Improve description of model section #2
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alexshalamov
commented
Mar 7, 2017
alexshalamov
commented
- Improve description of model section
- Add graphical example for relation of Earth's and device's coordinate systems
index.bs
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| The elements of the [=list=] are equal to components of a unit quaternion representing orientation | ||
| of the device in a three dimensional Cartesian coordinate system (x, y, z), where x-axis points east, | ||
| y-axis points north and z-axis points up and is perpendicular to the plane made up of x and y axis. | ||
| The elements of the [=list=] are equal to components of a unit quaternion [cos(θ/2), x**sin(θ/2), y*sin(θ/2), z*sin(θ/2)] |
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Could you add a ref for "unit quaternion"?
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maybe better [cos(θ/2), Vx sin(θ/2), Vy sin(θ/2), Vz sin(θ/2)], where V is the unit vector representing the axis of rotation
- Improve description of model section - Add graphical example for relation between Earth's and device's coordinate systems
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LGTM. Bonus points for referencing my favourite paper. |
| y-axis points north and z-axis points up and is perpendicular to the plane made up of x and y axis. | ||
| The elements of the [=list=] are equal to components of a unit quaternion [[QUATERNIONS]] | ||
| [cos(θ/2), V<sub>x</sub> * sin(θ/2), V<sub>y</sub> * sin(θ/2), V<sub>z</sub> * sin(θ/2)] where V is the unit vector representing | ||
| the axis of rotation. The quaternion represents rotation of a device hosting motion sensors in relation to a <dfn>Earth's reference coordinate system</dfn> defined as a three |
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Maybe say that the first component is the scalar representing the actual rotation angle
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| - x-axis is a vector product of y.z that is tangential to the ground and points east. | ||
| - y-axis is tangential to the ground and points towards magnetic north. | ||
| - z-axis points towards the sky and is perpendicular to the plane made up of x and y axes. |
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So the z-axis would normally be called a normal vector of that plane
| @@ -18,18 +18,53 @@ Version History: https://github.com/w3c/orientation-sensor/commits/gh-pages/inde | |||
| Indent: 2 | |||
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the perspective of the phone sides on that picture in comparison with the earth, looks all wrong. The phone looks like it lays flat on the surface, but the sides tell another story... the sides should be parallel with the z axis
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I can improve it later if required, or you can open issue or PR. Thanks.
