GPS units acceptable for Team Challenge

Well this will put the cat amongst the pigeons, but what gps units are acceptable for the Team Challenge. If the unit is allowed on GPS3S then by default it is allowed on the GPSTC? If you can post your speeds there and linked to here then that's OK?

As the GT31 is now at its end of life and no longer available what alternatives are available in each country. In the USA the only way to get into posting is to buy a phone and GPSLogit app, no GW52 are available.

Remember the GPSTC is all about participation and getting people involved, no sheep-stations at stake! Do we want more people involved, I reckon yes. If that is the case do we accept the new tech like phone apps but just put in brackets afterwards (GPSLogit) like we do for (Doppler) or (Trackpoint).

you could also get a canmore gp102 from the internet, they ship all around the globe !

That's the idea behind this thread Barton, to sort out what is acceptable for the GPSTC.

There's some complaint that the GPSLogit/Phone combo isn't that accurate in certain categories yet the GW52 has unusual reading for alphas at 5hz. Also different software gets different results with the GW52.

If the old Foretrex is still acceptable then the phone can't be that bad!

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bartontb said..

seanhogan said..
you could also get a canmore gp102 from the internet, they ship all around the globe !

Thanks for the pointer. I was unaware of the canmore product or that it was acceptable for GPSTC.

The price at www.canadagps.com/Canmore_GP-102.html is also very acceptable.

Thanks.

Edit update:
Just looked at the GPSTC rules and the Canmore is NOT listed, but neither is the GW-52. Maybe an update of the GPSTC rules and acceptable devices would also be helpful.

Yes I think the rules/devices section hasn't been updated for a while on GPSTC. I've been posting from my canmore for over a year.
You can find them on ebay and amazon quite easily and cheap.

I now use the canmore watch (fully waterproof,/doppler/1sec recording) works a treat !

side note, the canmore works just as well under a wetsuit as on the arm...awesome reception (much better than any locosys)
I tested two devices at the same itme at those two locations : exact same results.

Sorry to be negative, but I think Logit and associated hassles will put off more people than it converts. For introducing people to the GPSTC (which is the best thing which ever happened to windsurfing) a canmore or GW 52 is a much better option. So much less hassle, unless you are just using the logit to record your session without trying to hear what it is saying.

Background to this statement: I am captain of the Pinnaroos GPS team and have used a GT 31 for years but after reading Roo's experiences with the GPSlogit, I thought it had great potential to improve my speeds and I would try it.
I have found the apparatus the most frustrating equipment I have ever used - the phone keeps switching itself off or changing to other functions, I have tried Decrepit's Ferrero box cover but then you have no access to change/see anything once it is in the bag., and getting the phone in the waterproof bag without accidentally turning it off or changing functions is a challenge. Getting the volume loud enough so you can actually hear the speedchat is something I have rarely achieved even after fiddling with phone settings. Mostly I just hear a croak in the background. Salt water corrodes the earphone jack. The ear pieces get pulled out during sailing and the wind noise when the earpieces are in is unpleasant.
If I was introduced to GPS by a logit setup I would give it away as all being too hard. I am close to giving logit the flick anyway, but being the persistent individual that I am I will keep trying. Potentially it is a great tool to help the dedicated speedsurfer but I haven't been able to get it to work for me yet.

My POV is that consistency in how you post is more relevant.

99.999?% of us are not going to be contending for a world record.
The GPSTC does not offer any financial or other benefits to competitor or teams that win or place.

So what the problem with GPSLOGIT then? remember accuracy is ± (Plus/Minus) and not always in the positive, it's swings and roundabouts.

I still use a GT11 as my primary GPS and analyze data with Realspeed I only use GPSAR to check an irregularity with a file but still post with Realspeed data wherever possible for consistency.

I don't see what the issue is with posting on GPSTC with a phone and GPSLOGIT as long as that is what you do consistently not picking and choosing between devices and software to get the best result.

It's not cattle stations we're playing for

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Windxtasy said..
Sorry to be negative, but I think Logit and associated hassles will put off more people than it converts. For introducing people to the GPSTC (which is the best thing which ever happened to windsurfing) a canmore or GW 52 is a much better option. So much less hassle, unless you are just using the logit to record your session without trying to hear what it is saying.

