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    Development, implementation and integration of key performance indicators within the GIOVE mission segment
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    Abstract:
    The Giove Mission Segment (GIOVE-M), part of the Galileo In-Orbit Validation (IOV) risk mitigation program, is supported by a ground infrastructure comprising the Giove Processing Centre (GPC) located at ESTEC and a worldwide network of Galileo Experimental Sensor Stations (GESSs). The GPC supports the data collection from the GESSs and the near real-time processing and uploads of the Navigation Messages through the Ground Control Centres. The space element of the GIOVE-M consists of the GIOVE-A and GIOVE-B satellites. One of the fundamental functions of the Giove Processing Centre is to continuously monitor its system and processing functions as well as the quality of the collected data from the GESS network to ensure uninterrupted Operations and quality of the services provided to the GIOVE-M experimenters. Following the recent launch of GIOVE-B a number of upgrades to the GIOVE-M infrastructure have been required to support the expected experimentation and risk mitigation activities. In particular the GPC is being upgraded to implement new capabilities to generate and report on a set of Key Performance Indicators to continuously measure the quality of the GPC processing. The Key Performance Indicators (KPI) cover the areas of the Navigation Message performances including the Orbit Determination and Time Synchronization (OD&TS) processing performances, the Orbits and Clock prediction accuracy, the Experimental Galileo to GPS Time Offset (EGGTO) determination and prediction accuracy, the Broadcasted Group Delay (BGD) stability and the input data latency and completeness for the OD&TS processing. The KPI will also cover the Experimental GIOVE System Time (EGST) stability, the Intersystem Bias and the delay and validity of the generated and received Navigation Messages. The Key Performance Indicators are generated by a software tool developed on a dedicated Giove Processing Centre facility. The present paper describes the initial design and subsequent development of the Key Performance Indicators tool. Initial results of this as well as the configuration, statistics and reporting capabilities of the tool are also presented. The issues, limitations, advantages and strategies that have been adopted to critically evaluate the Key Performance Indicators over the near real-time GPC processing are also discussed. The paper concludes by reporting on the major interest of the KPI tool with regards to the future Galileo operations in particular in terms of consolidation of the mission support facilities needs.
    Keywords:
    Galileo (satellite navigation)
    Upload
    Data Processing
    The Space Communications and Navigation (SCaN) is a facility developed by NASA and hosted on board the International Space Station (ISS) on an external truss since 2013.It has the objective of testing navigation and communication experimentations with a Software Defined Radio (SDR) approach, which permits software updates for testing new experimentations.NASA has developed the Space Telecommunications Radio System (STRS) architecture standard for SDRs used in space and ground-based platforms to provide commonality among radio developments to provide enhanced capability. The hardware is equipped with both L band front-end radios and the NASA space network communicates with it using S-band, Ku-band and Ka-band links.In May 2016 Qascom started GARISS (GPS and Galileo Receiver for the ISS), an activity of experimentation in collaboration with ESA and NASA that has the objective to develop and validate the acquisition and processing of combined GPS and Galileo signals on board the ISS SCaN testbed. This paper has the objective to present the mission, and provide preliminary details about the challenges in the design, development and verification of the waveform that will be installed on equipment with limited resources. GARISS is also the first attempt to develop a waveform for the ISS as part of an international collaboration between US and Europe. Although the final mission objective is to target dual frequency processing, initial operations will foresee a single frequency processing. Initial results and trade-off between the two options, as well as the final decision will be presented and discussed. The limited resources on board the SCaN with respect to the challenging requirements to acquire and track contemporaneously two satellite navigation systems, with different modulations and data structure, led to the need to assess the possibility of aiding from ground through the S-band. This option would allow assistance to the space receiver in order to provide knowledge of GNSS orbits and reduce the processing on board. Trade off and various options for telemetry and uplink data are presented and discussed. Finally, integration and validation of the waveform are one of the major challenges of GARISS: The Experiment Development System (EDS) and the the Ground Integration Unit (GIU) for VV will be used prior to conducting the experiment on the ISS. The EDS can be used in lab environment and allows prototyping and verification activities with the simulator, but does not include all hardware components. The GIU on the other side is the flight model which replicates the flying equipment, but has limited flexibility for testing.As conclusion, the project is now approaching the Preliminary Design Review (PDR) and indeed only preliminary results are available. This paper is an opportunity to present the GARISS mission as part of an International cooperation between ESA, NASA and Qascom. The preliminary results include GPS and Galileo processing from space signals, the challenges and trade off decisions, the high level STRS architecture and foreseen experimentation campaign. Detailed results from the test campaigns are expected in 2017.
