{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:51:55Z","timestamp":1760241115898,"version":"build-2065373602"},"reference-count":31,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2019,11,30]],"date-time":"2019-11-30T00:00:00Z","timestamp":1575072000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100007263","name":"Virginia Polytechnic Institute and State University","doi-asserted-by":"publisher","award":["N\/A"],"award-info":[{"award-number":["N\/A"]}],"id":[{"id":"10.13039\/100007263","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000181","name":"Air Force Office of Scientific Research","doi-asserted-by":"publisher","award":["13-0658-09"],"award-info":[{"award-number":["13-0658-09"]}],"id":[{"id":"10.13039\/100000181","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The Virginia Tech Formation Flying Testbed (VTFFTB) is a global navigation satellite system (GNSS)-based hardware-in-the-loop (HIL) simulation testbed for spacecraft formation flying with ionospheric remote sensing applications. Past applications considered only the Global Positioning System (GPS) constellation. The rapid GNSS modernization offers more signals from other constellations, including the growing European system\u2014Galileo. This study presents an upgrade of VTFFTB with the incorporation of Galileo and the associated enhanced capabilities. By simulating an ionospheric plasma bubble scenario with a pair of LEO satellites flying in formation, the GPS-based simulations are compared to multi-constellation GNSS simulations including the Galileo constellation. A comparison between multi-constellation (GPS and Galileo) and single-constellation (GPS) shows the absolute mean and standard deviation of vertical electron density measurement errors for a specific Equatorial Spread F (ESF) scenario are decreased by 32.83% and 46.12% with the additional Galileo constellation using the 13 July 2018 almanac. Another comparison based on a simulation using the 8 March 2019 almanac shows the mean and standard deviation of vertical electron density measurement errors were decreased further to 43.34% and 49.92% by combining both GPS and Galileo data. A sensitivity study shows that the Galileo electron density measurements are correlated with the vertical separation of the formation configuration. Lower C\/N     0     level increases the measurement errors and scattering level of vertical electron density retrieval. Relative state estimation errors are decreased, as well by utilizing GPS L1 plus Galileo E1 carrier phase instead of GPS L1 only. Overall, superior performance on both remote sensing and relative navigation applications is observed by adding Galileo to the VTFFTB.<\/jats:p>","DOI":"10.3390\/rs11232851","type":"journal-article","created":{"date-parts":[[2019,12,2]],"date-time":"2019-12-02T10:50:45Z","timestamp":1575283845000},"page":"2851","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Satellite Formation Flight Simulation Using Multi-Constellation GNSS and Applications to Ionospheric Remote Sensing"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1089-1121","authenticated-orcid":false,"given":"YuXiang","family":"Peng","sequence":"first","affiliation":[{"name":"Center for Space Science and Engineering at Virginia Tech, Corporate Research Center, 1341 Research Center Dr. Suite 1000, Blacksburg, VA 24061, USA"},{"name":"Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24061, USA"}]},{"given":"Wayne A.","family":"Scales","sequence":"additional","affiliation":[{"name":"Center for Space Science and Engineering at Virginia Tech, Corporate Research Center, 1341 Research Center Dr. Suite 1000, Blacksburg, VA 24061, USA"},{"name":"Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24061, USA"}]}],"member":"1968","published-online":{"date-parts":[[2019,11,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1003","DOI":"10.1126\/science.168.3934.1003","article-title":"Formation flight of birds","volume":"168","author":"Lissaman","year":"1970","journal-title":"Science"},{"key":"ref_2","unstructured":"Curtis, S. (1999). The Magnetospheric Multiscale Mission: Resolving Fundamental Processes in Space Plasmas: Report of the NASA Science and Technology Definition Team for the Magnetospheric Multiscale (MMS) Mission."