Amid the rapid development of autonomous driving technology, Advanced Driver Assistance Systems (ADAS) have become the core of automotive intelligence and safety evolution. Beyond external environmental perception devices like cameras, millimeter-wave radar, and LiDAR, inertial sensors that capture the vehicle's own status in real-time are equally indispensable. Among them, the Inertial Measurement Unit (IMU), composed of a gyroscope and an acceleration sensor, can precisely provide data on vehicle acceleration, yaw rate, and attitude changes, offering fundamental support for functions such as Lane Keeping, Electronic Stability Control, Adaptive Cruise Control, and Automatic Emergency Braking. As ADAS progressively advances towards higher levels of autonomous driving, how to improve the accuracy, reliability, and multi-sensor fusion capabilities of inertial sensors has become one of the important solutions for the industry to achieve safe and intelligent driving. This article will introduce the development history and system architecture of ADAS, as well as the functional characteristics of the IMU solution composed of gyroscopes and acceleration sensors launched by Murata.
The development history and system architecture of ADAS
ADAS has undergone years of development. In its early stages (around 2000), it primarily focused on single functional assistance, such as ABS (Anti-lock Braking System), ESC (Electronic Stability Control), and Cruise Control. Sensors were mostly radar-based, providing basic collision avoidance and distance control. Around 2010, it entered a functional expansion phase, introducing cameras, millimeter-wave radar, and ultrasonic sensors, beginning to implement Lane Departure Warning (LDW), Blind Spot Detection (BSD), and Automatic Emergency Braking (AEB). Systems gradually evolved from single-function to multi-function integration.
Around 2020, ADAS moved towards an intelligent and fusion stage, featuring multi-sensor fusion. For example, combining radar, cameras, and ultrasound, and introducing AI algorithms enabled semi-autonomous driving functions like Level 2 autonomous driving (highway auto cruise, lane keeping assist). The future will transition towards advanced assistance and autonomous driving, developing towards Level 3 and above autonomous driving, requiring high-precision maps, V2X (Vehicle-to-Everything), and higher-computing-power automotive AI chips. The system architecture tends towards centralization (centralized ECU / domain controller) to support more sensors and algorithms.
The ADAS system architecture can generally be divided into three main parts: the Perception Layer, the Decision Layer, and the Actuation Layer. The Perception Layer includes sensors such as cameras (front-view / surround-view / in-cabin), millimeter-wave radar (short-range / mid-range / long-range), ultrasonic sensors, and LiDAR (for advanced ADAS or L3+ autonomous driving). Its function is environmental perception (object detection, lane recognition, pedestrian identification, obstacle detection).
The Decision Layer includes the core control unit (ECU / domain controller), covering sensor fusion algorithms, AI / deep learning models (for pedestrian, vehicle, traffic sign recognition), path planning, and decision logic. Functionally, it is used to make driver assistance or autonomous driving decisions.
The Actuation Layer includes vehicle control units, such as braking systems (ABS/ESC/AEB), steering systems (Electric Power Steering EPS, Lane Keeping), and powertrain systems (throttle control, intelligent cruise). Functionally, it is used to actually execute control commands, ensuring vehicle dynamic stability and driving safety.
The development of ADAS has gradually evolved from single-function assistance to multi-sensor fusion and AI-driven intelligent architecture, ultimately moving towards Level 3 and above autonomous driving. Its system architecture covers the three major layers of Perception-Decision-Actuation, with the core lying in the application of multi-sensor fusion and high-efficiency computing platforms.
The role of gyroscopes and acceleration sensors in ADAS applications
The gyroscope and acceleration sensor are important components in ADAS applications. The acceleration sensor measures the vehicle's acceleration in the X, Y, and Z axes, allowing for the calculation of speed changes and the impact force at the moment of a collision. The gyroscope measures the vehicle's angular velocity (yaw, pitch, roll), determining steering angle, attitude changes, and lateral and longitudinal dynamics. The two are often integrated in the form of an IMU to provide high-precision vehicle dynamic information.
In ADAS, gyroscopes and acceleration sensors are often used in Vehicle Dynamics Control (VDC). The acceleration sensor monitors lateral acceleration, detecting skidding or loss of traction, while the gyroscope measures the yaw rate, judging oversteer or understeer. They can integrate with the Electronic Stability Control (ESC) system to automatically adjust braking and power output to prevent loss of control.
In Automatic Emergency Braking (AEB) and collision detection applications, the acceleration sensor can accurately detect impact at the moment of collision, quickly triggering airbags. When combined with radar/camera data, it can pre-emptively decelerate before a collision.
In Lane Keeping Assist (LKA/LKS) and Lane Departure Warning (LDW) applications, the gyroscope monitors vehicle directional stability, helping to identify if the vehicle is drifting out of the lane due to driver operation or external forces. When fused with the camera's lane line detection, it can more accurately determine if the vehicle is deviating from the lane.
In Adaptive Cruise Control (ACC) and autonomous driving navigation applications, the acceleration sensor provides real-time data on vehicle acceleration and deceleration, improving the smoothness of cruise control. The gyroscope can work with GPS for high-precision positioning and attitude correction, avoiding drift errors inherent in GPS alone.
In parking assistance and low-speed autonomous driving applications, the IMU (acceleration + gyroscope) provides relative position and attitude information in low-speed or GPS-weak environments (like underground parking lots), assisting the vehicle in completing parking maneuvers.
