Boat racing or GPS speed watching
07-06-2004 | 10:35 PM
#1
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From: MIDDLETOWN,DE
Boat racing or GPS speed watching
Guys what has boat racing become,for some of us it is still put a boat together and run it in the class that there are other equally prepared boats and run the entire race flat out and see who can win and for others it has become a race of who can stay under the GPS speeds and win,what is you guys opinion of the way it should be,run flat out and hope you are better than the other guy or put yourself in a class and run just hard enough to win but not have to lean on your equipment or breakout of your projected speed / better known as sand bagging it to get a checkered flag,just curious on what your opinions are.
07-07-2004 | 05:28 AM
#2
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From: Quogue, NY
Re: Boat racing or GPS speed watching
Racing is about how fast one can get around the racecourse. That is a principle easily understood by fans, sponsors and racers alike. When the #5 finisher gets the trophy, because “the other guys went faster than him,” then we have a problem
Apart from this conceptual problem, there is a huge technical problem with using the GPS to measure breakout. In its current form, the GPS simply is not suited for that task.
I had done some research into the GPS matter before, even spoke with one of the scientists who developed GPS. He, by the way, shuddered when he heard that "his" system is used to measure max speed.
This is what I found out:
1.) The GPS system can be amazingly precise. The actual precision is a function of the hardware and especially of the software being used. Speed readings after the decimal point should be taken with a big lump of salt. I have three independent GPS systems on board, none of them cheap, and they never agree.
2.) GPS speed readings are prone to "blips" or "spikes." This is due to various factors, but the biggest influencer is the antenna being momentarily obscured. Locking up a handheld in a pelican case and throwing this in the boat is an invitation do disaster.
3.) These “blips” or “spikes” are also registered during what is called a “PDOP (positional dilution of precision) spike.” This phenomenon is well documented ( for instance http://www.schriever.af.mil/GpsSuppo...3DOP_Spike.htm ) but not completely understood. If that phenomenon happens during a race, there will be lots of DQs.
3.) In regular use, these blips are usually not noticed. The tattle-tale function though works like a sample-and-hold circuit that records the highest reading. If a spike occurs, the highest reading reflects the spike. It is a false reading.
4.) If speed readings would be examined over time, these blips would be easily identified.
Some things I would do:
Immediate: Strap Pelican case to solid object on the boat with antenna having an unobstructed path to the sky.
Midterm:
Either: Talk a GPS manufacturer into making special "race" units with a more aggressive dampening factor for the max speed reading. When setting up boats, we like to see the reading solid for at least 15 seconds. The race unit would take a sample average over a 15 to 30 sec window. That would eliminate most blips.
Or: Construct your own race unit. It's an active GPS antenna (the hockey puck style) mounted to the outside of a pelican case. In the pelican is a small data recorder that CONTINUOSLY records the NMEA output of the GPS. Now you have readings over time, and you can throw out all blips, even the PDOP spike phenomenon.
Or: Move to a spec class. And suddenly, it’s back to how fast you can get around the racecourse again.
Apart from this conceptual problem, there is a huge technical problem with using the GPS to measure breakout. In its current form, the GPS simply is not suited for that task.
I had done some research into the GPS matter before, even spoke with one of the scientists who developed GPS. He, by the way, shuddered when he heard that "his" system is used to measure max speed.
This is what I found out:
1.) The GPS system can be amazingly precise. The actual precision is a function of the hardware and especially of the software being used. Speed readings after the decimal point should be taken with a big lump of salt. I have three independent GPS systems on board, none of them cheap, and they never agree.
2.) GPS speed readings are prone to "blips" or "spikes." This is due to various factors, but the biggest influencer is the antenna being momentarily obscured. Locking up a handheld in a pelican case and throwing this in the boat is an invitation do disaster.
3.) These “blips” or “spikes” are also registered during what is called a “PDOP (positional dilution of precision) spike.” This phenomenon is well documented ( for instance http://www.schriever.af.mil/GpsSuppo...3DOP_Spike.htm ) but not completely understood. If that phenomenon happens during a race, there will be lots of DQs.
