INS Alignment

[ClausHoffmann]

I have build myself a training mission on the Nevada map to do some navigation training. In the mission editor the position of the aircraft (Nellis AFB) is N036°14`29`` W115°02´02´´. In game on the map view (F10) this coordinates are still true. In the cockpit the current position is shown on the HSI page as N036°14´48´´ W115°02´04´´ (regardless of using Waypoint 0 or A/C as reference). If GPS is used as source for the position, this again shows the same coordinates. This coordinates are also shown on the map display while aligning INS and they are the result of the alignment.

 

I tried to change the coordinates on the HSI page to the ones shown in the ME prior to alignment, but the alignment still followed the slightly different coordinates originally on the HSI.

 

Ho to do the alignment correct and which are the correct coordinates in the first place? Thank you in advance for any advice or clarification.

[Ziptie]

Is it that the coordinates for your aircraft, upon INS completion are simply not in the "exact" spot as the coordinates for the marker at the airfield? It seems that the two are incredibly close, in terms of GPS coordinates, and might be related to the parking/spawn point of the airframe...?

 

This isn't causing you trouble for locating the airfield upon RTB correct?

 

 

Cheers,

 

Don (callsign Ziptie)

[ClausHoffmann]

No, its not giving me an issue for returning to base, as I use the TACAN 12X approach on RW 21L for this training mission.

 

 

 

I was just wondering, if I would use INS-guided bombs in this mission, that might play a role, does it?. I have honestly no idea, whether the difference in the coordinates is significant or not. I understand, that I could just ignore the difference?

[Tholozor]

The Hornet's Mission Computer starts in DDM format (degree decimal-minutes). That's where your discrepancy is coming from. You can change the format to DMS (degree minute seconds) in the HSI -> DATA -> A/C subpage.

 

According to your ME start position (N36°14'29" W115°02'02"), 29 out of 60 seconds is 0.48 minutes (giving us N36°14.48' in DDM) and 2 out of 60 seconds is 0.03 minutes (giving us W115°02.03' in DDM). The Longitutde probably rounds up because of decimal-seconds that are not displayed, but can be shown with a format change in the ME map and in the HSI -> DATA -> WYPT subpage with the PRECISE option.

Edited December 26, 2019 by Tholozor

[ClausHoffmann]

Thank you very much, I will try this. Its obviously the same issue as with the Mirage 2000.

[ClausHoffmann]

I tried it and you are completely right, this was the issue. I now feel assured that I am doing it right, thank you very much. It remains the question, why there are to norms in DCS in the first place!

[Harker]

Has nothing to do with DCS itself, it's just that different aircraft have different systems and default units.