Implementing excellent indoor navigation capabilities for mobile and wearable products
Application of fitness tracking/mapping and indoor navigation apps using high-precision pedestrian dead reckoning technology

STMicroelectronics’ latest digital compass (eCompass) can enhance navigation and exercise mapping capabilities for smartphones, smartwatches, fitness trackers, and other wearable devices even when satellite navigation is not available.

Smartphone fitness tracking apps, smartwatches, and smart bands continuously require location data for mapping and record measurement. Furthermore, users who wish to improve their records or share their results online place great importance on accuracy. A built-in digital compass helps calculate location when running or cycling under trees or inside buildings—in other words, when satellite signals are unavailable. Solutions available to date show a potential error of approximately 10 degrees in regions with latitudes such as northern Italy or northern California, which means a user could deviate from the normal course by more than 150 meters for every kilometer traveled.


However, ST’s digital compass device, the LSM303AGR, succeeded in reducing the azimuth error range to less than 4 degrees by applying its proprietary high-precision geomagnetic sensor manufacturing technology. When combining ultra-low power operation characteristics, which consume up to 50% less power than other competing devices of the same type in low-power mode, with such improved accuracy, it can be said to be more suitable for high-precision Pedestrian Dead Reckoning (PDR) functions of mobile devices.

Minimizing space usage and power consumption through the integration of high-performance MEMS accelerometer sensors

Meanwhile, while competing products can experience rapid temperature fluctuations of up to 35% due to even minute differences between room temperature and body temperature, the LSM303AGR maintains accuracy across the entire temperature range of -40°C to 85°C and improves the accuracy of dead reckoning in applications such as automotive navigation.

Andrea Onetti, Group Vice President and General Manager of MEMS Sensors at ST, stated, “The industry-leading technology applied to ST’s new digital compass device will further solidify ST’s leading position in location tracking and motion detection in the consumer sector,” adding, “As predicted by IHS, the production volume of devices such as smartphones and smartwatches equipped with apps like fitness trackers and personal navigation will exceed 100 million units by 2020[1], and the high-precision PDR capabilities implemented in this device will further enhance the user experience.”

ST's new digital compass, the LSM303AGR, is currently available for purchase. It measures 2 x 2 x 1mm, features 12 pins, and comes in an LGA package. It is available for purchase at $1.49 for orders of 1,000 units.