precise land copter on a truck with marvelmind?

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renxf
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Joined: Wed Oct 24, 2018 9:07 am

precise land copter on a truck with marvelmind?

Post by renxf »

Hi,
i want to precise land my copter on a moving car.
could i using the marvelmind navigation system for this?
i put four station beacon at the corner of the car. the copter fly on the top of car with a mobile beacon.
i need the relative position information of the copter and the car.
could someone confirm if the marvelmind navigation system working in the moving situation?
and what is the minimal distance between the station beacon?

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admin
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Re: precise land copter on a truck with marvelmind?

Post by admin »

Hello,

Yes, it would work, if the base between beacons is large enough - a few meters, hopefully.
XY would be good. Z would be good in the far field, but wouldn't be good during landing. For that, we recommend using vertical maps: 4 stationary beacons on the roof and 2 beacons 1-2 meters above the beacon on the roof: https://www.youtube.com/watch?v=_swkCCcMq5A - example of tracking using vertical submaps. Check the smaller screens of the Dashboard to analyze the beacons configuration (green dots).

Stationary beacons may be as close as 50 cm, if you wish, but the precision would suffer greatly, because of basic geometry.
Very rough rule of thumb: if you want +-2cm precision on 5m, then you need 5m base. Very rough, but there is a point. If you have 1m base, on 10m, you may have roughly 10x2 => +-20cm precision. Something like this.

Another element to pay attention to is the noise from the copter. If the distance between beacons is small, it will be pretty difficult to set the manual gain so that the noise from the copter isn't too strong.

So, recommendation is pretty basic:
- Use as large base as possible
- Use Vertical Submaps for precise Z. If not possible, take only X,Y from Indoor "GPS" when flying near the roof and use another Z data for landing - 1D lidar, optical flow, etc. In the farther field - at least, 1-2m height - all X,Y,Z from Indoor "GPS" would be precise. The precision degradation will start kick in, when you have too large distance compare to you base >5-10 times or so.

BR,
Maxim

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