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Made in 1970, this U.S. Navy film presents the mission of the U.S. Naval Observatory in context of the era of space exploration, the creation of the atomic clock, and the need to have very precise measurements of time and space for scientific and defense purposes. The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation and Timing (PNT) for the United States Navy and the United States...
Topics: Periscope Film, Stock Footage, U.S. Navy, Naval Observatory, Washington, Master Clock, Ephemeris...
679
679
Jul 23, 2010
07/10
by
Poe, C. C., Jr.; Illg, W
texts
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The National Aeronautics and Space Administration is developing graphite/epoxy filament-wound cases (FWC) for the solid rocket motors of the Space Shuttle. The membrane region is about 36 mm thick. A study was made to determine the reduction in strength of the FWC due to accidental damage caused by low-velocity impacts. Two 76.2 cm diameter by 30.5 cm long cylinders were impacted every 5 cm of circumference with 1.27 cm radius impacters of various mass. The impacters represented tools and...
Topics: AIR TRANSPORTATION, EQUIPMENT SPECIFICATIONS, LORAN C, RECEIVERS, DISPLAY DEVICES, MULTIPLEXING,...
500
500
Jul 23, 2010
07/10
by
Lawrence, Charle
texts
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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...
420
420
Jul 11, 2010
07/10
by
Proverbio, E.; Quesada, V.; Simoncini, A
texts
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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: CLOCKS, DEEP SPACE NETWORK, RADIO INTERFEROMETERS, SYNCHRONISM, DATA TRANSMISSION, LORAN C, RADIO...
391
391
Jul 23, 2010
07/10
by
Griffin, Charles F.; James, Arthur M
texts
eye 391
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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...
344
344
Jul 12, 2010
07/10
by
Walls, F. L.; Howe, D. A
texts
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The timekeeping ability of a prototype passive hydrogen maser which is a factor of 5 smaller in size, weight, and cost than any previously designed, was compared to UTC (NBS) based on 10 cesium frequency standards including a large primary standard, NBS-4. The frequency of the prototype was monitored as a function of source pressure, cavity temperature, microwave power, modulation width, and magnetic field. Based on these measurements, a frequency stability of better than 6 x 10 to the -15...
Topics: FREQUENCY STABILITY, PRECISION, LORAN C, MASERS, NASCOM NETWORK, SATELLITE NETWORKS, STDN...
320
320
Jul 11, 2010
07/10
by
Chi, A. R.; Wardrip, S. C
texts
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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,...
297
297
Jul 11, 2010
07/10
by
Reid, I. A
texts
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The author has identified the following significant results. The fact that water resources data can be retransmitted from remote areas of Canada by polar orbiting spacecraft to users in population centers on a near real time basis reliably, accurately, and at relative low cost continues to be demonstrated. Over 60,000 transmissions from the nine data collection platforms installed at Water Survey of Canada gauging stations have been received. The stage and ice-out data retransmitted via ERTS-1...
Topics: FREQUENCY STANDARDS, LORAN C, SYNCHRONISM, UNIVERSAL TIME, GROUND STATIONS, RADIO NAVIGATION, RADIO...
292
292
Jul 11, 2010
07/10
by
Swanson, E. R.; Kugel, C. P
texts
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Sudden phase anomalies (SPA's) observed on VLF recordings are related to sudden ionospheric disturbances due to solar flares. Results are presented for SPA statistics on 500 events observed in New York during the ten year period 1961 to 1970. Signals were at 10.2kHz and 13.6kHz emitted from the OMEGA transmitters in Hawaii and Trinidad. A relationship between SPA frequency and sun spot number was observed. For sun spot number near 85, about one SPA per day will be observed somewhere in the...
Topics: LONGITUDE, OBSERVATORIES, TIME MEASUREMENT, UNIVERSAL TIME, ASTRONOMY, CLOCKS, INTERNATIONAL...
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256
Jul 11, 2010
07/10
by
Yentsch, C. S.; Owen, W. P
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This study measures the concentrations of phytoplankton chlorophyll and yellow substance in the coastal waters of the Gulf of Maine. Sea surface observations attempt to delineate the principal biochemical parameters responsible for sea surface color. It is shown that the reddish-brown water changed to a blue-green in the open gulf.
