Acquiring Satellites, Awaiting Satellite Signal, The GPS signal was lost x seconds ago… This is the time of year when we start getting lots of questions about this message with people frustrated that their GPS “doesn’t work”. So what does this error message mean, and what (if anything) can you do to your GPS to make it get a signal faster?
In order to determine your location, a GPS needs to listen to the network of GPS satellites. In order to listen to the satellites, it helps if the GPS can predict “where” to listen for the signal. And in order to know where to listen, it helps to know where you are…. a nice little catch-22. (I’m oversimplifying things a bit for the sake of not conducting a physics class when people just want their GPS to work.)
So how do you get around this catch-22?
Tips for New GPS Devices
- Make Sure the GPS has a good, clear view of the sky. “Clear” does not need to be sunny. Overcast skies have no noticeable impact on GPS performance. But buildings and trees do. So take the GPS outside where you have the biggest sky view as you can.
- Next, wait for the GPS to acquire a signal. If this is the first time you have used it, expect it to take up to 20 minutes to find a signal. Most often it will take less, but prepare for 20 minute. Now for an important step… Once it has found your location, let it continue to sit there for about 30 minutes.
While the GPS is turned on with a signal, it is downloading “almanac” data from the satellites. This information will help it find the satellites much, much faster in the future because it will be better able to predict where to listen for the satellites.
It is important that while the GPS is acquiring a signal that you not move the GPS. A few feet is fine, however if you start driving with the GPS before it has locked into a signal, it will take much, much longer to acquire a signal, if it finds one at all.
Other Signal Impacts
Rural areas don’t make a difference like they do with devices that rely on terrestrial signals like mobile phones. The GPS system was designed to work nearly any place on Earth. In fact, urban areas with tall buildings nearby are the toughest challenges for GPS systems.
GPS manufacturers are constantly working on ways to improve their products, and acquiring GPS reception is no exception. So check if there are any software updates available for your GPS. Some GPS manufacturers like TomTom also offer updates on a periodic basis that help it with that “almanac” data. TomTom calls this “QuickFix” updates and you can download them to your GPS to help it find a signal faster.
Some types of windshields (specifically athermic windshields) don’t allow the GPS signal to pass through as easily. In this case, an external antenna can help if one is available for your GPS. If you live in urban area with lots of tall buildings, an external antenna can help in that situation as well.
Taking a trip?
Note that if you move the GPS a good distance from where it was last used (say more than 100 miles) it will take longer time to initially acquire a signal. If you fly somewhere for vacation and take your GPS with you in the rental car be ready for a double whammy. Not only will it take longer to acquire a signal because the GPS has moved a large distance since it was last turned on, but you will often start at the airport in a parking garage where you don’t have an unobstructed sky view to listen in to the GPS signal.
And if you are going on a trip you might want to check out our tips on traveling through airports with GPS where we discuss x-ray machines and other transportation tips.