Proceedings Article | 6 August 2009
Proc. SPIE. 7502, Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2009
KEYWORDS: Target detection, Radar, Metals, Dielectrics, Reflectivity, Profiling, Antennas, Signal generators, Ground penetrating radar, General packet radio service
The paper describes stepped frequency continuous wave (SFCW) ground penetrating radar (GPR), where signal's
frequency is discretely increased in N linear steps, each separated by a fixed ▵f increment from the previous one. SFCW radar determines distance from phase shift in a reflected signal, by constructing synthetic range profile in spatial time
domain using the IFFT. Each quadrature sample is termed a range bin, as it represents the signal from a range window
of length cτ/2, where τ is duration of single frequency segment. IFFT of those data samples resolves the range bin in into fine range bins of c/2N▵f width, thus creating the synthetic range profile in a GPR - a time domain approximation of the frequency response of a combination of the medium through which electromagnetic waves propagates (soil) and
any targets or dielectric interfaces (water, air, other types of soil) present in the beam width of the radar. In the paper,
certain practical measurements done by a monostatic SFCW GPR were presented. Due to complex nature of signal
source, E5062A VNA made by Agilent was used as a signal generator, allowing number of frequency steps N to go as
high as 1601, with generated frequency ranging from 300kHz to 3 GHz.
