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Atmospheric clouds and fogs can weaken the intensity of the visible light by absorption, refraction, scattering and reflection, which greatly affect the detection effect of ground-based optical observation instruments. To solve this problem, near-earth space-based optical observation platform is a good choice which is more flexible and cheaper than satellite-based optical observation platform in space. This paper describes the whole design of the near-earth space optical observation payload cabin including electronics design and mechanical design. The payload capacity is 100Kg and supports 4x RS422, 4x CameraLink, 4x analog video and 4x LAN, it can provide energy supply, mode control, temperature control, data storage and data transmission services for the experiment loads. The payload cabin developed in this paper has participated in the actual experiment and reached to an altitude of 20 Km, and then safely landed after staying for 2 h in the stratosphere. The scientific load obtained real and reliable experimental data and the optical loads also obtained precious data and images during the experiment. The payload cabin developed in this experiment will take ultraviolet spectrograph, low-light level night vision device, planetary telescope and multi-band airglow imager to an altitude above 20Km for experiment in the near future. [ABSTRACT FROM AUTHOR]

Near earth space is a space which has important strategic significance and application value in military, scientific exploration and other industry fields, one of the most practical application is to make a reconnaissance platform that can work normally in the near earth space. In this paper, a two-dimensional photoelectric turntable for video surveillance in near-earth space is designed, which can observe the azimuth angle 360° and pitch angle from −110° to 10°, and the capacity of this photoelectric turntable is 7 kg in a space of ϕ300 mm. The optical imaging load in the photoelectric turntable can output high-definition video in real time and the original image is stored in the memory card simultaneous. What is more, the imaging effect can be adjusted by controlling the magnification and focal length by sending commands through serial communication ports. The two-dimensional photoelectric turntable designed in this paper is mounted on the payload cabin and raised to 32.5 km for surveillance imaging. The experimental results show that the two-dimensional photoelectric turntable can work normally in the harsh near space environment, and the optical imaging load can output and record fluent high-definition video. The photoelectric turntable designed in this paper will be equipped with other optical load and take part in some near space exploration tasks in the future and obtain corresponding result. [ABSTRACT FROM AUTHOR]

As the third pole of the earth, Qinghai Tibet Plateau breeds many unique species; their population size, living environment and migration process have been observed and studied by many researchers. However, these observations are mainly carried out in summer with UAVs when the temperature is high, while they are hard to work in winter since the harsh environment such as low temperature and strong wind. Here, we used a tethered balloon to observe and monitor Tibetan animals in the winter of Tibet Plateau with a long wave refrigeration infrared camera (resolution is 0.2 m@2 Km). The camera was installed on a two dimensional stable platform and was raised up to 150 m by the tethered balloon. The experiment results show that the camera on the tethered balloon can complete the observation in the harsh environment and obtain better images and videos including the mating process of two Tibetan antelopes. After this experiment, the acquired videos were used for further processing, such as motion detection and animal counting. This method can be used to observe other species occupying similar environment, such as Tibetan yak and Equus kiang. [ABSTRACT FROM AUTHOR]

The dynamic responses and load sharing features of a two-path split torque gear transmission system are investigated in this study. The possible combinations of shaft angles to ensure the gear pairs work properly are determined considering the adjacency relationship, concentric relationship, geometrical conditions and installation conditions. A dynamic model of the system considering time-varying mesh stiffness, backlash, static transmission error, stagger angle excitations and gyroscopic effects of gear body and flexible shaft is proposed. The natural characteristics of the system including natural frequencies and critical speeds are obtained. The influences of the shaft angle, asymmetric transmission error excitations and right-to-left stagger angle of double-helical gear teeth on the dynamic transmission error responses and load sharing features of the two-path split torque gear transmission system are investigated. Several references to determine the system parameters to improve the transmission property and load sharing performance of the system are provided based on the numerical simulation results. [ABSTRACT FROM AUTHOR]