Is a Turkish UAV currently operating inside the Iraqi airspace?

Mar 13 2016 - 2 Comments

What might be an Unmanned Aerial Vehicle is circling over the border between Turkey and Iraq.

Increasingly, military aircraft as well as UAVs can be tracked online thanks to the emissions of their Mode-S ADS-B-capable transponders.

In fact, these aircraft do not broadcast their ADS-B data but their position can be determined by means of Multilateration (MLAT).

MLAT (used by Flightradar24.com) uses Time Difference of Arrival (TDOA): by measuring the difference in time to receive the signal from aircraft from four different receivers, the aircraft can be geolocated and followed even if it does not transmit ADS-B data.

This means that the majority of the aircraft you’ll be able to track online are civil airliners and business jets that broadcast their callsign, altitude, position and speed via ADS-B in a cooperative way to let ground stations and nearby aircraft aware of their presence, whereas military aircraft (like the U.S. Special Operations aircraft daily flying over North Africa) equipped with Mode-S ADS-B-capable transponders can be tracked even though they are not broadcasting their position, because they can geolocated with MLAT.

What is happening right now over northern Iraq is at least weird.

A small aircraft or most probably a UAV, whose track appear to have originated from Turkey, is circling over northern Iraq, north of Mosul, being tracked by a feeder (a user with commercial off-the-shelf receiver available on the market) located in Erbil.

What’s unusual is that the aircraft, provided it is a UAV, is transmitting its data in the clear for everyone to see. Usually, aircraft (either manned or unmanned) performing clandestine missions can be tracked thanks to MLAT and not because their ADS-B transponder is turned on….

Any idea? Is it a drone or a small plane?

TuAF UAV over border 2

Image credit: Flightradar24.com

  • su34

    The fundamental misunderstanding is perpetuated that, if a certain air
    asset doesn’t want to be (“easily”) detected (military/covert ops/etc),
    it would not broadcast ADS-B packets but will keep responding to SSR
    inquiries (mode-A/C/S), or even broadcast mode-S “squitters”.
    ADS-B receivers (1090Mhz) used by FA or FR24 can also receive mode-S packets, or “squitters”, but, without the on-board GPS determined position extended payload, can’t know the position. In the latest versions of the Rx SW (up from a few months ago) mode-S packets received by more than 2 ADS-B Rxs, can be used to tri-/multilaterate the emissions source, deriving rough position data through TOA timestamping. It’s practically a similar procedure to that used by LORAN-C Rxs (TDOA), for decades, but without a local Rx time reference, wich was not needed due to the precise synchronisation of LORAN-C chains. While the LORAN-C chains transmitted precisely synchronized (usually by Cs time references) pulses, the usual ADS-B Rx SW has only an NTP reference, which is much too imprecise for the purpose (a local GPS time reference would be needed for precise timestamping, but not used by current implementations). Even if LORAN offered a few orders of magnitude less accuracy than GPS, current ADS-B MLAT would be even much more inaccurate (kms to tens of kms at best).
    Obviously it’s not the case with the presented track, that has it’s data derived from ADS-B packets, so the asset’s owners deliberately wanted it’s existence known.

  • disqus_STXkrV9NGc

    Could be just superman roaming with location services