Navigation, Guidance, Control and Dynamics Commons^™

Issue 11: Contributors, Don Flournoy

Online Journal of Space Communication

Biographical information for the Issue 11 contributors:

Daniel Butler

Don Flournoy

Scott Madry

Joseph Pelton

Application Of Net-Centric Communications For Disasters (Panel 1: First Responder), Norman Jones

Online Journal of Space Communication

Norman Jones, Transformational Communications Engineering presents: Application of Net-Centric Communications for Disasters

White Paper On Emergency Communications, Space And Advanced Communications Research Institute Space And Advanced Communications Research Institute

Online Journal of Space Communication

Prepared by the Space & Advanced Communications Research Institute (SACRI)

George Washington University

January 5, 2006

Note: This White Paper draws a number of sources including presentations at the National Conference on Emergency Communications (NCEC) held at the George Washington University on December 12-13, 2005. This conference featured some thirty different speakers selected from the federal as well as state and local governments, a wide range of industry spokespeople, several professional societies, relief organizations and NGOs, universities, and other interested parties. There were thirty different sponsors. These presentations, the attendees at this conference and the many sponsors of this event …

Issue 10: From The Guest Editors, Joseph Pelton, Neil Helm

Online Journal of Space Communication

Issue 10 introduction from the guest editors.

Euler's Three-Body Problem, Sylvio R. Bistafa

Euleriana

In physics and astronomy, Euler's three-body problem is to solve for the motion of a body that is acted upon by the gravitational field of two other bodies. This problem is named after Leonhard Euler (1707-1783), who discussed it in memoirs published in the 1760s. In these publications, Euler found that the parameter that controls the relative distances among three collinear bodies is given by a quintic equation. Later on, in 1772, Lagrange dealt with the same problem, and demonstrated that for any three masses with circular orbits, there are two special constant-pattern solutions, one where the three bodies remain …

Robust Nonlinear Tracking Control For Unmanned Aircraft In The Presence Of Wake Vortex, Petr Kazarin, Vladimir Golubev, William Mackunis, Claudia Moreno

Publications

The flight trajectory of unmanned aerial vehicles (UAVs) can be significantly affected by external disturbances such as turbulence, upstream wake vortices, or wind gusts. These effects present challenges for UAV flight safety. Hence, addressing these challenges is of critical importance for the integration of unmanned aerial systems (UAS) into the National Airspace System (NAS), especially in terminal zones. This work presents a robust nonlinear control method that has been designed to achieve roll/yaw regulation in the presence of unmodeled external disturbances and system nonlinearities. The data from NASA-conducted airport experimental measurements as well as high-fidelity Large Eddy Simulations of the …

Interior Point Optimization Of Low-Thrust Spacecraft Trajectories, Jordan D. Frederiksen

Master's Theses

Low-thrust interplanetary spacecraft trajectory optimization poses a uniquely difficult problem to solve because of the inherent nonlinearities of the dynamics and constraints as well as the large size of the search space of possible solutions. Tools currently exist that optimize low-thrust interplanetary trajectories, but these tools are rarely openly available to the public, and when they are available they require multiple interfaces between multiple different packages. The goal of this work is to present a new piece of low-thrust interplanetary spacecraft trajectory optimization software that is open-source and entirely self-contained so that more people can have access to the ability …

Envelope Analysis Of Speed-Controlled Evtol Urban Air Mobility Vehicles, David J. Thompson

Doctoral Dissertations and Master's Theses

There are many vehicles being developed which rely on electrically driven propellers/rotors for both control and propulsion. Based on these vehicles, it is hypothesized that there exists a size limit for speed-controlled propellers/rotors in terms of propeller/rotor diameter. To investigate this, a scaling method was created to allow for a vehicle to be created without being based on a specific mission or passenger/cargo requirement. Relationships were developed to size both the physical vehicle and the weight of the vehicle based on the propeller/rotor diameter. A simulation of a quadcopter was created for the vehicle and scaled with both propeller/rotor diameter …

