DETECTOR AND METHOD OF DETERMINING SPEED Russian patent published in 2012 - IPC G01P3/36 

FIELD: physics.

SUBSTANCE: device has a coherent light source which can generate a pair of incident beams of coherent light, wherein one beam is polarised relative the other and said beams are converged to a point, an optical imaging system configured to receive light reflected from a moving object which crosses the pair of incident beams, and focus the reflected light into a magnified image which is projected through an optical mask, as well as light detector configured to receive a light signal passing through the optical mask. The mask has a first region of alternating opaque and transparent areas, having a first spacing, and a second region of alternating opaque and transparent areas having a second spacing different from the first. Speed and direction of the moving object are calculated as a function of the frequency of pulses and spacing of opaque areas of the optical mask.

EFFECT: invention simplifies determination of speed and direction.

13 cl, 4 dwg