Plot GPS data with GPS time of week and UTC time on the x-axis

Discussion in 'General GPS' started by Glenn MacGougan, Dec 29, 2007.

  1. I've put together an open source app, plot2d (http://
    plot2d.sourceforge.net), for plotting data (from ASCII files, almost
    any delimiter) directly to a compressed image. It uses a simple ASCII
    options file. It can also generate statistics for each series.

    The program lets you plot GPS time of week and UTC time on the x-axis.

    An example data file with GPS time of week as a column can be
    downloaded here:
    https://plot2d.svn.sourceforge.net/svnroot/plot2d/trunk/examples/gps/PositionError.txt
    The first column is GPS time of week followed by error_N (m) error_E
    (m) error_UP (m) error_2D (m) error_3D (m).

    The project is still in the Alpha development stage. I'm looking for
    further design feedback on the software.

    What do you think of the target application? Batch/script files for
    generating plots+statistics directly to compressed bitmaps.

    Would you use this application and why/why not?

    What is lacking in the documentation?

    If you're keen, some review of the source is always appreciated.
     
    Glenn MacGougan, Dec 29, 2007
    #1
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  2. Glenn MacGougan

    Darius Guest

    Hi,
    just give more examples as what I see is Voltage plot not GPS data.
    My friend sdaid that since release of Googvle Earth, Google Maps there
    is a little chance to develop any
    commercial gps data visualization application.
    You can convert your csv file to xml, than to kml and get data
    visualized in GE or GM.
    Look at Xtraceroute
    http://www.dtek.chalmers.se/~d3august/xt/index.html

    Darius
    Finite State Machines
    Indoor Navigation/ Surveillance / Identification Systems
    LBS (location-based services) Navteq developer
     
    Darius, Dec 29, 2007
    #2
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  3. The options file just needs to be configured a bit further. Check out
    the GPS example in
    https://plot2d.svn.sourceforge.net/svnroot/plot2d/trunk/examples/

    The example image is:
    https://plot2d.svn.sourceforge.net/svnroot/plot2d/trunk/examples/gps/PositionError.bmp

    I agree for plotting the actual GPS data but this software is useful
    for doing some numerical analysis.
    The example I gave shows the errors with an RTK GPS solution over time.
     
    Glenn MacGougan, Dec 29, 2007
    #3
  4. Glenn MacGougan

    Darius Guest

    Thanks.
    Please let me know what is a nature of position error at 18:50 ?
    Does it work for any geoposition ?

    Darius
     
    Darius, Dec 29, 2007
    #4
  5. The position error is outside the window at 18:50 (refer the max/min).
    Try changing the ylimits to see the rest of the data.

    The position error is calculated with respect to a known reference
    position in this case. The math for it can be found at
    http://gnsstk.sourceforge.net/geodesy_8h.html#b664109cc9edd99427ec9c141a42b6d9

    Position errors can be calculated with respect to known trajectories
    as well, so yes it can work for any geoposition if you have a
    reference solution of higher order magnitude (say from a GPS/INS
    system).
     
    Glenn MacGougan, Dec 29, 2007
    #5
  6. Glenn MacGougan

    Darius Guest

    Thanks.
    I just watched bitmap file so no chance for menu access
    from https://plot2d.svn.sourceforge.net/svnroot/plot2d/trunk/examples/gps/PositionError.bmp
    Is your error correction algorithm already implemented into Sirf III
    gps receivers ?
    It would be nice to have 3D Earth visualization for a standard Sirf
    III gps receiver vs. one running your error correction algorithm to
    see regions most affected by error.

    Darius
     
    Darius, Dec 30, 2007
    #6
  7. It's not error correction unless the true path or location is known -
    meaning it has to be surveyed already.
    Sirf III is likely to use position correction and assistance from WiFi
    in the near future though.
     
    Glenn MacGougan, Dec 30, 2007
    #7
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