INS creep correction

[jason_peters]

In several books it references the pilot correcting for INS precision. So they would set a waypoint to a known fixed structure (say a phone box or corner of a building) and then when arriving the waypoint would be slightly off and the pilot would update INS to the exact location

 

We don’t get to do that in DCS -

Is this not a thing now with GPS???

Interested if it’s a missing feature or I’m just out of date :)

[Emmy]

The Tomcat module can do this.

[QuiGon]

INS drift (as it is actually called) is indeed not a thing with GPS equipped aircraft, as GPS provides accurate and constant updates to the INS. However, there are multiple aircraft that have INS, but don't have GPS in DCS: M2000C, Viggen and the Tomcat with more to come. Their INS do all drift off to varying degrees with increasing flight time and can all perform a so called NAV FIX to update the INS with a known location (although it is currently bugged in the M2000C AFAIK).

 

There are actually various methods on how to perform a NAV FIX. They all have in common that you need to have a waypoint stored in your nav system for a position that is somewhat distinctive. The available methods to perform a NAV FIX depend on the aircraft and are as follows:

 

Visual Fix (available for pretty much all INS equipped aircraft): A visual fix is exactly what you described, so you fly over the visually recognizable position for which you already have a WP prestored in you NAV system and as soon as you're right above the position you perform the fix to tell the INS that this is the actual position of the WP.

 

Radar Fix (available for ground mapping radar equipped aircraft like the Viggen or even the F-14): The prestored WP needs top be on a position that is distinguishable on a radar picture (e.g. a mountain peak, a small island, a tall building). You then designate that position with the radar to tell the INS that this radar designated position is the actual position of the WP.

 

TACAN Fix (available for TACAN equipped aircraft like the F-14): The prestored WP needs to be on a TACAN station. You then tune your TACAN reciever to that station and once the signal is being recieved you tell the INS that the source of this signal is the actual WP positon.

 

There are some more nav fix methods that I'm not going to explain now, as these 3 are the most common ones.

Edited October 30, 2019 by QuiGon

[jason_peters]

So the F16 (my preferred ride) just uses GPS for updates??

[Harlikwin]

So the F16 (my preferred ride) just uses GPS for updates??

 

Yup. Your ride doesn't even have a NAV system really modeled at this point. But the 2007 version has a coupled GPS/INS, as does the hornet.

 

As other folks mentioned, the Viggen/F14/M2k have INS that can drift. And then you have the "old school" model migs and F5E that have no INS.

[Frederf]

Not just. All the GPS-enabled airplanes also have provision for updates without GPS. Whether the module does it or not is up to the developer. The A-10C, Ka-50, F-16 should but don't. Mirage half does it in that it does get drift and can update but the updates aren't accurate.

[QuiGon]

Not just. All the GPS-enabled airplanes also have provision for updates without GPS. Whether the module does it or not is up to the developer. The A-10C, Ka-50, F-16 should but don't.

I think ED will eventually implement proper INS functionality for both, the Viper and the Hornet, because on red side or on missions that predate a certain year (1980?), GPS is not available.

 

 

Mirage half does it in that it does get drift and can update but the updates aren't accurate.

IIRC it's exactly the opposite: The updates are currently always 100% accurate no matter how badly you perform them.