Forums > Windsurfing   Gps and Speed talk

The GPS debate

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Created by ka43 > 9 months ago, 15 Aug 2016
ka43
NSW, 3062 posts
15 Aug 2016 6:01PM
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As someone who turns on his GT31, uses it then puts the SD card in the puter and uses KA72 what are the alternatives when it carks it?? I know about the GW52 but what about the Garmin 920??
I have seen a few in action and it seems to be a very user friendly and simple platform (that's a big word for me).
Have any of the GPS "gurus" done any testing with the thing??
Is Locosys the only "player" that is being considered??
No hidden agenda here, I just want to know what alternatives for a dummy there is when I need to replace my GT31.
Im sure others are in the same boat.
Cheers,
Larko.

BSN101
WA, 2244 posts
15 Aug 2016 4:31PM
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Is the Thingsy available yet?

I've not heard/read it mentioned for quite s while.

Canmore is ok if your not chasing records.

sailquik
VIC, 6068 posts
15 Aug 2016 6:43PM
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There really is no 'Debate'. There simply is not any 'GPS-TC' suitable alternative to the GW-52 available at the moment as no other GPS can produce the SDOP data.

I think it is pretty clear that no big GPS company is likely to make a GPS that suits our quite specific needs in the near future. In the short term, the best we can hope for is to use what we have or hope that someone makes a device specifically designed for us that can be viable in very low volume production that meets our needs, in the way Raymond is trying to do with his 'Gyro', a Ublox based GPS in the pipeline now that will hopefully be a viable alternative and a significant step up in accuracy.

Others are working on similar 'home made' Ublox devices which may to may not be viable for low volume production.

Whether they prove to be as user friendly and foolproof as many people seem to want, will remain to be seen.

Re the GT31: If very well cared for, (and kept perfectly dry) there is really no reason why a GT-31 can not last for many years to come. About the only part that degrades is the battery, and that can be replaced if needed.(if the screws are not rusted solid! )

The following comment is certainly not aimed at you Larko. Just a general observation that seems relevant.

I have been in the GPS speed scene from the very start with a Garmin Etrex, through Garmin Foretrex and various other Garmins, to the GT-11, then GT-31, Canmore and GW-52. Along the way, every singe GPS has had a number of people who have whinged about how difficult the GPS is to use. No exceptions!

OTOH, I have always found them very easy to use when you take the time to read the manuals and learn how to set them up and use them properly as intended. Every piece of technology has it's differences which means we must adjust our practices and expectations. And yes, we make make the effort to learn, or re-learn to get the benefits and utility we desire. How is anything else in life worth pursuing any different?

sailquik
VIC, 6068 posts
15 Aug 2016 6:51PM
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Select to expand quote
BSN101 said..
Is the Thingsy available yet?

I've not heard/read it mentioned for quite s while.

Canmore is ok if your not chasing records.


The Thingsee One was a great disappointment. It had the potential to be everything to everybody, but there were shortcomings in the hardware, implementation and software design that caused the GPS-Speedsurfing guys to give up on it. It also turned out to be much more expensive than was originally promised.
The GPS-Speedsurfing guys attempt to write specialist software to suit our needs but ran into a lot of problems doing so. The specialised software also meant the device could not be used for any of the other things developed by Thingsee.

With the Canmore, you get what you pay for.

Subsonic
WA, 2963 posts
15 Aug 2016 8:31PM
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Re the gt31 battery.

I managed to kill mine through lack of use. . Too many months sitting in the box because I was too slack to put it on, which resulted in the battery sitting uncharged for too long.

So if you've got one, don't be slack like me, use it regularly enough and keep charging it, I'm sure it'll last for years.

Roo
765 posts
16 Aug 2016 12:28AM
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Building a GPS to meet our needs is the easy bit, making it waterproof is difficult. We operate in a harsh environment, crashing at speeds up to 50 knots and being underwater for periods of time. No gps can withstand those conditions without a bag and even then they tend to let some water in. The cost to make one that will function whatever the conditions is astronomical and not a commercial reality. Best advice...don't crash and don't fall in.

