The Spacecraft Autonomous Navigation System using GPS for Earth Orbiters (SANS-GEO) computer program is designed to perform the navigation calculations that will enable the New Millennium Program's Earth Orbiter-1 (EO-1) spacecraft to fly in formation with the Landsat-7 (LS-7) satellite in orbit around the Earth. Scheduled to be launched in May 1999, the EO-1 will be required to follow 450±50 km behind the LS-7, and to keep its ground track within 3 km of the LS-7 ground track. Using data from an onboard Global Positioning System (GPS) receiver and empirical (purely kinematic) GPS navigation algorithms, SANS-GEO would compute parameters of the EO-1 orbit; these parameters would include rates of atmospheric-drag-induced decay. SANS-GEO would then utilize these parameters, along with the corresponding parameters and with maneuver plans generated remotely for the LS-7, to determine EO-1 velocity-change maneuvers needed to satisfy absolute orbital constraints (e.g., ground-track-repeat requirements) and/or relative orbital constraints (formation-flying requirements). The computed velocity-change maneuvers would be converted into commands for the EO-1 attitude-control system and thrusters.
This program was written by Joseph Guinn of Caltech for NASA's Jet Propulsion Laboratory.
This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393-3425. Refer to NPO-20190.
This Brief includes a Technical Support Package (TSP).
Software for navigation of a spacecraft flying in formation
(reference NPO20190) is currently available for download from the TSP library.
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Overview
The document outlines a technical support package related to the development of software for the autonomous navigation of spacecraft flying in formation, specifically focusing on the EO-1 (Earth Observing-1) satellite. Invented by Joseph R. Guinn, this software is designed to enhance the navigation capabilities of the EO-1 as it operates in close proximity to the Landsat-7 satellite, which is crucial for Earth observation missions.
The EO-1 mission, scheduled for launch in May 1999, aims to demonstrate advanced technologies for future Earth observation satellites. The software utilizes Global Positioning System (GPS) technology to enable precise tracking and navigation, allowing the EO-1 to maintain a formation flying configuration with Landsat-7. This capability is significant for improving data collection and enhancing the quality of Earth observation imagery.
The document emphasizes the importance of autonomous navigation in formation flying, which reduces the need for constant ground control intervention and allows for more efficient mission operations. The software is designed to handle various navigation challenges, ensuring that the EO-1 can adapt to dynamic conditions in space.
Additionally, the document includes references to various studies and presentations related to formation flying and GPS technology, highlighting the collaborative efforts in the field of astrodynamics. It mentions previous works that have contributed to the understanding and implementation of GPS in spacecraft navigation, showcasing the evolution of technology in this area.
The technical support package also includes a disclaimer stating that neither NASA nor the U.S. government guarantees the accuracy or completeness of the information provided, nor do they assume liability for any damages resulting from the use of the information or methods disclosed.
Overall, the document serves as a comprehensive overview of the EO-1 autonomous navigation software, its objectives, and its significance in the context of Earth observation missions. It reflects NASA's commitment to advancing space technology and improving the capabilities of future satellite missions through innovative software solutions. The software is also noted to be available for commercial licensing, indicating potential applications beyond the EO-1 mission.