Topics: FREQUENCY STABILITY, SYNCHRONISM, TIME, LORAN C, NOISE SPECTRA, SIGNAL TRANSMISSION, DATA...
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209
Jul 12, 2010
07/10
by
Hanel, R. A
texts
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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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200
Jul 23, 2010
07/10
by
Cohen, Herbert A
texts
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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...
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...
136
136
Jul 11, 2010
07/10
by
Davis, D. D
texts
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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,...
Modern digital electronic technology is used to produce a device to convert LORAN C to useful pilot information using a simple software algebra and low cost microprocessor devices. Results indicate that the processor based LORAN C navigator has an accuracy of 1.0 nm or less over an area typically covered by a triad of Loran C stations and can execute a position update in less than 0.2 seconds. The system was tested in 30 hours of flight and proved that it can give reliable and accurate...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, GENERAL AVIATION AIRCRAFT, LORAN C,...
A mathematical model of magnetic variation in the continental United States (COT48) was implemented in the Ohio University LORAN C receiver. The model is based on a least squares fit of a polynomial function. The implementation on the microprocessor based LORAN C receiver is possible with the help of a math chip, Am9511 which performs 32 bit floating point mathematical operations. A Peripheral Interface Adapter (M6520) is used to communicate between the 6502 based micro-computer and the 9511...
Topics: NASA Technical Reports Server (NTRS), COMPUTERIZED SIMULATION, LORAN C, MAGNETIC FIELDS,...
Some of the simpler mathematical equations which may be used in Loran-C navigation calculations were examined. A technique is presented to allow Loran-C time differences to be predicted at a location. This is useful for receiver performance work, and a tool for more complex calculations, such as position fixing.
Topics: NASA Technical Reports Server (NTRS), HYPERBOLIC NAVIGATION, LORAN C, PERFORMANCE PREDICTION, TIME...
The Federal Aviation Administration (FAA) has accepted the Loran-C navigation system as a supplemental navigation aid for enroute use. Extension of Loran-C utilization to instrument approaches requires establishment of a process by which the current level of performance of the system is always known by the pilot. This system 'integrity' translates into confidence that, if the system is made available to the pilot, the guidance will be correct. Early in the consideration of Loran-C for...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, INSTRUMENT APPROACH, LORAN C, NAVIGATION...
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...
A brief description of the Loran-C system is presented with a suggested receiver based on a standard AM-FM integrated circuit chip. Construction details of the Mini-L Loran-C prototype front-end are considered. The Mini-L system was bench tested for approximately 500 hours under a variety of reception conditions. The Mini-L concept combined with a microprocessor system is a promising approach to the development of truly low-cost Loran-C receivers for the marine and airborne user.
Topics: NASA Technical Reports Server (NTRS), ELECTRONIC EQUIPMENT TESTS, LORAN C, MINIATURE ELECTRONIC...
Prototype equipment was developed for flight evaluation which provides enroute navigation in both latitude-longitude and rho-theta coordinates. The nonprecision approach capabilities of this equipment was evaluated. The antenna/preamplifier coupler, the RF processor, tracking loop hardware, tracking loop software, and the video output are discussed. Laboratory and flight test results are evaluated.
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT EQUIPMENT, GENERAL AVIATION AIRCRAFT, LORAN C,...
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,...
A set of programs designed to be run on an IBM 370/158 computer to read the recorded time differences from the tape produced by the LORAN data collection system, convert them to latitude/longitude and produce various plotting input files are described. The programs were written so they may be tailored easily to meet the demands of a particular data reduction job. The tape reader program is written in 370 assembler language and the remaining programs are written in standard IBM FORTRAN-IV...
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, DATA REDUCTION, FLIGHT TESTS, LORAN C,...
LORAN-C a highly accurate radio navigation positioning system which operates at an assigned frequency of 10 kHz, and provides phase-coded pulses to develop hyperbolic time-difference lines-of-position (LOP's) was evaluated. LORAN-C provides precise time and time interval to within plus or minus 5 microseconds of UTC. The steps taken to plan, install, operate, and maintain the LORAN-C system up to the year 2000 are discussed. Topics included in the discussion were: theory of operation, timing,...
Topics: NASA Technical Reports Server (NTRS), COMPONENT RELIABILITY, LORAN C, SYSTEM EFFECTIVENESS, TIME...