Once all the GT11/GT31s have gone to the great satellite constellation in the sky an android phone with the GPSLogit app will be all that's left at an affordable price, you can put together a package for $80. The new generation of 18hz gps are great for the dedicated speedsailors willing to live with their limitations but few sailors chase speed records and it's all about PBs now. Larko get a phone and GPSLogit app.

powersloshin
NSW, 1653 posts
16 Aug 2016 7:12AM
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I agree, so better assume that the units are not waterproof, not even splash proof. Once i saw the screws were rusting I have started sealing my GT-31 inside a food bag before sailing and it's going strong. They are really tough bags a lot ticker than the sandwich ones, only issue it's harder to look at the display.




Cocky2
QLD, 190 posts
16 Aug 2016 8:34AM
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If the Garmin 920XT will not be approved then the Canmore should be removed from the list. The Garmin is the best device for GPS for windsurfing and is more accurate than the Canmore and slower than GW52 .

TheTank
124 posts
16 Aug 2016 6:58AM
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sailquik said..
There really is no 'Debate'. There simply is not any 'GPS-TC' suitable alternative to the GW-52 available at the moment as no other GPS can produce the SDOP data.

I think it is pretty clear that no big GPS company is likely to make a GPS that suits our quite specific needs in the near future. In the short term, the best we can hope for is to use what we have or hope that someone makes a device specifically designed for us that can be viable in very low volume production that meets our needs, in the way Raymond is trying to do with his 'Gyro', a Ublox based GPS in the pipeline now that will hopefully be a viable alternative and a significant step up in accuracy.



Give it a couple of months and I believe Raymond's Gyro is the answer to our needs. He's posted some promissing stuff at the Dutch forum. The unit has been tested by several riders at different locations with good results. At the moment he's finetuning some last results for the @500. I believe that the first couple of units have been handed to the GP3S tech group for evaluation with high hopes for approval. If that goes well, from what I understand, the unit will become available for purchase. Haven't heared price yet but think I seem to remember it would be sub € 150,- so below 220 AUD.

The website
gearloose.nl

Topic at the Dutch forum
forum.windsurfing.nl/viewtopic.php?f=62&t=13890429

fanatic02
NSW, 300 posts
16 Aug 2016 9:15AM
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Larko . I have a spare battery for your gt . I've been using a garmin fenix 3 along with my gt31 . easier to read on wrist . love it . I compare results every session and there is bugger all difference in all categories

mathew
QLD, 2019 posts
16 Aug 2016 9:47AM
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Cocky2 said..
If the Garmin 920XT will not be approved then the Canmore should be removed from the list. The Garmin is the best device for GPS for windsurfing and is more accurate than the Canmore and slower than GW52 .

How is the Garmin the best device for GPS for windsurfing ? .... simply stating it, doesn't make it so - please elaborate.
And yes the Canmore should be removed. It was only approved for GPS team-challenge only because and they were cheap and available - the limited data that we had, made them look ok. However, there was no rigorous testing prior to it entering the community [ which is partly why we are now seeing workarounds to its bugs ].

mathew
QLD, 2019 posts
16 Aug 2016 10:10AM
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fanatic02 said..
Larko . I have a spare battery for your gt . I've been using a garmin fenix 3 along with my gt31 . easier to read on wrist . love it . I compare results every session and there is bugger all difference in all categories


"bugger all" isn't a objective / scientific measure of the difference between the devices. You are suggesting that "a few people like how the screen is readable, then they are accurate".... one feature, does not imply the other.

The Canmore has been found to not be suitable due to missing data-quality values (aka SDOP, EHVE, or other similar quality metric) and now we are also finding buggy hardware. As has already been posted in previous discussions, the Fenex data appears to be less accurate than the Canmore.

