1 Advanced Receiver Autonomous Integrity Monitoring (ARAIM) Schemes with GNSS Time Offsets

Within the current Advanced Receiver Integrity Monitoring (ARAIM) scheme, the time offsets between different Global Navigation Satellite System (GNSS) constellations are estimated along with a position solution and the GNSS receiver clock error. This scheme is so-called Time-offsets Estimated ARAIM, i.e., TOE ARAIM. In order to enhance the interoperability and compatibility between different constellations, the time offsets are expected to be broadcast to users in future multi-GNSS positioning and navigation applications. This paper describes two new ARAIM schemes to make use of the Broadcasted Time Offsets (BTOs): Time Offset Observed ARAIM (TOO ARAIM) and Time Offset Synchronized ARAIM (TOE ARAIM). It has been shown that the VPL performances of these two new ARAIM schemes rely strongly on the accuracy of BTOs. By varying the error model of BTOs, the simulation results have also demonstrated that the proposed new TOO ARAIM scheme can outperform the existing TOE ARAIM scheme- even if the accuracy of BTOs for integrity is degraded to 4.5m and the probability of a BTO fault is relaxed to . In addition, the new Time Offset Synchronized ARAIM scheme (TOS ARAIM) can also perform better than the existing TOE ARAIM scheme if the accuracy of BTOs for integrity can reach 0.75m. As the TOO ARAIM also has a very relaxed requirement on BTOs and better performance, the TOO ARAIM is regarded as a better ARAIM scheme for multi-GNSS with BTOs available