Autonomous deep space navigation for two lunar spacecrafts from relative position measurements
- Paper number
IAC-06-A3.P.6.07
- Author
Mr. Ye Biao, Beijing University of Aeronautics and Astronautics, China
- Coauthor
Dr. Yang Bo, Beijing University of Aeronautics and Astronautics, China
- Year
2006
- Abstract
In general, orbit determination for a lunar-probe spacecraft involves measure -ments of range and range rate based on signals from Deep Space Network (DSN). However, there are some problems in this process, such as the shortness of base line and signals’ delay. In section 1 of this paper a new navigation scenario has been designed and analyzed to autonomously determine the orbits of two spacecrafts during they run around the moon, based on measurements of the relative positions vector from one spacecraft to the other. Before it works, the new system needs another simple but quick-converse algorithm based on measuring the direction to the center of moon to limit their initial covariance of orbits into available ranges.All of the sensors for the proposed system could reside on one of the two spacecrafts. The spacecraft with sensors will need a 3-axis star sensor system to determine its inertial attitude. It will also need instrumentation to measure the position vector of the other spacecraft in its own spacecraft-fixed reference frame.In section 2, the proposed system model (include the dynamic orbital model and measurement model) and the Unscented Kalman Filter (UKF) design will be mentioned. For getting more accurate results, UKF estimates the 6-element orbital state vectors of both spacecrafts, rather than their range and range rate vectors. Section 3 presents two critical issues with their resolutions for the proposed system.1)If the two orbital planes drift at the same pace (the same direction and magnitude), the states of the two spacecraft will be unobservable, with the only measurement data came from the two spacecrafts’ position. For that reason, it’s necessary to bring some additional measurement data that is out of the two spacecraft’s system to resolve this problem, and how to choose is the principal component of this paper.2)In usual, the orbital periods are not equal. In that case, it is possible that the two spacecrafts are unable to acquire the measurement data from each other, when on opposite sides of the moon. Thus, how to resolve this problem is important. Section 4 gives the simulation process of the proposed system and some initial data for UKF operation.Section 5 analyses the covariance variations for two lunar spacecrafts’ orbits in four cases. Section 6 presents the conclusion of this paper and discusses some issues needed to consider associated with this system in next research.
- Abstract document
- Manuscript document
IAC-06-A3.P.6.07.pdf (🔒 authorized access only).
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