Inertial navigation is an autonomous navigation system that does not rely on external information, is not easily disturbed, and can work all day long, so it is widely used in all walks of life. Among them, MEMS inertial navigation based on microelectromechanical system (MEMS) inertial sensors is an important branch of inertial navigation. Its system has the advantages of low cost, small size, low power consumption and strong impact resistance. It is widely used in autonomous driving, drones, unmanned ships and other fields. MEMS inertial sensors mainly include MEMS accelerometers and MEMS gyroscopes. They were first used in the automotive industry and defense industry on a large scale in the 1990s. They began to be used in consumer electronics such as mobile phones in the early 20th century. In the future, with the rapid development of 5G and the Internet of Things, there will be a wave of growth. At the same time, with the development of sensing technology, MEMS inertial navigation is also constantly changing... Under the trend of the Internet of Things, the demand for MEMS inertial sensors will increase significantly MEMS sensors are the perception basis and data source of new generation information technologies such as the Internet of Things, artificial intelligence, and 5G. Benefiting from the rapid development of new industries such as artificial intelligence, 5G, and the Internet of Things, the MEMS industry is expected to grow rapidly in the future. It is estimated that by 2030, the number of sensors connected to the Internet of Things will exceed one hundred trillion. Such a huge demand for sensors will bring lucrative market opportunities to sensor manufacturers. According to relevant market research data, the consumer electronics field accounts for the highest proportion in the global MEMS market structure, so MEMS sensors used in the consumer electronics field will usher in major opportunities. Among them, low-precision MEMS inertial sensors have been used in various consumer electronics, such as mobile phones, game consoles, wireless mice, digital cameras, pedometers, toy-level drones, smart sports equipment, etc., occupying most of the market share. The consumer electronics market is huge and involves many industries. With the further development of the Internet of Things, the use of smart hardware will increase significantly, and it is expected that the application demand for MEMS inertial sensors will increase significantly. High-precision MEMS gyroscopes will replace fiber optic gyroscopes In recent years, MEMS inertial sensors have developed rapidly and their accuracy has continued to improve. Although the accuracy is still far behind that of fiber optic gyroscopes and laser gyroscopes, their low price, small size and light weight make MEMS inertial navigation systems play an important role in inertial navigation systems. According to the accuracy, gyroscopes can be divided into commercial gyroscopes, tactical gyroscopes, navigation gyroscopes, and strategic gyroscopes. At this stage, the fastest growing market and technology is MEMS gyroscopes. Benefiting from the adoption of MEMS gyroscopes in smartphones, its market size has achieved tremendous growth. According to the analysis and forecast of gyroscopes in 2020 by the Draper Laboratory in the United States, in 2020, quartz/silicon micro-electromechanical MEMS gyroscopes will occupy medium and low-precision application areas, that is, consumer-level applications. The basic function is to measure the linear acceleration, tilt angle, rotation speed, vibration frequency and strength of an object. These basic physical signals can be derived into a variety of functions through the development of application programs. Development trend of gyroscopes in 2020 In addition, although the current strategic high-precision application fields (represented by aerospace and defense fields) are dominated by fiber optic gyroscopes. However, with the continuous development of MEMS material technology and manufacturing technology in the future, MEMS inertial sensors will develop in the direction of light weight and miniaturization, the accuracy of MEMS inertial navigation systems will continue to improve, and their costs will continue to decrease. Therefore, it is an important development trend to use strategic-level high-precision MEMS gyroscopes to replace fiber optic gyroscopes. Today, some high-precision MEMS inertial sensors are used in smart shells, optical aiming stabilization systems, underwater object navigation, aircraft attitude monitoring, battlefield robots, etc., and are the inevitable choice for guided weapon systems such as air defense missiles, anti-tank missiles, and portable missiles. It is estimated that by 2020, 90% of the guided weapons of the US military will use MEMS inertial sensors. MEMS inertial navigation and GPS combined navigation are still the mainstream. It is true that the accuracy of MEMS inertial sensors is constantly improving, but the error of tactical-level MEMS inertial navigation systems still diverges greatly over time, and in many occasions it cannot meet the requirements of high precision. Therefore, MEMS inertial navigation and GPS combined navigation are still the main navigation methods. With the assistance of GPS navigation information, the error of the inertial navigation system can be corrected, and the error divergence of the inertial navigation system can be effectively suppressed, thereby improving the accuracy of the entire navigation system. In general, we can use Kalman filtering algorithm, complementary filtering algorithm or neural network algorithm to fuse the data of two navigation systems and obtain the best navigation results. When GPS is not working, the use of inertial navigation alone can still ensure the normal operation of the system for a long time; high-precision GPS positioning can compensate for the error of inertial navigation. In addition, under the premise of the slow development of hardware processing technology, it is also an important development direction to study algorithms with higher accuracy, efficiency and robustness, and to support the combined navigation system in software. For example, at the beginning of this year, Japan's TDK company launched an inertial assisted positioning software Inven Sense Coursa Drive for autonomous driving platform developers to improve the accuracy of inertial navigation from the algorithm level. Coursa Drive not only reduces the accuracy of pure inertial vehicle positioning to 0.2% of the driving distance, which is crucial for maintaining decimeter-level vehicle positioning in challenging GNSS/perception system environments; it also provides high-speed position and direction information for autonomous driving vehicle systems, supplementing the