Announcement

Collapse
No announcement yet.

Selection of Radar sites for web display?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Selection of Radar sites for web display?

    Does anyone know what are the criteria based on which the planes are associated with radar sites on the web page?
    For example, my radar site picks up a plane that took of from an airport close-by. I look on FR24 live tracker and it's there, and down, where that radar dish is shown it says Radar "T-KPHF1" and shows my site. Good.
    The plane flies away, I can still see it on my local web-page (ADS-B), but, at not even 5 miles from me, the "Radar" changes to F-KFKN1. Well, that's a station at least 30-40 miles away, and probably it just picked up that plane. Why was it switched from my feed?
    Why I ask this? Because most of the time, when I filter the Live tracker page I see zero planes as being associated to my radar. But I see multiple associated with other sites (mostly F-KFKN1, F-7NC21).

    My question is... why? Is something that makes my data un-trusty or un-reliable? Because then, I would like to fix that.

    Is that based on the maximum range? One of the sites doesn't share it's stats, the other indeed has a bigger range. I was imagining that the hand-over happens when I drop the signal, another radar is selected (from the many that are seeing that plane). Not that is preemptively switched at 10 miles out.

  • #2
    It's random (were told) based on all data sources at the time. And usually/often incorrect.

    Ignore it and move on.

    Short of removing it totally which will cause too much a stir. It's not acted upon nor accurate to look at and try and gauge how much you contribute
    Posts not to be taken as official support representation - Just a helpful uploader who tinkers

    Comment


    • #3
      Originally posted by Oblivian View Post
      It's random (were told) based on all data sources at the time. And usually/often incorrect.
      I can't... Things that don't make sense bother me. Those have consistently more planes shown. It's not random AFAIK.
      Thanks for interaction anyway 😀

      Comment


      • #4
        Having monitored it in the past, the tracking site display defies logic. Some other sites don't show the feed deliberately, it avoids the issue mentioned.

        Comment


        • #5
          Originally posted by Stealth View Post
          Having monitored it in the past, the tracking site display defies logic. Some other sites don't show the feed deliberately, it avoids the issue mentioned.
          I'd be happier if it just said 'MLAT' or 'User' or 'FR24'
          Posts not to be taken as official support representation - Just a helpful uploader who tinkers

          Comment


          • #6
            Originally posted by SoNic67 View Post
            I can't... Things that don't make sense bother me. Those have consistently more planes shown. It's not random AFAIK.
            Thanks for interaction anyway ��
            You have to understand how databases work to get a handle on what actually goes on at the server to get the stuff you see publicly displayable. And fast

            They don't get the same data from a single location and there is a lot of multi tiered data being generated as you go. Its a bit different to a local receiver with VirtualRadar server that grabs your data, and looks up the rest via internet links live.

            Hex - Aircraft (Altitude/position/squawk etc - user upload data)
            Registration - external database based on above
            Flight to/from - external database + 3rd party database after finding above
            Image - external site based on accumulated data from above

            Grab that.
            Calculate the most recent data from in some cases 30+ receivers getting the same data, with ever so slightly different time stamped packets based on distance and upload rate
            Offload some of the tasks to different geographical servers. And then centralise it again.
            Unpack it, combine it into a single table. Evaluate that table.

            Reformat it into a format the web page can display the data friendly. Then send it to the public facing server and plot it.

            Every, 4, seconds.

            In that sense. Working out who sent the most recent data and making sure its valid down to 1 person. Is very, very low priority.
            Posts not to be taken as official support representation - Just a helpful uploader who tinkers

            Comment


            • #7
              I can just add that altitude can be from feed 1, speed from feed 2, position from feed 3 and callsign from feed 4. And up to 150 feeders can see the same aircraft at crusing altitude in crowded locations like Germany, Netherlands or UK. To reduce the bandwidth for us and feeders we just ask some (maybe 5-10) of these 150 feeders to upload data for this aircraft. So 140-145 additional feeders see the aircraft but don't upload it. The radar-id should have been removed long time ago, but we keep it just to keep some users that like it satisfied.

              More feeders improve MLAT, reduce the risk for errors and improve low level coverage. Up to 150 feeders can see the same aircraft at 35,000 feet, but a Piper at 1,500 feet is probably only detected by 1-4 feeders.

