My GT-31 froze twice and has worked once since.... But this got me scared about a replacement.
Has anyone used it?
www.suunto.com/en-au/sports-watch-collections/Suunto-Ambit-Collection/
I don't know if the gps is of high enough accuracy for our needs. All I can find out is this vague reference to the Integrated GPS.
The integrated GPS used in wristop devices, such as Suunto Ambit, is based on the SiRFstarIV technology. The receiver has a very high sensitivity. This helps Suunto Ambit to find GPS satellites much quicker and get steadier readings.
The chip spec website isn't that helpful....
www.qualcomm.com/products/sirfstar-iv-4e
There are about 25 installable apps listed, some of which have a GT-31 logo...
www.movescount.com/apps
The Suunto Ambit2 is claimed waterproof to 100m costs about $500. Or $USD400 on eBay.
The 2s is only waterproof to 50m, and costs about $360.
www.fitshop.com.au/search.php?search_query=ambit&x=-1267&y=-93&gclid=CLuaw9S9jLsCFYFgpAodK3oAdQ
No , I tried one a year ago , only logged about every 5 seconds , it had a 1 sec setting but didnt work .
I was dissapointed as it cost alot of money .
There is a speed windsurf app for ambit watches.
www.movescount.com/apps/app10015234-5x10S_MAX_AVG
Quote from http://www.movescount.com/:
Calculates the 5x10sec MAX AVG like the GT-31 does. There is only one best 10sec average per run. A run is finished if either the speed drops below 8 knots or the GPS heading turns more than 70 degrees within 4 seconds. It also beeps whenever the 10s MAX improves. When the speed is over 8 knots, then it shows the current speed in knots, otherwise it alternates between 2s MAX, 10s MAX and 5x10s MAX AVG in a 3 second interval.
I will receive my own watch (ambit2) this month and I will report you guys how the logging works with these new models.
Select to expand quotefin224 said..
There is a speed windsurf app for ambit watches.
www.movescount.com/apps/app10015234-5x10S_MAX_AVG
That's a cool little app. Seems very easy to write your own, too.Select to expand quotefanatic02 said..
No, I tried one a year ago, only logged about every 5 seconds, it had a 1 sec setting but didnt work.
I was dissapointed as it cost alot of money .
Logging at 1 second intervals is definitely possible - check the shorter windsurfing runs at www.movescount.com/moves for examples. It seems that the data on the movescount are spaced depending on the length of the "move" - very short runs have 1 second resolution, longer ones 5 or 6 seconds between data points. It is possible that uploading data to the web site and then downloading again reduces resolution; converting data on your PC or Mac to GPX should fix that.
The Sirf IV GPS chip in the Ambit watch is 5 years newer than the Sirf III in the GT-31, and theoretically should be more accurate. But reception is probably the bigger issue. The antenna in the watch is probably smaller than the one in the GT-31; and using an under-grip (palm facing up) on the boom with a wrist-mount GPS will affect the reception negatively, too - human bodies are great GPS signal blockers.
The "FusedSpeed" feature sounds kind of interesting, since it uses both GPS and acceleration data. However, they say it's only for running and walking, not for other sports. I guess it's really useful for running, where the movement of your arm can distort the speed by 50% or more. Quite possible that the filter they are using makes assumptions about regular forward-backward motions.
A lot of speculation - I'd love to see some data files, but I don't think I'll spend $400 anytime soon.
Interesting. I have just read the user manual:
* Logs at 1 second in the windsurfing app mode.
* Logs GPX file.
* AFAIKT it uses location data, (trackpoints), to calculate speed which is proven far more inaccurate than speed data from 'speed over ground' (Doppler derived speed). It is no more accurate than the older Garmins that only gave us trackpoint calculated speed and could be up to 2 knots off.
* It also appears that to the data from the unit one must do it via an online app.
It does not (yet) meet the standards needed for reasonable GPS competition rankings.
In short, a pretty face with little substance behind it.
Select to expand quotesailquik said..
Interesting. I have just read the user manual:
* Logs at 1 second in the windsurfing app mode.
* Logs GPX file.
* AFAIKT it uses location data, (trackpoints), to calculate speed which is proven far more inaccurate than speed data from 'speed over ground' (Doppler derived speed). It is no more accurate than the older Garmins that only gave us trackpoint calculated speed and could be up to 2 knots off.
* It also appears that to the data from the unit one must do it via an online app.
It does not (yet) meet the standards needed for reasonable GPS competition rankings.
In short, a pretty face with little substance behind it.
I should add: If Suunto were able to activate writing and saving of the Sirf Binary files (SBN or SBP) in this device it should give us the same accuracy we get from the GT-31. In this case it would be quite attractive as an alternative to the GT-31 for GPS-SS and GPSTC.
How about it Suunto?
I had the suunto x10 , I set it for 1 sec but was only reading every 5 !
Was a great looking watch but wasn't doing the job
I have gotten a response from Suuonto:
"In regards to your concern, we would like to inform you that the GPS speed is based on position data. Doppler can be more accurate but fails in some situations, like running and walking. In these sports we have FusedSpeed to help the calculation and running pace in Ambit2."
