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Proceedings Paper

Pointing, acquisition, and tracking considerations for mobile directional wireless communications systems
Author(s): John Rzasa; Mehmet Can Ertem; Christopher C. Davis
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Paper Abstract

High capacity directional wireless communications networks are an active research area because of their Gb/s or greater data rates over link lengths of many kilometers, providing fiber-like networks through the air. Their high data rates arise partly from their very high carrier frequencies (<60GHz for RF, and ~1550nm for free-space optical (FSO)) and partly because of their very narrow beamwidths. This second characteristic requires that transceivers be pointed precisely to their counterparts. In almost all cases this means that the transceiver aperture is mechanically pointed by a rotation stage, commonly known as a gimbal. How these platforms initially point at a target, acquire the signal, and then stay locked on the signal is known as pointing, acquisition, and tracking (PAT). Approaches for PAT in both RF and FSO have some similarities, but require overall divergent solutions, especially if the platforms are moving. This paper elaborates on the various considerations required for designing and implementing a successful PAT system for both directional RF and FSO systems. Approaches for GPS or beacon based pointing, types of acquisition scans, and the effects of platform vibration are analyzed. The acquisition time for a spiral scan of a given radius with an initial pointing error has been measured experimentally for a gimbal pointing system.

Paper Details

Date Published: 25 September 2013
PDF: 10 pages
Proc. SPIE 8874, Laser Communication and Propagation through the Atmosphere and Oceans II, 88740C (25 September 2013); doi: 10.1117/12.2026691
Show Author Affiliations
John Rzasa, Univ. of Maryland, College Park (United States)
Mehmet Can Ertem, Univ. Research Foundation (United States)
Christopher C. Davis, Univ. of Maryland, College Park (United States)

Published in SPIE Proceedings Vol. 8874:
Laser Communication and Propagation through the Atmosphere and Oceans II
Alexander M. J. van Eijk; Christopher C. Davis; Stephen M. Hammel, Editor(s)

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