fails to "acquire satellites"

Discussion in 'GPS 101 - Which GPS For Me' started by Motoswami, Aug 27, 2012.

  1. Motoswami

    Motoswami Motoswami

    Joined:
    Mar 10, 2006
    Oddometer:
    93
    Location:
    northeast Georgia
    My Zumo 550 has, since new, occasionally on start-up taken a very long time (3-5 minutes) to figure out how to connect with the heavens. It simply sits showing the map of where it last shut down with the words "Acquiring Satellites" across the screen's top and a question mark flashing in the center where the motorcycle icon normally resides..

    Eventually, it goes, "Ah Ahah!" and goes on about its business, the motorcycle icon appears (actually, I use the plain triangle because it's impossible to tell at a glance which is the front and which is the ass-end of the corny motorcycle icon), and the GPS starts working like an, well, GPS.

    Sometimes it is necessary to take a pop quiz, and various questions appear (fortunately, the answers are usually simple "yes/No" but you gotta answer correctly) asking about location and date. Normally, once these questions have been satisfied, the GPS goes into normal function rather quickly.

    Last night headed from the country into metro Atlanta, the unit was working fine. I stopped and shut down right in the middle of the city, and then an hour later powered the GPS back on. It took what seemed forever to finally acquire satellites, but finally in about 10 minutes, and three questions, figured things out and began properly functioning. I reached the evening's destination and made the mistake of powering off (running from a cigarette lighter plug in the car) and did not ask the unit to continue on battery while I watched a movie. Two hours later, movie ended, I started up the car and the GPS informed me it was "acquiring satellites." This time, it took the unit a good 30 minutes to connect with the satellites and it ran fine the last hour of my trip home.

    There was some cloud cover but nothing unusual. The failure was not just when I was between tall skyscrapers and high-rise buildings but also in single-story residential areas.

    Anyone else had this problem? Can anything be done thru Garmin's web site as in maybe (Download a "fix" via a USB cable hook up between unit and computer?
    #1
  2. Buzzbomber

    Buzzbomber Not Dr. Who...

    Joined:
    Oct 30, 2008
    Oddometer:
    1,290
    Location:
    Betwixt Heaven and Hell, Skylands of NJ
    I have had the same issue repeatedly, albeit with a TOTALLY different model, which probably negates any utility to my posting about it here. FWIW, I have a NUVI 200W (ancient now, I know) that has behaved similarly since essentially new. It's happened in parking garages, suburbia, and the middle of hay fields - sky view doesn't seem to be a factor. I have noticed that the unit's temporary disorientation is much worse if I power it up someplace other than where it was last shut down, and that it's usually quicker to shut it off totally for ~1 minute and reboot than to wait for it get it's bearings if it's being stupid. Other than that, :dunno

    I know that probably doesn't help, but hey, at least you're not alone:lol3
    #2
  3. Motoswami

    Motoswami Motoswami

    Joined:
    Mar 10, 2006
    Oddometer:
    93
    Location:
    northeast Georgia
    Hey Buzz:

    I appreciate your response. Knowing that the disorientation can occur even on different Garmins is good to know. With the problem spread amongst the model line, perhaps Garmin techies will be motivated to look for a solution.

    I'll try turning it off for a longer period next time. Too bad the Zumo requires a micro-allen wrench to pop out the battery for a total re-boot. Usually too much trouble, but worth it perhaps if in a strange city and totally lost.

    Pete
    #3
  4. abhibeckert

    abhibeckert Long timer

    Joined:
    Feb 15, 2010
    Oddometer:
    1,757
    Location:
    Cairns, Australia
    The satellites take about 12 minutes to send enough data for your GPS to figure out where you are in the world. And that assumes you pick up their signal perfectly, which is often not the case (it's a weak radio signal, going over a very long distance, bouncing off trees and buildings and stuff).

    GPS is great for telling you that you have moved 3m to the south in the last quarter of a second, but it is not very good at figuring out what your location is if you have no starting point. When you turn the GPS off, and turn the GPS on again without moving it very far (eg, still inside the same city) it should get a fix pretty quickly (assuming you have a strong signal), but it doesn't always happen.

    Any time your GPS takes less than 20 minutes to figure out where you are, you should consider yourself lucky, because the "garmin techies" have done their job using all kinds of weird and wonderful techniques to guess your location without having enough data to actually figure it out.

    GPS-equipped mobile phones use the cell tower network to figure out where you are within a mile or so, and once they know that they only need a few seconds of GPS data to narrow the position down to a few meters. WiFi can also be used in the same way, though not as reliably. This is called A-GPS.
    #4