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post #16 of (permalink) Old 03-12-2014, 01:35 PM
High on the Mountain Top
 
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Quote:
quote:Originally posted by oplopanax

People think the devices are more accurate than they are. 99% of the GPS units I've used report the 50% confidence interval, which is misleading. This project lets you compare the precision across devices, and under different environmental conditions.

For instance, the people flying UAVs keep claiming that they are accurate to within a metre, which is clearly not true, and you can see it for yourself.

Any conclusions you make based on this study would only be applicable to consumer grade units. Though I suppose that is the purpose.
Using a base station and a dual frequency GPS receiver absolute accuracies of 0.5 metre at 95% confidence level are regularly achieved on UAV projects. This thing http://www.aibotix.com/id-3d-laser-scanner.html for example, doesn't rely on a $400 Garmin unit for positional data. Accuracies of several mm are acheivable with stationary survey grade units. We've done GPS surveys accurate enough to measure ground subsidence of several cm and the effect of plate tectonics on the positions of survey hubs over the course of a few years.

Edit - for hiking or finding a road spur, trailhead etc. I've never cared if my GPS was out by 15 metres as it doesn't need to be any better than that to know where I am.
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post #17 of (permalink) Old 03-12-2014, 02:45 PM
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The practical application is still escaping me. UAV???some kind of climbing drone that will preclip the bolts on a hard route for you????



Quote:
quote:Originally posted by oplopanax

People think the devices are more accurate than they are. 99% of the GPS units I've used report the 50% confidence interval, which is misleading. This project lets you compare the precision across devices, and under different environmental conditions.

For instance, the people flying UAVs keep claiming that they are accurate to within a metre, which is clearly not true, and you can see it for yourself.

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post #18 of (permalink) Old 03-12-2014, 02:54 PM
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The question remains why anyone needs surveyor-grade accuracy in a recreational unit.
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post #19 of (permalink) Old 03-12-2014, 03:22 PM
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I think this would be more significant in environmental, mineral exploration or other types of projects where the relative positions of closely-spaced (E.g., <15 m) samples might be important. As far as recreational hiking is concerned, if the multiple possibilites of your GPS location are all within speaking distance then you might as well consider them to all be in the same place - a 10 m error is of no consequence.
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post #20 of (permalink) Old 03-12-2014, 03:45 PM Thread Starter
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Quote:
quote:Originally posted by magnetite

Quote:
quote:Originally posted by oplopanax

People think the devices are more accurate than they are. 99% of the GPS units I've used report the 50% confidence interval, which is misleading. This project lets you compare the precision across devices, and under different environmental conditions.

For instance, the people flying UAVs keep claiming that they are accurate to within a metre, which is clearly not true, and you can see it for yourself.

Any conclusions you make based on this study would only be applicable to consumer grade units. Though I suppose that is the purpose.
Using a base station and a dual frequency GPS receiver absolute accuracies of 0.5 metre at 95% confidence level are regularly achieved on UAV projects. This thing http://www.aibotix.com/id-3d-laser-scanner.html for example, doesn't rely on a $400 Garmin unit for positional data. Accuracies of several mm are acheivable with stationary survey grade units. We've done GPS surveys accurate enough to measure ground subsidence of several cm and the effect of plate tectonics on the positions of survey hubs over the course of a few years.

Edit - for hiking or finding a road spur, trailhead etc. I've never cared if my GPS was out by 15 metres as it doesn't need to be any better than that to know where I am.
Most UAV people are making claims based on consumer grade hardware.
Any survey grade GPS is going to be much more accurate.
It would be fun to see the error plot from such a device if you would have the time to upload it. You could also check the claims made by the manufacturer.
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post #21 of (permalink) Old 03-13-2014, 02:21 AM
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It seems that Paul is right, this is just about playing with your tool [:I] Whatever floats your boat.

When you get that UAV set up to pre-clip bolts send one Downunder, I could use one that can fit bolt plates onto carrots.
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