Brian J. d'Auriol, Ph.D.

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Tanushree Ghosh, Computation, Communication, Command and Control (C4) in a Satellite Cluster, Department of Computer Science, The University of Texas at El Paso, May 2004. Advisor: Brian J. d'Auriol

Abstract
Computation, Communication, Command and Control (C4) is an integral part of a satellite cluster communication system. Computation is defined as the process of finding a solution to a problem from given inputs by means of an algorithm. Communication is defined as the exchange or transfer of data between processes or systems using some existing rules or protocols. Command and control (C2) is defined by JPL as ``... the exercise of authority and direction by a properly designated commander ... in the accomplishment of [a] mission. Command and Control functions are performed through an arrangement of personnel, equipment, communications, facilities and procedures employed by a commander in planning, directing, coordinating and controlling forces and operations ...''. This definition of C2 is complimented by the definition of command and control by the Air Force Policy Directive 10-2. It is suggested in these definition of C2 that computation and communication are inseparable from command and control. It is reasonable to consider the interaction of all four parts, that is, C4.

A prevalent view of a satellite system is that of cluster satellites. A cluster satellite is a group of satellites that communicate with each other in order complete a task. Command and control requirements for cluster satellites have been well identified in programs by the AFRL and NASA. This research considers the scenario of a deep space remote sensing of asteroids by a satellite cluster. In this scenario, a cluster of satellites is deployed and take positions around the asteroid and probes it for information. Types of anticipated sensing includes imaging, radar, x-ray, infra-red imagery and physical collection of data. The satellite cluster would process information from these sensors, e.g., image processing, in a distributed computing environment. The satellites in the cluster need to communicate in order to support the computational requirements for these kinds of applications.

In this thesis, a C4 Model is developed to capture the computation, communication, command and control requirements of the satellite cluster system deployed based on the scenario. An initial graph abstraction of the satellite cluster is helpful in modeling the system requirements of the scenario as well as the interaction of the four components (C4) of the cluster communication system. The different types of communication that occur due to the computations and command and control (C2) requirements are explored. As a part of the research work, a simulation of the scenario is done. Simulation results show how the system components are updated and managed in a highly dynamic network system. This thesis also discusses the type of protocol that is best suited for this deep space mission scenario. The focus of this research is on optical communications. There are several problems associated with asteroid sensing, this thesis also considers solutions for some problems.


Last Updated: August 3, 2007