Satellite Ground Station System Based On Software Radio Technology Research And Design,

Software radio is the third-generation wireless communication technology afterwards analog communication and digital communication technology. It is a new trend in military and commercial radio development in 21st century. This paper is aimed at researching software radio satellite ground station systems design: based upon the CX-1 LEO micro-satellite ground station system design application background, using software radio concept to design the system scheme and process engineer implementation. This paper also studies the software radio key techniques including direct digital frequency synthesizer and software adaptive symbol synchronization method in the case of non-integer sampling deeply, and gives the preliminary scheme of the second generation software radio satellite ground station system.At first, this paper provides the overview of the software radio technology and its application on satellite ground station in whole world. On the basis of it, this paper presents the new idea of using software radio concept to design CX-1 LEO micro-satellite ground station system design and provides the detail implementation scheme. Since CX-1 LEO micro-satellite portable ground station putting into operation of, it is proved that this system has improved on the conventional system, it will reduce the cost of system, improve the system flexibility and inter-operability.Presently, there needs high efficient and high performance DUC/DDC for software radio receiver. Usually, the implementation of DUC/DDC applies lookup table approach. This paper compares some implementation algorithms of sine generator, provides to apply CORDIC algorithm on implementation of them compare to traditional look-up table approach, analyses the performance and error of this algorithm and gives simulation results. DDFS based on CORDIC algorithm overcomes the disadvantage of DDF S must have huge size of lookup table and no addition multiplier required, suited for hardware implementation. Thus, software radio DDFS based on CORDIC algorithm can help to reduce chip area, power dissipation and cost. These advantages are very suitable for multi-mode & multi-services application of the second generation software radio satellite ground station system.Because in a multi-band, multi-mode & multi-services wireless communication system the symbol rate of each subsystem is different, using common system clock for several target systems will lead to system clock is non-integer for all symbol rate. Our second generation SDR satellite ground station system is just about this case. Aiming atsuch case, this paper adopts a new symbol timing synchronization method which can track optimum symbol timing adaptively without redundant hardware. This paper analyzes the principle of the adaptive symbol timing synchronization method and gives the simulation results. It has some reference value for researching it during further step.Software radio is very suitable for new algorithm and new scheme applying in systems. To adapt the second generation satellite communication receivers' trend that can provide multi-services including communication and positioning, this paper bases upon the available CX-1 LEO micro-satellite portable ground station and combines the former research, provides one the second generation satellite ground station communication system software radio implementation scheme. Therefore, the function and performance of the first generation satellite ground station have been enhaced and improved.Based on the common characteristic between communication systems, the research results of key techniques of software radio in this paper have some practicability and can be generalized widely applying in the satellite mobile communication systems, third-generation wireless communication and wireless network systems.