Advanced Celestial Navigation Systems
Dr. J.P. Laine Division Leader – Positioning, Navigation and Timing DRAPER
Copyright © 2018 by The Charles Stark Draper Laboratory, Inc all rights reserved The Celestial Advantage
2 Celestial Navigation
• Mariners have used various celestial navigation techniques since ancient times – Sun, Polaris, the Sextant
• Sextant sightings – In order to determine position with a sextant, one needs 2 stars, local vertical, and a clock. – Position accuracy reference values: • 1 arcmin ~ 1 nautical mile • 1 arcsec ~ 30 meters
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Copyright © 2018 by The Charles Stark Draper Laboratory, Inc all rights reserved Automated Sextant – Astro-Inertial Navigation System
• On a dynamic platform, the biggest challenge is determining vertical → Requires an IMU Star Tracker • Mid 20th century saw automated astro- navigation systems in aircraft use (e.g. IMU SR-71 ANS)
1 arcsecond angle error results in a 30-meter position error
4 Copyright © 2018 by The Charles Stark Draper Laboratory, Inc all rights reserved Advanced Algorithm Development
STELLAR HORIZON ATMOSPHERIC REFRACTION • No local vertical required • Accuracy depends on knowledge of atmospheric density profile • Developed and published by DRAPER
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Copyright © 2018 by The Charles Stark Draper Laboratory, Inc all rights reserved Advanced Hardware Development
Shorter Optics Thin Optics
DRAPER Goal: Conformal Optical Sensor, Conformal with No Focal Length
Optical Flat Optic Sensors
Image Readout
Conventional Imaging Optic Focal Length
Image Readout at Focal Plane
DRAPER Goal: Conformal Optical Imaging Sensors
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Copyright © 2018 by The Charles Stark Draper Laboratory, Inc all rights reserved Summary
• Long history of Celestial Navigation
• Robust techniques
• Automated sextants integrated into astro-inertial navigation systems
• Advanced technologies developed in past decades
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