Having another think about this. Once you have the target's course and you have obtained the speed by holding it at a contant bearing on a parallel course, you can find the range. You can work it out with some trig, using the right angled triangle between where the AoB was 90 and your earliest recorded time when the bearing was at a five degree interval. Using the distance travelled at that speed in that time elapsed with the formula Opposite = Adjacent * Tan(Angle) to fine the distance to track. Or you can simply draw out the distance travelled and find where that distance fits in the triangle and that will give you the range.

Assuming that you can speed match of course, but if you can't, then you will have trouble intercepting the faster target.

It's getting slightly more complicated now though. :hmmm:.

:hmmm: Why do you need the range if you already have track and speed?

You have course and speed, but have no idea where the intercept point is unless you have range, so you'd have to approach purely on a constant bearing to guarantee an intercept, which is less than optimal.