The Merlin Signal Generator - A Powerful, Low-Cost Constellation Galileo/GPS Signal Simulator

J. Winkel, R. Wolf, G. Prokoph, G. Mocker

Abstract:	With the upcoming Galileo System and the GPS Modernization program the need for a powerful signal simulator for the receiver developers has increased. In response to this need IfEN GmbH and Work GmbH launched a joint venture to develop a flexible signal generator, capable of simulating all currently planned civil Galileo signals as well as all civil signals specified for GPS III. Key drivers for the design were flexibility, scalability and low cost. The simulator consists of three sections: The steering software, which runs on a normal Windows or Linux based PC, the digital base-band part and three or four digital-to-analog up-converter sections. The steering computer is connected to the signal generation hardware by LAN and provides the base-band hardware with the steering data for each individual signal channel. The steering data consist of relative code offsets, Doppler shifts, power levels etc. The steering parameters are inferred from the configuration, i.e. the constellation, user trajectory and signal environment being simulated and the current system time. All simulation parameters are highly configurable. The software also provides the hardware with raw navigation data frames, including time-stamp. The base-band processor receives the data and constructs the base-band signal modulated with the data frames. Doppler and code offsets are also applied at this stage. The base-band signals for each frequency band are combined digitally and upconverted using one analog chain. This approach practically eliminates all relative group-delays within each band. The up-converter shifts the combined digital signal to the appropriate RF-frequency. Each up-converter can be configuredindependently to any RF-frequency in L-band and can service up to 8 satellites (Galileo and/or GPS).
Published in:	Proceedings of the 19th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2006) September 26 - 29, 2006 Fort Worth Convention Center Fort Worth, TX
Pages:	246 - 250
Cite this article:	Winkel, J., Wolf, R., Prokoph, G., Mocker, G., "The Merlin Signal Generator - A Powerful, Low-Cost Constellation Galileo/GPS Signal Simulator," Proceedings of the 19th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2006), Fort Worth, TX, September 2006, pp. 246-250.
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