Wide angular coverage circularly polarized antenna for NavSat application.
Airborne wide angular coverage circularly polarized antenna designs with hemispherical patterns for navigation satellite system application
Wong, G. G.↗
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Navigation and control.
Aircraft navigation aids and flight control equipment, discussing inertial navigators with digital computers and navigation satellites
Hayes, R. J.↗
Consecutive tracking of landmarks - By an active satellite and then by a Martian roving vehicle
Satellite navigation method for locating Mars landmark or target point for exploration by roving vehicle located as center of coordinate system
Janosko, R. E.↗
Integrated operations payloads/fleet analysis study extension report
An analysis of the factors affecting the cost effectiveness of space shuttle operations is presented. The subjects discussed are: (1)payload data bank, (2) program risk analysis, (3)navigation satellite program, and (4) reusable launch systems.
Source record↗
Unmanned spacecraft for research
The applications of unmanned spacecraft for research purposes are discussed. Specific applications of the Communication and Navigation satellites and the Earth Observations satellites are described. Diagrams of communications on world-wide basis using synchronous satellites are developed. Photographs of earth resources and geology obtained from space vehicles are included.
Graves, C. D.↗
New space technology advances knowledge of the remote polar regions
The application of ERTS-1 imagery is rapidly increasing man's knowledge of polar regions. Products compiled from this imagery at scales of 1:250,000, 1:500,000 and 1:1,000,000 are already providing valuable information to earth scientists working in Antarctica. Significant finds detected by these bench mark products were glaciological changes, advancement in ice fronts, discovery of new geographic features, and the repositioning of nunataks, islands, and ice tongues. Tests conducted in Antarctica have proven the feasibility of tracking Navy navigation satellites to establish ground control for positioning ERTS-1 imagery in remote areas. ERTS imagery coupled with satellite geodesy shows great promise and may prove to be the most practical and cost effective way to meet the small-scale cartographic requirements of the polar science community.
Macdonald, W. R.↗
Use of the Space Shuttle for communications and navigation experiments
It is seen that a Shuttle laboratory will provide a facility for meeting the continuing need for planning frequency and orbit utilization and specialized radio interference measurements. The Shuttle could be used for placing communications and navigation satellites into the desired orbit, and also for conducting laser communications tests with the aim of developing the required technology and acquisition techniques for space-to-space and space-to-ground telecommunications. Other uses include the proof-testing of large spacecraft antenna structures and their erection mechanisms, and the testing of high-voltage high-current communications satellite components and subsystems.
Marsten, R. B.↗
British American satellite time transfer experiment
The use of the Timation satellite for navigation purposes is discussed. The advantages of the satellite for navigation and time transfer are defined as: (1) well-known position, (2) line-of-sight signal which allows use of ultrahigh frequency signals, (3) worldwide coverage, and (4) celestial navigation solution similar to the conventional celestial navigation practices. A diagram of range measurement by phase measure is provided. The application of an intercept chart for determining position using the navigation satellite is demonstrated. The results of a ground based time transfer experiment are reported.
EASTON R. L.↗
Measurements of transient currents in mid-ocean by altimetry
Evidence is put forward that SEASAT-A altimetry will be accurate enough to provide interesting information on transient currents in mid-ocean areas. The discussion rests on the assumption that the observed currents are largely in geostrophic equilibrium rather than due to local winds. Surface current velocities are determined by integrating satellite navigation positions and dead reckoning data using an automatic log attached to a vessel hull.
Bryan, K.↗
NASA tracking ship navigation systems
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 described. The accuracy of each system is compared along with their limitations.
Mckenna, J. J.↗
TRAN*STAR 2 evaluation for NOAA data buoy office, part A
The capability of the TRAN*STAR 2 receiver equipment utilizing the U.S. Navy Navigation Satellite System to provide reliable position locations with reasonable accuracy and frequency was evaluated. Two receivers, an antenna, and a test set were procured, and position fix data collected at NSTL from a fixed known location during the months of May and June. The data were processed through a computer program and analyzed. The results of the evaluation are summarized.
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Application of optimum smoothing for image distortion correction
Optimum linear smoothing is utilized to estimate certain distortions in LANDSAT-D images. Measurements that are processed by the smoother consist of designated control of point locations within the images. Image distortions that are estimated by the smoother are those induced by LANDSAT-D satellite navigation errors and slowly varying attitude and sensor alignment uncertainties. Preliminary results indicate that optimum smoothing produces substantially more accurate distortion estimates than optimum filtering and that optimum smoothing may reduce the number of control points needed to yield desired image correction accuracy.
Werner, R. A.↗
Evolution of the International Atomic Time TAI computation
The computation of the International Atomic Time (TAI), a worldwide time reference, is briefly examined. The types of atomic clocks, computation procedures, and time intercomparison between clocks utilizing navigation satellites are addressed. Changes in the system would essentially depend on the improvement of the atomic clocks.
Granveaud, M.↗
Astrodynamics 1979; Proceedings of the Conference, Provincetown, Mass., June 25-27, 1979. Parts 1 & 2
Topics are presented on navigation systems, inner planets, comets and asteroids, outer planets, earth orbital applications, and computational methods. Individual subjects include an overview of the Navstar Global Positioning System and the Navy Navigation Satellite System, the solar probe mission, Uranus mission options, as well as a study of lifetimes of geosynchronous transfer orbits, and the price of oil in the year 2000.
Penzo, P.↗
Fifth Annual Flight Mechanics/Estimation Theory Symposium
Various aspects of astrodynamics are considered including orbit calculations and trajectory determination. Other topics dealing with remote sensing systems, satellite navigation, and attitude control are included.
Teles, J.↗
Semiannalytical satellite theory and sequential estimation
Kalman filtering techniques are combined with a semianalytical orbit generator to develop a sequential orbit determination algorithm. The algorithm is investigated for computational efficiency, accuracy, and radius of convergence by comparison with truth ephemerides and a Cowell special perturbations filters (GTDS). Test cases relevant to satellite navigation are examined.
Taylor, S. P.↗
Effects of ionospheric turbulence on SPS pilot signal
The spatial variation of the electron density was studied by monitoring the differential Doppler on radio beacons aboard the Navy navigation satellites. The radio frequency heater was used to deposit energy in the F-region ionosphere with the heating frequency above peak plasma frequency. The effects of the solar power satellite power beam on the pilot signal were simulated. It was found that a small depletion was formed in the beam and that there was turbulence in the elctron density up the magnetic field line from the beam. It is suggested that the depletion will not seriously affect the power or pilot beams of the solar power satellite.
Clynch, J. R.↗
Vacuum pumping system for spaceborne passive hydrogen masers
The ultimate utility of hydrogen masers as highly accurate clocks aboard navigation satellites depends on the feasibility of making the maser lightweight, compact, and capable of a 5 to 7 year unattended operation. A vacuum pumping system for the maser that is believed to meet these criteria was designed and fabricated. The pumping system was fabricated almost completely from 6Al-4V titanium alloy and incorporates two or four sintered zirconium carbon getter pumps with integral activation heaters. The manner in which the getter pumps were mounted to insure that they will stand both the activation and the shock of launch is illustrated. Data on the total hydrogen capacity and pumping of this system is also presented.
Wolf, S. A.↗