For a better understanding and forecasting of the universe, the high resolution observations are needed. The largeaperture telescope is an integrated success with a combination of material, mechanics, optics and electronics. The telescope is a classic Cassegrain configuration with open structure, alt-azimuth mount, and retractable dome. The instrumentation has a rotating mass of approximately 52 tons and stands over 9 m tall. The 3-m aperture primary mirror is a honeycomb lightweighted mirror with fused silica material and active cooling. The paper will address preliminary design and development of the telescope mount structure, axes drive system, encoder mount and primary mirror system. The structure must have the best performance of stiffness and stability to demand an acceptable image quality. As the largest optical element of the telescope, primary mirror must be well controlled and protected both during operational and non-operational periods. An active cooling system of primary mirror is provided by a flushing subsystem at the front side and sucking subsystem on the central hole to keep the temperature of the facesheet close to that of ambient air. A two-layer mirror cover mounted on the elevation ring is proposed to protect the optical elements and inner beam tube from dust, dirt and debris. Furthermore, the latest plans for future upgrades will be also described.
We proposed an efficient method of direction of arrival (DOA) estimation for coherent signal based on sparse signal reconstruction. For the inter-atom interference of redundant dictionary affecting the feasibility of sparse signal reconstruction, in this paper, our method for the DOA estimation of coherent signal is based on regularized orthogonal matching pursuit (ROMP) algorithm by designing adaptive sensing dictionary to mitigate the inter-atom interference (AMIAI). Simulated results demonstrate effectiveness of the method by plotting spatial spectrum, by comparing the rootmean-square error (RMSE) of some methods and Cramér-Rao Lower Bound (CRLB) and by comparing the running time of some methods. Our approach makes effort to improve the estimation performance of algorithm and has overload capability.