              Comment


              • #8
                Originally posted by Mike View Post
                I can just add that altitude can be from feed 1, speed from feed 2, position from feed 3 and callsign from feed 4. And up to 150 feeders can see the same aircraft at crusing altitude in crowded locations like Germany, Netherlands or UK. To reduce the bandwidth for us and feeders we just ask some (maybe 5-10) of these 150 feeders to upload data for this aircraft. So 140-145 additional feeders see the aircraft but don't upload it. The radar-id should have been removed long time ago, but we keep it just to keep some users that like it satisfied.

                More feeders improve MLAT, reduce the risk for errors and improve low level coverage. Up to 150 feeders can see the same aircraft at 35,000 feet, but a Piper at 1,500 feet is probably only detected by 1-4 feeders.
                How do you differentiate between the airliners/high level cruisers in a crowded area and a Piper Cub at 1500 ft? What happens to the Piper Cub if it's not in range of the chosen 5-10 uploaders? Tough luck?

                Comment


                • #9
                  We don't differentiate anything, the system just limit how much data it wants.
                  So a feeder 1 can upload aircraft 1,2,3,4 but not 5,6,7,8,9
                  and feeder 2 can upload aircraft 3,4,5 but not 1,2,6,7,8,9
                  feeder 3 can upload aircraft 1,8 but not 2,3,4,5,6,7,9

                  Comment


                  • #10
                    So if the Piper Cub is nicely being MLAT'd at 1500ft by feeders #11 to #150 but not in receiver range of feeders #1 to #10 (the only ones you accept data uploads from) then despite the Piper Cub's exact location being known, you don't show it on the map?

                    Comment


                    • #11
                      Seems to be highly accurate for my area. One station north of me picks up aircraft inbound to me from that direction and from the south a selection of ~6 picks up those aircraft.
                      I only pick up some high level inbound from the west and all low level aircraft near me. I know that the net benefit I provide is low level coverage within 150km of CYAZ.

                      Comment


                      • #12
                        Originally posted by rik130 View Post
                        So if the Piper Cub is nicely being MLAT'd at 1500ft by feeders #11 to #150 but not in receiver range of feeders #1 to #10 (the only ones you accept data uploads from) then despite the Piper Cub's exact location being known, you don't show it on the map?
                        How the h*ll did you come to that conclusion? Of course not.
                        /M
                        F-ESDF1, F-ESGG1, F-ESGP1, F-ESNK1, F-ESNV2, F-ESNV3 F-ESSL4, F-LFMN3
                        P-ESGR, P-ESIA, P-ESIB, P-ESGF
                        mrmac (a) fastest.cc

                        Comment


                        • #13
                          Originally posted by MrMac View Post
                          How the h*ll did you come to that conclusion? Of course not.
                          I think we have to bear in mind that newcomers don't read all the previous posts and have genuine interest in understanding how things work, even if the explanations don't always appear logical.

                          The attributed radar "label" has been a growing issue from the very beginning, even when there were very few FR24 feeders. With hindsight, I'm sure FR24 would have removed it years ago. But, as they say, "we are where we are".

                          Unless it has a reason to block or partially display a tracked flight, it's in FR24's business interests to display as many flights as possible. I am more than happy to let it deploy the most efficient method it can devise. As for the radar label, as others have suggested, we should move on. It's now totally meaningless, even displaying T-MLAT1 for aircraft using ADS-B.

                          https://forum.flightradar24.com/thre...742#post109742
                          Mike


                          www.radarspotting.com

                          Radarspotting since 2005

                          Comment


                          • #14
                            Originally posted by rik130 View Post
                            So if the Piper Cub is nicely being MLAT'd at 1500ft by feeders #11 to #150 but not in receiver range of feeders #1 to #10 (the only ones you accept data uploads from) then despite the Piper Cub's exact location being known, you don't show it on the map?
                            MLAT and ADS-B is handled completely separately. The discussion here is about ADS-B radar codes. When a position for a MLAT aircraft can be calculated it's always done and the aircraft is shown with MLAT radar code.

                            Comment


                            • #15
                              Originally posted by MrMac View Post
                              How the h*ll did you come to that conclusion? Of course not.
                              /M
                              It was pretty simple : Mike said that out of 150 feeders in a highly populated area, 140 to 145 of them are ignored, so it was a perfectly valid question what happens to the Piper at 1500ft down in a valley, for example, if those 5-10 feeders are all located on the other side of the hill and can't "see" it because of the terrain.

                              Comment

                              Working...
                              X