Lessons learned from the autonomous power system

The autonomous power system (APS) project at the NASA Lewis Research Center is described. The project is designed to demonstrate the applications of integrated intelligent diagnosis, control, and scheduling techniques to space power distribution systems. It consists of the autonomous power expert system (APEX) for fault detection, isolation, and recovery; the autonomous intelligent power scheduler, for efficient assignment of activity start times and resources; and power hardware (Brassboard) to emulate a space-based power system. Each part of the system was critiqued based on individual performance as well as the ability to interact with the other portions of the APS project. These critiques were used to determine guidelines for new and improved components     

Phase quantized SAR signal processing: theory and experiments

A complete theory of synthetic aperture radar (SAR) processing from phase-only data is presented, for both analogue and coded raw signals and reference functions. Appropriate processing architectures are presented as well as quality indexes to judge performance of the selected coding. The analysis encompasses both images and interferometric fringes for interferometry SAR (IFSAR) application. Theoretical results are validated by a large number of experiments, comparing the performance of the suggested coding levels, and their combinations between raw and reference functions. Experiments are extended until the comparison of final digital elevation models