3.) In regular use, these blips are usually not noticed. The tattle-tale function though works like a sample-and-hold circuit that records the highest reading. If a spike occurs, the highest reading reflects the spike. It is a false reading.
4.) If speed readings would be examined over time, these blips would be easily identified.
Some things I would do:
Immediate: Strap Pelican case to solid object on the boat with antenna having an unobstructed path to the sky.
Midterm:
Either: Talk a GPS manufacturer into making special "race" units with a more aggressive dampening factor for the max speed reading. When setting up boats, we like to see the reading solid for at least 15 seconds. The race unit would take a sample average over a 15 to 30 sec window. That would eliminate most blips.
Or: Construct your own race unit. It's an active GPS antenna (the hockey puck style) mounted to the outside of a pelican case. In the pelican is a small data recorder that CONTINUOSLY records the NMEA output of the GPS. Now you have readings over time, and you can throw out all blips, even the PDOP spike phenomenon.
Or: Move to a spec class. And suddenly, it’s back to how fast you can get around the racecourse again.
Last edited by Peconic; 07-07-2004 at 06:51 AM.
07-07-2004 | 07:35 AM
#5
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From: MIDDLETOWN,DE
Re: Boat racing or GPS speed watching
Q Ball.
The Progression that you guys run is a sweet ride,so dont take what I am saying wrong but in reality it is a F1 boat and a good one at that.
The Progression that you guys run is a sweet ride,so dont take what I am saying wrong but in reality it is a F1 boat and a good one at that.
07-07-2004 | 08:20 AM
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From: Enola, Pa
Re: Boat racing or GPS speed watching
We have raced for years with the gps and have yet to get a bad blip, not that it does not happen, as stated before if you set up for your class you do run WOT and it tightens up the competition. Is this any different then adding weight or taking out rpm out of spec classes to increase competition? I have watched for years the p classes and have seen the over zealous and the "sand bagger" so I think we need some one to regulate it somehow and even though gps watching may not be the best, it is a start for tighter finishes. ie some of the sarasota classes had three finishers within 30 seconds. That is better racing then boat finishing minutes apart. Other than that run spec classes.
07-07-2004 | 08:25 AM
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Posts: 5,650
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From: Lake Murray, SC
Re: Boat racing or GPS speed watching
Originally Posted by Peconic
Racing is about how fast one can get around the racecourse. That is a principle easily understood by fans, sponsors and racers alike. When the #5 finisher gets the trophy, because “the other guys went faster than him,” then we have a problem
Apart from this conceptual problem, there is a huge technical problem with using the GPS to measure breakout. In its current form, the GPS simply is not suited for that task.
I had done some research into the GPS matter before, even spoke with one of the scientists who developed GPS. He, by the way, shuddered when he heard that "his" system is used to measure max speed.
This is what I found out:
1.) The GPS system can be amazingly precise. The actual precision is a function of the hardware and especially of the software being used. Speed readings after the decimal point should be taken with a big lump of salt. I have three independent GPS systems on board, none of them cheap, and they never agree.
2.) GPS speed readings are prone to "blips" or "spikes." This is due to various factors, but the biggest influencer is the antenna being momentarily obscured. Locking up a handheld in a pelican case and throwing this in the boat is an invitation do disaster.
3.) These “blips” or “spikes” are also registered during what is called a “PDOP (positional dilution of precision) spike.” This phenomenon is well documented ( for instance http://www.schriever.af.mil/GpsSuppo...3DOP_Spike.htm ) but not completely understood. If that phenomenon happens during a race, there will be lots of DQs.
3.) In regular use, these blips are usually not noticed. The tattle-tale function though works like a sample-and-hold circuit that records the highest reading. If a spike occurs, the highest reading reflects the spike. It is a false reading.
4.) If speed readings would be examined over time, these blips would be easily identified.
Some things I would do:
Immediate: Strap Pelican case to solid object on the boat with antenna having an unobstructed path to the sky.
Midterm:
Either: Talk a GPS manufacturer into making special "race" units with a more aggressive dampening factor for the max speed reading. When setting up boats, we like to see the reading solid for at least 15 seconds. The race unit would take a sample average over a 15 to 30 sec window. That would eliminate most blips.
