John, it depends on a number of factors. GPS depending on the conditions may be less accurate than the ranges your discussing. Also, you're working with an older receiver that has by it's nature less accuracy. (luckally new receivers are extremely cheap) Also, if you're not receiving correction data that may play in to the calculations. Remember that corrected GPS can be as accurate as 0.5 meters and up but uncorrected GPS can be in the 100 meters range. (even 10 meters is outside the 25 feet example you gave) Also a factor are the number of birds you're receiving, the number of reflections and geography in your area and anything else that effects radio. As an example, I'm on the east coast right now. On the west coast (where I live) [picking up correction data is very easy. Here in the North East it's much more difficult (probably do more to my local surroundings and the lower angle in the sky of the platforms). Others can speak to the sindero specifics but in general it sounds to me like you're having signal issues of some form and you're working inside resolutions that would be tricky for non corrected GPS.
----- Original Message ----- From: "john Harden" <john.harden@xxxxxxxxxxxxx>
To: <gps-talkusers@xxxxxxxxxxxxx> Sent: Saturday, December 29, 2007 3:13 PM Subject: [gps-talkusers] Greetings and a question
Greetings, I am John Harden in Daytona Beach Florida. I purchased a used mPower QT 18 with Sendero GPS. I have version 4.02 and the Holux GPSLIM236 reciever.Now, this is a strange thing. When I am standing still and create a usert point of interest I am told that the point that I just created is somewhere else. Fore instance, I am told that the point that I just created is 25 feet south. If I haven't moved why is the point somewhere away from where I am?I have marked all the gates at our bus transfer station. While standing at gate N3 the GPS announced gates S4 and S7. S4 is not too far away but S7 is probably 200 feet down the platform and on the other side. This project is probably not going to be very helpful. Any help will be appreciated.John
