| Our territory is vast and grid has a large coverage area. The grid blackouts events caused by natural disasters have occurred usually and the traditional meansof communication in disaster electricity extreme cases can not be guaranteed towork,therefore, based on the power grid emergency satellite communicationsplatform is an essential complement to the grid.This paper make full use of the satellite communication,high dynamic channelcharacteristics in LEO satellites,direct sequence spread spectrum technology,spreading code synchronizations, Doppler shift compensation and other theoreticalknowledge. The composition of emergency communications platform based on gridsatellite communications systems,the influence on the spread code synchronizationof low-noise ratio high dynamic conditions,the spreading code acquisition,and its rateof change of the Doppler shift compensation and other key technologies are studied inthis paper also.Focuses on the analysis of the capture high dynamic signal for LEOsatellite communication technology, the new Doppler frequency estimation algorithmadapted for different conditions,the new signal capture algorithm based on thepre-correction of Doppler frequency shift and the new code acquisition algorithm ofshort code and long code are proposed in this paper,and the algorithm based onnon-coherent accumulation matched filter is improved in this paper to improvereception performance synchronous systems under high dynamic conditions.Theresearch results laid the theoretical foundation for satellite signal synchronousreception under the high dynamic conditions,therefore it has important significance forself-development and construction of power grid emergency communication system. |
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