Calibration of the three-axis accelerometer navigation unit in operation on low precision equipment

Abstract

A method for calibrating a three-axis accelerometer unit of the navigation accuracy class is proposed. It is based on measuring the modulus of the gravity acceleration vector. The method provides the determination of twelve passport coefficients (including six separate values of non-orthogonality angles) of the linear metrological model of a stationary accelerometer unit under operating conditions. The developed method makes it possible to calculate the acceleration value with an acceptable error using non-precision equipment for calibration. The problem is solved by forming a system of linear nonhomogeneous algebraic equations for the desired differences of unknown actual (real) values and the passport values of an accelerometer unit's metrological model coefficients. The passport coefficients are considered to be determined during bench calibration at the manufacturer. The system of equations is formed by placing the accelerometer in at least nine calibration positions relative to the gravity vector. The solution of this system, with consideration of the limitations formed by the six additional calibration positions of the accelerometer unit, allows determining the actual values of the metrological coefficients of the accelerometer unit and using them as passport values. By reducing the reliance on expensive and complex calibration equipment, the developed method offers a cost-effective solution for maintaining the long-term accuracy and performance of the accelerometer unit over its operational lifetime. The versatility of this calibration approach enables its integration into existing manufacturing processes, ensuring consistent and reliable performance of accelerometer units across different batches, thereby enhancing the overall quality and reliability of navigation systems and related technologies.