MEMS inertial measurement unit

With the rapid development of micromechanical manufacturing technology and the demand of all kinds of new military weapons and civil products, the field of inertia technology is undergoing a profound change.The new inertial instrument represented by Micro Electro Mechanical Systems (MEMS) manufacturing technology has been continuously developed and improved. By virtue of its small size, light weight, low cost, strong environmental adaptability, high reliability and long life and many other advantages, it has gradually entered the application field of medium and high precision inertial instruments from low precision commercial and consumer instruments, and has been widely used in a variety of modern new weapons and commercial fields depending on its inherent characteristics different from traditional mechanical instruments.The advanced industrial countries in the world have adopted the MEMS processing technology developed by the semiconductor industry to manufacture silicon-based MEMS inertial instrument, quartz based MEMS inertial instrument and micro-integrated optical gyroscope.

Compared with the traditional inertial instrument, MEMS inertial instrument has the following advantages:

(1) Made by semiconductor processing technology, the sensitive structure size is usually between micron and millimeter, and integrated with signal processing circuit size is usually in millimeter to centimeter, with small volume, light weight and low power consumption outstanding advantages;

(2) silicon is used as the processing material, which is compatible with the manufacturing process of microelectronics integrated circuit. The sensitive structure of MEMS inertial devices can be integrated with the signal processing circuit and control circuit on a chip, and the production cost of a single instrument can be significantly reduced through mass production;

(3) there is no high-speed rotor, suitable for redundancy configuration and high integration, which is conducive to reducing interference and improving reliability.

Based on the above advantages, silicon based MEMS with miniaturization, low cost, low power consumption, high reliability and high precision has become a hot spot in the field of autonomous navigation of military equipment.With the transition of silicon MEMS inertial devices from consumer inertial devices to tactical inertial devices, silicon MEMS inertial devices are gradually applied in military equipment navigation and guidance devices.However, due to the impact of scale effect on MEMS processing technology and packaging, the performance of MEMS inertial devices deteriorates in thermodynamic environment, which leads to the limited application of MEMS inertial devices in tactical missiles.

At present, the technical approaches to improve the accuracy of tactical silicon MEMS inertial devices are mainly from the error compensation suppression algorithm and process packaging hardware.The error compensation suppression is mainly for MEMS inertial sensor error analysis (including deterministic error and random error drift).Aiming at the deterministic error, the error model of MEMS inertial sensor is established, and the influence of deterministic error on MEMS inertial sensor is eliminated by calibration compensation or rotation modulation, so as to improve the accuracy and stability of MEMS inertial sensor.For random errors, the correlation of internal structure of MEMS inertial sensors of the same model batch is smoothed by array configuration or fusion filtering algorithm.Process packaging hardware needs to explore the process parameters, the application of new materials and other technologies, the cost is huge, the development cycle is long, difficult to achieve performance improvement in a short time.

ERDI LASER LTD’s MEMS inertial measurement unit adopts the same batch of low-cost MEMS chips, uses multi-sensor fusion algorithm to build MEMS array navigation system information processing system, and corrects the installation errors and sensor errors in real time during task execution by online calibration technology. At the same time, the fault detection technology is used to monitor the working state of the sub-sensors in the MEMS array in real time, and in the event of failure, fault isolation and processing are carried out in time.Based on MEMS array technology, high precision and high reliability measurement is realized.