    International Space Station
    Testbed
    Galileo (satellite navigation)
    Communications satellite
    Citations (0)
    The Galileo Ground Mission Segment (GMS) plays the major role in the provision of the Galileo world-wide navigation and integrity services with demanding levels of real-time performances availability, accuracy, continuity and integrity. The GMS is hosting all key functions of the Galileo global component, which are implemented in fourteen different types of elements in order to achieve the main Galileo mission objectives: Four of them, namely the Galileo Sensor Stations (GSS), the Orbitography and Synchronisation Processing Facility (OSPF), the Integrity Processing Facility (IPF) and the Precision Timing Facility (PTF) represent the main processing facilities of the GMS and they are in charge of determining all navigation and integrity data for each level of service (open service, safety of life service and public regulated service). The dissemination of the service data (including those captured from Service Providers) towards the Galileo satellites or towards Service Centers is executed by the Message Generation Facility (MGF) and the Up-Link Stations (ULS). While these first six facilities are designed to operate fully autonomously with a high reliability in order to ensure and to provide an uninterrupted service to all Galileo users, four other element types, namely the Ground Assets Control Facility (GACF), Mission Uplink Control Facility (MUCF), Mission Support Facility (MSF) and Maintenance and Training Platform (MTPF) cover the various operability needs, which comprise mainly basic technical monitoring and control of all GMS elements, on-line mission monitoring and off-line mission analysis. Two types of facilities (MKMF/PKMF) are in charge of data protection and key management as well as management of the various related security modules. A last element type, namely the Service Product Facility (SPF) is dedicated to the implementation of the exchange zone between the GCC and the external world. A Mission Data Dissemination Network (MDDN) with unique features is in charge of the world-wide interconnection of the GMS sites and provides a very low latency, high availability and continuity. The MDDN is monitored and controlled by the Ground Network Management Facility (GNMF). The GMS design and performances were reviewed in the frame of the Critical Design Review (CDR), which was successfully executed in second quarter of 2008. This paper provides an up-to-date overview of the main GMS design features as presented at this major Galileo milestone and gives an insight into the architecture formed by all those elements. Furthermore the paper addresses the key design choices and trade-offs, the level of redundancy and specific safety features and barriers fulfilling the needs for safety related applications. Finally the paper presents the major results of the GMS performances achieved for the CDR
    Galileo (satellite navigation)
    Facility management
    Mission control center
    Citations (2)
    TDP-1 is a quasi-operational technology demonstration payload, designed to prove the concept of data transfer between low-orbit observation satellites and earth via a geostationary relay satellite in between the communication chain. This detour allows to significantly increase transferable data volume at reduced latency time, and is performed with the help of Laser Communication Terminals (LCTs) on board the low-orbit as well as the geostationary satellite, from which the data is immediately downlinked via Ka-Band. In this framework, TDP-1 is the successful precursor mission for the forthcoming European Data Relay Satellite System (EDRS). A dedicated operational concept has been developed by DLR GSOC as TDP1 Mission Control Center. The concept is based on heritage programs TerraSAR-X and NFIRE and includes all necessary tasks and steps like calculation of feasible link slots based on satellite orbit and availability data, scheduling of customer link requests, and generation of operational products for the involved spacecrafts to execute the links. This paper gives an overview of the current Mission Control Center System Design of the TDP-1 program and its operational experiences.
