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When you let it sit for a long time or when you've moved very far since the last time it was used, that predictive algorithm doesn't help, so it has to check each satellite and figure the position from scratch. So if you fire it up again the very next day from the same spot, it will lock on faster because it has a rough idea of which satellites it should be looking for and where it is. The systems use predictive positioning based on an internal clock. Essentially, the unit doesn't have to "remember" a rough position, because it always "knows" the rough position from cell tower signals.Īt least, that's my theory for why cell phones lock on faster based on my understanding of how the predictive algorithms are used to speed GPS acquisition in Garmin units. This is why it's much faster if you're turning the unit on near the same place where it was turned off.Ĭell phones can get rough location from the cell towers (within a couple km), which, if combined with good good enough programming, can be used to approximate the spot and speed GPS acquisition. Easily share your publications and get them in front of Issuu’s. Click to expand.The systems use predictive positioning based on an internal clock. I have had a Garmin Streetpilot 2620 for 7 or 8 years and it took me everywhere without a problem. Issuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online.