Skin Satellite Micro Ground System Of The Study

Pico-satellites have advantages of high self-control degree, low weight (1kg or lighter), small size, high functional density and short R&D period. It can be used in communication, navigation and deep space exploration. It has been a hotspot for many countries after nano-satellite. "One-rocket-several-satellites" is usually adopted as the launch method for Pico-satellites. The satellite cluster in the satellite orbital covers some range in the way of formate. Satellites share resources and information with each other, realize functions together, such as stereo imaging, distributed aerospace measure, etc. And they can realize space science experimentation with lower cost, such as satellite carry test.This thesis analyzes the Ground System for Pico-satellite. The Ground System is used to detect and control the Pico-satellite, which is an indispensable system. The performances of Pico-satellites will be shown from the associated debugging with the Ground System. The works in this thesis are following:(1) The forward-AGC and feedback-AGC used in the Ground System is analyzed and compared. And following conclusions can be drawn. The dynamical range of forward-AGC is more affected by the gain slope of the gain-controllable intermediate frequency amplifier than that of the feedback-AGC. The control precisions of both AGCs can be high, but the forward-AGC is more sensitive to system parameters than the feedback-AGC. And the response time of the feedback-AGC is shorter than the forward-AGC. So the feedback-AGC has wider application range. The analytical results were verified by the experiments. The optimized feedback-AGC circuit in this thesis has dynamical range of 65dBm and control accuracy of 0.2%.(2) The BPSK modulator is designed by DDS technology. The frequency of vice carrier can be programmed. The circuit structure is simple and the performance is stable. BPSK demodulator is accomplished by coherent demodulation. The carrier synchrony is finishedby the square-loop method and bit synchrony is realized by filtering.(3) Range acquisition is an important function of satellite system. This thesis introduces design of side tone range acquisition signal and phase trace theory. The range acquisition scheme for the system is presented firstly. Then the effect of the system to range acquisition signal is analyzed. The acquisition results between close loop of the Ground System and associated debugging with Pico-satellite is compared too. Finally, the error source of phase fluctuation is analyzed.(4) The function modules of the Ground System is presented in detail. The miniaturized Ground System is achieved finishing. When associated debugging with Pico-satellite, the Ground System is succeeded to emit data, receive and retrieve images taken by the on-satellite CMOS camera clearly. However, when the data code is a sequence of zeros, the receiver will not decode correctly. This problem is solved using interfering code and the EBR is reduced significantly.The Ground System for Pico-satellite has been developed successfully. The emitting power of the Ground System is 20dBm, the sensitivity of tracing and capturing is -89dBm, the dynamical range is more than 55dB and the capturing time is 28ms. In the test of overall-system of the Pico-satellite and the Ground System, the images can be received and retrieved well. And range acquisition can be realized fundamentally.