Multilateration is a technology that has been in use for many decades in both navigation and surveillance applications. It was developed to accurately locate aircraft by using a method known as Time Difference of Arrival. MLAT works with all Mode A, C and S transponders.
How It Works
Aircraft without an ADS-B - out transponder do not broadcast their position or speed. In these cases, Radarbox, uses an aircraft`s Mode S transponder signals to accurately pinpoint the aircraft`s location using MLAT on 1090MHz.
Figure Above: Principle of the MLAT System
MLAT System Components
- MLAT generally requires a minimum of 3 receivers ideally (4+ receivers) in a particular area that can receive signals from the aircraft that is transmitting. This receiver units continuously listen for replies transmitted by the aircraft`s transponder.
- When a signal is broadcast from an aircraft`s transponder, it must be received by 3 or more ground stations. Since individual aircraft will be at defferent distances from each of the ground stations, their replies will be received by each station at fractionally different times.
- The Time Difference of Arrival (TDOA) is then measured. The TDOA basically calculates the time it takes the signal from the aircraft to reach the receiver. This is done by using advanced computer processing techniques and a central MLAT server.
- Once calculated, this data is then displayed on the Radarbox website.
RadarBox MLAT Coverage & Adoption
Currently, over 40% of the US and 65% of Europe and Japan have MLAT coverage. There is limited, but growing coverage in other countries such as Australia, India, Brazil, Bangladesh, the Philippines, Qatar, UAE and New Zealand. RadarBox is constantly working to improve MLAT coverage around the world and is targeting 80% coverage in the US & Europe by 2025.View MLAT Coverage