Since there are probably more than 100 runners and triathletes for each windsurfer, providing FusedSpeed to compensate for arm movements certainly makes sense. But it does not explain why they don't provide access to doppler speed for other sports.
Kind of a bummer, since they also offer the "GPS Track Pod" for $130. It does not have a display, but can be either be used alone, or be linked to one for their watches for displaying speed. Total cost for both would be around $300, cheaper than the Ambit watch. I always log my speeds, but don't look at them on most days, so using only the Track Pod would be a viable option for me. It's "Water resistant to 30 m/100 ft (ISO 22810)", which sounds great.
I wrote that little app for the Suunto Ambit. For the Suunto Ambit 2 and 2S it is nicer to have the 2s, 10s and 5x10s MAX in separate apps, so that you can look at each individual graph on movescount.com. Those separate apps are not public yet.
sailquik: I met fin224 the first time this year at a windsurfing slalom contest. During summer we usually have a GPS speed challenge contest going on here in Finland, that's we we are interested GPS stuff :).
Here is a log*.xml that gets written to the harddisk right after Moveslink2 syncs the moves from the watch and before it sends them to movescount.com:
www.chumba.ch/windsurf/log-CD83095110001A00-2013-12-10T09_16_23-7.xml (you have to download it and open it in a text editor, because it is not a valid .xml file)
As you can see, there are different SampleType tags. Just the "periodic" one is taken every second. The ones from the GPS (gps-small and gps-tiny tags) are only every 3-4 seconds. That's a bummer because they would contain all the info from the GPS. The speed is not taken from the GPS, since it under the "periodic" sample. Same thing when exporting to .gpx. The trackpoints are only every 3-4 seconds.
Together with another friend we are in contact with Suunto. It would be great to get the watch to output optionally the SirfStar binary protocol (same data as in .SBN files). The GPS should basically be able to send every second.
It would be nice to be able to use just the watch for GPS speed surfing, but now I have to take the GT-31 as well to get reliable results.
It sounded like Suunto is willing to do some development for other sports. Let's hope we can get some 1s data with doppler speeds.
Select to expand quotefin151 said..
I wrote that little app for the Suunto Ambit. For the Suunto Ambit 2 and 2S it is nicer to have the 2s, 10s and 5x10s MAX in separate apps, so that you can look at each individual graph on movescount.com. Those separate apps are not public yet.
sailquik: I met fin224 the first time this year at a windsurfing slalom contest. During summer we usually have a GPS speed challenge contest going on here in Finland, that's we we are interested GPS stuff :).
Here is a log*.xml that gets written to the harddisk right after Moveslink2 syncs the moves from the watch and before it sends them to movescount.com:
www.chumba.ch/windsurf/log-CD83095110001A00-2013-12-10T09_16_23-7.xml (you have to download it and open it in a text editor, because it is not a valid .xml file)
As you can see, there are different SampleType tags. Just the "periodic" one is taken every second. The ones from the GPS (gps-small and gps-tiny tags) are only every 3-4 seconds. That's a bummer because they would contain all the info from the GPS. The speed is not taken from the GPS, since it under the "periodic" sample. Same thing when exporting to .gpx. The trackpoints are only every 3-4 seconds.
Together with another friend we are in contact with Suunto. It would be great to get the watch to output optionally the SirfStar binary protocol (same data as in .SBN files). The GPS should basically be able to send every second.
It would be nice to be able to use just the watch for GPS speed surfing, but now I have to take the GT-31 as well to get reliable results.
It sounded like Suunto is willing to do some development for other sports. Let's hope we can get some 1s data with doppler speeds.
Hi Fin151, Good to hear that there is strong interest in GPS speedsailing in Finland! 
It would be great if Suunto is willing to meet our needs.
If memory space or processing power is a limitation, the abbreviated Sirf binary format SBP would be a completely acceptable option.
Hello!
I exchanged few messages with SUNNTO in April last year (April 2013). Here is what I got from them: please be informed that at the moment the speed is based on gps distance, not doppler and in running sports the FusedSpeed adds the accelerometer measurement to speed calculations. Distance based speed calculations give better result in lower speeds than doppler speed. we will however add doppler speed as a wish on the feedback list and hopefully it will be available with the next ambit updates!
No news since April 
This is a pity because the Doppler Speed is actually available in the SIRFIV ship...
I had also a mail exchange with Locosys: they confirmed me that the GT31 should come to its end of life "soon". They also mentioned that they are preparing a successor for the GT31... I hope it will look like a waterproof solid watch, with all the GT31 features inside...
I had also a look to the waterproof Trace Module, made by Active Replay (US) (www.kickstarter.com/projects/activereplay/trace-the-most-advanced-activity-monitor-for-actio) which will log every second the GPS position and the Doppler Speed in a GPX file. I will receive a beta version of Trace next month and test it... The Trace module can also be used with iPhone and Android Applications to get a complete analysis of movements (jump heigh...)... VERY promising and interesting product...
For now, I keep use my GT31, because I need the Doppler!
