Different thicknesses of smooth and uniform carbon coatings composed of disordered carbon and micro-crystallite graphite were prepared on KD-II silicon carbide (SiC) fibres by atmospheric pressure chemical vapour deposition. The effects of carbon coatings on the mechanical property and thermal stability of SiC fibres were investigated. Carbon coatings have both favourable and unfavourable influences on SiC fibres strength. The fibres with up to 0.3 µm carbon coatings showed higher strength than the uncoated fibres due to surface flaw healing effect of the thin coatings, in contrast, the 1 µm carbon-coated fibres showed lower strength than uncoated fibres owing to effect of soft nature of the thick coatings. Furthermore, the carbon coatings effectively improved the thermal stability of SiC fibres by suppressing thermal decomposition of SiC X O Y and SiC X O Y N Z phase.

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The satellite attitude determination approach based on the Extended Kalman Filter (EKF) has been widely used in many real applications. However, the accuracy of this method largely depends on the fitness of measurement model. We aim to analyse the influence of measurement errors to the accuracy of EKF based attitude determination approach in this paper. The measurement errors, which are divided into structural error and nonstructural error by their influences, are analysed in principle. In the setting of the combination of star sensors and gyros, according to the property of innovation, we employ the technique of correlation test to analyse the influences of different kinds of measurement errors. Experimental results demonstrate the effectiveness of our previous analysis.