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Galileo avionica precision star tracker

HYPER Industrial Feasibility Study Final Presentation Precision Star Tracker Activity WP ESTEC Noordwijk The Netherlands -th March CAgenda Introduction PST Requirements PST CCD Characteristics PST System Trade-o ? PST Baseline Con ?guration PST Optics PST internal ba e PST Accuracy Guide Star Catalogue Conclusions -th March ESTEC Noordwijk The Netherlands CIntroduction q PST purpose m To allow the measurement of the Lense-Thirring e ?ect ?? This measurement is performed as relative measurement between the Precision Star Tracker PST giving angles between a guide star ?xed in inertial space and an atomic gyroscope direction which has an extremely high short time sensitivity for rotation rates angular rates ?? The PST is directed to far-distant guide stars which are not a ?ected by the Lense- Thirring e ?ect They represent a reference for the measurement and for the motions of the satellite and its control ?? The second measurement is performed with an Atomic Sagnac Unit ASU which measures the rotations of freely falling atoms relative to a series of laser beams whose orientation is rigidly linked to the PST boresight -th March ESTEC Noordwijk The Netherlands CIntroduction q Today GA has the capability to provide Star Sensors for a wide variety of mission requirements and applications ranging from high accuracy pointing of scienti ?c instruments and platform to medium FOV sensors with AAD capability q The required accuracy of the HYPER PST is about times more severe than most accurate GA star trackers ISO XMM q This makes this study very challenging -th March ESTEC Noordwijk The Netherlands CPST Requirements q The PST requirements level from HYP- - are the following Req Requirement Value s R -PST- PST internal errors in the frequency - rad range between - Hz and Hz - arcsec R -PST- External measurement errors star - rad aberration etc in the frequency - arcsec range between - Hz and Hz R -PST- PST internal errors in the frequency - rad range below - Hz - arcsec R -PST- External measurement errors star - rad aberration etc in the frequency - arcsec range below - Hz R -PST- Timing Jitter ms -th March ESTEC Noordwijk The Netherlands CPST Requirements q Level from HYP- - m R -PST- R -PST- - Optical Distortion Residual Error R -PST- - Focal Length Variation with Temperature R -PST- - Focal Length Variation with Star Colour R -PST- - R -PST- - Photo Response Non-Uniformity E ?ect on Star Signal and Straylight Dark Current Non-Uniformity R -PST- - Centroiding Algorithm Error R -PST- - Arithmetic Round-O ? R -PST- - Noise Equivalent Angle - rad - arcsec - rad - arcsec - rad - arcsec - rad - arcsec - rad - arcsec - rad - arcsec - rad - arcsec - rad - arcsec -th March ESTEC Noordwijk The Netherlands CPST Requirements q Level from HYP- - m R -PST- R -PST- - Relativistic Aberration - rad - arcsec m R -PST- ?? No PST internal low frequency errors have been identi