الفهرس | Only 14 pages are availabe for public view |
Abstract Satellite ranging, which is the task of determining the slant range between the satellite and its ground control station, is a vital process, which is used in satellite tracking and determination of its orbit. This study includes a number of topics: chapter one reviews the range determination methods in general and particularly for satellites, and outline of the ranging signal design used. It was found that the ranging method that uses pseudo random sequences as the ranging signal is the most suitable and accurate method. Chapter two is concerned with the choice of certain ranging method and designing of the used ranging code to satisfy the ranging determination requirements such as the maximum satellite range, range resolution, easy and fast acquisition of the ranging code, and difficulty of interceptability. This chapter also overviews the different types of pseudo random sequences used in ranging, concerning their different properties and generation methods. Chapter three reviews and studies the methods of acquisition of the pseudo random sequence (PRS), which is the phase that precedes the PRS sequence tracking phase during the communication session with satellite. The acquisition phase includes a study of the probability of failure in acquiring the PRS, and study of the probability of acquisition by two methods. The acquisition process was also programmed on FPGA. Chapter four is concerned with the PRS tracking by using digital delay-locked loop (DLL). This chapter also includes, a study of the DLL with its components and the design equations for each |