ILS Localizer Alignment and Structure Model.

Nonstationary statistical analysis of flight inspection data for 13 Category II and Category II-training Localizer facilities is used to obtain statistical models for the Localizer alignment error and structure. Models for these two components of Localizer anomalies are given in terms of two linear differential equations and Gaussian probability density functions especially useful for landing system performance analysis. The structure component of the received Localizer guidance signal is found to be stationary, to have a standard deviation of 2.47 microamperes, and a characteristic length of 1309. ft. The alignment error component of the received Localizer guidance signal is found to have a mean of 2.25 microamperes probably due to the relatively small sample of different Localizer facilities, and a standard deviation of 4.92 microamperes.