Study of RAIM algorithm and availability analysis under COMPASS

Integrity is often defined as the ability of the navigation system to provide timely warnings to the user when it is inadvisable to use the system for navigation. For aviation users, the integrity of the navigation system is essential. Receiver autonomous integrity monitoring (RAIM) is a mean of providing integrity with the capability of detecting when a satellite failure or a measurement error has occurred. The RAIM algorithm is contained within the receiver based on checking the solution consistency and requires redundant. This paper, firstly, discusses the satellite fault detection and identification methods of satellite failure. Secondly, the mathematical model to calculate protection levels is presented. Finally, the paper gives simulation results of RAIM available using Compass constellations.