For example, an Ilyushin Il-76 will be around 5 pixels wide and long. The great bit is that these images are easily accessible (without login) for anyone, here.” “With their pixel size of 10 meters (at ground level), you are able to see and *just* able to identify aircraft. “Since around 5 years there are 2 Sentinel-2 satellites orbiting around Earth,” explained in an email to us. A Dutch image analyst and aviation tracker, he’s started working on publicly available satellite shots to gather additional details on the military activity all around the world exposed by Mode-S/ADS-B data. This is what our close friend has been increasingly exploring in the last few years. By combining ADS-B data with satellite shots you can get an even better “picture” of what is happening in a certain part of the world. In the last few years, other interesting tools have emerged to complement the ADS-B monitoring. MLAT uses Time Difference of Arrival (TDOA): by measuring the difference in time to receive the signal from four different receivers, the aircraft can be geolocated and tracked even if it does not transmit ADS-B/positioning data.Īlthough the majority of the aircraft you can track are still civil airliners and business jets, today, military aircraft belonging to different air forces as well as contractor and special operations planes can be regularly tracked while flying over Iraq, Afghanistan, Tunisia, Egypt, as well as over the Med, Black Sea, Baltic, South China Sea and and many other “hot spots”.
While not all aircraft broadcast their GPS data, in those areas where coverage is provided by several different ground stations, the position can be calculated also for those planes that do not broadcast their ADS-B data by means of Multilateration (MLAT) of their Mode-S transponder signals. Obviously, only ADS-B equipped aircraft flying within the coverage area of the network are visible. The flight tracking websites rely on a network of several hundred (if not thousand) feeders who receive and share Automatic Dependent Surveillance-Broadcast (ADS-B) transponders data and contribute growing the network and covering most of the planet. This information is transmitted on 1090 MHz frequency: ground stations, other nearby aircraft as well as commercial off-the-shelf receivers available on the market as well as home-built ones, tuned on the same frequency, can receive and process this data. The ADS-B system uses a special Mode-S transponder that autonomously broadcasts data from the aircraft’s on-board navigation systems about its GPS-calculated position, altitude and flight path. Here’s what we wrote about this technology in a previous article here at The Aviationist: Both these “services” (some of those are completely free, others requiring purchases to unlock some of the features), rely on Mode-S transponders with ADS-B capability.
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