Or: Construct your own race unit. It's an active GPS antenna (the hockey puck style) mounted to the outside of a pelican case. In the pelican is a small data recorder that CONTINUOSLY records the NMEA output of the GPS. Now you have readings over time, and you can throw out all blips, even the PDOP spike phenomenon.
Or: Move to a spec class. And suddenly, it’s back to how fast you can get around the racecourse again.
Apart from this conceptual problem, there is a huge technical problem with using the GPS to measure breakout. In its current form, the GPS simply is not suited for that task.
I had done some research into the GPS matter before, even spoke with one of the scientists who developed GPS. He, by the way, shuddered when he heard that "his" system is used to measure max speed.
This is what I found out:
1.) The GPS system can be amazingly precise. The actual precision is a function of the hardware and especially of the software being used. Speed readings after the decimal point should be taken with a big lump of salt. I have three independent GPS systems on board, none of them cheap, and they never agree.
2.) GPS speed readings are prone to "blips" or "spikes." This is due to various factors, but the biggest influencer is the antenna being momentarily obscured. Locking up a handheld in a pelican case and throwing this in the boat is an invitation do disaster.
3.) These “blips” or “spikes” are also registered during what is called a “PDOP (positional dilution of precision) spike.” This phenomenon is well documented ( for instance http://www.schriever.af.mil/GpsSuppo...3DOP_Spike.htm ) but not completely understood. If that phenomenon happens during a race, there will be lots of DQs.
3.) In regular use, these blips are usually not noticed. The tattle-tale function though works like a sample-and-hold circuit that records the highest reading. If a spike occurs, the highest reading reflects the spike. It is a false reading.
4.) If speed readings would be examined over time, these blips would be easily identified.
Some things I would do:
Immediate: Strap Pelican case to solid object on the boat with antenna having an unobstructed path to the sky.
Midterm:
Either: Talk a GPS manufacturer into making special "race" units with a more aggressive dampening factor for the max speed reading. When setting up boats, we like to see the reading solid for at least 15 seconds. The race unit would take a sample average over a 15 to 30 sec window. That would eliminate most blips.
Or: Construct your own race unit. It's an active GPS antenna (the hockey puck style) mounted to the outside of a pelican case. In the pelican is a small data recorder that CONTINUOSLY records the NMEA output of the GPS. Now you have readings over time, and you can throw out all blips, even the PDOP spike phenomenon.
Or: Move to a spec class. And suddenly, it’s back to how fast you can get around the racecourse again.
Seriously though, it makes sense.
07-07-2004 | 09:04 AM
#8
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Posts: 5,136
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From: Edison NJ USA
Re: Boat racing or GPS speed watching
Untill someone comes up with a better mouse trap its better than nothing. What happened to if you broke out you moved up a class?
I still say just have a cannon ball run with 2 starts and no classes. Race for the fun and no winners.
MD
I still say just have a cannon ball run with 2 starts and no classes. Race for the fun and no winners.
MD
07-07-2004 | 09:05 AM
#9
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Posts: 2,292
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From: Grand River, Ohio
Re: Boat racing or GPS speed watching
We all know the purpose of the GPS system in P-class racing. The idea for P-class was to be able to bring boats back into racing that were either not able to run in a spec class or no longer competitive in a spec class due to rules and or technology changes. I have been invovled in Local or "P" class racing since 1997 when we started promoting it in the GLSCS.
In the GLSCS rules it is stated that it is the discression of the Chief Inspector and Referee to allow a boat to compete in a particular "P" class based on the boats maximum speed in optimum conditions. The GPS is small part of the puzzle. Another check. I agree that the GPS is not the be all end all. But racing is racing and racers will be racers, I am one also. we need to keep the guys on their toes.
Andrew D. Bloom
GLSCS Chairman
In the GLSCS rules it is stated that it is the discression of the Chief Inspector and Referee to allow a boat to compete in a particular "P" class based on the boats maximum speed in optimum conditions. The GPS is small part of the puzzle. Another check. I agree that the GPS is not the be all end all. But racing is racing and racers will be racers, I am one also. we need to keep the guys on their toes.
Andrew D. Bloom
GLSCS Chairman
