Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




264 posts

Ultimate Geek


#113319 13-Jan-2013 20:02
Send private message

A few newer phones like my Nexus 4 have a barometer to measure air pressure. Apparently this is used by the phone’s GPS system to determine your altitude to get a faster GPS lock.

I have seen a few apps that do something interesting with this data, one of these is pressureNET which crowd sources the data and displays it on a map (screenshot below). You can also get your own devices trend over time.


Anyone else find an interesting use for the barometer?

Create new topic
BDFL - Memuneh
67149 posts

Uber Geek

Administrator
Trusted
Geekzone
Lifetime subscriber

  #744197 13-Jan-2013 20:25
Send private message

Interesting... Using a barometer to represent altitude? These measure atmospheric pressure, and this varies depending on conditions, even on same altitude. Not sure this can help GPS that much. AGPS helps with a coarse location and from there it is easier for the GPS to know where to "look for" signals in the sky. Once there are enough signals then the GPS can have a fine location and altitude.

From the link: "The primary purpose of the barometer is (at least, I've been told)..." sounds more like "a friend of a friend told me" than first hand technical knowledge.







264 posts

Ultimate Geek


  #744211 13-Jan-2013 20:39
Send private message

Well Dan Morrill (the author of the post) is an android engineer working Google so I assume that he got good advice!

But yes my thoughts were the same as yours regarding weather conditions affecting the barometer, perhaps it is just "good enough" for the job, if a bit inaccurate.

 
 
 
 


2120 posts

Uber Geek


  #744214 13-Jan-2013 20:43
Send private message

freitasm: Interesting... Using a barometer to represent altitude? These measure atmospheric pressure, and this varies depending on conditions, even on same altitude. Not sure this can help GPS that much. AGPS helps with a coarse location and from there it is easier for the GPS to know where to "look for" signals in the sky. Once there are enough signals then the GPS can have a fine location and altitude.

From the link: "The primary purpose of the barometer is (at least, I've been told)..." sounds more like "a friend of a friend told me" than first hand technical knowledge.



The Barometer provides course altitude information to the GPS, a little like the a-GPS gives course 2D data.

Source

mjb

923 posts

Ultimate Geek

Trusted

  #744220 13-Jan-2013 20:50
Send private message

freitasm: Interesting... Using a barometer to represent altitude? These measure atmospheric pressure, and this varies depending on conditions, even on same altitude. Not sure this can help GPS that much.


Barometers are the primary method of determining altitude in a lot of electronic devices.. including dedicated GPS receivers. Also prominent here are altimeters for hobby rocketry.




contentsofsignaturemaysettleduringshipping


BDFL - Memuneh
67149 posts

Uber Geek

Administrator
Trusted
Geekzone
Lifetime subscriber

  #744294 13-Jan-2013 22:15
Send private message

They can be used for altitude sure, but they aren't absolute as the pressure varies with weather conditions. That's all.





1923 posts

Uber Geek


  #744301 13-Jan-2013 22:42
Send private message

Altitude (or the 'Z' vector ) is the least accurate component of a GPS fix.
But I can see how Google would use it to assist to a fix. It's likely they use reference information from local sources, which would be used to get a local offset over a larger area, that way the device barometer would provide users with a faster first fix and Google would/could improve their maps for 3D and collect a more accurate reference geoid....

Ham

462 posts

Ultimate Geek


  #744558 14-Jan-2013 14:31
Send private message

freitasm: They can be used for altitude sure, but they aren't absolute as the pressure varies with weather conditions. That's all.



Remember that Google will know the mean sea level pressure for anywhere in the world so would be able to use that as a reference for altitude...

Create new topic



Twitter and LinkedIn »



Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

OPPO Find X2 Lite brings flagship features to mid-range 5G smartphone
Posted 29-May-2020 12:52


Sony introduces the digital camera ZV-1 for content creators
Posted 27-May-2020 12:47


Samsung Announces 2020 QLED TV Range
Posted 20-May-2020 16:29


D-Link A/NZ launches AI-Powered body temperature measuring system
Posted 20-May-2020 16:22


NortonLifeLock Online Banking Protection now available for New Zealand banks
Posted 20-May-2020 16:14


SD Express delivers new gigabyte speeds for SD memory cards
Posted 20-May-2020 15:00


D-Link A/NZ launches Nuclias cloud managed network solution hosted in Australia
Posted 11-May-2020 17:53


Logitech introduces new video streaming solution for home studios
Posted 11-May-2020 17:48


Next generation Volvo cars to be powered by Luminar LiDAR technology
Posted 7-May-2020 13:56


D-Link A/NZ launches Wi-Fi Certified EasyMesh system
Posted 7-May-2020 13:51


Spark teams up with Microsoft to bring Xbox All Access to New Zealand
Posted 7-May-2020 13:01


Microsoft plans to establish its first datacenter region in New Zealand
Posted 6-May-2020 11:35


Genesis School-gen has joined forces with Mind Lab Kids
Posted 1-May-2020 12:53


Malwarebytes expands into privacy with fast, frictionless VPN
Posted 30-Apr-2020 16:06


Kordia to donate TV airtime on Channel 200 to community groups
Posted 30-Apr-2020 16:00



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.