Inertially stabilized platforms for SATCOM on-the-move applications : a hybrid open/closed-loop antenna pointing strategy

The increasing need for timely information in any environment has led to the development of mobile SATCOM terminals. SATCOM terminals seeking to achieve high data-rate communications require inertial antenna pointing to within fractions of a degree. The base motion of the antenna platform complicates the pointing problem and must be accounted for in mobile SATCOM applications. Antenna Positioner Systems (APSs) provide Inertially Stabilized Platforms (ISPs) for accurate antenna pointing and may operate in either an open or closed-loop fashion. Closed-loop antenna pointing strategies provide greater inertial pointing accuracies but typically come at the expense of more complex and costly systems. This thesis defines a nominal two-axis APS used on an EHF SATCOM terminal on a 707 aircraft. The nominal APS seeks to accomplish mobile SATCOM using the simplest possible system; therefore, the system incorporates no hardware specific to closed-loop pointing. This thesis demonstrates that the nominal APS may achieve accurate antenna pointing for an airborne SATCOM application using a hybrid open/closed-loop pointing strategy. The nominal APS implements the hybrid pointing strategy by employing an open-loop pedestal feedback controller in conjunction with a step-tracking procedure. The open-loop feedback controller is developed using optimal control techniques, and the pointing performance of the controller with the nominal APS is determined through simulation. This thesis develops closed-loop step-tracking algorithms to compensate for open-loop pointing errors.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Marsh, Eric Allen

Advisor dc:contributor.advisor

• Dan Asta, Timothy Gallagher and Jonathan P. How.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/45259

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/45259