Modeling and Fabrication of a Reconfigurable RF Output Stage for Nanosatellite Communication Subsystems

Current small satellite platforms such as CubeSats require robust and versatile communication subsystems that allow the reconfiguration of the critical operating parameters such as carrier frequency, transmission power, bandwidth, or filter roll-off factor. A reconfigurable Analog Back-End for the space segment of a satellite communication subsystem is presented in this work. This prototype is implemented on a 9.5 cm2 6-layer PCB, and it operates from 0.070 to 6 GHz and complies with CubeSat and IPC-2221 standards. The processing, control, and synchronizing stages are carried out on a Software-Defined Radio approach executed on a baseband processor. Results showed that the signal power at the output of the proposed Analog Back-End is suitable for feeding the following antenna subsystem. Furthermore, the emitted radiation levels by the transmission lines do not generate electromagnetic interference.

Analysis of the Impact of Multipath on Galileo System Measurements

Multipath is one of the major source of errors in precise Global Navigation Satellite System positioning. With the emergence of new navigation systems, such as Galileo, upgraded signals are progressively being used and are expected to provide greater resistance to the effects of multipath compared to legacy Global Positioning System (GPS) signals. The high quality of Galileo observations along with recent development of the Galileo space segment can therefore offer significant advantages to Galileo users in terms of the accuracy and reliability of positioning. The aim of this paper is to verify this hypothesis. The multipath impact was determined both for code and phase measurements as well as for positioning results. The code multipath error was determined using the Code-Minus-Carrier combination. The influence of multipath on phase observations and positioning error was determined using measurements on a very short baseline. In addition, the multipath was classified into two different types: specular and diffuse, using wavelet transform. The results confirm that the Galileo code observations are more resistant to the multipath effect than GPS observations. Among all of the observations examined, the lowest values of code multipath errors were recorded for the Galileo E5 signal. However, no advantage of Galileo over GPS was observed for phase observations and for the analysis of positioning results.

Optimization of the parameters of advanced multi-beam satellite systems

Исследовано техническое обеспечение спутниковых многолучевых систем прямого направления и поставлена задача оптимизации параметров этих систем. На основе анализа параметров космического сегмента для абонентских лучей и структуры передающей части бортового ретранслятора предложены варианты частотно-поляризационного плана для улучшения энергетического потенциала спутниковой системы. Показаны способы увеличения зоны обслуживания луча исследуемых систем более чем в 2 раза. The technical support of satellite multi-beam systems of the forward direction is investigated and the problem of optimization of the parameters of these systems is set. Based on the analysis of the parameters of the space segment for subscriber beams and the structure of the transmitting part of the on-board repeater, variants of the frequency-polarization plan are proposed to improve the energy potential of the satellite system. Methods of increasing the service area of the beam of the systems under study by more than 2 times are shown.

Metop-C deployment and start of three-satellite operations

ABSTRACTMetop is the space segment of the EUMETSAT Polar System (EPS), which provides real-time data to several European meteorological services as well as to the National Oceanic and Atmospheric Administration (NOAA) and other international agencies. The third Metop satellite, Metop-C, was launched on 7 November 2018 and shall enter in operations in few months, once the on-going commissioning of the meteorological products is completed. Each Metop satellite was designed to operate at least five years. A sequential deployment of the satellites was foreseen to achieve the target mission duration of 15 years, replacing an old one at end of life with a newer one; thanks to the excellent performances of the launchers and of the platform itself, and to continuous improvements to the fuel management, it was possible to extend the operational life of each satellite by a factor of three, still maintaining enough fuel to perform safe de-orbiting operations (foreseen for Metop-A, launched in 2006, at the end of 2021). This provided the opportunity to develop in 2012 (after Metop-B launch) dual-satellite products, which now, with the arrival of Metop-C, can evolve to tri-satellite; several decisions, concerning the selection of launch date and time as well as commissioning and operational locations, had to be been taken to achieve the target configuration; the analyses leading to these decisions are discussed here.

A microwave active filter for nanosatellite’s receiver front-ends at s-bands

<p>In satellite technology, the communication between space segment and ground segment plays a vital role in the success of the mission. This paper is targeted at study, design and fabrication of a microwave active filter for the receiver front-ends using coupled line filter structure, which can be applied to the nanosatellite’s communication subsystem. The whole active filter module is a combination of a microstrip bandpass filter and a preceding two-stage wideband low noise amplifier using FET devices. The proposed module operates in the frequency range of 2 - 2.4 GHz, which can be divided to 10 frequency slots of about 40 MHz for each. These frequency slots will be used for the S-band multi-frequency receiving function of the ground station, as well as the nanosatellite. The simulated and measured results of this active filter configuration are presented.</p>