Advanced GPS Simulator/Receiver Prototyping System

S. Ganguly, A. Brown, M. Kirchner, M. Nguyen, P.F. Schnick, S. Green

Abstract:	This paper presents the architecture of an advanced testing system for performance evaluation of new GPS signals. The testing system consists of a software segment that generates and tracks GPS signals and a hardware segment which records live GPS signals and plays them back in real-time at the GPS frequencies. The software consists of a scenario generation module that simultaneously generates the signal dynamics for multiple satellites, a signal generator that produces a corresponding digital GPS IF, and receiver components to track and navigate using a GPS signal digitized at IF. The hardware captures GPS RF from either a live satellite broadcast or a signal generator, and records it at a suitable IF. It can also generate GPS RF from an IF recording. For example, the hardware and software can work together providing the generation of GPS RF from a software created IF file and software receiver processing of a recorded, live GPS signal. The scenario generation module calculates code and carrier phases as seen at a receiver, and also specifies relative signal levels between different satellites and between different codes of the same satellite. The relative signal level data allows simulation of the different propagation losses experienced with GPS signals, such as fading effects and shadowing and signal obscuration. The software signal simulator provides the means for easily adding external signal sources such as jammers and multipath. It also allows the simulation of multiple antenna scenarios for beamforming and other spatial processing techniques. This approach allows generation of complex scenarios in doctrinally correct fashion, starting from first principle. These involve complex jammers, receiver and jammer dynamics, physically tractable multipath, ionospheric and plasma effects, obscuration etc. The technique has been used for various high fidelity signal generations and testing schemes involving C/A, P and AES generated M-code. This allows rapid prototyping and test for current and future navigational systems under realistic conditions.
Published in:	Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003) September 9 - 12, 2003 Oregon Convention Center Portland, OR
Pages:	1107 - 1118
Cite this article:	Ganguly, S., Brown, A., Kirchner, M., Nguyen, M., Schnick, P.F., Green, S., "Advanced GPS Simulator/Receiver Prototyping System," Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003), Portland, OR, September 2003, pp. 1107-1118.
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