STMicroelectronics (ST) has launched an electronic compass (“eCompass”) that it claims reduces heading error in dead reckoning applications used when satellite navigation signals are unavailable.
STMicroelectronics' LSM303AGR electronic compass combines a three-axis magnetometer and a three-axis accelerometer on a single 2 mm x 2 mm x 1 mm chip. Image source: STMicroelectronics. Fitness-tracking smartphone applications, smartwatches and bands need continuous location data for mapping and recording, and accuracy is critical for wearers who like to monitor their progress and share achievements online. A built-in eCompass helps calculate location when inside buildings or when running or cycling under tree cover.
However, according to ST, current eCompass solutions can make errors of as much as 10° in latitudes such as Northern Italy or Northern California. Such heading errors can put a user off-course by 150 meters or more for every 1,000 meters traveled.
ST says its new LSM303AGR eCompass cuts the heading error to less than 4°. Citing the enhanced accuracy as well as power consumption up to 50% less than competing devices when in low-power mode, the company positions the new device as particularly well suited to high-precision pedestrian dead reckoning on mobile devices. It also enhances dead reckoning accuracy in applications such as automotive navigation, and maintains accuracy over the full temperature range from –40° C to 85° C.
The LSM303AGR combines a three-axis MEMS accelerometer and a three-axis anisotropic magneto-resistive (AMR) sensor that ST says delivers higher sensitivity and lower noise than conventional Hall sensors. ST also claims superior temperature stability for the device compared to alternatives based on giant magneto-resistive or tunneling magneto-resistive technology. The AMR sensor's high (±50 gauss) dynamic range further contributes to the device’s accuracy by preventing magnetic saturation in areas of high ambient-field strength.
ST’s LSM303AGR eCompass is available now, packaged as a 2 mm x 2 mm x 1 mm 12-lead land grid array, priced from $1.485 for orders of 1,000 pieces.
