Device for adopting linear frequency modulation double beam laser heterodyne method and torsional pendulum method to measure micro impulse and measuring method thereof

The invention relates to a device for adopting a linear frequency modulation double beam laser heterodyne method and a torsional pendulum method to measure micro impulse and a measuring method thereof and belongs to the field of micro impulse measurement. The problem that existing devices and methods for micro impulse measurement are low in measurement precision is solved. The linear frequency modulation double beam laser heterodyne method is applied to the micro impulse measurement method, measurement of the micro impulse is converted into measurement of a standard beam torsional pendulum angle, information of the to-be-measured standard beam torsional pendulum angle can be obtained indirectly through the measurement of the thickness of a plane standard lens, measurement accuracy is effectively improved, the measured micro impulse and the incidence angle theta 0 form linear relations when the turning angle is small (smaller than 5 degrees), the measuring error is smaller than 0.52%, the requirements of impulse measurement of a laser micro thruster can be met, and a good measurement means is provided for evaluating the performance of the laser micro thruster. The device and the measuring method are mainly applied to evaluation of the laser micro thruster.