ABSTRACT:The GNSS environment is experiencing two major changes: the introduction of a new civil signal in the L5 band and the launch of new GNSS constellations. These improvements could enable worldwide vertical guidance using Advanced Receiver Autonomous Integrity Monitoring (ARAIM). Before ARAIM can be implemented, it will be necessary to develop a common understanding across service providers of the navigation requirements, the threat model, the airborne algorithm, and the role of ground monitoring. We outline a concept for the provision of integrity based on ARAIM. First, an interpretation of vertical guidance (LPV-200) requirements is proposed. Then, we describe a comprehensive threat model for GNSS which includes both nominal performance and faulted behavior. We will show how the threats could be mitigated through the use of ground monitoring and the Integrity Support Message in addition to the ARAIM airborne algorithm. Finally, examples of constellation configurations providing worldwide coverage of LPV-200 are presented.

This paper presents a User Range Accuracy (URA)/Signal‐in‐Space Accuracy (SISA) analysis to support ARAIM based on a time‐dependent statistical characterization of orbit and clock error observations. By comparing precise orbits to broadcast ephemeris for each individual GPS and Galileo satellite, this work computes the Signal‐in‐Space Range Error (SISRE) that needs to be overbounded by the URA/SISA value included in the Integrity Support Message (ISM). Service data from January 2008 to February 2015 for GPS and from March to June 2015 for Galileo are processed, showing that range error is mainly driven by satellite's clock performance. In order for the ISM generation to account for the variation in error biases and standard deviation, GPS service history is broken down into monthly, quarterly, and yearly datasets. Results reveal that orbit and clock error distributions are non‐zero mean on a monthly basis, although biases tend to reduce as sample set size increases. Copyright © 2017 Institute of Navigation.

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