On-board error correction improves IR earth sensor accuracy

Alex, T. K. ; Kasturirangan, K. ; Shrivastava, S. K. (1989) On-board error correction improves IR earth sensor accuracy 40th Congress of the Astronautical Federation, Paris, France . p. 7.

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Abstract

Infra-red earth sensors are used in satellites for attitude sensing. Their accuracy is limited by systematic and random errors. The sources of errors in a scanning infra-red earth sensor are analyzed in this paper. The systematic errors arising from seasonal variation of infra-red radiation, oblate shape of the earth, ambient temperature of sensor, changes in scan/spin rates have been analyzed. Simple relations are derived using least square curve fitting for on-board correction of these errors. Random errors arising out of noise from detector and amplifiers, instability of alignment and localized radiance anomalies are analyzed and possible correction methods are suggested. Sun and Moon interference on earth sensor performance has seriously affected a number of missions. The on-board processor detects Sun/Moon interference and corrects the errors on-board. It is possible to obtain eight times improvement in sensing accuracy, which will be comparable with ground based post facto attitude refinement.

Item Type:Article
Source:Copyright of this article belongs to 40th Congress of the Astronautical Federation, Paris, France.
ID Code:88345
Deposited On:28 Mar 2012 09:50
Last Modified:28 Mar 2012 09:50

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