Accession Number : ADA337591

Title :   Design and Evaluation of a Directional Antenna for Ocean Buoys.

Descriptive Note : Technical rept.,

Corporate Author : WOODS HOLE OCEANOGRAPHIC INSTITUTION MA

Personal Author(s) : Frye, Daniel ; Doherty, Ken ; Hinton, Al

PDF Url : ADA337591

Report Date : NOV 1997

Pagination or Media Count : 68

Abstract : A system concept has been developed by Viasat, Inc. and Woods Hole Oceanographic Institution for improving the data telemetry bandwidth available on ocean buoys. This concept utilizes existing communications satellites as data relay stations and mechanically steered antenna arrays to achieve increased data rates and improved power efficiency needed for ocean applications. This report describes an initial feasibility and design study to determine if a mechanically steered antenna array can meet the requirements of open ocean buoy applications. To meet the system requirements, an 18-element microstrip antenna (9-element transmit, 9-element receive) was designed and fabricated under subcontract by Seavey Engineering Associates, Inc. It operates in the 4-6 GHz frequency band (C-band) and provides 14 dB of gain. The % power beamwidth is j150 in azimuth and elevation. This antenna design, in conjunction with a simple rotating mount, was used to evaluate the potential of this approach to keep a geostationary satellite in view when mounted on an ocean buoy. The evaluation is based on laboratory measurements using a magnetic compass and a small stepper motor to maintain antenna orientation while the complete assembly was rotated and tilted at speeds similar to what would be expected on an offshore buoy equipped with a stabilizing wind vane.

Descriptors :   *BANDWIDTH, *BUOYS, *TELEMETER SYSTEMS, *DIRECTIONAL ANTENNAS, VELOCITY, MEASUREMENT, STEERING, DATA TRANSMISSION SYSTEMS, ORIENTATION(DIRECTION), EFFICIENCY, STEPPER MOTORS, MOUNTS, POWER, DATA RATE, COMPASSES, MAGNETIC DEVICES, ELEVATION, DATA LINKS, ROTATION, ANTENNA ARRAYS, COMMUNICATION SATELLITES, TILT, OPEN WATER, OFFSHORE, SYNCHRONOUS SATELLITES, RADIO RELAY STATIONS, OCEANOGRAPHIC EQUIPMENT.

Subject Categories : Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE