Estimation of three-dimensional coherent source positions with a directional borehole radar by MUSIC algorithm

A borehole radar is one form of ground penetrating radars, which operates in a borehole. The significant feature of a borehole radar is its accessibility to targets. Most conventional borehole radar use dipole antennas, which are omnidirectional. However, in many engineering applications, the three-dimensional positions of targets such as fractures and pipes should be accurately determined. We have designed and constructed a prototype broadband directional borehole radar system. The receiver is a conformal array antenna. This radar system operates between 100 and 300 MHz. Since the space available for the array and frequency bandwidth are limited, a super resolution technique should be applied. This paper presents a method for three-dimensional position estimation of coherent broadband sources with the conformal array in a borehole. This method is based on the MUSIC algorithm, and the problem formulation and a decorrelation algorithm are shown. Also, we show experimental results to verify the presented algorithm.