The Low Fuel Consumption Keeping Method of Eccentricity under Integrated Keeping of Inclination-Longitude

Abstract

The influence of the natural perturbation force will cause the eccentricity of the GEO satellite to produce a periodic motion with a period of years, and then cause the east–west station of the GEO satellite to oscillate. From the perspective of the best fuel-saving or the failure of the thruster used for station keeping, some scholars have proposed a method of slightly deflecting the thrust used for north–south station keeping (NSSK) to the east or west to achieve the integrated keeping of inclination and longitude. The disadvantage of this strategy is that the eccentricity cannot be maintained, and even causes the continuous divergence of the eccentricity. Based on the above problems, this paper proposes a low fuel consumption keeping method for eccentricity under the integrated maintenance of inclination and longitude. Assuming that the satellite is only equipped with a south (north) direction thruster for station keeping, on the premise of not affecting the satellite’s Earth observation, the satellite’s forward flight and backward flight are switched every year at the spring equinox and autumn equinox, which can prevent the eccentricity divergence when performing mean longitude keeping. When the accuracy of the east–west station keeping is not pursued, this method can not only effectively save the fuel consumption of the station keeping, but also greatly reduce the number of eccentricity maintenance interventions and the interference to the whole satellite due to the eccentricity keeping, which has a certain engineering application value.

The Angular Momentum Unloading of the Asymmetric GEO Satellite by Using Electric Propulsion with a Mechanical Arm

“…In the nominal coordinate system, the three-axis attitude of the satellite is the corresponding nominal forward or backward flight attitude. Therefore, angular momentum unloading can be accomplished by executing the SK strategy [16][17][18] in the nominal coordinate system. The conversion matrix from the nominal coordinate system to the satellite body coordinate system is the conversion matrix of the satellite attitude offset.…”

“…As a result, the loss of SK efficiency due to angular momentum unloading is at most 0.4%. According to the literature [16][17][18], the annual speed increment required for SK does not exceed 50 m/s. As a result, the required velocity increment for angular momentum unloading is less than 0.2 m/s per year.…”

“…In the literature [16][17][18], we have studied the NSSK (north-south station keeping, NSSK) and EWSK (east-west station keeping, EWSK) of GEO satellites by using a mechanical arm and EP. This paper uses the mechanical arm to adjust the position and attitude of thrust generated during SK, and the three-axis large angular momentum unloading of asymmetrical satellite is realized.…”