Navigation Performance Of Line/Plane Intersection Lidar Model In Conjunction With Opportunistic Feature Tracker, Michael R. Hansen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With NASA awarding numerous contracts to build commercial lunar payload spacecraft and human lunar landers, the need for high precision navigation has increased. Traditional inertial navigation alone is not sufficient to autonomously land a vehicle on hazardous lunar terrain. Terrain relative navigation (TRN) systems have been explored in previous research that exploit camera observations of known landmarks. Such approaches require the flight electronics to correctly match features of the observed landmarks to an onboard database, in the drastically varying lighting conditions of moon. This paper explores the performance of a TRN system that does not rely on apriori landmark identification, …

Issue 9: Contributors, D. Flournoy, Randall Johnson

Online Journal of Space Communication

List of issue 9 contributors.

Gps & Galileo: Prospects For Building The Next Generation Of Global Navigation Satellite Systems, Glen Gibbons Jr.

Online Journal of Space Communication

In the next 5 to 10 years, the world will experience the emergence of a true Global Navigation Satellite System (GNSS) - a compatible and, in many respects, interoperable system of systems. The U.S. Global Positioning System, Europe's Galileo, perhaps Russia's Glonass system, and regional augmentations including the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), radiobeacon-based systems such as the U.S. Nationwide Differential GPS, and compatible commercial differential correction services will comprise this multifaceted GNSS. Common signal structures and frequency plans will enable combined user equipment that reduces the technical complexity and cost, while vastly …

New U.S. Gps Policy From A European Perspective, Martin U. Ripple, Alexis Vidal

Online Journal of Space Communication

On December 8, 2004, the President of the United States of America authorized the new U.S. Space-based Positioning, Navigation and Timing Policy. This new policy sets forth a forward-looking framework for the management of GPS and its augmentations. In particular, the new U.S. policy mentions interaction with other satellite navigation systems.

Following the establishment of a U.S.-E.U. framework agreement for cooperation between GPS and Galileo, signed on June 26, 2004, European policy makers and industrialists expected clear statements on cooperation and interoperability issues from the new U.S. GPS policy. Regrettably, the related recommendations hold short of the need for cooperation …

Receiver Performance For An Enhanced Dgps Data Channel, Gregory Johnson, Michael Kuhn, Peter F. Swaszek, Richard Hartnett, Per Enge

Online Journal of Space Communication

The Coast Guard currently operates a maritime differential GPS service consisting of two control centers and over 85 remote broadcast sites. This service broadcasts GPS correction information on marine radiobeacon frequencies to improve the accuracy and integrity of GPS. The existing system provides differential corrections over a medium frequency carrier using minimum shift keying (MSK) as the modulation method. MSK is a version of the Continuous Phase Frequency Shift Keying (CPFSK) modulation technique that is "spectrally compact," meaning that it is a narrow band modulation scheme. In a binary signaling channel, the two instantaneous frequencies for this modulation method are …

Space Based Real-Time Kinematic Gps For National Geodetic Survey Texas Height Modernization, S. D. Lyle, D. M. Mulcare

Online Journal of Space Communication

Height Modernization is a program in NOAA's National Geodetic Survey (NGS) that uses the Global Positioning System (GPS) and other new technologies to increase the accuracy of elevation measurements that comprise the vertical portion of the National Spatial Reference System (NSRS). Height Modernization Program within NGS is working with states to improve the height component of their survey control networks and related products. Texas A&M University- Corpus Christi (A&M-CC) was designated as the recipient of a grant under the Program during the most recent Congressional cycle. In order to best coordinate and manage the activities funded by the grant, A&M-CC …

Sea Surface Wave Information Using Gps Sea Reflected Signal - Wave Height, Shigeyuki Okuda, Yasuo Arai, Nobuyoshi Kouguchi

Online Journal of Space Communication

In case of positioning by GPS, the direct signal from the satellite to the receiver is ordinarily utilized, but the multipath signal is regarded as one error source that deteriorate the positioning accuracy. In this paper, we focus on characteristics of the reflected signal, and had a few simulation tests. The correlator output signals are checked out and compared to the change of wave height and the wave period.

