We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
A Simple Method for Correcting Empirical Model Densities During Geomagnetic Storms Using Satellite Orbit Data.
- Authors
Brandt, Daniel A.; Bussy‐Virat, Charles D.; Ridley, Aaron J.
- Abstract
Empirical models of the thermospheric density are routinely used to perform orbit maintenance, satellite collision avoidance, and estimate time and location of re‐entry for spacecraft. These models have characteristic errors in the thermospheric density below 10% during geomagnetic quiet time but are unable to reproduce the significant increase and subsequent recovery in the density observed during geomagnetic storms. Underestimation of the density during these conditions translates to errors in orbit propagation that reduce the accuracy of any resulting orbit predictions. These drawbacks risk the safety of astronauts and orbiting spacecraft and also limit understanding of the physics of thermospheric density enhancements. Numerous CubeSats with publicly available ephemeris in the form of two‐line element (TLEs) sets orbit in this region. We present the Multifaceted Optimization Algorithm (MOA), a method to estimate the thermospheric density by minimizing the error between a modeled trajectory and a set of TLEs. The algorithm first estimates a representative cross‐sectional area for several reference CubeSats during the quiet time 3 weeks prior to the storm, and then estimates modifications to the inputs of the NRLMSISE‐00 empirical density model in order to minimize the difference between the modeled and TLE‐provided semimajor axis of the CubeSats. For validation, the median value of the modifications across all CubeSats are applied along the Swarm spacecraft orbits. This results in orbit‐averaged empirical densities below 10% error in magnitude during a geomagnetic storm, compared to errors in excess of 25% for uncalibrated NLRMSISE‐00 when compared to Swarm GPS‐derived densities. Plain Language Summary: Empirical atmospheric density models underestimate the increase in thermospheric density observed during times of intense solar and geomagnetic activity. This demonstrates our limited understanding of the physics of the thermosphere during these times and limits our ability to accurately predict the orbits of both operational satellites and space debris. We present a method to correct these density underestimations by using an orbital propagator and correcting the inputs to the NRLMSISE‐00 density model to minimize orbit error. We apply medians of these adjustments along the orbit of the Swarm spacecraft and compare resulting corrected densities to GPS‐derived densities collected by Swarm. Key Points: Empirical atmospheric models exhibit significant density underestimation during geomagnetic stormsA simple algorithm presents a new way of obtaining improved density model estimates from two‐line elements describing satellite orbitsThe technique is validated against Swarm GPS‐derived densities during geomagnetic quiet and active times
- Subjects
MAGNETIC storms; THERMOSPHERE; ATMOSPHERIC density; GEOMAGNETISM; ORBITAL assembly of space vehicles
- Publication
Space Weather: The International Journal of Research & Applications, 2020, Vol 18, Issue 12, p1
- ISSN
1539-4956
- Publication type
Article
- DOI
10.1029/2020SW002565