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Proceedings Paper

Focused array radar for real-time imaging and detection
Author(s): Carey M. Rappaport; Denis M. Reidy
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Paper Abstract

The Focused Array Radar (FAR) is a unique time-domain radar system which uses adjustable time delayed signals in a wide multi-element array which focuses transmitted and received signals to detect targets in lossy soil. By making use of specially-designed folded rhombus antenna elements--which are both ultra-wideband and more omnidirectional in the forward direction than a comparable dipole--the FAR optimizes the trade-off between target resolution and penetration depth. These projectory antenna elements, patented by GEO-CENTERS, INC., faithfully radiate sub- nanosecond pulses with frequency response varying from about 700 MHz to 1.3 GHz, so targets in wet soils within 60 cm of the surface and as small as 8 cm can be resolved. The array signals are focused by establishing the time delay from each element to each sample point in the soil medium, taking into consideration the differing propagation speed in air and various soils, as well as ray path refraction at the air/ground interface. These delays are applied in roughly ten picosecond intervals to the transmitted signal and used to time gate the received signal. By using time delays for a focused wideband pulse, the phases of each frequency component of the radar signal are in effect properly specified for constructive interference. Also, as a result of the time-gating, the large ground surface reflection signal is avoided.

Paper Details

Date Published: 17 June 1996
PDF: 12 pages
Proc. SPIE 2747, Radar Sensor Technology, (17 June 1996); doi: 10.1117/12.243083
Show Author Affiliations
Carey M. Rappaport, Northeastern Univ. (United States)
Denis M. Reidy, Geo-Centers, Inc. (United States)


Published in SPIE Proceedings Vol. 2747:
Radar Sensor Technology
Gerald S. Ustach, Editor(s)

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