Barometric Pressure Sensor for Smartphones, Wearable and Hearable Devices

Bosch Sensortec has announced a barometric pressure sensor that is able to deliver much higher levels of accuracy for altitude tracking in smartphones as well as wearable and hearable devices.

Barometric Pressure Sensor for Smartphones, Wearable and Hearable Devices

The sensor, the BMP390, can measure height changes below 10cms thanks to the improved resolution and is 50 percent more accurate than its predecessor.

Accurate altitude detection helps to localize people indoors, where GPS signals are not available. The addition of the vertical-specific position to existing horizontal information enables first responders to determine the floor level of smartphone users who trigger an emergency call.

“The use of Bosch Sensortec’s latest BMP390 pressure sensor in smartphones, enables a high precision localization service that ultimately has the potential to save thousands of lives,” said Dr. Stefan Finkbeiner, CEO at Bosch Sensortec.

Wireless providers in the US will soon be required to meet an increasingly stringent series of location accuracy benchmarks, including providing the caller’s dispatchable location and similar moves could be implemented in other regions like Europe or Asia, to further improve people’s safety and peace of mind.

Bosch and NextNav, a 3D geolocation service provider, have collaborated on component specifications and system performance resulting in consistent, high accuracy z-axis capabilities indoors. This is accomplished by applying barometric pressure sensors in the phone, like the Bosch BMP390, and combining them with NextNav’s Metropolitan Beacon System (MBS) z-axis service to determine three-dimensional location and positioning.

The sensor also enables improved indoor navigation in general, for example in combination with the Position Tracking Smart Sensor BHI160BP. These solutions compensate for traditional localization technologies such as GPS that do not work efficiently in shielded environments.

Furthermore, the BMP390 is able to support enhanced GPS applications for outdoor navigation and calorie expenditure estimation tasks. The use of advanced barometric pressure sensing can determine whether a user is walking up or down an incline, stairs or lifting weights during a fitness training session. This helps to increase the precision of calorie tracking by up to 15 percent. Thanks to the improved accuracy of altitude measurements, fitness trackers are able to show exactly how far a user has run, walked or cycled.

The BMP390 provides a typical relative accuracy of ±0.03 hPa. Typical absolute accuracy is ±0.5 hPa. The accuracy is the result of significant improvements in temperature stability, drift behaviour and noise. The sensor offers high temperature stability across its entire operating temperature and pressure range of 0 to 65 °C and 700 to 1100 hPa respectively, with an average temperature coefficient offset (TCO) of just ±0.6 Pa/K. Noise is also low, at only 0.9 Pa typical, an improvement of 25 percent relative to the predecessor BMP380. The device also provides high long-term stability, and low short- and long-term drift.

Measuring only 2.0 mm x 2.0 mm x 0.75 mm, the sensor is easy to integrate into portable devices. Power consumption is kept low at 3.2 μA at 1 Hz (typical) to maximize battery life on portable devices.

Source: Barometric Pressure Sensor for Smartphones, Wearable and Hearable Devices

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