A Validated Solution for the Threat of Ionosphere Spatial Anomalies to Ground Based Augmentation System Users

• 발행기관: 한국항해항만학회
• 저자명: Sam Pullen Jiyun Lee Seebany Datta-Barua Young Shin Park Godwin Zhang Per Enge
• 간행물 정보: 『한국항해항만학회 학술대회논문집』2006년도 International Symposium on GPS/GNSS Vol.1, 1~6쪽, 전체 6쪽
• 주제분류: 공학 > 해양공학
• 파일형태: PDF
• 발행일자: 2006.10.24

영문 초록

This paper develops a complete methodology for the mitigation of ionosphere spatial anomalies by GBAS systems fielded in the Conterminous U.S. (CONUS). It defines an ionosphere anomaly threat model based on validated observations of unusual ionosphere events in CONUS impacting GBAS sites in the form of a linear “wave front” of constant slope and velocity. It then develops a simulation-based methodology for selecting the worst-case ionosphere wave front impact impacting two satellites simultaneously for a given GBAS site and satellite geometry, taking into account the mitigating effects of code-carrier divergence monitoring within the GBAS ground station. The resulting maximum ionosphere error in vertical position (MIEV) is calculated and compared to a unique vertical alert limit, or VALH2,I, that applies to the special situation of worst-case ionosphere gradients. If MIEV exceeds VALH2,I for one or more otherwise-usable subset geometries (i.e., geometries for which the “nominal” vertical protection level, or VPLH0, is less than the “normal” VAL), the broadcast σpr_gnd and/or σvig must be increased such that all such potentially-threatening geometries have VPLH0 > VAL and thus become unavailable. In addition to surveying all aspects of the methods used to generate the required σpr_gnd and σvig inflation factors for CONUS GBAS sites, related methods for deriving similar results for GBAS sites outside CONUS are suggested.

목차

1. Introduction

2. CONUS Ionosphere Anomaly Threat Model

3. Simulation of Worst-Case GBAS User Errors

4. Variations for Regions outside CONUS

키워드

GBAS Integrity Ionosphere Threat Model Protection Level Alert Limit