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  • Google to provide raw GPS measurements

    From jjt99@msn.com@21:1/5 to All on Fri Jul 15 18:59:55 2016
    An article in the July 2016 GPS World magazine states that raw GPS measurements will be available to apps in the Android N operating system, which will be released later this year. This means you can get pseudoranges, doppplers, and carrier phase from a
    phone or tablet!

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  • From Terje Mathisen@21:1/5 to jjt99@msn.com on Sat Jul 16 16:53:15 2016
    jjt99@msn.com wrote:
    An article in the July 2016 GPS World magazine states that raw GPS measurements will be available to apps in the Android N operating
    system, which will be released later this year. This means you can
    get pseudoranges, doppplers, and carrier phase from a phone or
    tablet!

    That is extremely interesting, it would seem to make it possible to use
    any pair of Android N devices as a base+rover setup for cm (or least sub-sub-meter) resolution measurements. (The lack of a proper antenna
    will probably be the real limiter.)

    With an app which stores all the raw data you should also be able to do post-processing with a single device plus some reference station data.

    Terje

    --
    - <Terje.Mathisen at tmsw.no>
    "almost all programming can be viewed as an exercise in caching"

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  • From Stichting ST@21:1/5 to All on Mon Jul 18 19:14:30 2016
    On Sat, 16 Jul 2016 16:53:15 +0200, Terje Mathisen <terje.mathisen@tmsw.no> wrote:

    jjt99@msn.com wrote:
    An article in the July 2016 GPS World magazine states that raw GPS
    measurements will be available to apps in the Android N operating
    system, which will be released later this year. This means you can
    get pseudoranges, doppplers, and carrier phase from a phone or
    tablet!

    That is extremely interesting, it would seem to make it possible to use
    any pair of Android N devices as a base+rover setup for cm (or least >sub-sub-meter) resolution measurements. (The lack of a proper antenna
    will probably be the real limiter.)

    With an app which stores all the raw data you should also be able to do >post-processing with a single device plus some reference station data.

    Terje

    Sure that is very nice if it becomes real.
    Many years ago I used an Garmin GPS12 (can output raw data) that with RINEX conversion gave me with postprocessing and an hour measurement a 95% position accuracy of 40 cm. (basestation placed 15 km distance)
    But remember: on a single wavelenth you do not know the ionosferic delay so cm accuracy can not be reached. The problem of the unknown positon of the faze-point of the antenna is secundair.

    Piet

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  • From Alan Browne@21:1/5 to jjt99@msn.com on Thu Jul 21 11:06:53 2016
    On 2016-07-15 21:59, jjt99@msn.com wrote:
    An article in the July 2016 GPS World magazine states that raw GPS measurements will be available to apps in the Android N operating
    system, which will be released later this year. This means you can
    get pseudoranges, doppplers, and carrier phase from a phone or
    tablet!

    Very neat. Apple bury even basic satellite data (which sats, PRN's,
    elevation, azimuth, etc.). I've been thinking of getting a good Android
    phone (used) in order to get that data.

    As others point out, if the data is exposed to the next levels down,
    some pretty good "poor man's" differential stations could be developed
    for at least sub meter accuracy - maybe dm level.

    Perhaps the antenna phase center can be determined experimentally?
    (Note that most smart phone antennas are very sub optimal wrt pattern in
    the first place). See http://www.antenna-theory.com/design/gps.php for
    one discussion which claims the antennas are not even circ-pol - what
    would that do to phase measurements (if anything).

    I'd also like a recorder that could go to about 5 Hz.


    --
    She hummed to herself because she was an unrivaled botcher of lyrics.
    -Nick (Gone Girl), Gillian Flynn.

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