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Jul 11, 2010
07/10
by
Chi, A. R.; Wardrip, S. C
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The OMEGA transmissions from North Dakota on 13.10 and 12.85 kHz were monitored at several sites using a recently developed OMEGA timing receiver specifically designed for this purpose. The experiments were conducted at Goddard Space Flight Center, Greenbelt, Maryland; U.S. Naval Observatory, Washington, D.C.; and at the NASA tracking station, Rosman, North Carolina. Results show that cycle identification of the two carrier frequencies was made at each test site, thus, coarse time (76...
Topics: ATOMIC CLOCKS, AUTOMATIC CONTROL, TIME MEASUREMENT, UNIVERSAL TIME, LORAN C, MINICOMPUTERS,...
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200
Jul 23, 2010
07/10
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Cohen, Herbert A
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In this overview, on the possible uses of high power beams aboard the space station, the advantages of the space station as compared to previous space vehicles are considered along with the kind of intense beams that could be generated, the possible scientific uses of these beams and associated problems. This order was delibrately chosen to emphasize that the means, that is, the high power particle ejection devices, will lead towards the possible ends, scientific measurements in the Earth's...
Topics: AIR NAVIGATION, LORAN C, MICROCOMPUTERS, RECEIVERS, SOFTWARE ENGINEERING, ARRIVALS, ERRORS, GROUND...
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136
Jul 11, 2010
07/10
by
Davis, D. D
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Comparison of crystal oscillators to the rubidium stabilized color burst is made easy and inexpensive by use of the color bar phase meter. Required equipment consists of an unmodified color TV receiver, a color bar synthesizer and a stop watch (a wrist watch or clock with sweep second hand may be used with reduced precision). Measurement precision of 1 x 10 to the minus 10th power can be realized in measurement times of less than two minutes. If the color bar synthesizer were commercially...
Topics: CLOCKS, UNITED STATES, OBSERVATORIES, SYNCHRONISM, TIME, AUSTRALIA, LORAN C, SATELLITE TRACKING,...
Detailed cost calculations for implementation at a "basic" level of the new standards for school media programs of the American Library Association are presented. (SP)
Topics: ERIC Archive, Educational Technology, Program Costs, Standards, Twyford, Loran C., Jr.
To make comparisons between school districts and to establish standards for educational communications programs, each Director of Educational Communications in each school district in New York State submitted data about his educational communication program. In summary tables for each school district, the following data are presented: the number of students enrolled, teachers, educational communications staff (professional and non-teaching), projectors (16mm, filmstrip, overhead, opaque, micro,...
Topics: ERIC Archive, Audio Equipment, Audiovisual Aids, Audiovisual Communications, Audiovisual...
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391
Jul 23, 2010
07/10
by
Griffin, Charles F.; James, Arthur M
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The damage-tolerance characteristics of high strain-to-failure graphite fibers and toughened resins were evaluated. Test results show that conventional fuel tank sealing techniques are applicable to composite structures. Techniques were developed to prevent fuel leaks due to low-energy impact damage. For wing panels subjected to swept stroke lightning strikes, a surface protection of graphite/aluminum wire fabric and a fastener treatment proved effective in eliminating internal sparking and...
Topics: ICE FORMATION, INSTRUMENT APPROACH, LORAN C, SPEECH RECOGNITION, AIR NAVIGATION, AIR TRAFFIC...
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210
Jul 12, 2010
07/10
by
Hanel, R. A
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In the last dozen years spaceborne Fourier transform spectrometers have obtained infrared emission spectra of Earth, Mars, Jupiter, Saturn and Titan as well as of the Galilean and other Saturnian satellites and Saturn's rings. Intercomparisons of the properties of planetary atmospheres and of the characteristics of solid surfaces are now feasible. The principles of remotely sensing the environment on a planetary body are dicussed. Special consideration is given to the most recent results...