low-speed position reference of GNSS and perception systems. In addition, Coursa Drive's offline mode reprocesses inertial navigation system data with an accuracy 2 to 3 times higher than the real-time mode, providing HD map companies with alternative position references to verify the accuracy of HD maps. Nowadays, high-precision combined navigation and positioning has become a "rigid need" for autonomous driving. Tunnels, urban canyons, elevated roads, and underground garages have always been the pain points of vehicle positioning. The reason is that when vehicles travel in the above complex environments, satellite signals are blocked or interfered, resulting in a decrease in positioning accuracy and even forming a blind spot for positioning. The inertial + GPS combined navigation system can solve these pain points, because inertial navigation can just make up for the shortcomings of satellite navigation positioning. The smoothing of GPS positioning data by inertial navigation information can effectively curb the trajectory drift problem, and the outdoor positioning trajectory is more continuous and smooth; the use of inertial navigation calculation can achieve autonomous and accurate positioning for a long time. Gathering mid-to-high-end MEMS inertial sensors is an inevitable choice for Chinese companies to break out. my country started late in the research of MEMS sensors. Although the technology has improved after years of efforts, there is still a clear gap with foreign countries, especially mid-to-high-end sensor technology. At present, many domestic users use relatively low-end products among high-performance MEMS inertial sensors that are not restricted for import from Western countries, such as Colibrys' accelerometers, Sensonor's gyroscopes, etc., and even use mid-range performance industrial-grade products, such as ADI's gyroscopes. Therefore, the user demand in the mid-to-high-end market is urgent. At the same time, in the mid-to-low-end market, due to the large number of competitors, the price of products has been declining, and the gross profit has been declining. In the past five years, the MEMS industry has been mainly driven by consumer electronics, and the shipment volume of MEMS devices has continued to rise. Later, as the size of MEMS devices continued to decrease, prices continued to fall, and profits gradually shrank, making the days of MEMS companies increasingly difficult. In such a market environment, increasing efforts to develop mid-to-high-end MEMS inertial sensors is one of the ways for my country to narrow the gap with foreign companies, and it is also an inevitable choice for Chinese companies to break out. In addition, seizing the new blue ocean market is also an opportunity for manufacturers to overtake on the curve. In the future, drones and virtual reality devices are expected to become new blue oceans for MEMS sensor applications. Many manufacturers have launched six-axis/nine-axis/ten-axis MEMS devices, and multi-integration MEMS devices are gradually gaining more favor. It has great application potential in the field of unmanned systems. MEMS inertial navigation has developed rapidly in the past few decades and has been increasingly used in the field of unmanned systems. As the main development direction of inertial navigation in the future, it is showing strong potential and good application prospects. UAV In recent years, micro-UAVs have played an increasingly important role in the military and civilian fields. In order to achieve the positioning and location of the UAV itself, the heading and attitude measurement and control system plays a vital role. The heading and attitude measurement and control system is mainly composed of GPS antenna, GPS receiving board, strapdown magnetic sensor, inertial measurement unit, altitude and airspeed sensor and conditioning unit. The accuracy of the sensor directly determines the accuracy of the UAV's position and attitude. The data collected by the sensor is used to calculate the position and attitude information of the UAV through the navigation algorithm. At present, the navigation of UAVs mainly adopts the means of combining MEMS inertial navigation system with GPS, which can not only improve the system accuracy, but also shorten the initial alignment time. The navigation system carried by UAVs today is of consumer grade accuracy, such as the accuracy of Invensense MP6500 is 2°/s. With the improvement of MEMS device accuracy and the reduction of cost, the navigation accuracy of UAVs will be improved in the future. Unmanned vehicle Unmanned vehicles use on-board sensors to sense the external environment and obtain vehicle position, attitude information and obstacle information, so as to control the vehicle's driving speed, steering, start and stop, etc. When the unmanned vehicle walks under a tall building and the GPS is blocked and cannot work normally, the accuracy of the inertial navigation system on the unmanned vehicle can meet the needs of the vehicle's autonomous movement in a short period of time. The MEMS inertial navigation system on the unmanned vehicle generally requires high accuracy. Unmanned ship Since the ordinary ship equipment used for tasks such as border patrols and water quality exploration is relatively dangerous and costly, the technology of unmanned ships has developed rapidly. Obtaining the position and attitude information of unmanned ships is an important prerequisite for unmanned ships to work autonomously. Today, the sensors equipped on unmanned ships mainly include GPS, MEMS inertial navigation systems and obstacle avoidance radars. With the improvement of the accuracy of MEMS inertial navigation systems, inertial navigation systems play a vital role in obtaining the position and attitude information of unmanned ships. The MEMS inertial navigation system carried on unmanned ships can meet the needs of general consumer-grade medium and low accuracy. In addition to being used in the environment in which we live, MEMS inertial navigation can realize various unmanned operations. In the future, as the accuracy and stability of MEMS inertial navigation continue to improve, MEMS inertial navigation technology will also be used in the aerospace field, such as spacecraft, satellites and other unmanned systems, and become an important member. Finally, in the intelligent era, inertial navigation with its autonomous characteristics just meets the needs of this era for "independent" and "intelligent" electronic hardware, and its prospects are promising.

--------------------- Author: Xiaoxiao Source: Sensor Expert Network Original text: //www.sensorexpert.com.cn/article/2987.html Copyright Statement: This article is compiled and published by Sensor Expert Network. Please indicate the source and link when reprinting!