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The GPS Assimilator: a Method for Upgrading Existing GPS User Equipment to Improve Accuracy, Robustness, and Resistance to Spoofing
Preprint of the 2010 ION GNSS Conference
Portland, OR, September 21â24, 2010A conceptual method is presented for upgrading existing GPS user equipment, without requiring hardware or software modifications to the equipment, to improve the equipmentâs position, velocity, and time (PVT) accuracy, to increase its PVT robustness in weak-signal or jammed environments, and to protect the equipment from counterfeit GPS signals (GPS spoofing). The method is embodied in a device called the GPS Assimilator that couples to the radio frequency (RF) input of an existing GPS receiver. The Assimilator extracts navigation and timing information from RF signals in its environmentâincluding non-GNSS signalsâand from direct baseband aiding provided, for example, by an inertial navigation system, a
frequency reference, or the GPS user. The Assimilator optimally fuses the collective navigation and timing information to produce a PVT solution which, by virtue of the diverse navigation and timing sources on which it is based, is highly accurate and inherently robust to GPS signal obstruction and jamming. The Assimilator embeds the PVT solution in a synthesized set of GPS signals and injects
these into the RF input of a target GPS receiver for which an accurate and robust PVT solution is desired. A prototype software-defined Assimilator device is presented with three example applications.Aerospace Engineerin
From the Ashes of Glory: The Rise and Fall of Jackson Ward
This paper uses primary and secondary research to analyze the political, economic, and social factors that created Jackson Ward as a separate, alternative space for black Richmonders. In addition, this paper analyzes the key institutions that made up Jackson Ward as well as the reasons surrounding its decline following desegregation
Linked Data - the story so far
The term âLinked Dataâ refers to a set of best practices for publishing and connecting structured data on the Web. These best practices have been adopted by an increasing number of data providers over the last three years, leading to the creation of a global data space containing billions of assertionsâ the Web of Data. In this article, the authors present the concept and technical principles of Linked Data, and situate these within the broader context of related technological developments. They describe progress to date in publishing Linked Data on the Web, review applications that have been developed to exploit the Web of Data, and map out a research agenda for the Linked Data community as it moves forward
Multivariate searches for single top quark production with the D0 detector
We present a search for electroweak production of single top quarks in the
s-channel (p-pbar -> t bbar + X) and t-channel (p-pbar -> tq bbar + X) modes.
We have analyzed 230 pb^(-1) of data collected with the D0 detector at the
Fermilab Tevatron collider at a center-of-mass energy of sqrt(s) = 1.96 TeV.
Two separate analysis methods are used: neural networks and a cut-based
analysis. No evidence for a single top quark signal is found. We set 95%
confidence level upper limits on the production cross sections using Bayesian
statistics, based on event counts and binned likelihoods formed from the neural
network output. The limits from the neural network (cut-based) analysis are 6.4
pb (10.6 pb) in the s-channel and 5.0 pb (11.3 pb) in the t-channel.Comment: submitted to Phys. Rev. D, Fermilab preprint Fermilab-Pub-06/069-
Continuous maintenance and the future â Foundations and technological challenges
High value and long life products require continuous maintenance throughout their life cycle to achieve required performance with optimum through-life cost. This paper presents foundations and technologies required to offer the maintenance service. Component and system level degradation science, assessment and modelling along with life cycle âbig dataâ analytics are the two most important knowledge and skill base required for the continuous maintenance. Advanced computing and visualisation technologies will improve efficiency of the maintenance and reduce through-life cost of the product. Future of continuous maintenance within the Industry 4.0 context also identifies the role of IoT, standards and cyber security
On the Security of the Automatic Dependent Surveillance-Broadcast Protocol
Automatic dependent surveillance-broadcast (ADS-B) is the communications
protocol currently being rolled out as part of next generation air
transportation systems. As the heart of modern air traffic control, it will
play an essential role in the protection of two billion passengers per year,
besides being crucial to many other interest groups in aviation. The inherent
lack of security measures in the ADS-B protocol has long been a topic in both
the aviation circles and in the academic community. Due to recently published
proof-of-concept attacks, the topic is becoming ever more pressing, especially
with the deadline for mandatory implementation in most airspaces fast
approaching.
This survey first summarizes the attacks and problems that have been reported
in relation to ADS-B security. Thereafter, it surveys both the theoretical and
practical efforts which have been previously conducted concerning these issues,
including possible countermeasures. In addition, the survey seeks to go beyond
the current state of the art and gives a detailed assessment of security
measures which have been developed more generally for related wireless networks
such as sensor networks and vehicular ad hoc networks, including a taxonomy of
all considered approaches.Comment: Survey, 22 Pages, 21 Figure
Architecture, Protocols, and Algorithms for Location-Aware Services in Beyond 5G Networks
The automotive and railway industries are rapidly transforming with a strong
drive towards automation and digitalization, with the goal of increased
convenience, safety, efficiency, and sustainability. Since assisted and fully
automated automotive and train transport services increasingly rely on
vehicle-to-everything communications, and high-accuracy real-time positioning,
it is necessary to continuously maintain high-accuracy localization, even in
occlusion scenes such as tunnels, urban canyons, or areas covered by dense
foliage. In this paper, we review the 5G positioning framework of the 3rd
Generation Partnership Project in terms of methods and architecture and propose
enhancements to meet the stringent requirements imposed by the transport
industry. In particular, we highlight the benefit of fusing cellular and sensor
measurements and discuss required architecture and protocol support for
achieving this at the network side. We also propose a positioning framework to
fuse cellular network measurements with measurements by onboard sensors. We
illustrate the viability of the proposed fusion-based positioning approach
using a numerical example.Comment: 7 pages, 5 figures, accepted for publication in IEEE Communications
Standards Magazin
Zimbabwe and political transition
This paper looks at the factors which helped ZANU-PF as a former liberation movement retain power and lead to a one-party dominant state. It also explores the extent to which ZANU-PF is adapting to democratic politics and multiparty elections
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