Oct 20 AT 5:54 PM Edgar Cervantes 25 Comments

What is that Galaxy Nexus barometer exactly for?


Most tech enthusiasts raised an eyebrow upon finding out that the recently announced Samsung Galaxy Nexus would have a barometer. Measuring your altitude can be helpful for many reasons, but to the end consumer, it will most times be irrelevant. So what is that thing doing in our next device?

Dan Morrill (Android engineer) has taken the time to explain what that feature is doing in a device like the Galaxy Nexus. According to Dan’s Google+ post, the barometer’s main purpose is to help the GPS lock on faster. In order to recognize your exact location, GPS systems need to determine your state in 4 dimensions (3 dimensions, plus time). Aside from time, GPS satellites need to identify your lattitude, longitude, and your altitude.

Android devices are already aided by aGPS (assisted GPS), which gets your approximate location from towers, connected networks, etc. After having those approximate location (longitude and latitude), it is much faster to find the exact location of your smartphone. Current phones would then take longer to lock on, because there is no efficient way of determining your altitude. This is where the barometer comes in to the rescue.

With the help of aGPS for determining latitude and longitude, and the barometer’s ability to determine altitude, GPS lock-on should be significantly faster.

Morrill goes on to mention that this method is also implemented in the Motorola Xoom, and is not really a new feature. It just didn’t receive the honors that it did with the Galaxy Nexus. It can also be used for other purposes like measuring pressure, but the before-mentioned was the reason why it was added.

There you go, guys! Now we all know what is up with this Galaxy Nexus barometer, and we can all move on to drool over its many other features and specs. Do you guys think that current devices take too long to lock on to GPS? If you own a Xoom, let us know if you see a significant difference.

Via: Engadget

Source: Dan Morrill (Google+)

Hello, I am Edgar Cervantes. I am an avid Android fan, and keeping myself updated on the topic is part of my daily life. I will always work hard to give the best of me to our community of Android enthusiasts, and I am very honored to be part of this ship. Hopefully we can all enjoy sharing our knowledge and opinions!

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  • http://Website Triangle

    I would like to know if enhanced GPS with the Russian GLONASS satellites are supported. Doesn’t sound like it will be.

    I guess the barometer will help.

  • CTown

    “Android devices are already aided by aGPS (assisted GPS), which gets your approximate location from towers, connected networks, etc.”

    Does AGPS require Data or just having service?

    • http://daniel.friesen.name dantman

      I believe aGPS is based on measuring the signal strength of known towers so I would say it’s probably just service.

    • Ann Monis

      It helps to have data on, so you get a better lock on your location. If you have the data off, you will be like 1-2 km off of your actual location.

    • Patrick O’Leary

      The assistance comes in two forms: coarse location (in four dimensions), and the ability to download the almanac and ephemerides from the internet, rather than from the GPS system. Coarse time just requires service. You should also be able to pick up coarse position from the network. However, neither of these are helpful unless you can use them to figure out which GPS satellites should be overhead. That requires at least an almanac; a good solution on top of that requires ephemerides, which provide detailed information about satellite orbits. Getting both the almanac and ephemerides (XTRA data) via aGPS requires a data connection. Since GPS satellites have very little bandwidth, downloading ephemerides directly from the satellites takes a couple of minutes of uninterrupted visibility.

      I’m just waiting for cell phones to become WAAS compatible. Or for all of CORS to go real-time. Or my cell phone to pick up L1/L2 carrier phase. Mmm, delicious precision.

  • Christopher Campbell

    I think certain devices do, I am not sure why newer HTC devices seem quicker than other manufacturers such as LG or Samsung. I hope the Galaxy Nexus’ GPS is as fast or faster than HTC’s implementation.

  • http://None CaribGrackle

    Cool to know, I hope they can work on something else to do with it over time.

  • asdf

    The fourth dimension is not time. A cube cannot exist in flatland; merely a projection would appear. A square cannot appear in 1D, a line would appear, so if the 4th dimension is time, and we’re only experiencing a 3d projection, what is time, really?

    • Aerohix

      1D is a line, a system along the x axis
      2D can represent images with two coordinates, such as a square or a circle in case both represent a distance (x,y), if you have one coordinate representing time you will get a moving point for each pair of (x,t), to represent this systems we use animations because that’s the way we can see time changing.
      3D can represent

      • Aerohix

        Im on my phone, posted the wrong thing, can you delete this plz?

    • rasterX

      A dimension can be any measure used to describe a state. In this case, calling time a dimension is applicable. You may be confusing the 3 spatial dimensions which exist in the universe we occupy versus a 4th spatial dimension, which does not exist, or at least we are unable to perceive it. Yes, I read Abbott’s book too, many years ago ;-)

    • Aerohix

      Let me see if i can make you understand:
      Imagine 1D as a static point, a system along the x axis that doesn’t have another coordinate to relate with.
      Now imagine a 2D system, one system capable of representing points with two coordinates (x,y), if you have one coordinate representing time (x,t) you will get a moving point for each pair of (x,t) values, it moves because to represent this systems we use animations because that’s the way we can see time changing.
      So we say 4D adds time because now you have a (x,y,z,t) system, to represent the 3D we draw it in a cubish style using distance, and to represent the 4th coordinate we usually use time.
      And in this case this is really what you have, a 4 coordinated system which represent (latitude,longitude,altitude,time(taken from your current speed))
      Hope this helps

    • Caz

      Time and space are different. We live in a universe with 3 spacial dimensions and one time dimension.

  • Rashad

    Augmented reality apps may also benefit from this kind of positional data, so that’s cool.

    We can also go ahead and file this feature under the category of “Your iPhone can’t do this!”


    My xoom connects slightly faster than my sensation.. I actually look at the barometer on the accuweather app.. Fun to see it drop as a storm is getting closer

  • Nathan

    OK but now release it so we can have it.

  • Dan sharp

    A barometer is used to measure atmospheric pressure. It’s an altimeter that measures elevation. Which has the nexus got?

    • tetracycloide

      Most altimeters are barometric altimeters that use a formula to derive altitude from pressure. Aircraft, for example, use barometric altimeters. So every barometer can be an altimeter as well because altitude can be derived from pressure.

    • Chris Cannon

      See this web page. It explains the relationship between air pressure and altitude: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/prs/hght.rxml

      Then this one to explain how an altimeter uses barometric pressure to calculate height.

      Ergo, an altimeter is simply a barometer made for a specific purpose

  • dang1

    I just hope this Samsung’s GPS is good. The GPS on alot of Samsungs that I’ve come across have trouble locking on to GPS signal.

    • BiGMERF

      when i tried it on the Tmo sgs2, it tracked quick and accurately

  • http://www.hackingvideos.net/ aakash1

    android rocks \m/

  • awesome3

    Unless the barometer is much more accurate than I believe it would be, then I don’t think I see why this would be all that helpful. If agps can get an approximate lock on your 2 dimensional position then from that you have a pretty good idea of elevation. I mean here in Indiana I know I’m not a mile above sea level and in Denver I know I’m not at sea level. Elevation maps could be sourced for this data and give a pretty good estimate of elevation. On the off chance you happen to be flying and using your phones gps then it may take a bit longer to get a lock but is that rare occurrence really worth adding a barometer? Weather would seem to throw this elevation off anyway with changes in the pressure as fronts move in. I’m thinking maybe they have something more planned for this beyond just faster gps lock to justify including it.

  • http://klout.com/#/SliestDragon SliestDragon

    Very cool idea. Would have never thought of that. Cool. :)

  • PhilElms

    It would be interesting if air pressure could be crowd sourced from phones to supply potentially millions of extra data points for weather forecasting…