Six-DoF MEMS sensor targets automotive

By Gina Roos, editor-in-chief

Murata Electronics’ new MEMS six-degrees-of-freedom (6DoF) inertial sensor combines an XYZ-axis gyroscope and XYZ-axis accelerometer with a digital SPI interface to provide bias stability and noise performance for safety-critical automotive applications. The SCHA600 allows for higher levels of advanced driver-assistance systems (ADAS) and automated driving (AD) functionality through data fusion with global navigation satellite systems (GNSS) and various perception sensors such as camera, radar, and LiDAR, said the company. GNSS integration delivers accurate positioning, and the frequently updated inertial data can be used to improve AD vehicle motion calculation.

The sensor’s performance has been optimized for use as a primary inertial measurement unit for AD, while the electronic stability control (ESC) unit provides redundancy. The SCHA600 enables centimeter-level accuracy for vehicle dynamics and position. It also features vibration robustness and extensive self-diagnostics.

Key specs:

• Component-level dynamic cross-axis calibration enables better than 0.3° cross-axis error over temperature
• Allan variance down to 0.9°/h at room temperature
• Gyro RMS noise level below 0.007°/s
• ±125°/s or ±300°/s angular rate measurement range to cover various application needs
• ±6 g acceleration measurement range
• −40°C to 110°C operating temperature range
• 3.0-V to 3.6-V supply voltage

The device’s patented self-test function verifies the proper operation of the entire signal chain — from MEMS sensor movement to signal-conditioning circuitry — for every measurement cycle, said Murata. The sensor is qualified according to the AEC-Q100 standard and is Automotive Safety Integrity Level (ASIL) D-compliant. The sensor is housed in a 32-pin SOIC package, measuring 18.7 × 8.5 × 4.5 mm.

In addition, Murata noted that the orthogonality of the measurement axes is calibrated at the manufacturing level, so system integrators can skip this costly step.

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