NavList:

Hi Peter.

Thanks for the link to the article at GPS World. I used to read that regularly when I had a hard-copy subscription but I just don't get around to it now. So the directionality is then the obvious solution (in fact it wouldn't surprise me if I had read something alluding to that in an earlier column by Richard Langley himself). The system proposed in this recent article seems to be designed for immediate and continuous spoofing detection. It would detect a spoofed signal in a second or so. That strikes me as over-kill except perhaps in military systems. Limiting ourselves for the moment to surface vessels, if I can detect a spoofed signal at once a minute intervals, that would surely be enough (except in piloting waters --and there you have to worry about radar anyway). It would be enough for vessel safety, and it would be enough to render spoofing almost worthless. It strikes me that a "once-a-minute spoofer detector" would be relatively cheap to build. It would also be a an add-on. No need to replace existing systems.

You wrote:
"Is celestial immune, though? It could be spoofed with enough
resources. Deploy a number of UAVs around the ship. Some are
equipped with small screens, which would be interposed between the
real stars and the user's sextant."

Sure. You could just drop a big planetarium dome over the vessel, and then you've got 'em right where you want 'em!! ;) I would say that spoofing the stars is too preposterous even for the most diabolical super-villain. Not that it couldn't be done. But rather it's the sort of thing that would get the other super-villains laughing at anyone who tried to pull it off.

-FER

----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------