Addition of WiFi and LBS does NOT improve GPS Accuracy
Contrary to what some GPS tracker companies are stating the addition of wi-fi and LBS (GSM Masts) does NOT improve GPS accuracy.
According to the United States government civilian GPS has an accuracy of 4 metres RMS (7.8 metre 95% Confidence Interval) depending on conditions. GPS relies on accurately measuring the time it takes for radio waves to travel from different satellites to the receiver.
LBS and Wi-Fi location uses triangulation to determine the location, the accuracy depends on the number of GSM masts and/or wi-fi networks in close proximity. The state of art for Cell Tower based positioning is about 50 metres. This can be much greater in urban areas where there are fewer masts.
Our PawTrax devices use LBS and wi-fi to speed up the time it takes to get a location. It uses the location of masts and wi-fi networks as a means of telling the PawTrax device what GPS satellites to search for in a particular area rather than scanning for all of them.
Although LBS and wi-fi are both capable of giving a location in situations where GPS cannot (such as inside a building) we have chosen not to use these technologies when providing a location.
If your PawTrax device cannot get a GPS fix it will give the last known GPS location.
In theory it is possible for the PawTrax to give a location based on LBS or wi-fi, if GPS is not avaiable, but the chances are that this is not going to be very accurate and could possibly be 100's of metres out.