Accuracy plots of garmin gpsmap 62 st?
Vincent van der Laan
After using my trusted Meridian platinum for about 6 or 7 years it is time
to update. I might consider the garmin gpsmap 62 st, but only if it is more
accurate. Using official Dutch benchmarks my Meridian never was off by more
than 3 meters using EGNOS. (I can repeat my tests again and again and they
are consistant) The garmin gpsmap 62 st has to equal that or do better if I
want to buy it.
I'm looking for measured (not claimed by garmin) accuracy data of the garmin
gpsmap 62 st. SA Watch or Visual GPS plots would be fine.
I have googled for hours but have found nothing... at... all.
Even gpsinformation.net (which has a nice article about this gpsr) does not
mention anything about accuracy. Nice story about the menu's etc. but no
measurements.
Hmm, am I missing something here? The whole point of a gpsr is to pinpoint
position as accurately as possible? Or am I being naive?
Anyway: does anybody have accuracy measurements/tests of the garmin gpsmap
62 st? Help would be greatly appreciated!
TIA, Vincent
Alan Browne
> Long time no see....
>
> After using my trusted Meridian platinum for about 6 or 7 years it is time
> to update. I might consider the garmin gpsmap 62 st, but only if it is more
> accurate. Using official Dutch benchmarks my Meridian never was off by more
> than 3 meters using EGNOS. (I can repeat my tests again and again and they
> are consistant) The garmin gpsmap 62 st has to equal that or do better if I
> want to buy it.
I can assure that your GPS is only as accurate as local conditions. I
too can get 2 - 3 meter SBAS (WAAS) benchmarks if the sky is clear of
trees and other obstructions....
But leave my GPS in a forested area and let it record for 10 minutes and
the walk can cover 50 meters radius.
> I'm looking for measured (not claimed by garmin) accuracy data of the garmin
> gpsmap 62 st. SA Watch or Visual GPS plots would be fine.
>
> I have googled for hours but have found nothing... at... all.
>
> Even gpsinformation.net (which has a nice article about this gpsr) does not
> mention anything about accuracy. Nice story about the menu's etc. but no
> measurements.
>
> Hmm, am I missing something here? The whole point of a gpsr is to pinpoint
> position as accurately as possible? Or am I being naive?
Reception conditions can have a great effect on accuracy. Don't assume
when walking in the woods, or on a trail on the side of the mountain, or
in the urban canyons of the city that you are getting the same accuracy
as at a "clear sky view" benchmark.
--
gmail originated posts filtered due to spam.
Vincent van der Laan
> I can assure that your GPS is only as accurate as local conditions. I
> too can get 2 - 3 meter SBAS (WAAS) benchmarks if the sky is clear of
> trees and other obstructions....
> Reception conditions can have a great effect on accuracy. Don't assume
> when walking in the woods, or on a trail on the side of the mountain, or
> in the urban canyons of the city that you are getting the same accuracy
> as at a "clear sky view" benchmark.
>
Wormley about multipath, VDOP, HDOP, error sources etc.) so I totally agree!
I would like information on multipath handling as well.
And also: does the garmin do auto averaging when standing still?
I can't find any accuracy related technical specs.
Not even on Garmin's website.
Cheers, Vincent
BeartoothHOS
[....]
> I would like information on multipath handling as well. And also: does
> the garmin do auto averaging when standing still?
>
> I can't find any accuracy related technical specs. Not even on Garmin's
> website.
This may be urban legend, and if not probably requires
installations with a l-o-o-o-n-n-gg *fixed* baseline (originally between
MIT and CalTech iirc; and before geostationary satellites, I think, so
they may have had a third point on the Moon) -- but fwiw the technology
seems to've developed out of an experiment designed to allow measuring
continental drift. In inches per century. That's with the sky the limit
on cost, weight, everything else, of course; but afaik they did measure
it.
It's plausible insofar as NASA once boasted an ability to aim a
beam from Houston into a coffee cup on the Moon. And triangulation is an
exact science .... <grin>
--
Beartooth Implacable, PhD, Neo-Redneck Linux Convert
What do they know of country, who only country know?
mi...@sushi.com
On every Garmin I own, you have to select averaging. If you dig
through old posts on this group, averaging itself isn't as good as you
think. Now most of these GPSs will do some weighted average of the
satellites that they can see, based on SNRm but that is not like
averaging readings.
