Lighthouse Crossing Beam Locally

Topics related to the Lighthouse positioning system, configuration and use
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emwang
Beginner
Posts: 2
Joined: Tue Dec 07, 2021 7:59 pm

Lighthouse Crossing Beam Locally

Post by emwang »

Hello! I've been working on replicating your lighthouse positioning crossing beam algorithm locally with lh2.

Here are the steps I've taken so far:
- Log the lighthouse.angle0x_0lh2 etc variables and the lighthouse.x,y,z variables
- Calculate the intersection vectors directly using the lighthouse.angle0x_0lh2 angles
- Rotate by the rotation matrices from lighthouse memory and translate by the origin positions from lighthouse memory
- Find the intersection point following my python version of https://github.com/bitcraze/crazyflie-f ... c#L63-L102

Here's my result:
Screen Shot 2022-02-23 at 3.29.30 PM.png
Screen Shot 2022-02-23 at 3.29.30 PM.png (75.16 KiB) Viewed 8260 times
Where the orange line is made from lighthouse.x,y,z and the blue is my calculated positions.

My questions:
- The positions don't match up, so I was wondering if there is an intermediate processing step that I missed?
- What is the error for your crossing beams method and for the sweep angle method?
- Is yaw pitch roll from the lighthouse or somewhere else like the imu?
- Could you point me towards documentation about the sweep angle method? I would like to try to recreate it as well.

Thanks for all your help!
kristoffer
Bitcraze
Posts: 630
Joined: Tue Jun 30, 2015 7:47 am

Re: Lighthouse Crossing Beam Locally

Post by kristoffer »

lighthouse.angle0x_0lh2 contains the lighthouse V2 angles, that is for a tilted light plane. The crossing beam code you are pointing at assumes lighthouse V1 angles, that is two perpendicular sweeps.
You can find information about the system here https://www.bitcraze.io/documentation/r ... ighthouse/
An more specifically how to go from V2 to V1 angles here https://www.bitcraze.io/documentation/r ... onversion/
What is the error for your crossing beams method and for the sweep angle method?
They should be about the same.
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