| With the development of photoelectron technology, computer technology and modern communication theory, the quantum communication technology has gradually become an emerging science changing human cognition of science since the 21 st century. It is a kind of communication technology which can guarantee the absolute security of information that current communication technology is difficult to solve. The technology of quantum key distribution as a key field of practicability of quantum communication technology is receiving more and more attention.This paper focused on the motion platform attitude tracing of quantum key distribution system in free space, mainly studied the space transfer process of polarization vector during the distribution of quantum key under moving environment. This paper analyzed the access technology of polarization vector, and get the moving information of pitch, azimuth and roll of the motion platform and realized simultaneous tracking of moving target and the measurement of polarization vector with orthogonal polarization beacon light as the motion platform attitude and the measurement carrier changed by polarization vector, and through measuring the 3D attitude of beacon light by sensor of 2D photoelectric position. For the measurement principle of 3D attitude of the sensor of 2D photoelectric position, deep theoretical analysis and simulation were carried out, and mathematical model of the measurement of three dimensional attitude of single device was established. Through the experiment of position measurement, polarization measurement and 3D attitude measurement, the feasibility of method of 3D attitude measurement was verified. At the same time, field tests were carried out for different motion platform in the Qinghai Lake and Mount Putuo, the characteristics of car motion platform, hot air balloon motion platform and airborne motion platform were analyzed, and the original ATP system in quantum key distribution system was improved which increased the link of initial point, and improved the efficiency of tracking, trapping and aiming of system. For the tracking strategy, symbolic method was introduced to control vector. Stable, self-adaptive tracking control process was achieved and the disadvantage of original PID control method in exploratory modification of control parameters was improved according to different symbol vectors producing different control strategies. For the signal processing, a kind of alternating hybrid type of morphological filter was designed by using the method of morphological filtering, and the rapid and stable filter output of single was realized.This paper mainly analyzed and discussed the attitude measurement and tracking method of motion platform of the quantum key distribution system in free space from the perspective of engineering technology, studied and demonstrated the key technology, tested and simulated the achievement of 3D attitude of moving targets, and promoted engineering development of the motion platform of quantum key distribution technology based on the support from the major item of knowledge innovation project of Chinese Academy of Sciences.Innovation points of the whole paper include1) Based on the method of 3D attitude measurement of 2D photoelectric position sensor of amplitude method to complete the azimuth and pitch(range of ±15°, resolution of 0.005°) of beacon light and synchronous measurement of polarization vector(range of 0~90°, the best resolution of 0.1°), put forward the deep theoretical analysis of the transmission behavior of polarized light and carry on theoretical derivation and software simulation of the application of lateral photoelectric effect of 2D photoelectric position sensor in 3D attitude measurement.2) Based on the tracking control strategy of symbolic method, different control strategies will be produced through the establishment of symbol vectors, and the tracking process of controlled parameters will be completed by controlling actuators, the disadvantage of routine PID control method in exploratory modification of control parameters will be improved, and the stability and self-adaptability of the control process will be improved.Under the large load condition, the tracing error is ±0.1°.3) Base on the method of signal filtering of morphology, alternating hybrid type of morphological filter will be established through selecting multi-type structural elements to realize a rapid filter output of signal.4) For the experimental analysis of the characteristics of motion platform, the movement parameters and Spectrum composition of different motion platform will be obtained through the test of car, hot air balloon and airborne motion platform thus to guide the design and technical improvement of ATP tracking system. |
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