scholarly journals Bistatic Scattering due to Hydrometeors on Cochannel Intersystem Communication Links over a Subtropical Path

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
P. A. Owolawi ◽  
T. Wallingo
Keyword(s):  
Transmission Loss ◽  
Cell Model ◽  
Satellite System ◽  
Rain Attenuation ◽  
Small Time ◽  
Satellite Systems ◽  
Satellite Design ◽  
Interference Level ◽  
Communication Links ◽  
Downlink Signal

The performance of fixed satellite systems in the shared frequency band depends on the tolerance level of interference between them. Interference disturbs the functionality of the ground station and causes signal degradation. The knowledge of interference level must therefore be known for an optimal satellite design. In this work, we evaluate interference due to hydrometeors for a situation in which a satellite downlink signal is affected by the signal from a terrestrial microwave network operating at the same frequency as the satellite system in a subtropical station: Durban, South Africa. The evaluation of the transmission loss is based on the modified 3D bistatic radar equation and the exponential rain cell model for the scattering. The results of intersystem interference for different station separation over frequencies variation, terrestrial antenna gains, and exceedance probabilities are presented. The effect of the additional rain attenuation(Aw)on the satellite signals is also examined. The results point out to some remarkable attenuation differences between the effective transmission loss and the transmission loss statistics for small time unavailability at the frequencies considered in this work. This could be detrimental in link budget design if overlooked.

PROCEDURE OF CALCULATING THE REDUCED COSTS FOR DESIGNING A COMBINED LOW-ORBIT SATELLITE SYSTEM

2017 ◽  
Author(s):  
Vitaly Pochernyaev ◽  
◽  
Tetiana Kadatska ◽  
Keyword(s):  
Satellite System ◽  
Observation Data ◽  
Satellite Systems ◽  
Capital Costs ◽  
Ground Segment ◽  
Rocket Carrier ◽  
Approximate Cost ◽  
Main Component ◽  
The Cost ◽  
Space Segment

The article provides a method for calculating the costs when designing a promising embodiment of a low-bit satellite system. For Ukraine, the prospects for this option lies in the fact that their own means of achieving a large number of satellites in orbit are applied. At the same time, satellites are multifunctional and used to organize communication and broadcasting, the sounding of the atmosphere and the surface of the Earth, subsurface locations, cosmic observation, data collection from the Internet sensors. The space group consists of mini, macro-, nanosterans, which are delivered to the orbit of a domestic rocket carrier into orbit. The technical and economic efficiency of the satellite system lies not only in the above advantages, but also in its hierarchical construction - combination of the root satellite, ministerial repeater, macrovers. The article provides an analysis of other low-bit satellite systems. A feature of the study of the combined LEO is the fact that the proposed construction of the satellite system allows the use of technological distributed registries as one of the through digital technologies. In digital transformation of the economy, the technology of distributed registers plays the same role as Internet things, cloud computing, 5G and Big Data technologies. The method of calculating the presented costs is to calculate the cost of the development, production and operation of the system at the stage of its design. The costs of developing space and ground segments are included in the total capital costs. The costs of developing a space segment are highlighted on the cost of developing a root satellite, a minivan-repeater, microscope. The same approach is also laid for the cost of exploitation of the space segment. When calculating the costs of the ground segment as the main component of earth stations, antenna systems, radio transmission microwaves and radio receiving microwaves, information processing devices, terminal equipment are taken as the main components of earth stations. The approximate cost of serial production of root sieuine, mini satellite, retrograder, microsatellite is indicated. The estimated cost of one minute of access in the studied combined LEO and in the existing "close" to the appointment of a low-bit satellite system is given.

scholarly journals Dynamic Beam Hopping Time Slots Allocation Based on Genetic Algorithm of Satellite Communication under Time-Varying Rain Attenuation

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2909
Author(s):  
Chen Zhang ◽  
Jiangtao Yang ◽  
Yong Zhang ◽  
Ziwei Liu ◽  
Gengxin Zhang
Keyword(s):  
Genetic Algorithm ◽  
Resource Allocation ◽  
Satellite Communication ◽  
Rain Attenuation ◽  
Time Varying ◽  
Dynamic Allocation ◽  
Satellite Systems ◽  
Flexible Resource ◽  
Conventional Methods ◽  
High Level

Beam hopping technology is considered to provide a high level of flexible resource allocation to manage uneven traffic requests in multi-beam high throughput satellite systems. Conventional beam hopping resource allocation methods assume constant rainfall attenuation. Different from conventional methods, by employing genetic algorithm this paper studies dynamic beam hopping time slots allocation under the effect of time-varying rain attenuation. Firstly, a beam hopping system model as well as rain attenuation time series based on Dirac lognormal distribution are provided. On this basis, the dynamic allocation method by employing genetic algorithm is proposed to obtain both quantity and arrangement of time slots allocated for each beam. Simulation results show that, compared with conventional methods, the proposed algorithm can dynamically adjust time slots allocation to meet the non-uniform traffic requirements of each beam under the effect of time-varying rain attenuation and effectively improve system performance.

scholarly journals Analysis of the Effect of Different Combinations of Observation Satellites on the Resolving Accuracy of GNSS Observation Data