Topics: FREQUENCY STANDARDS, TABLES (DATA), INDIA, SYMPHONIE SATELLITES, TIME SIGNALS, VERY LOW...
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500
Jul 23, 2010
07/10
by
Lawrence, Charle
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There is an increasing need to develop Parameter Identification methods for improving structural dynamic models, based on the inability of engineers to produce mathematical models which correlate with experimental data. This research explores the efficiency of combining Component Mode Synthesis (substructuring) methods with Parameter Identification procedures in order to improve analytical modeling of structural components and their connections. Improvements are computed in terms of physical...
Topics: AIR NAVIGATION, PROBABILITY THEORY, SYSTEM FAILURES, AVIONICS, FLIGHT CONTROL, RELIABILITY...
The multisensor navigation systems research evolved from the availability of several stand alone navigation systems and the growing concern for aircraft navigation reliability and safety. The intent is to develop a multisensor navigation system during the next decade that will be capable of providing reliable aircraft position data. These data will then be transmitted directly, or by satellite, to surveillance centers to aid the process of air traffic flow control. In order to satisfy the...
Topics: NASA Technical Reports Server (NTRS), AIR TRAFFIC CONTROL, ALTIMETERS, GLOBAL POSITIONING SYSTEM,...
The software package developed for the KIM-1 Micro-System and the Mini-L PLL receiver to simplify taking flight test data is described along with the address and data bus buffers used in the KIM-1 Micro-system. The interface hardware and timing are also presented to describe completely the software programs.
Topics: NASA Technical Reports Server (NTRS), BUFFER STORAGE, COMPUTER SYSTEMS PROGRAMS, FLIGHT TESTS,...
The power supply unit was developed to serve as the power source for a loran-C receiver. The power supply can be connected directly to the aircraft's electrical system, and is compatible with either 14 or 28 volt electrical systems. Design specifications are presented for the unit along with a description of the circuit design.
Topics: NASA Technical Reports Server (NTRS), AVIONICS, DC 3 AIRCRAFT, ELECTRIC POTENTIAL, ELECTRONIC...
A flight evaluation of LORAN C as a supplement to existing navigation aids for general aviation aircraft, particularly in mountainous regions of the United States and where VOR coverage is limited was conducted. Flights, initiated in the summer months, extend through four seasons and practically all weather conditions typical of northeastern U.S. operations. Assessment of all the data available indicates that LORAN C signals are suitable as a means of navigation during enroute, terminal and...
Topics: NASA Technical Reports Server (NTRS), GENERAL AVIATION AIRCRAFT, LORAN C, MOUNTAINS, NAVIGATION...
The latest RF front end built by Burhans (Mini-L-82) was successfully interfaced to the Ohio University LORAN-C receiver. In order for the front end to operate optimally, modifications were made to existing automatic gain control (AGC) circuitry already developed for the Ohio University LORAN-C receiver. The hardware modifications to the AGC and other interface circuitry, as well as some preliminary results are discussed.
Topics: NASA Technical Reports Server (NTRS), AUTOMATIC GAIN CONTROL, INTERFACES, LORAN C, CIRCUITS,...
An indepth examination of the timing and telemetry in just one spacecraft points out the genesis of various types of timing errors and serves as a guide in the design of future timing/telemetry systems. The principal sources of timing errors are examined carefully and are described in detail. Estimates of these errors are also made and presented. It is found that the timing errors within the telemetry system are larger than the total timing errors resulting from all other sources.
Topics: NASA Technical Reports Server (NTRS), ERROR ANALYSIS, SPACECRAFT COMMUNICATION, TELEMETRY, TIME...
Development of a low cost Loran C receiver for general aviation use is discussed. The preparation and procedure of a flight test conducted with a receiver design which utilizes a phase locked loop oscillator to track the Loran C signals is described. It is indicated that such a receiver is a viable alternative for future work in developing a low cost Loran-C navigator.
Topics: NASA Technical Reports Server (NTRS), DATA ACQUISITION, FLIGHT TESTS, LORAN C, RADAR RECEIVERS,...
