Design And Implementation Of Digital Satellite-Based Spread Spectrum Receiver

Unified Carrier Telemetering and Command System is made use of in spaceflight tasks now. However, its efficiency, anti-jamming ability and multiple-access ability cannot meet the demand of increasingly heavy spaceflight tasks.. Meanwhile, Spread-Spectrum technology has the ability of ensuring efficient data communication in the condition of powerful noise and low SNR, and is known as new communication method with low intercepting possibility, strong anti-jamming ability and high security. At the same time, PN code telemetering is the main method in space telemetering with its various advantages. Thus, it is the inevitable trend that spaceflight telemetering and command system in our country will turn to unified spread-spectrum system. In this way, we have done some work on satellite-based spread-spectrum transponder to design one sort of digital transponder, the universality and flexibility of which can satisfy the requirements.Field Programmable Gates Array(FPGA) is one of new digital processor which can be applicable in realizing software radio architecture. The thesis proposed one scheme of spread-spectrum receiver based on IF sampling in light of software radio, and also the method of realizing such key algorithms, such as digital downconvertor, PN code synchronization, carrier recovery, very long telemeter PN code synchronization leaded by short PN code and so on, based on the architecture of FPGA plus DSP. Optimization of hardware implementation in line with features of devices is also introduced.