1. The Unique Independence of IMU
Autonomous vehicles rely on a variety of perception sensors for environment awareness and positioning, including LiDAR, radar, cameras and high-precision maps. However, all these sensors depend on external environmental signals and visual feedback, which makes them susceptible to interference from weather, shelters, light changes and complex road conditions, easily leading to performance degradation or temporary failure.
Different from all external perception devices, the Inertial Measurement Unit (IMU) works completely independently. It does not rely on external signals or environmental data. This unique independence makes IMU the core guarantee for autonomous driving safety and multi-sensor fusion, serving as the most reliable redundant backup for vehicle positioning and attitude estimation.
2. Full-Dimensional Precision Positioning Capability
A standard automotive IMU integrates a three-axis accelerometer and a three-axis gyroscope, forming a complete 6-degree-of-freedom (6 DOF) sensing system. It can fully capture all motion states of the vehicle, including three-dimensional linear displacement and three-dimensional rotational changes (roll, pitch, yaw).
Beyond basic vehicle stability control and airbag triggering functions, IMU supports real-time tracking and continuous solving of vehicle position and attitude. After precise temperature calibration and drift compensation, combined with Extended Kalman Filter (EKF) algorithm, IMU can realize high-precision independent positioning in a short time. Advanced vehicle systems further fuse wheel speed and steering angle data to optimize the filtering algorithm, effectively improving positioning smoothness and accuracy.
3. Critical Safety Redundancy for Autonomous Driving
Autonomous driving system design strictly follows the FMEA (Failure Mode Effects Analysis) standard, requiring complete fault backup solutions for extreme scenarios. One of the core safety challenges is handling the simultaneous failure of LiDAR, radar and camera perception systems.
In extreme sensor failure scenarios, IMU enables dead-reckoning navigation. It can independently maintain stable vehicle position and attitude output within a certain period. Relying on continuous inertial data, the system can perform controlled deceleration and safe parking, avoiding sudden failures and dangerous driving states. This is an indispensable safety bottom line for mass-produced autonomous driving systems.
4. GNSS + IMU Combined Navigation: Mainstream High-Precision Solution
Traditional low-cost single-frequency GPS receivers cannot meet the high-precision positioning requirements of autonomous driving. In recent years, low-cost multi-frequency GNSS chips have been widely applied. Combined with RTK, PPP and other network differential correction technologies, GNSS positioning accuracy can reach centimeter level under open and ideal conditions.
However, GNSS signals are extremely vulnerable to occlusion by buildings, tunnels, bridges and dense vegetation, resulting in signal loss and sharp accuracy degradation. The core solution to this problem is GNSS/INS fusion technology, which uses high-performance IMU to fill the positioning gap during GNSS signal anomalies.
GNSS features absolute positioning accuracy but low update frequency (1–20 Hz) and poor continuity. In contrast, IMU supports high-frequency sampling and continuous output. It can interpolate positioning data between GNSS updates to achieve smooth and high-frequency positioning output. In complex sheltered scenarios, IMU can maintain effective dead-reckoning for 10 to 30 seconds.
Current mainstream automotive-grade MEMS IMUs have a gyro bias instability of 5°/h and an angular random walk of 0.5°/√h, which can ensure smooth positioning during GNSS refresh intervals. Yet they struggle to maintain centimeter-level accuracy for a long time in fully blocked scenarios such as tunnels. The next-generation high-performance MEMS IMUs are targeting indicators of 1°/h bias instability and 0.1°/√h angular random walk, which will fully meet the long-term high-precision fusion navigation needs of high-level autonomous driving.
5. Industry Challenges & Development Outlook
Consumer and industrial MEMS sensors allow a certain failure rate, but automotive-grade IMUs require ultra-high reliability, long service life and extreme environmental adaptability. High stability, low drift and high fault tolerance have become the core technical thresholds for vehicle-mounted inertial devices.
As the core underlying hardware of autonomous driving, IMU and INS inertial navigation technology are inconspicuous but indispensable. With the continuous iteration of MEMS technology and fusion algorithms, high-performance vehicle-mounted IMUs will further improve the safety, stability and reliability of intelligent driving systems.
6. Product Introduction: LIKOV MG-200 MEMS IMU
Core Advantages
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Full-temperature calibration and compensation, adapting to extreme temperature environments from -45℃ to +80℃
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100% domestic independent controllable components
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High performance, miniaturization, light weight and low power consumption
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Strong resistance to harsh mechanical vibration and impact
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1KHz high-speed sampling, supporting high-dynamic motion tracking
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Support online software upgrade, convenient for iterative optimization
Core Accuracy
Gyro bias instability: 0.3°/h (10s smoothing), reaching high tactical-grade performance.
Typical Applications
Autonomous vehicles, attitude reference systems, guidance and control systems, ship and vehicle attitude measurement, inertial/satellite combined navigation, drilling and mining systems, mobile mapping, satellite communication mobile terminals, seeker stabilization systems.
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