More on loss of GPS due to solar flares.

[cliff]

[ QUOTE ]
having done much original work in antipodal propagation

[/ QUOTE ]Shaggin' Sheilas? /forums/images/graemlins/smirk.gif

Sorry - could not resist that one.
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[Ships_Cat]

Would you believe propagating, errr, orchids, potatoes, or maybe tomatoes? /forums/images/graemlins/smile.gif.

Your interpretation had not crossed my pure mind - must be more careful with my antipodal phraseology in future and get back to my more natural "Gidday Mayt, Howsya goin todaye. Allright Ay? /forums/images/graemlins/smile.gif.

John

 

[jimbaerselman]

Lets suck a couple of points out of this thread.

Civilian GPS is a US supplied international resource.

The US have undertaken to support the reliability and accuracy of this resource to the level that it can be used in safety critical applications (blind aircraft approaches to airfields).

There is an industry of well qualified people out there independently assessing the reliability, accuracy and usability of the system (including the political reliability) to determine how far the system could take an aircraft towards automatic landing without introducing a chance of more than 1 in 10,000,000 landings leading to an accident.

In my view this implies that leisure sailors need not worry one jot about the signal. They should, instead, worry about their 'usability' factor - pilot error. The failures most likely to affect a sailor's use of GPS are power failure, instrument failure due to breakage, incorrect selection of map datum, incorrect waypoint entry, selecting an incorrect display mode etc. - all probable events.

For these reasons sailors relying on GPS should have a back up - however simple that backup may be.

And, let's face it, a DR position on a chart rapidly becomes very inaccurate, so it is a very crude and unreliable back up, suitable only for use in good visibility, or when approaching a coast which has no offshore dangers.

 

[cliff]

[ QUOTE ]
Would you believe propagating, errr, orchids, potatoes, or maybe tomatoes? /forums/images/graemlins/smile.gif.
John

[/ QUOTE ]Actually I found propagating poppies or cannibis was more stimulating not to mention rewarding /forums/images/graemlins/smirk.gif - that was until one of the profs realised what we were doing /forums/images/graemlins/grin.gif
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[Gunfleet]

military/non-military gps

I live in a very military town and every time that nice Mr Blair sends them off on another adventure somewhere remote we see the same phenomenon - the shop shelves empty of gps and fleeces!

The army may not issue civvy gps but the soldiers use them.