Study On The Solar Blind Ultraviolet Detection And Photoelectric Guidance Technology For Helicopter Landing

In order to warn against the incoming missile and improve the safety of helicopter landing, the missile approach warning system and assistant landing system have been equipped on shipboard helicopter. In this dissertation, the solar blind ultraviolet detection technology applied in warning system and photoelectric guidance technology for helicopter landing applied in assistant landing system are studied respectively with the photoelectric detection theory.In this dissertation, the basic theory, development and research status of the solar blind ultraviolet detection technology and photoelectric guidance technology for helicopter landing are described, and the solar blind ultraviolet detection experimental system and photoelectric guidance experimental system for helicopter landing are designed respectively. From the theory and experiment, the target locating method and theoretical model of detection range for solar blind ultraviolet detection system as well as the combined locating algorithm with two-side imaging applied in photoelectric guidance system for helicopter landing are deeply studied.The composition and principle of the solar blind ultraviolet detection system are analyzed. With the intensified charge coupled device (ICCD) as the imaging device, solar blind ultraviolet detection experimental systems are designed. For the distortion negligible solar blind ultraviolet detection system, the azimuth can be determined by calculating the target imaging position on the target surface of imaging device. For the wide-angle solar blind ultraviolet detection system, successful target locating is achieved by adopting artificial neural networks to avoid the direct correction of lens distortion as well as establishing and training the back propagation (BP) network. From the perspective of energy transfer, the theoretical model of detection range for solar blind ultraviolet detection system is established based on the target face illumination of imaging device. With the reference to the analysis method of detecting distance for staring infrared search and track system, the theoretical model of detection range for solar blind ultraviolet detection system is established based on the signal to noise ratio.With the application of the designed solar-blind ultraviolet detection experimental system, the target locating method and theoretical model of detection range for solar blind ultraviolet detection system are studied. When the distance between deuterium light source and detection system is about 50m, for the distortion negligible solar blind ultraviolet detection system, the measurement errors of the horizontal azimuth and vertical azimuth for the deuterium light source relative to the optical axis of detection system can be within±0.5°; while for the wide-angle solar blind ultraviolet detection system, the measurement errors of the horizontal azimuth and vertical azimuth for the deuterium light source relative to the optical axis of detection system can be within±0.8°. The calculated values from the theoretical model of detection range are consistent with the practically measured values. The experimental results show that the proposed method for target locating is accurate, convenient and easy, while the established theoretical model of detection range is correct. Both have important theoretical and practical value.The combined locating algorithm with two-side imaging is proposed. Based on the principles of photogrammetry, the theoretical model of combined locating algorithm with two-side imaging applied in photoelectric guidance system for helicopter landing is established and the derivation procedure of theoretical model is depicted in detail. For the equations of the theoretical model, its linear solution can be got with the single value decomposition (SVD) method and least squares method, and optimized by Newton - Simpson iterative method so as to get the optimum solution. The numerical simulation calculation for the theoretical model is completed and the simulation results show that the theoretical model of combined locating algorithm with two-side imaging established in the dissertation is correct.The photoelectric guidance experimental system for helicopter landing is designed. With the application of this system, the experimental verification for the combined locating algorithm with two-side imaging is conducted. The experiment results show that when the two cameras are separated between about 16m, 20m and 26m, for the photoelectric guidance experimental system, the distance measurement errors can be within±5cm, and the angle measurement errors can be within±3°.The system measurement accuracy is close to the specifications of Canadian aircraft ship integrated secure and traverse (ASIST) guidance system for helicopter landing. The experimental system and results have important military value for the further study of engineering systems.