GP path prediction method of the ILS glide path device

摘要

PROBLEM TO BE SOLVED: To provide a GP (Glide Path) path forecast method for a glide path apparatus for an ILS (Instrument Landing System) in a snowfall.;SOLUTION: The GP path forecast method comprises steps for: measuring the dielectric constant of the snowfall in constant snowfall depth or unequal snowfall depth by means of a resonance sensor serving as a dielectric constant measurement sensor; measuring each snow depth with snowfall depth meter; applying at least three-point reading to the data string of a mesh in the vertical direction of the constant snowfall depth or the unequal snowfall depth and data on the height of a GP antenna; repeatedly processing the following (1) to (5) using a distance from the GP antenna to a receiving point as variable: (1) presuming a reflecting point from the data string of the mesh; (2) obtaining a propagation path from the reflecting point, a GP antenna virtual image, and the receiving point; (3) obtaining the reflection coefficient of the snowfall; (4) obtaining a direct wave; and (5) obtaining the diffraction wave of a front geographic feature from data on the front geographic feature formed by the geographic feature located in front of a GP reflecting face. The input signal of an ILS receiver is obtained by adding the direct wave, the reflecting wave and the diffraction wave, having two frequencies, respectively. The reception instruction value DDM (Difference of Depth of Mod) of an on-board receiver is obtained.;COPYRIGHT: (C)2006,JPO&NCIPI