[11Bravo]

Now we are back at port let us talk about accuracy of positional measurement. Let us assume for now that SH3 displays the positions of the stars correctly. We can't determine that without an accurate sextant, so we will have to assume it for now. What type of measurement errors could we expect?

We need to think about the resolution of time and position. We need to think about what is possible. And what is necessary.

If we have a 8km or 16km environment for micro scale work like hydrophones or visual, then I think we can agree that 30km or 120km accuracy is good enough for macro scale work like rough positioning. Is that possible in SH3?

We should consider time first. SH3 has a stop watch that allows seconds to be added to the two clocks. My testing shows that the seconds are good to about 5 seconds for normal use. Heavy time compression and extended use will actually cause the second hand to stop working on 1X TC. Let the stopwatch run for 24 hours and it keeps accurate to about 5 seconds. Reset it when necessary and it is definitely good to 5 seconds and probably 1 second accuracy.

What does that mean?

If we assume 24 hours = 360 degrees for a celestial body, 5 seconds would indicate time errors of 0.02° or 2.5 km on planet SH3. Clearly, time will not be the limiting factor in positional accuracy. Even if we ignored seconds, 1 minute accuracy would allow 0.25° accuracy or 30 km.

Now let us consider position. SH3 is based on a 1024x768 pixel interface. Celestial navigation depends on the measurement of the altitude of the heavenly body from the horizon. The maximum altitude is 90°. If we try to measure 90° with 768 pixels to 1 pixel accuracy, we will have a minimum error of 0.12° or 14 km. We could cut this in half if we used 2 fields of view. But with eyeball measurements we shouldn't expect it better than about 14 km.

If the celestial model is not correct, we will have to create our own model that accurately predicts the SH3 displays.

I can tell you right now (but will show you later) that the star positions in SH3 are more accurate than can be displayed in the SH3 design.

What does it mean?

It means that SH3 is capable of more accuracy than the user interface is possible of allowing. My estimate is that the theoretical accuracy is 15 km because of the resolution of the gui. (See the picture above) My goal is to create a method good to 30 km. I will accept an accuracy of 120 km as useful for game purposes. Most of the time. Assuming a sober kaleun.