Modeling and Simulation of GPS Using Software
Signal Generation and Digital signal Reconstruction
Alison Brown, Neil Gerein, and Keith Taylor, NAVSYS Corporation
BIOGRAPHY
Alison Brown is the President and CEO of NAVSYS Corp. She has a PhD in Mechanics, Aerospace, and Nuclear Engineering from UCLA, an MS in Aeronautics and Astronautics from MIT, and an MA in Engineering from Cambridge Univ. In 1986 she founded NAVSYS.Currently she is a member of the GPS-III Independent Review Team and Science Advisory Board for the USAF and serves on the GPS World editorial advisory board.
Keith Taylor is a Project Manager for NAVSYS Corporation. He is responsible for developing MATLAB based GPS signal simulation tools for user selectable signal environments and jamming scenarios. He holds an MSEE from University of Florida and a BSEE from the University of Louisville.
Neil Gerein is a Project Manager for NAVSYS Corporation. He is responsible for a rapid acquisition FFT based GPS receiver system (COGNAC) and has developed firmware for Xilinx FPGAs and Altera CPLDs.He is currently completing his M.Sc. in Electrical Engineering and holds a BSEE in Electrical Engineering from the University of Saskatchewan.
ABSTRACT
GPS satellite simulator test facilities are used to checkout the software and hardware of GPS receivers and their augmentation systems. In general, they include satellite signal simulators, differential augmentation simulators and interface emulators. All testing is run in real time and requires considerable hardware and human assets. Initially, the dynamic scenario to be simulated must be designed and stored in the simulator control computer. This scenario specifies all relevant factors including the trajectory of the GPS receiver(s), the satellite constellation, the signal power and waveforms, environmental factors including propagation errors, and jamming effects. In general, there is considerable equipment setup and calibrations that must be performed prior to actually exercising the scenario. In addition, the satellite simulator and control equipment are expensive resources typically costing on the order of one million dollars.