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The PiT

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Created by sailquik > 9 months ago, 24 Sep 2009
sausage

sausage

QLD, 4873 posts
29 Sep 2009 12:48PM
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AUS1111 said...

Great photos Jodi - I especially like the one of the guy just sitting looking forlorn and broken with his sand covered board.


Yeah, that's a great photo although I thought he was only sitting down so he didn't get blown away.

Speaking of being blown away, I am still amazed at Craig and Tony's (and others) speeds for Sunday - I guess it'll be a day long remembered for those who were there.

PS -Does anyone have video from the shore? - I keep reminding myself of the Chris L video sometime ago when he hit 50knots and another sailors rig flew through the air just after he passed.

drift

drift

VIC, 737 posts
29 Sep 2009 1:50PM
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Hi Sausage,
There is footage from the shore which i am cutting together for a doco.
We also had some board mounted cams on Spotty (see above) and a helmet cam on Kato.
I'll post some snippets on Seabreeze once I have something to show.
mick

Bonominator

Bonominator

VIC, 5477 posts
29 Sep 2009 2:42PM
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Nice Pics Jodi.

Wow Monday is like another planet compared to Sunday!

My head is still reeling from the experience. After dropping the trackpoints from the second (and fasted run by miles) I'm investing in 2 x GT31's or next model GPS. Can't have a situation where I hit 48knots doppler speed and then can't verify it with trackpoints!

mr love

mr love

VIC, 2401 posts
29 Sep 2009 4:10PM
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Oh Ado , I wondered why you hadn't posted. I hope you get it sorted mate, that would be pretty tragic.
I am so impressed how you were handling the conditions. I kept crashing just as I was accellerating past the dunes, both times at exactly the same speed, just over 39 knots and at the same place. The board feels really nervous with the 20 in it, totally different to when I run the bigger fin when it is just so easy and rock solid. Maybe I just need to run the mast track further forward, need more time in 35knots plus to get it tuned one thinks.
Well done, awesome effort to all. Bring on the next one!!!!

Bonominator

Bonominator

VIC, 5477 posts
29 Sep 2009 11:33PM
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mr love said...

Oh Ado , I wondered why you hadn't posted. I hope you get it sorted mate, that would be pretty tragic.
I am so impressed how you were handling the conditions. I kept crashing just as I was accellerating past the dunes, both times at exactly the same speed, just over 39 knots and at the same place. The board feels really nervous with the 20 in it, totally different to when I run the bigger fin when it is just so easy and rock solid. Maybe I just need to run the mast track further forward, need more time in 35knots plus to get it tuned one thinks.
Well done, awesome effort to all. Bring on the next one!!!!


Thanks mate. Yeh it's a bit tragic but still managed a verifiable 45 peak. Just can't verify the data and tracks are all over the place for the two minutes of that run. It definitely was the fastest towards the end. I sailed way down to the long dune at the end, fully overpowered and fully sheeted in. No sign of fatigue yet at that point either as I'd only had one half walk back up. No one sailed the run for a couple of minutes afterwards as a massive 50knot blast came through so I can't compare satellites with others. I had trouble turning the sail around!

I run the KA 20 too but put the mast track centre about 8cm from the back rather than all the way back - even with the 4.4m to keep the nose down and run long harness lines (27" ish) with a moderately high boom to keep the rig vertical. Any sudden gust is translated to drive rather than board lift. That's my theory anyway and I'm sticking to it. Bring it on again!

sailquik

sailquik

VIC, 6165 posts
30 Sep 2009 11:24AM
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sailquik

sailquik

VIC, 6165 posts
30 Sep 2009 11:51AM
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We had a fantastic day at the Go Cart track yesterday. The results are still being argued over but it was obvious eveyone had a great time.

Being speed freaks, many of us wore our GPS in the Cart. We had the idea that we could replay our races afterwards in GPSAR but we haven't quite got there yet.
Anyhow, I had my Proto GT-35 so it was interesting to compare the data from the 5hz chip with the 1hz chip. Below is a picture of the tracks in 5hz:



Here is one corner zoomed in at 5 hz:



And here is the same corner at 1hz



Quite a difference ay!

elmo

elmo

WA, 8868 posts
30 Sep 2009 10:17AM
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What was your Alpha then?

sailquik

sailquik

VIC, 6165 posts
30 Sep 2009 12:44PM
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elmo said...

