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  • #16
    Hi Controller
    Is there any more information about this display problem? I still have the strange plane icon behaviour.

    Andrew

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    • #17
      Hello Andrew,

      Im sorry I do not have any other information. Normaly Mike answers these problems fast, it seems to bee more difficult.

      I took off my upload until problem is solved.

      Ralph

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      • #18
        Thanks Ralph. I guess we'll just have to wait a while. It's just annoying watching icons shooting around erratically!

        Andrew

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        • #19
          We will all have to be patient as Flightradar24 changes over to the new feeder software, there are bound to be some teething problems.

          It affects the Database updater's more than anyone as what we see on the map is not always reliable and sometimes i have to do Playback several times on different days to confirm that route is correct.

          Flightradar24 has improved massively since it first started and sometimes bugs do affect the Aircraft on the Map when changes are made.
          AMS Daily Fight Information: http://schiphol.dutchplanespotters.nl/

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          • #20
            Speedbird, many thanks for that. Nice to know it's not my PC playing up.

            Is there any indication, however crude, as to how long the changeover will take to complete? (A really annoying question, I know....)

            Andrew

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            • #21
              ADS-B - evaluation of transponder data

              I have carfully watched the problems of these wrongly indicating positions.

              Actually waht happens is - obviously this (new) software is doing "dead reckoning" on its targets for some seconds. This means, for a certain time frame the position of the aircraft is calculated by the speed and track / heading given by the ADS-B transponder.

              However - there is on little problem. As to the ADS-B specifications somea ircraft are equipped with "weight off wheel" switches. So landing, when the weight is on - or until take-off, when the weight goes off - some functions of the transponder can be disabled. This may differ from aircraft to aircraft - it is not even type specific. The aircraft watched - showing the symtoms reported - all showed their last speed prior touchdown and the tracks whilst taxiing. Ergo ....

              The position and speed are not coming from the same aircraft systam - and - it is not necessarily GPS tha supplies the position to the transponder. See FAR 91 and the respective TSO's.

              The software developers will only have two possibiliteis to solve this problem. Either turn off the "dead reckoning" function - or - include an algorythm in the sofware to calculate the mean speed between the last reported positions.

              By the way - the digital radar systems as used by ATC normaly use a similar sofware. Radar positions sometimes tend to "jump". The software calculates the postion on bases of dead reckoning and overlays with the measured last positions of the aircraft (mostly 4 to 8 - depending on the system). The different set up = multiradar, precision of the radar(s) used, flight altitudes - grade the different positions and show the most probable one on the dispays.

              A similar system is used for navigation. E.g. differential GPS uses the short term precision of a platform (INS) and the long term precision of a GPS to calculate and display a position. Why is GPS called precise only long term and nor short term- very simple - specificall when an aircraft is changing pitch and or attitude the signals from some Satellites may be shielded off. As pitch and bank are mainly used to perform departure and arrival - during approach - using GPS only - the GPS system alone is not qualified to perform precision approaches.

              Lets see how it is solved.

              Greetings

              Andreas

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