The Key Technology Research And FPGA Implementation Of Multi-LEO Satellites Rake Receiver

From the first satellite launching satellite’s communication has been developed for decades. Even though our country has a breakthrough in satellite’s communication technology, most technology of the commercial and military communication satellites are in the hands of the foreign countries. There is a big gap between our country and the foreign countries.At the same time, in the aspect of satellite’s communication technology, there is some different between the satellite’s communication and ground communication,such as lower SNR, more code delay and larger deviation problems, how to quickly acquisition signal, recovery and get the needed data is what we should overcome. So the communication technology on the ground can not be completely copied to satellite’s communication. Taking the difficulties in the gaps and technical aspects into account, it is necessary to carry out related research and proven for the satellite’s communication to provide relevant theoretical research and design.This paper firstly introduces the status of satellite’s communication, and describes the technical problems encountered.By these issues in satellite’s communication, introduced the commonly used Spread Spectrum technology. And then mainly presented the most important code acquisition algorithm which can be used in the environment of satellite’s communication——Part Match Filter and Fast Fourier Transform (PMF-FFT) algorithm. And next described the theory of the trace loop and multipath merge. At last, after related theory introduced,by using the FPGA programming language to realize the modules of code acquisition, code phase trace and frequency trace. And all of these modules have be tested with software and hardware, their logical functions are all right.This paper’s main innovations are in the hardware implements as followed:1. The aspects of whole PMF-FFT module——based on the theory the implements of the module has be modified, increased this algorithm’s processing speed and balanced the usage resources of hardware.2. In the module of code trace, the main innovation is the phase discriminator module. this module in this paper abandon the common method of LUT, and adopt the convergent iterative procedure.3. In the module of frequency trace, the main innovation is the frequency generator, this module’s realized method is improved from the original way, and this modified module used less resources of hardware than the common implements.