With the new upcoming GNSS constellation in the future it
might no longer be possible to use all satellites in view for
navigation due to limited tracking channels. This is in particular
true in the context of Advanced Receiver Autonomous
Integrity Monitoring (ARAIM), where the use of dual frequency
is favorable to mitigate ionospheric disturbances.
To address the issues of limited channels we propose two
different satellites selection strategies adapted for Horizontal
ARAIM in this paper. First a bare geometric approach
which comes with almost no additional computation effort
at the cost of less stable results. And second a heuristic
optimization which improves selection results significantly
while adding additional computational effort.
Both approaches are compared to brute force selected best
sets in terms of resulting protection levels, computational
cost and achieved ARAIM availability.
Results show the general applicability of both presented
selection methods in Horizontal ARAIM. Using limited sets
instead of all satellites in view can still provide global availability.
Depending on the method more or less satellites are
necessary to ensure sufficiently small and stable protection
levels