Snipped from the "Aquapac location" thread -> a new thread seemed more appropriate:
quote:
Originally posted by Roo
We may not like the accuraccy levels that the WSSRC have set for GPS record ratification but they are the recognised authority representing the International Sailing Federation and any record claim has to have their blessing. It is possible to meet their criteria with off the shelf units but the cost of such equipment is not economically viable at the current time.
- they have a requirement for "positive buoyancy"... What about locations where it is only 3 feet deep across the whole body of water; you can stand up everywhere, you don't need to be positively buoyant.
Mathew people have been known to drown in a bathtub, speedsailing, particularly record attempts, is a dangerous pursuit. Take a big fall and the chance of drowning is greatly increased especially if you have 10 kg of lead on your back. Having some buoyancy may not save you but it does increase your chances of survival.
- they require a "three month pre-notification" of a possible claim. WTF? If it is windy on the weekend, I want to make use of that wind.
There is nothing to stop you sailing and making use of the wind but if you want to make an attempt on the world speed record then some infrastructure has to be in place to ratify and observe the proceedings to make sure they are legitimate.
- paying them may thousands of pounds/dollars just for the sake of an observer. Is an observer required? sure, but why do they need to fly out to ... (pick your country) - why cant we use a local representative?
You can use a local observer, that's what MI do at Sandy Point, they don't fly one out from the UK for every attempt.
- wording of the rules so that only Trimble is allowed to be used is simply pandering to the expensive end of the market. Trimble make great stuff, but $10,000 is a bit much do you think.
It may be expensive but it is accurate in position to within 5 cm and does record data 10 times per second. No recreational gps even approaches those levels of accuracy.
Part (most?) of the reason that speed sailing disappeared from windsurfing was that it was useless holding any event while trying to comply with the WSSRC rules. Now that run measurement is easy (removing the obstacle of needing to outlay $$$, stupid rules and video timing), as the last two years have shown, the sport will grow again.
I think the real reason speed sailing competitions died is because it wasn't possible to break the world record at every event and that was what the press and the sponsors wanted. Take away the publicity generated by a record and no sponsor wanted to be involved. Speed sailing never died, it continued on quietly at the same locations, with the same sailors, there was just no big events. Ways were found to time events and the advent of the portable GPS made timing more accessible. Most speedsailors are more interested in their own personal record, the very small percentage that pursue the "World Record" have attempts and events that cater to their needs. Speedsailing has become more democratic with access available to a greater percentage of sailors than ever before. The team challenge is just one example that brings sailors together all over Australia in a common pursuit, I don't think it makes any difference that it is not run under WSSRC rules. As long as every one knows the rules they are playing by there never seems to be any problem. Sailors can compete using cheap off the shelf gps units and know their results will be accurate enough that no sailor has an unfair advantage or is disadvantaged by not having the latest or most expensive gps.
The WSSRC has their place and control any claims to a official world record. I'm sure someone will set up a "doppler" speed record body to administer their records but will it be relevant, I doubt it but that is just my opinion. Whether it be land speed records, track and field records, sailing speed records, they have all been records measured over a set distance that has been accurately measured to cm levels. Changing every method of measuring speed records to "doppler" and proving the accuracy will be a tall order indeed. I wish you and your techincal team all the best in your attempts to do so.
"...there is no reason why a more appropriate body couldn't be setup to represent the non-million-dollar sailing fraternity"
The WSSRC have been doing this before windsurfing existed. They are recognized by the ISAF as the only body responsible for sail speed records. We are talking about speed sailing. If you want to exclude the internationally accepted body from your record attempts .. what crediblity do you have.
"- they have a requirement for "positive buoyancy"... What about locations where it is only 3 feet deep across the whole body of water; you can stand up everywhere, you dont need to be positively buoyant"
Are you serious? The speeds involved are 90km/h. Former world record holder Eric Beal concussed himself in a stack on the canal. It's not very deep but he could have downed as can anyone in 3 feet of water if knocked out and weighted with lead without compensating bouyancy.
"- they require a "three month pre-notification" of a possible claim. WTF? If it is windy on the weekend, I want to make use of that wind"
A reasonable request. Anyone serious about making a record attempt will be preparing long before 3 months. You can book a 1 month time period and have the observer on call for when the wind is suitable.
"paying them may thousands of pounds/dollars just for the sake of an observer. Is an observer required? sure, but why do they need to fly out to ... (pick your country) - why cant we use a local representative"
You obvious haven't thought this out. How can you make any valid claim without an independant observer?
