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View Full Version : where am I ?



dougreed
2005-Jun-01, 04:40 AM
HELP, I don't know where I am! :( ... I do not own a GPS device, however, recently I saw a GPS (Garmin) instrument that was stationary that was in a constant state of locating itself :blink: . Why would a stationary device keep changing it's geographic location as well as altitude? The longitude, latitude and altitude was in constant change-although it was only by a few feet/yards in any direction. Is that normal? :huh: ...see-ya, dougreed

piersdad
2005-Jun-01, 07:49 AM
Im not familiar with the tech side of GPS but if they depend on a line of sight EM wave then they could all be bent as they pass through the earths atmosphere and thus the slight bending would shorten of lengthen your precise distance to each of the positioning satelites.

Matthew
2005-Jun-01, 09:42 AM
Using the GPS system you can get to pretty precise measurments of your location. If the object you speak of dougreed kept on updating its location to change a few feet the GPS system must have been accurate to only a few feet. Which is pretty good considering. Howver there are of course ways to improve the GPS system using more complex equations to calculate position, and better sensors to track the signal coming from the three required satellites you can get down to an accuracy of only a few cm (or 1-2 inches).

astromark
2005-Jun-01, 10:49 AM
All of the reply's are on target. The GPS you saw might have been serching for the best signal strength. I was recently with friends who had one of these things. At one time it was reading from seven satalites. The position it was conferming was within meters of all of them. Very pricise. The next generation cell phone will have the basic function built in.
Where am I? go to your letters tray, read one. Thats where you are.