I am not sure it's a given that satellite time and UTC time will always be exactly the same........
I am pretty sure a good timepiece watch will probably hold sub second accuracy, once set, for quite some time. 
Select to expand quotePaulvN said..
Hi All, I am just an amature Windsurfer and I wan't to give my Son a GW 60 for his birthday( he is going to do the Slalom races in Holland)
I see a lot of questions and solutions in this group.
I've got a simple question: Do you advice to buy the GW60? or should I wait
If he does GPS sailing and wants to post results on either GPSTC or GPS-SS, then the GW60 is the go. Its waterproof, accurate, easy to use. In addition, with the coming new firmware, that is currently being tested, it has some great new functionality.
If he does Slalom racing then the GW60 will also be really good to measure and compare straight line and gybe speed during training sessions. He will still need a separate timing watch for race starts. The timer on the GW60 does not have good enough visual and sound feedback to nail a slalom start
jn1,
Further back on this thread, your very subject came up, about page 9 I think.Select to expand quote
A completely different GW60 Topic: Watch time accuracy?
My understanding is that the 'clock' feature obtains its' time from the GPS, according to the instructions.
Someone please explain to me why I have a GW60 and a GW52 that were both used today obtaining GPS speed data and yet their clock times are different by 2 seconds! I would think that every time the unit connects to the GPS satellites that it would re-sync, no?
Not really a big deal since I don't use either as a 'time piece', but was surprised to see this.
Select to expand quotedecrepit said..ka43 said..
>>> I know the gurus will poo poo my comments but it just seems the "great fix" we were all waiting for isn't really happening. >>>
No mate, a watch was never the favourite option, it's got smaller everything, antenna, memory and battery.
And the wrist is not an ideal place for GPS accuracy.
But I assume the marketing gurus decided that what would sell the best is the watch.
I'm sure this is a marketing decision, not a technical one.
As so often happens, it may sell more units, but it's not ideal for the purpose.
So basically the fault is down to consumers who listen too much to marketing hype and follow fashion for fashions sake. If everybody considered best for purpose before buying, the marketing guys wouldn't have so much say.
Woops, maybe the physical memory size is smaller, but the watch has much more capacity, probably a few days at 5hz.
I did a 100km with the watch yesterday. It had about 1/4 of bar of battery life left at the end. 100km is more than enough for me. My inner battery will run out before the watches battery.
Beat you John, 
I did 120km on Tuesday, but I charged the unit up over lunch and board change. I had 2 bars left when I came in.
But it was far from a good distance day I was on the water for about 8 hrs, enough time to do well over 200kms.
Does this mean my internal battery will get better as I get older. Your a champion Mike. I was ready to go in at 78kms, but I thought I'd might as well bring up my century. I didn't really enjoy it.
Select to expand quoteJohn340 said..
Does this mean my internal battery will get better as I get older. Your a champion Mike. I was ready to go in at 78kms, but I thought I'd might as well bring up my century. I didn't really enjoy it.
Probably not, I think conditions have a lot to do with it. Go to Lake George when it's really on, you'll be surprised at how far you can go. Flat water steady wind.
Although I say it wasn't a good distance day, that's because I'm useless in chop, and the 2km run had the boat channel in the middle which was choppy. So I stayed on one side most of the time and just did 600m speed runs, in flat water.
I think on distance days I'll carry my GT31 as well and just use the GW60 when going for a casual sail with no PB's in mind.
Select to expand quoteJohn340 said..PaulvN said..
Hi All, I am just an amature Windsurfer and I wan't to give my Son a GW 60 for his birthday( he is going to do the Slalom races in Holland)
I see a lot of questions and solutions in this group.
I've got a simple question: Do you advice to buy the GW60? or should I wait
If he does GPS sailing and wants to post results on either GPSTC or GPS-SS, then the GW60 is the go. Its waterproof, accurate, easy to use. In addition, with the coming new firmware, that is currently being tested, it has some great new functionality.
If he does Slalom racing then the GW60 will also be really good to measure and compare straight line and gybe speed during training sessions. He will still need a separate timing watch for race starts. The timer on the GW60 does not have good enough visual and sound feedback to nail a slalom start
Thanx
Select to expand quotedecrepit said..
That was my point, about accuracy, I've no idea how often it checks the sat time. Once it's synced on initial start up it seems to just run as a watch, GPS signal or not.
