Submarine navigation

Linton · 09-01-08, 03:40 PM

When were pool of error calculations first introduced and can anybody tell me a little more about them?

Linton · 09-02-08, 03:36 AM

I was hoping SeaQueen could answer this.

Dr.Sid · 09-02-08, 06:05 AM

More patience .. she will at least say 'that's classified'

I'm interested too, actually I plan to implement this problem into my sim somehow, so any info would be appreciated.

Pisces · 09-02-08, 07:25 AM

What does "pool of error" mean anyway? Just merging of uncertain data?

Dr.Sid · 09-02-08, 08:20 AM

My wild guess .. when using inertial navigation, you have starting point and you measure changes (acceleration, rotation) .. and you compute your actual position from that. Since you can only measure the changes with some degree of precision, you get errors and they accumulate, since every position is based on previous one.
Let's say you start with known location, and after hour you know your location with estimated error 10 meters. It may depend not only on time, but also on acceleration, rotation and so on. For example your system can get confused by sudden shocks or vibration.
If someone says pool of error I guess he means the area the sub may be in. At starting point it is a point (or area based on method used to obtain starting fix .. on open seas it can be stars, sun, GPS, radio). Then you go under the water and the area gets larger and larger. I guess that only circular error is estimated so you can at any time draw circle around your estimated position, where radius of the circle is the estimated error.

I guess you must estimate the error even in manual navigation, except mechanical/computer navigation system can estimate it much better and it can really draw the circle where it is quite sure you are in (as many GPS do).

However since when and how it's done on real subs, I don't know. I only remember that in Submarine from Clancy there is said that LA can find harbor in Mediterranean when starting at US cost with no need to surface.

Pisces · 09-02-08, 02:57 PM

He either means "dead-reckoning", which is very old, no doubt age of sail. Or a very modern computer kind of navigation. There must be a translation thing going on here.

09-01-08, 03:40 PM	#1
Linton Sea Lord Join Date: Dec 2003 Posts: 1,898 Downloads: 0 Uploads: 0	Submarine navigation When were pool of error calculations first introduced and can anybody tell me a little more about them? __________________ http://lintonsview.blogspot.com/

09-02-08, 03:36 AM	#2
Linton Sea Lord Join Date: Dec 2003 Posts: 1,898 Downloads: 0 Uploads: 0	I was hoping SeaQueen could answer this. __________________ http://lintonsview.blogspot.com/

09-02-08, 06:05 AM	#3
Dr.Sid The Old Man Join Date: May 2005 Location: Czech Republic Posts: 1,458 Downloads: 6 Uploads: 0	More patience .. she will at least say 'that's classified' I'm interested too, actually I plan to implement this problem into my sim somehow, so any info would be appreciated. __________________ ComSubSim forum at CADC

09-02-08, 08:20 AM	#5
Dr.Sid The Old Man Join Date: May 2005 Location: Czech Republic Posts: 1,458 Downloads: 6 Uploads: 0	My wild guess .. when using inertial navigation, you have starting point and you measure changes (acceleration, rotation) .. and you compute your actual position from that. Since you can only measure the changes with some degree of precision, you get errors and they accumulate, since every position is based on previous one. Let's say you start with known location, and after hour you know your location with estimated error 10 meters. It may depend not only on time, but also on acceleration, rotation and so on. For example your system can get confused by sudden shocks or vibration. If someone says pool of error I guess he means the area the sub may be in. At starting point it is a point (or area based on method used to obtain starting fix .. on open seas it can be stars, sun, GPS, radio). Then you go under the water and the area gets larger and larger. I guess that only circular error is estimated so you can at any time draw circle around your estimated position, where radius of the circle is the estimated error. I guess you must estimate the error even in manual navigation, except mechanical/computer navigation system can estimate it much better and it can really draw the circle where it is quite sure you are in (as many GPS do). However since when and how it's done on real subs, I don't know. I only remember that in Submarine from Clancy there is said that LA can find harbor in Mediterranean when starting at US cost with no need to surface. __________________ ComSubSim forum at CADC

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09-02-08, 07:25 AM	#4
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	What does "pool of error" mean anyway? Just merging of uncertain data?

09-02-08, 02:57 PM	#6
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	He either means "dead-reckoning", which is very old, no doubt age of sail. Or a very modern computer kind of navigation. There must be a translation thing going on here.