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Development of an interferometric differential global positioning system ground reference stationWaid, James D. January 1993 (has links)
No description available.
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EXTENDED RANGE COMMUNICATIONS SUPPORT FOR THE X-33Eslinger, Brian, Garza, Reynaldo 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Communications support for the X-33 requires addressing several unique challenges to meet program and range safety requirements. As an avenue to minimize costs, the program has reduced requirements to the communications system, which lowered the cost of networking the extended range. Cost trade-offs showed that by lowering the telemetry data rate from 2 Megabits per second to 1.440 Megabits per second that significant cost avoidance could be realized. Also, by adopting standard telecommunications data rate for the uplink data stream, an efficient and integrated solution for the extended range communications could be supported. Meeting the program requirements as well as range safety requirements for this effort are critical to the success of the program. This paper describes some of the important requirements driving the design of the extended range communications support and the design of the system to meet those requirements.
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GPS RECEIVER SELECTION AND TESTING FOR LAUNCH AND ORBITAL VEHICLESSchrock, Ken, Freestone, Todd, Bell, Leon 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / NASA Marshall Space Flight Center’s Bantam Robust Guidance Navigation & Control Project is investigating off the shelf navigation sensors that may be inexpensively combined into Kalman filters specifically tuned for launch and orbital vehicles. For this purpose, Marshall has purchased several GPS receivers and is evaluating them for these applications. The paper will discuss the receiver selection criteria and the test equipment used for evaluation. An overview of the analysis will be presented including the evaluation used to determine their success or failure. It will conclude with goals of the program and a recommendation for all GPS users.
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A Real-Time Bi-Directional Differential Global Positioning SystemShetty, Ranjeet S. January 2002 (has links)
No description available.
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IMPLEMENTATION OF DGPS AS A FLIGHT TEST PERFORMANCE MEASUREMENT TOOLPedroza, Albert 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The accurate determination of test aircraft position and velocity is a very strong requirement in several certification and development flight test applications. This requirement often requires availability of test ranges properly instrumented with optical or radar tracking systems, precision time for data reduction and dependency on environmental and meteorological conditions. The capabilities of GPS (Global Positioning System) technology, in terms of data accuracy, speed of data availability and reduction of test operating cost, moved Bombardier Flight Test Center to make an investment and integrate a system utilizing GPS for extensive use in flight and ground test activity. Through the use of differential GPS (DGPS) procedures, Bombardier Flight Test Center was able to implement a complete system which could provide real-time data results to a very acceptable output rate and accuracy. Furthermore, the system was capable of providing post-processed data results which greatly exceeded required output rate and accuracy. Regardless of the type of aircraft testing conducted, the real-time or post-processed data could be generated for the same test. After conducting various types of testing, Bombardier Flight Test Center has accepted the DGPS as an acceptable and proper flight and ground test measurement tool for its various aircraft test platforms.
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TECHNICAL CAPABILITIES AND RESOURCES OF THE EXTENDED TEST RANGE ALLIANCEMackall, Dale A., Sakahara, Robert D. 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Edwards Flight Test Range is a part of 20,000 square miles of DOD airspace (R-2508). A hypersonic air vehicle traveling above Mach 3 can easily exceed that airspace
within seconds. An Unpiloted Autonomous Vehicle can exceed the airspace when flying
long duration missions. To satisfy the flight-test requirements of Hypersonic Air Vehicles
and Unpiloted Autonomous Vehicles, additional airspace and extended test ranges are
required. The Air Force Flight Test Center and Dryden Flight Research Center at Edwards
Air Force Base, California have mutual goals to support these flight test programs. To
meet these goals, the Extended Test Range Alliance was formed as an engineering and
operations team to satisfy program requirements in the areas of telemetry, flight
termination, ground communications, uplink command, and differential global positioning
systems. This paper will discuss the resources and technical capabilities available through
the Extended Test Range.
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Geomorphological controls on pool formation and pool persistence in non-perennial river systemsHattingh, Keaton Jade January 2020 (has links)
>Magister Scientiae - MSc / Globally climate variability and anthropogenic effects are causing more perennial rivers to become non-perennial rivers. Non-perennial rivers are distinguished by their isolated pools which serve as refugia for aquatic organisms, water birds, and riparian vegetation. The literature on non-perennial rivers demonstrates that pools are poorly understood in terms of their location, nature, and geomorphic persistence. Therefore, this study examines the relationships between the spatial distribution, morphology, and substrate characteristics of pools in reaches of the Prins and Touws rivers in the Klein Karoo. A greater understanding of pools will facilitate better management, monitoring, and restoration strategies for pool ecology since the geomorphology of pools provides a key part of the ecological template.
Worldview-2 satellite imagery (2017) and orthorectified aerial photography (2014, 2013, and 1944) were used to assess the effects of major flooding events on pools over time. A DGPS (Differential Global Positioning System) was used to survey the pool widths, lengths, depths, and valley widths, cross-sections, and longitudinal profiles of the river. Sediment samples and Wolman pebble counts were used to assess the grain size and organic matter content of each pool in the study area. Detailed descriptions of the characteristics of each pool in terms of position in the channel, valley form, and obstruction presence and type were also assessed.
Results indicate that most of the large pools occur at bedrock outcrops of the valley margins, and smaller pools are associated with Vachellia karroo debris bar features. Larger and highly persistent pools are associated with valley confinement and smaller less persistent, scour pools occur mid-channel where the valley expands. Analysis of the results shows that the valley width is the dominant control on these forced pools. The type of obstruction also plays a role in the formation of the pool as large woody debris results in smaller pools whereas, bedrock outcrops result in larger sized pools. A significant relationship was found between the grain size and organic matter content of pools.
Aerial photography of the spatial distribution of the pools revealed that before a major flood, the pools were small and patchy, whereas afterward, they were larger and more elongated. It is suggested that at the bedrock outcrops, major scouring and eddy processes drive the formation of larger pools during large flood events, whereas pool dissection by sediment deposits prevails during intervening intermediate to low flow periods. The results are discussed in terms of the geomorphic controls (valley width, pool dimensions, morphology, substrate, and obstruction characteristics) on the formation and maintenance of pools in dryland settings. A conceptual
model is proposed to explain the geomorphic changes of the pools in the four geomorphological zones of non-perennial rivers.
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