Integrated GPS/Loran RF Simulator Development

Benjamin Peterson and Kenneth Dykstra

Abstract:	As part of the Federal Aviation Administration’s (FAA) Loran evaluation program, Peterson Integrated Geopositioning and CAST were tasked and have developed an integrated GPS/Loran RF simulator. The RF outputs of this simulator are precisely synchronized at the GPS pseudorange/Loran Time of Arrival (TOA) level to enable the testing of integrated receivers where the observables are combined at this level. The system works by the CAST simulator generating a scenario file of times and positions, this file is accessed by the Loran simulator and synchronization is accomplished by starting both simulators on a common edge corresponding to the scenario start and using a common reference oscillator. The Loran portion of the RF simulator produces either electric or dual channel magnetic field signals, and either standard Loran or modulated signals. This modulation includes absolute time messages and station identification that will enable tightly coupled integrated and master independent operation with no ambiguity. It also includes differential Loran messages and early skywave warnings for aviation users. Loran noise is a combination of Gaussian and impulse noise and is presently based on Technical Standard Order (TSO) C60B. Blink or off-air conditions are possible parts of the scenario. The chains are synchronized to enable multi-chain receiver operation and skywaves can be simulated as well. The GPS portion of the RF simulator generates GPS L1/L2 and WAAS signals corresponding to the scenario trajectory data. The GPS RF signals can include the effects of SV clock and ephemeris errors, atmospheric errors, and received signal multipath. The GPS and Loran simulators are connected by an Ethernet link for data exchange and time synchronization.
Published in:	Proceedings of the 60th Annual Meeting of The Institute of Navigation (2004) June 7 - 9, 2004 Dayton Marriott Hotel Dayton, OH
Pages:	455 - 461
Cite this article:	Peterson, Benjamin, Dykstra, Kenneth, "Integrated GPS/Loran RF Simulator Development," Proceedings of the 60th Annual Meeting of The Institute of Navigation (2004), Dayton, OH, June 2004, pp. 455-461.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In