1 June 2010 High-resolution rangefinder with a pulsed laser developed by an undersampling method
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A high-resolution rangefinder equipped with a pulsed laser has been developed by introducing a high-resolution interpolation technique based on an undersampling method. Using this pulse method employed by the rangefinder, a new time-scale expansion has been realized that is similar to the heterodyne of the rangefinder that also employs the phase difference method. Therefore, high-resolution measurements are now possible. A bandpass-filtered temperature-compensated crystal oscillator signal with a reference frequency of 15 MHz is sampled at a timing determined by a received pulsed light with a repetition rate of 8.5 kHz. With this process, a time series of undersampled 2.5-kHz data are obtained as an intermediate step that can be further lowered to 85 Hz by final rearrangement of the undersampled data. With this technique, a reference frequency is transformed into a lower frequency. A distance is then calculated from the phase of this low frequency. The rangefinder developed shows good performances that include a range resolution of better than 1 mm, nonlinearity within ±1 mm, and a measurement range of up to 7000 m.
© (2010) Society of Photo-Optical Instrumentation Engineers (SPIE)
Masahiro Ohishi, Masahiro Ohishi, Fumio Ohtomo, Fumio Ohtomo, Masaaki Yabe, Masaaki Yabe, Mitsuru Kanokogi, Mitsuru Kanokogi, Takaaki Saito, Takaaki Saito, Yasuaki Suzuki, Yasuaki Suzuki, Chikao Nagasawa, Chikao Nagasawa, } "High-resolution rangefinder with a pulsed laser developed by an undersampling method," Optical Engineering 49(6), 064302 (1 June 2010). https://doi.org/10.1117/1.3456624 . Submission:

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