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Position on the Map

I noticed a strange behaviour on the KiwiSDR Map. There is another KiwiSDR within a kilometer or so from my location since I received my KiwiSDR yesterday, they share the same Maidenhead locator: JO32gu. The positions of those two SDR's on the KiwiSDR Map are jumping back and forth or are changing position a few times per hour.

Sometimes the locations are way off, maybe 10 or 15 km. Wat could be the cause of this? I tried changing my locator to JO32fu, but that doesn't seem to help.

Any insights would be appreciated!

73, Albert PA3GUK

Comments

  • There is also a location field with coordinates, have you tried changing that?


  • This map simply works like that, it is a deliberate setting so that in the case of a high density of receivers in one location, not one pin is visible, but all of them, hence the spread of up to 20 km

  • edited February 18

    @HB9TMC Thanks for your reply, yes I tried that, doesn't make a difference. Both locator and coordinates are the same in both tabs, (Webpage and Public tabs)

    @ArturPL Thanks, I didn't know that! So I probably will have to live with it...

    73, Albert

  • Which map? map.kiwisdr.com? Locations on the public maps are dithered to protect the privacy of the Kiwi owner.

    The map on the admin GPS tab should be mostly accurate. But it can vary depending on how much of the sky is visible and how the sats are distributed across the sky. See: https://en.wikipedia.org/wiki/Dilution_of_precision_(navigation)

  • edited February 19

    @jks Thanks for your reply. Yes, this happens on map.kiwisdr.com

    My GPS has a very limited field of view, so that might explain it. I will improve that.

    In the GPS tab the location is fairly accurate.

    Do the actual GPS coordinates take precedence over the coordinates and locator in the Website and Public tabs?

    73, Albert

  • No. The high-resolution coordinates computed by the GPS are not leaked outside of the admin interface.

    Even when you use the "set from GPS" button on the admin public tab only two significant digits of the actual GPS location are set in the field.

    Not leaked to kiwirecorder either or any part of the user-mode API. Now the timestamps in the audio stream are very precise. For the purposes of TDoA etc. But this tells you nothing about the location.

  • Thanks. So the GPS doesn't explain the jumping pin on the map...

    This are my settings:


  • jksjks
    edited February 19

    The guy who runs the website linked to by map.kiwisdr.com does his own additional dithering and stuff I don't know about. I have no control over this. If this is what you are talking about.

  • edited February 19

    The coordinates in "Public" should be used for the receiver map, via the /status page, correct?

  • He starts with a subset of the /status information, which is embedded as comments in the rx.kiwisdr.com HTML. What he does exactly after that I don't know.

  • The pins on http://rx.linkfanel.net/ move around when you refresh the browser.

    Apart from randomisation, I think it is to ensure that all the pins are at least visible at some point in time, and not masked by others.


    Note, that none of these positions are actually correct, the closest one is the lower of the three in the last slice.


    Regards,

    Martin

  • Thanks for all the information, now I know it's normal behaviour.

    73, Albert

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