A New Approach to Ionospheric Delay Corrections in Single Frequency GPS Receivers
INSTITUTO ELETTROTECNICO NAZIONALE GALILEO FERRARIS TORINO (ITALY)
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The IEN Time and Frequency Laboratory is equipped with single frequency GPS receivers to relate the Italian time scale to UTC and to give the traceability to the reference clocks of secondary laboratories. The synchronization data obtainable from the GPS system, in spite of its high performances, are affected by various error sources, one of the most important being the ionospheric corrections applied inside the receivers according to a model. To evaluate the influence of these corrections on the common-view synchronization results, some investigations have been performed at IEN, using measurement from an ionosonde to test some ionospheric models, and the data supplied by two dual-frequency GPS receivers located at or nearby time and frequency laboratories. For each geodetic receiver and satellite tracked, the differential hardware delay was computed using an original approach developed at IROE. The computed ionospheric delay corrections have subsequently been used to post-process a set of GPS common-view synchronization results between IEN-Italy and ROA-Spain and the uncertainty of the comparisons evaluated.
- Test Facilities, Equipment and Methods
- Navigation and Guidance
- Radio Communications