Within the ADAS architecture, gyroscopes and acceleration sensors are key fundamental sensors belonging to the Perception Layer. They complement cameras, millimeter-wave radar, and LiDAR by providing information about the "vehicle's own state" rather than the external environment. After being fused by algorithms in the Decision Layer (ECU / domain controller), they output vehicle dynamic parameters, further driving the actuation layer's braking, steering, or acceleration control.
Gyroscopes and acceleration sensors play a crucial role of "vehicle dynamic perception" in ADAS. They provide real-time information on body attitude, acceleration, and yaw rate, assisting in core functions such as vehicle stability control, collision detection, lane keeping, automatic cruising, and precise positioning. Especially in scenarios not fully covered by cameras and radar, they provide critical redundancy and safety assurance.
IMU modules contribute to high-precision measurement data for ADAS
There are several levels of autonomous driving functionality, but all require highly accurate sensing and algorithms for processing the obtained data in an integrated manner. In its development of products for advanced driver assistance systems and autonomous driving systems, Murata conducts driving tests using a test vehicle equipped with an IMU module developed in-house. It uses the data to evaluate and verify safety in various anticipated use cases. Through its product portfolio enabling low-cost and precise measurement, Murata contributes to the crucial enhancement of measurement data accuracy for automotive autonomous driving.
Taking Murata's automotive integrated 6DoF gyroscope and acceleration sensor – the SCH1600 – as an example, the SCH1600 sensor is an optimal single-package 6DoF component. It is used for ADAS functionality and Autonomous Driving (AD) through data fusion with GNSS and various perception sensors such as cameras, radar, and LiDAR.
The SCH1600 sensor offers leading performance in angle random walk and bias stability in the market, ensuring high-quality gyro signal generation even within integration times of just a few seconds. Its fast data rates, time synchronization features, and high performance enable efficient sharing of IMU signals across all subsystems within the vehicle, from HUD control to camera and headlight leveling systems.
High-precision IMU solutions meeting stringent functional and safety performance
The Murata SCH1600 incorporates over 200 internal monitoring signals, achieving a high level of functional safety performance in the market. The orthogonality of the measurement axes is calibrated at Murata, allowing system integrators to bypass this costly and performance-critical process step.
The SCH1600 sensor family offers greater flexibility for advanced customers through redundancy design options and built-in adjustable dual output channels. It supports an angular rate measurement range of ±300°/s and an acceleration measurement range of ±8g, featuring a redundant digital accelerometer channel with a dynamic range up to ±26g. Gyro bias instability is as low as 0.5°/h, and angle random walk can be as low as 0.03 °/√Hz. It provides options for output interpolation and decimation, and includes functions like Data Ready output, Timestamp index, and SYNC input for clock domain synchronization. It operates within a temperature range of −40 to 110°C, supports a supply voltage of 3.0 to 3.6V and an I/O supply voltage of 1.7 to 3.6V, and features a SafeSPI v2.0 interface. Output data of 20-bit and 16-bit can be selected via the SPI frame. It includes extensive self-diagnostic features utilizing over 200 monitoring signals. The dimensions are 11.8mm x 13.4mm x 2.9mm (l x w x h), using an SOIC-24 inverted housing. It is qualified according to AEC-Q100 Grade 1 and comes in a robust, RoHS-compliant SOIC plastic package suitable for lead-free soldering processes and SMD mounting, utilizing proven capacitive 3D-MEMS technology.
The SCH1600 series is designed to serve as the central vehicle IMU, providing high-quality signals to all subsystems within the vehicle, even in very harsh environments. Representative application areas include Advanced Driver Assistance Systems (ADAS), Autonomous Driving (AD) and short-term Dead Reckoning (DR), GNSS, camera and radar fusion, inertial navigation, advanced vehicle stability control, and dynamic and static headlight leveling. Murata also offers the SCH1600 Chip Carrier PCB, designed to enable rapid prototyping. It includes the SCH1600 sensor soldered onto a PCB, with the PCB design (#MFI01398) including pin headers and passive components.
In the automotive application field, Murata offers numerous products applicable to ADAS ECU (Advanced Driver Assist Systems ECU), Parking Systems, LiDAR, RADAR, Sensing Cameras, and In-cabin Monitoring Systems. Taking the product lineup for automotive ADAS ECU as an example, it includes a series of product lines applicable to areas such as SoC, DC-DC/PMIC, Baseband, SerDes, CAN Transceiver, Ethernet, and Clock. These include ceramic capacitors, chip ferrite beads, thermistors, power inductors, chip inductors (chip coils), chip common mode choke coils, gyro sensors, ceramic resonators (CERALOCK), crystal units, etc., meeting the diverse needs of automotive applications.
Conclusion
In Advanced Driver Assistance Systems, gyroscopes and acceleration sensors are not only the foundation of vehicle dynamic perception but also key elements ensuring driving safety and enhancing the intelligent driving experience. By providing high-precision acceleration and attitude information, they complement external sensing technologies like cameras, radar, and LiDAR, enabling stable decision-making and control under multi-sensor fusion. As autonomous driving levels increase, future solutions will place greater emphasis on sensor high reliability, low power consumption, and AI fusion capabilities, thereby building a more efficient and safer intelligent mobility ecosystem for vehicles. The gyroscopes and acceleration sensors offered by Murata, with their high precision and stability, represent one of the optimal solutions for ADAS and autonomous driving applications.