[WIP] Hydrophone Tracker/Quick Plotter

[Pisces]

Originally Posted by gutted

So do you think im wasing my time adding support for more than 3 bearings and averaging them?

in other words... we should just use bigger intervals between sightings intead?

Yes, small bearing changes/short intervals only make bad results. And many bad results do not average to a good one.

It's difficult to explain why. Your measurement accuracy cannot be better than 1 degree if you let your crew call out the degrees. Maybe better than 1 degree if you use the periscope bearing scale. But much worse if you have to listen for the sounds on the hydrophone yourself. Anyway, 1 degree off in for example a 4 degrees inerval means the target track during it is upto about 25% wrong in length. But 1 degree after a change of 10 degrees is only 10% wrong. 1 in 50 is 2%. The issue is called 'granularity'. Alot of bearing measurements over short intervals only means more work. The data is then all of the same bad quality. Longer intervals means less measurements and drawing work, and better accuracy. Trust me, patience pays of in reliability.

You could reuse old bearings by doubling the time interval. You keep bearing 1 as the baseline. Old bearing 2 is discarded. Old bearing 3 becomes new bearing 2, while the new bearing 3 is measured after the 4th short intervals. This way you get an early estimate on course and you may decide to let it go if if is moving away. But still get the luxury of better data.

If possible try to choose the interval so that the final bearing (3rd) to be when the target would show an AOB of 90 degrees, or when he would be the closest range from the listening location. That way the 4th bearing will get the best crossing when you move parallel to the target.