Background to this statement: I am captain of the Pinnaroos GPS team and have used a GT 31 for years but after reading Roo's experiences with the GPSlogit, I thought it had great potential to improve my speeds and I would try it.
I have found the apparatus the most frustrating equipment I have ever used - the phone keeps switching itself off or changing to other functions, I have tried Decrepit's Ferrero box cover but then you have no access to change/see anything once it is in the bag., and getting the phone in the waterproof bag without accidentally turning it off or changing functions is a challenge. Getting the volume loud enough so you can actually hear the speedchat is something I have rarely achieved even after fiddling with phone settings. Mostly I just hear a croak in the background. Salt water corrodes the earphone jack. The ear pieces get pulled out during sailing and the wind noise when the earpieces are in is unpleasant.
If I was introduced to GPS by a logit setup I would give it away as all being too hard. I am close to giving logit the flick anyway, but being the persistent individual that I am I will keep trying. Potentially it is a great tool to help the dedicated speedsurfer but I haven't been able to get it to work for me yet.

Anita, I want to respond to your comments/frustrations but this is not the thread to do it in, so if you don't mind, I'll transfer my response to this thread: www.seabreeze.com.au/forums/Windsurfing/Gps/logit-musings/

- Barton

Personally my biggest concern is what happens when the display goes off on some phones, this is where the really big errors occur, and yes they're easy to spot if you know what you're looking for.
But I'd be happier if we could recommend a list of phones that don't have the "display off" problem and have good satellite reception, the half knot resolution isn't such a big issue, it's only going to lead to quarter knot errors, the other two can cause one knot and higher errors.

My Samsung Ace 3 is one such phone, but there's probably cheaper ones out there.

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Roo said..

There's some complaint that the GPSLogit/Phone combo isn't that accurate in certain categories yet the GW52 has unusual reading for alphas at 5hz. Also different software gets different results with the GW52.

Just to clarify this. It was found that RealSpeed has some problems finding Alphas with the 5hz GW-52 data.

But the other software analysis programs work as they should. Using GPS-Results to analyse Alpha 500's, the GW-52 data shows a much smother and more accurate map and speed curve in every case I have tested than a GT-31 used next to it. In short, the 5hz GW-52 is much better for Alphas!

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decrepit said..

Unfortunately it's all too easy for the display to turn off, this particular instance was caused by a 3 contact music player earphone in the H20 pouch, instead of a 4 contact smart phone plug. But any button accidentally activated or even water pressure on the display during a crash can do it.

So a list of phones that continue to work as normal with the display off would be a great help.

I'll provide this anecdotal evidence for the Alcatel OneTouch Evolve2:

I have 19 sailing sessions recorded. Looking at each one with GPSResults shows that in ALL the sessions the number of satellites stayed in the 9,10,11 category throughout the entire session (except of course on the 'rare' occasion when I put a divot in the water and submerged the phone, in which case the phone quickly recovered to the 9, 10, 11 satellite category once it surfaced ). This includes the early sessions before I started using the dowels to protect the phone screen and later sessions where the 3 contact music player earphone was causing random switching of music etc during the sailing session. In all sessions, the 'screen ON' selection was ticked.

This doesn't directly address the 'display off' performance question but does represent my preferred (typical) configuration of sailing with the display ON and demonstrates no adverse performance (during this small sample size of sessions).

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Trousers said..

seanhogan said..
I now use the canmore watch (fully waterproof,/doppler/1sec recording) works a treat !

Very interested in that watch - what model do you use?

It's called the Trainer
they just released a new version.

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Roo said..
Here's some comparison measurements from today.

Just got back from a mission to the coast. Ran with GPSLogit on Alcatel One Touch Model 4037T Android 4.4.2 phone on left upper arm and 2 GT31 on right upper arm. I have included both doppler and trackpoint measurements as it gives you a good idea how clean the data stream is.

Max and 2 sec were all at the same time stamp of 8:43:50

Max: Phone 42.590 GT31-1 42.181 +/-0.272 GT31-2 42.259 +/-0.253 Trackpoint: Phone: 42.951 GT31-1 42.533 GT31-2 42.566
2 sec: Phone 42.492 GT31-1 42.143 +/-0.272 GT31-2 42.172 +/-0.253 Trackpoint: Phone: 42.685 GT31-1 42.400 GT31-2 42.358
5 x 10 sec: Phone 38.781 GT31-1 38.558 GT31-2 38.563 Trackpoint: Phone: 38.834 GT31-1 38.830 GT31-2 38.875

10 sec run Phone GT31-1 GT31-2
1 9:16:18 203.4m 39.540 202.5m 39.357 +/- 0.255 202.5m 39.356 +/- 0.253
2 9:43:54 201.7m 39.206 199.4m 38.765 +/- 0.289 199.4m 38.757 +/- 0.258
3 9:56:03 200.9m 39.054 199.5m 38.773 +/- 0.286 199.5m 38.782 +/- 0.284
4 9:21.07 196.8m 38.259 195.7m 38.035 +/- 0.291 195.7m 38.004 +/- 0.277
5 9:32:56 194.7m 37.849 194.8m 37.859 +/- 0.265 194.9m 37.877 +/- 0.254

All in all the phone acquits itself pretty well.

