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View Full Version : Estimated target speed - accuracy, how to change?


Stary Wuj
02-06-09, 04:48 AM
Hello!

I have some problems with target speed calculations, very annoying, how can I change accuracy of this data? I play 90% realism (outside camera ON) and I like it, no problems except of target speed readings.

How can I make this data more accurate, can I open some file and change some option? Which one?
Yesterday I missed Hiryu Fleet Carrier :damn: :wah: :rotfl: from the distance of 1800 meters because of bad estimated target speed, measured few times.

Heeeeeelp please :D

Have a nice day.

Stary Wuj

Rockin Robbins
02-06-09, 09:49 AM
There is absolutely no magic parameter that will make the speed estimate more accurate. It is perfectly accurate if your observations are perfectly accurate. Unfortunately, the stadimeter is not a perfect method of determining range. The further away the target is, the worse your range measurement is going to be. Subject to errors in the ID manual, there will be errors there too, which will render the estimate unreliable.

The much heralded speed estimate method actually isn't very useful at all, due to those realistic limitations. It is not a bug in SH4. It is a bug in the methodology of obtaining target position through the periscope. And it is entirely realistic.

I would recommend not using the speed estimate method unless there is no other way to determine speed. The best way is to mark two radar positions on the nav map three minutes apart. Measuring the distance between the points, the number of hundred yards is the target speed. 750 yards would be 7.5 knots. If you insist in using the lousy metric claptrap :-j, measure two positions three minutes fifteen seconds apart and the number of hundred meters is the speed in knots. This is accurate and you can rely on it.

By the way, get in close. 1800 meters is okay for a big target like a carrier, but I'd feel much more comfortable at 800.:arrgh!:

Sledgehammer427
02-06-09, 10:39 AM
RR said it best
i usuallly eyeball the speed, and then verify with the estimate.

if a carrier looks like its haulin, I'll set the speed for ~20 knots, it it loks like its dawlding, anywhere from 5-10 kts

Stary Wuj
02-09-09, 04:14 AM
But........... I don't want to play with map contacts updated, no God's eye :hmmm:

Stary Wuj

joegrundman
02-09-09, 04:44 AM
In which case you have to study, kohei

There are several ways to skin that cat, but none of them 100% reliable.

1. Using the radar you have. careful use of radar will give you speed estimates. it is easier if it is a convoy/task force since the radar display will give you a very good idea of the course of the convoy and this helps a lot.

It will take much more than 3 minutes however, but you can shadow the convoy beyond visual range and try to match course and speed with it until you are confident that you have it right. This can take hours, but equally it can take less time, and besides you can use time compression for this method without loss of accuracy.

2.Build one of these babies, the ISWAS

http://www.subsim.com/radioroom/showthread.php?t=106923&highlight=iswas

once mastered you can find the speed of the target on an intercept course by setting a collision course.

3. Estimate the length of the target, and pointing your bow at the target, measure the time it takes for the target to completely cross your bow. Then convert this measurement of target length/time into knots. The esxact formula you use depends on the units for your estimate of target length. Eg. if you estimate in meters, then meters/secs x1.8 = knots (x2 is good enough in practice). if you estimate in feet, then (feet/secs)/1.7 = knots

4. practice observing bow wake - you can find this helpful, although i do not use this as the primary method, it is useful for seeing if the ship has changed speed. Low speeds are easier to judge with this method, i find.

5. Stadimeter observations, and lots of them, and incorporate the AOB observation too in order to help you with the line of best fit, since range estimates vary so much. if you can rely on your ability to judge AOB by eye to help you with the target course it much reduces the effect of range error.

6. Mysteries of Target Motion Analysis!

and there are more!

Stary Wuj
02-10-09, 07:46 AM
In which case you have to study, kohei

There are several ways to skin that cat, but none of them 100% reliable.

1. Using the radar you have. careful use of radar will give you speed estimates. it is easier if it is a convoy/task force since the radar display will give you a very good idea of the course of the convoy and this helps a lot.

It will take much more than 3 minutes however, but you can shadow the convoy beyond visual range and try to match course and speed with it until you are confident that you have it right. This can take hours, but equally it can take less time, and besides you can use time compression for this method without loss of accuracy.

2.Build one of these babies, the ISWAS

http://www.subsim.com/radioroom/showthread.php?t=106923&highlight=iswas

once mastered you can find the speed of the target on an intercept course by setting a collision course.

3. Estimate the length of the target, and pointing your bow at the target, measure the time it takes for the target to completely cross your bow. Then convert this measurement of target length/time into knots. The esxact formula you use depends on the units for your estimate of target length. Eg. if you estimate in meters, then meters/secs x1.8 = knots (x2 is good enough in practice). if you estimate in feet, then (feet/secs)/1.7 = knots

4. practice observing bow wake - you can find this helpful, although i do not use this as the primary method, it is useful for seeing if the ship has changed speed. Low speeds are easier to judge with this method, i find.

5. Stadimeter observations, and lots of them, and incorporate the AOB observation too in order to help you with the line of best fit, since range estimates vary so much. if you can rely on your ability to judge AOB by eye to help you with the target course it much reduces the effect of range error.

6. Mysteries of Target Motion Analysis!

and there are more!

Thank You, option number 3 looks promising :DL

Stary Wuj

vanjast
02-10-09, 10:55 AM
Don't worry... all this is about to change :cool:

Stary Wuj
02-15-09, 09:39 AM
:hmmm: