Simplified antenna controller system operation manual
A simplified controller system for a seven element phase array antenna is described, and information necessary for operation of the system is given.
Doland, G. D.↗
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Large Deployable Antenna Shuttle Experiment
An experiment designed to use the Space Shuttle in tests of the mechanical and electrical properties of spaceborne deployable antennas under zero-gravity conditions is outlined. Space-erectable 20-meter diameter phased arrays or reflector/feed systems, and self-deploying mechanisms, are to be tested. Reflector surface integrity will be tested by an AM laser technique, and electrical behavior will be tested by a spin-stabilized RF beacon injected into orbit prior to unfurlment of the antenna. Focusing and gain measurements, static pattern measurements, dynamic RF gain measurements, and measurements of cross-polarized signals will be conducted, and the reflector will be illuminated by separate feeds for the S-, X-, and K-bands. Mechanical features of the mesh-wrapped rib furlable antenna design are described.
Freeland, R. E.↗
Space Shuttle communications experiments
Experiments which are under consideration for possible flight on the Space Shuttle in the 1980's to aid in the development of new communications techniques are outlined. A millimeter wave communications experiment for the study of propagation above 10 GHz and an electromagnetic environment experiment for the characterization of fields in orbit are planned to provide information needed for effective spectrum conservation. An antenna range experiment is being studied to provide an in-orbit far-field RF signal source for measuring ground antenna patterns and gain over a wide frequency range. Additional experiments will be intended to test spacecraft technology developments, including such communications system components as large phased array antennas and solid state transmitters and receivers.
Wolff, E. A.↗
Advanced propulsion concepts study: Comparative study of solar electric propulsion and laser electric propulsion
Solar electric propulsion (SEP) and laser electric propulsion (LEP) was compared. The LEP system configuration consists of an 80 kW visible laser source on earth, transmitting via an 8 m diameter adaptively controlled phased array through the atmosphere to a 4 m diameter synchronous relay mirror that tracks the LEP spacecraft. The only significant change in the SEP spacecraft for an LEP mission is the replacement of the two 3.7 m by 33.5 m solar cell arrays with a single 8 m diameter laser photovoltaic array. The solar cell array weight is decreased from 320 kg to 120 kg for an increase in payload of 200 kg and a decrease in specific mass of the power system from 20.5 kg/kW to 7.8 kg/kW.
Forward, R. L.↗
Feasibility and systems definition study for microwave multi-application payload (MMAP)
There were three Shuttle/Spacelab experiments: adaptive multibeam phased array antenna (AMPA) experiment, electromagnetic environment experiment (EEE), and millimeter wave communications experiment (MWCE). Work on the AMPA experiment was completed. Results included are definition of operating modes, sequence of operation, radii of operation about several ground stations, signal format, foot prints of typical orbits and preliminary definition of ground and user terminals. Definition of the MOD I EEE included conceptual hardware designs, spacelab interfaces, preliminary data handling methods, experiment tests and verification, and EMC studies. The MWCE was defined conceptually for a steerable high gain antenna.
Horton, J. B.↗
OSU participation in the CTS communications link characterization experiment
A four element self phased array was developed for propagation measurements utilizing the Communication Technology Satellite 11.7 GHz downlink. The parameters of interest in measurements were attenuation, amplitude scintillation, and angle of arrival variability. Simultaneous scintillation measurements were also conducted at 360 MHz, 2.075 GHz, and 30 GHz utilizing ATS-6. The unique movement of ATS-6 during 1976 permitted extensive measurement of scintillation characteristics as a function of path elevation angle.
Hodge, D. B.↗
Feasibility and systems definition study for Microwave Multi-Application Payload (MMAP)
Work completed on three Shuttle/Spacelab experiments is examined: the Adaptive Multibeam Phased Array Antenna (AMPA) Experiment, Electromagnetic Environment Experiment (EEE) and Millimeter Wave Communications Experiment (MWCE). Results included the definition of operating modes, sequence of operation, radii of operation about several ground stations, signal format, foot prints of typical orbits and preliminary definition of ground and user terminals. Conceptual hardware designs, Spacelab interfaces, data handling methods, experiment testing and verification studies were included. The MWCE-MOD I was defined conceptually for a steerable high gain antenna.
Horton, J. B.↗
Static inverter with synchronous output waveform synthesized by time-optimal-response feedback
Time-optimal-response 'bang-bang' or 'bang-hang' technique, using four feedback control loops, synthesizes static-inverter sinusoidal output waveform by self-oscillatory but yet synchronous pulse-frequency-modulation (SPFM). A single modular power stage per phase of ac output entails the minimum of circuit complexity while providing by feedback synthesis individual phase voltage regulation, phase position control and inherent compensation simultaneously for line and load disturbances. Clipped sinewave performance is described under off-limit load or input voltage conditions. Also, approaches to high power levels, 3-phase arraying and parallel modular connection are given.
Kernick, A.↗
Advanced microwave radiometer antenna system study
The practicability of a multi-frequency antenna for spaceborne microwave radiometers was considered in detail. The program consisted of a comparative study of various antenna systems, both mechanically and electronically scanned, in relation to specified design goals and desired system performance. The study involved several distinct tasks: definition of candidate antennas that are lightweight and that, at the specified frequencies of 5, 10, 18, 22, and 36 GHz, can provide conical scanning, dual linear polarization, and simultaneous multiple frequency operation; examination of various feed systems and phase-shifting techniques; detailed analysis of several key performance parameters such as beam efficiency, sidelobe level, and antenna beam footprint size; and conception of an antenna/feed system that could meet the design goals. Candidate antennas examined include phased arrays, lenses, and optical reflector systems. Mechanical, electrical, and performance characteristics of the various systems were tabulated for ease of comparison.
