Given the RMS transmitter pointing error and the desired probability of bit error (PBE), it can be shown that an optimal transmitter antenna gain exists which minimizes the required transmitter power. Given the RMS local oscillator tracking error, an optimum receiver antenna gain can be found which optimizes the receiver performance. The impact of pointing and tracking errors on the design of direct-detection pulse-position modulation (PPM) and heterodyne noncoherent frequency-shift keying (NCFSK) systems is then analyzed in terms of constraints on the antenna size and the power penalty incurred. It is shown that in the limit of large spatial tracking errors, the advantage in receiver sensitivity for the heterodyne system is quickly offset by the smaller antenna gain and the higher power penalty due to tracking errors. In contrast, for systems with small spatial tracking errors, the heterodyne system is superior because of the higher receiver sensitivity. >

Impact of random pointing and tracking errors on the design of coherent and incoherent optical intersatellite communication links

Laser communication links in space are attractive alternatives to present day microwave links. Space communications as employed in satellite to satellite link is traditionally performed using microwaves. High capacity intersatellite communication crosslinks will permit more efficient and more reliable operation of future satellite systems. The mass, power consumption and size of optical transceiver module will be smaller than that of a microwave transceiver. On the other hand, inter-satellite communication is limited by “satellite vibration”. The ultimate disadvantages include misalignment in tracking, signal attenuation and high BER (bit error rate). In this paper, effect of satellite vibration on various parameters like pointing angle, received signal power and hence the BER of the system are studied and plotted using Matlab simulation.

A study on inter-satellite optical wireless communication and its performance analysis

Modeling and performance optimization of automated antenna alignment for telecommunication transceivers

Free Space Optics (FSO) is an optical communication technology that uses light propagating in free space to transmit data between two points. The technology is useful where the physical connections by the means of optical fibre cables are impractical to use due to high costs or other considerations. FSO has been proposed by using a laser. FSO is considered as one of the most popular choices for inter-satellite communication where the performance is limited by “satellite vibration”. FSO cannot achieve a stable and ‘healthy’ link due to such type of vibration. The ultimate disadvantages include misalignment in tracking, signal attenuation and high BER (bit error rate). Hence the satellite vibrations need to be compensated (or minimized). This paper introduces the feed-forward vibration compensation model by introducing PID controller. The simulation results indicate that the proposed method minimizes the vibration effects and hence reduces BER in satellite laser communication system [7]. General Terms Satellite, Vibration effect, PID controller, Feed-forward compensator.

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Ariq I. Aziz

Papers

Performance Improvement of the Tracking System of a Satellite Laser Communication