Asymmetrical Broadband GEO/LEO Satellite Communications System

2002 ◽  
Author(s):  
James LaPrade
Keyword(s):  
Satellite Communications ◽  
Leo Satellite ◽  
Communications System

Propagation Delay Characteristics Analysis in LEO Satellite Multi-Beam Antenna Coverage

2013 ◽  
Vol 791-793 ◽  
pp. 1931-1935
Author(s):  
Ming Ma ◽  
Xi Luan ◽  
Bin Li ◽  
Jian Jun Wu
Keyword(s):  
Satellite Communications ◽  
Propagation Delay ◽  
Satellite System ◽  
Calculation Model ◽  
Propagation Delays ◽  
Characteristics Analysis ◽  
Leo Satellite ◽  
Communications System ◽  
Calculated Analysis

In this paper a calculation model of propagation delays of satellite beams is introduced for LEO multi-beam satellite communications system. Based on actual parameters and beam coverage patterns of the Iridium and Globalstar system, the maximum propagation delay differentials in several typical beams from the center to the edge of the satellites coverage are calculated. Analysis of these results can provide reference for analyzing the feasibility of LEO multi-beam satellite system compatible with uplink synchronization in LTE.

scholarly journals Wave measurements on sea ice: developments in instrumentation

2006 ◽  
Vol 44 ◽  
pp. 108-112 ◽  
Author(s):  
M.J. Doble ◽  
D.J.L. Mercer ◽  
D.T. Meldrum ◽  
O.C. Peppe
Keyword(s):  
Satellite Communications ◽  
Weddell Sea ◽  
Data Recovery ◽  
The Arctic ◽  
Polar Regions ◽  
Constant Attention ◽  
Wave Measurements ◽  
Wire Strain ◽  
Propagation Of Waves ◽  
Communications System

AbstractTraditional methods of measuring the propagation of waves originating from ocean swell and other sources have relied on wire strain gauges, accelerometers or tiltmeters. All methods required constant attention to keep in range, while data recovery has demanded that the instrument site be revisited. In this paper, we describe the use of ultra-sensitive tiltmeters and novel re-zeroing techniques to autonomously gather wave data from both polar regions. A key feature of our deployments has been the use of the Iridium satellite communications system as a way of ensuring continuous data recovery and remote control of the instrumentation. Currently four instruments have been successfully reporting from the Arctic Ocean for over 18 months, with two further units deployed in 2005, one in the Weddell Sea, Antarctica, and one additional unit in the Arctic.

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