Graeme_77 Posted January 8, 2022 Report Share Posted January 8, 2022 (edited) The Challenger 650 has a comprehensive GPS/GNSS simulation, as well as fully realised Inertial Reference Systems. Some interesting behaviour can be seen. The avionics will need to retrieve the GPS almanac on first start, just like the real thing, except the simulation grabs it over the internet (at a realistic data rate) rather than using the satellite antenna. When you first load the jet, it may take some time to get a GPS fix. Remember getting a brand new SatNav (remember those?!) out the box and having to wait 20 mins until it could find itself, well now you know it was downloading the GPS almanac, just like the Challenger. When the avionics have a GPS position, they may indicate GNSS ONLY. This is because the Inertial Reference Systems take some time to align. Longer at higher latitudes, up to about 18 minutes if you try starting at CFS Alert. Less time on the equator. The IRSs need to "feel" the motion of the world turning beneath them to find true north and establish position, and the world moves more linear distance in the same time at the equator compared with the poles. As the IRSs are not available for navigation at this time, you may see a GNSS ONLY message on the CDU. This will clear when the IRSs align fully. You can even see the time to align by displaying the IRS STATUS on the MFD. Use MFD DATA, then DSPL MENU buttons on the CDU to choose the display page. Once the IRS have aligned, you're good to go. Edited January 8, 2022 by Graeme_77 3 Quote Link to comment Share on other sites More sharing options...
Huang JL Posted January 8, 2022 Report Share Posted January 8, 2022 GNSS NOT AVAILABLE How to solve Quote Link to comment Share on other sites More sharing options...
Graeme_77 Posted January 8, 2022 Author Report Share Posted January 8, 2022 The same answer as the other time you posted this question. You may be encountering a regional limitation such that you are not able to access the GPS almanac data. Government firewalls are something Hot Start and X-Aviation have little control over, but if a solution is possible the developers will find it. The CL650 can be used without GNSS functional, as the IRS and radio updating system is operational - you will have other limitations though. 1 Quote Link to comment Share on other sites More sharing options...
leha74ru Posted January 13, 2022 Report Share Posted January 13, 2022 On 1/8/2022 at 4:16 PM, Huang JL said: GNSS NOT AVAILABLE How to solve Quote Link to comment Share on other sites More sharing options...
richjb Posted March 4, 2022 Report Share Posted March 4, 2022 So I have a question... Did HS CL650 implement the 1 leap second GPS almanac bug???? That would be the height of realism! Thanks, Rich Quote Link to comment Share on other sites More sharing options...
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