| CPC G01S 7/4817 (2013.01) [G01S 7/4813 (2013.01); G01S 17/89 (2013.01); H02K 11/0094 (2013.01); H02K 11/33 (2016.01); G01S 17/931 (2020.01); G01S 17/933 (2013.01)] | 10 Claims | 

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               1. A method comprising: 
            rotating two or more laser beams around an axis of rotation, each of the laser beams having a wide dimension in a first plane and a relatively narrow dimension in a plane at right angles to the first plane, each of the laser beams having different orientations from each other, the wide dimension being 0.05-50° and the narrow dimension being 0.1-10.0 mrad, and there being an angular separation between the laser beams in the plane at right angles to the axis of rotation; 
                tracking, by an encoder, a horizontal angle between the two laser beams based on the different orientations relative to an object; and 
                calculating a vertical position of the object using the angular separation of the two laser beams. 
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