This study aims to develop a precise sensor to realize a real-time measurement system for ground motion or dynamic behaviors of large structures. Our proposed sensor requires no electric power supply with using optical interferometry, which has an advantage of long-term measurement. In our previous study, we have confirmed the principle of the sensor. However, the sensor detects the motion of the inside mass part, not the motion of the sensor package. This paper describes an estimation method of the sensor package acceleration for practical use. A mathematical model of the sensor is built with spring-mass-damper system for the estimation of the sensor package acceleration. We compared the estimated acceleration with a result of servo accelerometer, and they showed good agreement. This means the possibility of practical use of the proposed sensor as a real-time accelerometer.
