GNSS Constellation and Performance Simulator for Testing and Certification

P. Berglez, E. Wasle, J. Seybold, B. Hofmann-Wellenhof

Abstract:	The global navigation satellite system (GNSS) user receivers, especially mass market receivers, have to face demanding cost constraints. These constraints are not only related to the cost of the hardware itself, but also include development, production, testing, and certification expenses. One approach for saving expenditures in a receiver lifecycle is to use a simulation environment rather than performing cost- and time-intensive field testing and validation. Intensive and reproducible testing and validation are prerequisites for certification of GNSS receivers. It can be expected that most of the current receiver developments will pass through certification processes in the years to come. Within the certification process, three main components of the receiver have to be tested – the RF-front-end, the baseband processing and the position, velocity, and time software (PVT). For a successful certification, especially the PVT module has to fulfil certain requirements regarding performance and robustness. The best way of evaluation is the closed loop test, using a GNSS constellation and performance simulation tool as an input source. Comparing the user defined input parameters with the results of the PVT software provides valuable information about the performance and behaviour of the tested module. GNSS signal simulators provide an effective tool for simulating the behaviour of satellite-based navigation systems. They have to model the real world as close as possible, taking various effects and error sources into account. Since software-based receivers evolve rapidly, a strong need for a tool which enables testing and certifying the behaviour of the baseband, implemented in software, is needed. After a brief introduction on the overall concept, the paper mainly focuses on the certification and testing tasks and the architectural concept of the simulator. Afterwards the main components of the simulator, i.e. the GNSS constellation simulation, the computation of the ephemeris parameters used in the navigation message and the strategies for the simulation of propagation effects are discussed in more detail. At the end, some results of testing and validating a software-based receiver with the GNSS simulator are presented. Thereby main emphasis is placed on the propagation effects.
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	2220 - 2228
Cite this article:	Berglez, P., Wasle, E., Seybold, J., Hofmann-Wellenhof, B., "GNSS Constellation and Performance Simulator for Testing and Certification," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 2220-2228.
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