To measure accuracy, you really need to find a landmark that has been
measured accurately.
http://www.ngs.noaa.gov/cgi-bin/ds_mm.prl
It has been my experience that a great deal of these landmarks are not
exactly easy to access. Some are in the middle of the street! The
spots that can be seen from satellite are my choice. You can look at
them on google earth to determine access. You also want to make sure
you can linger on the spot if you want to do averaging. On my
gps60csx, using English units, I get readings good to 4ft with
averaging. Not spectacular, though it is sub-meter.
The satellite visible landmarks show up as a big X. Those google earth
bastards trespassed on some undeveloped land I own and set up a
landmark. [Yeah, I was surprised to see a big X show up on google
earth on my property.] The lines of the X appear to be north-south and
east-west. Anyway, if you see an X on google earth, it may not be a
permanent marking. The ones in the USGS database are painted, but the
survey points used by google earth are done with some sort of
biodegradable sheeting. Not as flimsy as paper, but it does decay.
Ed M.
solution from an iPhone 4, at this site:
http://www.geek.com/articles/gadgets/review-garmin-gpsmap-62-handheld-gps-device-20100810/
Apparently walking around a New York apartment complex with a lot of
foliage in some areas.
Worth reading the comments. One commenter links to his expanded
remarks here:
http://forums.groundspeak.com/GC/index.php?showtopic=253992&st=188
Note that all of this is nearly a year old, and there have undoubtedly
been software updates since then.
Sounds like the unit may have implemented a baro bias state in its
filter, which was common in the early days of GPS user equipment. A
lot of papers were written in the early 1980s, and maybe earlier, on
navigating with 3 satellites and a calibrated baro altimeter.
More comments on accuracy and the altimeter input here (again, almost
a year old):
http://gpstracklog.com/2010/06/garmin-gpsmap-62-62s-and-62st-announced.html
One web post asserts that the chipset is from ST Microelectronics, not
SiRF:
http://gpstracklog.com/2010/06/garmin-gpsmap-62-62s-and-62st-announced.html
STM is a bit stingy with details:
mi...@sushi.com
> A reviewer shows a track on a satellite photo, compared to the
> solution from an iPhone 4, at this site:
>
>
> Apparently walking around a New York apartment complex with a lot of
> foliage in some areas.
>
> Worth reading the comments. One commenter links to his expanded
> remarks here:
>
> http://forums.groundspeak.com/GC/index.php?showtopic=253992&st=188
>
> Note that all of this is nearly a year old, and there have undoubtedly
> been software updates since then.
>
> Sounds like the unit may have implemented a baro bias state in its
> filter, which was common in the early days of GPS user equipment. A
> lot of papers were written in the early 1980s, and maybe earlier, on
> navigating with 3 satellites and a calibrated baro altimeter.
>
> More comments on accuracy and the altimeter input here (again, almost
> a year old):
>
>
> One web post asserts that the chipset is from ST Microelectronics, not
> SiRF:
>
I don't expect any phone to be as good as a dedicated GPS. Smartphones
are Swiss Army knives. You cram a lot of electronics in them and put
them on a power budget too. I can tell you the GPS 60 compass sucks. I
set my up to use it rarely. You can set the break point between
between virtual compass (difference the GPS reading) and the flux gate
compass. Before I took it out in the back country, I did a few tests
and discovered there was really no way to make the compass be
accurate, certainly not when compared to a lensatic compass. I hope
the 3d compass is better, but still you don't get a "sight" with a
GPS, unlike the lensatic. If I need a vector, I use a real compass. I
have to laugh at those satellite pointing apps using the iphone. We
know the iphone GPS isn't great, and the compass is really really crap
You need at least two degree accuracy to set up a satellite dish
quickly. Those lensatic compasses are military quality at consumer
prices.
I see the 62 is more sensitive than the 60. Hey, time marches on. I'm
not exactly ready for an upgrade. I've run the 60 through some canopy
and it seems to do well. (Not so for my old emap). I like everything
about the 60 series except for the display. Black and white is far
better as a reflective display than color. I got a jacket for the
GPS60, but it is tough to read with plastic over the LCD. What worked
best for my emap was the yellow booty and a screen protector.
Supposedly there are iphone apps that contain map databases in memory.
I don't know anyone who has tried them. I can tell you as a GPS, the
iphone 3 is really crap. Maybe the iphone 4 sucks less, but as a
product, the iphone 4 is pretty crappy, well other than a gaming
platform. The iphone is way to flimsy for any serious backcounty
hiking. The stupid glass screen breaks all the time. I think all
phones should have screen protectors, but on a typical phone, you just
get a scratch on the screen. With the iphone, it shatters. The last I
looked, they want $200 for the Apple "genius" to replace the glass.
