Shkelzen Cakaj

LEO (Low Earth Orbit) environmental satellites provide continuous coverage of Earth, supplying meteorological and oceanic observation data which are important in aerospace and maritime. The missions of such satellites are mainly based on photo imagery. For photo imagery, it is also important that the area observed from the satellite is treated under the same lighting conditions. This can be achieved by keeping the orbital plane position constant relative to the Sun due to the Earth’s motion around the Sun, defined as orbital Sun synchronization. The line of nodes defines the orientation of the satellite’s orbital plane in space. Nodal regression is defined as the shift of the orbit’s line of nodes over time, as Earth revolves around the Sun. Nodal regression is caused by the Earth’s oblateness. Nodal regression is a very useful feature, especially used to synchronize low Earth circular orbits with the Sun. Nodal regression depends on orbital attitude and orbital inclination angle. This paper provides an inclination window calculation for different attitudes in order to maintain orbital Sun synchronization.

The project "MOST" (micro variability and oscillations of stars) is a Canadian micro satellite space telescope mission. The micro satellite carries a Rumak-Maksutov telescope with an aperture of 15 cm. The size of the satellite is 65 cmtimes65 cmtimes30 cm and the mass is about 65 kg. The goals of the mission are to analyze the inner structure of stars, set a lower limit to the age of the universe and to search for Exoplanets. The project MOST consists of a low Earth orbiting (LEO) satellite and three ground stations, one of them in Vienna. The Vienna ground station system was set up at the Institute for Astronomy of the University of Vienna in cooperation with the Institute of Communications and Radio-Frequency Engineering of the Vienna University of Technology. During the link budget calculations atmospheric attenuation had to be considered. The satellite link operates in 2 GHz band. In this band the ionospheric effects are negligible. This paper presents the methodology applied for rain attenuation calculations

Noise introduces a fundamental limit on the performance of any communication system. Satellite communication systems are particularly susceptible to noise because of their inherent low received power. During the link budget calculations, noises of the equipment and line loss have to be considered. An alternative, but equivalent way of expressing the noisiness of the equipment and line loss is through noise temperature. The noise temperature which represents noise of all components in satellite receiving system chain is called composite noise temperature. Thus, on this paper the methodology applied for composite noise temperature calculations for satellite links is presented. In order to illustrate these calculations, data of Vienna ground station within MOST project are applied. The project MOST (microvariability and oscillations of stars) is a Canadian micro satellite space telescope mission. The project MOST consists of a low earth orbiting (LEO) satellite and three ground stations, one of them in Vienna. The Vienna ground station system was set up at the Institute for Astronomy of the University of Vienna in cooperation with the Institute of Communications and Radio-Frequency Engineering of the Vienna University of Technology. The satellite link operates on 2 GHz band

The project "MOST" (Microvariability and Oscillations of Stars) is a Canadian micro satellite space telescope mission. The micro satellite carries a Rumak-Maksutov telescope with an aperture of 15 cm. The size of the satellite is 65 cm times 65 cm times 30 cm and the mass is about 65 kg. The goals of the mission are to analyze the inner structure of stars, set a lower limit to the age of the universe and to search for Exoplanets. The project MOST consists of a low Earth orbiting (LEO) Satellite and three ground stations, one of them in Vienna (W. Weiss and W. Keim, 2003). The Vienna ground station system was set up at the Institute for Astronomy of the University of Vienna in cooperation with the Institute of Communications and Radio-Frequency Engineering of the Vienna University of Technology. The ground satellite station in Vienna is installed in urban area with high penetration of GSM 1800 mobile systems. This paper presents the investigations related to the possibility of disturbances by the intermodulation factors generated by uplink signal and GSM 1800 mobile signals