[LEAPSECS] Another reason not to mess with UTC

[Rob Seaman]

You did note the section (http://catless.ncl.ac.uk/Risks/25.95.html#subj1):

"A test done in 2008 showed that it was easy to badly spoof ships of the
English coast, causing them to read locations anywhere from Ireland to
Scandinavia."

GPS is being built into critical infrastructure, for instance, for shipping and air traffic.  One can certainly imagine Somali pirates finding jamming technology extremely attractive.

Precision timekeeping was invented for navigation at sea.  Ship's captains already know how to use sextants.  The comment about brass is hyperbole.

If traditional navigation based on mean solar time is not to be the fallback to GPS - then what is?

Rob
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On Mar 1, 2010, at 12:26 AM, Poul-Henning Kamp wrote:


> In message <A39F772D-CA72-4DC6-86CF-73306DB34958 at noao.edu>, Rob Seaman writes:

>> RISKS Digest on "the growing threat of jamming to satellite navigation systems":

> 

>> It sure would be peachy to retain a capability to fall back on

>> traditional navigation techniques.  Access to mean solar time as

>> provided by UTC is part of the recipe.

> 

> I can imagine the page hidden somewhere in the rear of the Mercedes

> instruction booklet:

> 

> 	"In case your GPS navigation detects jamming, a electronic

> 	drawer will automatically open below the navigation display

> 	and reveal a brass sextant, which is to be used as follows:

> 

> 	At local solar noon adjust the knob A such that...

> 

> 	"

> 

> Yes, I can see that work...

> 

> Poul-Henning