Forums > Windsurfing   Gps and Speed talk

The GPS debate

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Created by ka43 > 9 months ago, 15 Aug 2016
boardsurfr
WA, 2321 posts
2 Oct 2016 7:05AM
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sailquik said..
I wonder why they have not actually consulted with those who have worked with them and bought from them in the past about this development?


It's been a while so I may be wrong - but did the GW-52 not start out in wrist watch format, and then was changed based on feedback from "those who worked with them"? Which ended up a bit as a compromise that nobody really loves.

The watch format is attractive to many, and offers a much larger market that speedsurfing. Seems Locosys did listen - they implemented both 5 Hz doppler speed and accuracy values. That might just be the first wrist watch with this combination.

boardsurfr
WA, 2321 posts
2 Oct 2016 7:51AM
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sailquik said..

The rules are very clear: GT-31, GW-52 are the gold standard and must be used for posting scores that count for the team or for PB's and the top rankings.

The Canmore was allowed as a gap filler when nothing else was available and has since proven to be highly problematic. Although it was done in good faith, for what we thought at the time were good reasons, in hindsight was a mistake. No one who is serious about their PB's or rankings should be using them now.



That is a rather strong statement. Perhaps you could enlighten us why the Canmore is "highly problematic", and allowing it was a "mistake"?

I have indeed seen differences in the results from dual Canmore units when I analyzed the data with GPSResults:


But when analyzing the same data with GPS Action Replay, the results for the two units are very close:

The differences between the two programs are entirely due to how GPSResults chooses to handle missing data points - by invalidating the entire region. This is primarily an issue with the software (GPSResults), not with the data. I brought this up with Manfred Fuchs, but he insists the way GPSResults handles this is correct. Based on a few decades experience in analysis of scientific data and writing analysis software, I disagree.








Boombuster
QLD, 571 posts
2 Oct 2016 10:19AM
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Looks good I hope it can be approved




Simon100
QLD, 490 posts
2 Oct 2016 11:35AM
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I think the simplest way to look at this is that i recon 95% of people just want a reasonably accurate and reliable (waterproof) unit only a few people really care about the absolute accuracy which is questionable anyway. Just putting it out there but what are the odds that ka72 that holds all the relevant software and is set up to display all this data in quite detailed ways would better cater to the needs of the majorities that wanted a fun competition. I also would like to hear about the problems with canmores from what I have seen they are just a bit slower which doesn’t bother me.

decrepit
WA, 12135 posts
2 Oct 2016 11:06AM
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The main problem with Canmores is the random holes in the data.

Simon100
QLD, 490 posts
2 Oct 2016 1:09PM
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Has any one worked out if the missing data is from a malfunction in the system or simply when the device calulates a possible error it just discards that reading and doesnt log or display it.

decrepit
WA, 12135 posts
2 Oct 2016 11:11AM
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kato said..


decrepit said...
After what's been happening recently in global politics, I'm losing faith in democracy.



Don't lose faith Mike, in a world with lots of look at me and loud noises, it's in the spaces that the respect, understanding and hard work live and thrive.
I am constantly amazed by the technical knowledge and work that the gps3 and GPSTC tech groups put in just for the betterment of our sport.
Remember folks without verified data and an agreed tech system it's just "I 'm faster than you cos I am" and that is just white noise!

Keep up the great work




Kato, I haven't lost faith in the tech experts and the people who do great stuff.
It's just the way the noisy minority can adversely affect democratic outcomes.
I was of the opinion that the GTC should be a bit more democratic, but I've now changed my mind.
This was in response to Bugs74 call for more input from GTC users.

boardsurfr
WA, 2321 posts
2 Oct 2016 11:29AM
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decrepit said..
The main problem with Canmores is the random holes in the data.


Yes, the Canmore will occasionally have missing data points. But the same is true even for GW-52 data - here is an example from my last session:


The "time" should always show 0.2 seconds. The long breaks are from crashes and swims; the short breaks are from crashes. Canmore units seem to drop data a bit more often, and sometimes in a middle of a run, without a crash (which I have not yet noticed in GW-52 data, but I do not usually check for it, either). In the middle of the run, it's usually just a single data point that missing.

If a data point is missing, GPS Action Replay seems to just take the speed shown two seconds instead of one (for 1 Hz data). That is probably not as accurate as having both data points, but whenever the speed changes slowly, it will be close. In contrast, GPSResults seems to simply drop the 2 second point from the calculation when filters are on; when filters are off, the results seem to be completely wrong. Either way, the result that GPSResults gives is (a) most likely less accurate than the one from GPS Action Replay, and (b) will be lower.

