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Small signal characteristics and estimated limits of interchangeable electronics assembly for Apollo tracking antenna system
Tracking antenna system with array for synchronous satellite or ground based radar
The present invention is an auto tracking antenna platform upon which multiple antenna elements can be mounted to track a common moving object. The antenna tracking platform generally comprises a bottom pedestal enclosing a rotary azimuth actuator for controlled-rotary motion about the single vertical (z) axis, and an upper multi-tier framework housing a horizontal antenna-mounting beam pivotally supported for rotation about a horizontal (x) axis, and a drive assembly for direct-drive rotation of the antenna-mounting bar. Antenna elements are mounted along the horizontal mounting bar and the feeds routed through the azimuth actuator. This enables the use of fiber optic rotary joints or slip rings to pass data and video, instead of RF (waveguide) rotary joints which are required to pass high power RF signals.
Cassegrain monopulse tracking antenna for LEM and Command Module rendezvous guidance
The implementation of a satellite tracking and antenna control system is described. Due to the loss of inclination control for the symphonie satellites, it became necessary to equip the parabolic antennas of the mobile Symphonie ground station with tracking facilities. For the relatively low required tracking accuracy of 0.5 dB, a low cost, step track system was selected. The step track system developed for this purpose and tested over a long period of time in 7 ground stations is based on a search step method with subsequent parabola interpolation. As compared with the real search step method, the system has the advantage of a higher pointing angle resolution, and thus a higher tracking accuracy. When the pilot signal has been switched off for a long period of time, as for instance after the eclipse, the antenna is repointed towards the satellite by an automatically initiated spiral search scan. The function and design of the tracking system are detailed, while easy handling and tracking results.
Eddy current clutch drives for tracking antenna system
An antenna system including antenna elements and a satellite tracking method is considered a key technology in implementing land mobile satellite communications. In the early stage of land mobile satellite communications, a mechanical tracking antenna system is considered the best candidate for vehicles, however, a phased array antenna will replace it in the near future, because it has many attractive advantages such as a low and compact profile, high speed tracking, and potential low cost. Communications Research Laboratory is now developing a new phased array antenna system for land vehicles based on research experiences of the airborne phased array antenna, which was developed and evaluated in satellite communication experiments using the ETS-V satellite. The basic characteristics of the phased array antenna for land vehicles are described.
Turnstile conical scan feed to improve tracking antenna performance on Apollo-instrumented ships
This paper describes the application of Artificial Intelligence planning techniques to the problem of antenna track plan generation for a NASA Deep Space Communications Station.
Signal from satellite tracked in moving vehicle. L-band, mechanically-steered, medium-gain antenna part of prototype radio equipment mounted in vehicle to demonstrate concept of land-mobile/satellite communication system. Provides such services as mobile telephone, voice or alphanumeric dispatch, paging, position-location information, and low-rate data transmission, for users within continental United States and Alaska. Antenna rotated mechanically until it finds direction from which maximum signal comes. Rate sensors provide inertial frame of reference during acquisition, so antenna locks onto signal even when vehicle turning.
Multipath interference effects on Apollo S band and lunar module steerable antenna tracking system
Mathematical model for radio frequency circuitry of Apollo high gain antenna system
The design and development of a continuous duty cycle antenna tracking mechanism (ATM) for geostationary communications satellites is described. The FACC requirements for an ATM and description of the development mechanism designed and built for the program are presented. The mechanism mechanical configuration and component performance is documented along with its launch and operational constraints. The proposed development tests and the results of computer simulations are discussed. The advantages of this mechanism are its simplicity with inherent reliability, low mass, high stiffness, and ability to accurately point a wide range of antenna sizes.
Analysis of comparators used in CSM high gain antenna tracking system
Circularly polarized antenna evaluation
An antenna for use on an aircraft has been developed and tested for transmissions to and from a communications satellite. The antenna operates at 20/30 GHz and a data rate of 512 kbps, and it does not require modifying the shape of the aircraft fuselage.
Antenna feed features high aperture efficiency of multimode near-field horn and develops tracking signals without conventional monopulse bridge. Feed assembly is relatively simple and very compact. However, feed is sensitive to cross-polarized energy which couples into orthogonal error channel.
Utilize coaxial horn feed to illuminate reflector; feed has inner horn for X-band, and outer horn for S-band. Tracking error signals for servo correction are derived from measurements of relative phase and relative amplitude between two modes.