must alsign hmd at cold start TGP SteerPoint Shows up in different location on the Helmet Display

[Gunnar81]

Hi all,

Getting back into flying the F16 a bit and I seem to remember this issue from when I was flying it before. Why am I getting an offset from where the TGP is point at a Steerpoint to where the Helmet is showing the steerpoint? Is this because I didn't boresight Mavericks? In the below screen snip I was using a GBU 12, the red circle was where my TPG was pointed but the helmet shows the symbology off by quite a bit. Any help would be appreciated.

[Muchocracker]

The helmet wasn't aligned during your coldstart. They added that function some years ago. 

[Moonshine]

That is true, yet even with a perfectly aligned helmet the TD box is off from where it should be. The TD box as seen in the HUD does not match the actual position the TGP is looking at as seen in the TGP page. So even without the HMCS the marker vs the tgp view is off.

most likely connected to the issue with excessive drift etc

made a short track to showcase.
- Airspawn -> so HMCS is "perfectly" aligned -> GPS is on, so i should not get much INS drift
- on the first pass the deviation is minimal as i have been flying for barely 5minutes.
- on the second pass the deviation is already easily visible, and im only flying for 15minutes
- on the third pass i use the HUD only (so i could not have thrown the symbology location off by doing a bad HMCS alignment) - still, TD box VS point tracked location on TGP is off quite significantly. and thats after 15 ish minutes. the longer you fly the worse it gets. no alignment will ever fix that.

this is also referenced here:

and here:

so, while you definitely MUST align the HMCS during a cold start to "not have that problem", it currently does not eliminate the problem, rather than just make it "a little less off"

TD_box_misaligned_vs_TGP_view.trk

Edited Sunday at 08:37 AM by Moonshine

[Furiz]

Hey I noticed the same a while ago but never got time to report,

when hot start in the air the HMD TD box will look at the same spot as TGP, but after some flying it starts to drift, I guess that's the INS drift that happens in the Viper, but we have GPS which is of no use there apparently.

But when in cold start with HMD and INS aligned, as soon as I got the the target area I noticed that TGP and HMD are not aligned, so it took no more than 5 min of flying and HMD TD box is about 5 to 10 feet off the target. That's in 5 mins, Imagine then in 30 mins of flying.

 F16 HMD not looking at same spot as TGP.trk

[Gunnar81]

22 hours ago, Muchocracker said:

The helmet wasn't aligned during your coldstart. They added that function some years ago. 

I figured it was something to do with this. Thanks I'll do some reading and test and report back.