| Instrument Landing System (ILS) is the accepted worldwide system for providing approach guidance to aircraft. ILS has the disadvantage that the ground based antenna arrays are quite large and thus cannot be readily deployed for certain military tactical or civilian emergency scenarios. This paper presents a novel technique for utilizing compact and deployable ground equipment to provide an approach guidance capability similar to that of ILS. This technique is based on the use of unmodified airborne equipment already installed in all military and civilian aircraft of interest, a readily available Secondary Surveillance Radar Antenna on the ground, and relies on Image Theory to generate the Glide Slope component of ILS. Presented are the results of the theoretical modeling, computer simulation, and a set of actual field tests that were performed at Sierra Nevada Corporation, Sparks, Nevada in April and May of 1997. |