Alan Browne
> A reviewer shows a track on a satellite photo, compared to the
> solution from an iPhone 4, at this site:
>
> http://www.geek.com/articles/gadgets/review-garmin-gpsmap-62-handheld-gps-device-20100810/
>
> Apparently walking around a New York apartment complex with a lot of
> foliage in some areas.
I did a similar comparison some time ago between an AMOD 3080 (track
recorder) and my iPhone 4.
Some areas had good sky view and others a lot of foliage.
The iPhone track was 10 - 20 metres off (or more) for most of the track
(a 30 minute walk).
When I would go to an easily recognized point (Google Earth) and mark it
with the AMODS 3080, the error would be about 1 - 2 metres. (The AMOD
3080 is a WAAS receiver, so that performance is no surprise). The AMOD
could be off by 10 or more metres when I had heavy foliage to the south
of me.
That of the iPhone 4 could be over 20 meters.
From the recording I get the impression that the iPhone updates are 0.5
Hz or less. But that could have been the application I was using that
was under sampling. No way to tell.
All that said I think the iPhone 4 GPS is fine for what it is - it gets
the urban/sub-urban/extra-urban user to where he needs to go. It also
tracks quickly with a first est. position within 50 metres or so and
then that improves quickly to 10 - 20 metres.
For photography (recording position to tag photos), the AMOD 3080 is
great. (And I have a few available for purchase at a great price if you
need one. Bought some for a project and still have 3 new in their boxes).
mi...@sushi.com
wrote:
> On 2011-07-04 16:10 , Ed M. wrote:
>
> > A reviewer shows a track on a satellite photo, compared to the
> > solution from an iPhone 4, at this site:
>
Just a FYI, google earth is often off a bit. That is why I suggested
using the USGS reference points. I suppose if you aren't in the US,
they aren't too handy.
In the scheme of things, the average phone user rather than better
phone reception than better GPS reception. Especially true for any of
the iphones, which universally have poor reception. Hey, there is
always iphone 5. Apple is bound to get it right sometime. When antenna-
gate hit, they advertised for antenna/RF engineers. A bit late, but at
least they are attempting to fix the problem.
Alan Browne
I know. But when you test against a number of easy to identify points
at different locations you tend to get a feel for where there are
obvious errors and where there are not. I can also get Canadian ref
point data if needed - but then I have to translate them from older
spheroids to WGS-84. PITA. (There are online converters, of course).
> In the scheme of things, the average phone user rather than better
> phone reception than better GPS reception. Especially true for any of
> the iphones, which universally have poor reception. Hey, there is
> always iphone 5. Apple is bound to get it right sometime. When antenna-
> gate hit, they advertised for antenna/RF engineers. A bit late, but at
> least they are attempting to fix the problem.
The iPhone 4 GPS implementation is thin - even if "better" than in
earlier iPhones. In order to reduce battery consumption they use a
'weak' correlator and from what I observe in the data they don't sample
and process as often as a dedicated GPS. And of course it still uses
cell tower aiding (you can see this when you start a map program -
initial error circle is very wide (100 - 200m). Then once it latches on
to a few satellites the error circle shrinks quickly).
Given how well it performs for general navigation (where am I and where
is the restaurant) the compromise they've made for power seems
appropriate. In the next iPhone (which I won't buy) I hope they don't
compromise power to improve GPS - it's not worth it.
I do wish there was an App to allow me to drill down into the channel
data and log that, however.
Vincent van der Laan
b1453d03-c97c-4a33...@p30g2000prp.googlegroups.com,
"mi...@sushi.com" <mi...@sushi.com> wrote:
> It has been my experience that a great deal of these landmarks are not
> exactly easy to access. Some are in the middle of the street! The
> spots that can be seen from satellite are my choice.
I have been using Dutch benchmarks for years. Works very well.
The thing is: I would like to see some accuracy tests of the Gpsmap 62
BEFORE buying it. But apparently nobody on the whole wide www has done that
test yet.
I think it is strange that in all the reviews I have found the reviewer only
comments on features like ruggedness, menu's, geocaching options etc. and
nobody bothers to test accuracy.
Apparently nobody cares about accuracy any more these days...
Terje Mathisen
> comments on features like ruggedness, menu's, geocaching options etc. and
> nobody bothers to test accuracy.
>
> Apparently nobody cares about accuracy any more these days...
