W-band Radiometer NC Terminal Design

W-band passive millimeter wave detection technology has the advantages of high precision, strong anti-interference, can work all-weather, etc., and is widely used in the fields of radio astronomy, missile guidance, contraband detection, etc. Research on target radiation characteristic measurement of military targets such as tanks and aircraft, etc., and prohibited items such as guns and bombs can provide strong support for target recognition on the field of military war and public safety. As an important part of W-band target characteristics measurements, NC (Numeric Control) terminal mainly realizes the functions, including human-computer interaction, system control, data processing, etc., which has an important significance of the research project.Firstly, based on the measuring principle of millimeter wave radiation characteristics, the paper analyzes the working principle of W-band millimeter wave radiometer system; derives brightness temperature inversion model, and selects scan mode, sampling interval, spatial resolution and other system parameters. According to the system requirements, we design solutions of the NC terminal subsystem that based on the core with ARM and FPGA.Secondly, the paper designs the hardware circuit of NC terminal, specifically including power supply circuit, FPGA configuration circuit, data acquisition, switch control circuit, network control circuit, USB interface circuit, LCD interface circuit, SD card interface circuit, communication and data transmission interface circuit. The design reduces power consumption of the system greatly while ensuring the processing speed of the NC terminal.Thirdly, the paper chooses Linux operating system as the software platform, completes the transplanting of startup code (bootloader), Linux kernel, root file system; implements the writing of SPI driver and serial port driver; and transplants the driver of LCD device and network device. After the transplanting is completed, the paper tests all drivers that have been transplanted and they all can work properly.Finally, the paper completes the design and development of applications. First, we make a design and simulation for the functional modules of FPGA with the ISE development environment; then, according to the operation modes of the system, we use the Qt/Embedded development environment to design the graphical user interface of portable measurement module and imaging module respectively. Among them, the portable measurement interface realizes the real-time display of radiometer voltage curve and radiation brightness temperature; the scanning and imaging interface mainly completes operations such like servo system and imaging, and extracts the edge of the image through interface functions of OpenCV.Compared to conventional techniques, the NC terminal has a small size, low power consumption, easy operation and high maintenance. Due to its strong practicality and significance, the NC terminal provides a good solution for the measurement technique of the millimeter-wave radiation characteristic.