The limitations of different E-field antenna coupler or preamplifier circuits are presented. All circuits were evaluated using actual Loran or Omega signals. Electric field whip or wire antennas are the simplest types which can be used for reception of VLF signals in the 10 to 100 kHz range. JFET or MOSFET transistors provide impedance transformation and some voltage gain in simple circuits where the power for operating the preamplifier uses the same coaxial cable that feeds the signal back to...
Topics: NASA Technical Reports Server (NTRS), ANTENNA COUPLERS, COUPLING CIRCUITS, LORAN C, PREAMPLIFIERS,...
A set of programs used to plot Loran C lines of position on any common map or standard aviation sectional chart are given. The Loran C plotting program JRPLOT FORTRAN uses a standard Calcomp compatible plotting subroutine package for the Hewlett-Packard 7203A graphic plotter. The programs are designed to be run on an IBM System 370 computer. A simple add subtract method is used to calculate the lines of position. A description of how to use the program and some methods of operation are given.
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, LORAN C, NAVIGATION AIDS, PLOTTING,...
The ship position and attitude measurement system that was installed aboard the tracking ship Vanguard is described. An overview of the entire system is given along with a description of how precise time and frequency is utilized. The instrumentation is broken down into its basic components. Particular emphasis is given to the inertial navigation system. Each navigation system used, a mariner star tracker, navigation satellite system, Loran C and OMEGA in conjunction with the inertial system is...
Topics: NASA Technical Reports Server (NTRS), LORAN C, SATELLITE NAVIGATION SYSTEMS, SHIPS, TRACKING...
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,...
The methods used in forming time scales for distant sites monitoring LORAN-C are addressed. The time transfers obtained via the defense satellite communication system (DSCS) and the data provided by this system used to calibrate these remote time scales are emphasized. The errors involved are discussed.
Topics: NASA Technical Reports Server (NTRS), CALIBRATING, DEFENSE COMMUNICATIONS SATELLITE SYSTEM, LORAN...
Full hardware documentation is provided for the circuit card implementing the Loran-C timing loop, and the receiver event-mark and re-track functions. This documentation is to be combined with overall receiver drawings to form the as-built record for this device. Computer software to support this module is integrated with the remainder of the receiver software, in the LORPROM program.
Topics: NASA Technical Reports Server (NTRS), LOOPS, LORAN C, TIMING DEVICES, COMPUTER PROGRAMS,...
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 LORAN program is stored in CMS disk files for use by Avionics Engineering Center terminal users. A CMS EXEC file named LORAN controls program operation. The user types LORAN and the program then prompts for data input and produces output on the terminal. The FORTRAN program refers to a disk file of LORAN master data giving station locations, coding delays, repetition rate and station pair identification letters. For Geographic-to-LORAN conversion, no iterative computations are required; the...
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, LORAN C, NAVIGATION AIDS, AIR NAVIGATION,...
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.
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,...
Portable battery operated LORAN-C receivers were fabricated to evaluate simple envelope detector methods with hybrid analog to digital phase locked loop sensor processors. The receivers are used to evaluate LORAN-C in general aviation applications. Complete circuit details are given for the experimental sensor and readout system.
Topics: NASA Technical Reports Server (NTRS), GENERAL AVIATION AIRCRAFT, LORAN C, PHASE LOCKED SYSTEMS,...
A closed circuit flight test was conducted in the Boston area using VOR's and NDB's as reference points. The Loran-C data collected during the flight was then compared against a reference provided by the Discrete Address Beacon System (DABS) facility at Lincoln Laboratories. A MIT crew used a commercial receiver and recorded Loran-C time differences which would also be compared with the data provided by the DABS facility and eventually with the data collected by Ohio University. The Ohio...
Topics: NASA Technical Reports Server (NTRS), COORDINATES, FLIGHT TESTS, LORAN C, NAVIGATION AIDS,...
The environment in which a LORAN-C Timing Receiver may function effectively depends to a large extent on the techniques utilized to insure that interfering signals within the pass band of the unit are neutralized. The baseline performance manually operated timing receivers is discussed and the basic design considerations and necessary parameters for an automatic unit utilizing today's technology are established. Actual performance data is presented comparing the results obtained from a present...
