The Lidar module is not documented, yet (and won’t be until I can fix a couple of issues with it).
However, the inputs and outputs between modules in the FAST framework are all in the global coordinate system (the only exception is AeroDyn v14, which we are hoping to replace).
LidPosition and MsrPosition are in this global coordinate system (with the origin being where the tower centerline intersects the ground; see pg 16 here). It looks like you’ve modified the code a little, because I’ve got
[code]u_IfW%lidar%MsrPosition = m_FAST%ExternInput%LidarFocus + u_IfW%lidar%LidPosition
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The LidarFocus is an input from Simulink (if it’s used), and that is relative to the lidar position. The idea, I believe, was that the scanning pattern could be easily modified in Matlab and sent through the Simulink interface. At some point, I would love to put options for scanning patterns in InflowWind.
InflowWind returns the wind speed in the same FAST coordinate system as the lidar positions are specified (i.e., UVW are aligned along XYZ in the FAST global system), so no coordinate transfer is necessary before calling InflowWind. The returned lidar speed (LidSpeed) takes into account the direction the lidar is pointing.