U.S. May Reduce Non-Military GPS Accuracy

ward99 writes "The U.S. government may be degrading GPS satellite signals, to cripple Iraqi forces' ability to use those systems during the war. This could potentially reduce accuracy from ~3 meters to over ~100 meters. Users depending on GPS systems may want to do sanity checks on any data returned by those systems during the war. The U.S. will do this by increasing the inaccuracies on the civilian C/A code, turning back on S/A (Selective Availability), by having the satellites deliberately and randomly return inaccurate information on where they are. S/A degrades GPS accuracy to only 100 meters 95 percent of the time and 300 meters the other 5 percent of the time. This will not effect the military P code."

Comments

Re:onstar?

[Lxy]

I've got a friend in MN. One winter night he and his buddies decided to have some fun with Onstar. Knowing that the call center is somewhere in Florida or California, they drove onto Mille Lacs lake (a very huge lake for those of you who don't know, it's larger than most counties). They called up Onstar to ask for directions:

Onstar: "hello?"

Friend: "We're lost. Can you help us find our way back?"

O: "Sure, hold on. Hmm.. this must not be working right. It says you're in the middle of a lake!"

F: "I know. We need to find our way back to shore"

O: "????"

F: "We're in Minnesota. There's ice on our lakes here"

O: "???? How are you in the middle of a lake?"

F: "We drove out on the ice"

O: "Why would you do that?"

F: "Ice fishing"

O: "?????"

F: "Can you direct us to the nearest landing?"

O: "Umm.. hang on a second. I need to get my supervisor."