Normal alignment vs stored

[Gunfreak]

So when  I do cold starts, I usually do stored alignment,  partly because I'm lazy and partly because I'm impatient. 

I assume the only difference between stored and normal(if the stored alignment is correct) is that normal is slightly more accurate ?(6 vs 10)

[Tholozor]

With one of the latest updates, normal alignment can only get to status 10 alignment quality, same as Stored Heading, so there's no difference unless you have to re-align after a shutdown somewhere else. There's a whole process for enhancing the alignment to status 6, but isn't implemented.

Edited August 22, 2021 by Tholozor

[Jenson]

24 minutes ago, Tholozor said:

With one of the latest updates, normal alignment can only get to statis 10 alignment quality, same as Stored Heading, so there's no difference unless you have to re-align after a shutdown somewhere else. There's a whole process for enhancing the alignment to status 6, but isn't implemented.

 

May I ask what does 10 and 6 stand for? is it in feet or just a numeric value? Thanks. 

[Tholozor]

AFAIK, I'm sure someone can explain it better, it's a general representation of the CEP of the aircraft (how sure it is of its position/attitude/heading), but not necessarily by a physical measurement. The Enhanced Interrupted Alignment process to get to status 6 just tightens it up a little more, but takes a lot longer to perform.

Edited August 11, 2021 by Tholozor

[Frederf]

The status number refers to a multiplication of the normal standard drift performance of the INS, in tenths. So status "10" is 1.0x drift. Status "30" is 3.0x or three times the normal drift rate. So if status 10 performance is 0.8nm/h then status 30 is 2.4nm/h. It's not a total indication of INS performance because there are other factors in alignment quality. E.g. a normal alignment 10 is equal than a stored heading 10 in some aspects but superior in others.

 

Status 6 is reserved for EIA because it's about 40% better than a normal alignment.

[Machalot]

Is that a drift rate assuming unaided INS? With GPS aiding the system should be long term stable, as if the effective drift rate were near zero. 

[Frederf]

Yes