GPS accuracy is the Holy Grail

SPP · Nov 5, 2016

Mauiwind said:
Give me me a camera platform that will allow me to program a shot with reliable, drop dead accurate, repeatable motion control. Yeah, lets make it tricky, lets autonamously fly through holes the size of tires, lets program in easing in and out of waypoints and camera movements. Lets use the inherent flexibility of the UAVs to go whete no crane or steadicam has gone before.
Can't do it. Crap, call in the cranes, burly grips and ground based motion control bots.

LOL... no GP assist can do what u ask for. RTK or not, what you need is something permanent on rail and can
be used withour radio/gps signal aka hard wired connection.

Mauiwind · Nov 6, 2016

SPP said:
LOL... no GP assist can do what u ask for. RTK or not, what you need is something permanent on rail and can
be used withour radio/gps signal aka hard wired connection.

Welly welly well... Whose right? Another fellow says that RTK GPS will give a UAV centimeter (or was it millemeter?) resolution in 3D space.
My investigation though as in depth as my non doctorate mind can gather, is that its not only complex to make happen, but that some of these ideas for UAVs are yet to be actualized. In any event, its not like set it and forget it.
Who can tell us what we might expect with the implementation of this technology? How useful can it be for mapping missions with nano accuracy? How much will it cost? Is it, will it, be portable?
Is RTK just an idea, or has someone actually flown a UAV and demonstrated the talked about accuracy of such flight?

pyrate · Nov 6, 2016

the RTK unit that is coming from the makers of Pixhawk 2.1 will run about 600 bucks
Have not seen videos yet, but as I understand it, arducopter 3.4 will support it.
So technically if they ever rebase solo, (underway) then you could possibly retrofit solo for it.
Still some unknowns
I am running Jordi's M8 and not really sure I need more accuracy

Hansolo808 · Nov 6, 2016

Hansolo808 · Nov 6, 2016

Mike Boland · Nov 6, 2016

Mauiwind said:
Welly welly well... Whose right? Another fellow says that RTK GPS will give a UAV centimeter (or was it millemeter?) resolution in 3D space.
My investigation though as in depth as my non doctorate mind can gather, is that its not only complex to make happen, but that some of these ideas for UAVs are yet to be actualized. In any event, its not like set it and forget it.
Who can tell us what we might expect with the implementation of this technology? How useful can it be for mapping missions with nano accuracy? How much will it cost? Is it, will it, be portable?
Is RTK just an idea, or has someone actually flown a UAV and demonstrated the talked about accuracy of such flight?

As I said previously we are getting +/-6mm variance from RTK.
And it will be set and forget, although the accuracy depends on 2 main factors.
1. Multi frequency GNSS. A single frequency consumer 'GPS' system cannot give you real accuracy.
2. An accurate base station over a known accurate survey point. Without this reference you are just pissing into the wind.

As you see above, Emlid have released a product, and the next Ublox release has RTK apparently.

For the accuracy we are after the cost of the RTK gear is generally out of reach of all but the profession.
As a guide, the on board RTK GNSS receiver is $12K, and the base station is at least $25K.
But then, this gives us the accuracy people will pay for, e.g.: stock pile measurements +/- 0.03%

Sharpman · Nov 6, 2016

Mauiwind,
You have the right idea. Coming from the professional aerial cinema world, I totally agree with you that having absolutely accurate and repeatable moves with a drone will be huge for the industry, and I'm working on a solution. The RTK tech is one possibilty and is almost there. But the user interfaces to plan and edit the flight paths in a way that works in the fast paced film production environment is going to take a fair bit more work. Stay tuned....

SPP · Nov 6, 2016

Guys,

Centimeters accuracy GPS wise is possible with RTK yes. Let say that 6mm accuracy as described. But do remember that a drone is a flying platform meaning a "floating" system suspended by air pressure. Also being a floating platform, it is not only accuracy of position of 6mm as a problem, but the aiming of the camera to Hollywood accuracy which actually relies on a compass is another set of small problem, problem nevertheless.

