a few days ago, a measurement campaign took place above Berlin, where two airplanes (C207T, D-EAFU, owner: Free University of Berlin, Institute for Space Sciences | D228, D-CFFU, owner: DLR), equipped with several spectrometric instruments, flew a north-south pattern above the city in two flight levels primarily to map NOx emissions. Now, some colleagues (including me) at both institutes recognised the strange pattern of the Dornier in FL200 showing in FR24, which led to some discussions:

Could someone explain, what happend with the MLAT-tracking of the Dornier? It seems that the accruacy and spatial resolution is reduced dramatically above ~FL100. I was speculating that the (probably) high density of Mode-S/ADS-B receivers around Berlin can't capture the signals because of the mostly (co)llinear antenna designs, so a lot of the ground stations were not able to catch signals of the Dornier and therefore the multilateration accuracy is poor.

Any suggestions?

Best regards,