Applicability of the langley method for non-geostationary in-orbit satellite effective isotropic radiated power estimation

The Effective Isotropic Radiated Power (EIRP) is a crucial parameter characterizing the transmitting antennas of a radiofrequency satellite link. During the satellite commissioning phase, the requirements compliance of communication subsystems is tested. One of the required tests concerns the EIRP of the satellite transmitting antenna. Ground-based power measurements of the satellite-emitted signal are collected to measure EIRP, provided that an estimate of the atmospheric losses is available from independent ancillary measurements or model data. This paper demonstrates the applicability of the so-called Langley method to infer EIRP and atmospheric attenuation simultaneously from ground-based power measurements, with no need for ancillary measurements. It is shown that the proposed method gives results similar to more traditional methods, without prior information on atmospheric attenuation. Thus, the proposed method can be applied to monitor EIRP throughout the satellite life-time from ground-based power measurements alone

Numerical investigation about the impact of struts on the European Space Agency Deep Space Antennas efficiency and sidelobes

Large reflector antennas require struts to mechanically support feeds or sub-reflectors. In many cases, these affect the antenna performance. This paper proposes a comparison between the European Space Agency Deep Space Antennas (DSAs) 3 and 4, in terms of impact of struts on antenna efficiency and sidelobes. The numerical simulations, carried out on the entire antenna model using Physical Optics, indicates that the struts of the new DSA4 can provide a reduced impact due to the different design

Impact of strut diameter on the European Space Agency Deep Space Antennas efficiency and sidelobes

Large reflector antennas require the presence of struts to support both feeds and sub-reflectors. Such structures affect the antenna behavior. The present paper proposes an investigation between struts of different radius, considering the structure of the European Space Agency Deep Space Antenna 3 (DSA3), in terms of side-lobes and efficiency. The numerical simulations, which employed Physical Optics, are compared with those related to the DSA4, in order to assess the impact of both the smaller radius and of the different shape of the struts on the antenna performances

On De-Pointing Effects Caused by Snow Accumulation on Radomes for Ground Stations Working at K-Band: An analysis of the SNOWBEAR project

Ground stations working at high frequencies, such as the K-band, installed at polar latitudes and protected by radomes, are increasingly used to support modern satellites. The effect that snow accumulation may have on the radome is consequently important, as at these frequencies it may jeopardize the satellite link. This article analyses an operative case, referred to as SNOWBEAR (Svalbard grouND StatiOn for Wide Band Earth observation dAta Reception), where a 6.4-m antenna has been installed at Svalbard, Norway, to track an Earth observation (EO) satellite, NOAA-20, for a period of two years. We demonstrate, using experimental data and numerical models, that a chief effect can be described in terms of de-pointing of the main beam, with a particular focus on the difference of de-pointing between the sum and delta modes, and that a real-time, effective, solution is not yet available