Three projects sponsored by the Joint University Program at MIT are summarized. Two projects were focussed on the potential application of Loran-C in flying nonprecision approaches to general aviation runways, and the third project involved research on aircraft icing. In one Loran-C project, Aircraft Approach Guidance Using Relative Loran-C Navigation, the concept was flight tested. It used the difference in TD's from those of the touchdown point to simplify and speed navigation computer...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AIRBORNE RADAR APPROACH, AIRCRAFT GUIDANCE,...
The design and design data for broadband loop antenna systems are presented. An investigation of some simple systems for possible Loran C receivers which require a bandwidth of greater than 20 KHz is discussed. Designs are presented for a 60 KHz WWVB antenna, several Loran C variations, and some 1750 meter band antennas. Signals received on all these, including one airborne experiment where a Loran C receiver gave the correct time difference reading within 1 microsecond while flying on a...
Topics: NASA Technical Reports Server (NTRS), ANTENNA DESIGN, LOOP ANTENNAS, LORAN C, ANTENNA COUPLERS,...
The long term performance of the eight Loran-C chains in terms of the Coordinated Universal Time (UTC) of the U.S. Naval Observatory (USNO) and the use of the Loran-C navigation system to maintain the user's clock to a UTC scale, are examined. The atomic time (AT) scale and the UTC of several national laboratories and observatories relative to the international atomic time (TAI) are presented. In addition, typical performance of several NASA tracking station clocks, relative to the USNO master...
Topics: NASA Technical Reports Server (NTRS), LORAN C, PERFORMANCE, TIMING DEVICES, UNIVERSAL TIME, CLOCKS,...
The development of an area navigation program and the implementation of this software on a microcomputer-based Loran-C receiver to provide high-quality, practical area navigation information for general aviation are described. This software provides range and bearing angle to a selected waypoint, cross-track error, course deviation indication (CDI), ground speed, and estimated time of arrival at the waypoint. The range/bearing calculation, using an elliptical Earth model, provides very good...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, LORAN C, MICROCOMPUTERS, RECEIVERS, SOFTWARE...
The integrated avionics reliability task is an effort to build credible reliability and/or performability models for multisensor integrated navigation and flight control. The research was initiated by the reliability analysis of a multisensor navigation system consisting of the Global Positioning System (GPS), the Long Range Navigation system (Loran C), and an inertial measurement unit (IMU). Markov reliability models were developed based on system failure rates and mission time.
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AVIONICS, FLIGHT CONTROL, RELIABILITY...
During the Fall of 1987 a land mobile satellite demonstration using the MARECS B2 satellite at 26 degrees W was performed. While all the data have not been digested, some observations are in order. First, the system worked remarkably well for the margins indicated. Second, when the system worked poorly, the experimenters could almost always identify terrain or other obstacles causing blockage. Third, the forward link seems relatively more reliable than the return link, and occasional return...
Topics: NASA Technical Reports Server (NTRS), COMMUNICATION SATELLITES, MOBILE COMMUNICATION SYSTEMS,...
As of 1 Oct. 1993, the US Coast Guard (USCG) supports and operates fifteen Loran-C chains. With the introduction of the Global Positioning Systems (GPS) and the termination of the Department of Defense (DOD) overseas need for Loran-C, the USCG will cease operating the three remaining overseas chains by 31 Dec. 1994. Following this date, the USCG Loran-C system will consist of twelve chains. Since 1971, management of time synchronization of the Loran-C system has been conducted under a...
Topics: NASA Technical Reports Server (NTRS), CLOCKS, DEFENSE PROGRAM, GLOBAL POSITIONING SYSTEM, LORAN C,...
