| NAVTEX is a system transmitting and receiving the security information offshore based on NBDP, is one of the important components of GMDSS.The traditional NAVTEX system works by NBDP, which cannot meet the requirements of the modern ocean shipping development. With the rapidly development of technology, communication systems update from analogue to digital, an improved NAVTEX system is required.NAVTEX receiver system is expatiated in this paper. According to the shortcomings of the traditional system, a new method of processing the received signal using the software radio and DSP techniques is adopted. Based on the software radio techniques, the received signal is band-pass sampled, and then the sampled signal is delivered to the DSPs which perform the functions such as filtering, demodulation and signal generating. Different processing methods are discussed and some of them are chosed to perform signal in receiver. At the same time, the DSP kit is designed and tested, the proposed method in this paper is performed in this kit, which can receive and process the NAVTEX signal.The design which is presented in this paper meets the development requirements of the modern ocean shipping and has an important effect on its economy development. The system can process the security and navigation information aptitudinally, which make it suitable for the modern shipping management requirement much more. |
