System for wireless communication along a drill string

摘要

A wireless communication and drill string telemetry system. The communication system is used for communicating information along a drill string between a boring tool and a boring machine. An insulator assembly provides an electrically insulated gap between the drill string communication path and a soil engaging electrode for the electrical return path. A transmitter assembly includes a data transmitter for encoding and transmitting a data signal. A signal coupler couples the data signal to the drill string and provides a controlled electrical connection between the drill string communication path and the soil engaging electrode. The signal coupler comprises a transformer and a current regulating circuit to adjust a voltage across the transformer's primary winding. A receiver assembly is disposed proximate the drilling machine and includes a toroidal pickup coil and a signal processing assembly. The pickup coil has an annulus and is positioned such that the drill string communication path passes through the annulus. The pickup coil produces a signal voltage in response to a signal current on the drill string that the signal processing assembly processes to extract the data signal.