SpaceX just concluded 2017 by launching 10 Iridium NEXT satellites. A footnote on the launch was the “hosted payload” on board each of the satellites: a small box of equipment from Aireon. They will track every aircraft around the world in real-time, something that has been technically possible but nobody claimed they could do it economically until now.
Challenge one: avoid adding cost to aircraft. Instead of using expensive satcom or adding dedicated gear, Aireon listen to ADS-B equipment already installed as part of international air traffic control modernization. But since ADS-B was designed for aircraft-to-aircraft and aircraft-to-ground, Aireon had some challenges to overcome. Like the fact ADS-B antenna is commonly mounted on the belly of an aircraft blocking direct path to satellite.
Challenge two: hear ADS-B everywhere and do it for less. Today we can track aircraft when they are flying over land, but out in the middle of the ocean, there are no receivers in range except possibly other aircraft. Aireon needed a lot of low-orbit satellites to ensure you are in range no matter where you are. Piggybacking on Iridium gives them coverage at a fraction of the cost of building their own satellites.
These Iridium launches also create exactEarth, a maritime counterpart to Aireon that track ships via their AIS broadcast. The remaining Iridium NEXT satellites – and with them, these listening nodes – will launch next year to complete the network. Hopefully mysteries like Malaysia Airlines 370 will never happen again.
You don’t need a satellite network to join in the fun. You can listen to these data signals right where you are. We have a guide for receiving ADS-B sent by airplanes, and a guide for receiving AIS sent by ships.
21 thoughts on “Aireon Hitchhikes On Iridium To Track Airplanes”
This system really might help in tracking planes if something like 9/11 is to repeat.
Or, more likely, it narrows the search area when a plane goes missing.
It may still be very difficult to find them. If a plane is spinning on its way down, for instance, I imagine the satellite will not be able to get a lock on the signal. Depending on the altitude, you may end up with a huge radius as a search area. There is also the issue of power failure. Bear in mind that MH370 was equipped with an inmarsat unit and analysis of its data gave investigators a pretty good idea of where the plane was until it possibly ran out of fuel. Even with this information, they were not able to find the crash. So even with ADS-B+Aireon, it may still be a very difficult problem.
Quote: So even with ADS-B+Aireon, it may still be a very difficult problem.
Not so. The signal will give the GPS location, speed, altitude and direction. That is its purpose. The only catch is that there’ll need to be no way for a pilot to turn it off.
In contrast, the Inmarst signal took a lot of work to get even an approximate location. It was a mere handshake with the satellite. They had to extract a tiny bit of data from the response delay and the doppler shift.
Won’t help much as a terrorist could just turn the transponder off it’s also fairly easy to spoof the signals as well.
The aircraft used already had similar tracking hardware on them as it was required on commercial flights since the late 1980s.
I do like the idea that some aircraft are coming out with a floating “black box” that will connect via satellite and give a GPS location. The “black box” will release from the fuselage when it detects the plane is under water.
Sure, it may drift with currents or the plane may continue to glide for a while under the surface, but in addition to being a flight recorder, it will give searchers a location to begin.
“These Iridium launches also create exactEarth” – what is that supposed to mean? eE has existed for 8 years…
And here I was feeling smug for getting almost theoretical line-of-sight 400Km (215NM) limit ADS-B reception from the simple antenna I installed on my building roof a month ago
I wonder when this will start to show up on flight tracker websites. An ex-coworker once tried to convince me it was some conspiracy that the planes disappeared over the ocean when it was clear that there was just nothing to receive the data from them.
I’m not sure if it’s still ongoing, but last year FR24 were implementing an ADS-B receiver with a satellite relay on an ocean waverider. Read more here:
WHAT!? it’s mind boggling that we’d prefer to launch/maintain 10+ special satellites for this task rather than just requiring a low cost satellite modem in planes. Don’t overseas planes generally already have a satellite modem for internet? Why not just use that? I’m guessing the answer to all my questions is “ads-b is safety critical rated and will never fail”
This is not the primary function of the Iridium NEXT satellites, it is a secondary payload.
Who is this “we” you refer to?
Partly false story. Ads-b is not “already in all aircraft”. Ads-b was mandated a few years ago for all aircraft and still is only in a small portion of the civilian fleet. It costs about $7k to install. So you figure a 20k$ value c-152. That’s a huge chunk of cash for that aircraft. The compliance deadline is 2020. After that if your aircraft is not ads-b equipped its grounded. This is only the beginning. They can justify and get away with forcing this on aircraft. A person wont be able to fly from vegas to california without uncle sam watching. I feel its a huge violation of privacy. It was originally only intended that aircraft would see each other and atc can monitor within certain classes of airspace. Next step is this will be mandated for every car. You wont be able to drive from work to your girlfriends house without being tracked
ADS-B is not necessarily a $7k install. It’s not cheap, but it doesn’t have to be that bad. I installed ADS-B Out in my Champ for just under $4k, and could have gone cheaper. Less expensive options are coming on the market on a regular basis. There’s precious little data to back up my guess, but I’m guessing that a 2020-compliant plane is going to increase its market price by about the cost of the ADS-B install, so that it’s one of the few things that will be nearly 1:1 return on investment.
ADS-B compliance is only required within 30 nm of a Class B airspace, or within tower-controlled airspace (Class B: typically major airports you can fly into or out of with scheduled airliner service, like SEA, JFK, BOS, LAX, etc.; tower-controlled: small or medium airports with an active control tower, airspace usually 5 nm radius or less), which is the same airspace where a transponder is required now. In Washington State, that means that about 90% of the airspace doesn’t require ADS-B or a transponder, and you can still fly around without talking to anyone. If your plane was certified without an electrical system (think Piper Cub), you can still legally fly almost anywhere in the system, including within 30 nm of a Class B or into tower-controlled airspace, with no transponder and frequently with no radio.
I recently flew from Seattle to LA and back in the Champ. I could have legally done more than 90% of the trip without ever once talking to Uncle Sam or being identifiable on the radar (other than being “an aircraft with a transponder”). If I’d turned off the transponder, I would have only shown up as an object in the air, and could have legally made the same 90% of the trip. The government is doing a terrible job of implementing its surveillance state.
I think they need to stop doing stuff to make civil aviation more and more costly.
HaD said: “Aireon had some challenges to overcome. Like the fact ADS-B antenna is commonly mounted on the belly of an aircraft blocking direct path to satellite.”
So just HOW does Aireon overcome this challenge??
Now, THAT”S the hack!
By requiring a top mount antenna:
[insert sad trombone]
“In order to ensure reliable satellite reception, an A1 class transmitter and top mount aircraft antenna (commonly found on most commercial aircraft and private jets), is required due to the space-based nature of Aireon’s receivers. Aircraft with a Traffic Alert and Collision Avoidance System (TCAS) to help prevent midair collisions are typically equipped with both top and bottom mount antennas.”
Thanks, I’d wondered about that. Top and bottom antennas also means the signal won’t be blocked in a turn. Also keep in mind that this system has to be good, since it’s intended to prevent collisions.
Including these receivers with Iridium satellites is a marvelous idea since, unlike geosynchronous satellites, they’re intended to provided pole to pole coverage in low earth orbit.
This comment about belly mounted antennas is a bit missing the point because (as mention) TCAS equiped aircraft are required to have a top mounted antenna already. And anything worth tracking from space (“heavy metal” airliners and inter-continental range private jets) has a TCAS system already. Anything that doesn’t go over large expanses of open water can and will typically be tracked from the ground already.
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