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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

SINGLE EVENT UPSETS IN SPACECRAFT DIGITAL SYSTEMS

Lewkowicz, Paul E., Richter, Linda Jean 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 1984 / Riviera Hotel, Las Vegas, Nevada / This paper describes the physical environment that can result in random bit changes in space-borne memory systems. The impact of bit flips in digital telemetry systems is emphasized, with special attention paid to software requirements for protection from single event upset (SEU) effects. Some observations on incidence rates are presented along with an outline of hardware and software methods that can be taken to prevent future SEU problems. Several conclusions are drawn about strategies for preventing data corruption on the next generation of satellites in the presence of SEU-inducing particles.
2

AN XML-DRIVEN ARCHITECTURE FOR INSTRUMENTATION COCKPIT DISPLAY SYSTEMS

Portnoy, Michael, Berdugo, Albert 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Designing and implementing an instrumentation cockpit display system presents many unique challenges. The system must be easy to use, yet highly customizable. Typically, these systems require an experienced programmer to create graphical display screens. Furthermore, most current display systems do not provide for bi-directional communication between the instrumentation system and the display system. This paper discusses an architecture that addresses these issues and other common problems with cockpit displays. This system captures data from the instrumentation system, displays parameters, and returns calculated parameters and status information regarding pilot actions to the instrumentation system. Unlike traditional systems, the configuration of the graphical presentation of the cockpit display can be done by a non-programmer. All communication between the instrumentation system and the cockpit display system is done transparently using XML. The usage of XML in this system facilitates real-time form previewing, cross-platform compatibility, and seamless transitions between project management, graphical configuration, and engineering unit conversions.
3

ADVANCED RANGE TELEMETRY DYNAMIC MEASUREMENT LISTS

Luten, Robert H., Diekmann, Vernon 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A typical telemetry system for aircraft flight-testing transmits one or several data streams to the ground for real-time display and analysis, and also records the same stream onboard for later playback. During test operations, only a fraction of the available data is used at any given time for real-time display or analysis. More efficient use of the RF channel could be realized if only the data needed for the current test point is transmitted, rather than the entirety of the data. Intelligent selection of a subset of the data stream can provide large reductions in the required telemetry downlink bandwidth. As one of the Advanced Range Telemetry (ARTM) On-Board Data Management (OBDM) initiatives, a prototype on-board data selection subsystem is being developed and demonstrated. The demonstration utilizes COTS telemetry workstations to the maximum extent possible and includes “plug-in” data requestor, selection, and server components to implement the added DML functionality. A significant objective of the OBDM/DML project will be to validate RF channel models to help minimize the amount of flight-testing necessary to validate the DML concept. This paper will discuss the OBDM/DML architecture, integration of several custom components with the COTS portions of the ARTM “test bench”, and the current status of the OBDM/DML development and test program.
4

On-board processing with AI for more autonomous and capable satellite systems

Lund, Tamina January 2022 (has links)
While the use of Artificial Intelligence (AI) has faced a sharp up-rise in popularity in ground-based industries, such as for autonomous navigation in the automotive industry and predictive maintenance in manufacturing processes, it is yet only rarely used in space industry. Hence, this thesis aims to investigate the possibilities of using AI for processing on-board Earth-orbiting satellites while in orbit. In a first step, the interests and trends of deploying AI on-board satellites are studied, followed by challenges that are hindering the progression of its development. In a second step, five potential on-board applications are selected for investigation of their overall relevance to space industry, as well as their benefits compared to traditional approaches. Out of these, the possibility of using AI for predicting the degradation of batteries is selected for further study, as it shows the highest potential. Today’s approaches for monitoring battery degradation on satellites are highly insufficient and there is a great demand for a new approach. Several AI-based methods have been proposed in literature, but only rarely for processing directly on-board. Thus, I investigate the feasibility of adopting such an algorithm for on-board use, including an evaluation of the suitability of different algorithms, as well as the choice of input parameters and training data. I find that the use of AI could highly improve various aspects of satellite performance both on a platform and a payload level, by making them more efficient, but also more capable, such as for in-orbit battery prediction on-board. However, its implementation is still heavily hampered by the lack of validation and verification standards for AI in space, along with limitations imposed by the space environment, restricting the satellite design. In the investigation of using AI for on-board battery prediction, I find that this would be a suitable application for constellation satellites in LEO, in particular for prolonging their operations beyond their planned lifetime while still being able to ensure safe decommissioning. I estimate that this would lead to a yearly minimal average saved satellite replacement cost of $ 22 million in a constellation with 500 satellites, assuming an extension of the satellite lifetime from 7 to 7.5 years when using this application. Based on references in literature, I find that using a Long Short-Term Memory (LSTM) algorithm could make the most intricate predictions, whereas a Gated Recurrent Unit (GRU) algorithm would be less processing-heavy at the cost of a loss in accuracy. Training needs to be done on ground, either on telemetry data from past, similar missions or on synthetic data from simulations. Its implementation needs to be investigated in future research, including the selection of a suitable framework, but also benchmarking for evaluating the necessary processing power and memory space.
5

On-Board Data Processing and Filtering

Faber, Marc 10 1900 (has links)
ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / One of the requirements resulting from mounting pressure on flight test schedules is the reduction of time needed for data analysis, in pursuit of shorter test cycles. This requirement has ramifications such as the demand for record and processing of not just raw measurement data but also of data converted to engineering units in real time, as well as for an optimized use of the bandwidth available for telemetry downlink and ultimately for shortening the duration of procedures intended to disseminate pre-selected recorded data among different analysis groups on ground. A promising way to successfully address these needs consists in implementing more CPU-intelligence and processing power directly on the on-board flight test equipment. This provides the ability to process complex data in real time. For instance, data acquired at different hardware interfaces (which may be compliant with different standards) can be directly converted to more easy-to-handle engineering units. This leads to a faster extraction and analysis of the actual data contents of the on-board signals and busses. Another central goal is the efficient use of the available bandwidth for telemetry. Real-time data reduction via intelligent filtering is one approach to achieve this challenging objective. The data filtering process should be performed simultaneously on an all-data-capture recording and the user should be able to easily select the interesting data without building PCM formats on board nor to carry out decommutation on ground. This data selection should be as easy as possible for the user, and the on-board FTI devices should generate a seamless and transparent data transmission, making a quick data analysis viable. On-board data processing and filtering has the potential to become the future main path to handle the challenge of FTI data acquisition and analysis in a more comfortable and effective way.
6

Study on the Simulation and Analysis of an FH/FDMA OBP Satellite Based Mobile Communication System Under Critical Channel Impairment

Orra, Mike 07 September 2010 (has links)
No description available.
7

Model lineárního transpondéru / Linear Transponder Model

Pospíšil, Miroslav January 2010 (has links)
This master’s thesis deals with satellite transponders. Firstly, satellite communication basics, satellite services definitions, frequency bands and satellite orbits are investigated. The second chapter forms the satellite transponders analysis. The transparent transponder and the transponder with on-board processing are described. Finally, a transponder model is designed and simulated in communication chain.

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