Metrological use of Loran-C navigation receivers

The performance of accurate time and frequency measurements based on the Loran-C system using commercial navigation receivers is described. Techniques, criteria of choice, and suitability of commercial equipment, sources of errors, and experimental environment are discussed, and some results are compared with similar ones taken at IEN (Istituto Elettrotecnico Nazionale), the Italian national metrological laboratory. One of the two proposed methods does not require any alteration to the equipment, whereas with both of them continuous monitoring of all the transmitters of a chain is possible using a single receiver