Highly Accurate Inclinometer Robust to Ultralow-Frequency Acceleration Disturbances and Applications to Autotracking Antenna Systems for Vessels

This paper describes a new inclinometer that compensates for ultralow-frequency acceleration disturbances. This inclinometer consists of a low-cost accelerometer, pendulum, and rotary encoder. The key feature of this inclinometer is the estimation method used to calculate the pendulum´s inertial angle. We propose two algorithms to estimate the pendulum´s angle. Algorithm I uses time-averaged accelerations and some assumptions. Algorithm II applies the pendulum´s equation of motion. The results of simulations and experiments confirm that both algorithms can achieve highly accurate level/angle estimations under acceleration disturbance conditions. We apply this inclinometer to an autotracking antenna system for vessels. Time simulations verify its effectiveness.