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Old July 17th 14, 01:05 AM posted to uk.sci.weather
Tudor Hughes Tudor Hughes is offline
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Default Hidden barometer in mobile phone

On Tuesday, 15 July 2014 01:50:48 UTC+1, Alan LeHun wrote:
In article , says... If it is a barometric pressure sensor, which I doubt, then all well and good. Bosch bmp180 digital sensor usually on modern phones. Older phones generally used the bmp085. Bosch appear to have a near monopoly in this market. They are /surprisingly/ accurate being able to detect altitude changes of just a couple of cm. ANd yes, it's primary purpose is to fine tune the gps altitude readings.


How can it fine-tune the GPS height without a reference MSL pressure at the point and time of observation and where does it get that from? How accurate is the reference MSL pressure? Precision aneroids are fairly thin on the ground, at least in this part of the world.

Tudor Hughes, Warlingham, Surrey