Open AccessEvaluating the quality of WAAS availability control algorithm under geomagnetic storm conditions
Author(s) -
V. V. Demyanov,
Danila Khalimanov,
М. В. Федоров,
Olga Imarova
Publication year - 2020
Publication title -
informacionno-upravlâûŝie sistemy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.202
H-Index - 6
eISSN - 2541-8610
pISSN - 1684-8853
DOI - 10.31799/1684-8853-2020-2-46-59
Subject(s) - global positioning system , computer science , real time computing , range (aeronautics) , remote sensing , algorithm , simulation , engineering , telecommunications , geology , aerospace engineering
The Wide Area Augmentation System (WAAS) is vulnerable to false alarms about the violation of the required navigation parameter availability under geomagnetic disturbances. As a consequence, the system operation efficiency might decrease because of a mismatch between the output of the control system and the actual quality of the navigation-time support. Purpose: Comparative analysis of the actual quality of navigation-and-time support for GPS users and the output information of the system for monitoring the availability of the required WAAS navigation parameters under a moderate magnetic storm and with technical failures during the operation of separate segments of GPS and WAAS systems. Results: Location errors were calculated for 82 reference stations in the USA equipped with GPS navigation receivers. The calculations used the geometric ranges of visible navigation satellites and the corresponding real values of the ionospheric range-measurement error determined by the method of two-frequency measurements. Based on the same data and through the use of the conventional standard WAAS availability control algorithm, the user protection levels were calculated in the horizontal and vertical planes. The results of these calculations are presented as a time graph of WAAS operating area coverage percentage, which was compared with the respective graphs presented in the official WAAS work reports. It is established that there are cases of significant discrepancy between the forecasts about the availability of the required navigation parameters according to the WAAS data and the real quality of positioning in the operating area of this system. There are discrepancies in the results of calculations of protection levels in the horizontal and vertical planes obtained from official reports on the operation of the system and in calculations based on the geometric range and real ionospheric range-measurement error. Practical relevance: Recommendations are proposed in order to reconsider the development of a navigation parameter availability control for wide-area augmentation systems, splitting the calculation into “locally dependent” and “globally dependent” components of differential corrections of range-measurement errors. It will reduce the likelihood of false alarms or dangerous inconsistencies in information within the system.