Building Automatic Antenna Tracking system for Low Earth Orbit(LEO) satellite communications

Author(s):  
Nimit Hongyim ◽  
Somsak Mitatha
2017 ◽  
Vol 7 (6) ◽  
pp. 2273-2276
Author(s):  
R. Narimani ◽  
L. Farhoudi

The objective of this study is the design and implementation of a Quadrifilar Helix Antenna (QHA) for telemetry, tracking and control of a Low Earth Orbit (LEO) satellite. Because of its cardioid-shaped circularly polarized beam, QHA can satisfy requirements of satellite communications completely. In this paper, a variation of QHA referred to as “self-phased QHA” with a single feeding circuit, has been proposed to reduce implementation complexity. The designed antenna has been analyzed and the experimental results show that the radiation pattern provides good wide-beam in the desired frequency while the antenna’s bandwidth is around 200MHz when VSWR is less than 2.


2014 ◽  
Vol 32 (10) ◽  
pp. 1207-1216 ◽  
Author(s):  
P. Janhunen

Abstract. Plasma brake is a thin, negatively biased tether that has been proposed as an efficient concept for deorbiting satellites and debris objects from low Earth orbit. We simulate the interaction with the ionospheric plasma ram flow with the plasma-brake tether by a high-performance electrostatic particle in cell code to evaluate the thrust. The tether is assumed to be perpendicular to the flow. We perform runs for different tether voltage, magnetic-field orientation and plasma-ion mass. We show that a simple analytical thrust formula reproduces most of the simulation results well. The interaction with the tether and the plasma flow is laminar (i.e. smooth and not turbulent) when the magnetic field is perpendicular to the tether and the flow. If the magnetic field is parallel to the tether, the behaviour is unstable and thrust is reduced by a modest factor. The case in which the magnetic field is aligned with the flow can also be unstable, but does not result in notable thrust reduction. We also correct an error in an earlier reference. According to the simulations, the predicted thrust of the plasma brake is large enough to make the method promising for low-Earth-orbit (LEO) satellite deorbiting. As a numerical example, we estimate that a 5 km long plasma-brake tether weighing 0.055 kg could produce 0.43 mN breaking force, which is enough to reduce the orbital altitude of a 260 kg object mass by 100 km over 1 year.


2014 ◽  
Vol 912-914 ◽  
pp. 1069-1072
Author(s):  
Te Jen Su ◽  
Jui Chuan Cheng ◽  
Ming Yuan Huang ◽  
Xun Xain Zhan

This paper presents a smart-routing mechanism of a control system to track Low Earth Orbit (LEO) satellites. Satellite tracking mainly relies on the antenna pointing database generated by SGP4 orbit forecasting model and follow the point coordinates to command the rotation of the axes. Gears rotation gaps will affect the strength of the received signal; the Proportional Integral (PI) controller is used to adjust the error values caused by the drive shaft mechanism. Particle swarm optimization (PSO) algorithm has fewer parameter settings and the advantages of fast convergence, which is adopted for variable selection and optimization for the parameters kp and ki of PI controller. The resolver feedback mechanism of actual angle indicator is using as a basis for performance adjustment in the search process. The experimental results of a three axes tracking system demonstrate the reliability and better performance of the proposed PSO-PI satellite tracking system.


Author(s):  
Cheng-Ying Yang ◽  
Jenq-Foung JF Yao ◽  
Chin-En Yen ◽  
Min-Shiang Hwang

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