Validation of a software-defined baseband system for satellite telemetry and telecommand

This paper presents the validation of a software-defined baseband (SDB) system for satellite telemetry and telecommand (TM/TC). The baseband system was developed using the open-source GNU Radio development kit. It runs on a personal computer connected to a commercial-off-the-shelf (CoTS) RF frontend. The validation process was performed by the use of a mission-qualified satellite emulator, a state-of-the-art baseband unit, and orbiting satellites. The baseband is designed to offer multimission support. Hence, it includes a suite of modulation schemes, line codes, matched filters, and Consultative Committee for Space Data Systems (CCSDS) forward error correction codes (convolutional, Reed–Solomon, concatenated, and low-density parity-check [LDPC]) typically employed in TM/TC missions. The figures of merit used for the validation of the TM receiver are bit error rate (BER) and frame error rate (FER). For the TC transmitter, the validated features are modulation index, power spectrum, and the physical layer operations procedures (PLOP).Validerad;2021;Nivå 2;2021-10-20 (alebob);Funder: Swedish Space Corporation (SSC) ; Rymd för Innovation och Tillväxt (RIT)</p

Analysis and Synthesis of Metadata Goals for Scientific Data

The proliferation of discipline-specific metadata schemes contributes to artificial barriers that can impede interdisciplinary and transdisciplinary research. The authors considered this problem by examining the domains, objectives, and architectures of nine metadata schemes used to document scientific data in the physical, life, and social sciences. They used a mixed-methods content analysis and Greenberg’s (2005) metadata objectives, principles, domains, and architectural layout (MODAL) framework, and derived 22 metadata-related goals from textual content describing each metadata scheme. Relationships are identified between the domains (e.g., scientific discipline and type of data) and the categories of scheme objectives. For each strong correlation (\u3e0.6), a Fisher’s exact test for nonparametric data was used to determine significance (p \u3c .05). Significant relationships were found between the domains and objectives of the schemes. Schemes describing observational data are more likely to have “scheme harmonization” (compatibility and interoperability with related schemes) as an objective; schemes with the objective “abstraction” (a conceptual model exists separate from the technical implementation) also have the objective “sufficiency” (the scheme defines a minimal amount of information to meet the needs of the community); and schemes with the objective “data publication” do not have the objective “element refinement.” The analysis indicates that many metadata-driven goals expressed by communities are independent of scientific discipline or the type of data, although they are constrained by historical community practices and workflows as well as the technological environment at the time of scheme creation. The analysis reveals 11 fundamental metadata goals for metadata documenting scientific data in support of sharing research data across disciplines and domains. The authors report these results and highlight the need for more metadata-related research, particularly in the context of recent funding agency policy changes

OpenSource based Voice Communication for Mission Control

Voice communication is a critical service within Mission Control Rooms, as voice communication is the most practical and precise way to transmit information between human beings. It is used in any control room environment for space mission support to enable collaboration within the room and to external connected entities. Today’s systems are highly specialized turnkey-based vendor solutions, which are inflexible in terms of adaptability and extension capabilities. These systems are based on vendor related proprietary protocols and are built on top of voice distribution technologies. In this paper we describe the core of a Voice Communication System (VoCS), which directly integrates the special requirements needed for Mission Control Room environments. Our solution will enable an overall system design with component-based implementations and interoperability between different vendors for different parts of the system. In addition our definition of the VoCS core will allow different levels of integration into existing infrastructures, as well as client implementations in the range from fully dedicated hardware-based infrastructures up to the provision of VoCS functionality within Web-based implementations. We will describe the idea using a prototype implementation based on FreeSWITCH, an Open Source media backend with a carrier grade cross-platform multi-protocol soft-switch, and the most differentiating client solution to common VoCS clients, a full virtual Web-based client