SUBSIM Radio Room Forums - View Single Post - Determining course of contact that is "smoke on the horizon"

Jaystew · 06-16-14, 03:16 AM

I didn't even think it was that good but I'm glad you guys like it. Here is part two.

The angles are not proper and only exaggerations but technically correct. You can infer alot from the angles without them being correct. Such as approximate distance and approximate direction based on where your best guess position is.

For example, so the mid range of where your plots are put the target at 15 km from your sub which is probably right. More right than if its in the range of 5km or 25 km logically if it is just on the horizon is must be in visual range which rules out 25km and if it is so small you cant make out what direction the bow is facing then it must be greater than 5km. So 15km it is approximately. Now every 2 min you can draw an approximate line between points about 15km from your sub along the lines of bearing from your visual observations which will be accurate. This will give you a general direction of travel. If you are very accurate with your time and speed keeping you will have a course of your target within 10-20 degrees with only 3 measurements. The more measurements the more accurate the inferred conclusions derived from the data.

Some considerations...

The target is moving so even if your measuring is accurate it will not explain why everything does not exactly line up. The target may also be zigzagging likely and this will add to variability in your best guess. The conclusions will derive from the best observations which will be the last 3 you made, but do not discount the previous observations and recording as they will serve to confirm direction of travel and/or conflict with your course plotting.

Also. The target may change course. If they have detected you or on the whim of the captain. In which case you may not longer need to make observations in the case where they are heading towards you to attack, or where you will need to continue to observe to again determine their new course. With even more observations you can determine their course sufficient to match it and then run parallel.

Once parallel you can increase or decrease speed to determine the speed of your contact. This will be in lesson 3 which I'll put together laters.

Oh yeah, use the nomograph to determine how much distance you travel at 10kts in 2 min. Knowing this will help you to know the larger triangle problem.

Here is a link to the grand tutorial...
http://imgur.com/a/EstMH#0

06-16-14, 03:16 AM	#5
Jaystew Sparky Join Date: Apr 2013 Posts: 151 Downloads: 50 Uploads: 0	I didn't even think it was that good but I'm glad you guys like it. Here is part two. The angles are not proper and only exaggerations but technically correct. You can infer alot from the angles without them being correct. Such as approximate distance and approximate direction based on where your best guess position is. For example, so the mid range of where your plots are put the target at 15 km from your sub which is probably right. More right than if its in the range of 5km or 25 km logically if it is just on the horizon is must be in visual range which rules out 25km and if it is so small you cant make out what direction the bow is facing then it must be greater than 5km. So 15km it is approximately. Now every 2 min you can draw an approximate line between points about 15km from your sub along the lines of bearing from your visual observations which will be accurate. This will give you a general direction of travel. If you are very accurate with your time and speed keeping you will have a course of your target within 10-20 degrees with only 3 measurements. The more measurements the more accurate the inferred conclusions derived from the data. Some considerations... The target is moving so even if your measuring is accurate it will not explain why everything does not exactly line up. The target may also be zigzagging likely and this will add to variability in your best guess. The conclusions will derive from the best observations which will be the last 3 you made, but do not discount the previous observations and recording as they will serve to confirm direction of travel and/or conflict with your course plotting. Also. The target may change course. If they have detected you or on the whim of the captain. In which case you may not longer need to make observations in the case where they are heading towards you to attack, or where you will need to continue to observe to again determine their new course. With even more observations you can determine their course sufficient to match it and then run parallel. Once parallel you can increase or decrease speed to determine the speed of your contact. This will be in lesson 3 which I'll put together laters. Oh yeah, use the nomograph to determine how much distance you travel at 10kts in 2 min. Knowing this will help you to know the larger triangle problem. Here is a link to the grand tutorial... http://imgur.com/a/EstMH#0 Last edited by Jaystew; 06-18-14 at 05:51 AM.