Trenchless underground boring system with boring tool location

Abstract

An apparatus and method for locating an underground boring tool using a radar-like probe and detection technique. A boring tool is provided with a device which generates a specific signature signal in response to a probe signal transmitted from above the ground. Cooperative operation between the probe signal transmitter at ground level and a signature signal generator disposed within the boring tool provides for the accurate locating of the boring tool, despite the presence of a large background signal. The signature signal produced by the boring tool may be generated either passively or actively, and in a manner which differs from the probe signal in one or more ways, including timing, frequency content, or polarization. A survey of a boring site, made either prior to or during the boring operation, provides data related to the characteristics of the ground medium subjected to the survey and the identification of underground hazards, such as buried utilities. Knowledge of ground characteristics enables estimates of boring productivity and cost to be made. Accurate surveys of planned boring pathways can be made and compared, either contemporaneously or subsequently, against the accurately measured position of the boring tool during a boring operation. The direction of the boring tool may be adjusted in response to the measured position in order to maintain the boring tool along the planned pathway and at an optimum boring rate.