Summary of RTCA SC-159 GPS Integrity Working Group Activities

Abstract

Working Group 5 of RTCA Special Committee (SC)-159 has spent the past several years working on the problem of GPS fault detection and exclusion (FDE) for a primary-means navigation system that can support oceanic en route through nonprecision approach modes of flight. The results of this working group's activities have been incorporated into RTCA/DO-229, Minimum Operational Performance Standards (MOPS) for GPSAVAAS Airborne Equipment, and will also serve as a baseline for the GPS/GLONASS and GPS/INS MOPS. The purpose of this paper is to provide a history of the development of the FDE requirements, algorithms, and test procedures, as well as a summary of the main issues addressed by the GPS Integrity (FDE) Working Group.

A measurement domain receiver autonomous integrity monitoring algorithm

“…The second threshold is the upper bound for the observed test statistic, which can be used to determine the so-called horizontal uncertainty level (HUL) (Lee et al 1996). The result is that two extreme thresholds are determined in the measurement domain, one from the probability of false alert and the other from the probability of missed detection and the alert limit, but only one test statistic, the square root of the sum of squared errors (SSE) is required.…”

GBAS testbed development in Taiwan with a prototype GPS/GBAS receiver

“…The RSMU is virtually a high performance GPS receiver, which has been precisely surveyed and served as a GPS reference station. The three-RSMU configuration is used due to the integrity consideration (Lee et al 1996, RTCA/SC-159 1998a, b, 2000. All the RSMUs transmit calculated DGPS corrections to the ground station.…”

Optimal Fault Detection and Exclusion Applied in GNSS Positioning

“…Conversely, swamping is when a good pseudorange is identified as faulty (Hekimoglu, 1997). This probability of identifying the wrong pseudorange is the probability of a wrong exclusion (Lee et al, 1996). In statistics this probability is referred to as a Type III error, where the null hypothesis is correctly rejected but the wrong pseudorange is identified as being faulty (Hawkins, 1980).…”

“…In statistics this probability is referred to as a Type III error, where the null hypothesis is correctly rejected but the wrong pseudorange is identified as being faulty (Hawkins, 1980). If the probability of a wrong exclusion can be evaluated, then there is a possibility that the position can be classified as available for navigation without even having to reapply fault detection (Lee et al, 1996). In the case where the probability of a wrong exclusion is too high, fault detection would still have to be reapplied after exclusion or the position would be classified as unavailable.…”