#73 Graphical Glitch Plotting Footprints near pole

1.4
closed
nobody
Algorithm (5)
fixed
5
2013-12-02
2011-11-13
Charles Suprin
No

When satellites are near the pole, they occasionally develop a glitch in the footprint. The attached picture illustrates this behaviour.The glitch is a spike from near the lowest (magnitude) latitude point towards the pole.

This appears to occur from two different tests being applied for determining if the satellite coverage extends over the pole. The first is the test beta>pio2-ssplat. The second appears when pole_is_covered. When these disagree, odd artifacts can occur.

An initial replacement of the the test beta>pio2-ssplat with pole is covered yielded artifacts.

This testing occured with the AO-51 tle with the epoch 2011 November 13 03:28:31.

Discussion

  • Charles Suprin
    Charles Suprin
    2011-11-21

    SVN 955 fixes this bug. For the tle and time noted in the original bug, the spike is gone.

    There are now functions for testing if the satellite covers each pole and those functions are used in the pole_is_covered function so the answers should be consistent. These functions use the qrb measurement approach rather than angular sum and compare.

     
  • Charles Suprin
    Charles Suprin
    2011-11-21

    • status: open --> open-fixed
     
    • Milestone: SVN --> v1.4
     
    • Status: open-fixed --> fixed
     
    • status: fixed --> closed
    • resolution: --> fixed