Forums > Windsurfing   Gps and Speed talk

Realspeed Settings

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Created by Paul Kelf > 9 months ago, 24 Sep 2012
Paul Kelf
WA, 678 posts
24 Sep 2012 11:10AM
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I have 2 versions of Realspeed & both have different settings.
One is a very early version which I checked for a comparison.
I don't ever remember changing these settings & other people also have different settings agian.

Can anyone advise the correct settings.

It's a bit of a worry as I'm not sure everyone is running the same settings.



lao shi
SA, 1313 posts
24 Sep 2012 9:04PM
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Max HDOP of a 1000 looks suss and surely the min Sats should be 5+ so that you always have a fair signal not 0
Stop run speed I have as 7. Not sure about this but don't think it matters too much as long as it is not above planing speed.
I am running 1.928 which I think I downloaded as the GPSTC setting file
http://www.intellimass.com/RealSpeed/1.9/GPS%20TC%20GT.exe

Froude
WA, 20 posts
28 Sep 2012 10:18PM
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With DHOP set to 1000 and Min SATS set to 0, it means the invalid data filter in realspeed won't work and inaccurate data could be used to calculate the division results. DHOP should be less than 2 though I think the default is 4 and Min Sats should be 5+.

Perhaps if you had some bad tracks but still wanted the divisions to work, you could up the DHOP and lower the Min Sats?

Interestingly a stop run speed of 0.85 also stops the alpha division working. No idea why? It seems to work again once you get up near 2 knots.

paddymac
WA, 937 posts
28 Sep 2012 10:45PM
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Paul,

Looks like I have the same settings as you, can't remember where I got them from. v1.928



paddymac
WA, 937 posts
28 Sep 2012 11:02PM
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Getting the files from gpsteamchallenge.com.au/pages/guides

Basic looks like this



and advanced looks like this



Froude
WA, 20 posts
28 Sep 2012 11:17PM
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Nice work Paddy, seems to be the likely origin (the default.rsp files)

Still think a Min Sat of 0 and a high HDOP is circumventing the invalid filters. Plus a run end speed of zero definitely stops the alphas working on my realspeed.

Paul Kelf
WA, 678 posts
29 Sep 2012 11:06AM
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I am still confused.

The "stop run speed" actually affects Alphas which was why I started investigating.

I am assumining the settings from GPSTC should be what we all should be using.
Question: Why basic & advanced?

Where's all the brainiacs?

Maybe if I change the title to "boobs" it would get some interest

paddymac
WA, 937 posts
29 Sep 2012 11:50AM
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Paul, I think the basic and advanced has to do with the categories, basic has the six divisions and advanced has several more. But I think we can all see there is an opportunity to get the settings aligned.

lao shi
SA, 1313 posts
29 Sep 2012 2:55PM
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Stop Run Speed and Stop Run Angle - these options control how RealSpeed determines a run. This is used with the One Result per Run setting in the Divisions Options. To determine the end of a run, set the threshold stop run speed that you consider to be the end of a run.

If it was set to 20 then you could get two results for a single downwind run just by slowing below 20 knots. Set to zero you have to stop for the next run to be started.
So I think anything below planing speed should be ok.

Should not affect alpha (using the Alpha 500 for GT31 division in the GPSTC version of 1.928 (doppler)) because you turn through more than 90 degrees. Just tried 30 and 0 on my realspeed and it made no difference to alpha.

Just tried a Mile calc and if One result per run is ticked and I set the stop run speed at 30 then no miles are shown but by default one result per run is not ticked so that it can include gybes to get the distance.

The Stop run speed is also set by clicking Edit>delete slow points and altering the speed.

Froude
WA, 20 posts
29 Sep 2012 2:33PM
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Aren't we "brainiac" enough for you Paul!!

OK I'll go out on a limb....

Basically playing with the HDOP or Min Sats doesn't matter unless you have crap data or you make the criteria too stringent (ie you must have 500 satellites locked!).

For the stop speed and alpha issue, its probably because when you stop (jump off) your speed doesn't go to zero. It fluctuates because the satellites are moving, check your tracks and you'll see "stopped" speed varies up to and sometimes over 1 knot. This is then worse if you fall in on a gybe and you move the board around etc, then your "stopped" speed could be over 2 knots! So if your stop speed is set too low, as your actual speed fluctuates above and below your set "stop speed", realspeed may think your alpha has stopped and started 10 or 20 times while you get back on the board. Mal may be the only definitive answer for this one, but a stopped speed somewhere from 7 down to 2 knots seems to give the same result. It also matches KA72. Also if your top 5 gybes never drop below or equal your stop run speed (also assuming you also have a very low stop run speed ie < 2kts), you will never see this problem in your tracks (if only )

So although DHOP and Min Sats shouldn't matter, I use

Time Threshold = 200 (default)
Speed Threshold = 50 (default unless you're damn fast!)
Acc Threshold = 7kt/s2 seems a reasonable default, though I doubt 5kt/s2 would have too much affect. How fast are the start of your catapults?? If you set it too low the accelerations in gusts will be marked as invalid.
Stop Run Speed = 7 (However any value down to 2 knots should work)
Doppler Error = (Not sure but I've never seen it go above 0 for my GT31)
DHOP = 4 (default - reasonable upper limit, could even be lower)
Min SATS = 5 (reasonable minimum, usually we get 8+ in Perth)
Decc Threshold = Similiar to Acc, 15 seems reasonable and would 10 really make a difference? 10 is similar to jumping off your board at 10 knots, so anything above that you definitely don't need for your results.
Stop Angle = 90 (default for a change of direction)

Paul if you are having problems with a higher Stop Run Speed, send me the track and I'll have a look.

Paul Kelf
WA, 678 posts
29 Sep 2012 8:33PM
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Thanks guys, I pretty much understand it now but was concerned that everyone using different settings may be getting different results.
The Alphas I was checking were clearly where someone had stalled mid gybe or fallen in.
KA72 was giving a reasonable Alpha.
Realspeed was showing it more clearly as you get a visual.
I think because my Realspeed "stop run" was set to .85 it was finishing the run where they stalled or stopped & started another run.
Maybe I should run the tracks again with a higher setting & compare.

Froude
WA, 20 posts
29 Sep 2012 9:23PM
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Out of interest some google research showed GPS-Speedsurfing has:

www.gps-speedsurfing.com/default.aspx?mnu=item&item=BasicRules

"For Doppler devices in the GPS analysis software the following settings are necessary:

max. Accel. [5 m/s?]
max. HDoP (5)
min. Sats (5)"

5m/s2 = 9.72 knots/s (edit - just noticed my previous post should be knots/s not kt/s2)

Then in the records section it specifies your GT11/31 min speed should be set to 0/OFF for 1 or 24 hour records (In data logger and memory card) for speed and distance.

Wonder what invalid filters KA72 uses? Not that its likely to matter too much, but when it comes to bragging rights it would be nice to know!!



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"Realspeed Settings" started by Paul Kelf