Experience at the CENAM With Time and Frequency Standards Signals Received by the Global Positioning System (GPS)

摘要

The Time and Frequency Division of the Centro Nacional de Metrologia (CENAM) in Mexico has been working along two years with two high-stability signals reception systems: GPS and LORAN-C. We have determined the frequency stability of these systems using a cesium standard as the national reference. In Mexico this kind of research had not been done until now. In this paper a general review about advantages and disadvantages of different frequency and time dissemination systems is given. Then we expose the results of experimental research on frequency stability of GPS and LORAN-C for an averaging time of from 1 s to 1 day for different observation days. Finally we present the results of experimental research on electromagnetic interference around GPS receiver antenna, delay, and attenuation introduced by the transmission line. A time difference measurement system developed by staff of CENAM at the National Research Council (NRC) in Canada is used in order to calculate the frequency stability. Time domain measurements to calculate frequency stability for GPS and LORAN-C systems are employed.