WAAS messages via LORAN Data Communications-Technical progress towards going operational

Ben Peterson, Ken Dykstra, Peter Swaszek, James M. Boyer, Kevin M. Carroll, Paul R. Johannessen, and Mitchell Narins

Abstract:	The LORAN data communications project, an important segment of the Federal Aviation Administration’s overall evaluation of LORAN to determine whether it can provide benefit to aviation, is intended to demonstrate that LORAN is capable of transmitting the entire Wide Area Augmentation System (WAAS)/Satellite Based Augmentation System (SBAS) corrections at the required 250-bit per second rate. The results of the overall evaluation being conducted by a government/academia/industry team will help support a future government decision regarding whether to continue LORAN services. In 2001, the LORAN data communications project focused on a proof of concept and through a number of static and flight tests, both in the continental US and Alaska, demonstrated that the 100 kHz LORAN signal could indeed be modulated at a high enough data rate using Intrapulse Frequency Modulation (IFM) to reliably transmit the full 250-bit WAAS message every second at extreme distances. The signals were, in fact, successfully demodulated at ranges sufficient to show that the LORAN system could potentially provide backup WAAS coverage over the entire continental US and all of Alaska. To date, this effort has used fairly limited duration transmissions on tube transmitters – nominally eight hours per day on a few sequential days. While some data was collected to show that the Coast Guard’s LOCUS® monitor receivers could successfully track the modulated signal, only one LORAN station was modulated at any one time and no tests were done navigating using the modulated signal. Efforts over the next few months will focus on several tasks that need to be completed to support a future operational decision. In this paper, we discuss modulation of existing solid-state LORAN transmitters and the establishment of a low power, short baseline test bed. The test bed will enable more extensive testing of LORAN navigation and communications in an environment with multiple modulated signals to better assess its capabilities and any affects on both legacy and new all-in-view receivers.
Published in:	Proceedings of the 2002 National Technical Meeting of The Institute of Navigation January 28 - 30, 2002 The Catamaran Resort Hotel San Diego, CA
Pages:	138 - 145
Cite this article:	Peterson, Ben, Dykstra, Ken, Swaszek, Peter, Boyer, James M., Carroll, Kevin M., Johannessen, Paul R., Narins, Mitchell, "WAAS messages via LORAN Data Communications-Technical progress towards going operational," Proceedings of the 2002 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2002, pp. 138-145.
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