Sensor Fusion algorithm and API for STM32
Features
■ Absolute point tracking and motion tracking
accuracy
■ Immunity to magnetic interference for high
performance in real-world conditions
■ Few user-calibration interruptions, enabling
innovative and longer game play
■ Reliable compass heading for accurate
navigation
■ Accurate direction enabling true augmented
reality applications
■ Support for STM32F103 microcontrollers
■ Full tunability
■ Embedded calibration
iNEMOEngine_PI3P
iNEMO Engine Pro
Data brief
iNEMOEngine_PI3P
Description
The iNEMO engine is a new, advanced software
engine that fuses accelerometer, gyroscope and
magnetometer data to deliver accurate and
reliable motion-sensing information that is easy to
integrate into smart consumer devices.
The iNEMOEngine_PI3P software pack comes
with the iNEMO Engine as a precompiled library
for STM32F103 microcontrollers and with API
example code for algorithm setup and tuning.
October 2011 Doc ID 022209 Rev 2 1/6
For further information contact your local STMicroelectronics sales office.
www.st.com
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iNEMO Sensor fusion iNEMOEngine_PI3P
1 iNEMO Sensor fusion
1.1 Overview
The iNEMO engine is a new, advanced software engine that fuses accelerometer,
gyroscope and magnetometer data to deliver accurate and reliable motion-sensing
information that is easy to integrate into smart consumer devices.
Figure 1. 9-axis sensor fusion
Magnetometer
Gyroscope
Accelerometer
SW libraries
9-axis sensor fusion
1.2 How the iNEMO engine works
The iNEMO engine fuses data from the integrated 9-axis sensor suite with advanced
algorithms that use true high-number-of-states adaptive Kalman filtering.
The iNEMO engine’s adaptive filters converge so correct heading data overrides magnetic
distortions and anomalies, resulting in more accurate and reliable data.
iNEMO allows the correction of:
● magnetic distortions registered on the magnetometers
● dynamic distortion measured by the accelerometers
● inherent drift of the gyroscope over time
AM10211V1
The iNEMO engine integrates all 9 inertial axes plus compass with complex fusion
algorithms, so the output of the sensor cluster is optimized.
This allows for faster, easier integration into smart consumer devices and higher
performance of the solution as a whole.
The library can be configured to achieve the best tradeoff between performance and powersaving to match application requirements.
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iNEMOEngine_PI3P Input and output data
2 Input and output data
Figure 2. Sensor fusion input and output
Inputs OutputsInputs Outputs
2.1 Sensor fusion algorithm input
The iNEMO engine API is based on 9-axis sensor fusion suite.
Required input:
● Accelerometer output data: x,y,z
● Gyroscope output data: yaw, pitch, roll
● Magnetic sensor output data x,y,z
● LIbrary configuration parameters
2.1.1 Sensor orientation
iNEMO engine API sensor orientation is compatible with the reference system defined by
Android (east, north, up).
2.2 Output
The iNEMO engine software libreries fuses data from the integrated 9 axis sensor suite with
an advanced algorithms based on a true adaptive Kalman filter to obtain precise error
modeling, outstanding accuracy prediction, magnetic distorsion correction.
AM10212V1
Doc ID 022209 Rev 2 3/6
System specifications and settings iNEMOEngine_PI3P
Libraries output:
● Quaternions four number hpr system
● Rotation: heading, pitch, and roll
● Linear acceleration: device frame linear accelerations
● Gravity: device frame gravity acceleration
3 System specifications and settings
3.1 Typical sensor settings
3.1.1 Sensor full scales
● Accelerometer: 2 g
● Gyroscope: 2000 dps
● Magnetometer: 8.1 gauss
3.1.2 Sensor ODR
● Gyroscope: 100 Hz
● Accelerometer: 100 Hz
● Magnetometer: 75 Hz
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iNEMOEngine_PI3P Revision history
4 Revision history
Table 1. Document revision history
Date Revision Changes
09-Sep-2011 1 Initial release.
Added Section 2: Input and output data and Section 3: System
26-Oct-2011 2
specifications and settings.
Minor text changes.
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iNEMOEngine_PI3P
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