the recent dedicated satellite gravimetry missions have provided huge amount of high quality gravity data with global coverage. from computational point of view, estimation of the unknown gravity field parameters is a highly demanding task due to the sheer number of observations and the unknown coefficients. different computational schemes have been proposed to tackle the problem. since the ear...

This work describes global gravity field modeling from observations of the CHAMP and the GOCE satellite mission. In the case of CHAMP the so-called Energy Balance Approach is applied to measurements of GPS high-low tracking of the low orbiting CHAMP spacecraft. In the case of GOCE gravity gradiometry is the main observable. The experience gained processing real data of the CHAMP satellite missi...

this paper develops new results on the use of model predictive control to regulate the attitude of a ground station antenna. two degree of freedom az-el pedestal is considered as ground station antenna. permanent magnet synchronous motors are taken into consideration as the best choice for satisfaction of control objectives as actuators. the design is based on a two cascade controller consist o...

gravity recovery and climate experiment (grace) satellite gravimetry mission launched in march 2002 based on its twin gravimetric satellites makes application of both high-low (hl) and law-low (ll) gravimetric techniques possible. the ll is based on satellite-to-satellite tracking (sst) via the one way two frequencies k-band-ranging between the two grace satellites. as a result of combination o...

satellite thermal control ensures safe operating temperature ranges for satellite components throughout the mission life. effects of altitude, spin, and position of satellite radiator(s) on the thermal control of a small low earth orbit (leo) satellite have been studied. results show that change in satellite altitude, in the range considered here, does not produce critical thermal conditions. h...

one of the main problems in wind energy conversion system (wecs) is how to achieve maxim­u­m output power in different wind speeds. maximum methods for maximum power point tracking in wind energy conversion syst­e­ms require the knowledge of system characteristics and mechanic sensors. so, using these methods practically will follow with high price and an abundant difficulties. in this paper, n...