T-45C TS, ADV & IUT ENG-24
GINA Operating Characteristics
3.
Laser beam cavities are orthogonally [at right
angles] aligned to X, Y, and Z axes
4.
Laser beam optical cavities are drilled into special
glass
a.
Low-expansion ceramic glass: Zerodur
b.
Bore holes are gas filled (helium and neon
mixture)
c.
Bore holes contain the helium-neon plasma
discharge
d.
Plasma is a gas: electrically neutral, composed
of ions, electrons, and neutral particles
5.
Optical cavity mirrors – four (4)
a.
Two (2) flat mirrors; one for each 120 degree
turn
b.
Two (2) curved mirrors that are automatically
adjusted using piezoelectric transducers to
keep the laser beam lengths constant
NOTE: Laser cavity length varies mostly due to
temperature changes.
6.
a.
Two in each optical cavity
b.
Measure laser beam Doppler shift patterns
resulting from apparent earth-rotation
precession and transport precession over
earth’s surface
NOTE: Apparent precession is mathematically
cancelled out.
Original (9-98)
Page 24-12
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