GPSMAP65s - Galileo Satellites Flashing [Bug 8]

[pokyyy]

My new 65s has 4.00 version but Galileo is not showing at all but it worked to begin with. I need more time with it to be certain. GPS and GNSS seem OK at present.
I will report back.

[pokyyy]

Update

I tried my new 65s (firmware 4.00) properly today:
GPS L1 and L5- one satellite flashed for less than a minute at the beginning and then fixed
Galileo E1 and E5- no satellite flashing
Glonass L1- no satellite flashing
Accuracy: 1.8 m

Isn't there supposed to be a L5 band for Glonass? Anyway, it seems the new firmware is working fine so far.

I am happy with the device so far, for my purpose. I just wish the screen had slightly more contrast.

[GPSrChive]

The GLONASS constellation only provides L1 band signals at this time.

See GPSrChive > GPSMAP 65 > Pages > Satellite for additional information.

[skinnie]

Update

I tried my new 65s (firmware 4.00) properly today:
GPS L1 and L5- one satellite flashed for less than a minute at the beginning and then fixed
Galileo E1 and E5- no satellite flashing
Glonass L1- no satellite flashing
Accuracy: 1.8 m

Isn't there supposed to be a L5 band for Glonass? Anyway, it seems the new firmware is working fine so far.

I am happy with the device so far, for my purpose. I just wish the screen had slightly more contrast.

Can't find that firmware on garmin website. Any hint were to get it ?
Garmin express doesn't find any update on mine.

[GPSrChive]

Garmin have not yet published 4.00.

[mrfreeze]

I did some further tests. When I went for a walk at the beginning I had 7 satellites from GPS, 6 Galileo (3 flashing) and 6 Glonas. After 2 hours most of the Galileo and Glonas satellites disappeared. Only 1 Galileo and 2 Glonas were visible. I've switched gps off and switched it on again. No difference. I switched the device completely off and on again. There were 6 Galileo and 7 Glonas after a few seconds. For the next 30 minutes 3 of the galileo never stopped flashing. GPS and Glonas worked as expected. After 30 minutes I've switched the device off because I've arrived at my home.
Today I've tested the 65s in the mountains for the first time. A much more difficult situation for the device than near my home. A few times the accuracy went from 1.8 metres to 2 metres. I went for about 7 hours. I always had 6 Galileo and 5 Glonas. GPS worked normal as always. None of the satellites flashed.
Maybe it's a feature that the 65s will search for satellites in all available systems directly after switching on the device. To get an exact position as fast as possible. But when GPS is working fine the device stops searching for satellites in Galileo and Glonas. Only when GPS is not precise enough it'll search for other satellites again. Maybe the device safes energy with that feature. That would explain why satellites disappear near my home. But not in the mountains.
Can anyone verify that?

[pokyyy]

@mrfreeze

I thought that was the whole point of being multiband i.e. use all the satellites available to increase accuracy. It doesn't make sense to use just the GPS if multiband has been selected in the device menu.
I haven't tried mine in difficult conditions or as long as you yet. I just hope this new firmware has resolved the problem.

[mrfreeze]

@mrfreeze

I thought that was the whole point of being multiband i.e. use all the satellites available to increase accuracy. It doesn't make sense to use just the GPS if multiband has been selected in the device menu.
I haven't tried mine in difficult conditions or as long as you yet. I just hope this new firmware has resolved the problem.

I'm not an engineer or developer of the device. But it consumes more energy while searching satellites in all systems. And they decided that an accuracy of 1.8 meters is the best. And the energy consumption is it not worth to get precision like 1.5 meters. Because on the other hand you also want to have a long battery lifetime. In difficult situations the device is searching for satellites in other systems to get the accuracy of 1.8 meters again. It's a tradeoff.
The possibility to activate only GPS also makes sense. Because often you don't need highest accuracy but longer battery lifetime.
But that's only a theory. It really would be interesting if others can see the same behavior.
Of course Garmin should give a hint if that's really a feature. Like a message in the display with the Galileo or Glonas satellites. Or it's a bug and they have to change that behavior.
I also have to do more test to reproduce that.

[pokyyy]

Of course Garmin should give a hint if that's really a feature. Like a message in the display with the Galileo or Glonas satellites. Or it's a bug and they have to change that behavior.

That would be ideal but I doubt Garmin would do it.

If the best accuracy is 1.8m regardless of whichever satellite, I will be happy with that. I read somewhere that the accuracy could be as good as 1m but I don't know if that has been verified or any statement released by Garmin with regards to that.

[GPSrChive]

Let us not forget, the GPSr only needs four usable signals to trilaterate its location.

Some of the very early consumer devices were only equipped withn 4 channels for this reason. Upgraded units would eventually see 8 and then 12 channel chips. These, and all future Garmin consumer grade GPSr only use the 'best signals' available when calculating thier position.

When GLONASS was introduced with the eTrex x0 series this was bumped to 24 channels.

The most recent Multi-Band + Multi-GNSS models now have 48 channel receivers.

But they still only need 4 usable signals to determine your location.