Why would we recommend a device that is much more expensive (x3), and less accurate ?

fanatic02
NSW, 300 posts
16 Aug 2016 10:33AM
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I didnt recommend it did I ? I just stated I use it along with my gt !!!!! and it's easy to read !!!!! also offering a good mate a battery you guys need to relax . it's supposed to be fun . ,

sailquik
VIC, 6068 posts
16 Aug 2016 12:36PM
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fanatic02 said..
....... I compare results every session and there is bugger all difference in all categories


Statements like this are extremely misleading and unwelcome. They encourage people who do not understand the critical shortcomings of a device like the Fenix to think it may be a viable alternative to an approved GPS for GPSTC postings.

The Fenix and it's ilk can be a very useful tool for feedback whist sailing in the same manner as GPS-Logit is, which I also use every session (and provides far more useful feedback than any watch), but one always needs to also use an approved, 'SDOP' capable GPS for competition posting. Currently, the GW-52 is the only one you can purchase new. It is the only device currently on sale that can be relied upon to produce verifiable data, despite what other shortcomings it may have.

The only thing likely to change that in the foreseeable future is the arrival of Ublox based stand alone GPS devices, or Bluetooth GPS receivers to use with GPS-Logit. There is quite a lot of activity going on right now towards that arrival.

fanatic02
NSW, 300 posts
16 Aug 2016 12:46PM
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you take it way to serious Daffy . misleading and unwelcome ?
bit harsh champ

decrepit
WA, 11828 posts
16 Aug 2016 11:11AM
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fanatic02 said..
you take it way to serious Daffy . misleading and unwelcome ?
bit harsh champ



Yes, but you're not in the position of trying to defend the viability of the GTC. Which is supposed to be about fun, but there are several people who take accuracy seriously.

The problems we are going to face in the next few decades will be down to a dumbing down of science and the rise of pseudo science, where uninformed peoples opinions are valued more that scientific, experts because they are more convenient or trendy.
The same thing is happening here, a trendy expensive watch is being touted as more accurate without any true assessment. This has led to some bitter divisions within our community already, please refrain!!!!!!!!!!!!!!!!!!!!!!

fanatic02
NSW, 300 posts
16 Aug 2016 1:17PM
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I never said once it was more accurate . I said there was bugger all difference . I didn't tell anybody to go out and buy it .
All this crap is starting to turn me off gps sailing . should be encouraging people not discouraging .

AUS4
NSW, 1249 posts
16 Aug 2016 2:53PM
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Select to expand quote
mathew said..


fanatic02 said..
Larko . I have a spare battery for your gt . I've been using a garmin fenix 3 along with my gt31 . easier to read on wrist . love it . I compare results every session and there is bugger all difference in all categories




"bugger all" isn't a objective / scientific measure of the difference between the devices. You are suggesting that "a few people like how the screen is readable, then they are accurate".... one feature, does not imply the other.

The Canmore has been found to not be suitable due to missing data-quality values (aka SDOP, EHVE, or other similar quality metric) and now we are also finding buggy hardware. As has already been posted in previous discussions, the Fenex data appears to be less accurate than the Canmore.

Why would we recommend a device that is much more expensive (x3), and less accurate ?



RED THUMB

sick_em_rex
NSW, 1598 posts
16 Aug 2016 4:56PM
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ok kids, let's all settle down here. Daffy, chill pill mate, Greg, you too.
The issue here is that our techno gurus, TO THEIR CREDIT, have tested many devices and found them mostly to have shortcomings and inaccuracies compared to our beloved GT31's. This has created a dilemma within our community. On one hand we want to retain the accuracy and integrity of units but all this accounts for nought if we don't have a viable alternative. Daffy it's all well and good saying you can replace a battery in a GT31 but in time there is going to be failures and unless we come up with a viable alternative we either A; lose people to GPS sailing because no device is around to replace it with or B; we allow a unit or units whose measurements are at least tolerable compared to the GT31. Don't forget, GPSSS exists for record chasers, GPSTC is our fun comp meant to encourage participants.
After reading the pages of issues being had with Canmore's and the overall 'clunkiness' associated with having to use a phone and an app and several other new devices that have not lived up to expectations, I myself will go the Garmin watch when my GT31 carks it and just not post anymore. I compete against me anyway and will never challenge for any titles....Until such time as an approved device does come about then I may return.
So Daffy, Decrepit and Matt, maybe some food for thought for the future guys.
Cheers,
Andrew.

