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Proceedings Paper

Precision attitude and position determination for the Advanced Land Observing Satellite (ALOS)
Author(s): Takanori Iwata
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Paper Abstract

The Advanced Land Observing Satellite (ALOS) is required to achieve stringent attitude determination accuracy (3.0×10-4deg on-board and 1.4×10-4deg ground-based), position determination accuracy (1m ground-based), and attitude stability (3.9 × 10-4deg/5sec) in order to provide precise geometric accuracy for high-resolution images without ground control points. It is designed to yield the geolocation determination accuracy of 6m from attitude and position estimates and that of 3m with an additional high-bandwidth measurement. Presented in this paper are ALOS's platform and ground systems technologies developed for achieving the attitude determination accuracy and the position determination accuracy. They include a precision star tracker, optimal attitude estimation algorithms (real-time and off-line), an alignment change reduction, a jitter sensor, a precision GPS receiver, and a ground-based position estimation algorithm. The star tracker provides the best star position accuracy (random error: 9.0arcsec, and bias error: 0.74arcsec). The on-board attitude determination algorithm estimates attitude quaternion by applying an extended Kalman filter. The off-line attitude estimation introduced an extended-Kalman-filter-based smoother. To minimize the alignment change, the sensors are placed on the optical bench subject to precise temperature control. The jitter sensor provides precise angular information (0.010arcsec) from 2Hz to 500Hz and extends the attitude determination bandwidth. The dual-frequency GPS receiver capable of measuring pseudoranges and carrier phases allows the ground-based position determination with sub-meter accuracy.

Paper Details

Date Published: 11 January 2005
PDF: 17 pages
Proc. SPIE 5659, Enabling Sensor and Platform Technologies for Spaceborne Remote Sensing, (11 January 2005); doi: 10.1117/12.579051
Show Author Affiliations
Takanori Iwata, Japan Aerospace Exploration Agency (Japan)

Published in SPIE Proceedings Vol. 5659:
Enabling Sensor and Platform Technologies for Spaceborne Remote Sensing
George J. Komar; Jinxue Wang; Toshiyoshi Kimura, Editor(s)

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