THE CONVENTIONAL ILS-SO WHAT'S NEW?

J. J. Battistelli

Peer Reviewed

Abstract:	With the emphasis the Microwave Landing System (MLS) is receiving in the literature, one must not lose sight of the fact that the Conventional Instrument Landing System (ILS) will be an operational system well into the 1980’s. The ILS is not only used for Category I and Category II landings and flight tests,but is now utilized for Category III Landing Feasibility Studies. The FAA, recognkng the increasingly stringent requirements being placed on the ILS, has been conducting research and development programs designed to yield significant improvements in ILS capability. This paper describes the results of some of these programs. The latest configurations for the localizer, glide-slope and their monitor are discussed as well as the effects of reflecting objects on or near the aerodrome and terrain. New localizer antenna arrays are being developed that limit the amount of stray radiation on the aerodrome and surrounding terrain. These new arrays yield improved course characteristics. Integral and wide aperture monitors have been developed that give a true analog of the signal in space. Glide-slope antenna arrays are being developed that do not utilize image effects. Therefore, they are not as susceptable to environmental effects. Optimized image-type arrays are under study to minimize the effects of shortened ground planes; and integral monitors have been developed to give increased monitoring reliability. Comprehensive programs to ascertain the effects of taxiing 747’s and 797’s on glide-slope and localizer signals are being accomplished. Modeling, ray-optics and classical electromagnetic techniques have been utilized for these studies and the major results are presented.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 21, Number 2
Pages:	170 - 183
Cite this article:	Battistelli, J. J., "THE CONVENTIONAL ILS-SO WHAT'S NEW?", NAVIGATION: Journal of The Institute of Navigation, Vol. 21, No. 2, Summer 1974, pp. 170-183.
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