But note that the same discussion also applies to any points that are filtered out for whatever reason - because SDOP is too high, or acceleration, or HDOP (or, in the GPSAR filters, speed). When we actually need SDOP to identify "bad" data points, the effect is exactly the same as when the Canmore misses a point for whatever reason.

boardsurfr
WA, 2321 posts
2 Oct 2016 11:48AM
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Simon100 said..
I think the simplest way to look at this is that i recon 95% of people just want a reasonably accurate and reliable (waterproof) unit only a few people really care about the absolute accuracy which is questionable anyway.



I agree - although the accuracy should be good enough so that random errors do not mess up rankings. In my experience, that is the case for the Canmore, especially if you use GPS Action Replay to analyze the data. GT-31 accuracy levels have worked just fine for years, more accuracy is just gravy, but not necessary.

"Waterproof" is a different issue - the Canmore certainly is much easier to break by getting it wet than the GT-31 was. But the touch screen on the GW-52 seems a bit sensitive, too. At least the GW-52 is readable! It would be cool if the watch would turn out to be good enough.

As many shortcomings as the Canmore may have, it's still a great unit to get people into GPS speedsurfing. Maybe that's not a big issue in Australia, but it is in the US. Since the Canmore costs only 1/3rd of the GW-52, we were able to get 10 loaner units for an event we recently had, to get windsurfers exposed to GPS Freeracing (only 2 of the competitors had their own GT-31s). A lot of guys who participated really like it, and a couple already bought their own GPS. More about the racing at boardsurfr.blogspot.com/2016/09/who-is-faster.html

MartinF2
QLD, 484 posts
2 Oct 2016 2:02PM
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Boombuster said..
Looks good I hope it can be approved





I was not trying to reignite old wounds but show there is a new device potentially available which might stop all this bad vibe. Can the committee please contact Locosys for testing of this unit for our needs. Nothing more. Maybe I should have created a new topic instead. Sorry.
Cheers
Marty

sailquik
VIC, 6094 posts
2 Oct 2016 5:54PM
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MartinF2 said..
........ Can the committee please contact Locosys for testing of this unit for our needs............
Cheers
Marty


Already being attended to.

mr love
VIC, 2352 posts
2 Oct 2016 7:58PM
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I assume you wear it on your wrist...how will it perform facing down as most sailors I assume swap grip between up and down?

choco
SA, 4032 posts
2 Oct 2016 7:56PM
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Boombuster said..
Looks good I hope it can be approved






It looks like or is the GW 52 without the case

MartinF2
QLD, 484 posts
2 Oct 2016 7:42PM
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choco said..

It looks like or is the GW 52 without the case




Yes Choco. That's what makes it so tantalizing.





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sailquik said..

MartinF2 said..
........ Can the committee please contact Locosys for testing of this unit for our needs............
Cheers
Marty



Already being attended to.


Thank you Andrew.

decrepit
WA, 12135 posts
2 Oct 2016 5:55PM
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mr love said..
I assume you wear it on your wrist...how will it perform facing down as most sailors I assume swap grip between up and down?


That is my main concern as well, and what I have against any watch until somebody proves it otherwise.
I can just imagine how successful we'd be in convincing everybody a watch needs to be worn on the head!!!

Some of the data I looked at earlier seemed to show a discrepancy between tacks, but we haven't seen enough watch data, with details of how it was worn to tell.
The other possible problem, that will only add to the above, is perhaps a smaller antenna to fit in the watch. The Gw52's sensitivity isn't brilliant, (on my head yesterday, I only had 6 satellites during my best run), anything worse and upside down, is not going to give good results.

Cocky2
QLD, 190 posts
2 Oct 2016 8:24PM
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If you were interested in looking at data for a watch you would have already done so with the Garmin 920XT. I have emailed GPSTC On 3 occasions and you have never wanted files which are all stored in KA72. Sailquick comments are saying that by comparing devices worn in the same place in an aqua pack on upper arm at the same time is not a comparison. If this is the case then every post I have every done to quote Sailquick is "next to useless".
Also twice I have asked GPSTC about using multiply devices and picking figures from different files. You will not answer this question or put it in the GPSTC rules. This makes your statements about devices accuracy look hypocritical.
Why do you not put how you want testing done in GPSTC and then utilise the many people happy to help you test new devices?

Simon100
QLD, 490 posts
2 Oct 2016 8:35PM
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Cocky2 said..
If you were interested in looking at data for a watch you would have already done so with the Garmin 920XT. I have emailed GPSTC On 3 occasions and you have never wanted files which are all stored in KA72. Sailquick comments are saying that by comparing devices worn in the same place in an aqua pack on upper arm at the same time is not a comparison. If this is the case then every post I have every done to quote Sailquick is "next to useless".
Also twice I have asked GPSTC about using multiply devices and picking figures from different files. You will not answer this question or put it in the GPSTC rules. This makes your statements about devices accuracy look hypocritical.
Why do you not put how you want testing done in GPSTC and then utilise the many people happy to help you test new devices?


