Satellite Navigation for the Age of Autonomy

Global Navigation Satellite Systems (GNSS) brought navigation to the masses. Coupled with smartphones, the blue dot in the palm of our hands has forever changed the way we interact with the world. Looking forward, cyber-physical systems such as self-driving cars and aerial mobility are pushing the limits of what localization technologies including GNSS can provide. This autonomous revolution requires a solution that supports safety-critical operation, centimeter positioning, and cyber-security for millions of users. To meet these demands, we propose a navigation service from Low Earth Orbiting (LEO) satellites which deliver precision in-part through faster motion, higher power signals for added robustness to interference, constellation autonomous integrity monitoring for integrity, and encryption / authentication for resistance to spoofing attacks. This paradigm is enabled by the 'New Space' movement, where highly capable satellites and components are now built on assembly lines and launch costs have decreased by more than tenfold. Such a ubiquitous positioning service enables a consistent and secure standard where trustworthy information can be validated and shared, extending the electronic horizon from sensor line of sight to an entire city. This enables the situational awareness needed for true safe operation to support autonomy at scale.Comment: 11 pages, 8 figures, 2020 IEEE/ION Position, Location and Navigation Symposium (PLANS

Space shuttle navigation analysis. Volume 1: GPS aided navigation

Analytical studies related to space shuttle navigation are presented. Studies related to the addition of NAVSTAR Global Positioning System user equipment to the shuttle avionics suite are presented. The GPS studies center about navigation accuracy covariance analyses for both developmental and operational phases of GPS, as well as for various orbiter mission phases

Advanced tracking systems design and analysis

The results of an assessment of several types of high-accuracy tracking systems proposed to track the spacecraft in the National Aeronautics and Space Administration (NASA) Advanced Tracking and Data Relay Satellite System (ATDRSS) are summarized. Tracking systems based on the use of interferometry and ranging are investigated. For each system, the top-level system design and operations concept are provided. A comparative system assessment is presented in terms of orbit determination performance, ATDRSS impacts, life-cycle cost, and technological risk

Autonomous integrated GPS/INS navigation experiment for OMV. Phase 1: Feasibility study

The phase 1 research focused on the experiment definition. A tightly integrated Global Positioning System/Inertial Navigation System (GPS/INS) navigation filter design was analyzed and was shown, via detailed computer simulation, to provide precise position, velocity, and attitude (alignment) data to support navigation and attitude control requirements of future NASA missions. The application of the integrated filter was also shown to provide the opportunity to calibrate inertial instrument errors which is particularly useful in reducing INS error growth during times of GPS outages. While the Orbital Maneuvering Vehicle (OMV) provides a good target platform for demonstration and for possible flight implementation to provide improved capability, a successful proof-of-concept ground demonstration can be obtained using any simulated mission scenario data, such as Space Transfer Vehicle, Shuttle-C, Space Station

Visibility of LEO satellites under different ground network distributions

The Low Earth Orbit (LEO) satellites have shown various benefits in augmenting the Positioning, Navigation and Timing (PNT) service based on Global Navigation Satellite Systems (GNSSs). The higher number of LEO satellites and their much smaller footprints than those of the GNSS satellites motivate studies of the ground tracking network design to pursue higher visibilities to LEO satellites. This contribution proposes an algorithm, called here ‘MaxVis’ to select network stations for LEO satellites of different inclinations and altitudes. The goal is to increase the general visibility and shorten the visibility gaps of LEO satellite that can be observed from the entire ground network, i.e., when at least one of the network stations are visible to the satellite. A parameter can be set to balance the priority of the two objectives. It was found that LEO satellites with high altitudes and low inclinations tend to deliver high visibility. With only the polar regions excluded from the design area for demonstration purposes, the general visibility could reach above 98% with less than 30 stations when the LEO satellite has an altitude of 1200 km and an inclination of 50 degrees. The visibility could be significantly reduced when island areas are excluded from the design area

Standalone and RTK GNSS on 30,000 km of North American Highways

There is a growing need for vehicle positioning information to support Advanced Driver Assistance Systems (ADAS), Connectivity (V2X), and Automated Driving (AD) features. These range from a need for road determination (<5 meters), lane determination (<1.5 meters), and determining where the vehicle is within the lane (<0.3 meters). This work examines the performance of Global Navigation Satellite Systems (GNSS) on 30,000 km of North American highways to better understand the automotive positioning needs it meets today and what might be possible in the near future with wide area GNSS correction services and multi-frequency receivers. This includes data from a representative automotive production GNSS used primarily for turn-by-turn navigation as well as an Inertial Navigation System which couples two survey grade GNSS receivers with a tactical grade Inertial Measurement Unit (IMU) to act as ground truth. The latter utilized networked Real-Time Kinematic (RTK) GNSS corrections delivered over a cellular modem in real-time. We assess on-road GNSS accuracy, availability, and continuity. Availability and continuity are broken down in terms of satellite visibility, satellite geometry, position type (RTK fixed, RTK float, or standard positioning), and RTK correction latency over the network. Results show that current automotive solutions are best suited to meet road determination requirements at 98% availability but are less suitable for lane determination at 57%. Multi-frequency receivers with RTK corrections were found more capable with road determination at 99.5%, lane determination at 98%, and highway-level lane departure protection at 91%.Comment: Accepted for the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019), Miami, Florida, September 201

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