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doc:lighthouse:setup [2019-10-09 16:46]
kristoffer
doc:lighthouse:setup [2019-11-29 15:29]
kristoffer
Line 144: Line 144:
 ===== Space orientation, startup position ===== ===== Space orientation, startup position =====
  
-The orientation of the flying space will follow the orientation of the OpenVR space but in more 'robotic' coordinate system (ie. Crazyflie wants Z to point up!). +The OpenVR uses different coordinate system than the Crazyflie. The Crazyflie coordinate system is used through out the Bitcraze code, but if you want to convert between the two, the following rotation is done from the OpenVR space to the Crazyflie coordinate system:
- +
-The following rotation is done from the OpenVR space to the Crazyflie coordinated system:+
 ^  Crazyflie  ^  OpenVR  ^ ^  Crazyflie  ^  OpenVR  ^
 |             -Z     | |             -Z     |
Line 152: Line 150:
 |              Y     | |              Y     |
  
-This allows to easily orient the Crazyflie when setting up the system with an HMD.+The Lighthouse deck has 4 receivers and can recover its orientation. The Crazyflie can be started in any orientation when using the lighthouse system.  
 + 
 +You can test if the positioning is working by starting the Crazyflie facing X and using the clients "Position hold" mode, this should drift a little bit (mostly in Z) due to an estimator bug, though you should be able to get a quite stable flight and be able to control the Crazyflie position with the gamepad. 
 + 
 +===== The number of basestations and frame synchronization =====
  
-While the Lighthouse deck has 4 receiver and so can recover its orientation, this is not implemented yetSosimilarly to when flying in the LPS it is very important to start the Crazyflie with a correct orientation. It should be started with the antenna in the direction of X positive: +The lighthouse deck works with one or two V1 basestations but the estimated position will be better and more stable with two basestationsWhen using two basestationsone of them may be occluded temporarily, and the Crazyflie will use the other one for positioning
-{{:doc:lps:crazyflie_isometric_drawing_2.png?300|}}+
  
-The safest way to verify the orientation of the space is to look at the estimated positionIn the client you can create new log block in "settings/logging configuration" containing "stateEstimate.x/y/z"You can then look at it in the plotter and move the Crazyflie around to understand how is X positive oriented:+The protocol for the lighthouse is composed of frames starting with sync pulses from the basestations. The sync pulses are used to identify which basestation the frame is originating from and this information is essential for correct positioningWhen one basestation is occluded, only sync pulses from the visible basestation will be available to the system, which is fine as long as the the system can keep track of the frames. If we loose track of the frames, for instance if both basestations are occluded, the system has to re-synch again to function, but this is quick process when the basestations are visible. 
 +Due to the design of the lighthouse protocol, visibility to both basestations is always required for synchronization or re-synchronization in a two basestation system.
  
-{{:doc:lighthouse:estimated_potision.png?400|}} 
  
-Once you have located X positive, you can test if the positioning is working by starting the Crazyflie facing X and using the clients "Position hold" mode, this should drift a little bit (mostly in Z) due to an estimator bug, though you should be able to get a quite stable flight and be able to control the Crazyflie position with the gamepad. 
  
  
doc/lighthouse/setup.txt · Last modified: 2020-05-12 14:35 by kimberly