A sonde device can be added to a push camera system, CCTV platform or a separate device to allow tracking of the horizontal location and approximate depth of an existing pipe. A walk-over tracking system is used in conjunction with the sonde. The transmitter or sonde moves along the pipe. The transmitter emits a continuous magnetic signal, which is picked up by a portable hand-held receiver. Data transmitted to the receiver allows determination of the horizontal position of the pipe (based on maximum signal strength) and depth (based on the difference in signal strength between two vertically spaced receiving coils in the walk-over receiver.