SwARM: Software for Absolute and Relative Motion (Satellite Theories)

Author: Bharat Mahajan
https://github.com/princemahajan

SwARM is a second-order analytic propagator for absolute (or relative to a central gravitational body) and relative (i.e., relative to another satellite in orbit) motion of satellites in the presence of zonal, sectorial, and tesseral gravitational harmonic perturbations. 

GUI screenshot: SwARMGUI.png

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Tips
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Provide all the required filenames with complete paths. Use '\\' as the path separator. 

For GMAT, use correct GMAT working directory path in "GMAT Working Dir" textbox. SwARM needs it to be able to find the GMAT propagation result files (ChiefStates.txt, DepStates.txt, ChiefOE.txt, DepOE.txt), which are created by the GMAT script, in the GMAT_Working_Dir\\output folder. 

"MAT Results File" is the name of a file the user must provide, in which the propagation results are stored. The values of the "Gravitational Parameter" and "Radius" must match the gravity model provided by the "Gravity Coefficient File."

If the code gives an error due to MEX files, then uncheck the "Use J2 MEX Code" checkbox. In case of some other error, try restarting the application. As a last resort, unpack the source code from the SwARM.mlapp app file and run the codes manually by execuing the file 'SwARMmain.m' in MATLAB. For more details, see the help menu in the app. 

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Known Issues
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1. If the tesseral harmonics are enabled and the reference orbit (Chief's orbit) for formation flying has zero eccentricity or the inclination, then relative motion analytic propagation has singularity issues. However, there are no issues with any zonal harmonic.

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Research articles on which the code is based
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[0] Bharat Mahajan, S. R. Vadali, and K. T. Alfriend, “State-Transition Matrix for Satellite Relative Motion in the Presence of Gravitational Perturbations," Journal of Guidance, Control, and Dynamics, Volume 42, Number 7, July 2019. https://doi.org/10.2514/1.G004133

[1] Mahajan, B., "Absolute and Relative Motion Satellite Theories for Zonal and Tesseral Gravitational Harmonics," PhD Dissertation, Texas A&M University, 2018.

[2] Mahajan, B., Vadali, S.R. & Alfriend, K.T. Celest Mech Dyn Astr (2018) 130: 25. https://doi.org/10.1007/s10569-018-9818-8

[3] Bharat Mahajan, S. R. Vadali, and K. T. Alfriend, “Analytic solution of perturbed relative motion with zonal and tesseral harmonics,” In J. W. McMahon, Y. Guo, F. A. Leve and J. A. Sims (Eds.), Spaceflight Mechanics 2017: Proceedings of the 27th AAS/AIAA Space Flight Mechanics Meeting, held February 5-9, 2017 San Antonio, Texas, U.S.A. (pp. 1117-1134). [AAS 17-475] (Advances in the Astronautical Sciences; Vol. 160). San Diego, California: Published for the American Astronautical Society by Univelt, Inc. (2017).


[4] Bharat Mahajan, S. R. Vadali, and K. T. Alfriend, “Exact normalization of the tesseral harmonics,” In J. W. McMahon, Y. Guo, F. A. Leve and J. A. Sims (Eds.), Spaceflight Mechanics 2017: Proceedings of the 27th AAS/AIAA Space Flight Mechanics Meeting, held February 5-9, 2017 San Antonio, Texas, U.S.A. (pp. 2569-2588). [AAS 17-473] (Advances in the Astronautical Sciences; Vol. 160). San Diego, California: Published for the American Astronautical Society by Univelt, Inc. (2017)


[5] Bharat Mahajan, S. R. Vadali, and K. T. Alfriend, “Analytic solution for satellite relative motion: The complete zonal gravitational problem,” In R. Zanetti, R. P. Russell, M. T. Ozimek and A. L. Bowes (Eds.), Spaceflight Mechanics 2016: Proceedings of the 26th AAS/AIAA Space Flight Mechanics Meeting, held February 14-18, 2016, Napa, California, U.S.A. (pp. 3325-3348). [AAS 16-262] (Advances in the Astronautical Sciences; Vol. 158). San Diego, California: Published for the American Astronautical Society by Univelt, Inc. (2016)


[6] Bharat Mahajan, S. R. Vadali, and K. T. Alfriend, “Analytic solution for satellite relative motion with zonal gravity perturbations,” In M. Majji, J. D. Turner, G. G. Wawrzyniak, and W. T. Cerven (Eds.), Astrodynamics 2015: Proceedings of the AAS/AIAA Astrodynamics Specialist Conference held August 9–13, 2015, Vail, Colorado, U.S.A. (pp. 3583-3598). [AAS 15-705] (Advances in Astronautical Sciences; Vol. 156). San Diego, California: Published for the American Astronautical Society by Univelt, Inc. (2016).


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LICENSE
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Copyright 2021 Bharat Mahajan (https://github.com/princemahajan)

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.