Авіаційно-космічна техніка та технологія (Oct 2021)
Estimation of the influence of errors of the SINS constructed on MEMS components on the accuracy of positioning a ultra-light class rocket
Abstract
The object of the article is the movement of an ultra-light class liquid-propellant launch vehicle in near-earth space. The subject of the research is the accuracy of launching a spacecraft by a launch vehicle. The article studies the effect of errors in the instruments of a strap-down inertial navigation system built with the use of MEMS sensors on the accuracy of launching a spacecraft into low-earth orbits with an altitude of up to 450 km for two modes of operation: with and without a satellite navigation system. Tasks: to identify the determining disturbing factors, to determine the influence of instrument errors on the trajectory tube, to determine the influence of instrument errors on the insertion accuracy, to perform a comparative analysis of the accuracy characteristics obtained for two modes of operation of the navigation system. Methods used analysis, synthesis, analogy, comparison, factor analysis, statistical modeling, statistical processing of modeling results. Results: a set of defining disturbing factors was revealed, the dependencies of the trajectory tubes on the altitude of the target orbit and flight time were obtained, the dependencies of the limiting deviations of the parameters of the spacecraft's orbit at the time of separation from the launch vehicle on the altitude of the target orbit were obtained. Conclusions. 1. It is shown that the determining perturbing factors are the zero drift of the gyroscope from launch to launch and the zero random drift of the gyroscope. 2. It was determined that the value of the trajectory tube monotonically expands on time and the height of the target orbit. Maximum deviations of the current position and absolute speed in the mode without using a satellite navigation system do not exceed 115 km and 140 m/s. For the mode using a satellite navigation system, these values do not exceed 140 m and 1.5 m/s. 3. It was revealed that the maximum deviations of the parameters of the spacecraft's orbit in the mode with the use of a satellite navigation system do not exceed 27 km in height, 1.8o in inclination, 4.5x10-4 in eccentricity, and 2.7o for the longitude of the ascending node. For the mode with a satellite navigation system - in height - 2.6 km, in inclination and longitude of the ascending node - 0.0003о, in eccentricity - 3.5x10-4. 4. Generally, the use of a satellite navigation system narrows the trajectory tube by twice, and the accuracy increases to four times, depending on the orbital parameters.
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