Topics: NASA Technical Reports Server (NTRS), DATA ACQUISITION, LORAN C, SIGNAL TO NOISE RATIOS, TIME...
The long term performance of the eight LORAN-C chains is presented in terms of the Coordinated Universal Time (UTC) of the U.S. Naval Observatory (USNO); and the use of the LORAN-C navigation system for maintaining the user's clock to a UTC scale is described. The atomic time scale and the UTC of several national laboratories and observatories relative to the international atomic time are reported. Typical performance of several NASA tracking station clocks, relative to the USNO master clock,...
Topics: NASA Technical Reports Server (NTRS), LORAN C, TIME MEASUREMENT, TIME SIGNALS, CLOCKS,...
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 research conducted during 1988 to 1989 under the NASA/FAA-sponsored Joint University Program for Air Transportation Research is summarized. The Joint University Program is a coordinated set of three grants sponsored by NASA Langley Research Center and the Federal Aviation Administration, one each with the Massachusetts Institute of Technology, Ohio University, and Princeton University. Completed works, status reports, and annotated bibliographies are presented for research topics, which...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AIR TRAFFIC CONTROL, AIR TRANSPORTATION,...
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,...
Control of time and frequency at remote stations and the maintenance of a constant time scale for LORAN-C chains are problems of practical importance. The stability of stations monitoring a LORAN-C chain is analyzed, in particular, those stations monitoring the Northwest Pacific chain. Individual determinations of the quantity, U.S. Naval Observatory Master lock are compared with an averaged value and monitored data.
Topics: NASA Technical Reports Server (NTRS), ELECTRONIC CONTROL, LORAN C, NAVIGATION INSTRUMENTS, TIME...
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...
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...
The common time measurements as used by the U.S. Air Force Measurements and Standards Laboratory, Aerospace Guidance and Metrology Center (AGMC), Newark Air Force Station, Ohio, are described. Electronic counter time interval measurements are emphasized since this is the most common time comparison measurement in use. The proper use and setting of controls will be covered along with helpful hints and common mistakes to be avoided. Applications of time measurements are described and some of...
Topics: NASA Technical Reports Server (NTRS), COUNTERS, MILITARY TECHNOLOGY, TIME MEASUREMENT, FREQUENCY...
A time and frequency intercomparison experiment conducted using Earth stations in New Delhi, India and Raisting, FRG is described. The NPL clock was placed at New Delhi Earth Station and the Raisting Clock was calibrated with PTB/Primary standard via LORAN-C and travelling clocks. The random uncertainity of time comparisons, represented by two sample Allan Variance sigma (30 seconds), was less than 10 nanoseconds. The relative frequency difference between the NPL and Raisting Clocks, SNPL,...
Topics: NASA Technical Reports Server (NTRS), FREQUENCY STANDARDS, INDIA, SYMPHONIE SATELLITES, TIME...
Radio navigation systems which offer the capabilities of area navigation to general aviation operators are discussed. The systems considered are: (1) the VORTAC system, (2) the Loran-C system, and (3) the Differential Omega system. The inital analyses are directed toward a comparison of the systems with respect to their compliance to specified performance parameters and to the cost effectiveness of each system in relation to those specifications. Further analyses lead to the development of...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AREA NAVIGATION, GENERAL AVIATION AIRCRAFT,...
An inexpensive data/command entry and CRT display system capable of alphanumeric and graphics moe operation and designed to operate in place of a separate ASCII terminal, is documented. The software to interface this unit to the 6502-based Loran C receiver is also described. The system simplifies receiver operations to a level typical of current avionics systems.
Topics: NASA Technical Reports Server (NTRS), ALPHANUMERIC CHARACTERS, CATHODE RAY TUBES, COMPUTER...
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,...
Two Loran C monitors, at Galion and Athens, Ohio, were operated over a one-year period, measuring chain 9960 Time Delay (TD) and Signal to Noise Ratio (SNR). Analysis of data concentrated on correlation of short term TD variations during the winter months of 1985 to 86, over the 92 nm baseline. Excellent correlation was found, with slight additional improvement possible if local temperature is also included in the analysis. Although SNR and TD effects were suspected during the presence of...
Topics: NASA Technical Reports Server (NTRS), DATA CORRELATION, INSTRUMENT APPROACH, LORAN C, SIGNAL TO...
