PULSED HETERODYNE CO2-LASER RANGEFINDER AND VELOCIMETER WITH CHIRP CORRECTION

A pulsed hybrid CO2 transversely excited atmosphere (TEA) laser has be en used in a bistatic laser rangefinder-velocimeter system with hetero dyne detection. Several techniques have been applied to improve the pe rformance of the system. These include the stabilization of the hybrid CO2 TEA-laser and the stabilization of the frequency offset of the lo cal oscillator (better than +/- 74 kHz peak to peak), phase-front matc hing at the detector surface resulting in a heterodyne beat efficiency of 0.4-0.6, and chirp correction. With this system, targets at distan ces of up to 25 km can be detected with an accuracy of 15 m. The veloc ity of the targets can be estimated with an accuracy of approximately +/- 0.5 m/s.