Data integrity augmentation by ADS-B SSR hybrid techniques

Scope of the paper is to present innovative solutions in cooperative surveillance domain for new generation systems for Air Traffic Management. The introduction of Mode-S protocol in Air Traffic Control (ATC) was originated by RF pollution resulting to broadcast interrogations/replies given by ATC Radar Beacon System (ATCRBS) interrogation mode. Broadcast (All-Call) transactions were so limited just to the initial acquisition phase, and then only one-to-one scheduled transactions (Roll-Call) were foreseen for the aircraft surveillance. In parallel to radar surveillance application, the association of spontaneous transmission (squitters¹) of Mode-S packets was developed, taking benefit from the communality of on-board equipment and installation, initially conceived for TCAS services. The Automatic Dependent Surveillance Broadcast (ADS-B) was conceived to give relief to Mode-S “radar channel” in terms of data throughput, and to cover wider geographical areas, mainly where radar installations were difficult or not economically sustainable. This gave the drawback to increase again RF pollution over 1090 MHz channel, as already highlighted since 2012. This is an external factor that drives a need for new approach to Mode-S Surveillance. Moreover ICAO has already given 2020 as deadline to solve this dichotomy, in which All-Call (broadcast) interrogations/replies have to be abandoned. Hybrid surveillance (Radar/ADS-B) is the most viable solution to take full benefits from Mode-S as an air-ground system, while avoiding RF pollution and keeping or raising the desired level of integrity, safety and security. This paper exposes a simple efficient technical solution for Mode-S hybrid surveillance. A state-of-art and innovative solution will be presented, focusing on limitations of the traditional system architecture and benefits of the proposed solutions in terms of improvement to the integrity of the delivered surveillance data, and of the hybrid acquisition process. A Test Bed has already been set up in Leonardo premises at Rome, and the first experimental data, expected to be available by mid-June, are also anticipated in the paper.