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1126\/science.1099192","article-title":"GRACE measurements of mass variability in the Earth system","volume":"305","author":"Tapley","year":"2004","journal-title":"Science"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"210","DOI":"10.1016\/j.asr.2006.10.008","article-title":"Swarm\u2014An Earth observation mission investigating geospace","volume":"41","author":"Knudsen","year":"2008","journal-title":"Adv. Space Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1002\/j.2161-4296.2003.tb00320.x","article-title":"Demonstration of Adaptive Extended Kalman Filter for Low-Earth-Orbit Formation Estimation Using CDGPS","volume":"50","author":"Busse","year":"2003","journal-title":"Navigation"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Mohiuddin, S., and Psiaki, M. (2005, January 15\u201318). Satellite relative navigation using carrier-phase differential GPS with integer ambiguities. Proceedings of the AIAA Guidance, Navigation, and Control Conference and Exhibit, San Francisco, CA, USA.","DOI":"10.2514\/6.2005-6054"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1303","DOI":"10.5194\/amt-9-1303-2016","article-title":"Statistical framework for estimating GNSS bias","volume":"9","author":"Vierinen","year":"2016","journal-title":"Atmos. Meas. Tech."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1175\/BAMS-89-3-313","article-title":"The COSMIC\/FORMOSAT-3 mission: Early results","volume":"89","author":"Anthes","year":"2008","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_9","unstructured":"Bishop, R., Hinkley, D., Stoffel, D., Ping, D., Straus, P., and Brubaker, T. (2012, January 13\u201316). First results from the GPS compact total electron content sensor (CTECS) on the PSSCT-2 nanosat. Proceedings of the AIAA\/Utah State University Conference on Small Satellites, Logan, UT, USA."},{"key":"ref_10","unstructured":"Spann, J., Swenson, C., Durao, O., Loures, L., Heelis, R., Bishop, R., Le, G., Abdu, M., Krause, L., and Fry, C. (2017, January 5\u201310). The scintillation prediction observations research task (SPORT): an international science mission using a cubesat. Proceedings of the AIAA\/Utah State University Conference on Small Satellites, Logan, UT, USA."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Bernhardt, P.A., and Siefring, C.L. (2006). New satellite-based systems for ionospheric tomography and scintillation region imaging. Radio Sci., 41.","DOI":"10.1029\/2005RS003360"},{"key":"ref_12","unstructured":"Hall, C., Davis, N., DeLaRee, J., Scales, W., and Stutzman, W. (1999, January 23\u201326). Virginia Tech Ionospheric Scintillation Measurement Mission. Proceedings of the AIAA\/Utah State University Conference on Small Satellites, Logan, UT, USA."},{"key":"ref_13","unstructured":"Leitner, J. (2001, January 10\u201317). A hardware-in-the-loop testbed for spacecraft formation flying applications. Proceedings of the IEEE Aerospace Conference Proceedings, Big Sky, MT, USA."},{"key":"ref_14","unstructured":"Gill, E., Naasz, B., and Ebinuma, T. (2003, January 5\u20139). First results from a hardware-in-the-loop demonstration of closed-loop autonomous formation flying. Proceedings of the 26th Annual AAS Guidance and Control Conference, Breckenridge, CO, USA."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Giralo, V., and D\u2019Amico, S. (2018, January 24\u201328). Distributed Multi-GNSS Timing and Localization for Nanosatellites. Proceedings of the ION GNSS+, Miami, FL, USA.","DOI":"10.33012\/2018.15979"},{"key":"ref_16","unstructured":"Eyer, J. (2009). A Dynamics and Control Algorithm for Low Earth Orbit Precision Formation Flying Satellites. [Ph.D. Thesis, University of Toronto]."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1451","DOI":"10.1016\/j.asr.2010.08.012","article-title":"Hardware-in-the-loop simulations of GPS-based navigation and control for satellite formation flying","volume":"46","author":"Park","year":"2010","journal-title":"Adv. Space Res."