Woops revise that, I've just turned it on after several days off and its about 1hr 30min fast. After it's synced it agrees to the second with this computer.
If I could remember just how long it's been off, we could work out how long it would take to be over a second fast, hmm probably not long at all maybe two days. So if it isn't checking the GPS signal regularly it gains 1.5hrs in 48, or 1hr in 32 or 112sec in an hour? That seems like a lot, am I doing this right?
The device-local "clock" in a GPS device, is usually implied to be the Crystal-oscillator (TCXO) or similar - this thing needs to be super accurate, or your GPS wouldn't be able to lock onto the GPS carrier.
In devices that are wrist-watches showing the local time, there will also be some electronics which attempts to "keep the local time" -> since they are rather cheap components, they aren't too accurate... so the local time tends to drift. [ You have one of these on your PC - if you have it disconnected from mains-power you tend to not notice this as they are often accurate for months - but I have seen some PC's drift 5 mins per hour. A modern PC will use "NTP" to resync to an atomic clock. ]
The GPS system sends down time-codes accurate to about 10 nanoseconds -> whenever you get a GPS-lock, the local time will get updated to the GPS time-codes Obviously a cheap GPS cannot do 10ns accuracy - we tend to see only a few decimal places of accuracy... but some GPS's devices are capable of using the time-codes to be quite accurate [ Indeed you can build yourself a stratum-1 atomic clock for about $20. ]
It is my understanding that GPS time, although extremely precise, is not necessarily the same as UTC time.
To get UTC time a correction to GPS time may be needed to allow for the fact that GPS time has been running since the GPS system was initiated and UTC time has had numerous 'leap' second corrections. I think GPS time does get some corrections as well, but it does not nesassarily stay exactly up to date with UTC time.
Many of us have seen the 15 seconds difference between time stamps on various GPS's. Some have UTC corrections and some don't.
As Mat says, there are also some GPS chips that prioritise timing accuracy output for various scientific uses.
Select to expand quotesailquik said..
It is my understanding that GPS time, although extremely precise, is not necessarily the same as UTC time.
To get UTC time a correction to GPS time may be needed to allow for the fact that GPS time has been running since the GPS system was initiated and UTC time has had numerous 'leap' second corrections. I think GPS time does get some corrections as well, but it does not nesassarily stay exactly up to date with UTC time.
Many of us have seen the 15 seconds difference between time stamps on various GPS's. Some have UTC corrections and some don't.
That isn't entirely accurate - GPS and UTC are synchronised with the Earth's geoid -> they use the S.I. unit for the length of a second, which means they are exactly in sync from an "time moving forward" perspective.
The difference lies in the fact that GPS doesn't get any leap-second adjustments, while UTC does [ an exact S.I. second, and only when announced ]. GPS itself is offset a fixed SI seconds from TAI.
Select to expand quotemathew said..sailquik said..
It is my understanding that GPS time, although extremely precise, is not necessarily the same as UTC time.
To get UTC time a correction to GPS time may be needed to allow for the fact that GPS time has been running since the GPS system was initiated and UTC time has had numerous 'leap' second corrections. I think GPS time does get some corrections as well, but it does not nesassarily stay exactly up to date with UTC time.
Many of us have seen the 15 seconds difference between time stamps on various GPS's. Some have UTC corrections and some don't.
That isn't entirely accurate - GPS and UTC are synchronised with the Earth's geoid -> they use the S.I. unit for the length of a second, which means they are exactly in sync from an "time moving forward" perspective.
The difference lies in the fact that GPS doesn't get any leap-second adjustments, while UTC does [ an exact S.I. second, and only when announced ]. GPS itself is offset a fixed SI seconds from TAI.
I thought that's what I said? 
Status of Firmware upgrade:
Development and testing of the upgraded firmware has finished. Locosys are currently updating the operating manual and utility to suit.
The new functionality includes:
1) 4 speed genie screens that shows both the latest run compared to the top result for the session for the disciplines of your choice. Disciplines you can choose from are Max, 2 Sec, 10 sec, @500, 100m, 250m, 500m
2) Option to turn off 1 or 2 of the speed genie screens
3) An optional 5th speed genie screen that displays session distance, which can be displayed in either kms or Nm independent to the unit chosen for speed disciplines.