If we are using a cinema mechanical-hydraulic crane, which we know is locked to the ground, expecting movement accuracy to say 3mm is do-able. 3mm movement accuracy is not an issue for mechanical device. Directional accuracy on mechanical-hydraulic device is repeatable and can be guaranteed, its about gear ratio or cubic millimeters of hydraulic fluid pumped to do the work. Any car factory welding robot can do 3mm accuracy easy...but hover that welding robot assuming we can make it a 1kg mini size...hover in air using big enough drone...that is another story.

Do consider that GPS with RTK correction positioning data is only as good as how the drone can place itself at those given positions.
The weak link is the drone.

.

ChrisM101 · Nov 7, 2016

Ok so we're talking GPS which is currently at 0.8 meters for civilians according to Airforce documents, on to centimeters, or millimeters.

Like it has been said the drone being able to hold that position is the challenge even if it can identify the location in a highly accurate manner. Can it hold it against the wind?

So id safely say 6 millimeter accuracy is un-needed even if possible, but also centimeter accuracy seems like a bit over kill.

What if anything would require greater than 1ft /0.3m accuracy? Survey is all i can think of?

How do you measure this in function. shine a laser straight down from the gps module?

Hansolo808 · Nov 7, 2016

You guys are taking this to another level the only way you can get the accuracy you want is through the use of a triangulated laser guidance system that is terrestrial based - you need powerful algorithms that can calculate GPS, laser, and sonar systems. Don't forget redijndant IMUs and compass.
It can be done!! But you need a deep pocket

David Boulanger · Nov 7, 2016

Really people the m8n will work just fine.
Regards,
David R. Boulanger

Mauiwind · Nov 29, 2016

Hansolo808 said:
You guys are taking this to another level the only way you can get the accuracy you want is through the use of a triangulated laser guidance system that is terrestrial based - you need powerful algorithms that can calculate GPS, laser, and sonar systems. Don't forget redijndant IMUs and compass.
It can be done!! But you need a deep pocket

Sounds like a plan. Deep pockets?. . . And we ask ourselves, "who would possibly benefit from such capabilities? Ah, you guessed it, the US DOD. If a contractor hasn't already done it, (and developed an application for such capabilities) I'd be very disappointed. It doesnt take Gene Roddenbery to imagine some very amazing (and perhaps quite deadly) applications for the aforementioned enhanced drone. Good news though... it means that at some place and time, it'll be available to us.

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Mauiwind · Nov 29, 2016

SPP said:
Guys,

Centimeters accuracy GPS wise is possible with RTK yes. Let say that 6mm accuracy as described. But do remember that a drone is a flying platform meaning a "floating" system suspended by air pressure. Also being a floating platform, it is not only accuracy of position of 6mm as a problem, but the aiming of the camera to Hollywood accuracy which actually relies on a compass is another set of small problem, problem nevertheless.

If we are using a cinema mechanical-hydraulic crane, which we know is locked to the ground, expecting movement accuracy to say 3mm is do-able. 3mm movement accuracy is not an issue for mechanical device. Directional accuracy on mechanical-hydraulic device is repeatable and can be guaranteed, its about gear ratio or cubic millimeters of hydraulic fluid pumped to do the work. Any car factory welding robot can do 3mm accuracy easy...but hover that welding robot assuming we can make it a 1kg mini size...hover in air using big enough drone...that is another story.

Do consider that GPS with RTK correction positioning data is only as good as how the drone can place itself at those given positions.
The weak link is the drone.

.

The weak link in your assesment is interesting. So then, the resolution of the flight control would need to be greater. Doable?

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Mauiwind · Nov 29, 2016

It has occurred to me that fixed position, triangulation lasers would be enough.
Btw, I just bought an mRO GPS thingie... stoked... ill let ya know how it goes....

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Mauiwind · Dec 23, 2016

M8n is a terrific device.. So far, up to 17 sats.. Signal. Strength not noted.. Ready to fly in 5-30 seconds from boot and launch position.

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