# What are the recent developments in the satellite-based tracking of aircraft?

I find it pretty unsettling that in 2016 it is still not possible to track transoceanic flights using flightradar24 or flightaware, because of lack of coverage.

When the unfortunate MH370 accident occurred, I stumbled upon news of the British company Inmarsat launching, or discussing the launch of, a series of satellites to help track transoceanic flights anywhere in the World, that could also be useful to determine vertical separation.

Quite a few months have passed and I seem to have lost track of this. So I am here to ask those who know more about it:

what are the recent developments in the satellite-based tracking of aircraft?

• aireon.com is another company you may find interesting – J. Hougaard Dec 12 '16 at 19:26

The German Space Agency (DLR) worked with ESA to track flights from space using ADS-B, the same technology behind flightaware etc. Some info about it is here

A commercial entity, called Aireon, is planning a global constellation to monitor aircraft that will piggy-back upon the next generation of Iridium satellites. But, unfortunately, the recent setbacks to SpaceX launch capabilities have delayed Aireon's schedule. The first launch of the Iridium-NEXT satellites occurred on Jan 14th 2017 and the entire constellation - providing near global ADS-B coverage - is planned to be complete by mid-2018.

Aside from ADS-B, there is also research going on to track aircraft through their exhaust emissions (something I'm working on right now). Nothing is published about that yet, though.

• Can we have an update to this answer now that there are some Iridium-NEXT birds in orbit? – UnrecognizedFallingObject Feb 4 '17 at 20:30
• @UnrecognizedFallingObject updated! – os1 Feb 5 '17 at 9:56

Everything has been developed already. Geostationary satellites cover +/- 70° latitude. Many aircraft are equipped to communicate through geostationary satellites for telephony, internet, or tele-monitoring. In the MH370 event, the engines (!) have sent some data packages to the manufacturer. This is how we got to see these circles of MH370's last position, even though the position was never transmitted over satellite.

It would be very simple to transmit the GPS position through satellite. Only while flying over the poles, communication would be slightly more complicated.

Of course, somebody would have to pay for the data bandwidth. To do it, or not is merely a commercial decision, and not a technical challenge any more. One fact that is easily overlooked is that constant monitoring would add very little to aircraft safety. How much are the airlines (and the travellers) willing to spend to make the relatives of crash victims feel better?

• Geostationary satellites are sufficiently far away that the 70° latitude restriction is solely due to near-surface effects. A plane 30.000 feet above either pole can communicate with all geostationary satellites. – MSalters Dec 14 '16 at 0:13
• @MSalters This is unlikely. Antenna elevation for GEO satellite is 0° around 80° latitude, about -8° over the pole. A top mounted antenna has no line of sight when cruising over a pole. Side mounted antennas would be possible, but the signal attenuation due to the long path through atmosphere goes significantly up, and the noise due to ground interferers goes up as well. An excessive power margin would be needed to maintain a useful SNR. Do you have any example for civil aircraft maintaining a link to a GEO sat over a pole? – Jenc Dec 21 '16 at 14:50
• Whoops, my bad. That should be 80 kilometers above the poles, which is 250.000 feet, so 30.000 feet is way too low. Another problem would be that you may have line of sight, but many satellites use fairly narrow beams so they don't waste power. It can be a design decision to not cover areas north of 70° latitude. – MSalters Dec 22 '16 at 13:04

There are initiatives taking place to provide satellite based ads-b service to aircraft. As a caveat, this doesn't necessarily mean that you will be able to see the data on FR24 or FA via the internet, at least the way it is currently. The implementation is through a complicated network of various entities.

• ICAO Since the disappearances of AF447 and MH370 hey have created the Global Aeronautical Distress Safety System (GADSS) which will allow airlines to be able to track aircraft anywhere on earth. This is just a set of standards the airlines must comply with. It's intended to go into effect in 2018.

• Aireon This is a company formed as a joint venture between Nav Canada, which is the Canadian ATC provider, and Iridium, a communications company that operates a network of satellites. Iridium is launching the next generation of satellites into orbit and through Aireon they will be providing ads-b service.

• FlightAware As well as the information you can see on their website they now offer fee-based access to their large database of flight information and tracking data.

• Globalbeacon This company was formed as a partnership between Aireon and FlightAware. (Like I said, complicated) This company will provide global tracking service to airlines through FlightAware's web infrastructure so they can be compliant with GADSS. [Btw, they have an implementation timeline on their site. ]

• SITAOnAir This company provides airborne Wi-Fi, cell phone and passenger entertainment services. They also provide flight planning services to the airlines. They are partnering with Aireon and FlightAware to add ads-b tracking to the services they provide the airlines. [This company was originally formed as a joint venture with Airbus.]

Since this is a conglomeration of governmental, private, non-profit and United Nations organizations, each plays a part in the implementation of of worldwide satellite coverage.

What is somewhat unclear is how this will effect the publicly accessible tracking info. Flightaware will certainly have the capability to add trans-oceanic data, but they seem to be adjusting their business model toward providing data to paying corporate customers. I don't find any information as to whether or not global coverage will become a part of the website.

FlightRadar24 operates mostly on a network of volunteer hosts with ads-b receivers. They won't have access to satellite data unless they enter into an agreement with one of the above companies. Once again, I can find no information as to whether this is in the works or not.

Just because FR24 and Flightaware don't show anything doesn't mean that the information is not available.

FR24 and Flightaware are not the only systems out there; there are several others if you care to search, and many of them are not subject to the same restrictions as FR24 and FA.

There are already (and have been for quite a few years) uplinks and downlinks from the various ATC agencies and aircraft. If you know which satcom frequency bands, and have a suitable decoder program, it is relatively easy to 'eavesdrop' upon the uplinks and downlinks. Many aircraft are already sending their positions on a regular basis, and it's just a case of plotting them all.

For example, at the moment I'm seeing almost 30 aircraft crossing the north Atlantic, and each of these is 'out of range' of the regular ADS-B listeners who feed data into FR24 and Flightaware.

Here's an image of the north Atlantic during a busier period (07.30am UTC)

• This isn't really a solution, however, as it's not comprehensive. For example, you can 'see' 30 aircraft but there are far more than 30 aircraft over the atlantic at any given time. The fraction that get missed is important: And that's far higher with a ground-based system such as this rather than using satellite-based ADS solutions. – os1 Dec 14 '16 at 8:30