Contemporary land-survey micro-satellites have general mass up to 100 kg and are placed on the orbit altitudes from 600 up to 800 km. For such spacecraft some principle problems on attitude determination, in-flight calibration and alignment are considered and elaborated methods are presented for their solving. We present discrete algorithms for calibration and alignment of the low cost strap-do...

It is well known that Global Navigation Satellite Systems signals (which include for example the U.S. GPS and its modernization, the Russian GLONASS, the future European Galileo, the Chinese COMPASS), commonly processed for navigation purposes, can also be used to characterize media where they propagate in. In the last decade, GNSS atmospheric and Earth’s surface remote sensing become more and ...

We i n v estigate, in the Shannon model, the security of constructions corresponding to double and two-key triple DES. That is, we consider F k1 F k2 and F k1 F ,1 k2 F k1 with the component functions being ideal ciphers. This models the resistance of these constructions to generic" attacks like meet in the middle attacks. We obtain the rst proof that composition actually increases the security...

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