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Advanced Celestial 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 , , the

• Sextant sightings – In order to determine position with a sextant, one needs 2 , local vertical, and a . – 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 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 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 integrated into astro-inertial navigation systems

• Advanced technologies developed in past decades

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