TMA

BLACK!!! · 04-06-06, 09:47 AM

Hey guys, I have a question regarding tma.

When I have a merged contact on the tma screen, it seems to me more confusing than using only one sensor.
I know from sc that the real position of the object should be at an intersection of the LOS from the two sensors.
That isn't true for DW, or is it?
Does anybody else has this problem?
Thanks for your answers

Black

Molon Labe · 04-06-06, 02:29 PM

It will only be at the intersection point if the two sensors are in different positions, for example, if one sensor is a distant UUV or the towed array. There will be some inaccuracy, as with any bearing, but this will be reduced by greater lateral separation of the two sensors.

compressioncut · 04-06-06, 02:35 PM

When you say line of sound do you mean the LOS on the TMA plot or the bearing line on the navmap? If you have two bearing lines on the navmap that intersect (say, from the tail and a sonobuoy), then yes, where they intersect should be about where the contact is more or less, allowing for bearing errors inherent to the sensors. The inaccuracies of the sensors create what's called an "area of probability," or AOP. The angle of the intersection also contributes to the size of the AOP.

Also keep in mind that intersecting bearing lines don't mean you have a merged track. A merged track is one that has been tracked on multiple sensors, and then merged into a single NTDS symbol on the navmap, with tracking/indicating (course/speed) information shown in the contact summary box. I don't believe you can merge sonobuoy contacts, although aircraft will link them out as what look like merge tracks.

Now, if you mean the LOS lines on the TMA plot, then no, the target is not necessarily located at the intersection of the lines. The intersection can mean any number of things depending on yours and the target's course and speed, and the relationship between them.

BLACK!!! · 04-06-06, 02:52 PM

I'm only talking about TMA in a sub.
Is the inaccuracy small enough to get firering solution?
It's a little bit confusing to me because in sub command the intersection was the exact location of the enemy ship.

Molon Labe · 04-06-06, 03:50 PM

There was some inaccuracy involved in SC intersection points as well, in fact, as far as I can tell, intersection points in DW are more precise than they were in SC (an indication that the bearings sent to TMA, when not corrupted, are slightly more accurate than in SC).

My best guess as to what might be causing the difference is that in DW, when the TA is turning, the bearing line is off the mark and needs to be disregarded. Any intersection that line makes with a line from any other sensor is pure junk.

MaHuJa · 04-12-06, 07:41 AM

Quote:

Originally Posted by compressioncut

I don't believe you can merge sonobuoy contacts, although aircraft will link them out as what look like merge tracks.

Correction: AI aircraft.

04-06-06, 09:47 AM	#1
BLACK!!! Nub Join Date: Apr 2005 Posts: 2 Downloads: 8 Uploads: 0	TMA Hey guys, I have a question regarding tma. When I have a merged contact on the tma screen, it seems to me more confusing than using only one sensor. I know from sc that the real position of the object should be at an intersection of the LOS from the two sensors. That isn't true for DW, or is it? Does anybody else has this problem? Thanks for your answers Black

04-06-06, 02:29 PM	#2
Molon Labe Silent Hunter Join Date: Jun 2004 Location: Along the Watchtower Posts: 3,810 Downloads: 27 Uploads: 5	It will only be at the intersection point if the two sensors are in different positions, for example, if one sensor is a distant UUV or the towed array. There will be some inaccuracy, as with any bearing, but this will be reduced by greater lateral separation of the two sensors. __________________

04-06-06, 02:35 PM	#3
compressioncut Loader Join Date: Jun 2003 Location: Canada Posts: 90 Downloads: 5 Uploads: 0	When you say line of sound do you mean the LOS on the TMA plot or the bearing line on the navmap? If you have two bearing lines on the navmap that intersect (say, from the tail and a sonobuoy), then yes, where they intersect should be about where the contact is more or less, allowing for bearing errors inherent to the sensors. The inaccuracies of the sensors create what's called an "area of probability," or AOP. The angle of the intersection also contributes to the size of the AOP. Also keep in mind that intersecting bearing lines don't mean you have a merged track. A merged track is one that has been tracked on multiple sensors, and then merged into a single NTDS symbol on the navmap, with tracking/indicating (course/speed) information shown in the contact summary box. I don't believe you can merge sonobuoy contacts, although aircraft will link them out as what look like merge tracks. Now, if you mean the LOS lines on the TMA plot, then no, the target is not necessarily located at the intersection of the lines. The intersection can mean any number of things depending on yours and the target's course and speed, and the relationship between them. __________________

04-06-06, 03:50 PM	#5
Molon Labe Silent Hunter Join Date: Jun 2004 Location: Along the Watchtower Posts: 3,810 Downloads: 27 Uploads: 5	There was some inaccuracy involved in SC intersection points as well, in fact, as far as I can tell, intersection points in DW are more precise than they were in SC (an indication that the bearings sent to TMA, when not corrupted, are slightly more accurate than in SC). My best guess as to what might be causing the difference is that in DW, when the TA is turning, the bearing line is off the mark and needs to be disregarded. Any intersection that line makes with a line from any other sensor is pure junk. __________________

04-06-06, 02:52 PM	#4
BLACK!!! Nub Join Date: Apr 2005 Posts: 2 Downloads: 8 Uploads: 0	I'm only talking about TMA in a sub. Is the inaccuracy small enough to get firering solution? It's a little bit confusing to me because in sub command the intersection was the exact location of the enemy ship.