A Research Of Deep Space Receiver Base On Software Defined Radio Architecture

Deep space exploration receiver is an important part of deep space monitoring network, it realize the data sampling, data processing and data storage of the radio signal. Through the radio signal analysis and processing, people can calculate the orbit of the detector and learn the characteristics of the stars in the universe. Receivers using software defined radio architecture offen have better flexibility, openness and a longer life cycle. So software defined radio architecture is widely used by many receivers system at home and abroad and has great research and application value.The article analyzes the structural characteristics of various domestic and international radio receiver. A software defined radio receiver with ARM microcontroller, high-speed ADC and FPGA was implemented, which is called RSR-ARM (Radio Science Receiver With ARM Microcontroller). Then system stacked hardware structure was determined, and the function of the ADC, FPGA and ARM modules was introduced. On this basis, each module of the FPGA high-speed signal processing section was implemented. To facilitate further processing, a high speed serial to parallel converter was designed to slow down the rate of high-speed data from the ADC, whose sampling rate is up to GHz. Downconversion module has three levels, thus achieving a wide range, small step in the local oscillator frequency set with a smaller resource consumption. Multistage downsampling programs meet the needs of a variety of deep space exploration mission in the rate of data. Based on AHB (Advanced High performance Bus) bus, the FPGA and ARM data exchange and the bus address mapping were realized. The Gigabit Ethernet data transmission part was achieved by physical layer, data link layer and the data receiving of the host computer. The structure of RSR-ARM frame and Ethernet packet was also given in this section. Through the speed test, the Gigabit Ethernet module can achieve 512Mbps high-speed data transmission storage.Secondly, the control software for ARM-based embedded Linux system was designed and implemented. The entire software system is divided into four parts:driver layer, control layer, service layer and client layer. From the driver layer to the upper layers, the operations of hardware control and monitoring was encapsulated layer by layer. Then based on B/S (Brower/Server) architecture, it present a simple, easy-using RSR control interface to the user in the form of Web pages, which supports remote control and real-time information feedback; Plans file system allows users to set the scheduled tasks. In this way, users have no need to always pay attention to the system state and achieve more precise observation mission. In addition, the data storage task was separated from the system to the host computer Gigabit Ethernet high-speed data receiving program, which reduce the burden on the system running.Finally, the whole RSR-ARM system has been fully tested, including the input characteristics, data storage, NCO frequency range and step size and channel conformance. The final summary of system illustrate the systems is functional, flexible and easy to maintain, meet the design of the indicators.