"wording of the rules so that only Trimble is allowed to be used is simply pandering to the expensive end of the market. Trimble make great stuff, but $10,000 is a bit much do you think."
If you are willing to organise the appropriate independant testing of the measuring devise you wish to use like Maquarie Innovation did then perhaps you could use another gps. Or you could just hire a Trimble 5700.
Having just read GPS Speed Surfing's technical committees recommendations, http://nujournal.net/Recommendation.pdf , I can now understand why they wont be sending the WSSRC any Christmas cards this year.
It seems they feel their "GPSdoppler" method of measuring speed is far superior to that currently used to approve speed records.
What I still don't understand is how you can compare measuring speed over a surveyed course of 500m with measured "doppler" speed in relation to a satellite with no proof of position.
They also seem to forget we deal in the here and now. "We also found strong evidence that in a few years the GPS-Doppler speed measurement
accuracy is likely to be improved 10 times"
This is the bit that I'm sure will make the WSSRC feel all warm and cosy, "In view of the above, an organization that chooses to disregard or disallow the GPSDoppler method of speed measurement in favor of less accurate methods could risk losing its relevance and authority."
It certainly makes for interesting reading and certainly reinforces YoYo's statement, "The WSSRC have been doing this before windsurfing existed. They are recognized by the ISAF as the only body responsible for sail speed records. We are talking about speed sailing. If you want to exclude the internationally accepted body from your record attempts .. what credibility do you have."
From the PDF:
Incorporating sufficiently long CRC check
(128 bit or longer) or other adequate digital
certificate inside the GPS-Doppler data log
file for the purpose of detecting any data
tampering.
This will never be 100% secure, because the competitor has access to the file. Any key/algorithm can be broken given enough time and resources, so there will always be some element of doubt.
Another problem is the fact that a competitor could change the firmware inside their NAVI, which could easily inflate their doppler data by, say, 10%...
I don't believe that doppler data has sufficient error correction in it either. For example, if you get a bad reading in Lat/Long track it's easy to figure out that it's bad data. But errors will accumulate if you're using doppler data, so it doesn't automatically take care of errors.
I appreciate what the gpsss community are trying to achieve, however I think they need to do a bit more homework.
cool, so when are we upgrading our firmware nebbian.
finally teamSEQ will win!!!!!!! 
The criminal mind at work
My sister did say any size estimate from Gestalt
should be treated with caution
However she agrees he is very quick
quote:
Originally posted by yoyo
Yeah .. not 'til Friday at least, eh elmo
Quote:
".......... however I think they need to do a bit more homework."
Neebian, this one smarts a bit. If you knew of the countless hours and huge efforts that have been put into this by a group of very cluey and dedicated people over many months you may be surprised.
The handling of the data from a GPS unit can be done just like it is with a Trimble survey GPS. It is the chain of handing that provides the level of security. The accuracy of the firmware in the Unit can be confirmed by the manufacturer or by another technical testing body.
A WSSRC observer is just a person appointed by them (presumably on the recommendation of the local branch of the yachting association). I am sure there are equally respected and trustworthy people who could be appointed by another body. (A couple of your competitors for instance are probably going to be watching very carefully :)
There are always going to be reactionary people who will argue that just because it has always been done a certain way in the past (probably because it was the only practical way available) then it MUST be done this way forever after, regardless of advances in technology. I am sure this argument was had when light beam gates were introduced to replace a posse of stopwatch holders, and again when video cameras were introduced, and again when MI proposed using GPS etc, etc.
There are also people with vested interests in other technologies or political/financial interests who will try to discredit new ideas or ways of doing things that threaten their personal interests.
The other group who will question a new method will be those who have an interest in records set under different conditions, be they natural conditions or technical conditions. This last group must be considered very carefully and their concerns evaluated as fairly as possible. Eg: is it fair that so and so got to run in a man made canal when I had to run in a public harbour? Is it fair that so and so was able to run in gale force winds when all I had was a gentle breeze? etc. One has to make a judgement based around a wider view of what is trying to be achieved. In this case, if it is for a manned craft to go as fast as possible on water with just wind power to drive it then the other factors become irrellevant. The only factors to be sure of are the SPEED for a minimum distance, the human was controlling it, it was on water and it was powered by only the wind. If the speed can be measured and confirmed with a high degree of accuracy and within a known error range (every system of measurement has an error range) then, in the end, the actual method used is irrelevant.
