GPSrChive Discussion Forum

JungleJim wrote: Fri May 03, 2024 4:18 pm

Backstreetbob wrote: Fri May 03, 2024 6:20 am Also if you're walking straight up and down a mountain it works as it should, it's just any flat walking it can't seem to work it out correctly and seems to add any single change in elevation the altimeter makes as the altimeter fluctuates up and down even when still or on the flat..

I have observed the same behavior. The elevation reading is quite correct but sometimes it fluctuates one or two meters up or down when moving on level ground. The Total Ascent field seems to take all these small fluctuations into account.

For me I got the best results with Auto Calibration set to Off and manually calibrating elevation to a known elevation.

Yes it's really strange, you can be walking totally flat ground and the ascent or decent will just randomly jump up like 20 odd feet a time. Really hope this gets sorted as it really let's the device down...

just completed my usual 1.7 mile walk this morning. Tried the method with calibration OFF made zero difference. Once thing I have noticed is the Beidou satellites flash for a good 30mins + on a walk then they stop flashing when it's locked on. And when it does stop flashing I've noticed the ascent and descent stops randomly going up! I am wondering if beidou as something to do with it.. ?

I walked the route.
Values from the map for the prepared course: distance 13.9 km, ascent 162 m, descent 153 m.
Values from the received track record, interval 1 s, distance 14.88 km, ascent 179 m, descent 164 m. I went off course twice and had to go back, and the route on the map ended earlier, hence the differences in distance. The height profile appears to match reality. Especially since the embedded points in the planned course are 494 and in the completed course 5,500 points. Autocalibration altimeter settings - once.

Hi everyone I have just ran for the second time in a few weeks a regular 13 mile trail run that I do, for the second time now using my gpsmap67i with latest firmware ascent and descent figures have been pretty spot on, I would expect the ascent value to be around 1150-1250ft depending on some of the deviations that I sometimes take, prior to the firmware update my device was recording ascent values of 2600ft + today's recording 1224ft, so far 2 out of 2 I am happy with the results.
I have calibration set to once and always manually calibrate once before I start just using GPS elevation which is normally pretty spot on.

To be honest I do not really look at ascent and descent figures myself , I bought the unit to help with route navigation , accurate positioning, great battery and backup of in reach service when out of cell coverage , but happy with results the last couple of outings now.

I'd love to know how you guys are getting better results, went on a hike today up Black Hill, the 67 came back with 2067ft Ascent and 2023 descent, on Garmin Connect with elevation corrections turned on it gives 1584 ft ascent and 1589ft decent.

My epix recorded 1611ft ascent and 1593ft decent
65s recorded 1660ft ascent and 1676ft ascent much more inline with the elevation corrections and each other!

The 67 was still miles off! All though it doesn't perform as badly when hill/mountain walking as oppose to on the flat around streets. But still not accurate enough.

The 67 was set to Calibrate ONCE and I manually calibrated at the start of the activity the known height.

Did my usual walk again today, and ascent was again more than it should be, 59m while couple of meters is expected. So different result than two earlier tests on 8.30.

And as Backstreetbob mentioned earlier it took quite some time before the BeiDou satellites got a good fix, I didn't time exactly but I think 30 minutes. At the start I only got fix on two BeiDou satellites.

Also at some point in the walk, after about 30 mins, the ascent value stopped going up constantly and was much closer to expected ascent for the rest of the walk.

Anyone else seeing the same?

JungleJim wrote: Tue May 07, 2024 6:34 pm 30 minutes

My receiver was on much earlier.

For those potential correlating the issue to BeiDou satellite availability, please repeat same tests but with GPS only configured on the device.

Nail wrote: Tue May 07, 2024 6:47 pm

JungleJim wrote: Tue May 07, 2024 6:34 pm 30 minutes

My receiver was on much earlier.

Yeah, I don't think it took so long every time I have used my unit since updating to 8.30. But also didn't closely look at it, so I'll check next times I use my GPSMAP.

JungleJim wrote: Tue May 07, 2024 7:39 pm

Nail wrote: Tue May 07, 2024 6:47 pm

JungleJim wrote: Tue May 07, 2024 6:34 pm 30 minutes

My receiver was on much earlier.

Yeah, I don't think it took so long every time I have used my unit since updating to 8.30. But also didn't closely look at it, so I'll check next times I use my GPSMAP.

And what does the data look like in the track after removing statistical data?