GPS High Fidelity System Simulator – A Tool to Benefit Both the Control and User Segments

Ted Driver

Abstract:	With the advent of GPS Block IIR vehicles on-orbit, and GPS modernization on the horizon, the need for training within the control segment has increased. To meet this need, the High Fidelity System Simulator (HFSS) is being developed by Lockheed Martin Mission Systems. The HFSS will provide high fidelity simulations of an entire GPS constellation, including up to 30 Block II/IIA and Block IIR satellites as well as 20 monitor stations, 14 of which are NIMA stations. The simulator will provide full command and response capabilities, interactive models, full environment simulation, and selected payload simulation. This paper will meet two objectives: to describe the simulator in detail, defining the levels of fidelity for each of the major subsystems modeled, and, secondly, to discuss the benefits the simulator will provide to the 2 nd Space Operations Squadron (2SOPS) as a training and analysis tool serving both the Control and User segments. The simulator’s models are developed using object-oriented methodologies, allowing consistent interaction between models and easy expansion to new models and vehicle types. The simulator is intended to be a constellation on the ground, for use by 2SOPS to allow training so realistic, they won’t be able to tell the simulated from the real constellation. Anomaly insertion capabilities allow the training instructor to create scenarios the trainee may rarely see in live operations. The ease with which the simulator can be initialized with different sets of data will make it an indispensable analysis tool for 2SOPS operations. Scenarios can be played out on the ground with full realism, leading to new problem solutions and innovative techniques in a short amount of time. Such simulations will lead to increased accuracy available in shorter time frames for the user community. The simulator fully simulates Selective Availability (SA), allowing training and analysis to occur prior to implementation of the Presidential Decision Directive to turn off SA. In all, the simulator will provide an unparalleled opportunity for training and analysis on the world’s most sophisticated navigation system, allowing greater insight for the Control Segment benefiting both military and civilian users.
Published in:	Proceedings of the 54th Annual Meeting of The Institute of Navigation (1998) June 1 - 3, 1998 The Adams Mark Hotel Denver, CO
Pages:	507 - 515
Cite this article:	Driver, Ted, "GPS High Fidelity System Simulator – A Tool to Benefit Both the Control and User Segments," Proceedings of the 54th Annual Meeting of The Institute of Navigation (1998), Denver, CO, June 1998, pp. 507-515.
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