Mat was right about one important thing though. The WSSRC is just 'a' body that ratifies records. If they fulfill the needs of their clientele, great! If they don't then it is almost certain someone will come along who will do what they can't.
I'm sorry Sailquik, I didn't mean to imply that the team hadn't put in a lot of time and effort.
The "Error of Measurement" idea sounds fantastic, and would work well.
I guess the thing is that I couldn't see how the new system would work, from go to whoa, including how the data gets from the device to the record keepers, without the possibility of it being tampered with. This includes having suspect firmware loaded into the NAVI.
btw at the end, shouldn't "Transverse" be "Longitudinal"?
If you want to claim a World Sailing Speed Record then the WSSRC, under the auspices of the ISAF, is the only group that can provide recognition. If you want a Guinness record then contact them and see if they will recognise your speeds. If you want a "Doppler" World Speed Record then you are SOOL, nobody recognises you other than yourselves. The nice blokes over at GPS Speed Surfing may recognise the record but does it really mean much? Also recommending a GPS unit that has bugs in every version of it's firmware and switches off depending which sd card you use is not confidence inspiring let alone a good basis for claiming world "doppler" speed records. Lets just accept the GPS units for what they are, fun little toys that give us a good idea of how fast we are going which we can compare with other like minded speed sailors. We're not racing for sheep stations, it's all just meant to be fun. Silly question of the day, would you claim a GPS Doppler Speed Sailing record or a GPS Doppler Speed Surfing record? Inquiring minds want to know.
Doppler is particularly good at measuring speed, which is why it is used by car manufacturers and racing teams rather than a trackpoint location based system. They and we dont need to be particular to the cm about where the speed was achieved. What is important is how fast we went and how accurate those measurements are.
GPS units like the Locosys GT11 generates the doppler data we need to achieve this significant accuracy. The results are output every second, not every ten seconds, but 10 recordings per second does not make the result more accurate. Only more often! However ten recordings per second would be vastly better at capturing fine detail movements like recording turns and jumps, which is why we are keen to get support for 10hz doppler. The SIRF chips measure doppler ten times per second now to calculate the one second outputs, so its technically possible with the current hardware to generate 10 hz output... Yes it will rival electronic timing, yes the performances will be beyond question, and yes the opportunities will be amazing!
I urge everyone to look past the hecklers and make up there own minds about what this technology offers. It is a fantastic opportunity to open up speedsailing and sailing in general with many new ways to have fun, like Alpha Racing, that will enhance our enjoyment of the sport.
Roo, I think that anybody who covers a distance of greater than 500 metres at an average speed higher than others to date can lay claim to holding a World Sailing Speed Record. It becomes merely a question of verification and recognition. The "Doppler Committee" seem to be working towards an acceptable verification protocol within the current limits of technology, wether they are there yet or not is probably still open to debate. However, it would be greatly dissapointing and the sport would be diminished if the upper limits of speed are constrained by the verification process rather than the limits of sailing ability. The present WSSCR rules appear to close to the limiting factor at present. Before too very long I suspect that a GPS wearing kitesurfer or windsurfer WILL cover a distance of greater than 500 metres at an average speed of greater than 48.7knots. It will then become a question of verification and recognition. Clearly verification will not satisfy WSSCR requirements and therefore WSSCR recognition will not occur. This will make any future WSSCR compliant efforts farcical as others will have already been faster. If the average speed can be verified according to the "Doppler Committee" rules or in some other forum (court of law?) then it will be a question of recognition. This is where the WSSCR is in danger of becoming irrelevant. ie who recognises the WSSCR and ISAF. If these august bodies have a closed mind to what GPS has to offer then it is they who risk losing recognition. After all there are several boxing authorities all of whom have a world champion. It would be a great shame if we had to have a World Sailing Speed Record recognised by WSSCR and a separate World Sailing Speed Record recognised by the GPS community but it would be a TRAVESTY of justice if the fastest person under sail was not recognized because of limits to speed measuring technology.
A personal view of the subject.
Frant
You make some valid points Frant. Of course the general (ie non-sailing) community is becoming very familar with the uses and potentials of gps , if not the workings or history of it through the ever increasing exposurure in cars, personal navigators and mobil phones. And this exposure will increase exponentally. Given the minimal cost of having a logging device capable recording a years worth of travel at 1 second interval (Navi with 2G card) it is hard not see such units being standardised/mandated in cars in future.
