GPS Satellites

[Phantom Raider]

I'm not sure if you have covered this or not, but I was wondering about the GPS satellite availability from FS04. Is simulated satellite info (sat #, elev, sig, etc.) available from FS04? I am simulating a GPS output in Arinc 429 format to a Universal UNS-1D FMS and would like to provide simulated satellite date rather than just canned data. Thanks for your help!

Ryan

[n4gix]

No. Such data isn't even "simulated," much less available. ;)

[Phantom Raider]

Thanks for your help, I figured there probably wasn't, but I thought I should still ask.

[airforce2]

The keplerian elements that describe the orbits of the 24 GPS birds are readily available in multiple venues on the internet. It's a relatively straightforward process to compute the azimuth and viewability of the sats for any given date/time (epoch). But...that said, it's a lot of computing power being devoted to a really esoteric piece of background data that one would almost never look at in real day-to-day ops.

Regards

[dfournie]

I'm using FS2004 to drive a GPS satellite simulator. The GPS sim is a UNIX based VXI/VME chassis that accepts an external input from FS2004 and outputs an RF signal to dual UNS-1F NCUs. The whole system also includes 3 EFI-890R displays, and dual RTUs. Works quite good. I've also experimented with sending the 429 GPS positional signal info directly into the UNS CDU as well. It just fakes out the internal NCU GPS and gives it a constant 8 sats with all DOPs of zero.

[airforce2]

Interesting...but what's it used for? Are you building a sim with real avioncs boxes? Sounds kinda expensive...

Cheers

[dfournie]

It's for a US Air Force King Air. It's a flight training device.

[Phantom Raider]

Thanks for your help guy's. After talking it over with some of my colleagues I decided to just use canned data. We have built a couple of RC-135 cockpit trainers, one for the A.F. and one for our SIL using FS2004 to drive both the UNS 1-D+ and associated equipment with glass displays. We put up a 30" LCD to show the visual. Pretty cool. Everyone who has seen it has gone out and bought their own copy of FS2004. Still have a few bugs to work out with the interface software. One problem is trying to capture the glide slope properly for an ILS approach. It is too aggressive sometimes and overshoots and ends up chasing the needle all the way down the glideslope. Very aggrevating. I'm also still having problems with winds. No matter what I tell FS2004 to do for winds the TAS and GS are always the same and thus the UNS calculates 0 winds. Still trying to figure this one out.

[dfournie]

Just use the localizer and glideslope deviations from FS2004 to drive the real instruments. We tune Nav1 inside FS2004 using the Universal RTU and then just send the respective localizer and glideslope information over CSDB to the displays. I can't recall off the top pf my head what we used for scaling, but it works quite well.