Garmin H series trip computer - another take

[jmundinger]

As part of the on-going conversation that we have been having concerning the discrepancy between the odometer and the track log that seems to occur with the H series Garmin eTrex units, I should add this one to the mix.

 

I sent Garmin tech support an email in which I indicated that I had performed the update; described the erratic behavior that I had observed with the speedometer/odometer while hiking; and, provided the odometer and track log data.

 

I received the following response:

 

Thank you for contacting Garmin International,

 

I would suggest performing an auto locate on your unit.

 

1. Press the menu key (button on the left hand side of your unit) from

the satellites page and select use with GPS off.

 

2. Press the menu key again and scroll down and select new location,

then select automatic.

 

3. Take the unit outside, let it set stationary for 25 minutes to

acquire the necessary almanac data.

 

I'm trying it because that is what he suggested, but I sure don't understand how that solution equates with the problem.

[Benthic2]

I have missed the previous discussion on the issue, but if the odometer is showing a greater distance than the track log, it may be that the odometer is taking continuous data while the track log is setmented from point to point. In other words your track log is a series of straight lines from data point to data point but the odometer is a continuous and curvy line that was your actual path. If you went in a circle your odometer would show the circumference of the circle, while your track long might show an octagon. ( that's kind of an extreme example to illustrate my point...you'd have to be going really fast to get a result like that )

[jmundinger]

The problem is the opposite, i.e. the odometer is showing a decided shorter trip than the track log. The speedometer behaves erratically when moving at slow speeds (somewhere around 2 mph - not an unusual speed when hiking). When the speedometer quits recording, the clock for moving time stops and the odometer quits recording - resulting in the discrepancy. Based on the track logs that I have downloaded to quad maps, the track log seems to be correct.

[+GPSlug]

I'm trying it because that is what he suggested, but I sure don't understand how that solution equates with the problem.

Your understanding is correct. That's got to be a canned answer they use when they have nothing else.

[jmundinger]

Your understanding is correct. That's got to be a canned answer they use when they have nothing else.

 

I'm more interested in getting to the bottom of this issue than I am in busting on Garmin.

 

I shared the post for three reasons:

 

1. This topic has gotten some attention on this board and this was a new piece in the puzzle.

2. Perhaps someone who knows something more about this technology than I (it wouldn't take much) could offer some explanation.

3. Share the suggestion with others in case they wanted to try it and then discuss the results.

 

I also sent Garmin a follow up, more or less the same thing that I said in here. I received the following reply:

 

Distance and speed are almanac data based, the auto locate may help your

issue, keep me informed.

 

It only cost 30 minutes of battery life to try this suggestion. If it works, great. If it doesn't, I'll have more information to share with Garmin as they continue to work on the issue. And, if this really is the solution and I didn't try it, I'd feel pretty foolish.

[fujitsu]

jmundinger,

 

Thank you to share this information with us. Tell us, if you don't mind, your results. I hope I could try it this weekend. We never know...

 

regards

António

[BelchFire]

Your understanding is correct. That's got to be a canned answer they use when they have nothing else.

 

I'm more interested in getting to the bottom of this issue than I am in busting on Garmin.

 

I shared the post for three reasons:

 

1. This topic has gotten some attention on this board and this was a new piece in the puzzle.

2. Perhaps someone who knows something more about this technology than I (it wouldn't take much) could offer some explanation.

3. Share the suggestion with others in case they wanted to try it and then discuss the results.

 

I also sent Garmin a follow up, more or less the same thing that I said in here. I received the following reply:

 

Distance and speed are almanac data based, the auto locate may help your

issue, keep me informed.

 

It only cost 30 minutes of battery life to try this suggestion. If it works, great. If it doesn't, I'll have more information to share with Garmin as they continue to work on the issue. And, if this really is the solution and I didn't try it, I'd feel pretty foolish.

Did you do it, and did you notice any changes in track log or odometer recordings?

[jmundinger]

Did you do it, and did you notice any changes in track log or odometer recordings?

 

I did it, but it might be a few days before I have the time for a hike that would really put it to the test. I will post results when I do.

 

I was hoping that someone else might try it as well.

