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Discussion Starter · #1 · (Edited)
Garmin 500 not able to locate satellite

I bought a Garmin 500 a couple weeks ago and every time I turn it on it has problems locating the satellite. I then have to go into setup and pick the satellite. Yesterday, I used it for the first time on my bike and after about 9 minutes it shut off. I choose the US National satellite selection as I couldn't find a Canadian choice.

Any ideas on why it wouldn't be able to pick up satellite?
 

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Discussion Starter · #3 ·
I had the same problem, it would start loading the satellites, then just stop 1/4 of the way through searching for them. Brought it back and got a new one for free.
Well, that's disappointing. I bought the last one they had.
 

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I bought a Garmin 500 a couple weeks ago and every time I turn it on it has problems locating the satellite. I then have to go into setup and pick the satellite. Yesterday, I used it for the first time on my bike and after about 9 minutes it shut off. I choose the US National satellite selection as I couldn't find a Canadian choice. Any ideas on why it wouldn't be able to pick up satellite?
FWIW: It takes a minimum of 4 satellites to determine GPS position. AFAIK, Canada does not have a sat-nav system. There's US GPS and Russian GLONASS. EU and China are each working on their own sat-nav systems but they are not yet operational. I believe the 500 only receives GPS satellites whereas the newer X10 units may also have GLONASS receivers.

The satellites are not geosynchronous and continuously move across the sky. The Sat-nav receiver needs to have a table of which satellites are visible and other satellite specific data called an "almanac". This data is transmitted slowly to the receiver by the satellites. The receiver need to be on and in view of the satellites for some period (>15 minutes) in order to receive the full table the first time. After that, it uses the table and updates are made periodically while in use. Once your unit has acquired the almanac data and satellite lock, it should take only a minute or two to acquire lock the next time it is switched on, assuming you have not traveled 100 km or more since the last time you turned it on, in which case it has to discover which satellites are visible from its new location, which can take 5+minutes.

If your unit is not behaving like this, it may be defective. Spontaneously shutting off is certainly a problem/defect. Agree the Garmin forum is probably the best place to investigate this further.

https://forums.garmin.com/forumdisplay.php?219-Edge-500

If it's new and covered under warranty, Garmin will replace it. When I sent a 705 in, it took 1 week total time between mailing it priority mail and getting the replacement, but that was within the contiguous US.
 

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Discussion Starter · #6 ·
FWIW: It takes a minimum of 4 satellites to determine GPS position. AFAIK, Canada does not have a sat-nav system. There's US GPS and Russian GLONASS. EU and China are each working on their own sat-nav systems but they are not yet operational. I believe the 500 only receives GPS satellites whereas the newer X10 units may also have GLONASS receivers.

The satellites are not geosynchronous and continuously move across the sky. The Sat-nav receiver needs to have a table of which satellites are visible and other satellite specific data called an "almanac". This data is transmitted slowly to the receiver by the satellites. The receiver need to be on and in view of the satellites for some period (>15 minutes) in order to receive the full table the first time. After that, it uses the table and updates are made periodically while in use. Once your unit has acquired the almanac data and satellite lock, it should take only a minute or two to acquire lock the next time it is switched on, assuming you have not traveled 100 km or more since the last time you turned it on, in which case it has to discover which satellites are visible from its new location, which can take 5+minutes.

If your unit is not behaving like this, it may be defective. Spontaneously shutting off is certainly a problem/defect. Agree the Garmin forum is probably the best place to investigate this further.

https://forums.garmin.com/forumdisplay.php?219-Edge-500

If it's new and covered under warranty, Garmin will replace it. When I sent a 705 in, it took 1 week total time between mailing it priority mail and getting the replacement, but that was within the contiguous US.
I've never had it on for more than a few minutes since I purchased it, so I will take it outside tonight and leave it on for 20 minutes or so. Thanks.
 

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The WAAS satellites are Geosynchronous (these are the ones that show up as #33 and above).

As for the unit turning off after several minutes, it sounds like you didn't start the timer and thus the unit decided it should automatically power down.
 

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This is way off topic but I see people from other countries just constantly raging on the U.S. but they sure like to use our GPS system. I personally think we should charge them a fee and that money should be applied to our deficit. Several billions GPS users paying say $100 per year sounds like a good start.
 

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Discussion Starter · #9 ·
The WAAS satellites are Geosynchronous (these are the ones that show up as #33 and above).

As for the unit turning off after several minutes, it sounds like you didn't start the timer and thus the unit decided it should automatically power down.
But it wouldn't even get past "Locating Satellites".
 

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Discussion Starter · #10 ·
This is way off topic but I see people from other countries just constantly raging on the U.S. but they sure like to use our GPS system. I personally think we should charge them a fee and that money should be applied to our deficit. Several billions GPS users paying say $100 per year sounds like a good start.
How do you know that Canada doesn't pay a rental charge on US satellites? Maybe we don't want to pollute the galaxy with space junk, so we ask (very politely, of course) if we can share. You know, like car pooling.
 

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But it wouldn't even get past "Locating Satellites".
OK Obvious things first:
-GPS rarely works well on steep hillsides, in ravines, or especially indoors. Go outside in an open area. Specifically, north-facing slopes in the northern hemisphere will usually be unable to get WAAS reception so accuracy will be reduced.
-Your GPS receiver has to literally download positional data from each satellite to be able to make the necessary triangulation. this takes some time to load on the first time in a new area so if your GPS is new, put it outside, let it run, and it should work. The Edge 500 will cache this data and only refresh when needed.
-Navigate from the "Locating Satellites" screen to the Satellite Status screen to see if the unit is actually receiving any satellites at all.
 

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How do you know that Canada doesn't pay a rental charge on US satellites?
Because the GPS signals the public uses aren't encrypted. You don't use the satellites, you use their time signals. There are two GPS codes broadcasted by the satelites. The Coarse/Acquisition (C/A) code, which is freely available to the public, and the restricted Precision (P) code, usually reserved for military applications.

They'd first have to code the C/A signal, change every GPS device in existance, then charge fees for the encryption key. And of course... keep that key secret among the hundreds of GPS device manufacturers.
 

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Discussion Starter · #13 ·
OK Obvious things first:
-GPS rarely works well on steep hillsides, in ravines, or especially indoors. Go outside in an open area. Specifically, north-facing slopes in the northern hemisphere will usually be unable to get WAAS reception so accuracy will be reduced.
-Your GPS receiver has to literally download positional data from each satellite to be able to make the necessary triangulation. this takes some time to load on the first time in a new area so if your GPS is new, put it outside, let it run, and it should work. The Edge 500 will cache this data and only refresh when needed.
-Navigate from the "Locating Satellites" screen to the Satellite Status screen to see if the unit is actually receiving any satellites at all.
I'm going to try resetting the GPS and leaving it outside when I get home. The first time I did the set up, I didn't leave it on for very long.
 

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Discussion Starter · #14 ·
Because the GPS signals the public uses aren't encrypted. You don't use the satellites, you use their time signals. There are two GPS codes broadcasted by the satelites. The Coarse/Acquisition (C/A) code, which is freely available to the public, and the restricted Precision (P) code, usually reserved for military applications.

They'd first have to code the C/A signal, change every GPS device in existance, then charge fees for the encryption key. And of course... keep that key secret among the hundreds of GPS device manufacturers.
Now I'm going to feel guilty that I'm stealing from the US every time I ride my bike. :blush2:
 
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