What was your Alpha then?


26.074!



elmo

elmo

WA, 8868 posts
30 Sep 2009 10:47AM
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I can only dream of a 25 Alpha Go-kart or not

Looked like a fun day

Roo

Roo

876 posts
30 Sep 2009 10:50AM
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Wait until you see the data at 10 hz, smooth as a baby's bum!

sailquik

sailquik

VIC, 6165 posts
30 Sep 2009 12:53PM
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Roo said...

Wait until you see the data at 10 hz, smooth as a baby's bum!


Yeah, both Cris and I has 10 hz loggers in the car and completrely forgot about them until after the session. Next time (and it will be soon! ) I will carry that as well.

Roo

Roo

876 posts
30 Sep 2009 10:57AM
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sailquik said...

Roo said...

Wait until you see the data at 10 hz, smooth as a baby's bum!


Yeah, both Cris and I has 10 hz loggers in the car and completrely forgot about them until after the session. Next time (and it will be soon! ) I will carry that as well.


It's one thing to have them in the car, it's a whole other world to have them download 10 hz 3d speed data! [}:)]

yoyo

yoyo

WA, 1646 posts
30 Sep 2009 12:27PM
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Andrew, what brand 10Hz logger do you have?

mineral1

mineral1

WA, 4564 posts
30 Sep 2009 12:32PM
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sailquik, this Proto GT-35, is that a legit model coming onto the market, or an enhanced model you guys have tweaked over there?
My GT-11 due for upgrade some time in near future, and was wondering if your proto iwill be the replacement for the current GT-31?

regards
mineral

windjunky

windjunky

VIC, 401 posts
30 Sep 2009 10:48PM
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My version of the Prom wind graph for Spotties big day - 48.5 knot average wind over the day; incredible (that you guys could even stand up)!


sailquik

sailquik

VIC, 6165 posts
1 Oct 2009 12:40AM
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Roo said...

sailquik said...

Roo said...

Wait until you see the data at 10 hz, smooth as a baby's bum!


Yeah, both Cris and I has 10 hz loggers in the car and completrely forgot about them until after the session. Next time (and it will be soon! ) I will carry that as well.


It's one thing to have them in the car, it's a whole other world to have them download 10 hz 3d speed data! [}:)]



Huh? What do you mean by that Roo? I have used and downloaded the 10 hz data in the past. ????

sailquik

sailquik

VIC, 6165 posts
1 Oct 2009 12:47AM
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mineral1 said...

sailquik, this Proto GT-35, is that a legit model coming onto the market, or an enhanced model you guys have tweaked over there?
My GT-11 due for upgrade some time in near future, and was wondering if your proto iwill be the replacement for the current GT-31?

regards
mineral



Nope. This will not be a production model. It was one of a very small run of custom units that Tom Chalko had made with an extra MTK 5 hz GPS chip added to them alongside the Sirf3 chip. Locosys decided that there was no market to justify the production so they canned it.
The GT-31 will be current for at least another year, probably more. I have heard rumors of a Sirf4 chip but I understand it is at least a year or two off. Go for a GT-31 (or two).

Roo

Roo

876 posts
1 Oct 2009 4:17AM
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sailquik said...

Roo said...

sailquik said...

Roo said...

Wait until you see the data at 10 hz, smooth as a baby's bum!


Yeah, both Cris and I has 10 hz loggers in the car and completrely forgot about them until after the session. Next time (and it will be soon! ) I will carry that as well.


It's one thing to have them in the car, it's a whole other world to have them download 10 hz 3d speed data! [}:)]



Huh? What do you mean by that Roo? I have used and downloaded the 10 hz data in the past. ????


Looking at your 5 hz speed data from your go kart excursion it looks like a nmea.txt file that produced the data.



One of the reasons I pioneered the binary data with the GT-11 was the higher levels of precision and extra information available form the binary data. At 5 hz and 10 hz it's even more important to download the binary data as a lot of information is lost if it is recorded as nmea messages, the conversion to nmea also serves to slow down the on board processing and uses critical computing power and can lead to spikes.

