"Static navigation"

Ytterligare en anledning till att det verkar väldigt hoppig i början av promenaden kan vara att GPS-chipet som är ett SiRFStar III tillämpar något som kallas "static navigation". Det här kan man läsa:

"The new chipset also features a different approach to the usage of the actual satellite signal. Where standard receivers require a signal strength of at least 28 dB to even consider a satellite for correlation the SiRFstarIII chipset will basically use any signal it can get, down to 13 dB. Thanks to its 20 channel receiver it will also be able to use signals that are bouncing off buildings (especially in urban canyons, but also indoors) and include them into the correlation. This approach of course also comes at a price. If you use such low signal levels, you will also get some pretty bad signals that will make your position jump around quite a bit when you are stationary or moving slowly. SiRF's answer against that is called “Static Navigation” and it is a feature of the chipset that freezes your position when you are moving slower than 4 km/h . Position changes will only be registered when the difference exceeds 50 meters. As a result when you walk slowly your position seems to be frozen and it updates only every once in a while."

Men det största problemet verkar ligga i att enheten inte lyckats bestämma positionen mot nog många satelliter. En lösning skulle kunna vara att inte tillåta loggning innan nog många satelliter dykt upp men det känns inte prioriterat.

Citatet är taget ifrån: www.pocketgpsworld.com/bt338.php