NavList:

Traditional position finding at sea with a sextant utilized the altitude of the body vs. the azimuth due to the diffuculty of measing the azimuth.

Now that we are in the 21st century, a couple of questions that I have been pondering.

1. Are their any automated devices in existence that can measure the azimuth of a number of celestial bodies and calculate a position when they are visible?  Has technology advanced to a point where this is practical?

2. Given the diffuculty of measuring the azimuth of a body with any level of accuracy unless it is on or near the horizon let's assume that you could get a true observed bearing withing 5° of the true bearing on either side of the true bearing. No matter where it is located in the sky.  An arc of 10°.   Maybe someone with better math skills than mine could deduce:

a.  What the maximum error from your true position would be given the bearings make a perfect 90° angle to each other?

b. What the maximum error would be if you shot 3 bodies 60° apart?

c. How about 4 bodies 30° apart?

d. How many bodies would you need to measure to get an accuracy withing 30 nm's? If at all possible.

e.  Would the geographic position of the body have any bearing (no pun intended) on the answers to a through d.

Thanks!

Doug MacPherson

38-34 N, 121-28 W