Validation of GNSS ARAIM Algorithm Using Real Data
This paper presents the research results on validation of the GNSS ARAIM (Advanced RAIM) algorithm, which is required in extending GNSS applications to areas demanding high integrity and safety, such as precision approach of LPV-200 phase before landing.
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Validation of GNSS ARAIM Algorithm Using Real Data Bin Li, Jizhang Sang and Yun Wu
Abstract This paper presents the research results on validation of the GNSS ARAIM (Advanced RAIM) algorithm, which is required in extending GNSS applications to areas demanding high integrity and safety, such as precision approach of LPV-200 phase before landing. In the ARAIM algorithm, the integrity risk of the GNSS systems is quantified by applying theory of multiple-hypothesis (MH). The multiple hypotheses are tested individually by using the method of solution separation (SS). Depending on different scenarios of the potential risks in the GNSS system, the given total tolerated integrity risk is allocated among the satellite-failure cases. For each case, the user’s XPL (including HPL, and VPL which is more concerned in this paper), accuracy and EMT, are predicted. In this paper, the ARAIM algorithm is studied using real GNSS observation data from a number of IGS stations at different locations, and then the availability levels of the GPS and GPS/GLONASS systems are evaluated based on the navigation performance requirements of LPV-200. Results show that: (1) VPE calculated using GNSS observation data are consistent with the results of the predicted VPL, accuracy and EMT, which validates the ARAIM algorithm. (2) Under the ARAIM, the highest availability achieved in the GPS system is only 63.04 %, while availability in the GPS/GLONASS system achieves more than 99.0 %, which fully meets the navigation performance requirements of LPV-200. Keywords Integrity ARAIM
LPV-200
Multiple hypothesis solution separation
B. Li (&) J. Sang Y. Wu School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China e-mail: [email protected]
J. Sun et al. (eds.), China Satellite Navigation Conference (CSNC) 2014 Proceedings: Volume II, Lecture Notes in Electrical Engineering 304, DOI: 10.1007/978-3-642-54743-0_18, Springer-Verlag Berlin Heidelberg 2014
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18.1 LPV-200 Requirements and GNSS Ranging Error Characteristics 18.1.1 LPV-200 Requirements Federal Aviation Administration (FAA) has claimed to provide LPV-200 capability worldwide without support of SBAS and Instrument Landing System (ILS) depending on GNSS during 2020–2025. Here, LPV-200 stands for Localizer Performance with Vertical guidance and indicates that decision height is 200 feet above ground level. According to International Civil Aviation Organization (ICAO), the performance requirements of LPV-200 are as follows [3]: • Probability of Hazardously Misleading Information (HMI) must not exceed 1 9 10-7/approach. • False Alert Probability must not exceed 4 9 10-6/15 s. • Vertical Alert Limit (VAL) equals 35 m. • Accuracy must not exceed 4 m, and Effective Monitoring Threshold (EMT) must not exceed 15 m.
18.1.2 GNSS Ranging Error Characteristics Two sets of parameters below are defined in ARAIM algorithm. One is for accuracy, the other for integrity. URE is the non-integrity-assured standard deviation of the range component of clock/ephemeris er
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