Title :
ILS glidescope evaluation of imperfect terrain
Author :
Poulose, M.M. ; Mahapatra, P.R.
Author_Institution :
Nat. Airports Authority of India, Bangalore, India
fDate :
3/1/1988 12:00:00 AM
Abstract :
Instrument landing systems (ILS) are normally designed assuming the site around them to be flat. Uneven terrain results in undulations in the glidescope. In recent years, models have been evolved for predicting such aberrations as a simpler alternative to experimental methods. Such modeling normally assumes the ground to be fully conducting. A method is presented for considering imperfect terrain conductivity within the framework of the uniform theory of diffraction (UTD). A single impedance wedge formulation is developed to a form that resembles the standard form of UTD, with only one extra term in the diffraction coefficient. This extends the applicability of the standard UTD formulation and software packages to the case of the imperfectly conducting terrain. The method has been applied to a real airport site in India and improved agreement with measured glidescope parameters is demonstrated
Keywords :
aerospace computing; aircraft instrumentation; electromagnetic wave diffraction; ground support systems; software packages; ILS glidescope; India; aircraft instrumentation; airport; ground support systems; impedance wedge; imperfect terrain conductivity; software packages; undulations; uneven terrain; uniform theory of diffraction; Aerospace electronics; Aircraft; Airports; Conductivity; Instruments; Optical computing; Physical optics; Physical theory of diffraction; Physics computing; Predictive models;
Journal_Title :
Aerospace and Electronic Systems, IEEE Transactions on