I think this is closer to the truth than you might like:
Pretty much all modern GPSs, with WAAS/EGNOS/cell tower assist, are both
sensitive enough and fast enough that most users are happy with them.
At this point absolute accuracy remains as a selling point only to real
geeks, like many of the regulars here. :-(
Terje
(Who is using GPS as an aid to draw and field check a new orienteering map.)
--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"
Vincent van der Laan
<"terje.mathisen at tmsw.no"> wrote:
> I think this is closer to the truth than you might like:
>
> Pretty much all modern GPSs, with WAAS/EGNOS/cell tower assist, are both
> sensitive enough and fast enough that most users are happy with them.
>
> At this point absolute accuracy remains as a selling point only to real
> geeks, like many of the regulars here. :-(
>
> Terje
> (Who is using GPS as an aid to draw and field check a new orienteering map.)
Exactly!
Anyway I have decided not to buy the gpsmap 62 due to serious elevation
recording problems.
Apparently the case of the 62 is so weak and the buttons displace so much
air that when you grip the unit tightly or push buttons, the altitude
readings go all over the place.
For a mountain climber/paraglider like me this is the ultimate dealbreker.
I am now looking for a secondhand 60csx, a much better engineered product.
Alas, garmin decided to end that line and follow it up with an inferior
product.
In the meanwhile I'm still using my old but very reliable and accurate
Magellan Meridian Platinum :)
Terje Mathisen
> <"terje.mathisen at tmsw.no"> wrote:
> Anyway I have decided not to buy the gpsmap 62 due to serious elevation
> recording problems.
>
> Apparently the case of the 62 is so weak and the buttons displace so much
> air that when you grip the unit tightly or push buttons, the altitude
> readings go all over the place.
I've read all the reports and seen the gpx file elevation excursions:
Pretty much a failed product. :-(
>
> For a mountain climber/paraglider like me this is the ultimate dealbreker.
Orienteering, skiing (xc/bc/alpine/snowboard), climbing, white water
kayak, single trail mt bike etc. The bike mount for the 76CSx actually
works very well. :-)
When on a semi-sinker windsurfer board the fact that the 76 series will
float is nice.
>
> I am now looking for a secondhand 60csx, a much better engineered product.
I personally like the 76 form factor better, I own both a monochrome 76S
and the color 76CSx. The internal hardware is of course exactly the same
as in the 60 series.
For orienteering races I use a 405 as a track logger:
http://tmsw.no/qr/index.php?user=terjem
Terje
mi...@sushi.com
> On 09-07-11 12:16, in article hdmle8-jd61....@ntp6.tmsw.no, "Terje Mathisen"
And I never used the barometer in my 60csx once. ;-) I just never
found a reason to know my altitude accurately, but I'm open to
suggestions.
If the compass is better on the 62, that might be a reason to buy it.
mi...@sushi.com
wrote:
What exactly are you looking for besides your location? Given the
hurdle to join the iphone app developers club (paying off Apple,
torturing oneself with objective C, getting approval), I can't see
anyone writing simple hacking software to read the gps in detail.
Android or Blackberry would be better for that purpose.
If you go to getjar.com, tell it you have an android device, then
search for gps, the exact program you want exists. It is called GPS
status:
http://www.getjar.com/mobile/32199/gps-status-for-google-nexus-one/?ref=0&lvt=1310273639&sid=i898o8fwhnkwk6y8&c=p6lunog4fzthmoc15&lang=en
There are a lot of java based GPS programs, but I don't see one as
detailed as GPS status.
There are free programs for Android and Blackberry that sniff the cell
tower information, but they also will dig into your phone innards.
http://www.cellumap.com/
http://f5bbutils.fairview5.com/signalloc5/
Cellumap is an interesting program and website. Really both in one.
The app records tower data from your phone and give you the option of
sending the data to their website. On the website, you can see signal
strength reports at the reporting locations. If it were used more, you
could compare phone and carriers. However, it gets no press.
Signalloc is just a cell tower sniffer program, but you can log the
tower info on your memory card, make a KML, etc.
Vincent van der Laan
> And I never used the barometer in my 60csx once. ;-) I just never
> found a reason to know my altitude accurately, but I'm open to
> suggestions.
Any sport that moves in 3 dimensions: mountain climbing, paragliding etc.
With mountain climbing I often follow route descriptions as:
"At 3506 m you will find the beginning of a ledge that you should follow
eastwards for 25 m before..."
Without an accurate altimeter I might miss the ledge altogether. In rocky
terrain it is very easy to miss such details visually.
