FUSION OF TWO ELECTROMAGNETIC FIELD SENSOR TECHNOLOGIES FOR APPLICATION TO THE LOCATION OF BURIED GAS PIPES. ANNUAL REPORT NO. 1, JULY 1, 1994-JUNE 30, 1995

This report describes work accomplished in the first year of a project to develop a practical pipe locator tool for both plastic and metal pipe. Efforts in the first year focused on showing separately the feasibility of both the GPR and Eddy current (EC) technologies to locate pipes. The ground penetrating radar (GPR) used for demonstration of feasibility was an FM-CW radar system operating the VHF and UHF ranges. In moderate-loss soils, images were produced on 4-inch (10 cm) polyethylene (PE) pipe down to 3 feet (.9 m); 2-inch (5 cm) PE pipe could be damaged to 2 feet (.6 m). With the EG technology, the edges of backfilled pipe trenches are detectable, and plastic pipes could be detected at shallow depths in high conductivity soils.