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MartinF2 said.. AUS4 said..
So let me get this right.....no other watch works when sailing with an under arm grip but this one does ????
Rick I'm not sure it's about antenna position but more the fact the GW-60 seems to be the only watch that can record data in DOPPLER format which makes it different to anything else available. This alone suggests it's a genuine player for our sport so our numbers can be verified from this critical information that is recorded. Obviously this is all yet to be tested but it's basically is the GW-52 in a watch format which is what we have all wanted for so long now. Not sure where all the negativity on this thread has come from? This is looking like the exact thing we all wanted - finally.
The GW-60 Log Record includes: UTC time, position, altitude, Doppler Speed over ground,
Doppler vertical speed, satellites used, Standard Deviation of Speed (SDOS) Speed sample resolution: 1 cm/s
SDOS resolution: 1 cm/s
Typical accuracy of 10s average speed measurement: ~3 cm/s, 99.7% certainty
Accuracy of specific measurement can be determined from SDOS of speed samples used to compute average speed.
I can't see any other GPS watch currently available that has this information to confirm the accuracy of our divisions. I'm happy to stand corrected.
Cheers
Marty
Pretty well spot on Marty.
The GW-60 antenna is the same antenna as used in the GW-52. It is in the watch band and is a proper patch antenna which is 10-15 times better in signal gain than a typical watch or smartphone chip antenna.
There really is not any complex accuracy testing required for the GW-60, as it is the same hardware, and mostly the same software as the GW-52.
That hardware and software has already been comprehensively tested in controlled conditions and it's capabilities are well known. This was mainly done by Dr. Tom Chalko and was no small task at all. It took him many weeks and a great deal of effort and skill, to say the least.
Briefly:
First, multiple devices were subject to geostationary side by side testing. This can give us the actual accuracy range but it relies on all filtering being turned off. (not possible with many devices)
The GW-52 was then put then through hundreds of km's of controlled side by side moving testing with 6 devices. All the devices are all mounted with the same sky orientation and fixed on the same plane. The millions of data points were run through software that compares every single point with the same time stamp for all devices to quantify variations, and compares that to the reported Doppler error values.
This does a number of things.
It validates that the real results are within the reported error values and it finds the frequency of any values outside it (if any). It also gives significant data of the possible variation between devices. It does this over varying atmospheric conditions, satellite constellation patterns, satellite numbers, varying speeds within the windsurfing target range, varying accelerations and in different directions.
One key aspect of this is that all the data is validated against the reported error values ('SDOP'). This means that in actual stand alone use, the SDOP value can be used in reverse to validate the data generated. This last step is the key reason why we can not have the same confidence in any data generated from non 'SDOP' devices, even after similar extensive testing. We might have statistics of the tested error range and frequency, but we have no way of knowing when any individual result is within an acceptable range. In effect, that is what SDOP tells us.
That data has since been confirmed in many real life windsurfing side by side tests, again in carefully controlled conditions.
The GW-60 will be tested to see what effect wearing it on the wrist has on the integrity of the data, the magnitude and rate of errors. It will be worn in different positions and compared with GW-52's worn in the standard positions on the head and arm. We will of course, also test multiple GW-60's worn side by side in various positions. It is possible, and perhaps even likely, that in some situations with wrist wearing, (such as Alphas for example), we will see an increase in errors, and possibly errors that are outside the filters of the analysis software that cause some results to be rejected. We will be looking at the extent and frequency of any such errors and this may or may not lead to some recommendations for use.
This is one area where enthusiastic sailors can possibly help us to gather data. All you would need is a GW-52 and a GW-60 (or two GW-60's) worn as requested and some careful recording of that, and conditions, for each session.
Edit: If anyone is particularly interested in more details or clarifications of what I have written above, Please PM or email me. Please do the same if you wish to offer your help for testing when the devices arrive and the time comes.