Localizability Analysis for GPS/Galileo Receiver Autonomous Integrity Monitoring

Abstract

With the European Commission (EC) and European Space Agency's (ESA) plans to develop a new satellite navigation system, Galileo and the modernisation of GPS well underway the integrity of such systems is as much, if not more, of a concern as ever. Receiver Autonomous Integrity Monitoring (RAIM) refers to the integrity monitoring of the GPS/Galileo navigation signals autonomously performed by the receiver independent of any external reference systems, apart from the navigation signals themselves. Quality measures need to be used to evaluate the RAIM performance at different locations and under various navigation modes, such as GPS only and GPS/Galileo integration, etc. The quality measures should include both the reliability and localizability measures. Reliability is used to assess the capability of GPS/ Galileo receivers to detect the outliers while localizability is used to determine the capability of GPS/Galileo receivers to correctly identify the detected outlier from the measurements processed.Within this paper, the fundamental equations required for effective outlier detection and identification algorithms are described together with the measures of reliability and localizability. Detailed simulations and analyses have been performed to assess the performances of GPS only and integrated GPS/Galileo navigation solutions with respect to reliability and localizability. Simulation results show that, in comparison with the GPS-only solution, the localizability of the integrated GPS/Galileo solution can be improved by up to 270%. The results also indicate an expectation of a considerable increase in the sensitivity to outliers and accuracy of their estimation with the augmentation of the Galileo system with the existing GPS system. K E Y

Emerging New Trends in Hybrid Vehicle Localization Systems

“…Integrity is defined as a measure of the trust which can be placed in the correctness of the information supplied by the total system; integrity includes the ability of a system to provide timely and valid measurements to users ESA (n.d.). Three key components have been proposed for integrity monitoring: 1) fault detection, 2) fault isolation, and 3) removal of faulty measurement sources from the estimates Hewitson et al (2004). The European Geostationary Navigation Overlay Service (EGNOS) and the Wide Area Augmentation System (WAAS), Hewitson (2003), are developed to form a redundant source of information for the Global Navigation Satellite Systems (GNSS) in order to perform integrity monitoring by providing correction information.…”

Distributional theory for the DIA method

“…For its generalization to recursive quality control in dynamic systems, see Teunissen and Salzmann (1989), Teunissen (1990). The DIA method has found its use in a wide range of applications, for example, for the quality control of geodetic networks (DGCC 1982), for geophysical and structural deformation analyses (Van Mierlo 1980;Kok 1982), for different GPS applications (Van der Marel and Kosters 1990;Teunissen 1998b;Tiberius 1998;Hewitson et al 2004;Perfetti 2006;Drevelle and Bonnifait 2011;Fan et al 2011) and for various configurations of integrated navigation systems (Teunissen 1989;Salzmann 1993;Gillissen and Elema 1996).…”

Optimal Fault Detection and Exclusion Applied in GNSS Positioning

“…Using the results of these studies Li (1986) then defined the Minimal Separable Bias (MSB) as the smallest bias that can be confidently identified for a set Type III error. Applying the MSB to the field of navigation, the separability of various satellite constellations has been analysed by Hewitson et al (2004), and Hewitson and Wang (2006).…”