Design and Implementation of a Virtual Global Positioning System for Use in Distributed Interactive Simulations

Current military distributed virtual environments (DVEs) can not realistically allow systems to navigate using Global Positioning System (GPS) timing and position signals. Therefore, we designed and implemented the Virtual Global Positioning System Receiver (VGPSR) and added modules to the Solar System Modeler to enable GPS broadcast. The Solar System Modeler is a virtual environment application that portrays satellites in Earth orbit as well as planets, moons, asteroids, comets, and manmade satellites in deep space. We summarize the algorithms used to compute GPS satellite position and the current ephemeris. We describe the calculations the VGPSR performs to calculate position using the virtual GPS broadcasts. We present the accuracy and performance that the system achieves using the VGPSR and virtual GPS satellites in the SM. We suggest further research in the development of a virtual GPS for DVEs.