2020 ◽  
Vol 206 ◽  
pp. 03025
Author(s):  
Junze Wang ◽  
Maohua Yao ◽  
Wenting Zhou ◽  
Xiangping Chen
Keyword(s):  
Measurement Accuracy ◽  
Control Point ◽  
Satellite System ◽  
Base Stations ◽  
Observation Data ◽  
Control Points ◽  
Level Control ◽  
Satellite Systems ◽  
Beidou Navigation Satellite System ◽  
Stable Measurement

In this paper, 24 C-level control points under different terrain conditions were selected to be the testing points. The binary-satellite system (GPS+GLONASS) and the triple-satellite system with BeiDou Navigation Satellite System (BDS) (BDS+GPS+GLONASS) were adopted for static measurement; and the observation data from BeiDou Ground-based Augumentation System (GBAS) base stations in Guangxi were collected for solution. By comparing the residuals of GPS tri-dimensional baseline vectors and the internal accord accuracy of each control point under the binary and triple-satellite systems, the effect of data collected by different satellite systems under different terrain conditions on measurement accuracy was studied. According to the results, (1) the triple-satellite system with BDS showed more stable measurement accuracy; (2) in plane, the two systems were of equivalent measurement accuracy in mountainous and flat areas; in elevation, the triple-satellite system showed higher and more stable measurement accuracy.

scholarly journals Analysis of Time Diversity Gain for Satellite Communication Link based on Ku-Band Rain Attenuation Data Measured in Malaysia

2018 ◽  
Vol 8 (4) ◽  
pp. 2608
Author(s):  
Islam Md. Rafiqul ◽  
Ali Kadhim Lwas ◽  
Mohamed Hadi Habaebi ◽  
Md Moktarul Alam ◽  
Jalel Chebil ◽  
...  
Keyword(s):  
Satellite Communication ◽  
Satellite Communications ◽  
Earth Satellite ◽  
Rain Attenuation ◽  
Diversity Gain ◽  
Communication Link ◽  
Time Diversity ◽  
Communication Links ◽  
System Time ◽  
Diversity Technique

<p><span>This paper reports a study on mitigation of propagation impairments on Earth–space communication links. The study uses time diversity as a technique for mitigating rain propagation impairment in order to rectify rain fade. Rain attenuation time series along earth-to-satellite link were measured for two years period at 12.255 GHz in Malaysia. The time diversity technique was applied on measured rain fade to investigate the level of possible improvement in system. Time diversity gain from measured one-minute rain attenuation for two years period was estimated and significant improvement was observed with different delays of time. These findings will be utilized as a useful tool for link designers to apply time diversity as a rain fade mitigation technique in Earth-satellite communications systems.</span></p>

scholarly journals Code Single Point Positioning Using Nominal Gnss Constellations (Future Perception)

2007 ◽  
Vol 42 (3) ◽  
pp. 149-153
Author(s):  
A. Farah
Keyword(s):  
Single Point ◽  
Satellite System ◽  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Performance Improvements ◽  
Single Point Positioning ◽  
Global Navigation ◽  
Point Positioning ◽  
Global Navigation Satellite

Code Single Point Positioning Using Nominal Gnss Constellations (Future Perception) Global Navigation Satellite Systems (GNSS) have an endless number of applications in industry, science, military, transportation and recreation & sports. Two systems are currently in operation namely GPS (the USA Global Positioning System) and GLONASS (the Russian GLObal NAvigation Satellite System), and a third is planned, the European satellite navigation system GALILEO. The potential performance improvements achievable through combining these systems could be significant and expectations are high. The need is inevitable to explore the future of positioning from different nominal constellations. In this research paper, Bernese 5.0 software could be modified to simulate and process GNSS observations from three different constellations (GPS, Glonass and Galileo) using different combinations. This study presents results of code single point positioning for five stations using the three constellations and different combinations.

Simulation analysis and performance of a feasible GNSS system with multi-beam antennas deployment operating in Galileo frequency bands

2012 ◽  
Vol 4 (5) ◽  
pp. 537-543
Author(s):  
Constantinos T. Angelis
Keyword(s):  
Simulation Analysis ◽  
European Space Agency ◽  
Satellite System ◽  
Access Time ◽  
Maximum Efficiency ◽  
Satellite Systems ◽  
Space Agency ◽  
Simulation Results ◽  
And Performance ◽  
Global Navigation Satellite

New Global Navigation Satellite System (GNSS) systems under development, such as Galileo, are very promising for future global positioning-based applications. A vast research is undergoing a final stage of implementation in order to fulfill the primary purpose of European Space Agency for developing and then sustaining of 30 (27 + 3 spares) Galileo satellites in orbit. This article presents simulation results for a realistic deployment of multibeam antennas, with a new modified theoretical pattern, in GNSS Satellite Systems. The proposed multibeam antennas use 61-spot beams for maximum efficiency in terms of satellite coverage and accessing high quality of service. In order to prove the reliability and feasibility of this work, various simulations were conducted using the upcoming Galileo system as a platform taking into consideration real-world conditions. Gain analysis versus elevation, Bit Error Rate (BER) and access time simulation results show that the viability of the proposed multibeam antenna deployment is established.

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