The advancing state-of-the-art in second generation star trackers

Until recently, only first-generation charge coupled device (CCD) spacecraft star trackers have been available. These track a small number of bright stars and are dependent on external processing for acquisition, calculation of corrections and transformation from CCD referenced to inertial referenced coordinates. Now, powerful microprocessors (>10 million instructions per second (MIPS)) with a few Mbytes of memory have become available in space qualified grades and have enabled the next step in star tracker concepts: second-generation fully autonomous designs. These second-generation units are equipped with star catalogs covering the entire sky. Their microprocessors instantly perform acquisition by pattern recognition of the entire image, thus relating the output from the star tracker directly to the celestial sphere. Their output data can be used in the attitude control system of a spacecraft without intermediate data processing. This saves central processor load, memory capacity and integratation of thousands of line of source code. The use of a large number of stars in each data frame makes the attitude estimates more accurate and operation both smoother and more robust in comparison to first-generation star trackers.

[1]  John L. Joergensen,et al.  Astronomical performance of the engineering model Oersted Advanced Stellar Compass , 1996, Optics & Photonics.

[2]  M. Bollner,et al.  The ROSAT star tracker-flight experience , 1991 .

[3]  Carl Christian Liebe,et al.  Autonomous vision in space on an Advanced Stellar Compass platform , 1996, Optics & Photonics.

[4]  Philip C. Thomas,et al.  Star tracker for remote sensing satellites , 1994, Defense, Security, and Sensing.

[5]  E. Groth,et al.  A pattern-matching algorithm for two-dimensional coordinate lists. [for stellar positions] , 1986 .

[6]  Eric R. Fossum,et al.  Active pixel sensors for autonomous spacecraft applications , 1996, Optics & Photonics.

[7]  James R. Wertz,et al.  Spacecraft attitude determination and control , 1978 .

[8]  M. Barni,et al.  A new star-constellation matching algorithm for satellite attitude determination , 1993 .

[9]  Gunter Lange,et al.  The ROSAT Star Tracker , 1986, Astronomical Telescopes and Instrumentation.

[10]  Carl Christian Liebe,et al.  Operation and performance of a second generation, solid state, star tracker, the ASC , 1996 .

[11]  Bedabrata Pain,et al.  Active pixel sensor (APS) based star tracker , 1998, 1998 IEEE Aerospace Conference Proceedings (Cat. No.98TH8339).

[12]  Eric R. Fossum,et al.  Active pixel sensors: are CCDs dinosaurs? , 1993, Electronic Imaging.

[13]  Charles C. Kilgus,et al.  Autonomous star identification and spacecraft attitude determination with CCD star trackers , 1991 .

[14]  Roelof W. H. van Bezooijen.  True-sky demonstration of an autonomous star tracker , 1994 .

[15]  R. E. Williamson,et al.  Astros: A Sub-Arcsec CCD Star Tracker , 1984, Optics & Photonics.

[16]  P. M. Salomon,et al.  A microprocessor-controlled CCD star tracker , 1976 .

[17]  C.C. Liebe,et al.  Pattern recognition of star constellations for spacecraft applications , 1992, IEEE Aerospace and Electronic Systems Magazine.

[18]  Carl Christian Liebe,et al.  New generation of autonomous star trackers , 1997, Remote Sensing.

[19]  John L. Joergensen,et al.  Algorithms onboard the Oersted microsatellite stellar compass , 1996, Optics & Photonics.

[20]  A. F. Tolivar,et al.  Stochastic star identification , 1994 .