GPS/Wide Area Augmentation System (WAAS) Final Approach Error Analysis

Abstract

ABSTRACT: The total system error (TSE) and navigation system error (NSE) of the GPS/Wide Area Augmentation System (WAAS) are analyzed for the case of aircraft executing the final approach phase of flight. Error statistics and characteristics are presented for approach category C test flight data. NSE is shown to constitute only a small fraction of TSE and is found to have short- and long-term components of the same order of magnitude, with long-term components slightly larger. NSE data also displays a slightly larger vertical standard deviation than horizontal standard deviation, but TSE has a larger horizontal standard deviation than vertical standard deviation. No correlation is evident between the vertical and horizontal components of either NSE or TSE. The normal distribution model and the collision risk model are briefly considered for fits of the TSE and NSE probability distributions.