Quaternion to HeadingPitchRoll


I have a entity from CZML datasource. I can get it’s position in Cartesian and orientation in Quaternion.

I have no problem to transform position to lat / lon using “Cesium.Ellipsoid.WGS84.cartesianToCartographic”.

However, I can’t figure out how to translate quaternion to heading/pitch/roll. (respect to an east-north-up axes centered at the entity position)

Anyone could help?

There doesnt appear to be a method for either quat or mat3 to convert into euler angles. You could convert into mat3 then do manual inverse trig on first column for yaw/pitch then the second or column for roll

I begun a pull in order to retrieve heading pitch roll from a quaternion:

Hi Bob,

Thank you for the HPR to Quaternion. But I still not sure how to further convert the generated HPR(respect to earth-center frame) into an east-north-up frame.