Accession Number:

ADA048287

Title:

Design for High Accuracy Critical-Angle Sun Transit Sensor

Descriptive Note:

Technical note

Corporate Author:

MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB

Personal Author(s):

• Trudeau, Norman R.
• Howland, Bradford

Report Date:

1977-10-20

Pagination or Media Count:

51.0

Abstract:

A sun transit sensor is used to detect the suns passing a meridianal coordinate plane of the satellite. Accuracy of operation of earlier sensors is limited by curvature of the fan beams associated with the critical angle prism. A new, two-element critical angle prism assembly was described having the following properties a curvature of the fan beam can be cancelled, or balanced against higher order terms, b reflection occurs at the interface between the glasses, c achromatism is possible. A sensor utilizing two such prism assemblies operating in push-pull exhibits a planar fan beam having accuracy of or - sun latitude range of or - 30 deg equatorial orbit requirement, or or - 5 arc seconds for sun latitudes of 5 deg ecliptic orbit requirement. Equations governing the design, the choice of radiation resistant glasses, fabrication and testing will be discussed.

Descriptors:

• *PRISMS(OPTICS)
• COMPUTER AIDED DESIGN
• ACCURACY
• MEASURING INSTRUMENTS
• OPTICAL EQUIPMENT COMPONENTS
• OPTICAL GLASS
• SYNCHRONOUS SATELLITES
• SUN
• SATELLITE TRACKING SYSTEMS
• EQUATORIAL ORBITS
• ANGLES
• SATELLITE ATTITUDE

Subject Categories:

• Optics
• Spacecraft Trajectories and Reentry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE