Live in the Middle East? Have an internet connection? Want to identify the planes above your head?
Let’s talk about tracking planes.
The United States Air Force, and every air force, know what they’re doing. It’s literally their job. The USAF have hundreds of billions of dollars at their disposal, every year. Their commanders’ utmost priority is to ensure their mission gets accomplished, and is accomplished with minimal loss of life and equipment; no losses, if at all possible. They also know how their systems work, they’re professionals, but when the American public find out what they’re doing, via Twitter, they get cranky. David Cenciotti (of The Aviationist) has written about this multiple times; the following article was written in 2015, and it wasn’t his first.
I remember that article, and others David wrote; they were significant in developing my interest in tracking planes using open source methods.
There are multiple web sites which are well known to the open source community that track aircraft; FlightRadar24, FlightAware, RadarBox, ADSBexchange, etc.. but how they work, and their significant differences, are poorly understood by most. Only one of these flight trackers provides the public with a transparent representation of what’s above them, with no filtering-out of any individual planes, and that’s ADSBexchange.
Aircraft Transponders
At a high level there are two main ways planes are geolocated by flight tracking sites. Planes either identify themselves, and where they are, using latitude and longitude (as well as speed, altitude, etc), or they don’t identify exactly where they are, but still transmit their altitude, speed, etc.
Here’s what my own stand-alone receiver sees right now, with no help from other receivers. Each of those four planes is transmitting exactly where they are, how fast they’re going, what altitude they’re at, and what direction they’re going, among other details.
The innermost ring is at 100NM from my receiver, the 2nd and 3rd at 150NM and 200NM respectively. On a good day I can see planes coming from over 100NM away, but let’s be conservative and say my range is ~182km, or 100 Nautical Miles, to account for mountains or other environmental effects.
What if one ADSBexchange receiver was in each of the top ten largest urban areas in Iraq, that list would look like:
• Baghdad (population 7.2M, close to New York City, NY size)
• Basra (population 2.8M, close to Chicago, IL size)
• Hillah (population 1.7M, close to Phoenix, AZ size)
• Najaf (population 1.4M, close to Philadelphia, PA size)
• Karbala (population 1.2M, close to Dallas, TX size)
• Mosul (population 1.1M, close to San Jose, CA size)
• Erbil (population 1.0M, close to Austin, TX size)
• Sulaymaniya (population 1.0M, close to Fort Worth, TX size)
• Al Nasiriya (population 0.9M, close to Jacksonville, FL size)
• Kirkuk (population 0.9M, close to Charlotte, NC size)
This is a representation of where each of those cities are, in case you’re not familiar with Iraqi geography.
From Erbil to Kirkuk is just under ~100km, as the crow flies, so that’s the yardstick I’m going to use for hypothetical coverage, to be conservative, due to terrain. Each pink shaded zone shows where planes, which transmit their latitude and longitude as part of their ADS-B transponder traffic, should show up. Only one receiver is needed to identify a plane, and put it on the map; but only if they are transmitting their own latitude and longitude.
This is a fictional example of a coverage map if there were ten transponder receivers spread out across Iraq’s biggest cities; any aircraft crossing through those red bubbles (SHOWN IN BLACK BELOW) broadcasting their position using an ADS-B transponder would show up on ADSBexchange; Aircraft outside of those bubbles (SHOWN IN GREEN BELOW) will simply not show up on the map until they’re in the coverage area. They aren’t using any sort of stealth technology, this has nothing to do with radar coverage, and they aren’t even trying to hide. Our tools simply cannot provide better coverage of Iraqi airspace without more Iraqi hobbyists contributing to the effort.
Mode-S / MLAT Coverage
Unfortunately, deploying ten receivers that would feed ADSBexchange, in ten different cities, doesn’t provide adequate coverage to identify planes that don’t transmit their precise location, and ten receivers cannot provide corner-to-corner coverage of Iraq. Planes that use Mode-S do not transit their lat/lon, and have to be triangulated from he ground. To do that, we need them to be in the overlapping area of coverage of four of those bubbles simultaneously. You can see where the circles intersect, and if four circles overlap, AND there is a plane in that area, it will show up, but only briefly, until they fly out of the intersection of the four coverage areas, of the four receivers. How do you fix that? Brute force; we need more receivers to feed into ADSBexchange.
Aircraft that do not transmit their location are still visible to adversaries; adversaries have radar, HUMINT, as well as SIGINT/ELINT capabilities that are outside my capacity as a civilian. It is realistic, and likely, that Iran can “see” many aircraft over Iraq using their own national technical means; they’re right next door. MLAT is short for Multilateration; “Multilateration is a technique for determining a ‘vehicle’s’ position based on measurement of the times of arrival of energy waves having a known speed when propagating either from or to multiple system stations.” per Wikipedia. If each of the top ten largest cities in Iraq had multiple ADSBexchange receivers, say six per city, each spread out around the city to allow for triangulation of aircraft, we would have a much better idea of what kind of air operations take place above Iraq on a daily basis, and not be limited to what we’re told. Receiver antennas can be placed on apartment building balconies, window sills, and on top of people’s roofs; the higher the better, with as much of a view of the sky as possible. I don’t expect to be able to find people everywhere in Iraq who are able to operate a SDR-based transponder receiver, but I think we should be able to find some with reliable internet access, but it’s not impossible
The effort to triangulate aircraft flying over the middle east doesn’t need to be confined to Iraq, the emissions being broadcast by these planes cross international boundaries. Look at any map of the region; many people in any country in the region could contribute to monitoring the air over the middle east for smuggling, mercenary transport, arms transfers, personnel movements, or reconnaissance aircraft, or anything over the region.
What’s with the refuelling planes over Iraq?
As mentioned, Iraq doesn’t have a lot of ADSBexchange receiver coverage, and you’re lucky when you even get one receiver in range of a plane, let alone four. USAF KC-135s frequently only use Mode-S over Iraq, which means you need four overlapping coverage areas to triangulate the aircraft (remember the graphic above?). Over the holidays, aviation tracking enthusiasts noticed what looked like a surge in KC-135 refuelling aircraft over Iraq.
While some people have drawn the conclusion there is an increase in USAF air traffic over Iraq, I’m skeptical, because we have such poor coverage of the middle east with open source tools. I suspect FlightRadar24 started getting fed from some newly installed feeders in Iraq recently, and this is the result; an increased awareness of KC-135 air-to-air refuelling planes operating over Iraq, that could have been happening with the same frequency before, but we just didn’t see them.
I believe the best way to improve the visibility of aircraft over the Middle East is to make new friends there, who are willing to collect data being transmitted by the aircraft over their heads, ask them to feed that data to ADSBexchange, which helps the public monitor aircraft globally, bypassing traditional corporate masters, governmental organisations, and militaries of the world.
If you’re on the planet Earth, you can be part of the solution, and set up a receiver yourself.
As featured on RTL-SDR.com
Here is how to set up a receiver and feed to ADSBexchange (Thanks Tom!)
Here is the official ADSBexchange web page that is up to date with install scripts and information to join their Discord server.
