The applications of satellites to communications, navigation and surveillance for aircraft operating over the contiguous United States. Volume 1 - Technical report

Satellite applications to aircraft communications, navigation, and surveillance over US including synthesized satellite network and aircraft equipment for air traffic contro

Leistungsbewertung von Satellitennavigation und Entwicklung des amp;quot;Safety Caseamp;quot;

Operational approval of satellite navigation applications for civil aviation exists for supplemental use in continental airspace and for primary use during oceanic en-route phases of flight for a small number of operators and in exceptional cases for Non-Precision Approach. This situation, that the operational approval does not keep pace with the technical capabilities of satellite navigation, is mainly the result of insufficient knowledge about the system´s integrity and institutional limitations including concern over single-State control, lack of "traceability" and a complete absence of binding performance guarantees. In order to achieve progress towards extending the operational approval for satellite navigation applications, for the first time an attempt is made to combine parameters describing the Required Navigation Performance and those describing the performance of satellite navigation. The established set of parameters forms the basis for an exhaustive system evaluation comprising a unique flight trial programme which involves a wide-body commercial airliner. The overall aim is to build-up confidence in the satellite navigation system´s performance, in particular, concerning integrity and continuity of service by developing a total system concept. A world-wide unique database system has been developed - following rigorous software engineering and quality assurance procedures - to contain the data recorded onboard the airliner. The subsequent data evaluation process demonstrates to what extend GPS RAIM satisfies the Required Navigation Performance for civil aviation during different phases of flight. It is demonstrated how an augmentation such as barometric-aiding can improve the system performance and can allow a wider range of operational applications. These results are the major input, via a hazard identification tree, into the GNSS Safety Case, the concept of which is developed herein. The Safety Case, incorporating a Risk Model at its core, is proposed for the first time as a methodology for an Traffic Service Provider to demonstrate that the operational use of satellite navigation can achieve its Target Level of Safety and that it can therefore be approved for operational use by Safety Regulatory Authorities. This work is the unique attempt to use a scientific-technical approach to develop a total system concept which can contribute to progressing the operational approval of satellite navigation applications in civil aviation. Although the investigations are based on applications for civil aviation, research was conducted into the requirements of maritime and terrestrial user communities and how the Safety Case concept developed in this document could be applied in the context of multi-modal transport.Anwendungen der Satellitennavigation für die Zivilluftfahrt wurden bisher als ergänzendes Navigationsmittel im kontinentalen Luftraum und als primäres für eine geringe Anzahl von Flugzeugbetreibern im ozeanischen Luftraum operationell zugelassen, in besonderen Fällen erfolgten Genehmigungen des Einsatzes als primäres Navigationssystem für Nicht-Präzisionsanflüge. Diese Situation, in der die operationelle Zulassung mit den technischen Entwicklungen nicht Schritt halten kann, ist vornehmlich die Folge des nicht ausreichenden Kenntnisstandes bezüglich der Systemintegrität und der institutionellen Einschränkungen. Im einzelnen beziehen diese sich auf die Systemkontrolle, die von einem einzelnen Staat durchgeführt wird, auf die Nichtverfügbarkeit wichtiger Systeminformationen und das Fehlen verbindlicher Garantien für die Leistungsfähigkeit des Systems. Um Fortschritt in der operationellen Zulassung von Satellitennavigationsanwendungen zu erzielen, werden in dieser Arbeit erstmalig Parameter, die die allgemeinen Anforderungen an Navigationssysteme darstellen mit denen verknüpft, die die Leistungsfähigkeit der Satellitennavigation beschreiben. Der entwickelte Parametersatz stellt die Grundlage für eine umfangreiche Systembewertung dar, welche ein einmaliges Flugversuchsprogramm mit einem Großraumflugzeug umfasst. Erklärtes Ziel ist es, zuverlässige Aussagen über die Leistungsfähigkeit, insbesondere die Integrität und die Kontinuität der Satellitennavigation, machen zu können, indem ein gesamtheilicher Systemansatz entwickelt wird. Dazu ist ein weltweit einzigartiges Datanbanksystem, das strengen Anforderungen von "Software Engineering" und Qualitätssicherung gerecht werdend, entwickelt worden, welches die Daten enthält, die an Bord des Verkehrsflugzeuges aufgezeichnet worden sind. Der sich anschließende Datenauswertungsprozess zeigt, in wieweit GPS RAIM den Anforderungen der Zivilluftfahrt an ein Navigationssystem gerecht werden kann, das für die unterschiedlichen Phasen eines Fluges eingesetzt werden soll. Es wird aufgezeigt, wie die Leistungsfähigkeit des Navigationssystems durch eine Augmentierung, z.B. mit Hilfe der Information eines barometrischen Höhenmessers, gesteigert wird, und damit das operationelle Einsatzspektrum erweitert werden kann. Die erzielten Ergebnisse fließen über einen Fehleridentifikationsbaum in das in dieser Arbeit entwickelte Konzept des GNSS "Safety Case" ein. Der "Safety Case", der in seinem Kern auf einem Risikomodell basiert, wird erstmalig den Flugsicherungsorganisationen als eine Methode vorgeschlagen, die diese einsetzen könnnen um nachzuweisen, dass der operationelle Einsatz der Satellitennavigation die gestellten Sicherheitsanforderungen erfüllt und damit von Zulassungsbehörden genehmigt werden kann. Diese Arbeit stellt den erstmaligen Versuch dar, mit Hilfe eines technisch-wissenschaftlichen Ansatzes ein gesamtheitliches Systemkonzept zu entwickeln, das einen Beitrag zum Fortschritt in der operationellen Zulassung von Satellitennavigationsanwendungen liefern kann. Die Untersuchungen basieren auf Anwendungen für die Zivilluftfahrt. Es werden jedoch auch Nachforschungen angestellt welches die Anforderungen von maritimen und terrestrischen Nutzern sind und wie das in dieser Arbeit entwickelte Konzept des "Safety Case" in den Kontext des multi-modalen Transports übertragen werden kann

