Cross Chain Loran Monitor Planned for UNH
Radionavigation Systems Laboratory

With cooperation and support from Locus Inc. of Madison, Wisconsin Al Frost (Professor of EE Emeritus) is presently completing the installation of a state-of-the-art multi-chain digital Loran receiver in the ECE Department rooftop communications laboratory. During its past two sessions the US Congress has provided substantial support for a comprehensive up-grading of the national Loran system. Also plans in Europe are being advanced for the strengthening and revision of the present European Loran network to include the Russian version of Loran Chayka. A new modulation technique, Eurofix, now permits Loran stations in Germany, Norway and France to broadcast local differential corrections for GPS. While the utility of Loran as a stable terrestrial-based navigation aide is well known, it has only been in recent years that the use of these signals for information and data network synchronization and timing has been applied on a nation wide basis. The system improvements being carried out by the US Coast Guard including the final installation of modular solid state transmitters at all 27 existing sites, and the incorporation of high sensitivity multi chain control receivers has provided the infra structure necessary for total network synchronization with Universal Time to nanosecond precision.

The navigation and positioning community which includes General Aviation, recreational boating, the fishing industry, and vehicle management groups will no longer be limited to using only stations within a locally synchronized group. New computer based multi-tasking receivers can now combine and analyze signal information from any four stations in range. These groups or "chains" as they were originally called provide comprehensive nation-wide coverage. The Locus Satmate System being implemented at UNH permits the continuous monitoring and recording of status information from over half the CONUS Loran stations. Using multiple signal comparisons from several station configurations atmospheric noise and multi-path effects can be extracted and navigation data comparisons made with GPS. Satellite navigation has become a major facility, but needs local corrections and a redundant backup to cover intervals of signal or satellite outages due to natural or manmade interference and solar activity. Similar monitor setups are currently in operation in the Netherlands, Madison WI and Santa Barbara CA.

The renewal of Loran facilities is being carried out by the U.S. Coast Guard Loran Support Unit in Wildwood NJ. The Commanding Officer LCDR Alan Arsenault is a graduate of the US Coast Guard Academy and obtained his MS in EE at UNH in 1994 by presenting a thesis on the influence of auroral activity on the monitoring of Loran stations in Alaska. Dr. Frost was his thesis advisor.