Simulation of future GPS clock scenarios with two composite clocks

The performance of the GPS constellation is modeled using four possible ensembles of monitor site clocks and two different versions of the composite clock algorithm. The analysis of our previous paper is scrutinized; the conclusion remains that the improvements due to improved station clocks are minimal if the “Greenhall” algorithm is used for the composite clock. The response to a satellite and monitor station time step is investigated. Furthermore, the proportional process noise case is studied for different initial covariances.