Citation: Hu, M.; Ruan, Y.; Zhou, H.;
Xu, J.; Xue, W. Long-Term Orbit
Prediction and Deorbit Disposal
Investigation of MEO Navigation
Satellites. Aerospace 2022, 9, 266.
https://doi.org/10.3390/
aerospace9050266
Academic Editor: Kamil Krasuski
Received: 10 March 2022
Accepted: 12 May 2022
Published: 15 May 2022
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Article
Long-Term Orbit Prediction and Deorbit Disposal Investigation
of MEO Navigation Satellites
Min Hu
1,
*, Yongjing Ruan
1
, Huifeng Zhou
2
, Jiahui Xu
1
and Wen Xue
1
1
Department of Aerospace Science and Technology, Space Engineering University, Beijing 101416, China;
18970094850@163.com (Y.R.); xujiahui8_1@163.com (J.X.); xw159357007@163.com (W.X.)
2
Xichang Satellite Launch Center, Xichang 615000, China; zhouhuifeng_82@163.com
* Correspondence: jlhm09@163.com; Tel.: +86-13699263708
Abstract:
With the increase in satellites in the medium Earth orbit (MEO) region, there should be
a focus on orbit safety in the MEO region. A safe orbit disposal strategy is necessary to maintain
the sustainability of the MEO region. This paper focuses on long-term evolution modeling, safety
analysis of MEO objects, and different disposal techniques for end-of-life BDS-2 MEO satellites. On
the one hand, a long-term numerical evolution model is established, and mean equinoctial elements
are adopted to propagate a long-term orbit. Long-term evolution for the MEO region over 100 years
is carried out, including the Galileo, BDS, GPS, and GLONASS constellations. The earliest orbit
intersection time with other global navigation satellite system (GNSS) constellations is put forward.
On the other hand, a dynamic model and an optimization model for disposal orbit are established,
which minimize the eccentricity growth within 200 years and the fuel consumption for maneuvering
to the disposal orbit. The bounds for the disposal region of BDS MEO satellites are also proposed,
which consider the measurement and control error of BDS MEO satellites and the eccentricity bounds
for end-of-life BDS MEO satellites. A genetic algorithm is adopted to optimize the orbital elements
for end-of-life BDS MEO satellites. In addition, two disposal cases, namely, upraising and reducing
the orbit, for end-of-life BDS MEO satellites are simulated. The long-term evolutions for the disposal
of orbital elements within 200 years are implemented, and the fuel consumption is calculated. The
results show that the current MEO region is relatively safe and that the eccentricity is the most
important factor that influences the long-term evolution of safety analysis for BDS MEO disposal
orbits. Upraising the orbit is safe for end-of-life BDS MEO satellites. This investigation provides the
theoretical foundation for investigating the long-term evolutionary mechanisms of the MEO region
and references disposal strategy analysis for decommissioned navigation satellites, and the spent
upper stages for other GNSS constellations.
Keywords:
long-term evolution; MEO region; equinoctial elements; orbit intersection; BDS; MEO
satellite; disposal orbit
1. Introduction
Medium Earth orbit (MEO) is mainly used for satellite navigation nowadays. With
the modernization of GPS and GLONASS and the construction of BDS and Galileo, an
increasing number of satellites are launched into the MEO region. In the meantime, de-
commissioned navigation satellites and spent upper stages are left in the MEO region.
The MEO region will be considerably congested. For the orbit of space debris, including
decommissioned navigation satellites and spent upper stages in the MEO region, changes
over hundreds of years under perturbation forces may lead to many orbit intersections
with the global navigation satellite system (GNSS) orbit region. This may raise the collision
probability of the MEO region.
Based on up-to-date data(as of 1 May 2022) [
1
], 32 GPS satellites are in orbit, including
seven GPS II-R satellites, eight GPS IIR-M satellites, 12 GPS II-F satellites, and five GPS
Aerospace 2022, 9, 266. https://doi.org/10.3390/aerospace9050266 https://www.mdpi.com/journal/aerospace
