Senior capstone: A software defined radio design for amateur astronomy

This paper describes a unique interdisciplinary Senior Design Capstone project to design and implement a Software Defined Radio (SDR) receiver that emulates the hardware-based NASA-specified Radio JOVE system. Radio JOVE receivers are used by amateur astronomers to detect and record Jovian radiation and solar radiation from the sun over the decametric band of 3MHz to 40MHz. Our SDR system is designed to work at 20.1MHz with a bandwidth of 1MHz. As the culminating experience of our undergraduate program, this capstone project was sponsored by physics astronomers and required our group of three students to demonstrate expertise in RF, signal processing, FPGA-based digital design, Linux USB interfacing and high-level software. Included in the design and implementation are the RF-based analog front end (bandpass filtering and level adjustment), digital board (ADC, digital down-conversion and data interface) and the PC-based software GUI (further signal processing and user interface). Of particular challenge were the high precision requirements along with fairly high speed throughput all while maintaining a low price-point. A custom solution to data formatting was employed while then taking advantage of the freeware GNU Radio toolkit at the back end. Preliminary field trials have demonstrated the system's viability. Included in this paper are detailed discussions of the design and implementation along with certain key performance metrics.