A stepped frequency radar for use on Horizontal Directional Drills

Horizontal Directional Drills (HDDs) are used to install utilities underground. However, the use of drills in urban environments carries the risk of striking and damaging pre-existing utilities. This paper describes the development and testing of an SFCW radar designed to be installed on the HDD head to determine the presence of obstacles in or nearby the boring path. Transmit and receive antennas are mounted on the drill shaft, behind the drill head spade, and transmit both ahead and to the side of the drill head. Data can be collected at up to 50 traces per second, and all processing and display is done in real time. Special algorithms were developed to enhance the data, and aid in obstacle detection.