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GPS is not yours!
I posted this elsewhere, but the information deserves its own thread.
I know little of offshore boating, and almost nothing about sailing. What I do know a lot about is GPS. With a Dad that works for NASA in Florida, and an Aunt who literaly wrote the manual for the first GPS reciver in the 80's for ground infantry in the army, I come from a family in the know. I wrote a college thesis on GPS technology as well.
The most imporatant thing to remmember is that GPS is made up of two seperate components, the reciever, and the Transmitter. You have complete control over the reciever. You can buy recievers that are almost indestructable, water proof, and I would say much more reliable than a sextant.
But the reciever is only half of what is required to use GPS. Almost everyone in the United States relies on the Department of Defenses NAVSAT Array, a series of 24 satalites that your recevier uses to triangulate a position. The Russians have an incomplete array, and the EU is planning to put up an array, GLOBAL something or other.
First and formost thouse satalites are for the deffense of this nation, and will, and have been used as such! The military did not release the full potentional of the GPS system untill Clinton told them to unscramble the signal in 2000 (then called Selective Avalablity) And they withold the ability to rescramble and even stop the signal for use by the military if they need it.
For example, in the Iraq war they would move as many of the NAVSAT sattlites as possible over Iraq (up to 7 of the 24), then program them to compensate for weather affecting the signal, and this is just what has been declassified! Do you think a civilian GPS recevier worked anywhere near Iraq during the first months of the war?
And this is just what the Department of Defense can do to the signal, what about solar interference that can make gapping holes in satilite coverage, or space trash destorying satilites? God forbid your the only one relying on GPS for navigation when the military moves a sattlite from over the south pacific to fill a hole in thier covarage elsewhere.
Dont take GPS for granted, its not yours! Only the reciver in your pocket is yours. On the other hand, a sextant is yours, you have control over it. You can drop it on the deck, but at least you will know why it doesnt work!