(Mountains are challenging to GPS though: they often shield off several
satellites and there often are multipath problems.)
Alan Browne
> On Jul 8, 5:37 am, Alan Browne<alan.bro...@FreelunchVideotron.ca>
>> I do wish there was an App to allow me to drill down into the channel
>> data and log that, however.
>>
>
> What exactly are you looking for besides your location? Given the
> hurdle to join the iphone app developers club (paying off Apple,
> torturing oneself with objective C, getting approval), I can't see
> anyone writing simple hacking software to read the gps in detail.
My interest in GPS workings goes deeper than PVT to the SN, Doppler, PR,
SVN status and so on.
I suspect that Apple obfuscate the GPS workings in their API (if that's
the right term) and that it is inaccessible, generally.
Given the number of iPhone geeks out there who are iPhone developers,
there is bound to be one somewhere, someday who will do it - if the
information is accessible. As to hacking it, if the high priests of
acceptable iPhone practice detect a hack, they won't allow the App into
the App Store.
I have no intention of getting an Android or BB phone. I have an iPhone
and that will suffice for quite a while.
Alan Browne
How often do you recalibrate the altimeter? Is it automatic? How is it
filtered in the automatic solution? How do wind currents in the
mountains affect the altimeter (venturi effects, etc.)
Wolfgang S. Rupprecht
Vincent van der Laan <vin...@allalin.nl> writes:
> Apparently the case of the 62 is so weak and the buttons displace so much
> air that when you grip the unit tightly or push buttons, the altitude
> readings go all over the place.
The obvious fix is only one drill-bit away.
-wolfgang
--
Wolfgang S. Rupprecht Test your IPv6 compliance: http://test-ipv6.com/
mi...@sushi.com
wrote:
The iphone is to market apps. Mass market, mostly games. It is not a
hacker's machine. Android is the most likely place to find what you
want, though you never know about blackberry. I got a free app that
takes my GPS location and converts it to a HAM grid.
To really program an iphone, you need a mac, and no decent hacker
would on a mac.
mi...@sushi.com
wrote:
> On 2011-07-10 05:36 , Vincent van der Laan wrote:
>
>
>
>
>
>
>
>
>
You need to calibrate the barometer from either the airport ATIS or be
at a well defined altitude.
I prepare my hikes from the garmin topo and sometimes google earth, so
being where I should be is all I need.
Some people like to track elevation change as a measure of exercise.
As you know, only elevation change takes "work" in the strict physics
sense. All that lateral travel is free. ;-)
mi...@sushi.com
<wolfgang.ruppre...@gmail.com> wrote:
The vents on these GPS have some sort of membrane valve to keep out
moisture. Just drilling a hole won't cut it.
Terje Mathisen
> Some people like to track elevation change as a measure of exercise.
> As you know, only elevation change takes "work" in the strict physics
> sense. All that lateral travel is free. ;-)
This has been studied extensively in the context of orienteering route
choice, and the consensus is that every meter of ascent corresponds to
7-10 meter of horizontal travel.
Where you are in the 7 to 10 range depends on terrain, ground cover and
personal fitness. In my own testing I have found that average pace
(min/km) tend to be fairly constant when I use the 7 factor.
BTW, this is when I measure ascent by taking the number of contour lines
crossed going uphill and multiplying by the equidistance (normally 5 m),
it means that small ups and downs in relatively flat terrain can be
skipped completely, but when going up a hillside it is fairly accurate.
Terje
Wolfgang S. Rupprecht
"mi...@sushi.com" <mi...@sushi.com> writes:
> The vents on these GPS have some sort of membrane valve to keep out
> moisture. Just drilling a hole won't cut it.
Sure it will. That membrane is what is causing all the problems. When
it rains, just put the GPS in a ziploc bag.
Only half in jest...
Vincent van der Laan
"Alan Browne" <alan....@FreelunchVideotron.ca> wrote:
> How often do you recalibrate the altimeter? Is it automatic? How is it
> filtered in the automatic solution? How do wind currents in the
> mountains affect the altimeter (venturi effects, etc.)
I only have experience with my Meridian Platinum. It uses GPS altitude only.
The barometer is only used to track weather changes and is not coupled with
the GPS altitude. Therefore no wind effects. On the south slopes I usually
have EGNOS assistance.
In the Swiss Alps where I usually climb most paths are designated by
signposts that show you the direction, minutes to walk and very important:
the altitude of the signpost. Swiss altitudes are very precise always within
a metre (what else would you expect of the Swiss).
