When the Galaxy Nexus was first announced by Samsung at AsiaD in Hong Kong, they kind of glossed over the fact there’s a Barometer inside the device. Because they didn’t tell people why it was in there, we all just assumed it was there for the lulz or for developers to make interesting applications wrong. It turns out we were only part right. The Barometer can indeed be used by developers for weather-related applications and what-not, but its main purpose is to help the GPS get a location fix in a shorter amount of time.
As Dan Morril explains, to get a GPS location fix you need to solve a 4-dimensional set of linear equations: latitude, longitude, altitude and time (fun!). If you have a rough estimate of where you are, usually through aGPS, GPS performs less equations and can pick up your location quicker. However, to get a leg up on the equation for altitude, the Galaxy Nexus uses the estimated altitude from the Barometer to help the GPS perform even less equations to get your location resulting in a quicker accurate location fix. Impressive.
From being an ex GPS/GNSS sales person.. RTK and proffessional GPS all have a barometer in them and thats for one reason.. accurite height smoothing.. uncorrected GPS height is typicaly accurite to around 10-15 meters where 2D or XY is typicaly accurite to around 5 meters.. So when one satelites are dropped from the solution(aka Position) the heights can jump out… but if a baromiter stays steady at this change it will use some smarts to even the heights out.. its a shape the iPhone got the jump on GLONASS.. hopefully there will be some mainstream androids with this soon…… Read more »
The Xoom had a barometer too. It seems to be a requirement for a ‘Google Experience’ device these days.
I wonder if it is accurate enough to have any other use? And whether it has an API that devs can tap into. Could be lots of fun.
Indeed it did. Perhaps they were testing to see if it did help with GPS fix times.
The Barometer can be accessed via APIs. Apps like this have beeing using it in the XOOM: https://market.android.com/details?id=com.guildsoftware.barometer
Crowd sourcing barometer readings for weather predicting maybe?