SATERA Baseline: Identifying the Challenges of Space-Based Multilateration Systems

<p>Air traffic control traditionally relies on Secondary Surveillance Radar (SSR) and procedural methods in areas without radar coverage. In recent years, ADS-B has gained<br>importance as a surveillance technique that transmits the identity and position of aircraft. Space-based ADS-B (SB ADS-B) systems extend this capability by enabling transmission to satellites, particularly in remote and oceanic regions where ground stations are not feasible. Not only does this contribute to the reduction of separation between aircraft, but it also increases airspace operational efficiency by enabling more direct routes and greater availability of optimal altitudes, which in turn leads to lower greenhouse gas emissions. However, the integrity of ADS-B transmissions can be affected by either natural or intentional perturbations. To address this issue, the SATERA project aims to develop an integrity estimator for SB ADS-B systems using position estimates provided by multilateration (MLAT) systems. This work contributes to establishing the project’s baseline and identifying specific challenges. A prediction tool has been developed to calculate the theoretical performance of an MLAT system<br>using receiver stations aboard a constellation of Low Earth Orbit (LEO) satellites. The methodology involves adapting ground-based MLAT localization algorithms to the space environment, evaluating regularization techniques to mitigate potential ill-conditioning, and using advanced Kalman filter-based tracking algorithms combined with the Interacting Multiple Model (IMM) filter.</p>