This document discusses how MEMS sensors can be used for navigation applications. It outlines that as GPS signals become obstructed, sensors like accelerometers, barometric pressure sensors, geomagnetic sensors and gyroscopes can be used together in hybrid systems for pedestrian navigation. The document also notes that many smartphones already have the necessary sensors built-in at low cost, and that indoor navigation is now feasible pending software and map solutions. Component miniaturization has been a key driver of lower MEMS sensor prices enabling these applications.

1. MEMS sensor based navigation
Steve Wahl
Sales Director North America
June 23, 2010
Bosch Sensortec
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2. MEMS sensors for navigation support
Pedestrian navigation cases
GPS reception environments
Good GPS signal Obstructed GPS signal No GPS signal
- Position by GPS - Hybrid GPS & Sensors - Multi-sensor navigation
- Accurate altitude by bar. navigation - Opportunity signals
pressure sensor - Mutual recalibration - Flexible hand-over
Increasing complexity and system cost
Bosch Sensortec
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3. MEMS sensors for navigation support
MEMS sensor use cases
 Accelerometers for device position & motion detection:
 Detect motion patterns like walking, running, sitting, laying down…
 Detect “no motion” trigger sleep mode for device power saving
 Detect “start of motion” system wake up, alarm, start fix…
 Detect device position relative to g-vector – eCompass, mute
device, rotate display, turn off display…
 Detect step frequency (of user) and derived stride length thus
provide traveled distance.
Multi use-case per sensor are the key for reducing cost / function
Bosch Sensortec
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4. MEMS sensors for navigation support
MEMS sensor use cases
 Barometric pressure sensors provide:
 Air pressure for altitude deduction (barometric formula & reference)
the most accurate means to achieve this at 0.25 m altitude resolution
 Accurate altitude enables indoor navigation by providing floor
level detection.
 Accurate altitude signals improves GPS accuracy in obstructed signal
environments.
Barometric pressure sensors are the solution for altitude detection
Bosch Sensortec
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5. Header of section
Navigation with pressure sensor
 Purposes:
 Altitude correction by weak GPS reception (by pressure)
 Floor detection is based on altitude measurement (by pressure)
 SW based error suppression:
 weather drift suppression,
 cancellation of pressure fluctuation
 Noise filtering
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6. MEMS sensors for navigation support
MEMS sensor use cases
 Geomagnetic sensors & gyroscopes:
 Geomagnetic sensors provide a heading even if no motion.
This allows for automatic map orientation & direction indication
 Gyroscopes provide accurate short term turn information.
This allows for accurate turn angle detection.
Geomagnetic sensors & gyroscopes rely on accelerometer inputs
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7. MEMS sensors for navigation support
Today’s Smartphone capabilities
 Accelerometers are already standard in
smart-phones: no additional component cost. Ready for basic
pedestrian
 Geomagnetic sensors will reach an adoption application
rate ~ 80% in smart-phones by end of 2010. today !!!
 Low cost, high resolution barometric pressure Indoor navigation
sensors are already available today… is feasible…
The lack of comprehensive SW solutions and indoor map availability
are today’s main inhibitors
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8. MEMS sensors for navigation support
Component cost: enabler or inhibitor ?
 Accelerometer cost drivers:
 Volumes are driving prices down. Strong price erosion experienced
in 2008 & 2009.
 Current smart phone accelerometer adoption rate is already
100 % and overall mobile phone adoption rate is expected to
be ~ 45% in 2010 – strongest growth already took place.
 What made this steep cost reduction possible ?
2005
Today !!!
5 x 5 mm 4 x 4 mm 3 x 3 mm 2 x 2 mm
Bosch Sensortec
8 Confidential | Marketing | 5/25/2010 | © Bosch Sensortec GmbH 2010. All rights reserved, also regarding any disposal, exploitation,
reproduction, editing, distribution, as well as in the event of applications for industrial property rights.