In order to meet the design requirements of more compact and portable laser detection system, the parameters optimization design of lightweight structure is carried out for the receiving system with large quality proportion. Firstly, based on the index requirements of the system for performance and structure, the scheme of Cassegrain optical receiving system is selected, and it is clear that the receiving system is an all-aluminum card mechanical structure. Then, through the numerical analysis of the mode and static force of the receiving lens, the main reflector is selected as the optimization object. After that then the multi wheel topology optimization design is carried out by using the finite element analysis method, and the dynamic simulation analysis of the whole receiving system is carried out. Finally, it is determined that the lightweight hole form of the back opening of the main reflector is fan-shaped, the thickness is 4mm, and the weight loss rate is 31.4%. Under certain vibration and impact environment conditions, the system structure still has good stability. According to the design and optimization results, the processing and assembly of the lens are completed. Through alignment test and surface inspection, the PV value of the main reflector is 2.293λ, and the RMS is 0.509λ (λ=1064nm). Both of them meet the requirements of optical design. It shows that the accuracy of the main reflector surface improved by top1ology optimization can meet the application requirements. which has a certain reference significance for the structural design in the field of aircraft laser ranging.
In order to meet the needs of TV detection in deep sea environment, a compact continuous zoom system driven by cam sleeve is studied. Through the analysis of the system indicators, the optical system of three groups of linkage zoom and rear group for focusing is selected, and the structure of cylindrical cam driving to cooperate with the cylindrical guide sliding is clarified. Based on this idea, each module of the TV detection system is designed in detail. The design method of electric iris diaphragm in the middle of the system is proposed, and the calculation process and results of zoom drive mechanism selection are given. The method of alignment of lens optical axis adjustment with theodolite and cross-reticle is put forward. With this design and adjustment process, the TV detection system can be applied to deep sea environment is finally realized. The system has a continuously variable field of view with 5.8°~60° underwater, the F number changes from 3.5 to 16, and the whole zoom time is less than 2s. The test results show that the MTF of the center field of view at the long focal point and the short focal point are 0.4 and 0.57. Test images in laboratory and underwater scene are clear and high resolution, which shows that the imaging quality of the system is excellent. At the same time, the system is Φ 105×115mm in actual size and 860g in weight, and can be integrated into the deep-sea pressure cabin to meet the needs of deep-sea detection.
Computer vision plays a key role in measuring the relative posture and position between spacecrafts, especially in various close-range space tasks. As one of the essential steps for computer vision, camera calibration is important for obtaining precise three-dimensional contours of a space target. The focal length of on-orbit zoom cameras constantly changes. Thus, it is practical to calibrate the focal length rather than other intrinsic camera parameters. However, traditional calibration targets, such as checkerboards, cannot be used to calibrate a space camera in orbit. To address this problem, we propose a two-step process for focal length calibration. In the first step, the initial estimate of the camera focal length was generated with vanishing points obtained from the solar panels of satellites. In the second step, the initial solution was optimized by the particle swarm optimization algorithm. The results of the simulations and laboratory experiments confirmed the accuracy, flexibility, and good antinoise interference performance of the proposed method. Thus, the proposed method has practical significance for space tasks, such as space rendezvous-docking and on-orbit maintenance.
Aiming at the threats to spacecraft safety caused by space debris, and improving the stability and working life of spacecraft in orbit, it is proposed to use spacecraft equipped with a safety self-perceptual optical payload to detect space debris to improve the safety of the aircraft in orbit. This paper analyses the application methods and characteristics of the safety self-perceptual optical payload of space vehicles, and defines the technical indicators of the optical payload. The safety self-Perceptual optical payload includes the MWIR optical system with large field of view and the visible continuous zoom lens with large zoom ratio. The detector resolution is 1280×1024, the pixel size is 15μm, the focal length is 8mm, the F number is 2, and the field of view is 97.6°×85° of MWIR optical system;The detector resolution is 1920×1080, the pixel size is 5.5μm, the focal length is 15mm~750mm, which has a 50 times zoom ratio, and the field of view is 38.8°×22.4°~0.80°×0.45° of the visible continuous zoom lens. The two systems are athermal designed in the temperature range of -40°C~60°C respectively to meet the environmental requirements of space applications. Safety self-perceptual optical payload could obtain, and apperceive long-range targets in the 10km range around the space vehicle, and improve the aircraft's survival ability
KEYWORDS: Cameras, Modulation transfer functions, Optical engineering, Temperature metrology, Monochromatic aberrations, Picosecond phenomena, Thermal effects, Satellites, Signal to noise ratio
Thermal design is highly related to the performance of space cameras as temperature changes cause thermal displacements of the cameras’ optical and mechanical systems, consequently affecting imaging quality. However, most existing thermal design methods for space cameras focus on several thermal design parameters without a comprehensive and quantitative analysis. Therefore, we proposed an optimization thermal design method for space cameras based on thermo-optical analysis and the Taguchi method. We first established the thermal balance equations of space cameras, and by analyzing the thermal design parameters in the equations, we identified the key parameters that affect the temperature field, thermal displacements, and imaging quality of the camera. Furthermore, we evaluated the influence of each thermal design parameter on imaging quality based on the integrated thermo-optical analysis. Thereafter, we applied the Taguchi method to quantitatively calculate the effect of each thermal design parameter on imaging quality. Finally, we implemented an optimal thermal control scheme for space cameras based on the results of the Taguchi method. The experimental results demonstrated that the proposed method is reliable and efficient and would be beneficial to researchers working on the thermal design of optical instruments.
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