Relative comparisons of Loran-C frequency transmissions between the master station of Catanzaro (Simeri Crichi) and the X, Z slave stations of Estartit (Spain) and Lampedusa (Italy) are carrying out by the GG LORSTA monitor station of the Mediterranean Sea Loran-C chain. These comparisons are able to emphasize the relative and, under certain conditions, the absolute rate of the emitting standard frequencies of the slave stations and some relevant statistical properties of the Loran-C Method for...
Topics: NASA Technical Reports Server (NTRS), FREQUENCY STABILITY, LORAN C, NOISE SPECTRA, SIGNAL...
A digital phase-locked loop was developed and implemented for use in a low cost Loran C receiver. The digital phase-locked loop design is described and it's application to Loran C is discussed.
Topics: NASA Technical Reports Server (NTRS), DIGITAL NAVIGATION, LORAN C, TRACKING FILTERS, CMOS, LOGIC...
A display enhancement implemented on the new VDM-1 video display board installed in a LORAN-C navigation receiver is addressed. Increased character size for easier viewing of the 3.75 inch diagonal CRT display is provided.
Topics: NASA Technical Reports Server (NTRS), ALPHANUMERIC CHARACTERS, CIRCUIT BOARDS, COMPUTER GRAPHICS,...
Topics: NASA Technical Reports Server (NTRS), ATOMIC CLOCKS, CONFERENCES, FREQUENCY STANDARDS, LASER RANGE...
Time comparisons were made between cesium clocks in Yugoslavia and other cesium clocks in the country by the Laboratory of Federal Bureau of Measures and Precious Metals. Regional standard frequency and time signals dissemination is over National TV network by so called active TV system. International comparisons are performed via Loran-C system and by clock transportation. The method of calculation and approximation of the time signal propagation delays is given. Settled comparison results of...
Topics: NASA Technical Reports Server (NTRS), ATOMIC CLOCKS, CESIUM, FREQUENCY STANDARDS, LORAN C,...
The use of Loran-C during approaches to landing is investigated. The Avionics Engineering Center has evaluated such approach applications at Galion, Ohio Municipal Airport and at Mansfield, Ohio Lahm airport. Loran-C data were referenced to ground tracker data to determine that the Loran-C approach path was straight, flyable, and parallel to the runway centerline. The Loran-C operational issues that were investigated are listed.
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AIRBORNE RADAR APPROACH, FLIGHT PATHS, LORAN...
The history, equipment, and current work of the Royal Greenwich Observatory are briefly reviewed.
Topics: NASA Technical Reports Server (NTRS), LONGITUDE, OBSERVATORIES, TIME MEASUREMENT, UNIVERSAL TIME,...
The hybrid use of Loran-C with the Global Positioning System (GPS) was shown capable of providing a sole-means of enroute air radionavigation. By allowing pilots to fly direct to their destinations, use of this system is resulting in significant time savings and therefore fuel savings as well. However, a major error source limiting the accuracy of GPS is the intentional degradation of the GPS signal known as Selective Availability (SA). SA-induced position errors are highly correlated and far...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, GLOBAL POSITIONING SYSTEM, LORAN C,...
On 16 May 1974, it was announced that Loran-C was chosen as the navigation system to serve the U. S. Coastal Confluence Zone. At the present time, reliable CONUS Loran-C groundwave timing coverage extends westward only about as far as Boulder, CO. The groundwave hyperbolic and timing coverage which will result from the planned CONUS expansion are illustrated. Time frames are provided. A status report on the planned reduction in Loran-C PTTI tolerances is presented.
Topics: NASA Technical Reports Server (NTRS), INTERVALS, LORAN C, TIME MEASUREMENT, FREQUENCY STANDARDS,...
Hardware documentation is provided for the modified Loran-C timing module, which uses direct software control in determining loop sample times. Computer loading is reduced by eliminating polled operation of the timing loop.
Topics: NASA Technical Reports Server (NTRS), LOOPS, LORAN C, TIMING DEVICES, COMPUTER PROGRAMS,...