'Pretty well'???

Well, I guess so if you are measuring with a stretchy string!

I have to say that an objective view of this 10 sec. run data is that the phone is over reading constantly by up to half a knot. Especially since the data from the two GT-31's is consistently extremely close and within 0.01 and 0.03 Kts of each other on all the 10 second runs. (this is why they are so good!)

It can be observed that the Maximin 99% error range of the GT-31's is between 0.253 and 0.291 Kts. This says that we can be 99% sure that the speed is at least what the reading says. To put it another way, if we had 100 GPS recording that run, at least 99 of them should read within the error range stated. But of course, with a Standard Deviation distribution, the vast majority of them would be with a small fraction of this, more like that range we see between the two you have listed, and almost certainly less than 0.1 knots.

For any sort of competition or ranking in our sport, 0.5Knots is a quite significant margin, even for a fun ranking without talking sheep stations!

I think your data just reinforces the case against allowing the Android Phone with GPS-Logit for posting where it counts for the team rankings and probably the top individual rankings.

Of course, this makes our current dilemma even deeper as, apart from the Thingsee One, which is quite expensive, and the Locosys GW-52, which is inexpensive but not as user friendly as the GT-31 to operate, other options for newcomers to the GPS-TC are seriously flawed.

Bottom line. Get a GW-52 for posting and use the GPS-Logit app for fun and useful feedback on the water.

With the current exchange rate it will probably cost you less than US$200 shipped from Australia!

Wow pretty sad day when a gps is rejected because it's within 0.5% of the GT31 when mounted on the other arm! Considering the canmore and foretrex don't have that level of consistancy it doesn't leave people much in the way of alternatives if they want to participate in the GPSTC.

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sailquik said..


'Pretty well'???

Well, I guess so if you are measuring with a stretchy string!

I have to say that an objective view of this 10 sec. run data is that the phone is over reading constantly by up to half a knot. Especially since the data from the two GT-31's is consistently extremely close and within 0.01 and 0.03 Kts of each other on all the 10 second runs. (this is why they are so good!)

It can be observed that the Maximin 99% error range of the GT-31's is between 0.253 and 0.291 Kts. This says that we can be 99% sure that the speed is at least what the reading says. To put it another way, if we had 100 GPS recording that run, at least 99 of them should read within the error range stated. But of course, with a Standard Deviation distribution, the vast majority of them would be with a small fraction of this, more like that range we see between the two you have listed, and almost certainly less than 0.1 knots.

Pardon me for asking the following questions, I'm not trying to be a 'buttinskie', just trying to understand the past and future approach used by the GPSTC for qualifying GPS devices.

How was the GT-11, GT-31, and GW-52, Canmore, Foretex, etc. qualified? What was the testing approach used and what was the 'gold standard' used to determine GPS accuracy (multiple devices tested on the same run?, anecdotal? , etc?)? How many units were tested to establish the deviation for qualified units?

Thank you,
Barton

Just to clarify, my post wasn't about what devices were/should be gpstc allowed, I did hijack the thread.... sorry

I run a freerace comp locally and as long as the gps records at one sec interval all devices are accepted.

I don't think gw52 is the holy grail either, to me it seems to have poor reception (as opposed to the canmore for example) and from what I read on other threads seems to be a bit complicated to run on a computer and not user friendly...

As for Gpstc :

I sort of see the view of those asking for the best device (error/doppler) but being a team challenge, maybe doppler and 1 sec recording should be enough for most every day sailors like me.

After all when it comes to individual speed records, the top guns do post on gps-speedsurfing.com/ don't they ?

My statement is more about logit not being that user friendly and reliable. I'd hate to loose a session just because the screen switched off or phone had no battery left due to screen on.

I've done some testing with two canmore gporter 102+, one on the arm and the other under an impact vest : perfect reception for both and identical results.
But the screen is tiny so forget trying to see your results on the move (or even in daylight at the beach..) best suited for those who can wait to be home and check their speed on ka72

sean

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Roo said..
Wow pretty sad day when a gps is rejected because it's within 0.5% of the GT31 when mounted on the other arm! Considering the canmore and foretrex don't have that level of consistancy it doesn't leave people much in the way of alternatives if they want to participate in the GPSTC.

Nobody's talking about rejecting, we're just trying to come up with a way to cope with our reservations.
And light can be seen at the end of the tunnel.
As Andrew says, patience please.