ENHANCED POINTING GIMBAL MECHANISMS FOR NEXT GENERATION COMMUNICATION ANTENNAS

摘要

This paper summarizes the design and the developmentrnof a family of high precision Enhanced Pointing GimbalrnAssemblies (EPGA) specifically targeting the nextrngeneration of satellite communication antennarntechnologies.rnThe development and qualification of the first twornEPGAs started some years ago. The purpose of thisrnproject has been to develop a gimbal based on a newrnrotary actuator technology achieving positioningrnperformance superior to micro-stepping performance, tornbe used in highly accurate pointing and scanningrnmechanisms. The design also had to provide highrnstiffness and high load carrying capacity at the outputrnstage.rnThe design of this new line of gimbals is based on arnrotary actuator with a high gear reduction ratio and highrnload carrying capacity output stage.rnAnalysis of the latest missions, especially those forrncommunication, earth observation and imaging, showrnthat performance requirements for dual axis gimbalsrnused for antenna pointing are becoming more and morerndemanding. Most recent Ka-band and future generationrnantenna technologies for smaller spot beams requirernfiner resolutions of less than 0.003 degrees.rnConsiderably larger solid core (～ 3.0 meter diameter)rnand expandable wire-mesh (～22 meter diameter)rnrequire higher load carrying capabilities and momentrnstiffness to sustain the launch and orbital maneuveringrnloads. The developed Enhanced Pointing GimbalrnAssembly addresses those applications requiring smallrnoutput step size, high precision pointing, and unpoweredrnholding torque, which challenge the use ofrngimbals that use conventional rotary actuators.