Abstract: A surface guidance system for guiding aircraft equipped with Instrument Landing Systems along taxiways which utilizes two inductive loops (14,16) installed around the right half and the left half of the taxiways. Audio amplifiers (18,20) drive one loop (14) with an 90 Hz signal and the other loop (16) at 150 Hz. A sensor (22) mounted on the aircraft detects the composite magnetic field induced by the surface loops (14,16). The detected signal is conditioned and supplied to the ILS system to provide left/right lateral guidance to the pilot. Longitudinal aircraft position is determined by using dipole marker antennas (52) embedded near the taxiway center line. Each marker antenna (52) has a unique code identifier. Existing ILS equipped aircraft can sense the marker signal and transmit the aircraft position to the ATC facility. Additional pairs of loops (14,16) and marker antennas (52) are used for different taxiway or runway sections.