(von GerdS, 17.12.2001)
Ich habe hier einen interessanten Beitrag in einer Newsgroup entdeckt. Die amis sind demnach in der Lage, die GPS-Genauigkeit auf engstem Raum temporär extrem zu verschlechtern.
"Red Rider" <seethe@text.net> schrieb im Newsbeitrag news:<u1qeitntv23e93@corp.supernews.com>...
> Danny Morris wrote in message ...
> >As a member of a search and rescue team in Virginina (USA), I was told
> today
> >that SA was back on in certain areas. The areas would vary.
> >
> >Any other info about this?
> >
> >anny
> >
>
> While I can't say I have heard any official word, something is being turned
> on and off, at what seems to me to be random intervals, at least in my area
> of the east coast.
>
> I am a commercial fisherman, and I know for a fact that fixed Navaids,
> bridges, islands, and docks, don't move. But in the last three months, my
> GPS on my smaller boat, has started occasionally showing some position
> errors, in excess to 100 yards at times. (I only use 2D, as I am at sea
> level, so I have no need for 3D so the elevation inaccuracy problem is
> eliminated). These errors have to be to turned on and off by someone,
> because there haven't been there since SA was officially turned off. And I
> am not the only one here that has noticed it.
>
> On my other larger boat, I have a DGPS receiver/antenna hooked to my GPS,
> plus I also have a Loran C receiver. I have taken my handheld GPS from the
> small boat and have occasionally seen the errors on it, but not on the DGPS
> hooked up GPS, or on the Loran.
>
> Another reason I think this is happening is that I operate my boats next to
> one of the largest military bases on the East Coast. When the error is
> present it seems to affect my GPS the most when I am closer to the Base,
> than when I am say 25 miles or farther out. I know that the Military can
> degrade GPS for local areas, but I thought it was done the old way by
> turning SA on and off, on the satellites. Maybe they have some other
> capability and can do it in a small(er) area.
>
> Also, as anyone knows that has been near a US Military base recently is that
> they have four different threat levels. These threat levels among other
> things determine who has access to the bases. It has seemed to me that at
> the highest threat level, and occasionally at the second highest threat
> level are the times when this "SA" or what ever it really is, is turned on.
>
> Red