Kummer, W. H.↗
A communications satellite system concept based on the AMPA experiment
This paper describes a system employing sophisticated satellites with steerable high gain, multibeam phased array antennas, which serve small low-cost user terminals. Adaptive techniques are used to form, point, and shape the beams. Pseudonoise signaling achieves user access/distress without requiring dedicated access/emergency channels. The L-band array has 32 elements, 34-dB gain; the user terminal has 15W transmitter, 3-dB gain antenna. The pseudonoise code and message structures are described. Approximately 100 users can be simultaneously acquired with success-probability exceeding 99%; system capacity can be increased by providing additional beams. System implementation is feasible in the Shuttle era.
Durrani, S. H.↗
A review of performance characteristics of satellite antennas and some observations on future directions in satellite antenna design
A general review of the state-of-the-art and new directions in research and development of spacecraft antennas is presented. Three general classes of antennas are discussed: phased arrays, lenses (dielectric and waveguide), and reflector antennas. Presently, the antenna with most applications is the reflector with considerable research being performed to improve its scan and multiple beam characteristics. Future applications for spacecraft antennas and research goals to meet these projected needs also are discussed.
Mittra, R.↗
Candidate solar cell materials for photovoltaic conversion in a solar power satellite /SPS/
In recognition of the obstacles to solar-generated baseload power on earth, proposals have been made to locate solar power satellites in geosynchronous earth orbit (GEO), where solar energy would be available 24 hours a day during most of the time of the year. In an SPS, the electricity produced by solar energy conversion will be fed to microwave generators forming part of a planar phase-array transmitting antenna. The antenna is designed to precisely direct a microwave beam of very low intensity to one or more receiving antennas at desired locations on earth. At the receiving antenna, the microwave energy will be safely and efficiently reconverted to electricity and then be transmitted to consumers. An SPS system will include a number of satellites in GEO. Attention is given to the photovoltaic option for solar energy conversion in GEO, solar cell requirements, the availability of materials, the implication of large production volumes, requirements for high-volume manufacture of solar cell arrays, and the effects of concentration ratio on solar cell array area.
Glaser, P. E.↗
Limited scan dual-band high-gain antenna
Dual band communication and tracking antenna concept combines S- and X-band high gain performance in near field cassagrainian configuration. Design incorporating subreflector in near field of feed permits limited electronic scanning with phased array feed of approximately subreflector size placed in region between subreflector and main reflector.
Cramer, P. W., Jr.↗
Wide-beam flush-mounted antenna
Compact six-element S-band phased-array antenna produces exceptionally broad, circularly polarized beam and wide bandwidth. Suitable for flush mounting, antenna may be useful in high altitude aircraft, communication satellites, and ground-based moving vehicles.
Ellis, H., Jr.↗
Design considerations for solar power satellites
This report summarizes the performance characteristics of a conceptual solar power satellite (SPS) system with emphasis on the microwave power transmission system. The latest tradeoff studies on photovoltaic and thermal systems for converting solar energy into electricity at the satellite are reviewed. The microwave system, consisting of dc-RF amplifiers, a 1-km phased array, and a ground antenna/rectifier scheme is capable of delivering 5 GW of power to the commercial grid. The transmission efficiencies of smaller system sizes (down to 1 GW) are compared with that of the nominal 5 GW system. At present the frequency region of interest is the IMS (industrial, medical, and scientific) band at 2450 plus or minus 50 MHz. Economic and technical tradeoffs as a function of the microwave operating frequency are considered. Candidate dc-RF power converter tubes, including medium-power amplitrons, high-power klystrons, and low-power solid state amplifiers, are examined.
Arndt, G. D.↗
Technology requirements for an orbital navigation/position finding system
The concept of an orbiting personal navigation system as a possible application for a large space structure is considered. The navigation system would have to be part of a large, integrated, multifunction Information Service Platform to justify its complexity and assured use by a large segment of the civilian population. The navigation configuration is a large cruciform which utilizes a linear phased array antenna design. The two antenna arms generate narrow, orthogonal beam patterns on the ground which are electrically scanned east to west and south to north. A passive ground receiver detecting the beam passage determines the user's position in earth longitude and latitude coordinates.
Lang, A. L., Jr.↗
SPS phase control system performance via analytical simulation
A solar power satellite transmission system which incorporates automatic beam forming, steering, and phase control is discussed. The phase control concept centers around the notation of an active retrodirective phased array as a means of pointing the beam to the appropriate spot on Earth. The transmitting antenna (spacetenna) directs the high power beam so that it focuses on the ground-based receiving antenna (rectenna). A combination of analysis and computerized simulation was conducted to determine the far field performance of the reference distribution system, and the beam forming and microwave power generating systems.
Lindsey, W. C.↗
SPS antenna pointing control
The pointing control of a microwave antenna of the Satellite Power System was investigated emphasizing: (1) the SPS antenna pointing error sensing method; (2) a rigid body pointing control design; and (3) approaches for modeling the flexible body characteristics of the solar collector. Accuracy requirements for the antenna pointing control consist of a mechanical pointing control accuracy of three arc-minutes and an electronic phased array pointing accuracy of three arc-seconds. Results based on the factors considered in current analysis, show that the three arc-minute overall pointing control accuracy can be achieved in practice.
Hung, J. C.↗