Implementation and Characterization of a GNUradio multi-channel ADS-B receiver for space-based SDR application

Abstract

The work presented in this thesis shows the implementation of a multi-channel receiver for Automatic Dependent Surveillance Broadcast (ADS-B), a service for aircraft identification on a novel software-defined radio (SDR) platform, and the design of a sophisticated test bench for the qualification of ADS-B receivers that is used to characterize the performance of the implemented approach. The goal of this work was to implement the suggested receiver with the use of the GNURadio signal processing toolchain and to demonstrate the reception on up to four independent receive chains. The work thereby points out the benefits that come with this approach in terms of a more efficient development process compared to traditional software- and hardware-based approaches, and reduces the need for frequent and extensive cross-compilation. This documentation first describes the preparation necessary for the implementation of the suggested receiver system and the set of tools that was required. The receiver structure and the utilization of the SDRs hardware is explained, along with the required interfaces and libraries. The receiver is characterized thoroughly by a characterization process that relied on an integrated test bench which performed the evaluation tasks in form of a performance sensitivity analysis. The characterization defines a key parameter as a measure for the receiver performance. The receiver is evaluated against different parameters that are relevant for (space-borne) ADS-B receivers. The designed receiver was implemented successfully and showed working reception on up to four simultaneous receive chains. However, the characterization found major shortcomings with respect to processing speed and thus high message loss, which were associated with slow processing of the GNURadio implementation and the limited processing capacities of the embedded ARM processor. A field test demonstrated the functioning also outside the controlled lab conditions and an analysis of the received real-world ADS-B signals is presented. The results are summarized and an outlook is given on potential future challenges and tasks.