Hardware documentation is provided for the modified Loran-C timing module, which used interrupt-driven software control in determing loop sample times. Computer loading is reduced by eliminating polled operation of the timing loop.
Topics: NASA Technical Reports Server (NTRS), LOOPS, LORAN C, TIMING DEVICES, COMPUTER PROGRAMS,...
A summary of the research on air transportation is addressed including navigation; guidance, control and display concepts; and hardware, with special emphasis on applications to general aviation aircraft. Completed works and status reports are presented also included are annotated bibliographies of all published research sponsored on these grants since 1972.
Topics: NASA Technical Reports Server (NTRS), CONFERENCES, DISTRIBUTED PROCESSING, LORAN C, MICROCOMPUTERS,...
The NEMS concept and design were initiated from the need to measure and record positional and environmental information during aircraft flights of developmental science research instrumentation. The unit was designed as a stand-alone system which could serve the needs of instruments whose developmental nature did not justify the cost and complexity of including these measurements within the instrument data system. Initially, the system was comprised of a Loran-C receiver and a portable IBM...
Topics: NASA Technical Reports Server (NTRS), AIRBORNE EQUIPMENT, ENVIRONMENTAL MONITORING, NAVIGATION...
Current and future Precise Time and Time Interval (PTTI) programs at the Goddard Space Flight Center (GSFC) and the evolution of frequency and time requirements over past years within the various NASA satellite tracking networks are described. A brief history of the network development is also given.
Topics: NASA Technical Reports Server (NTRS), FREQUENCY STABILITY, LORAN C, MASERS, NASCOM NETWORK,...
The Aerospace Guidance and Metrology Center (AGMC) has the responsibility for the dissemination of Precise Time and Time Interval (PTTI) to Air Force timing systems requiring microsecond time. In order to maintain traceability to the USNO Master Clock in Washington D.C., and accomplish efficient logging of time and frequency data on individual precision clocks, a simple automatic means of acquiring precise time has been devised. The Automatic Time Interval Measurement System (ATIMS) consists of...
Topics: NASA Technical Reports Server (NTRS), ATOMIC CLOCKS, AUTOMATIC CONTROL, TIME MEASUREMENT, UNIVERSAL...
A program for an HP-25 or HP-25C hand calculator that will calculate accurate LORAN-C time differences is described and presented. The program is most useful when checking the accuracy of a LORAN-C receiver at a known latitude and longitude without the aid of an expensive computer. It can thus be used to compute time differences for known landmarks or waypoints to predict in advance the approximate readings during a navigation mission.
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, LATITUDE, LONGITUDE, LORAN C, TIME...
Very Long Baseline Interferometry (pulsars), Television relay via satellite, portable clocks, Navigation Technology Satellite, and Loran C are described and compared.
Topics: NASA Technical Reports Server (NTRS), ARTIFICIAL SATELLITES, NATURAL SATELLITES, TIME MEASUREMENT,...
Engineering performed to make LORAN-C a more useful and practical navigation system for general aviation is described. Development of new software, and implementation of this software on a (MOS6502) microcomputer to provide high quality practical area navigation information directly to the pilot and considered. Flight tests were performed specifically to examine the efficacy of this new software. Final results were exceptionally good and clearly demonstrate the merits of this new LORAN-C area...
Topics: NASA Technical Reports Server (NTRS), AREA NAVIGATION, LORAN C, MICROCOMPUTERS, COMPUTER PROGRAMS,...
A computerized human engineered inspection technique is developed for use by FAA inspectors in evaluating the pilot factors aspects of aircraft navigation systems. The short title for this project is Nav Handbook. A menu-driven checklist, computer program and data base (Human Factors Design Criteria) were developed and merged to form a self-contained, portable, human factors inspection checklist tool for use in a laboratory or field setting. The automated checklist is tailored for general...
Topics: NASA Technical Reports Server (NTRS), HUMAN FACTORS ENGINEERING, INSPECTION, NAVIGATION, PILOT...
