Furgo AtomiChron®
Warning
Users need a compatible L-band GNSS antenna to access the Fugro AtomiChron® service.
Fugro AtomiChron® is a global, real-time, precise clock synchronization and authentication service based on GNSS, for applications that require resilient, accurate and reliable time and frequency. This innovative technology eliminates time drift caused by clocks counting time at slightly different rates and gives users access to extreme frequency stability as well as extreme accurate time references, with levels that surpass high-calibre industrial standard caesium clocks and approaching hydrogen maser performance. Additionally, the service is disseminated through geostationary communication satellites with an over-the-air activation.
Fugro AtomiChron overview.
Specifications
- Timing accuracy: <5 ns UTC (95% of the time)
- Accuracy: <1 ns to Fugro AtomiChron® timescale (independent of world-wide location)
- Performance improvement: >10x better than existing high-end GNSS receivers
- Navigation Message Authentication (NMA) status: per satellite status for all 4 GNSS constellations concurrently
Subscription Sign-Up
The AtomiChron® subscriptions are managed by Fugro. To subscribe, Fugro will need to know the serial number of the mosaic-T module, which is listed on the sticker of the module. If this is worn out, there are other methods to determine this information; such as accessing the internal web server.
Serial Number listed on the mosaic-T module.
Fugro AtomiChron ID on the mosaic-T web page.
Spoofing
With the precise time service, the receiver computes a precise value (sub-nanosecond precision) of its clock bias with respect to the AtomiChron® time scale. The clock bias is reported in the PVTCartesian and PVTGeodetic SBF blocks, with the TimeSystem field set to Fugro AtomiChron. Clock biases computed using only satellites from individual constellations are reported in the FugroTimeOffset SBF block. A significant inter-constellation offset may hint at a spoofing attempt.
With the navigation-message authentication (NMA) service, the receiver detects satellites transmitting non-genuine navigation data, and excludes them from the position and time computation. The status of the AtomiChron® authentication is reported in the FugroAuthStatus SBF block. A global NMA-authenticity flag is available in the the RFStatus SBF block.
Clock Bias
Active Subscription
With an AtomiChron® subscription, the firmware will use Fugro's composite bias reported in FugroTimeOffset to discipline the internal/external oscillator's frequency. Users also have the option to select a clock bias of individual GNSS constellations over Fugro's composite bias.
Expired Subscription
Without an AtomiChron® subscription, the firmware will use the composite GNSS RxClkBias from PVTGeodetic to discipline the internal/external oscillator's frequency.