Cocky2
QLD, 190 posts
16 Aug 2016 6:55PM
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Attached are 15 sessions comparing Canmore GP102 - Garmin 920XT and GW52.
The red highlighted is the highest reading for each session using KA 72 to download.













Ezric
NSW, 183 posts
16 Aug 2016 7:06PM
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Excellent post Cocky!

Looks like I need to get a GW52 to try and keep up with everyone.

decrepit
WA, 11828 posts
16 Aug 2016 5:34PM
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Cocky great work, but it would be better if the comparisons were sorted by time and not speeds. In a lot of the stuff I did, the results just ordered by there speed, weren't the same run. To be precise we need to know that the same runs are being compared with each other. That the 920xt is mostly under the GW52 is encouraging.
I think there's a need to think if the SDoP data is really necessary, for non record breaking results.
And personally I still need evidence of what happens when the watch is facing the water instead of the sky. I know sik_em thinks it's not an issue but I need to test it for myself.

sick_em_rex
NSW, 1598 posts
16 Aug 2016 8:12PM
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gonna start a crowd fund page for ya then Decrep to buy you a 920
And btw, surely Cocky's tables above relate to all 3 devices being worn at the same time to get all those figures. Haven't we had this conversation before???

Cocky2
QLD, 190 posts
16 Aug 2016 8:38PM
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The watch works fine facing down.

decrepit
WA, 11828 posts
16 Aug 2016 6:40PM
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sick_em_rex said..
>>>
And btw, surely Cocky's tables above relate to all 3 devices being worn at the same time to get all those figures. Haven't we had this conversation before???


Yes, and I thought I'd explained it then.

Just because you have similar results from the same date, doesn't mean they're from the same run! You have to compare runs not just results if want the whole story.

Probably most of the time similar results from different devices are going to be the same run, but out of 10 results I'd typically find 2 or 3 of the results were from different runs. Making the errors larger than they first appeared to be.

sick_em_rex
NSW, 1598 posts
16 Aug 2016 8:53PM
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but all the parameters we measure are not just 1 run. You must just then want to look at the data for the specific 2 sec and NM runs then I gather.....???
Is that really an issue that the results are from the same run? Surely even a pack of GT31's would give differences over the same run? I would have thought the fields where we give an average would be better metrics. Otherwise why is it mandatory to wear 2 GPS's if you want to claim a record?

rrdsailor
QLD, 120 posts
16 Aug 2016 8:53PM
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Excellent post Ian. Looks like i got to get a GW52 for a 10% increase
on my alphas.

decrepit
WA, 11828 posts
16 Aug 2016 7:30PM
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I was looking at 10 or 20 examples of the 2s and 10s results, that is what daffy wanted. As just one result, doesn't give an overall idea of what's going on.
When the 20 results from each device were ordered according to run, the numbers no longer looked as good





So this is a pile of 2s results from the same session, (and looking at it I see I've made a mistake in re-sorting it, the 16:16:68 watch result should be at the bottom.)
But there are several of the watches results no longer in speed order, just have a glance down them and some are a long way out of speed order, at the end you'll see a couple that aren't in the GT31s data. When they are in speed order but not run order the results look a lot closer.
The problem with this comparison is the SDoP of the GT31, it wasn't worn in an ideal position and it's accuracy isn't really good enough.

