Modelling of free space optical (FSO) communications and networking with low earth orbit (LEO) satellites

2021 ◽  
Author(s):  
William S. Rabinovich ◽  
Jeffrey W. Weston ◽  
Joseph P. Macker
Keyword(s):  
Free Space ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Free Space Optical ◽  
Leo Satellites

scholarly journals Detecting Targets above the Earth’s Surface Using GNSS-R Delay Doppler Maps: Results from TDS-1

2019 ◽  
Vol 11 (19) ◽  
pp. 2327 ◽  
Author(s):  
Changjiang Hu ◽  
Craig Benson ◽  
Hyuk Park ◽  
Adriano Camps ◽  
Li Qiao ◽  
...  
Keyword(s):  
Specular Reflection ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Navigation Satellite ◽  
Reflection Point ◽  
Leo Satellites ◽  
Gnss Reflectometry ◽  
Global Navigation Satellite ◽  
Remotely Sense

Global Navigation Satellite System (GNSS) reflected signals can be used to remotely sense the Earth’s surface, known as GNSS reflectometry (GNSS-R). The GNSS-R technique has been applied to numerous areas, such as the retrieval of wind speed, and the detection of Earth surface objects. This work proposes a new application of GNSS-R, namely to detect objects above the Earth’s surface, such as low Earth orbit (LEO) satellites. To discuss its feasibility, 14 delay Doppler maps (DDMs) are first presented which contain unusually bright reflected signals as delays shorter than the specular reflection point over the Earth’s surface. Then, seven possible causes of these anomalies are analysed, reaching the conclusion that the anomalies are likely due to the signals being reflected from objects above the Earth’s surface. Next, the positions of the objects are calculated using the delay and Doppler information, and an appropriate geometry assumption. After that, suspect satellite objects are searched in the satellite database from Union of Concerned Scientists (UCS). Finally, three objects have been found to match the delay and Doppler conditions. In the absence of other reasons for these anomalies, GNSS-R could potentially be used to detect some objects above the Earth’s surface.

Analysis of free space optical (FSO) communications and networking using adaptive waveforms for LEO satellites

2020 ◽  
Author(s):  
William S. Rabinovich ◽  
Rita Mahon ◽  
Mike S. Ferraro ◽  
Joseph P. Macker ◽  
Jeffrey Weston
Keyword(s):  
Free Space ◽  
Free Space Optical ◽  
Leo Satellites

Modular Ka-band switch matrices using two RF MEMS technologies

2013 ◽  
Vol 5 (3) ◽  
pp. 351-359
Author(s):  
Sascha A. Figur ◽  
Erika Meniconi ◽  
Ulrich Prechtel ◽  
Volker Ziegler ◽  
Roberto Sorrentino ◽  
...  
Keyword(s):  
Rf Mems ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Mems Switches ◽  
Data Links ◽  
Rf Mems Switches ◽  
Leo Satellites ◽  
Switching Matrix ◽  
Operational Frequency ◽  
Insertion Losses

This paper presents the design and measurement of two different switch matrix modules based on Radio Frequency Microelectromechanical System (RF MEMS) switches. The operational frequency range is between 25.5 GHz and 26.5 GHz for data links between a Geostationary Earth Orbit (GEO) relay satellite and Low Earth Orbit (LEO) satellites. The switch matrix implements a key functionality for tracking the incident signals of the LEO satellites on the receive feed antenna array of the GEO satellite's reflector antenna. Two different technologies are used to build simplified switch matrix modules suitable for realizing the full functionality switching matrix. Rogers RT/Duroid 5880 with commercially available RF MEMS is used to build the first module, while EADS in house RF MEMS are integrated in Rogers Ultralam 3850 Liquid Crystal Polymer (LCP) for the second module. Maximum insertion losses of 8.5 dB and 10.2 dB have been measured for the Rogers RT/Duroid 5880 and the LCP module, respectively. Isolation is higher than 45 dB and a minimum return loss of 15 dB is shown. Finally, the measured losses in the LCP module are analyzed and suitable improvements are discussed.

SUPPORTING DISTRESS SIGNALS OVER LOW EARTH ORBIT MOBILE SATELLITE SYSTEMS FOR EMERGENCY INFORMATION ACQUISITION

2013 ◽  
Vol 09 (03n04) ◽  
pp. 1350018
Author(s):  
GAMAL A. HUSSEIN ◽  
MOSTAFA A. NOFAL ◽  
MOAWAD I. DESSOUKY ◽  
OSAMA ALY ORABY ◽  
WALEED AL-HANAFY ◽  
...  
Keyword(s):  
Information Acquisition ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Rescue Operation ◽  
Satellite Systems ◽  
Leo Satellites ◽  
Mobile Satellite ◽  
Voice Data ◽  
Leo Satellite ◽  
Service Priority

Low earth orbit (LEO) satellite systems allow a broad range of services to be provided using small, lightweight, cellular-like portable telephones. Exploiting LEO satellites to support distress signals for aircrafts, ships and international travelers is explored in the current paper. A multi-service priority-oriented algorithm is proposed for handling voice, data and emergency signals over LEO satellites. The emergency signal is privileged with service priority so that rescue operation can be carried out as soon as possible. The priority mechanism includes channel reservation as well as joining a queue if no free channel is available as long as the request is roaming in the handover area. In addition, a simplified but efficient approach is suggested for locating the object of an imminent danger situation. As LEO satellites are non-geostationary, the visible period of each spot-beam is small. Consequently, a teletraffic model, that accommodates the mobility of spot-beams as well as the resulting handover rate, is developed in order to gauge the performance of the proposed algorithm. Numerical results for access denying and service-dropping rates are presented for nominal system parameters.

scholarly journals The Impact of Innovation in the Satellite Industry on the Telecommunications Services Market

2020 ◽  
Vol 73 ◽  
Author(s):  
Krasimir Terziev ◽  
Dimitar Karastoyanov
Keyword(s):  
Low Earth Orbit ◽  
Earth Orbit ◽  
Orbit Satellite ◽  
Leo Satellites ◽  
Different Types ◽  
Telecommunications Services ◽  
Global Communications ◽  
The Impact

The article analyses the role of the satellites in global communications. Different types of orbits and different types of satellites are described. The commercial start of low and medium orbit satellites is considered. The integration of some Low Earth Orbit (LEO) projects with Teleports is commented. Some significant LEO/MEO (Medium Earth Orbit) projects are cited. The impact of the satellite industry and the Teleport systems on the technological ecosystem is discussed. LEO satellites for monitoring the earth's surface are presented. Keywords: LEO, Orbit, Satellite, Teleport.

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