Optimization of spherically arranged lens arrays based on class II and III geodesic polyhedra.

Spherical arrangement is a common way to pack lens arrays. Due to the restriction of original structures, the previous optimization methods based on icosahedral subdivision are only applicable to a few types of lens arrays adopting different numbers of sub-lenses. In order to design more types of lens arrays, an optimization packing method is proposed with the vertices of class II and class III geodesic polyhedra as the arrangement positions of sub-lenses.

Surface figure compensation of the primary mirror in a Ritchey-Chrétien space telescope by spring preloads.

To reduce the surface figure error induced by mechanical strains during the integration process of a high-precision mirror, a cost-efficient compensation method by spring preloads is proposed. The study is based on the primary mirror of a Ritchey-Chrétien space telescope with a focal length of 1200 mm. First, the surface figure degradation of the mirror during the assembly process is expressed and analyzed.

Generation of temporal fading envelope sequences for the FSOC channel based on atmospheric turbulence optical parameters.

The temporal characteristics of the free space optical communication (FSOC) turbulence fading channel are essential for analyzing the bit error rate (BER) performances and compiling the rationale of adaptive signal processing algorithms. However, the investigation is still limited since the majority of temporal sequence generation fails to combine the autocorrelation function (ACF) of the FSOC system parameters, and using the simplified formula results in the loss of detailed information for turbulence disturbances. In this paper, considering the ACF of engineering measurable atmospheric parameters, we propose a continuous-time FSOC channel fading sequence generation model that obeys the Gamma-Gamma (G-G) probability density function (PDF).