Page:Advanced Automation for Space Missions.djvu/35

 USER REQUESTED DATA ABSTRACTED DATA

identify undergo close human scrutiny - if subsequently identified, the expected anomaly/action file is updated; if not, the event is catalogued and correlated with other similar but also unidentified anomalies. Identified anomalies keyed to time of occurrence, intensity, and other important parameters are archived and used to update the world model if necessary. Data abstracted from observed features are archived and used for world model updating. Information gathered in response to user requests is transmitted to customers for their exclusive use and is not automatically stored by the system.

2.4 Autonomous Satellites

This section focuses on individual satellites and the collective IESIS system, as suggested in figure 2.13. To satisfy overall IESIS goals, all satellites must be equipped with an appropriate ensemble of sensors and reside in orbits providing sufficiently frequent observation opportunities for all points of interest. Just as important, however, is the ability of each device to accept brief high-level instructions to guide its observations, and to perform massive onboard processing for abstraction of high-level information.

2.4.1 Onboard Processing

The observing satellite receives the schedule for its next pass from the uplink (section 2.4.2) and performs the requisite processing according to this instruction set. Terrestrial cloud cover and weather conditions are obtained from one of the IESIS geostationary satellites and navigational data are transmitted from a global positioning system already in place. Each satellite adjusts its attitude as required, turns detectors on and off, modifies sensor resolution, and takes both active and passive observations of the Earth. Data then are processed by comparison to predicted observables as derived from the world model.