Share Email Print

Proceedings Paper

SILEX acquisition and tracking sensors
Author(s): Robert A. Cockshott; David J. Purll
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

This paper describes the Acquisition Sensor Detection Unit (ASDU) and the Tracking Sensor Detection Unit (TSDU) developed by Sira Ltd to be flown in the European Space Agency's SILEX (Semi-conductor Inter satellite Link Experiment) terminals. These units were designed, manufactured and qualified by Sira under contract to Matra Marconi Space. Stringent vibration, thermal stability and video waveform noise and timing specifications were critical elements in the design. The ASDU consists of an optical head containing a 385 X 288 CCD and video buffer, and separate electronics box containing clock decoding electronics, CCD clock drivers and video amplifiers. The ASDU operates at a frame rate of 33 or 135 Hz and its noise performance allows the brightest pixel to be detected with an accuracy of +/- 0.5 pixel for input powers in the range 9 - 55 pW (33 Hz) or 16 - 240 pW (135 Hz) during acquisition. Using the ASDU signal, the SILEX pointing, acquisition and tracking system controls the pointing mirrors to centralize the beam, at which point it falls within the smaller TSDU field of view. The TSDU comprises a single 480 g unit containing a 43 mm focal length lens, a 14 X 14 CCD, and clock receiver and video amplifier electronics. During tracking the central 4 CCD pixels are used as a quadrant detector, and the TSDU has demonstrated a noise equivalent angle of 2.7 (mu) rad (1 (sigma) half cone, 180 pW optical input power) at a frame rate of 8 kHz.

Paper Details

Date Published: 20 April 1995
PDF: 9 pages
Proc. SPIE 2381, Free-Space Laser Communication Technologies VII, (20 April 1995); doi: 10.1117/12.207404
Show Author Affiliations
Robert A. Cockshott, Sira Ltd. (United Kingdom)
David J. Purll, Sira Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 2381:
Free-Space Laser Communication Technologies VII
G. Stephen Mecherle, Editor(s)

© SPIE. Terms of Use
Back to Top