Distributed Synchronous Acquisition for Next-Generation Heliograph

The radioheliograph employs synthetic aperture imaging techniques to achieve high-resolution observations of the Sun. Enhanced synchronization among the antenna elements significantly improves the dynamic range of the resulting images. This paper presents a digital receiver system designed for solar radio observations, which utilizes a rubidium atomic clock to ensure precise synchronization. Combined with high-accuracy delay compensation, the system implements a fully digital and distributed synchronous acquisition architecture. The processing core is based on a XCKU115 FPGA, which enables high temporal resolution (< 1 ms) and high spectral resolution (< 3 MHz)—both essential for accurate radio spectral measurements. Experimental results demonstrate that the system achieves two-level, four-scale delay compensation with an error of less than 10 ps, while the overall timing accuracy across the full signal chain remains about 100 ps. This work provides a foundation for the development of next-generation radioheliographs, offering high applicability and system scalability.