With MEMS motion-sensing hardware and software suppliers bringing a fertile cornucopia of
sensor/data fusion solutions to the marketplace, OEMs will be better equipped to augment motion-
sensing functionality in their end-user applications with far greater ease. In the end, however,
consumers will be the ultimate winners, as the mobile handset/tablet/e-reader/game controllers of the
near future will engage them in ways that we have only just begun to imagine.
(,(
By Jay Esfandyari, Roberto De Nuccio, Gang Xu,STMicroelectronics, Coppell, TX USA
,.1
(,(includeto measure linear acceleration and earth gravity
vectors,to measure angular velocity,to measure earth's magnetic fields
for heading determination andto measure the air pressure for altitude
determinations. The number of applications becomes very large by combining these components in
asolution. This paper explains how to make these sensors work together in a sensor
fusion solution by describing some examples using complementary filters; The4and
the.4(,4).
For applications such as freefall detection, screen rotation, pedometer, tilt measurement and motion
detection, etc., an accelerometer itself can perform the task. However, for other advanced applications
including location-based services, enhanced motion gaming, pedestrian dead reckoning navigation,
robot balancing, air mouse, human body tracking, unmanned aerial vehicles, etc., the fusion of(,(
is necessary to achieve better performance at the system level in terms of accuracy,
resolution, stability and response time.is a set of adaptive algorithms for prediction and
filtering. It takes advantage of different and complementary information coming from various sensors,
combining it together in a smart way to optimize the performance of the system and enable new
amazing applications.
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When designing a system using multiple MEMS sensors, it is important to understand the advantages
and disadvantages of,,, and.
Sensor fusion solves key motion sensing performance issues of 6-axis modules consisting of a 3-axis
accelerometer and a 3-axis gyroscope or a 3-axis accelerometer and a 3-axis magnetic sensor. 1) A 6-
axis inertial module with an accelerometer and a gyroscope loses its absolute orientation as the gyro
drifts over time, requiring calibration to restore accurate heading reference. 2) A 6-axis module with
accelerometer and magnetometer is prone to data corruption in the presence of ferrous materials in the
environment. 3) A#'.with an, aand
aeliminates the drift that occurs with stand-alone sensor solutions. But these can be
subject to magnetic interference. Algorithms to fuse the sensor data are required to compensate for the
magnetic interference.
The purpose of sensor fusion is to take each sensor measurement data as input and then apply digital
filtering algorithms to compensate each other and output accurate and responsive dynamic attitude
(pitch/roll/yaw) results.