1. A system to select one or more types of satellites from a plurality of types of satellites in a multi-constellation of satellites, the system comprising: a plurality of receivers including at least: a first receiver configured to input signals from a first type of satellite; and a second receiver configured to input signals from a second type of satellite; a processor configured to: execute a multi-constellation-selection software module to: associate a current position with a mapping feature, wherein mapping features include at least one of: a plurality of grid points (GP); a plurality of complex polygons (CP); and a plurality of combinations of complex polygons and grid points; select at least one selected type of satellite from the plurality of types of satellites based on the associated mapping feature; and execute a compute-position/velocity/time (PVT) software module in order to compute a current position/velocity/time based on at least one selected input signal input at a receiver associated with the at least one selected type of satellite; and feed the computed current position/velocity/time to the multi-constellation-selection software module based on the execution of the compute-PVT software module, wherein the system is configured to implement rules of operation for the at least one selected type of satellite.