GPSMAP 65 no longer persists GPS almanac / nav data.

[Zoot]

So, for the first month or so that I've had the GPSMAP 65 (updated to 4.50), it has generally performed very well (apart from not working as a serial device over USB per my other post) and when I would turn it on after being off for a day or so, by the time it started up all the way it would already have almost all-in-view sats from all three constellations locked and showing a 6ft solution. This was quite impressive!

Now, *possibly* related to simply having plugged it into a different PC as part of testing the serial issue, it no longer seems to remember even the almanac and it goes into a cold start on every power up! Even if I simply power it off and on it will have all the GPS sats blinking which it re-downloads the nav messages (though it did briefly hang onto the GPS almanac there it seems) but GLONAS goes into pure coldstart mode and has to discover everything from scratch, and it takes like five minutes before it even TRIES to start looking for Galileo sats! Eventually it finds everything again, but it means a substantial delay before you have the best solution available.

Super ultra frustrating. Has anyone seen this particular behavior? I guess I will try some reset procedures.

[ewald.gruen]

Both my 65s (4.50) and my 66sr (5.50) seem to lose the Galileo and Glonass satellite ephemerides every time I reboot, which was never the case with my 64s.

And the reacquisition of Galileo or Glonass satellites after a reboot usually takes minutes for both (at least without a CPE.BIN on either device).

[Zoot]

I tried Reset All Settings with no apparent effect. I then removed the batteries and let it sit for 24 hours on the off chance that might affect it. I then powered it up and it started discovering the GPS constellation from scratch. I went for a hike for an hour outdoors with it hanging from my belt. It was a full 50 minutes before it even *started* trying to find the Galileo sats, and took 5-10 minutes to get to 4-5 sats which were no longer blinking there.

After that, I can now power it off and on and it's back to almost instant acquisition of all three GNSS including Galileo with no problems.

I have no idea whether anything I did had an effect on "fixing" it, but it's back to performing as expected.

For now anyway

[GPSrChive]

As the GPSMAP 66sr and GPSMAP 65s are the first Multi-Band Garmin handheld devices, I have no doubt there will be many software updates for the GNSS chip inside these models yet to come.

[ewald.gruen]

@Zoot, I don't know if this is helpful for your use case, but Galileo and Glonass satellite acquisition is almost instantaneous on both the 65s and 66sr if there is a current CPE.BIN on the device.

As the GPSMAP 66sr and GPSMAP 65s are the first Multi-Band Garmin handheld devices

Yes, but that is no excuse for such flaws in the main functionality of the device - almost two years after the product's launch. If I remember correctly the 64s also was one of the first handheld devices with Glonass support and I bought it a few weeks after it was released and didn't upgrade the firmware until a few days ago. Why? Because it simply worked.

[GPSrChive]

The eTrex x0, released in 2011, was the first Garmin outdoor handheld with GLONASS support. The GPSMAP 64 series was announced three years later, in 2014, and so already had a minimum of three years GLONASS development time at launch.