SailNet Community - View Single Post - A Plug for Celestial Navigation
View Single Post
  #12  
Old 02-11-2010
wwilson's Avatar
wwilson wwilson is offline
Chesapeake Sailor
 
Join Date: Jul 2000
Location: Herrington Harbor, MD
Posts: 579
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 15
wwilson is on a distinguished road
Quote:
Originally Posted by AdamLein View Post
If anything, the solar flare problem is more an argument in favor of ensuring mariners are adequately trained in coastal piloting, not CN. According to the article, GPS is used by ships entering harbors, in which an error of tens of meters can mean the difference between safe passage and grounding, and also in which CN is never used.
Solar flare will NOT cause "tens of meters error". The article states 10 meters of uncertainty. Far less than the amount of uncertainty that "ships entering harbors" bore successfully before.

"Before it was turned off on May 1, 2000, typical Selective Availability errors were about 50 m (164 ft) horizontally and about 100 m (328 ft) vertically." Even with flaring, GPS will be no worse, and in fact considerably better than its pre May 2000 civil capability.

Last edited by wwilson; 02-11-2010 at 06:22 PM.
Reply With Quote Share with Facebook