Satellite Fix very slow!

Discussion related to the Garmin Oregon 7x0 series GPSr
Plato
Posts: 35
Joined: Sat Jun 17, 2017 3:58 pm

Satellite Fix very slow!

Unread post by Plato »

As I mentioned in my other post (7 weeks hike) getting a satellite fix takes a lot of time on the Oregon 700. Even under good conditions (open sky around me) it oftyen takes 2 minutes and I don't think that's normal. Even a warm fix often keeps me waiting very long. My unit is never connected to the internet so no A-GPS for me, just like the 600.

The past two weeks I've been searching other forums on this matter and it appears that others are reporting the same problem with their 7x0, 2 minutes for a fix is very common. I thought my Oregon 600 was slow on getting a fix but the 700 is much worse!

I am suspecting a hardware/software problem with the 7x0 series.
User avatar
GPSrChive
Site Admin
Posts: 3881
Joined: Fri Jan 20, 2017 11:29 pm

Re: Satellite Fix very slow!

Unread post by GPSrChive »

How long has the unit been off before turning it on again and having the long wait for a satellite Fix?

How far is it from the last location it had a fix?

What firmware version?
Plato
Posts: 35
Joined: Sat Jun 17, 2017 3:58 pm

Re: Satellite Fix very slow!

Unread post by Plato »

I am experiencing long fix times in all kind of situations. I find it normal to wait long if the unit has been off for several days and the location changed as well.
I don't think it's normal that it takes two minutes to get a fix again after 10 minutes off on the same location.

I had this problem often on my 7 weeks hike in the Pyrenees with firmware version 3.30 and now with v3.60.
User avatar
GPSrChive
Site Admin
Posts: 3881
Joined: Fri Jan 20, 2017 11:29 pm

Re: Satellite Fix very slow!

Unread post by GPSrChive »

Thanks for the additional info. I have not experienced this behavior with my 750t, which has been off for more than a week right now, and when I just booted it up, it had satellite lock (22ft) by the time I could open the Satellite application, which was less than a minute after initially pressing the power button. I am also at firmware 3.60. I will keep this in mind as I use it to see if I can observe similar behavior.
User avatar
GPSrChive
Site Admin
Posts: 3881
Joined: Fri Jan 20, 2017 11:29 pm

Re: Satellite Fix very slow!

Unread post by GPSrChive »

BTW, can you link your Oregon 7x0 to the internet using a smartphone to see if that mitigates the issue, as a testing exercise?
Plato
Posts: 35
Joined: Sat Jun 17, 2017 3:58 pm

Re: Satellite Fix very slow!

Unread post by Plato »

Actually I am waiting for EddyG to joint this discussion, on forum.gps.nl there is a similar discussion and he did a very nice test with 6 GPS receivers he owns. Thanks EddyG!

Here are his results:

Image

The Dutch discussion:

http://forum.gps.nl/viewtopic.php?f=136&t=49525
Plato
Posts: 35
Joined: Sat Jun 17, 2017 3:58 pm

Re: Satellite Fix very slow!

Unread post by Plato »

Garmin is rolling out firmware updates for many outdoor devices at the moment.
They all address only one problem: Fixed potential GPS issue.

Let's hope this is the solution to the inconsistent fix-times I have with my 700

I did some testing yesterday and they show very inconsistent results:

Firmware v3.60 and GPS only (no GLONASS and no WAAS/EGNOS)
First I activated Wifi, went into my garden and got a fast cold fix, it took about 30 sec after the Homescreen appeared.
Later during the day I did several cold fixes again but now without Wifi. The first attempt took 5 minutes! The Satellites app showed all 12 bars, totally black for minutes, only the satellite numbers were changing but no signals within the bars. Finally all bars disappear (all at the same time) and one after each other pops up again showing signal strengts and a minute later i got a fix. Conditions in my garden are not bad, no high buildings around and a clear view to the sky around me.
This is exactly the behaviour I had many times during my 7 weeks hike in the Pyrenees.

All other cold fixes after this one went smooth and within a minute. I never have the experience that a fix is already there before I could hit the Satellites page!
There is a clear difference between the good and the bad fix-times:
  • A fast fix never starts with all 12 Satellite bars totally black, they appear one by one and show reception immediately.
  • A slow fix always starts with all 12 Satellite bars black as described above
Plato
Posts: 35
Joined: Sat Jun 17, 2017 3:58 pm

Re: Satellite Fix very slow!

Unread post by Plato »

Two years later and still eperiencing slow gps-fixes (firmware 4.70).

This summer I walked 960km through the Italian Alps (the GTA) with my Oregon 700 and yet again I experienced many slow gps-fixes, even when I had a fix 10 minutes ago, turned off my Oregon and restarted it 10 min. later. Exactly the same behaviour as two years ago in the Pyrenees.

I discovered something that raises some questions however (see screenshots):
The satellites-page often shows 12 black blocks for 30-60 seconds, before showing some reception and finally gets a fix. This can take 1-2 minutes.
If I tap 'AutoLocate Position' in the menu I get 'Locating Satellites' immediately and the fix is much faster!

Question: To get a fix faster I always had to manually 'force' it in the menu, why doesn't my Oregon AutoLocate it's position automatically?

Satellites.jpg
You do not have the required permissions to view the files attached to this post.
User avatar
GPSrChive
Site Admin
Posts: 3881
Joined: Fri Jan 20, 2017 11:29 pm

Re: Satellite Fix very slow!

Unread post by GPSrChive »

Re: Your most recent question

Autolocate - Search the sky

The final method used by your Garmin enables it to find itself and get a lock completely without any outside help. In autolocate mode the unit does not use the internal almanac data but instead just uses brute force techniques to find the satellites. On any of the older multiplex receivers this can take 7.5 minutes to 15 minutes with a clear view of the sky for it to gather enough data to acquire a 2D fix. On the 12 channel parallel units the time has been reduced considerably since much of the data can be gathered simultaneously using the 12 channels. A 3D fix under these conditions can usually be obtained in about 3 to 5 minutes. Note that while a fix may be obtained, this is not sufficient time to reload the full almanac. The almanac requires 12.5 minutes to download from the satellites. For this reason, if you have to do an autolocate you should continue to leave the unit on while it regathers its full almanac, or you may have a similar problem the next time you turn it on.
Plato
Posts: 35
Joined: Sat Jun 17, 2017 3:58 pm

Re: Satellite Fix very slow!

Unread post by Plato »

Thanks, I didn't know that but 3-5 minutes is not what I see.
I immediately went outside, switched on my Oregon, hit the satellites page and then forced AtoLocate Satellites in the menu. I had a 3D fix within 24 seconds.
I did this hundreds of times in the Alpes and had the same experience everytime, if I waited for the unit by itself to get a fix it took much longer.
Post Reply

Return to “Oregon 7x0”