[freeday]

...

 

1. Press the menu key (button on the left hand side of your unit) from

the satellites page and select use with GPS off.

 

2. Press the menu key again and scroll down and select new location,

then select automatic.

 

3. Take the unit outside, let it set stationary for 25 minutes to

acquire the necessary almanac data.

...

1 - OK

2 - OK

3 - 3D-Fix after 30 seconds - HCX and CSX

 

So i am not shure if waiting for 25 min is necessary

 

This procedure seems to be different to a hard reset (with a NEW loading from almanach)

Edited October 13, 2007 by freeday

[Forkeye]

I have found that talking to Garmin techs about a GPS problem is useless.They will always try to blame it on your location,the weather something you must of done,they will never admit that it is a known problem,and say we are working on it and there will be a software release shortly.I have asked about things that were never mentioned in their operation mannuals about the unit, and still only gotten vague awnsers.If Garmin doesnt know how they work then who does???.Having worked in the electronics industry for years,and having done many software updates to many pieces of equipment,often screwing up more issues than fixing issues,I am reluctant to try any new software if I cannot revert back to the old.

[freeday]

I did Point 1-3 (but 3. only with 5 minutes, because there was a 3d-fix after 30 seconds) -> the result:

 

saved track:

1.28 km saved track exactly the same on both systems !!

 

odometer:

vistaHCX 870 meters gpsmap60csx 1300 meters

 

[John E Cache]

I did Point 1-3 (but 3. only with 5 minutes, because there was a 3d-fix after 30 seconds) -> the result:

 

saved track:

1.28 km saved track exactly the same on both systems !!

 

odometer:

vistaHCX 870 meters gpsmap60csx 1300 meters

 

Total time 26+ minutes.

HCX stopped 13min moving 13min

CSX stopped 3min moving 23min

 

Are they both wrong? Did you stop at all? My guess has always been that all GPS odometers are bad.

[freeday]

...

Total time 26+ minutes.

HCX stopped 13min moving 13min

CSX stopped 3min moving 23min

 

Are they both wrong? Did you stop at all? My guess has always been that all GPS odometers are bad.

The gpsmap60csx-odometer is fine.

You can see

moving time (the gps believes you are moving)

stopped (the gps believes you are NOT moving)

 

The best value is the "saved track" value.

[John E Cache]

...

Total time 26+ minutes.

HCX stopped 13min moving 13min

CSX stopped 3min moving 23min

 

Are they both wrong? Did you stop at all? My guess has always been that all GPS odometers are bad.

The gpsmap60csx-odometer is fine.

You can see

moving time (the gps believes you are moving)

stopped (the gps believes you are NOT moving)

 

The best value is the "saved track" value.

I think I know what stopped means, but thanks anyway. So you stopped for 3 minutes? Is it "fine" to add to the GPS odometer when stopped? The track adds points and makes a big cloud.

[freeday]

...

Total time 26+ minutes.

HCX stopped 13min moving 13min

CSX stopped 3min moving 23min

 

Are they both wrong? Did you stop at all? My guess has always been that all GPS odometers are bad.

The gpsmap60csx-odometer is fine.

You can see

moving time (the gps believes you are moving)

stopped (the gps believes you are NOT moving)

 

The best value is the "saved track" value.

I think I know what stopped means, but thanks anyway. So you stopped for 3 minutes? Is it "fine" to add to the GPS odometer when stopped? The track adds points and makes a big cloud.

i did not measure the time i stopped. It is only a tool for me to find the bug. (i do not need the stopping time really)

normally the gpsmap60csx shows to less stopping time and the Vista HCX to much stopping time

it is only a posibility for users to help finding the bug...

[dstedman]

My Vista HCX shows the same behavior when hiking through the woods. Lot's of zero's for speed while walking, and the stopped time is always equal to or more than the moving time, even though I never stop moving. Grrr....

 

Seems to me that my older Legend continues to show/record your last speed instead of dropping it to zero when it loses the satellites for a second. This is perhaps where the bug is?

 

While on in the car the moving/stopped times seem to be accurate.

 

This is all with the latest firmware...

 

dan