Results 11 to 20 of about 318 (178)
Space Weather, 2023 We examine the accuracy of density prediction by the first principles model Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) developed by the National Center for Atmospheric Research and compare it to the accuracy of three ...
R. L. Walterscheid +5 more
doaj +2 more sources
Data‐Driven Satellite Drag Modeling Without Dynamic Knowledge of the Atmosphere
Space WeatherIncreasing congestion in low Earth orbit (LEO) from new satellite deployments and a growing debris population has made accurate orbital trajectory prediction essential for anticipating and avoiding potential collisions on a regular basis.
William E. Parker, Richard Linares
doaj +2 more sources
Encoding Cumulation to Learn Perturbative Nonlinear Oscillatory Dynamics. [PDF]
Adv Sci (Weinh)Weak nonlinearities critically shape the long term behavior of oscillatory systems but are difficult to identify from data. A data‐driven framework is introduced to infer governing equations of weakly nonlinear oscillators from sparse and noisy observations.
Ma T +5 more
europepmc +2 more sources
Fuel-Optimal Altitude Maintenance of Low-Earth-Orbit Spacecrafts by Combined Direct/Indirect Optimization [PDF]
Journal of Astronomy and Space Sciences, 2015 This work presents fuel-optimal altitude maintenance of Low-Earth-Orbit (LEO) spacecrafts experiencing non-negligible air drag and J2 perturbation.
Kyung-Ha Kim +2 more
doaj +1 more source
Design of Novel Laser Crosslink Systems Using Nanosatellites in Formation Flying: The VISION
Aerospace, 2022 With growth in data volume from space missions, interest in laser communications has increased, owing to their importance for high-speed data transfer in the commercial and defense fields, spaceborne remote sensing, and surveillance.
Geuk-Nam Kim +10 more
doaj +1 more source
Performance Comparison of the Batch Filter Based on the Unscented Transformation and Other Batch Filters for Satellite Orbit Determination [PDF]
Journal of Astronomy and Space Sciences, 2009 The main purpose of the current research is to introduce the alternative algorithm of the non-recursive batch filter based on the unscented transformation in which the linearization process is unnecessary.
Eunseo Park +2 more
doaj +1 more source
The Earth-Moon Transfer Trajectory Design and Analysis using Intermediate Loop Orbits [PDF]
Journal of Astronomy and Space Sciences, 2009 Various Earth-Moon transfer trajectories are designed and analyzed to prepare the future Korea's Lunar missions. Minimum fuel trajectory solutions are obtained for the departure year of 2017, 2020, 2022, and every required mission phases are analyzed ...
Young-Joo Song +4 more
doaj +1 more source
Unscented KALMAN Filtering for Spacecraft Attitude and Rate Determination Using Magnetometer [PDF]
Journal of Astronomy and Space Sciences, 2009 An Unscented Kalman Filter (UKF) for estimation of the attitude and rate of a spacecraft using only magnetometer vector measurement is developed. The attitude dynamics used in the estimation is the nonlinear Euler`s rotational equation which is augmented
Sung-Woo Kim +3 more
doaj +1 more source
Stellar Source Selections for Image Validation of Earth Observation Satellite [PDF]
Journal of Astronomy and Space Sciences, 2011 A method of stellar source selection for validating the quality of image is investigated for a low Earth orbit optical remote sensing satellite. Image performance of the optical payload needs to be validated after its launch into orbit.
Jiwoong Yu +4 more
doaj +1 more source
Geophysical Research Letters, Volume 50, Issue 17, 16 September 2023., 2023 Abstract Significant imbalances in terrestrial water storage (TWS) and severe drought have been observed around the world as a consequence of climate changes. Improving our ability to monitor TWS and drought is critical for water‐resource management and water‐deficit estimation.
Shuo Zhang +4 more
wiley +1 more source