Fuzzy Feature Observation Planner for Small Body Proximity Observations (FuzzObserver) is a developmental computer program, to be used along with other software, for autonomous planning of maneuvers of a spacecraft near an asteroid, comet, or other small astronomical body. Selection of terrain features and estimation of the position of the spacecraft relative to these features is an essential part of such planning. FuzzObserver contributes to the selection and estimation by generating recommendations for spacecraft trajectory adjustments to maintain the spacecraft's ability to observe sufficient terrain features for estimating position. The input to FuzzObserver consists of data from terrain images, including sets of data on features acquired during descent toward, or traversal of, a body of interest. The name of this program reflects its use of fuzzy logic to reason about the terrain features represented by the data and extract corresponding trajectory-adjustment rules. Linguistic fuzzy sets and conditional statements enable fuzzy systems to make decisions based on heuristic rule-based knowledge derived by engineering experts. A major advantage of using fuzzy logic is that it involves simple arithmetic calculations that can be performed rapidly enough to be useful for planning within the short times typically available for spacecraft maneuvers.
This program was written by Ayanna Howard and David Bayard of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Software category.
This software is available for commercial licensing. Please contact Karina Edmonds of the California Institute of Technology at (818) 393-2827. Refer to NPO-41290.
This Brief includes a Technical Support Package (TSP).
FuzzObserver
(reference NPO-41290) is currently available for download from the TSP library.
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Overview
The document discusses the development of FuzzObserver, an autonomous system designed to enhance spacecraft operations during small body proximity missions. Developed at NASA's Jet Propulsion Laboratory, FuzzObserver utilizes fuzzy logic to maintain surface feature references within the sensor view of a spacecraft. This capability is crucial for improving the reliability of position estimation as the spacecraft descends towards small celestial bodies.
FuzzObserver operates by recommending trajectory adjustments based on a set of predefined criteria that assess the satisfaction of feature selection rules. These criteria are categorized into four main areas: Quality, Quantity, Closeness, and Cluster. Each criterion is evaluated using a linguistic fuzzy set that assigns satisfaction levels of POOR, GOOD, or EXCELLENT, with corresponding numerical values ranging from 0 to 1. For instance, a higher quantity of features in a specified region is preferred, as it increases the likelihood of successful feature matching in subsequent images.
The document outlines the implementation of FuzzObserver within a Small Body Descent Simulator, demonstrating its effectiveness in maintaining surface feature references during descent sequences. The system's ability to adaptively recommend trajectory adjustments based on the satisfaction of the four criteria allows for consistent updates of feature observations, thereby enhancing the spacecraft's navigation capabilities.
Future work aims to integrate FuzzObserver directly into a Guidance, Navigation, and Control (GN&C) simulation system, which will further document its performance in improving position estimation during small body operations. The research is supported by NASA's internal Research and Development program and highlights the potential for broader applications of fuzzy logic in autonomous systems.
Overall, the document emphasizes the innovative approach taken by the Jet Propulsion Laboratory in utilizing fuzzy logic for autonomous spacecraft operations, showcasing the potential for improved mission success rates in challenging environments. The integration of FuzzObserver represents a significant advancement in the field of aerospace technology, with implications for future exploration missions to asteroids and other small celestial bodies.
