Design Of Two Channel NAVTEX Receiver

NAVTEX system is based on narrow-band direct-printing telegraph to send and automatically receive the information system, which plays an extremely important role to ensure the safety of navigation. The traditional NAVTEX receiver adopts narrow-band direct printing (NBDP) whose functions is simple and intelligent level is not high, no longer meeting the requirements of the development of modern shipping.A dual-channel NAVTEX receiver is designed in accordance with international NAVTEX receiver's acceptance standards (IEC61970-6). The receiver can support bilingual system which can simultaneously receive information of international and domestic channels.A DSP + FPGA architecture to build the hardware platform is used. The structural is versatility and suitable for modular design which can improve the efficiency of the algorithm and easy to be maintained and extend, fulfilling the real-time signal processing requirements.In order to meet the requirements of the development of modern shipping, software_defined radio technology is adopted which use improved digital demodulation replacing traditional analog demodulator to increase the flexibility and scalability of the system. In order to better achieve human-computer interaction, the text messages are displayed on the LCD. To guarantee and improve the performance and stability of the real-time system, a interrupt-driven module is adopted and a document management system is specifically designed.The sensitivity of the system is up to -110dbm by actual detection, meeting the international standards(-107dbm). The systme has been successfully accepted information from Shanghai, Dalian and Japan's navigation.