Additionally all the 3d spatial and velocity measurements in their raw form are recorded to greater decimal levels of accuracy which produce much more accurate speed readings when post processed.

If you have logged all the data in binary code from your 10 hz gps unit then accept my apologies as I was mistaken in your level of expertise in this field. I can now log smooth, consistent binary data at 10 hz for full 3d speed precision and enhanced trackpoint accuracy. Aliasing problems have been avoided by using a sampling rate at two and a half times the navigation rate.

The next step is combining this with a 3d accelerometer to further improve the accuracy levels and adding real time embedded video for visual proof.

Roo

Roo

876 posts
1 Oct 2009 5:41AM
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10 hz 3d speed test file

sailquik

sailquik

VIC, 6165 posts
1 Oct 2009 1:18PM
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Roo said...

sailquik said...

Roo said...

sailquik said...

Roo said...

Wait until you see the data at 10 hz, smooth as a baby's bum!


Yeah, both Cris and I has 10 hz loggers in the car and completrely forgot about them until after the session. Next time (and it will be soon! ) I will carry that as well.


It's one thing to have them in the car, it's a whole other world to have them download 10 hz 3d speed data! [}:)]



Huh? What do you mean by that Roo? I have used and downloaded the 10 hz data in the past. ????


Looking at your 5 hz speed data from your go kart excursion it looks like a nmea.txt file that produced the data.

One of the reasons I pioneered the binary data with the GT-11 was the higher levels of precision and extra information available form the binary data. At 5 hz and 10 hz it's even more important to download the binary data as a lot of information is lost if it is recorded as nmea messages, the conversion to nmea also serves to slow down the on board processing and uses critical computing power and can lead to spikes.

Additionally all the 3d spatial and velocity measurements in their raw form are recorded to greater decimal levels of accuracy which produce much more accurate speed readings when post processed.

If you have logged all the data in binary code from your 10 hz gps unit then accept my apologies as I was mistaken in your level of expertise in this field. I can now log smooth, consistent binary data at 10 hz for full 3d speed precision and enhanced trackpoint accuracy. Aliasing problems have been avoided by using a sampling rate at two and a half times the navigation rate.

The next step is combining this with a 3d accelerometer to further improve the accuracy levels and adding real time embedded video for visual proof.



OK, its hard to understand what you are getting at when you post in cryptic comments. You are correct, we are only getting NMEA data from the MTK chip in the current configuration. Binary data would be a huge improvement and would indeed produce a smoother track and speed graph.

BTW, I make no claims to any special technical expertise in the internal workings of GPS. I am just an interested observer and user. Clearly you are going deeper into it.

What chip/unit are you using for your 10 hz binary logging?
Are you going to share your research and findings for the wider benefit of speed sailing? What is your agenda?

Roo

Roo

876 posts
1 Oct 2009 11:46AM
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OK, its hard to understand what you are getting at when you post in cryptic comments. You are correct, we are only getting NMEA data from the MTK chip in the current configuration. Binary data would be a huge improvement and would indeed produce a smoother track and speed graph.

BTW, I make no claims to any special technical expertise in the internal workings of GPS. I am just an interested observer and user. Clearly you are going deeper into it.

What chip/unit are you using for your 10 hz binary logging?
Are you going to share your research and findings for the wider benefit of speed sailing? What is your agenda?


Nothing cryptic about the post, I remarked it was obvious you were using nmea data for your 5 hz recordings and they lacked a high degree of accuracy.

Actually I have been sharing my research and findings for the last 3 years and have no agenda other than creating the most accurate gps systems for speedsailing.

The chipset is by U-Blox and has been around for quite a number of years. Yann and Manfred adapted their programs to read the data over 2 years ago so what I am doing is nothing new and has not been kept secret.

5 hz binary data recording was easy, the hard bit was 10 hz binary which I recently managed to crack. Both Yann and Manfred have been kept abreast of the development work I carried out.

The 3d speed measurement was an offshoot of the development work and a way to overcome some of the latent errors handheld gps units produce when they convert raw 3d data to 2d Speed Over Ground (SOG doppler) speeds. GPS-Results allows you to use this binary data to produce 3d speed results and the error estimations have been available for years now.

sailquik

sailquik

VIC, 6165 posts
1 Oct 2009 5:33PM
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Roo said...

