Study of Some Strategies for Disposal of the GNSS Satellites

Diogo Merguizo Sanchez,Tadashi Yokoyama,Antonio Fernando Bertachini De Almeida Prado

doi:10.1155/2015/382340

Abstract

The complexity of the GNSS and the several types of satellites in the MEO region turns the creation of a definitive strategy to dispose the satellites of this system into a hard task. Each constellation of the system adopts its own disposal strategy; for example, in the American GPS, the disposal strategy consists in changing the altitude of the nonoperational satellites to 500 km above or below their nominal orbits. In this work, we propose simple but efficient techniques to discard satellites of the GNSS by exploiting Hohmann type maneuvers combined with the use of the2ω˙+Ω˙≈0resonance to increase its orbital eccentricity, thus promoting atmospheric reentry. The results are shown in terms of the increment of velocity required to transfer the satellites to the new orbits. Some comparisons with direct disposal maneuvers (Hohmann type) are also presented. We use the exact equations of motion, considering the perturbations of the Sun, the Moon, and the solar radiation pressure. The geopotential model was considered up to order and degree eight. We showed the quantitative influence of the sun and the moon on the orbit of these satellites by using the method of the integral of the forces over the time.

Highlights

Global navigation satellite systems are a general denomination for constellations of navigation satellites, such as GPS (USA), GLONASS (Russia), Galileo (Europe), and Beidou (China), mainly placed in the medium earth orbit (MEO) region
We focus on the use of the strategy of eccentricity growth under the effect of the 2 : 1 perigeeascending node resonance, which leads to the atmospheric reentry, and we compare this strategy with the direct discard using a Hohmann type transfer
In order to ensure that the method of increasing the apoapsis radius to enhance the effect of the 2 : 1 perigeeascending node resonance works for all the satellites of the GNSS with inclination around 56∘, we present Figure 11, which show a satellite of the Galileo system (US catalog 28922) with a semimajor axis so that its apoapsis radius has 10,000 km above the nominal value

Summary

Introduction

Global navigation satellite systems are a general denomination for constellations of navigation satellites, such as GPS (USA), GLONASS (Russia), Galileo (Europe), and Beidou (China), mainly placed in the medium earth orbit (MEO) region. From the analysis of the initial conditions which lead to the previously mentioned instability caused by the 2 : 1 perigee-ascending node resonance, some works suggest moving the disposed satellites to regions such that the growth of the eccentricity does not allow the disposed satellites to invade the region of the operational satellites, at least for some acceptable time This strategy may present some inconveniences, such as an accumulation of objects in the disposal region. It is worth noting that if the semimajor axis is high, the effect of the moon cannot be neglected, so that the problem is no more a one degree of freedom problem In this case the search of the (ω, Ω) pair such that the eccentricity increases must be done by integrating the complete equations of motion. We will consider this criterion in the search of initial conditions that causes an increase in the eccentricity

Initial Conditions for the Strategy of Increasing the Eccentricity

The Direct Deorbiting Compared with the Disposal via Resonance

Quantitative Analysis of the Perturbation of the Moon and the Sun

Conclusions