Common-View LORAN-C as a Backup to GPS for Precise Time Recovery

摘要

The LORAN-C network is being recapitalized to serve as a backup to GPS for navigation and timing. LORAN-C is being investigated as a precision (sub 100 ns) time recovery system for use in the continental United States. Traditionally, LORAN-C time recovery has been limited by propagation effects (both spatial and temporal) to provide time recovery in the microsecond range. By employing common-view techniques long used in GPS, the potential exists to enhance time recovery performance by over an order of magnitude using LORAN-C. The LORAN-C Accuracy Panel (run by the US Coast Guard) has sponsored a research project to collect data and determine the performance level for time recovery using common-view LORAN-C. This paper presents the results of that work. This paper begins with a short overview of the LORAN-C recapitalization project, with an emphasis on timing enhancements at the transmitting stations. A description of the commonview LORAN-C test network follows. Data collected in Boulder will be corrected via commonview using a near field station and a far field station. Results will be analyzed to determine the dependence of time recovery precision on distance.