Study Of Liaision Autonomous Orbit Determination For Libration Point Satellites And Earth Navigation Satellites

Libration point orbits are important to deep space detecting tasks because of their special dynamics. Deep space navigation and communication is one of the most important applications of Lagrangian satellites development. Uniqueness of Lagrangian quasi-periodic orbit in both time and space is the theoretical basis of autonomous orbit determination of Lagrangian orbit satellite using only satellite-to-satellite tracking. In this essay one satellite on quasi-periodic orbit is selected from each libration point as a Lagrangian navigation constellation. State transition matrix and observation matrix of Lagrangian satellites are derived to establish a constellation autonomous orbit determination method based on satellite-to-satellite tracking in circular restricted three-body problem model and also elliptical restricted three-body problem model. Extended Kalman filter and uncented Kalman filter are used in simulation and the performances of these algorithms in strong nonlinear system i.e. three body problem model are compared. The simulation indicates that autonomous orbit determination of Lagrangian satellites using only satellite-to-satellite tracking can keep satellite position error from diverging within 180 days and error in x axis y axis can converge even initial state are not accurate.Lagrangian satellites can get absolute position information from satellite-to-satellite tracking data, which can help Lagrangian satellites autonomously determine their orbits using only satellite-to-satellite tracking, so it is theoretically acceptable to enable earth navigation satellites to get their absolute position by observing the distance to Lagrangian satellites. This article mainly talks about earth-moon system. The motion of Lagrangian satellites and the observation model between Lagrangian satellites and earth navigation satellites are described in centroid rotating coordinates while the motion of earth navigation satellites are shown in geocentric inertial coordinates so the transformation between the coordinates above is also stated. A combination method of autonomous orbit determination based on centralized data processing by combining Lagrangian satellites and earth navigation satellites observation data is established and it is necessary to acquire partial derivative of crosslink range i.e. the range between Lagrangian satellites and earth navigation satellites with respect to earth navigation satellites' orbital elements. 12 GPS satellites and 5 Lagrangian satellites are chosen for simulation. The most important purpose of the simulation is to verify the feasibility of this orbit determination method. A group of controlled experiments are designed to compare the spatial orientation based method and this combination method.Lagrangian satellites autonomous orbit determination simulation shows that autonomous orbit determination using only satellite-to-satellite tracking is valid for Lagrangian satellites, which is significant for improving the safety and autonomy of deep space probe. The outcomes of combination method simulation demonstrate that Lagrangian satellites can stop earth navigation satellites from position error divergence caused by constellation rotation so it is reasonable to make combination method an alternative, which can help guarantee the earth satellite navigation accuracy and stability.