4) An optional 6th speed genie screen that displays the Time
5) Display by button touch of your top 5 x 10sec speeds and average in small and large font format
6) Display by button touch of your top results in all disciplines in both small and large font format
7) The ability to use the timer and stop watch while in GPS mode
8) A horizontal bar displayed in GPS mode that shows how much the set time in the timer has expired
9) The screen reverses colour when the timer expires
10) A Streamlined delete function
11) An optimized LCM screen redraw driver
12) Display by button touch of 2 GPS satelite reception screens
The public release of the new firmware is now in the hands of Locosys
That seems pretty good to me. Will the watch screen not go to sleep when not in gps mode?
Select to expand quoteDag said..
That seems pretty good to me. Will the watch screen not go to sleep when not in gps mode?
That's adjustable as well, via the "auto sleep" selection.
Sorry guys, here's a real tease, the trial release of the new utility.
the new feature have been added to settings. Auto sleep can be toggled off and on AVG NSEC is best for 10s as before because that's used for the 5XNsec result. the AVG MSEC is best for 2s as that doesn'te get a 5x average screen.
With the 4 RSLT adjustments I've set !A to 2s split screen, with last run and session best. If instead of "TOP" in the second selection I'd had "MSEC" it would be a single large font display of 2s, same for the 10s and alpha. But the 4A/4B 500m selection I've turned off to make faster scrolling, by selecting the "X" option, this is also available for 3A/3B. The "O" in RSLT DIST and RSLT TIME turns these windows on, they join scrolling action with the RSLT 1AB to 4AB. Then there's the unit to use for the distance read out. On the log data screen, there's a "quick log clear" button and it works very well!
Don't forget the 24hours clock-mode Really a perfect job by Locosys and the test-team !! Can't wait to see this version public !!!
I used the new utility this morning, downloading my session from yesterday. It works really well. I like the way you can save your settings configuration with the "Backup CFG" function.
Select to expand quoteJohn340 said..
>>> I like the way you can save your settings configuration with the "Backup CFG" function.
And also clone the rest of team so you're all doing the same thing.
Just had an email from Locosys, the public release of the new firmware will be on their website next week.
In the meantime it's here.https://dl.dropboxusercontent.com/u/10480954/GW60/GW60AR_Pack0314B_PR.rar
I'm not sure if the manual has been finished for the mods, so please post any questions here.
The watch is now very versatile, but more options make it more complicated to set up. And everybody will probably prefer slightly different set ups.
Due to hardware limitations, the watch can't do Nautical Miles or Hours, and the Alpha has a minimum length of 300m. If your alpha is processed by software with no min length you'll still get valid alphas under 300m, but they won't show up on the watch display.
Another limitation at the moment is the speed genie setting, for the alpha display you need to set it under the alpha min speed. This means it doesn't hold the "last run" numbers once you go over that speed. So optimally there needs to be two speed genie numbers, one in between the upwind and downwind speed sailing speeds, the other lower than your min alpha speed. This isn't possible with the watch as it currently is, so the number has to be changed depending on what you want.
I've found in practice I leave mine on 10kts, If I think I've had a good speed run, I stop at the end of the run to check. If it just isn't alpha conditions, then I might change it to 25/27 knots.
If in doubt try the settings I have above, and customise from there. The "BACKUP CFG" button will back up this config, so you can change what you want, and if it doesn't work just hit the "RESTORE CFG" button.
Select to expand quotedecrepit said..John340 said..
>>> I like the way you can save your settings configuration with the "Backup CFG" function.
And also clone the rest of team so you're all doing the same thing.
Hey, Skipper, thanks for all that info but..........does that mean I have to be a clone of Fangy or Elmo? Yeew!
Thanks John. My son Fergus just updated both our watches to the latest firmwear. OMG what a huge upgrade. I have been thinking the watch was OK but not brilliant. This is a big step forward, great work.....
Select to expand quoteSteve Charles said..
Thanks John. My son Fergus just updated both our watches to the latest firmwear. OMG what a huge upgrade. I have been thinking the watch was OK but not brilliant. This is a big step forward, great work.....
Great Steve! Glad you like it. I think it's been well worth the wait, to iron out the bugs, and improve it's usefulness to us.
Select to expand quoteAgree, big improvement, thanks to Decrepit and everyone involved in getting this all to happen. Used the GW60 with the upgrade yesterday and could see my last 2-second and 10-second score after each run, plus my best 2-second and 10-second run as well as distance sailed and the time. Brilliant! Just need best NM and best Alpha now and I reckon that'll cover just about everything.
