Timing via the New LORAN-C System

In 1999, the United States Federal Radionavigation Plan extended the life of the U.S. LORAN-C system while the long term benefits as a GPS backup are investigated. Since 1999, U.S. Congress has continued to provide funds via the Federal Aviation Administration (FAA) to develop and recapitalize the LORAN-C infrastructure. As a result of this recapitalization, the timing systems at the LORAN-C transmitting stations are being upgraded from its 1960's technology. This paper re-introduces LORAN-C with an emphasis on the improvements that are being provided to the LORAN-C user community and the timing performance and applications of the new system. These improvements include new timing systems, new transmitters and new user equipment. The paper begins with an introduction to the LORAN-C Recapitalization Project (LRP). Next a comparison of the technology and performance of the new LORAN-C system and the existing systems is presented with an emphasis on timing performance. The new time and frequency equipment (TFE) suite is presented with details on the local timescale computation, UTC recovery, and transmitter timing adjustment loop. Performance of the new system will be presented from the factory acceptance testing and field trials. Additional details will be presented on the timing performance of the new transmitter. The paper concludes with a summary of the ongoing efforts and results from the LORAN-C Accuracy Panel.