DEVICE FOR OBTAINING SIGNAL DISPLAYING RELATIVE SPEED OF MISSILE TO PERIPHERAL FLUID ON MISSILE

摘要

PURPOSE: To reduce trouble by an arrangement wherein a filter is disposed between a measuring zone and a photodetector and the photodetectors of (n) wind vanes produce signals in at least two separating directions among the measuring axes thereof. CONSTITUTION: This apparatus comprises (n) wind vanes each generating a measuring zone having a measuring axis. Each wind vane has a laser diode 1 radiating a monochromic radiation which is passed through a collimator lens 2 to produce a beam. The beam is then separated 3 into beams A, B and converged through an emission lens 4 to a measuring zone M where fringes are formed. An optical filter 6 having the center of pass band at the radiation frequency of the diode 1 is disposed between the zone M and the photodetector 8 in order to removes the light other than the light emitted from the diode 1. When the filter 6 is not fitted, the detector 8 is saturated and the measurement can not be performed. Consequently, the photodetectors 8 of (n) wind vanes produce signals in at least two separating directions among the measuring axes thereof.