Abstract: A method and apparatus for the remote detection of non-conductive pipes is described. The system consists of transmitter (Tx) and receiver (Rx) units. The transmitter unit induces mechanical vibrations into the pipe, and generates a reference signal which is relayed to the receiver. The receiver unit senses vibrations from the ground and converts the vibrations into an electrical signal, and receives the reference signal from the transmitter. Using synchronous detection, the receiver compares the reference signal to the received signal from the ground. The output of the receiver is proportional to the strength of the signal from the ground and therefore indicates the proximity of the receiver to the underground pipe.