Based on LOS method ,combined with DSMC, the particle clouds movement model and the optical radiation transmission model were established, the dynamic radiation performance and transmittance of particle clouds in space within medium wave and long wave were analyzed accordingly, the results showed that the heat flux in space has a certain influence on the particle clouds radiation, but not on the extinction obviously; when the number density of particle clouds was greater than 1x107 , the transmittance of particle clouds in medium wave and long wave was less than 10%.
High precision inertial navigation devices are required for high accuracy of on-orbit navigation of the aircraft, on the other side ,it will lead to the increasement of the cost. The paper presents an integrated navigation method based on inertial and geomagnetic information fusion. This method constructs the state and the measurement equation of inertial combination and MEMS triaxial magnetometer, also uses Kalman filter algorithm based on feedback calibration. The navigation accuracy deviations are analyzed by inertial navigation in high, medium and low precision, together with the MEMS triaxial magnetometer under different accuracy of measurement. The result shows that inertial and geomagnetic information fusion navigation will decrease the accuracy requirements for inertial devices, leading to reducing the cost of the aircraft in the economic and quality and the need for installation space.
KEYWORDS: Magnetism, Sensors, Information fusion, Microelectromechanical systems, Gyroscopes, Magnetic sensors, Filtering (signal processing), Signal processing, Error analysis, Digital filtering
A decision-making method of navigation for the small spacecraft is proposed. Attitude information is obtained by microelectromechanical gyroscope and geomagnetism sensor. Kalman filter and other information fusion techniques are used to improve the navigation accuracy. The long-term on-orbit navigation control of small aircraft is realized, reducing the cost of on-orbit navigation.
Based on optical scattering theory of Aden–Kerker method, the extinction efficiencies of submicron hollow particles with 5 kinds of materials, such as graphite(C), brass powder (Cu), cupric oxide (CuO), cuprous oxide(Cu2O) and soot are given in this paper. Some influences of different materials, inner radius (x), outer radius (y), shell thickness (z) and x-z ratio(x/z) on the extinction efficiencies are studied respectively. Owing to lack of literature data, the optical constants of C, Cu, CuO, and Cu2O are firstly obtained by measuring infrared spectral transmittance of material piece and retrieving the equivalent optical constants combined with electromagnetic scattering theory and K-K relation. The results show that particle C, Cu, Cu2O and Soot have a good performance in stability of extinction efficiency distribution within 3-5μm; the extinction efficiencies of C, Cu, Soot decrease gradually with the shortening of the wavelength within 3-5μm; the extinction efficiency of all kinds of particles increase along with outer radius y increased when shell thickness z is fixed.
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