In this paper we describe that in sufficient long wave compared with reflection area size we can measure an accurate wave height, and by pointing antenna beam center from two directions …

Moving Map And Situational Awareness Capabilities Of The Dagr, Gary L. Bachman

Online Journal of Space Communication

This paper presents an overview of the Moving Mapp and Situational Awareness capabilities of the Defense Advanced GPS Receiver (DAGR) military handheld GPS receiver (refer to Figure 1), and how these capabilities can be utilized for other applications. The paper first presents an overview of situational awareness and moving maps as provided by handheld GPS receivers, factors driving the DAGR's requirements, and the requirements themselves.

This paper presents the system design in a two-part approach corresponding to the two primary components of the system: 1) importing digital map products into the DAGR and 2) displaying moving maps and situational awareness …

Egnos Terrestrial Regional Augmentation Networks Based On Ais For River Information Services, M. Jandrisits, J. C. De Mateo, G. Abwerzger

Online Journal of Space Communication

Within the ESA Advanced Research Telecommunications program ARTES-5, the project GALEWAT (Galileo and EGNOS for Waterway Transport) aims at introducing EGNOS into River Information Services (RIS) through the Automatic Identification System (AIS), a link that is mandatory for seagoing vessels above 300 GT.

The GALEWAT project comprises several phases: During the initial definition phase, the system architecture and user equipment have been defined in line with standards and international recommendations. This phase was followed by the implementation phase, aiming at developing and setting up the equipment. Finally, the project will be completed by an extensive demonstration phase, which is currently …

Geosynchronous Satellite Use Of Gps, Jennifer L. Ruiz, Charles H. Frey

Online Journal of Space Communication

The purpose of this study was to determine the accuracy of GPS use for a geosynchronous (GEO) satellite. Current missions at GEO altitude mainly use traditional ranging for orbit determination. With changing mission requirements and the increase in the number of GEO missions, utilizing GPS signals is becoming an increasingly attractive alternative for position and timing determination. A previous ION paper discusses the use of GPS data for a particular geosynchronous satellite mission and is included here as a reference. GPS use at GEO is primarily limited by the availability of the spillover from the GPS earth coverage signal. The …

Galileo In Bavariansky - Network Of Excellence In Satellite Navigation, Bärbel Deisting

Online Journal of Space Communication

The building up of the European satellite navigation system Galileo with its new services, the guaranteed reliability and continuity as well as the interoperable and complementary relation to GPS is expected to open new markets for satellite navigation applications all over the world. Many sectors will benefit from Galileo as the range of application is varied and an exponential grow is being expected for fields related to the development of satellite navigation.

During the last years several examinations dealing with satellite navigation sector in Bavaria have been carried out. The analyses revealed that satellite navigation signals serve as basis for …

Sensing Ocean, Ice And Land Reflected Signalsfrom Space: Results From The Uk-Dmc Gps Reflectometry Experiment, Scott Gleason, Mounir Adjrad, Martin Unwin

Online Journal of Space Communication

The use of Global Navigation Satellite System (GNSS) signals reflected from the Earth's surface has progressed from its beginnings in the early 1990's to a demonstrated practical linkage of measurements to geophysical characteristics of ocean, ice and land surfaces.

A pioneering space-based experiment was carried on the UK-DMC satellite launched in September of 2003. The GPS receiver on the satellite was modified to accommodate a downward (nadir) pointing medium gain antenna and to send sampled IF data to a solid-state data recorder [1]. Since its launch it has been successfully used to target and detect specular reflections of GPS signals …