duplicate planes on webpage

[Sam26K]

Hi,

I live in the San Francisco bay area and it seems that often the same plane is displayed twice by two different "radars". Attached is an example. There are better examples with planes on top of each other at the same altitude with exact speed and direction. Lately I see these kind of duplicates every time I load the website.

Is there anyway to tune out the false returns?
Another thing I've noticed is that data from different radars are often out of synch with each other on real time position. Two different planes landing at SFO at the same time is an example.

TIA.

[airnrail]

Hi,

I live in the San Francisco bay area and it seems that often the same plane is displayed twice by two different "radars". Attached is an example. There are better examples with planes on top of each other at the same altitude with exact speed and direction. Lately I see these kind of duplicates every time I load the website.

Is there anyway to tune out the false returns?
Another thing I've noticed is that data from different radars are often out of synch with each other on real time position. Two different planes landing at SFO at the same time is an example.

TIA.

The T-F5M track is based on FAA data and is 5 minutes delayed. It is not derived exclusively from radar and covers North America, the north Pacific and the north Atlantic. The T-MLAT2 track is generated from the signals of several Mode S receivers and processed mathmatically to work out the position of the plane. That you saw these probably means that the aircraft does not have an ADS-B transponder. ADS-B is the technology that FR24 mostly relies upon. You can switch off the FAA feed in Settings Visibility but it will probably stop you seeing a lot planes in your part of the world.

[Patrick Reeves]

In your example, altitude is only 2900 ft. M-LAT has problems at lower altitudes. Looks like it's toggling between the 2 (FAA and M-LAT)

[Sam26K]

Thanks for the replies but it doesn't help a lot. Turning off the FAA feed cuts out too much data. The nice thing about FR24 is all the data but sometimes duplicates are propagated. It would be nice to see this problem addressed at the front end server. One of the problems I see in the SFO area is there are a lot of feeders that don't all have equal info as to be easily recognized by the software as the same plane.

If you want to see what I mean, follow the flights departing from KSJC for awhile. A lot of them have ghost FAA flights that follow them delayed by the famous five minutes.
FR24 is a European website and I guess they don't have that problem as much in Europe. But it is annoying to everyone watching flights departing from the USA

[airnrail]

Thanks for the replies but it doesn't help a lot. Turning off the FAA feed cuts out too much data. The nice thing about FR24 is all the data but sometimes duplicates are propagated. It would be nice to see this problem addressed at the front end server. One of the problems I see in the SFO area is there are a lot of feeders that don't all have equal info as to be easily recognized by the software as the same plane.

If you want to see what I mean, follow the flights departing from KSJC for awhile. A lot of them have ghost FAA flights that follow them delayed by the famous five minutes.
FR24 is a European website and I guess they don't have that problem as much in Europe. But it is annoying to everyone watching flights departing from the USA

For what its worth, duplicate planes in areas where FAA data is available were very prevalent when I first started using FR24 a few years ago but it almost disappeared over time only to make a re-appearance coincidentally with the expansion of MLAT detection. If I recall correctly in those earlier times it showed planes on both FAA and ADS-B rather than FAA and MLAT. There are many annoying bugs that just seem to hang around in this program.

[Sam26K]

For what its worth, duplicate planes in areas where FAA data is available were very prevalent when I first started using FR24 a few years ago but it almost disappeared over time only to make a re-appearance coincidentally with the expansion of MLAT detection. If I recall correctly in those earlier times it showed planes on both FAA and ADS-B rather than FAA and MLAT. There are many annoying bugs that just seem to hang around in this program.

The problem seems not to be unique to FR24. PlaneFinder.net seems to have the same problem. Duplicate planes that are receiving different data by different feeders. One of the common denominators is that one of the feeds is missing the plane's tail number and/or squawk code.

One thing I've noticed with FR24 is when a plane is blocked due to BARR compliance, the plane doesn't always actually disappear from the real time map. It's just missing it's tail number. Not sure that specific case would create a duplicate plane but that is one of the symptoms of the duplicates that I do see.