    Payload (computing)
    Ground segment
    Communications satellite
    Data link
    Mission control center
    Data center
    Citations (0)
    The work presented in this thesis focuses on the design and implementation of software solutions for the ground segment of satellite missions, with application to the ESEO mission. The ESEO project is currently in Phase D after successfully passing the preliminary and critical design reviews and the launch is foreseen in 2017. Starting from our experience with ALMASat-1 mission, we greatly improved the ground systems for a more complex mission like ESEO. One of the most important improvement is the introduction of a Software Defined Radio with a dedicated software application acting as a transceiver capable of communicating with the on-board transceiver at the registered frequencies and using the defined communication protocol and modulation scheme. It also displays and registers the acquired signal for post-processing tasks. The spacecraft monitoring and control system and the telemetry data visualisation and display tool have been designed keeping in mind the high number of subsystems and payloads and the possibility to re-use the same software for future missions with the minimum effort. The introduction of a connection to a database is essential considering the high number of spacecraft and mission data. This thesis also presents the software solutions designed and implemented for ground stations used by EUMETSAT to operate LEO and GEO weather satellites. The Ground Station Analysis and Reporting tool was developed to allow engineers checking through periodic reports the performance of two ground stations located in Svalbard. The Satellite Passes and Conflicts Engine supports now the schedule of Metop and NOAA satellite passes over Svalbard ground station and it can be used to compute passes and resolve conflicts of multiple satellites over multiple ground stations based on the propagation of the TLEs. Finally, a ground station monitoring and control simulator has been implemented and fully tested for the MTG programme.
    Ground segment
    Transceiver
    Ground station
    Communications satellite
    CNES is involved in a GPS (Global Positioning System) geostationary overlay experimentation. The purpose of this experimentation is to test various new techniques in order to select the optimal station synchronization method, as well as the geostationary spacecraft orbitography method. These new techniques are needed to develop the Ranging GPS Integrity Channel services. The CNES experimentation includes three transmitting/receiving ground stations (manufactured by IN-SNEC), one INMARSAT 2 C/L band transponder and a processing center named STE (Station de Traitements de l'Experimentation). Not all the techniques to be tested are implemented, but the experimental system has to include several functions; part of the future system simulation functions, such as a servo-loop function, and in particular a data collection function providing for rapid monitoring of system operation, analysis of existing ground station processes, and several weeks of data coverage for other scientific studies. This paper discusses system architecture and some criteria used in its design, as well as the monitoring function, the approach used to develop a low-cost and short-life processing center in collaboration with a CNES sub-contractor (ATTDATAID), and some results.
    Ground station
    Transponder (aeronautics)
    Data Processing
    Citations (0)
    This paper describes the purpose, methodology, and conclusions of a performance analysis characterization for a nano-satellite mission. The mission concept includes two key requirements which are critical for mission success, collection capacity and data latency. An analytical toolset was developed to evaluate mission performance against these key requirements. Models of the spacecraft data storage system, power system, and primary payload were developed in addition to the communications architecture. A simple collection and downlink scheduler was implemented to evaluate collection capacity and latency. Initial results indicated that the mission design was flawed as the communications architecture was vastly undersized for the amount of mission data capable of being collected. Trade studies were conducted to determine a communications architecture that supported the spacecraft collecting at peak operation levels. Identification of a modified architecture along with the supporting analysis was critical in properly focusing efforts to maximize mission utility.
    Payload (computing)
    Communications satellite
    Citations (0)
    Time synchronization between satellite and the earth is an important part of the navigation and positioning system. Time synchronization mission scheduling evaluation is the basis of satellite project design and improving satellite navigation system running efficiency. In view of the evaluation of the navigation satellites task scheduling, a multi-level measurement index system based on task, resource and performance is set up. A general comprehensive evaluation frame is constructed. At last, it demonstrates method feasibility by analyzing the computational results. The method provides the decision support for the navigation system's top-design and the optimization of the ground recourse's allocation.
