A CIRCULAR MEASUREMENT FOR LINEARLY POLARIZED GROUND PENETRATING RADAR TO MAP SUBSURFACE CROSSING CYLINDERS

Circular cylinders are important classes of environmental and engineering targets which act as depolarizing features, such as pipes, cables, rebar and tree roots. Two-dimensional plan survey using the linearly polarized Ground Penetrating Radar (GPR) is verified as an effective method to obtain the full-resolution image of subsurface objects and architecture. Compared to the regular measurement, a circular measurement using bow-tie antenna is proposed and shown its obvious advantage to map subsurface crossing cylinders with unknown orientations. The configuration of circular measurement is also an important index for obtaining a high-quality image; meanwhile, the proper spatial sampling interval can reduce the data acquisition time which is very important factor in field survey. A field measurement using 500MHz bow-tie antenna was carried out in the sandpit and validated the effectiveness and feasibility of the proposed circular measurement.