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Peng, Y., Scales, W., and Edwards, T.R. (2018, January 24\u201328). GPS-based Spacecraft Formation Flying Simulation and Applications to Ionospheric Remote Sensing. Proceedings of the ION GNSS+, Miami, FL, USA.","DOI":"10.33012\/2018.15858"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Cloutier, J.R. (1997, January 6). State-dependent Riccati equation techniques: An overview. Proceedings of the 1997 American Control Conference (Cat. No. 97CH36041), Albuquerque, NM, USA.","DOI":"10.1109\/ACC.1997.609663"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1007\/s10291-006-0029-5","article-title":"Automated GPS processing for global total electron content data","volume":"10","author":"Rideout","year":"2006","journal-title":"GPS Solut."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Ouassou, M., Kristiansen, O., Gjevestad, J.G., Jacobsen, K.S., and Andalsvik, Y.L. (2016). Estimation of scintillation indices: A novel approach based on local kernel regression methods. Int. J. Navig. Obs.","DOI":"10.1155\/2016\/3582176"},{"key":"ref_22","unstructured":"Kelley, M.C. (2009). The Earth\u2019s Ionosphere: Plasma Physics and Electrodynamics, Academic Press."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"324","DOI":"10.1109\/PROC.1982.12313","article-title":"Radio wave scintillations in the ionosphere","volume":"70","author":"Yeh","year":"1982","journal-title":"Proc. IEEE"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"788","DOI":"10.1016\/j.asr.2004.12.076","article-title":"The ionosphere, radio navigation, and global navigation satellite systems","volume":"35","author":"Kintner","year":"2005","journal-title":"Adv. Space Res."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Rodrigues, F., De Paula, E., Abdu, M., Jardim, A., Iyer, K., Kintner, P., and Hysell, D. (2004). Equatorial spread F irregularity characteristics over Sao Luis, Brazil, using VHF radar and GPS scintillation techniques. Radio Sci., 39.","DOI":"10.1029\/2002RS002826"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2411","DOI":"10.1029\/JA086iA04p02411","article-title":"Simultaneous rocket-borne beacon and in situ measurements of equatorial spread F\u2014Intermediate wavelength results","volume":"86","author":"Rino","year":"1981","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1007\/s10291-013-0336-6","article-title":"Ionospheric threat simulation for GNSS using the Spirent hardware signal simulator","volume":"18","author":"Dautermann","year":"2014","journal-title":"GPS Solut."},{"key":"ref_28","unstructured":"Peng, S. (2012). A Multi-Constellation Multi-Frequency GNSS Software Receiver Design for Ionosphere Scintillation Studies. [Ph.D. Thesis, Faculty of theVirginia Polytechnic Institute and State University]."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Morton, Y., Bourne, H., Carroll, M., Jiao, Y., Kassabian, N., Taylor, S., Wang, J., Xu, D., and Yin, H. (2014, January 16\u201323). Multi-constellation GNSS observations of equatorial ionospheric scintillation. Proceedings of the 2014 XXXI URSI General Assembly and Scientific Symposium (URSI GASS), Beijing, China.","DOI":"10.1109\/URSIGASS.2014.6929773"},{"key":"ref_30","unstructured":"Morton, Y., Jiao, Y., van Graas, F., Vinande, E., and Pujara, N. (2015, January 20\u201323). Analysis of receiver multi-frequency response to ionospheric scintillation in Ascension Island, Hong Kong, and Singapore. Proceedings of the ION PNT, Honolulu, HI, USA."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Shanmugam, S., Jones, J., MacAulay, A., and Van Dierendonck, A. (2012, January 23\u201326). Evolution to modernized GNSS ionoshperic scintillation and TEC monitoring. Proceedings of the 2012 IEEE\/ION Position, Location and Navigation Symposium, Myrtle Beach, SC, USA.","DOI":"10.1109\/PLANS.2012.6236891"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/23\/2851\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:38:59Z","timestamp":1760189939000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/23\/2851"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,11,30]]},"references-count":31,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2019,12]]}},"alternative-id":["rs11232851"],"URL":"https:\/\/doi.org\/10.3390\/rs11232851","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2019,11,30]]}}}