Development of a new algorithm for accurate estimation of GPR's wave propagation velocity by common-offset survey method

The development of a new algorithm to estimate electromagnetic (EM) wave propagation velocity (v) with shielded ground penetrating radar (GPR) antenna with high-frequency of 2 GHz is presented in this paper. Common offset method (fixed transmitter-receiver distance) is used for data collection, the antenna's separation distances and the corresponding triangulation geometry are also considered. The distribution of discrete velocities at each point oblique to the embedded target object is calculated by the proposed method. It is similar to the curve fitting process of hyperbolas in most software. The method has been validated in air and in concrete media and compared with the traditional hyperbola geometry method (ASTM D6432-11). The results show that errors of the new algorithm is significantly lower than the hyperbolic method. Besides, effects of analyzing reflected signals with different object depths are discussed. Based on the result, differentiation of velocity variations in concrete as a result of water seepage and leakage will be studied in next stage.