Above the cabin on my way to a mountain peak there usually are no signposts
and you have to know the altitude of certain terrain features.
So hiking up to a mountain cabin I will have maybe 5-10 chances to check my
altitude. If it is correct to within 3 meters + or - I won't bother. If it
deviates by more I will set it to the altitude displayed on the signpost.
Sometimes when I'm lazy I don't bother at all.
Because: the nice thing about the MP is that as soon as I stand still it
will start averaging the GPS measurements. That includes the altitude. The
longer I stay in one place the more accurate GPS altitude will be displayed.
Taking a 15 minute break usually got me within 3 meters accuracy (tried this
often at known altitudes).
I did however encounter multipath problems on numerous occasions.
Once a smooth vertical mountain wall acted like a mirror: the GPSr decided I
was 20 meters from the wall (which was correct) but on the other side, IN
the mountain :)
Alan Browne
I would think that when there is a good quality averaged position that
it would automatically update the altimeter if the GPS is using the
correct map datum for the are (not WGS-84).
> I did however encounter multipath problems on numerous occasions.
> Once a smooth vertical mountain wall acted like a mirror: the GPSr decided I
> was 20 meters from the wall (which was correct) but on the other side, IN
> the mountain :)
Could be - I've had odd GPS results with flat surfaces.
Interesting post. Thanks.
Ed M.
>
> Anyway I have decided not to buy the gpsmap 62 due to serious elevation
> recording problems.
>
> Apparently the case of the 62 is so weak and the buttons displace so much
> air that when you grip the unit tightly or push buttons, the altitude
> readings go all over the place.
>
Apparently Garmin fixed the altitude problem almost a year ago via
software update. Didn't find any specifics.
Follow-up posts by "sammydee" (whole entries worth reading for anyone
interested in this unit):
Post #284:
http://forums.groundspeak.com/GC/index.php?showtopic=253992&st=250&p=4433492&#entry4433492
"Bottom line: there's reason to believe that 2.44 fixes the altimeter
issue. "
Post #297:
http://forums.groundspeak.com/GC/index.php?showtopic=253992&st=250&p=4436648&#entry4436648
" . . . The elevation problem seems FIXED. The total altitude that the
62st reported was very close to what at least one other GPS reported,
and matches my expectation. I don't see any hint of problems when I
was pressing buttons on the GPS. The new beta firmware seems to have
done it's job.
. . . As for 62s vs. 62st ... honestly I've cached two weekends now
with calibrated maps I made, and with the built-in topo disabled. So
for ME I think I should have bought a 62s and saved $100. Your
decision might be different."
https://forum.garmin.de/showthread.php?t=5368
"Changes made from version 2.40 to 2.44:
. . . Fixed issues with inconsistent altimeter readings."
Terje Mathisen
> On Jul 9, 4:15 am, Vincent van der Laan<vinc...@allalin.nl> wrote:
>>
>> Anyway I have decided not to buy the gpsmap 62 due to serious elevation
>> recording problems.
>>
>> Apparently the case of the 62 is so weak and the buttons displace so much
>> air that when you grip the unit tightly or push buttons, the altitude
>> readings go all over the place.
>>
>
> Apparently Garmin fixed the altitude problem almost a year ago via
> software update. Didn't find any specifics.
It seems very reasonable that they could indeed "fix" this in sw:
Implement a barometer filter that has a variable time constant:
When no keys have been pressed during the last 2N seconds, use N as the
averaging time.
With key presses going on, increase N by 10
Alternatively, simply disregard any readings N ms around any key press.
Terje
Vincent van der Laan
Thanks, interesting links!
Alan Browne
> Ed M. wrote:
>> On Jul 9, 4:15 am, Vincent van der Laan<vinc...@allalin.nl> wrote:
>>>
>>> Anyway I have decided not to buy the gpsmap 62 due to serious elevation
>>> recording problems.
>>>
>>> Apparently the case of the 62 is so weak and the buttons displace so
>>> much
>>> air that when you grip the unit tightly or push buttons, the altitude
>>> readings go all over the place.
>>>
>>
>> Apparently Garmin fixed the altitude problem almost a year ago via
>> software update. Didn't find any specifics.
>
> It seems very reasonable that they could indeed "fix" this in sw:
>
> Implement a barometer filter that has a variable time constant:
>
> When no keys have been pressed during the last 2N seconds, use N as the
> averaging time.
>
> With key presses going on, increase N by 10
>
> Alternatively, simply disregard any readings N ms around any key press.
The last would be adequate and most simple to implement.