Locking on Satilites

 

Having traveled to Colorado for a few weeks from CA, I notice that the locking up time on my NUVI is much longer. Any reason why and the first time?
JRO

Lock on

If you travel over 500 miles before turning on your unit it will take as much as 5 minutes to lock on. After that it shouldn't take any longer unless the view of the sky is obscured by mountains, trees, etc.

I've noticed...

I've noticed that sometimes if it has been a few days since last using my Nuvi 650, that it will take unusually long to establish the first lock. Just yesterday I turned it on and it took at least 5 minutes to connect. I hadn't used it in more than a week and I turned it off about 12 miles from where I turned it back on. But the 12 miles probably isn't significant to discussion, I don't think.

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--- GPSmap 60CS, Nuvi 650 & Nuvi 1490T---

Guessing it's the time

Guessing it's the time between turn-ons that caused it to take longer. I'm always surprised how long it takes. Amazingly, if I drive to lunch while at work, I can get two very fast lock-on's. If I leave my car sitting during the day (without driving to lunch), then it takes a minute @ the end of the day to get a lock (as opposed to 15 seconds).

Start-up times

Quick starts are guessing that you haven't moved a lot from where you were when the last good GPS fix was obtained, the almanac data (used to calculate satellite positions) is still current, and the internal clock is pretty accurate.

I don't know what the time limits are in the Garmin products, but I'd guess they're around 6 hours or so -- I see the same thing, drive somewhere at lunch and get quick startup at lunch and when I go home, but if I don't go anywhere at lunch, it takes longer to acquire a set of birds when I leave for home.

Similarly, it takes longer for it to wake up in the morning -- just like me! It doesn't help matters that I'm driving around, making turns, and confusing the little beast by not letting it see the same part of the sky for very long. Some times it doesn't acquire a good set of satellites until I've been sitting at a red light for a while, or on a straight section of freeway with nothing to occlude the sky.

A test I could perform would be to just sit in the driveway in the morning and see how long it takes before it's happy, and compare that to the time it takes if I just take off and head for the salt mines.

As has been mentioned, a great way to get a GPS to go off and sulk for a while is to turn it off, move it a few hundred miles, then turn it on again. Most modern products will at least retain the almanac data, search the sky for satellites, and compute a first fix. An early Trimble product I had would throw away the almanac data, going back to a cold start, which took many (many!) minutes if you were sitting still.

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Nuvi 2460, 680, DATUM Tymserve 2100, Trimble Thunderbolt, Ham radio, Macintosh, Linux, Windows

locking on satellites

I find that it takes a long time to lock into satellites when I haven't used the GPS in a while.