[GPS Team Challenge] Changes to the site?

I think the philosophy of the people's competition needs to be maintained, so it's what the people want.

However, Nebbs does this all for free, he has paid for Domain names, and it's his hardware, and whaever that gigs space talk means.

Maybe we look at a donation system which is voluntary, and those that can afford to donate to mthe upkeep and costs of website, can do so.

Nebbs, what sort of $ are we talking about, so that you recoup at least your out of pocket expenses, and what would ongoing costs be?


Re: website it's looking great the Rankings is brilliant, I wonder whether rankings by class eg Open, Master etc might be an additional way for people to get a top ten ranking?

Definitely agree with the fun factor. Though we can't stop the competitive nature in people.

The relationship building was another factor which already has occurred.

Re: Validation of sessions, yes was thinking that the top sessions should be made available for verification, and Elmo volunteered ages ago to be the quality control man.

But who are you cheating anyway..... really?

If you need or want some one to check then I can do it as is doesn't tend to take to long.

Don't go posting tracks to site as it is just wasting space.

Everybody should keep all their tracks on their own personal computers as the following file types.

Raw data (as the data comes from the GPS)
Edit Data (the file after it's been cleaned of spikes)
These files should have the date of the session in the name as well.

I have been checked a couple of times for my data by GPSS and it is painless process.

If it was wanted here then it can be simply done, but realistically we shouldn't have to as it is a friendly competition.

I think this thing is brilliant and thank all those involved for it. I am more than happy to chuck a few bucks at it to cover the costs of those who have incurred them.

I reckon this is only the start of something which could be huge!

Personally Nebs I think the 2 best results is great, gets the whole team involved, and introduces a bit of stratergy, working out who's going for what when.

I also think there's an issue with using different versions of realspeed, (and how it's set up) but I think there's a bigger issue between doppler and track results.

typically doppler will give .2 to .4 kn less than track in the 2sec division but gives a greater total distance.
(don't know how you can go further at a lower speed, but that's what my realspeed says).

Seeing how close some of the placings are, (we're down to .1kn differences at times), it would be good if we were all doing the same thing.

What if at the end of the month, all the scoring tracks are checked using the same method. If any came out lower, then those results would need to be compared again to see if they're still the best.

If everybody can do dopller I guess we should all use that, as it's meant to be more accurate, but if everybody can't do it then we should all use tracks, to keep it fair.

Hey guys,

Thanks for the responses. For the record, hosting costs aren't all that much, $200 a year would cover it, so if everyone put in $2 as an entry fee then it would pay for itself. I don't really want entry fees though, and a donation page looks tacky, I like having a free competition. At the moment I'm thinking that next year's major sponsor could pay for some hosting as well.

I'm personally not convinced that doppler is more accurate, simply because if your numbers are out by 5% in doppler you'll never know. However if your trackpoints are out by 5 degrees then it doesn't make a difference to your speed. But I'm sure lots of very clever people are working on it at the moment

Different versions (and setups) of RealSpeed is definitely an issue. I guess that's what we get for using cutting edge technology! We definitely need to standardise on one realspeed file (which I tried to do previously) and one version of RealSpeed.

From what I can gather, most people don't want all the fancy bells and whistles, they just want to download their numbers at the end of a session.

I'll see what I can do

quote:

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Originally posted by vando

you da man nebs

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b]From what I can gather, most people don't want all the fancy bells and whistles, they just want to download their numbers at the end of a session [/b]
Yep what he said (Nebbian) couldn't agree more. I am not a happy vegemite when I start mucking with latest versions of any program. It always turns pear shaped (most times I am just missing a vital point)and I have to go for help from those who probably have much better things too do than sort my software crap out
So a "load the bastard once and run with that would be flash like Michael Jackson

My nickname is "Bonehead", that says it all. I have been struggling with my Navi since I purchased it and have encountered every problem possible....but not any more! Firmware ver. 914a is the answer. Once set up- big digits for speed and max. speed, no toggle to reset, just double click, and lots of features I don't want or need, but there for those who are that way inclined. Get it (or have someone who knows how to) before they change it again.

Hey Roo,

The problem you're describing is the 'speed genie' I think. It's supposed to show you what you want to know, but according to Tom Chalko's site has unresolved bugs as of now.

Turn the genie off and you'll be set.

The Binary data from the GT-11 is the one to use. No binary data in the old firmware! Use the latest or at least a version that gives you the Binary data.

Of course there have been some bugs in the newer firmware versions. These have always been admitted to and fixed very quickly. Many things that are reported as bugs actually turn out to be simple USER ERROR!

Binary data from the GT-11 contains both trackpoint and Doppler data. The trackpoint data in the Binary files is much higher resolution (accuracy) than that in the NMEA data. We should be (and are, I believe) using the trackpoint data for posting on both GPS-SS and GPS Team Challenge. GPS-SS is aiming to switch over to Doppler data (which is arguable 10 times more accurate) derived results for 2008. By that time this current team challenge will be finished. If a new team challenge starts up for next year we should definitely switch to Doppler data then.

As to issues with setting up RealSpeed: Mal has available for download on his website rsp files that are preset for various competitions. Simply open the correct rsp and then download your data and run RealSpeed. Get results. Thats it!

As long as the version of RealSpeed you are using is binary enabled (v1.901 onwards) it does not make any difference which version you use. The results are the same in the end. I have run the same files in all 12 (!)from 1.601 to 1.918 versions I have on my desktop and get identical results from each.

quote:

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Originally posted by nebbian

I'm personally not convinced that doppler is more accurate, simply because if your numbers are out by 5% in doppler you'll never know. However if your trackpoints are out by 5 degrees then it doesn't make a difference to your speed. But I'm sure lots of very clever people are working on it at the moment

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Doppler is essentially measurement of carrier frequency, which differs from the expected frequency, ie: in it simplest form, the 1.2GHz expected signal is subtracted (mixed) from the actual satellite carrier -> the difference is a 1:1 relationship with speed. Thus resultant frequency is a few hundred Hz or so. At this frequency we are very good at high-precision measurement (eg: think high quality audio). Now do this for each satellite, then average.

Compare this with...

Decode the bit-stream from every satellite, then apply the ephemeris and time-code to an elliptical earth model. Now generate a lat/lon for that time-code.

Basically using a model and doing computations is far more complicated than simply measuring the frequency difference.

Also importantly for doppler, some of the causes of error can be measured in real-time (atmospheric effects, relativistic effects, devices tolerances), so that you are able to more accurately determine the final error of that data-point.

As for the 5 degree thing -> this is one of the biggest cause of error when measuring speed between two adjacent trackpoints, ie: the first point might be 5 degrees out but the second point will probably be the same magnitude but opposite direction. Then the third point is opposite direction again, and so on. So the speed error is cumulative.

The best example of this is what we have coined the "grid effect" on the Foretrex. The low resolution lat/lon effectively causes the point to have larger error per angle as the point can only fall on a 2.5m grid.

Note that the grid effect as we know it in windsurfing, is due to lack of precision, but the lack of high-precision capability is the reason why trackpoint data is not as good as doppler.

Of course, most GPS's built in the last 10 years has focused on "position on earth" for lat/lon (aka trackpoint) - probably mostly due to the power of moderm mapping GPS's. So it is possible to produce higher resolution doppler by making the frequency difference measurements more accurate.

Hopefully this helps to explain...