초록 ▼

A laser distance measuring apparatus in which source beams from two lasers are combined and focused on a target. One beam is continuous wave and one has periodic narrow pulse envelopes. After reflection the composite reflected beam is redivided in a diffraction grating and compared with two respecti

A laser distance measuring apparatus in which source beams from two lasers are combined and focused on a target. One beam is continuous wave and one has periodic narrow pulse envelopes. After reflection the composite reflected beam is redivided in a diffraction grating and compared with two respective reference beams by means of two photodetectors. Doppler data are provided, as well as separate high resolution and low resolution range output data. Integration of the Doppler data in a computer, and combination of the three data signals there, enable an unusually complete and accurate record of the shape of the target even if the shape has many severe discontinuities, as in the case of a turbine rotor. An alternative embodiment provides for switching the pulse time of flight portion of the system to utilize various harmonics of the pulse envelope waveform. Known phase delays are switchably interposed in one channel so that relative phase readings between the reference and target pulses are performed at near-zero phase differences. Phase readings can be made accurately when the signals possess near-zero phase differences. Fixed errors can be measured and calibrated out of measurement data.

대표청구항 ▼

Laser distance measuring apparatus for measuring distances to points on a target object, comprising: a source of a pulse laser beam; a source of a CW laser beam; splitting means for providing a reference beam and a target beam from said pulse laser beam; splitting means for providing a reference bea

Laser distance measuring apparatus for measuring distances to points on a target object, comprising: a source of a pulse laser beam; a source of a CW laser beam; splitting means for providing a reference beam and a target beam from said pulse laser beam; splitting means for providing a reference beam and a target beam from said CW laser beam; means for combining said pulse target beam and said CW target beam to provide a composite target beam for measuring distances to points where the target beam impinges upon the target object; scanning means for controllably directing said composite target beam to illuminate a point on the target, said scanning means comprising dwell means for holding said composite target beam at an area of the target to obtain a greater density of distance measurements, especially where information of higher accuracy is desired; computer means for processing data of distance measurements to utilize the redundancy of the greater density of data to increase the accuracy where said higher accuracy is desired; means receiving the composite beam after reflection from the target, for separating the reflected pulse target beam component from the reflected CW target beam component; frequency discriminator means for measuring Doppler frequency shift of the CW target beam relative to said CW reference beam and providing Doppler shift data; integration means for integrating said Doppler shift data to provide relative distance data; phase comparison means measuring the phase difference between said reflected pulse target beam component and said pulse target reference beam, for acquiring target distance data based upon the time of flight of a pulse; computer means combining said pulse data and said Doppler data for providing output data, said output data comprising distance measurements corresponding to points on the target object at which said controllably directed composite beam impinges upon said target object.