Accession Number : AD0775144

Title :   Design of an Autonomous Stationkeeping Controller for LES-8/9.

Descriptive Note : Technical note,

Corporate Author : MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB

Personal Author(s) : Srivastava,Sushanta ; Brockett,Roger W.

Report Date : 21 FEB 1974

Pagination or Media Count : 62

Abstract : The report describes the design of the controller and digital filter for the LES-8/9 autonomous stationkeeping system. The design goals are to maintain a station with plus or minus 0.15 deg. accuracy with an efficient thruster fuel usage and execute automatic station changes when necessary at a controlled coasting speed. These goals are accomplished by using a time-varying eighth-and sixteenth-order filter, and a non-linear controller with switching zones. The final design is optimized taking into account stochastic nature of the navigation error. The controller parameters and filters can be altered in orbit to achieve the optimum performance for the navigation error seen in orbit. (Author)

Descriptors :   *SYNCHRONOUS SATELLITES, *TRANSFER TRAJECTORIES, *ATTITUDE CONTROL SYSTEMS, THRUSTERS, MANEUVERING SATELLITES, DIGITAL FILTERS, PERTURBATIONS, FUEL CONSUMPTION

Subject Categories : Unmanned Spacecraft
      Spacecraft Trajectories and Reentry

Distribution Statement : APPROVED FOR PUBLIC RELEASE