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Bad receiver 'handover' - Loss of tracking

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  • Bad receiver 'handover' - Loss of tracking

    I have noticed that there is a problem for FR24 when one chosen receiver looses contact and another receiver has to take over.

    As an example SK1245 landes at Aarhus (AAR) and T-EKAH7 follows it all the way on approach to landing and then to parking at stand no. 2.


    SK1245 T-EKAH7 track.jpg

    If however any other receiver is used on approach then they will loose contact before landing. Now T-EKAH7 should be able to take over, but that doesn't happen. The aircraft is not tracked after landing.

    It seems as if FR24 takes too long to recognize the loss of contact. For aircraft in the cruise at high altitude this is seldom noticeable as FR24 continue to draw a track and will eventually 'give up' on the chosen receiver and switch to a better option.

  • #2
    I've been trying to understand how FR24 manages the feeder handover when a distant feeder loses contact and other local feeders are available and tracking the same aircraft. Kpin (above) and JT2 in post82659 back in 2016 both raised this and didn't get any replies.

    I know such handovers do happen at altitude while enroute - but there are a reasonable number where it doesn't when aircraft are at low altitudes on landing approach and tracked aircraft 'disappear' due to the long time gap between a loss of signal and re-acquisition by another feeder. Does anyone know the methodology or process behind this ?

    ylis

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    • #3
      There is no handover. All receivers are feeding data into the same database. One feeder can be providing the position and another one the altitude. The merged data is sent to the map with a random feeder code.

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      • #4
        I'm still regularly seeing this behaviour - maybe handover was the wrong term to use. When an aircraft goes out of range of a feeder, it just 'hangs' there even though other local feeders are tracking it. Sometimes after a period of time, the tracking might pick up and continue and display the more local feeder ID - and there are times when this doesn't happen. Based on previous advice that all feeders contribute to the database and a random feeder ID is assigned to the track, this minute or two break doesn't seem logical - unless the refresh rate or similar is very slow. Sorry but not sure how to explain this any clearer. Any one able to elaborate ?

        ylis

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        • #5
          Originally posted by ylis View Post
          I'm still regularly seeing this behaviour - maybe handover was the wrong term to use. When an aircraft goes out of range of a feeder, it just 'hangs' there even though other local feeders are tracking it. Sometimes after a period of time, the tracking might pick up and continue and display the more local feeder ID - and there are times when this doesn't happen. Based on previous advice that all feeders contribute to the database and a random feeder ID is assigned to the track, this minute or two break doesn't seem logical - unless the refresh rate or similar is very slow. Sorry but not sure how to explain this any clearer. Any one able to elaborate ?
          I fully understand what you are saying. As I just added my first radar to FR24 that's something I've noticed too when checking my area.
          Planes approaching at my local airport being controled by a radar a bit far from it. As it loses contact with that radar due to the montains in the area I also see it takes a big while until another local radar kicks in and the plane gets replaced on the map.

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          • #6
            Originally posted by Mike View Post
            There is no handover. All receivers are feeding data into the same database. One feeder can be providing the position and another one the altitude. The merged data is sent to the map with a random feeder code.
            I'm aware this there is no 'handover'. However it is clearly so, that when one receiver loses contact, FR24 struggles to smoothly pick up with data from another receiver. And that is very apparent when aircraft are on the ground and making sharp turns on taxiways and aprons. In the cruise it is hardly ever noticed.

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            • #7
              Is there a setting that changes how often data is uploaded ? I'm wondering if this might be a cause. In my Data Sharing Stats, the upload rate always shows 0KB/s and the Last Upload can at times be 2 mins old. Increasing the upload frequency will obviously increase data usage ... but may also remove this gap in the 'non-existent' 'hand-over' lag time.

              ylis

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              • #8
                Originally posted by ylis View Post
                Is there a setting that changes how often data is uploaded ? I'm wondering if this might be a cause. In my Data Sharing Stats, the upload rate always shows 0KB/s and the Last Upload can at times be 2 mins old. Increasing the upload frequency will obviously increase data usage ... but may also remove this gap in the 'non-existent' 'hand-over' lag time.
                Nopes. And the upload rate is only valid on the real-time uploading platforms I think Maybe only the pi24 or their own boxes.

                Same with MAC and so on. Last upload seems to drop off when no traffic too (ping/keep alive)

                And I don't know if ground tracks will ever be that accurate. If the underside antenna is being used you'll need a heap of antennas in LoS for the adsb and the GPS accuracy rates mixed with a 5-7second upload gap.. it can take 3 turns toward next location beforen it's updated.
                Sent from my XT1092 using Tapatalk
                Last edited by Oblivian; 2018-07-26, 23:26.
                Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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