Even when ANSPs decide to transition “straight to ADS-B,” multilateration processing at the ADS-B ground stations provides powerful benefits without additional costs or infrastructure.Given an ADS-B requirement for a given number of sites and aerodromes, multilateration provides a level of redundancy and validation, ostensibly for free with no additional ground stations.
The combined multilateration and ADS-B solution provides a number of benefits to ANSPs. First, the ANSP can offer separation services without mandating or waiting for 100% ADS-B fleet equipage.
Secondly, the ADS-B position reports can be validated with the simultaneous multilateration on those ADS-B transmissions. This assists not only in the transition stage, but also in the long term, where issues of legal liability on ADS-B data are still being discussed globally.
The multilateration system also acts as a real-time backup for the ADS-B surveillance network, especially in higher (en-route) elevations, but this can also be easily extended to lower levels and terminal approach. In the event of ADS-B interruptions (such as sun spot activity), surveillance capabilities can continue and total operational availability is greatly improved.
While leveraging the same ground stations means that multilateration is by definition more economical than secondary radar redundancy, the multilateration system’s performance also makes it capable of providing superior backup. Importantly, the update intervals can match or outperform ADS-B meaning system performance is maintained during outage scenarios
"MLAT will be an indispensable element to facilitate both the transition to ADS-B and the operational ADS-B phase itself.”
Heribert Lafferton and Dr. Roland Mallwitz, Surveillance Transition Scenerio for German Airspace, DFS Deutsche Flugsicherung GmbH>
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Without adding a single ground station to an ADS-B installation, MLAT provides additional coverage area – giving ANSPs equipage-independent surveillance, backup and validation.