| The Lunar Lander is the most effective way to explore Lunar. The landing point position is inevitably biased after arrival in Lunar, and the Lander attitude also need to be mansurated in time. INS carries cumulative errors because of the long time operation on lunar surface, so the position and orientation of the Lander must be provided again, and further to the INS initial alignment and inertial devices error calibration using external navigation information.Considering the special circumstances of Lunar, an approach satisfing the requirements of precise positioning, which is based on VLBI and autonomous to determine the Lander position and takes into account the accuracy, high reliability and strong astronomical features is proposed in this paper. Ground-based monitoring system error can be reduced or eliminated by differential VLBI methods. Meanwhile, a program based on the current VLBI network of our country is presented in order to achieve the Lander accurate positioning.An approach of attitude determination using star sensors, a sun sensors and accelerometers is proposed in this paper. This program ensures the accuracy and reliability, with a good engineering reference.Considering the lunar local level coordinate system as navigation system, this paper first gets a small Lander attitude misalignment angle through the initial lunar base self-aligned static method, establishes the first order error model of INS and inertial device under the conditions of lunar stationary base, and then makes the model as the equation of state, the velocity output of INS working on stationary base as the measurement equation to design Kalman filter. Through the Kalman filter algorithm to estimate the Lander misalignment angle error and the random constant inertial errors, and then to achieve the target of INS initial alignment and inertial device calibration. The simulation results with high accuracy show that the program is suitable for the alignment and calibration requirements. |
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