Ground based SAR imaging tool for the design of buried mine detectors

摘要

The detection of mines buried in the soil or covered by vegetation has become a topic of major importance. For this purpose, we propose to use electromagnetic waves in the UHF (ultra high frequency) range that have the ability to penetrate the soil or the vegetation. This technique is now well known as GPR (ground penetrating radar). Our contribution to the improvement of GPR is to use a synthetic aperture antenna in order to achieve azimuth (or cross-range) resolution. In 'stand-off' detection, the large antenna footprint would give a very bad resolution to a classical GPR. With a synthetic aperture antenna, it is expected that a low frequency GPR can deliver fine images of soil surfaces as well as subsurfaces. Furthermore, at low incidence angles, surface soil clutter level is very low. This is why, in order to help to design such future radar, an imaging tool has been developed at ONERA/CERT at the microwave laboratory. It is thus possible to study the detection of buried targets in various conditions of soils, humidity etc. The system versatility allows testing of the influence of the frequency bandwidth, the looking angle, the polarisation of the waves as well as to evaluate signal processing algorithms.