Abstract
The state of the art attitude determination instrument for
spacecraft applications is a stellar compass (star tracker). It
can determine the attitude of a spacecraft relatively to the stars
with an accuracy better than 1 arcsecond (4.8 microradian). This
is achieved utilizing a CCD camera and a powerful microcomputer.
The microcomputer analyses the CCD images using an onboard
software star catalogue. The objective of the danish Oersted
microsatellite is to measure the magnetic field of the Earth. The
field is measured with a very accurate vector magnetometer. In
order to utilize the accurate vector measurements it is necessary
to relate the measurement to some fixed coordinate system. The
only instrument that is capable of doing so with the required
accuracy is a stellar compass. Hence the Oersted microsatellite is
equipped with a stellar compass, which will be discussed in this
paper. The design of the stellar compass is novel compared to
conventional star trackers, because it can make the initial
attitude acquisition autonomously (lost in space). This is
achieved by pattern recognition of star constellations in the CCD
image and a preflight compiled version of the star catalogue. The
technique will be described and the performance analyzed. Also,
the stellar compass is more accurate than conventional star
trackers, because conventional star trackers typically tracks 3-10
star in a single frame, whereas the stellar compass tracks up to
200 stars, yielding more accurate attitude estimates due to
statistical means. The accuracy, the performance and the high sky
coverage of this new approach is also discussed.
Original language | English |
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Title of host publication | Space Sciencecraft Control and Tracking in the New Millenium |
Place of Publication | Denver |
Publisher | SPIE |
Publication date | 1996 |
Pages | 239-251 |
Publication status | Published - 1996 |
Event | Space Sciencecraft Control and Tracking in the New Millenium - Denver, United States Duration: 6 Aug 1996 → 8 Aug 1996 |
Conference
Conference | Space Sciencecraft Control and Tracking in the New Millenium |
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Country/Territory | United States |
City | Denver |
Period | 06/08/1996 → 08/08/1996 |