Goverments will say it's cheaper than cameras for such things as London's congestion charge or Melbourne's City Link tarriffs. Police will point out the benefits to them as will accident authorities (black box). Car makers will imply numerous benefits and other owners (jealous spouses, worried mothers) will see others. Of course the civil liberty unions will complain..and they will be as effective as they were at keeping video cameras out of cities.
The point is, drivers will challenge their speeding fines when they realise the units in their cars are much more accurate than the multinovas. Once in court, the accuracy will have to be officially checked. Once verified in a court of law as an accurate velocity measuring device, a device in common use in the general public. Then a speed claimed in a well publicised/promoted event ( but not WSSRC santioned) may well be accepted as valid in a publics mind now familar and comfortable with the amazing accuracy of these tiny devices. That is something the WSSRC may need to keep an eye on. Technology may sideline them.
"which is why it is used by car manufacturers and racing teams rather than a trackpoint location based system."
Again you seem to miss the whole point, they are measuring speed not claiming a speed record. In Formula 1, the pinnacle of motor sport, they record the time to complete a lap and an average speed over the distance of the lap. The speed is derived from using a position, ie start/finish and a track they have to drive on. It is not derived by reference to satellites in orbit. They don't record a doppler speed for the lap at all. What is important is how fast they went over a set distance, ie the full lap and where they achieved it, ie the track and how accurate those measurements are.
GPS units, whether the NAVi or any recreational unit, cannot generate the data to measure a distance accurately or prove where the measurement occured. Try proving that in court.
"The SIRF chips measure doppler ten times per second now to calculate the one second outputs, so its technically possible with the current hardware to generate 10 hz output..." Again your data seems to be somewhat suspect as you have no proof in either the nmea output or binary output that the doppler is measured 10 times per second, all you have is approximately 1 second readings. You may want to check those also because I can guarantee they do not occur at exactly 1 second intervals!
"Yes it will rival electronic timing, yes the performances will be beyond question, and yes the opportunities will be amazing!" It's amazing how confident you can be in something that cannot be proven and has no credibility for claiming official records.
"I urge everyone to look past the hecklers and make up there own minds about what this technology offers. It is a fantastic opportunity to open up speedsailing and sailing in general with many new ways to have fun." It's amazing how we are hecklers when we point out the deficiencies of system which was never designed for record breaking and doesn't have the capabilities. The recreational GPS has already made speedsailing more fun and accessible, why try to complicate it with new rules and regulations which cannot be proven and do nothing to for the recreational speedsailor.
quote:
Originally posted by Roo
"which is why it is used by car manufacturers and racing teams rather than a trackpoint location based system."
Again you seem to miss the whole point, they are measuring speed not claiming a speed record. In Formula 1, the pinnacle of motor sport, they record the time to complete a lap and an average speed over the distance of the lap.
To me all this, is, is semantics. If it was left up to the WWSR then speed sailing would still be where it was 10 years ago. Setting world records is expensive and time consuming and must be beyond seconding the results. BUT as this technology improves it MAY replace the current system as electronic timing replaced stop watches. A the moment you could get a Garmin/Navi etc “World Record” if you want and we sort of do this via the GPSS Web site which is recognised by our peers Let’s just get on with sailing fast, having fun and comparing apples with apples. The GPS lets us race in new ways that weren’t possible 5 years ago and if you want to break records you can go and do it with the current recognised system. Lets face it most of us aren’t going any where near 50kts .Lets use these systems to improve our sport of speed sailing and having fun. Now can someone come up with a 100% reliable wind predication, a month in advance please?
Doppler is a highly effective system for measuring speed and has the potential to be more accurate than current video timing or timing through eletronic gates.
Even the WSSRC dont care too much about where the speed was achieved because they allowed unfixed gates for MI. Using simple consumer GPS the location can be determined to within 25m. There is no purpose or benefit to determine a more exact location because location is not the basis for the speed measurement. And I doubt if any system could prove an exact location, so it becomes a mute point.
And here is some analysis from NASA on GPS for tracking spacecraft. The speed errors correlate very well with work done by Tom Chalko and Manfred ****hs.http://geons.gsfc.nasa.gov/library_docs/Fmt97gps.pdf
Hi Nebs.
