[time-nuts] GPS position averaging

[Mark Sims]

Take a look at the code in Lady Heather that does a 48 hour precision survey.   It calculates a weighted median position of fixes over 1 hour periods then calculates a final position from those medians.  The algorithm was developed by having people around the world with Thunderbolts and quality antennas and surveyed antenna positions log data for 48 hours.  I processed the data and did some voodoo to come up with the weights, etc that minimized the error in the calculated positions from the surveyed positions.   The 48 hour survey interval minimizes the effects of multi-path and satellite orbits, etc.