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Can't get precise z Data.

Posted: Fri Jul 24, 2020 6:44 am
by mustafa_soliman

I wanted to make a 3D map in 20m x 20m x 4 m area.
I am using HW4.9 for stationary beacons and HW4.9 with IMU for the mobile beacon on tripod.
4 beacons at heights of 50 cm from the ground facing each other and the other 2 are on height of 4 meter from ground
NIA configuration.
I enter coordinates manually
I used 3 configurations
4 beacons in 2D mode
4 beacons in 3D navigation mode
and 6 beacons (as stated in the manual).
No. of periods 5
The stationary beacons always are checked for communication with mobile beacon by an oscilloscope.

I am using ROS to collect the data for analysis.
And I have some results

I could get 10 cm accuracy in the xy direction in all position in that area.
but z direction is not accurate at all and I have some questions.

1- when I call the raw data from ROS in 3D maps, it just give the data of submap 1, the vertical map only.
can we call the raw distance for all beacons ?
2- In x,y level. The accuracy decrease when the mobile beacon approach the horizontal level map of the beacon.
Except in 2D mode 4 beacons.
3- In the vertical level the accuracy is high only when you approach the vertical plan of the beacons, when you go away from it it decrease.
4- the data is stoped in 3D maps when we approach the horizontal. exactly after the mobile beacon make vertex angle of pyramid more than 160 degrees.

Any Explanation for the position error? I hope there is debugging tools like saving the mobile beacon - stationary beacon distances
via Dashboard or ROS.

Re: Can't get precise z Data.

Posted: Fri Jul 24, 2020 4:48 pm
by Alexander_Marvelmind

Writing you about the Z precision:

- Fist of all, please check our Operating Manual - ... manual.pdf - 9.9 System Accuracy Evaluation chapter

- We have a special installation for Stable Z. Please check details about Vertical Z in the Placement Manual - ... manual.pdf - Stable “Z” for drone – settings and recommendations chapter

- We also have a tutorial video about drones on our YouTube channel -

Re: Can't get precise z Data.

Posted: Tue Aug 18, 2020 12:31 pm
How can you get a stable Z if you only have beacons on the floor?

Re: Can't get precise z Data.

Posted: Tue Dec 15, 2020 6:36 pm
by smoker77

In the 'Stable “Z” for drone' chapter there are two submaps - beacons of the 'submap 2' are on the floor and used for X,Y location.
Beacons of the 'submap 1' reuse two beacons from the floor and use also two beacons on the wall, this submap is used for precize Z, even when drone is near floor.