落塔微重力水平激光干涉测量方法中的干扰因素分析

落塔是获得微重力环境的重要设施，落塔微重力水平的测量对微重力科学实验的研究至关重要. 激光干涉是测量落塔微重力水平的一种新方法，这种方法的基本原理是让一个参考落体在落舱中自由下落，落舱由于受到服外空气阻力的作用将与自由落体运动略有差异，1 11. 肫内的参考落体则更接近理想的自由落体运动，这就使得落舱与参考落体之间存在着加速度差，这种加速度差便反映了落服的微重力水平，其所导致的相对运动则可通过激光干涉的方法测量出来. 本文对落塔微重力水平的激光干涉测量方法中将会遇到的一些主要干扰因素进行了分析，计算结果表明，这些干扰网素所造成的总误差约为 1.2 x 10-7g，低于微重力水平的预测值 10-4~lO-6 g，因此该方法是一种比较可行的测量方法. 

Analysis of Disturbance in the Measurement of the Residual Acceleration of the Drop Capsule With the Laser Interferometry

Drop tower is an important facility to obtain microgravity environment. For the scientific experiments which will be performed in drop tower, it is quite important to know the residual acceleration of the drop capsule. Laser interferometry is a new method for measuring the residual acceleration of the drop capsule. The basic principle of this method can be described as following: a reference object falling in the drop capsule can fall more freely than the drop capsule itself because the outer air drag acts on the latter, so there is a difference of acceleration between the reference object and the drop capsule. The difference of the acceleration can be obtained according to the relative displacement which can be measured by laser interferometry. The main disturbance of this method is discussed in details. The total error caused by the main disturbance is 1.2 x 10-7 g, less than the estimated microgravity of 10-4~10 -6 g, so the laser interferometry is a suitable method for measuring the residual acceleration of the drop capsule.