GPS Ephemeris Message Broadcast Simulation.

摘要

The warfighter constantly needs increased accuracy from GPS and a means to increasing this accuracy to the decimeter level is a broadcast ephemeris message containing GPS satellite orbit and clock corrections. The ephemeris message is produced at the GPS MCS (Master Control Station) which receives GPS signal data from NGA and Air Force worldwide and uses sophisticated software to produce the orbit and clock corrections. The problem is getting the ephemeris message to the tactical user in a forward operating area. This thesis proposed a notional architecture for pushing the ephemeris message to the tactical user. It then modeled the architecture and simulated the broadcast of the ephemeris message to a tactical user using NETWARS. The baseline architecture was simulated and analyzed and then additional constraints were placed upon the network to simulate a real-world model. The simulation results demonstrated that the architecture was feasible for ephemeris message broadcast with the constraints on time intervals between broadcasts, residual traffic and message size.