Do people actually post from multiple devices?

decrepit
WA, 12135 posts
2 Oct 2016 6:55PM
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Cocky a while ago I would have welcomed your files, but after getting red thumbs for my efforts, I'm no longer interested.

If people are posting from multiple devices, there bad sportsmanship should nag their conscience. I've seen no evidence of this happening. People I know who wear more than one device do so for back up purposes.

Cocky2
QLD, 190 posts
2 Oct 2016 9:08PM
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There are many of us who want to help however the committee does not seem to involve others.
Please put in the rules that you can not use multiply files then people should no longer do it.

vando
QLD, 3416 posts
2 Oct 2016 9:59PM
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choco said..

Boombuster said..
Looks good I hope it can be approved







It looks like or is the GW 52 without the case



Without the touch screen i think

Boombuster
QLD, 571 posts
3 Oct 2016 7:44AM
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We all would like a waterproof GPS, no more drowning no more having to wear a waterproof case or bag that slips down and is hard to see your results so where is the best spot to wear it some would say on your head but most don't want to or you could wear it strapped on your arm. The wrist is the perfect spot to wear a watch size device yes the device is going to be up or down so I would expect Locosys might have put the antenna in the wrist band so it might pickup the signal well. The picture is my GW-52 that drowned I spent days washing it out drying it only to get it to partially work. The circuit board and battery is under the screen but the antenna is the square thing hanging out its 6mm thick x 18mm square the whole case is mostly one third empty as you can see so most of it could fit in a watch case but not the antenna so I think Locosys will be looking at putting it in the band as are most smartwatches on the market. I have been doing GPS sailing for about 8yrs in this time I have drowned about 3 units which have cost me around $700 and then add the prices of waterproof bags which I change every year.



Simon100
QLD, 490 posts
3 Oct 2016 8:56AM
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Looking at what glynn just posted id be suprised if the gw52 isnt discontinued soon. Looks like they were just waiting on something for the watches.

Boombuster
QLD, 571 posts
3 Oct 2016 9:41AM
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Simon100 said...
Looking at what glynn just posted id be suprised if the gw52 isnt discontinued soon. Looks like they were just waiting on something for the watches.


It is discontinued out of production now.

Stretchy
WA, 943 posts
3 Oct 2016 7:54PM
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My comment is from the perspective of someone who is in it just for a bit of a lark. I dont have the skill, the time or the money to ever be really competitive, though it is still a bit addictive!! What I value above all else is the terrific GPSTC community that is out there, so I think it is really a bit of a shame the amount of negativity that occurs on here, in both directions, as soon as devices are discussed. if the GW52 is out of production , then this seems to be getting a bit terminal?
So the issue with some devices seems to be more about precision than accuracy; could we abandon stats that are more prone to error? What I mean is, if using a Canmore or a watch, is the error with 5x10 and NM less of a problem then it is for a 2S or Alpha? Maybe use 5x4S and 5xalpha Instead? Or leave 2S and alpha in just for bragging rights but don't have them count towards team scores?
Happy to be corrected, just wanted to ask the question - maybe it's time for a different approach?

Simon100
QLD, 490 posts
3 Oct 2016 11:15PM
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Thats a very sensilble solution and even forgetting the argument of acuracey /precision going with larger averages can only help with all devices and eliminate the lucky gust you know that other guy got id like to see 500m as a class instead of 2sec as the nm is to far for alot of people and the 2 and 10 really are temporary speed tricks the leave the newer sailors feeling alot slower than they are as they are often reasonably quick arcross wind. Especially for the team scores i recon using the averages would work great and make a fairer competition. But this is all been brought up before and some people love there 2 second.

Simon100
QLD, 490 posts
4 Oct 2016 10:02AM
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I think to sum up the intentions on the technical side i see things a bit different but more relevant i see it as more of a fun comp we only sail 7m and slalom gear in open water most of the time so i would in no way call myself a serious speed sailor however that is enough to get over 40 knots get jelly beans and sometimes our team even goes well in the comp. I do have an interest in seeing how fast i can go on the equipment i have in the conditions we get. On the home made gps I realise that you have an extremely limited understanding of anything even slightly complex but well actually i don’t even know what your upset about here. About all your penis references that’s just weird really are you on the sex offenders register? I like the nm it’s my favourite category you just can’t read very well nothing like doing over 30 knot nm in open water for fun. With the canmore being the only gps in production there would be a real need for more options also in my opinion the lack of waterproofing is an issue. I don’t look for any tech head way to sail faster I have the slowest gps available and i don’t care because its close enough I can always just sail a bit faster to make up for it.Hahaha always trying to get our team banned to make yourself seem slightly faster I don’t get that I enjoy the competition and if every one isnt there to race what is the point .