The biggest difference is over 0.5kt but the GT31 is +/- 0.35 so the fenex could be 0.15 to 0.85 out here.
That's why we need the GT31 or GW52 worn on the head for these comparisons.

sailquik
VIC, 6068 posts
17 Aug 2016 12:39AM
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Testing and evaluating the precision, consistency and reliability of the results of GPS devices is not a simple thing. It can't be summed up in a few sentences in a forum. Nor is this the place for the ad.hoc. presenting of 'evidence'.

It is not an emotional exercise either, but must be conducted with detached objectivity.

It has all been explained before, over and over in these forums and others. Experience seems to have shown that all this achieves for a vocal minority, is more confusion, when people continue to make unfounded and scientifically unsupported or invalid arguments, ask questions that have been answered over and over, or simply refuse to accept.

It reminds me of the so called 'Debate' about climate change. No amount of cold hard scientific facts and evidence can be found to satisfy the hard nosed 'climate change deniers'. Likewise, it seems like we can repeat the same things here, over and over, and some people just don't or won't get it because they just don't 'want' to.

The aim of the GPS tech advisors to the GPS-TC is to maintain the integrity of the competition. If results cannot be validated then they can't be trusted and will have no integrity. It's not about some lofty concept of ratified Records. How do you know or trust you have done a PB or really been beaten by your mate if you can't validate or trust the result from your GPS or his. Close enough, is certainly not good enough in any kind of competition, whether it is just for, fun, bragging rights at your local spot with a few mates, or in a team based national GPS competition, or even a competition with yourself to get a PB you can realistically have confidence in.

In this respect there is only one GPS currently on sale that's been through the most rigorous, carefully designed and scientifically evaluated testing for our specific use, and which produces extemly reliable and trustworthy accuracy, that can, most importantly, be validated for each and every single run. The GW-52 may have many shortcomings to many people, but it has been unequivically proven to be an order of magnitude more accurate than the much loved GT-31.

To even start to approach the rigour required to properly access another GPS that does not have error value output, one would need to side by side test a large number of identical units over hundreds of KM of varied speed as was was done by Dr. Tom Chalko with both the GT-31 and the GW-52. It would also include side by side geostationary testing in a variety of environments and other tests, depending on the type of GPS and update rate. (For example, aliasing tests using a mechanical oscillator). And even after all that, one would still not be able to present quantifiable evidence for each and every run to conclusively validate that run without the SDOP type data from the GPS system.

To properly evaluate a modern Ublox based GPS that also records Doppler error data will, thankfully, be very much less time consuming and work on that has already started on three continents.

Roo
765 posts
17 Aug 2016 12:00AM
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sailquik said..

The aim of the GPS tech advisors to the GPS-TC is to maintain the integrity of the competition. If results cannot be validated then they can't be trusted and will have no integrity. It's not about some lofty concept of ratified Records. How do you know or trust you have done a PB or really been beaten by your mate if you can't validate or trust the result from your GPS or his. Close enough, is certainly not good enough in any kind of competition, whether it is just for, fun, bragging rights at your local spot with a few mates, or in a team based national GPS competition, or even a competition with yourself to get a PB you can realistically have confidence in.



I think we need to be very careful how technical we get in evaluating GPS devices for the team challenge. I think in some respects we have gone too far but emotion has confused the issue. If we are going to demand devices that save error calculations to validate the results then we have to use the errors to make the results fair. Two sailors can record the same times but the SDOP may be different, so the only way you can truly say you beat your mate is to use the corrections to validate the data. If we don't what's the point of having it.....use it or lose it. If we are going to demand only approved devices be used then you have to use the data to validate the runs. This also means uploading the tracks and having the website run the calculations using the SDOP to correct the tracks. Who are we going to get to do this and is it what GPSTC participants really want?

AUS4
NSW, 1249 posts
17 Aug 2016 6:31AM
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If your so obsessed with the GT 31 and the GW 52 is expensive rubbish why don't you put in an order to the manufactures and order their minimum quantity to make it. You can't tell me they can't make them anymore.
Then you can shut down all this boring crap.



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Forums > Windsurfing   Gps and Speed talk


"The GPS debate" started by ka43