Barometric pressure sensors are being integrated into premium and mainstream smartphones, as well as wearables and Internet of Things (IoT) devices, to measure air pressure. These sensors have a number of uses, including providing accurate altitude information.

Key applications of barometric pressure sensors include:

* Indoor Navigation: Because GPS signals are often blocked inside buildings, pressure sensors can be combined with accelerometers to create a three-dimensional navigation matrix. This technology can help people navigate shopping malls and underground parking garages. It is also essential for emergency services to accurately identify a 911 caller's location inside a large building, and the FCC has updated its E911 rules to mandate that a caller's indoor location be automatically transmitted to first responders.

* GPS Enhancement: Barometric pressure sensors can enhance GPS accuracy in outdoor settings where obstacles like trees or skyscrapers, bad weather, or an inadequate number of satellites might compromise the signal. The sensor's altitude data can be used to compensate for GPS positioning errors by comparing it with known terrain elevations from a database.

* Fitness and Calorie Tracking: Pressure sensors improve the accuracy of fitness trackers, especially for calorie counting. While an accelerometer can detect that a person is using stairs, it cannot determine whether they are going up or down; a pressure sensor, however, can establish the direction of vertical movement, which allows calorie-tracking software to correctly calculate energy expenditure. Tests have shown that when used with accelerometers, air pressure sensors can boost the accuracy of calorie tracking by 10 to 15 percent.

* Weather Forecasting: Air pressure is a key component of weather forecasting. Weather applications, such as Dark Sky, Sunshine, and Weather Signal, have started using crowdsourced air pressure readings from iPhones and Android devices to improve the accuracy of their predictions.