An inexpensive data/command entry and display system is documented. This system is designed to operate in place of a separate ASC2 terminal. The software to interface this unit to the 6502 based navigation receiver is also described.
Topics: NASA Technical Reports Server (NTRS), DATA PROCESSING EQUIPMENT, DISPLAY DEVICES, LORAN C,...
Navigation, guidance, control and display concepts, and hardware, with special emphasis on applications to general aviation aircraft are discussed.
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AUTOMATIC GAIN CONTROL, DEICERS,...
The Deep Space Network (DSN), managed by the Jet Propulsion Laboratory for NASA, must maintain time and frequency within specified limits in order to accurately track the spacecraft engaged in deep space exploration. Various methods are used to coordinate the clocks among the three tracking complexes. These methods include Loran-C, TV Line 10, Very Long Baseline Interferometry (VLBI), and the Global Positioning System (GPS). Calculations are made to obtain frequency offsets and Allan variances....
Topics: NASA Technical Reports Server (NTRS), DEEP SPACE NETWORK, FREQUENCY CONTROL, FREQUENCY MEASUREMENT,...
Digital satellite communication systems require careful management of frequency stability. Historically, frequency stability has been accomplished by continuously powered, high cost, high performance reference oscillators. Today's low cost mobile satellite communication equipment must operate under wide ranging environmental conditions, stabilize quickly after application of power, and provide adequate performance margin to overcome RF link impairments unique to the land mobile environment....
Topics: NASA Technical Reports Server (NTRS), DIGITAL SYSTEMS, EARTH TERMINALS, FREQUENCY STABILITY, LORAN...
The purpose is to provide a research tool, a receiver, such that engineers interested in examining Loran-C performance, usefulness, and other properties will have a flexible, modifiable, and well-known piece of receiving hardware. The significant improvements to the Loran-C receiver are summarized.
Topics: NASA Technical Reports Server (NTRS), AIR TRANSPORTATION, EQUIPMENT SPECIFICATIONS, LORAN C,...
A Multisensor Navigation System as proposed by the Ohio University Avionics Engineering Center is illustrated. The proposed system incorporates radio (Lorac-C), satellite (Global Positioning System) and an inertial navigation system (INS). The inertial part of the system will be of a low grade since the INS will be used primarily for filtering the GPS data and for short term stability. Loran-C and GPS will be used for long term stability.
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, GLOBAL POSITIONING SYSTEM, INERTIAL...
A sole means navigation system does not only call for integrity, but also for coverage, reliability, availability and accuracy. Even though ground monitored GPS will provide integrity, availability is still not sufficient. One satellite outage can affect a large service area for several hours per day. The same holds for differential GPS; a total satellite outage cannot be corrected for. To obtain sufficient coverage, extra measurements are needed, either in the form of extra GPS satellites...
Topics: NASA Technical Reports Server (NTRS), CERTIFICATION, GLOBAL POSITIONING SYSTEM, HYBRID NAVIGATION...
Some of the practical questions that arise when one decides to use Loran-C in a time reference system are explored. An extensive effort is made to provide basic, practical information on establishing and operating a reference station. Four areas were covered: (1) the design, configuration and operational concepts which should be considered prior to establishing and operating a reference station using Loran-C, (2) the options and tradeoffs available regarding capabilities, cost, size,...
Topics: NASA Technical Reports Server (NTRS), LORAN C, REFERENCE SYSTEMS, SYSTEMS ENGINEERING, TIMING...
There were three areas of research sponsored in the Flight Transportation Lab. at MIT under the Joint University Research Program during 1986. The first was the completion of efforts investigating the possibility of using Loran-C for final approach guidance to a runway; the second is a preliminary exploration of the application of automated speech recognition in Air Traffic Control; the third is a continuation of a series of research topics into aircraft icing problems.
Topics: NASA Technical Reports Server (NTRS), ICE FORMATION, INSTRUMENT APPROACH, LORAN C, SPEECH...
