APPARATUS AND METHOD FOR MEASURING VELOCITY OF A PROJECTILE IN A BARREL

摘要

An apparatus for measuring avelocity of a projectile in a barrel includes a first optical fiber having a first and second fiber optic sensors mounted on the barrel and spaced apart. The sensors are connected to a tunable optical notch filter, which is in turn connected to a photodetector. The output of the photodetector is connected to a data processor which calculates the velocity of the projectile by measuring difference in time between hoop strains caused by the projectile's passing as measured by the sensors and the distance between the sensors. The tunable optical notch filter is tuned by a feedback circuit to compensate for changes in barrel temperature. This design allows portions of the system other than the two fiber optic sensors to be located remote from the barrel if desired.