The railSAR, also known as the ultra-wideband Foliage Penetration Synthetic Aperture Radar (UWB FOPEN SAR), is a rail-guided, low-frequency impulse radar system that can detect and discern target objects hidden behind foliage.[1][2] It was designed and developed by the U.S. Army Research Laboratory (ARL) in the early 1990s in order to demonstrate the capabilities of an airborne SAR for foliage and ground penetration.[3] However, since conducting accurate, repeatable measurements on an airborne platform was both challenging and expensive, the railSAR was built on the rooftop of a four-story building within the Army Research Laboratory compound along a 104-meter laser-leveled track.[1][4]
At the time, the railSAR fell into the highest category of UWB radar systems, operating across a 950 MHz-wide band from 40 MHz to 1 GHz on a pulse strength of 2.5 megawatts.[1][3][4] It provided fully polarimetric, high resolution radar data and possessed 185% bandwidth compared to other radar systems that had less than 25% bandwidth.[1][5]
Applications of the railSAR technology range from military uses such as detecting landmines and stationary targets in hiding for reconnaissance purposes to commercial uses, including cable and pipe detection, oil and water table measurements, and environmental remediation.[6]
^ abcdMcCorkle, John (November 15, 1993). Del Grande, Nancy K.; Cindrich, Ivan; Johnson, Peter B. (eds.). "Early results from the Army Research Laboratory ultrawide-bandwidth foliage penetration SAR". Underground and Obscured Object Imaging and Detection. 1942: 88–95. Bibcode:1993SPIE.1942...88M. doi:10.1117/12.160352. S2CID123322305.
^Ressler, Marc (May 31, 1996). "The Army Research Laboratory ultra wideband BoomSAR". IGARSS '96. 1996 International Geoscience and Remote Sensing Symposium. Vol. 3. pp. 1886–1888. doi:10.1109/IGARSS.1996.516828. ISBN0-7803-3068-4. S2CID62582116.