Precise time dissemination using the INMARSAT Geostationary Overlay

INMARST has designed a Global Positioning System (GPS) (L1) transponder that will be included in their third-generation satellites. This transponder will broadcast a pseudo-GPS signal that can be used for navigation and also for disseminating integrity data and/or differential corrections for the GPS satellites. This INMARSAT Geostationary Overlay (IGO) service will be used to enhance the performance of the GPS navigation service for civil aviation and other users. The IGO service can also be used as a method of disseminating a precise time reference. Since the IGO signal is compatible with GPS, conventional GPS timing receivers can easily be modified to use the proposed service. Preliminary test results taken through the IGO satellite have demonstrated a timing accuracy of 10 ns.<
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