Assessment of ARAIM Availability in Brazilian Territory: Operational Evaluation for Civil Aviation

In this paper, an assessment of ARAIM availability in Brazilian territory is presented, together with an operational evaluation considering civil aviation requirements. Data from Global Navigation Satellite Systems (GNSS) receivers belonging to the Brazilian GNSS-NavAer network were used in order to provide protection level information calculated with RAIM and ARAIM algorithms. Eight different locations in Brazilian territory were considered for this assessment, chosen based on their distance to the magnetic equator. In this way, results from different geomagnetic latitudes could be compared. For each station, two months of data were analyzed: one month corresponding to the period of high ionospheric scintillation activity (September to March), one month corresponding to the period of low ionospheric scintillation activity (April to August). The following ARAIM modes were simulated: H-ARAIM GPS+GAL Ifree and V-ARAIM GPS+GAL Ifree. The RAIM GPS L1 mode were also simulated in order to compare the availability results for RNP(x) with those provided by the H-ARAIM GPS+GAL Ifree. Simulation results indicated that the HARAIM GPS+GAL Ifree mode is robust for RNP 0.1 and RNP 0.3 in Brazilian territory. Protection levels below 186 m were achieved in the considered scenario. VPL-250 operation was not achieved in Brazilian territory as a whole, only some stations presented availability ? 99% during a specific period of the day.