    Citations (0)
    A design approach common to the areas of satellite operations command and control, tracking, subsystem analysis, system planning and scheduling, orbit determination and maintenance, and data routing and control is discussed. Specific satellite mission applications and operations are isolated from the remainder of the design to allow application to a broad variety of satellite systems. Discussions of specific satellite missions are limited to the context of understanding the general magnitude and scope of what a ground control facility is required to support. By isolating the common satellite operational functions, a low cost generic approach that allows for phased implementation of system changes with minimal impact to on-orbit assets and mission performance is developed. The goals of this approach are to provide the capability for growth, maintainability, and operability of the satellite system. A brief discussion of satellite systems followed by the introduction of the general function of any satellite control facility sets the stage for the overall design approach. The factors that define the design along with the key design features are presented, with a discussion of each product available in each functional area.< >
    Maintainability
    Scope (computer science)
    Citations (9)
    Abstract : Under contract to the European Space Agency (ESA), an expert team lead by Kayser-Threde GmbH has elaborated a design concept for the Precise Time Facility (PTF) for Europe's satellite positioning system Galileo. The major purpose of the PTF is to generate, maintain, and distribute Galileo System Time (GST). The PTF is represented by an ensemble of atomic clocks (active H-maser, cesium) with appropriate measurement equipment and time algorithms. In addition, Two-Way Satellite Time and Frequency Transfer (TWSTFT) and GNSS Common-View (CV) equipment is included, since GST will be steered to TAI by linking the PTF master clock to selected European National Metrological Institutes (NMI). This process shall be managed by the yet to be established external Galileo Time Service Provider (GTSP). During Galileo In-Orbit Verification (IOV), one PTF is planned to be physically implemented, whereas for Final Operational Capability (FOC) two identical and redundant PTFs at two different sites in Europe are foreseen. A preliminary PTF turn-key architecture has been proposed in 2003 by the team. This architecture has been further detailed during the 2004 Phase C0 study. The architecture is entirely based on the results of the previous Galileo system studies and the requirements derived thereof. In addition, the proposed turn-key design covers a number of features which are deemed key to successful and timely procurement, installation, and operations of the PTF during IOV and FOC. Concerning the PTF design baseline, the redundancy mechanisms and a reliable connection between the PTF and the GTSP are considered to be more critical than the GST generation and steering algorithms, where valuable experience exists worldwide at the NMIs.
    Galileo (satellite navigation)
    Time transfer
    Citations (2)
    The Galileo user receiver represents a key technology and is at the heart of the user segment. It is the main physical interface between the system and the user and transforms the Galileo Signal-in-Space into services for the citizen. Within the project GAMMA a consortium of nine industrial and research partners lead by Fraunhofer IIS of Nuremberg, Germany, are developing an assisted Galileo/GPS/SBAS satellite receiver prototype and a multi channel Galileo/GPS/SBAS signal generator to evaluate the performance of the receiver. The project has also investigated a number of assistance strategies to enhance the positioning accuracy and reduce the time to fix based on interaction with commercial 2G and 3G cellular networks, such as GSM and UMTS. Further work encompassed a study of indoor navigation capabilities, reconfigurable and hence reusable digital hardware components for GPS, SBAS and Galileo, assisted acquisition concepts, and, finally, low cost optimizations. The project has started in November 2005 and will run 24 months until October 2007. The initial work focused on market studies, application scenarios, specification and system design. Currently, the developments are almost completed and first tests have already been carried out. The paper puts special emphasis on the constellation simulator: The implementation, as well as performance benchmarks with respect to real satellite orbits will be discussed. Next to that, the results from the research on the design of a Realtime Baseband Generator are addressed. The Realtime Baseband Generator provides the constellation specific satellite signals taking all relevant effects and channel impairments into account, based on the model parameters provided by the constellation simulator.
    Galileo (satellite navigation)
    GSM
    GNSS augmentation
    Citations (3)