Characterization and Performance Assessment of BeiDou-2 and BeiDou-3 Satellite Group Delays

Based on one year of data, a comprehensive assessment of broadcast group delays and differential code biases (DCBs) from network solutions is presented for all open BeiDou signals. Daily DCB estimates exhibit a precision of 0.1 ns, which also places a limit on long-term variations of the satellite group delays. On the other hand, the estimated DCBs show a notable dependence on the employed receivers, which causes inconsistencies at the few-nanosecond level between BeiDou-2 and BeiDou-3 satellites. Systematic satellite-specific offsets can likewise be identified in broadcast group delay values and clock offsets. These constitute the dominant contribution of the signal-in-space range error (SISRE) budget and are a limiting factor for single point positioning and timing. Use of the modernized B1C/B2a signals is therefore recommended instead of B1I/B3I. This offers a SISRE reduction from about 0.6 m to 0.45 m and also improves the consistency of precise clock and bias products derived from heterogeneous receiver networks

DGNSS Cooperative Positioning in Mobile Smart Devices: A Proof of Concept

Global Navigation Satellite System (GNSS) constitutes the foremost provider for geo-localization in a growing number of consumer-grade applications and services supporting urban mobility. Therefore, low-cost and ultra-low-cost, embedded GNSS receivers have become ubiquitous in mobile devices such as smartphones and consumer electronics to a large extent. However, limited sky visibility and multipath scattering induced in urban areas hinder positioning and navigation capabilities, thus threatening the quality of position estimates. This work leverages the availability of raw GNSS measurements in ultralow-cost smartphone chipsets and the ubiquitous connectivity provided by modern, low-latency network infrastructures to enable a Cooperative Positioning (CP) framework. A Proof Of Concept is presented that aims at demonstrating the feasibility of a GNSS-only CP among networked smartphones embedding ultra-low-cost GNSS receivers. The test campaign presented in this study assessed the feasibility of a client-server approach over 4G/LTE network connectivity. Results demonstrated an overall service availability above 80%, and an average accuracy improvement over the 40% w.r.t. to the GNSS standalone solution

AAS/GSFC 13th International Symposium on Space Flight Dynamics

This conference proceedings preprint includes papers and abstracts presented at the 13th International Symposium on Space Flight Dynamics. Cosponsored by American Astronautical Society and the Guidance, Navigation and Control Center of the Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude dynamics; and mission design

New on-board multipurpose architecture integrating modern estimation techniques for generalized GNSS based autonomous orbit navigation

This dissertation investigates a novel Multipurpose Earth Orbit Navigation System (MEONS) architecture aiming at providing a generalized GNSS based spacecraft orbit estimation kernel matching the modern navigation instance of enhanced flexibility with respect to multiple Space Service Volume (SSV) applications (Precise Orbit Determination for Earth Observation satellite, Low Thrust Low to High Autonomous Orbit Rising, formation flying relative navigation, Small Satellite Autonomous Orbit Acquisition). The possibility to address theoretical and operational solutions within a unified framework is a foundamental step for the implementation of a reusable and configurable high performance navigation capability on next generation platforms

Orbit determination of Sentinel-6A using the Galileo high accuracy service test signal

The High Accuracy Service (HAS) is an upcoming addition to the Galileo service portfolio that offers free correction data for precise point positioning in real-time. Beyond terrestrial and aeronautical applications, precise orbit determination (POD) of satellites in low Earth orbit (LEO) has been proposed as a potential use case for HAS corrections in view of their global availability. Based on HAS data collected during a test campaign in September 2021, the benefit of HAS corrections is assessed for real-time, onboard navigation as well as near real-time POD on the ground using GNSS observations of the Sentinel-6A LEO satellite. Compared to real-time POD using only broadcast ephemerides, performance improvements of about 40%, 10%, and 5% in terms of 3D position error can already be achieved for GPS-only, GPS + Galileo, and Galileo-only navigation. While Galileo processing benefits only moderately from the HAS correction data during the early tests in view of an already excellent Open Service performance, their use is highly advantageous for GPS processing and enables dual-constellation navigation with balanced contributions of both GNSSs for improved robustness. For near real-time offline POD, HAS corrections offer reduced latency or accuracy compared to established ultra-rapid GNSS orbit and clock products as well as independence from external sources