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E-2. Attitude Analysis Assumptions

This architecture assumes a fairly comprehensive attitude capability which can perform sensor data processing, attitude determination, attitude ephemeris and events generation, and attitude anomaly detection. Data flows provide a logical breakdown of functionality and the performance benchmarks provide evidence supporting the allocation made in the hardware architecture in the main report.

The real-time or non-real-time nature of the Attitude Analysis process is not specifically addressed in this architecture. The only aspect of this architecture that tends toward the non-real-time mode is that certain interfaces are handled through data stores rather than real-time message passing. There should be little difference in the material presented for the two modes of operations.

The capability to determine a spacecraft's attitude will be used to support those activities associated with satellite attitude determination and ephemeris propagation. This must be done for operational modes encountered during the launch and early orbit operational phase of a satellite's mission as well as the mission operations phase. Typically, a satellite's inertial attitude is determined using observation data from a group of onboard sensors along with the spacecraft's orbital ephemeris.

The capability to predict sensor data as well as determination of antenna transmission angles is available with the products associated with Attitude Ephemeris and Events.

Information associated with the spacecraft's mass properties and spin speed may be derived from the telemetry data stream and processed with the observed attitude data available from the attitude (Earth, sun, stellar) sensors.

The capability to define the knowledge base for managing anomaly detection and anomaly resolution will depend on mission-unique data representing a satellite's attitudinal state as well as the sequence and magnitude of spin precession maneuvers planned for a mission.