals: Modeling and Air-craft Measurements, IEEE Int. Geosci. & Remote Sensing Symposium, 4: 1507-1509.
[10]	Komjathy A., et al (1998), GPS Signal Scattering from Sea Surface: Comparison Between Experimental Data and Theoretical Model, Fifth Int. Conf. on Remote Sensing for Marine & Coastal Environments, 1: 530-539.
[11]	Komjathy A., et al (2000), GPS Signal Scattering from Sea Surface: Wind Speed Retrieval Using Experimental Data and Theoretical Model, Remote Sensing of Environment, 73, 162-174.
[12]	Lin B., et al (1998), The Relationship Between the GPS Signals Reflected from Sea Surface and the Surface Winds: Modeling Results and Comparisons with Aircraft Measurements, J. of Geophysical Research - Oceans, 104(C9), 20713-20727.
[13]	Elfouhaily T. & C. Zuffada (2000), On Deriving Near-Surface Wind Vector Information from GPS Ocean Reflections: Simulation and Measurements, IEEE Int. Geosci. & Remote Sensing Symposium, 7: 3081-3083.
[14]	Lowe S.T., et al (2000), An Ocean-Altimetry Measurement Using Reflected GPS Signals Observed from a Low-Altitude Aircraft, IEEE Int. Geosci. & Remote Sensing Symposium, 5: 2185-2187.
[15]	Willis N.(1991), Bistatic Radar, Artech house Inc., Norwood.