>>> this was posted in reply to that crazy guy from down south who always makes up accounts makes empty threats then gets deleted

66WSF
QLD, 408 posts
4 Oct 2016 10:10AM
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Does that mean I can use a 920XT ?

azymuth
WA, 2031 posts
4 Oct 2016 9:32AM
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Simon100 said..
nothing like doing over 30 knot nm in open water for fun.



Agreed - I'm surprised that more don't give it a go

Only need 20 knots of wind and we've all got access to "open water".

I reckon it's as much fun as an epic 2 sec on flat water

JJ

sailquik
VIC, 6094 posts
4 Oct 2016 2:07PM
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I was not going to comment on this thread again but I have been convinced to at least say this:

I think the forums are not the place to discuss technical stuff. There are too many people who just don’t understand the technical issues, valid scientific method, what is valid statistical evidence etc. And then there are those who think they do know, but their statements and questions say otherwise.

I could go on and on explaining things over and over but it gets really tiresome after a while. And there is always someone who does not understand the subtleties who wants to start an argument that muddys the water so much that no can can see anything.

It would actually be great if we could enlist all the willing people to help with some sort of testing, (I do appreciate your willingness Cocky2) but the type of testing that is required is not really able to be done in the ways they envisage. I am having trouble getting enough identical units together myself at the moment to do some Ublox testing.

If anyone wants to send me at least 5 of any type of GPS they would like tested, please do. We simply do not have those resources. And just doing the testing does not even remotely guarantee that anything tested might pass muster.

Please PM me with questions, suggestions or offers.

pierre
QLD, 166 posts
4 Oct 2016 11:45PM
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Hi Guys , long time no see After reading this thread i can feel a lot of guys are not happy with all kinds of gpss thats on the market today when it comes down to accuracy , we have to keep in mind that GPSSS and GPSTC is a very competitive site and u have to face it as soon as you have challenges and using numbers to define who will be the winner that is competitive and it is necessary to have good gpss to give much as possible the correct data and to be accurate ...

I have to say ive been in this GPSTC right from the start and hats of to the admins for putting in the hard work but the site has become an individual sport , team challenging is just about long gone and it doesnt make sense anymore to challenge other teams in other states or internationally when your not on the same water at the same time for me its a lose lose situation and its been going on for a long time like that , even its hard when 2 teams are on the same water and there is not much interest of challenging each other because certain divisions are taking over the gps sailor so the team spirit does lose out and man how many guys are interested in all divisions , very little .I can even remember back in QLD when we went out it was all about the 2sec and the 5x10sec , hardly ever we thought about alphas and NM or let alone kms so the spirit of the team was already lost there and this is still today this sort of behavior which a lot of sailors are loosing there ability to get better at sailing and tuning because of this gps mind set , man the new thing these days what is popping up is VMAX speed like WTF have we gone so far back !!!!ive been thinking about an idea for a while now and with the help of the admin from GPSTC and most of all you guys if u think this is a good idea , which is how about we transform the GPSTC to a different category and setup ..How about for example so please help me out or even better help each other out that we change the divisions into a category of 250m , 500m , NM , alpha and 1 hr is still debatable and like simon 100 said to get an average out if the results for example 2 fastest speeds average from 250m and the same from the other divisions that allow that .
But the point is to get back into real speedsailing , so the divisions that i have mentioned are not fixed and are all debatable so please share your thoughts...
But the point of this challenge would be no more teams but the individual himself and the main priority would be SPOT RECORDS and PB to the individual at a certain spot so not all the glory goes to the fastest guy so it would be good to read a certain sailor got a PB at that location and it will give other sailors a chance to beat it or challenge it or even better try to beat your own PB where you got it at the same spot..I would divide each sailor to a category of Gold , silver and bronze fleet so out of these 3 fleets each has a spot record to there category so this evens out the plaining field and makes it more fair for everyone and not only the fastest guy is acknowledged , so you put youself in a catergory which u think suits you best to challenge and in time if you think u have gotten better then why not jump up to the next category and bring on a new challenge for yourself..

Last of all as an add on we should also put onto the site an EVENT page and from there we can organize among ourselves at a certain location to do a event in between certain times to make it fair and get as much as possible of all category's to join in and have a crack at it , its competitive and fun and most of all fair for all ..

thats my 2 cents worth which i reckon can boost up the GPS sailing again and make it more interesting and challenging .

The GPSTC was good at the beginning but it has faded out and its causing a lot of arguments and other disputes and i say also that 2 sec is not the go and some other divisions in there also , for me its leading to no where .And the good thing about this new site we will have the first PROPER gps sailing website doing proper speedsailing ..I think that a donation will be needed to the GPSTC admims to start up this kind of site and i would be happy to donate first we needed if u guys think this is a good idea for a change and some good advice at the moment would be great so we can work together on this and try to achieve something ..



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Forums > Windsurfing   Gps and Speed talk


"The GPS debate" started by ka43