LAUSR

Subsurface pipeline detection and localization is an important problem in gas and oil transport as well as in construction and excavation missions. A 3D subsurface multistatic imaging radar with a novel focusing algorithm for pipelines is demonstrated in this paper. The traditional back-projection algorithm, which is suitable for discrete scatterers, cannot be used for extended scatterers such as pipelines whose scattering phase centers are dependent on the relative positions of the transmitter and receiver. To circumvent this problem, a new imaging algorithm that tracks the scattering phase centers in a way that is specific to pipelines is presented and shown to provide significantly better imaging performance. An analytical solution for pipeline scattering is used to derive the algorithm and justifications for the simplifying assumptions made is provided. The algorithm is tested by applying it to realistic lossy sand simulations data as well as experimental measurements data obtained by a portable vector network analyzer (VNA). Both simulation and measurement results demonstrate the ability of the algorithm to detect and localize metallic as well as dielectric pipes.