INS Alignment : How Precise Does It Need To Be?

[flyingace]

Hi all,

 

As the f-16 now has functions that require the INS to be aligned , I was wondering how precise the alignment needs to be. In the INS page displayed on the DED it counts down from 99 to 6, but is there any need to wait the extra 4 minutes for it to reach 6, or is functionality the same no matter how accurately it aligns itself.

 

Thanks,

 

Flying ace

[lee1hy]

It need for Link16 datalink

[flyingace]

Hi lee1hi,

 

But would the data link still function to its full capability even if the INS does not align to its highest level of precision (a 6 on the DED page)

[Weasel]

Hello flyingace

 

As far as I know (especially with the Hornet) a correct INS alignment is very important for a lot of functions and systems (JDAM, navigation etc). Yes a lot of functions are still working not correctly and still very much wip but it's very important anyway.

 

There was a fantastic post in the forum which system only work correctly with a right INS alignment. It was in the hornet part but I am sure it's valid for the viper as well (will look if I find the thread)

 

Just found the thread:

 

https://forums.eagle.ru/showpost.php?p=3623574&postcount=6

Edited December 14, 2019 by Weasel
Adding thread

[will-]

[flyingace]

Thanks so much weasel. I didn’t realise so many systems depended on INS. The thread was very useful and thanks for your time :)

[Weasel]

Thanks so much weasel. I didn’t realise so many systems depended on INS. The thread was very useful and thanks for your time :)

You're welcome mate, happy to help you

[CobaltUK]

I go as soon as Ready is displayed (unless I am busy with other stuff in which case I let it run further obviously) and as yet have no issues. That might change when the lacking sp features are available. PPT`s likely to need maximum precision if its actually modeled.

Edited December 14, 2019 by CobaltUK

[Napa]

A really good precise alignment would be around 8.5 mins and alignment of 6.

[Notso]

Thanks so much weasel. I didn’t realise so many systems depended on INS. The thread was very useful and thanks for your time :)

 

In a modern combat aircraft, almost every system relies on the INS and/or GPS working correctly with high quality data. A specific INS alignment quality or GPS position quality are often GO/NO GO items.

 

Most systems that now use an integrated INS/GPS nav computer (usually called an EGI - pronounced Eggy) Enhanced GPS-INS unit black box - the parking spot ramp coordinates are no longer required to be input into the jet for alignment. Once the jet has enough Satellites to track for a high quality FOM, the GPS will automatically align the INS on the ground and keep it updated throughout the flight. In the past, before GPS became ubiquitous, the pilot would have to manually align the INS on the ground to his/her specific parking coordinates and then manually update the INS during the flight using the TPOD or the A/G radar (or even an overly mark point) to known locations on the ground as the INS would usually drift over time. Even the best INS's could drift up to a mile or more over the course of a 1.5 hour sortie.

[HayMak3r]

Sorry to hijack, but thought maybe this could also be sorta relevant. I have always waited on the ground until rdy/align started blinking and I go to NAV before moving at all. Can you start taxiing preparing for takeoff once rdy shows up? When is the best time to start, so as to get a full alignment.

 

Thanks!

[CobaltUK]

The earliest rdy/align (in this sim as of now) allows me to fly to entered SP well over 100 miles away but as I already said its not likely good enough for weapon delivery I.E PPT.

 

So yes you can select NAV and set off on mission if you only need to navigate to a SP, not for precise TGT location. WAGS video and probably the docs also, describe the process in full.

 

At the moment, rdy/align is fine for mp servers.

[sobek]

Sorry to hijack, but thought maybe this could also be sorta relevant. I have always waited on the ground until rdy/align started blinking and I go to NAV before moving at all. Can you start taxiing preparing for takeoff once rdy shows up? When is the best time to start, so as to get a full alignment.

 

Thanks!

 

 

Once the generator comes online, you can start powering up the avionics and start alignment. Using the stored heading mode, you can get down to 10 in about 1.5 minutes, then switch to normal alignment and you get down to 6 in about 2.1 minutes total.

[HayMak3r]

oh really? But, are you still parked? I know the process, but I guess it doesn't really answer my question of when you can actually start rolling without messing up the alignment. For a full alignment the documentation only states it should take about 8 minutes and to do it prior to taxi. This quick method then I should assume is the same?

 

I can wait the 2.1 minutes though. I didn't know I could switch to full align and get the rest of the way down to 6. Cheers!

[CobaltUK]

You cant move/roll until you move switch to nav. If you do u will corrupt the alignment. If you select nav, move, stop and select Align again it re starts from the beginning. Until you are dropping lgbs on pre planned tgts (PPT`s) then not much stopping you taking off as soon as RDY comes up. (in my experience so far)

[HayMak3r]

You cant move/roll until you move switch to nav. If you do u will corrupt the alignment. If you select nav, move, stop and select Align again it re starts from the beginning. Until you are dropping lgbs on pre planned tgts (PPT`s) then not much stopping you taking off as soon as RDY comes up. (in my experience so far)

Thanks! That is what I was really wanting to confirm. I mean I don't mind sitting there waiting, but if I haven't had to all these times I've flown I was going to be frustrated with myself haha.

[Frederf]

You cant move/roll until you move switch to nav. If you do u will corrupt the alignment. If you select nav, move, stop and select Align again it re starts from the beginning. Until you are dropping lgbs on pre planned tgts (PPT`s) then not much stopping you taking off as soon as RDY comes up. (in my experience so far)

Not how the real airplane work

[Emmy]

Not how the real airplane work

 

Cite?

[CobaltUK]

Not how the real airplane work

 

 

We don't have the real jet. What's your point? We all hope realism will improve with this sim.

[Frederf]

Cite?

The F-16 will auto-nav taxiing with knob in the align position provided the status is 70 or less. During normal (not stored) alignment the performance improves during subsequent stationary periods up to the normal status 10 performance. Status 6 (better than 10) performance is a slightly different process involving alignments at different orientations.

 

Taxiing in NORM always has the potential for improving the INS regardless of how complete the initial alignment session was except for the special interrupted alignment process. At worst it doesn't improve it. Especially with GPS-aiding, "forgetting" the knob in NORM as habit before taxing and NAV before takeoff would be absolutely a fine thing to do.