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BLITSCenter of Mass Information:The figure below shows the optical layout of the BLITS retroreflector.
The total optical path length inside the glass sphere is:
where n1 = 1.7646(at +20°C and λ=532nm) is the refraction index of the inner flint glass ball having a radius of R1=53.52mm, and n2=1.4731(at +20°C and λ=532nm) is the refraction index of the outer crown glass layer having an external radius of R2=85.16mm. The geometrical path length of the laser light from the incidence point to the ball center is equal to the radius R2. Thus, the correction value is:
Thus to correct the measured one-way laser range to the center of mass of the satellite, 196.94 mm should be SUBTRACTED from that measured one-way range. The calculated correction value variation caused by the glass refraction indexes temperature dependence is less than 0.1 mm with in a temperature range of ± 35°C (relative to +20°C). |
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