Integrity Risk Minimisation in RAIM Part 1: Optimal Detector Design

Abstract

This paper describes the first of a two-part research effort to find the optimal detector and estimator that minimise the integrity risk in Receiver Autonomous Integrity Monitoring (RAIM). In this first part, a new method is established to determine a piecewise linear approximation of the optimal detection region in parity space. The paper presents examples suggesting that the optimal detection boundary lays in between that obtained using chi-squared residual-based RAIM, and that provided by Solution Separation (SS) RAIM, as one varies the alert limit requirement. In addition, these examples indicate that for realistic navigation requirements, the SS RAIM method approaches the optimal detection region. The SS RAIM detection tests will be employed in the second part of this work, which focuses on the design of non-least-squares estimators to reduce the integrity risk in exchange for a slight increase in nominal positioning error. K E Y WO R D S 1. RAIM.2. Risk minimisation.

Exploiting Satellite Motion in ARAIM: Measurement Error Model Refinement Using Experimental Data

“…Nominal simulation parameters are defined in [2], and include:  a five degree satellite elevation mask  ARAIM CSC measurement error model parameters in equations (1) to (10), and (21)  navigation requirements: Fig. 8 (TB = 600s, TRB = 300s).…”

“…Integrity risk is the probability of undetected faults causing unacceptably large positioning errors. Multiple research efforts have recently been conducted to design optimal estimators and detectors that minimize the integrity risk in ARAIM, while meeting specified continuity and accuracy criteria [7][8][9][10]. These methods have been employed in the 'ARAIM Milestone 2 Report' [2] to identify the circumstances under which dualfrequency GPS/Galileo could satisfy LPV-200 requirements globally.…”

“…In addition, the alert limit (i.e., the limit on acceptable positioning errors, which defines hazardous situations) is 35 meters for LPV-200, which is much larger than, for example, the Category II precision approach alert limit requirement of 10 meters [11]. Thus, given that the methods used in [7][8][9][10] reach the best achievable performance, 'snapshot' ARAIM algorithms cannot provide global service better than LPV-200.…”

Impact quantification of satellite outages on air navigation continuity

“…In particular, the role transition from backup to primary means of navigation has increased the significance of H‐ARAIM continuity as compared to conventional RAIM. Most prior ARAIM work focused on reducing integrity risk [11–13]. Only few investigated continuity, and in most cases, false alarm (FA) was considered the only source of LOC [14, 15].…”

Integrity Risk Minimisation in RAIM Part 2: Optimal Estimator Design

“…This two-part research work describes the design, analysis and evaluation of new methods to determine the optimal detector and estimator, which minimize the integrity risk in RAIM. Part 1 focused on optimal detection methods (Joerger et al, 2015). Part 2 is presented in this paper, and addresses estimator design for integrity risk minimisation.…”