Yep, Mal is not really a close follower of motorsports 
and they don't tend to use this stuff as much in circuit racing but it is widely used for testing in some areas of motor sport. I understand it is used for sports and road car testing a lot. See this link and check out the data logger.
www.racelogic.co.uk/index.php/en/?show=VBOX-Products-VBOX_Mini
I just love those suction cups
Out of interest, what difference in readings is one likely to get if one were to put a GPS on each arm? What's a reasonable figure that people normally get?
"Let’s just get on with sailing fast, having fun and comparing apples with apples. The GPS lets us race in new ways that weren’t possible 5 years ago and if you want to break records you can go and do it with the current recognised system. Lets face it most of us aren’t going any where near 50kts. Lets use these systems to improve our sport of speed sailing and having fun." Kato you summed it up perfectly, it's all about having fun...let's leave all the bs and politicing to the politicians. There will always be groups of people who want to control everything and dictate how things are done, at the end of the day they and what they do become irrelevant in the grand scheme of things. Stirling Moss once said, "if you're in control you're not going fast enough."
Yes Nebs, I have done quite a bit of side by side testing with GPS's. The very first thing I discovered was that with the Foretrex the results varied so much it alarmed me. It suggested that if we run a competition with them the variation/error in them could easily cover all the top placings meaning that it was almost meaningless. The difference between units worn side by side was often more than .2knot. That might not sound like much at first, but take a look at the GPS-SS rankings and see how many riders that can cover, especially in the middle rankings.
Most of the problem was from the grid effect because of the way the Foretrex (and Geko) clip the precision of the saved data to save memory space.
This set some of us looking for a better GPS and we found that the Garmin Edge and some others do not clip the results and gave more consistent results. Then we discovered that the Navi/GT-11 is capable of outputting NMEA data which contains extra information on the accuracy and reliability of the signal. Roo had a major part in this discovery and deserves much credit for this.
The result was that we had improved accuracy and the information to be more confident of that accuracy. Side by side testing revealed that the difference was now mostly much smaller and more consistent.
Now we reconed we had a tool that could provide much fairer results for GPS-SS type rankings and especially for speed competitions. As I understand it, Roo then expendeed an enormous amount of time and energy trying to find a way to process the info from the GT-11 in such a way that it would be even more accurate with the idea that it may be able to be as accurate enough to meet WSSRC standards. It seems this was not to be.
Then Tom Chalko suggested that that such accuracy should be able to be had by taking a different approach and using the Doppler calculations rather than trackpoints. He reasoned that this was potentially very much more accurate than the trackpoints since it didn't have the same vulnerability to changing atmospheric conditions and would not require extensive post processing. The accuracy can also be proved to a known level using the underlying science.
Now we have a method that can be used for competitions and we are able to be very confident that close results are ranked correctly. Sise by side testing shows consistency to closer to .02 Knots. For me that is the most important aim. The spin off is that anyone who does happen to go close to or exceed a recognised Record can be very confident of the comparison. The whole question about whether the WSSRC will recognise this method of speed measurement is another matter and is best left up to anyone who wants to put a proposal to them. But the statement that this method of using Doppler is as accurate, or more accurate than Video timing is demonstrably correct and it is also true that the WSSRC sees video timing as accurate enough for their standards. The rest of the arguments and speculation are just that, speculation, and..... politics!
I think all the work that Kean put in to use GPS for setting records was the right way to go, and did us all a great service for doing so. The only difference between Keans work and ours is that the technology we are exploring is more suited to measuring speed than the position based systems that rely on two locations.
The work being done to validate this technology will benefit all sailors from those that just want to improve their sailing to those that want to break records. Its about making opportunities for sailors that the current systems dont provide.
Just a small correction to Daffy and Mal's comments, I had recognised the importance of "doppler" speeds long before Chalko had even become involved in the project or even used the units. I asked Mal early last year to incorporate "doppler" speed and calculations into RealSpeed as it was a much more accurate way of measuring instantaneous speed. My aim was to combine both trackpoint accuracy with the "doppler" speed by boosting the data stream out of the units in binary code to allow post processing to WSSRC record levels. All my research showed the NAVi isn't stable enough to do this and the errors produced by the units aren't constant or provable to allow the necessary levels of accuracy for record claims. For a competition situation where every rider is using the same unit with the same firmware and the same sd card recording nmea data, there is a very high level of confidence in the results. The nmea data they produce provides all the information we require to confirm the results, the binary output is still too unstable to be trusted and has the adverse effect of causing voltage spikes during computation cycles that causes failures with certain sd card that have sensitive voltage requirements resulting in the units shutting down.