OK, its hard to understand what you are getting at when you post in cryptic comments. You are correct, we are only getting NMEA data from the MTK chip in the current configuration. Binary data would be a huge improvement and would indeed produce a smoother track and speed graph.

BTW, I make no claims to any special technical expertise in the internal workings of GPS. I am just an interested observer and user. Clearly you are going deeper into it.

What chip/unit are you using for your 10 hz binary logging?
Are you going to share your research and findings for the wider benefit of speed sailing? What is your agenda?


Nothing cryptic about the post, I remarked it was obvious you were using nmea data for your 5 hz recordings and they lacked a high degree of accuracy.

Actually I have been sharing my research and findings for the last 3 years and have no agenda other than creating the most accurate gps systems for speedsailing.

The chipset is by U-Blox and has been around for quite a number of years. Yann and Manfred adapted their programs to read the data over 2 years ago so what I am doing is nothing new and has not been kept secret.

5 hz binary data recording was easy, the hard bit was 10 hz binary which I recently managed to crack. Both Yann and Manfred have been kept abreast of the development work I carried out.

The 3d speed measurement was an offshoot of the development work and a way to overcome some of the latent errors handheld gps units produce when they convert raw 3d data to 2d Speed Over Ground (SOG doppler) speeds. GPS-Results allows you to use this binary data to produce 3d speed results and the error estimations have been available for years now.



Great! What is the name and model of the receiver you are using and how do I configure it to produce and record binary data?

bigbear

bigbear

QLD, 151 posts
1 Oct 2009 6:35PM
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Enough of the technical crap! I was enjoying this thread.

Roo

Roo

876 posts
2 Oct 2009 1:30AM
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bigbear said...

Enough of the technical crap! I was enjoying this thread.


Apologies bigbear for going all tech, will take the discussion off forum and continue it in private.

sausage

sausage

QLD, 4873 posts
2 Oct 2009 9:36AM
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Roo said...

bigbear said...

Enough of the technical crap! I was enjoying this thread.


Apologies bigbear for going all tech, will take the discussion off forum and continue it in private.



I thought this thread was about the Pit, but now it's turning into the pits (pun not intended for go-cart racing reference)

As this forum is technically about GPS, I've got no problems with technical discussions (even though way out of my intellectual capacity), it's only when arguments start getting a bit heated about who has more hertz and a bigger sirf1267534 chip, that it gets a bit tedious.


Old Salty

Old Salty

VIC, 1271 posts
2 Oct 2009 10:57AM
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Now to get this back on topic - what has happened to the wind Last weekend could not sail because I haven't got the balls(or the equipment ) for 58 kts. This weekend I need a jet ski to tow me to put me on the plane Gotta love this sport. IS this HARDIE"S curse???

yoyo

yoyo

WA, 1646 posts
2 Oct 2009 11:37AM
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Matt,

Is there a Speedweek web site like last year?

I notice you are running a blog on seabreeze (www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=55769) but will there be a ranking or overall result?

By the way Andrew and Roo, Locosys make a 10Hz gps module so they COULD update the Navi if we let them know that is what we want.

see

http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=41&products_id=361

oldie

oldie

VIC, 356 posts
2 Oct 2009 3:33PM
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windjunky said...

My version of the Prom wind graph for Spotties big day - 48.5 knot average wind over the day; incredible (that you guys could even stand up)!


That's my home page, many thanks.

Still reckon that you should put up Pound Creek.
The teabaggers don't outnumber us ALL the time...
And speed runs are possible.

rick77

rick77

VIC, 121 posts
2 Oct 2009 5:53PM
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Old Salty said...

Now to get this back on topic - what has happened to the wind Last weekend could not sail because I haven't got the balls(or the equipment ) for 58 kts. This weekend I need a jet ski to tow me to put me on the plane Gotta love this sport. IS this HARDIE"S curse???


Hi Old Salty,

you should have come out to that other inlet (invo) it was a "gentle" 35-40 knot gusts on my windmeter Sunday morning... I only lasted 90 min but it was fun while I had some energy....

tide was too high in the morning for super flat water, the bank was just getting exposed when I left....

Rick


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"The PiT" started by sailquik



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