| The government has invested funding and personnel to build the satellite navigation system all this time, and BeiDou Navigation Satellite System is continuously booming. With the release of technical documentations of the BeiDou Navigation System, the Chinese BeiDou navigation industry officially enters a new and globalism phase of satellite navigation. Today, the ARM is payed very close attention to in the embedded development. The STM32F4series MCU of STMicroelectronics plays an important role because of its unique design and service. So the practical receiver based on STM32F4MCU not only is a simple application development, but also is dedicated to building the BeiDou Navigation Satellite System.The article mainly designs the hardware platform and the software platform of the receiver and implements it. The hardware platform of the receiver is based on STM32F4as the main controller. According to requirements of the function, the kinds of peripherals and the layout of hardware are designed including the design of all serial communications, Ethernet PHY chip DP83848I and transformers, SD card, USB interface, and so on. The domestic GNSS board is used to achieve millimeter-level RTK positioning services. The software architecture consists of five layers, the application layer, the data layer, the component layer, the system layer and the hardware layer. The application layer provides the user management and other management services. The data layer completes the conversion and distribution of raw observational data, monitors and manages tasks. The component layer receives the integrated navigation data and achieves WEB and communication services. The system layer integrates FreeRTOS, LwIP and FatFs file system to form a complete embedded system and to complete multi-process tasks. The hardware layer achieves the normal operation of every component.By relevant technologies of the BD/GPS receiver, this design has achieved a small size, low cost and very practical GNSS receiver. |
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