基于RFSoC的球载甚长基线干涉测量实验后端与授时系统
An RFSoC-based Backend and Timing System for the Balloon-borne Very Long Baseline Interferometry Experiment
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中文总结 AI 辅助
本文介绍球载VLBI实验BVEX的RFSoC数字后端与授时系统，采用4.096 GSPS采样和8.2 Gbps记录，首次部署于平流层气球，地面测试通过，2025年飞行失败，计划2027年再飞。
中文摘要 AI 辅助
我们介绍了球载甚长基线干涉测量实验（BVEX）的数字后端与高精度授时系统的设计与性能表征，该实验是22 GHz平流层甚长基线干涉测量的探路者。后端使用AMD-Xilinx RFSoC 4x2上四个14位模数转换器输入之一。尽管转换器支持高达5 GSPS的采样率，飞行配置以4.096 GSPS对2-4 GHz中频进行数字化。CASPER固件提供用于指向和接收机验证的高分辨率光谱仪，以及具有两位重新量化的VLBI采集链，记录速率约为8.2 Gbps。带时间戳的数据包通过100千兆以太网（GbE）发送到存储计算机中的16 TB NVMe阵列，该计算机功耗约为70-80 W。授时链使用Rakon恒温晶振作为授时参考，而时间间隔计数器以约60 ps的分辨率测量其相对于GPS参考的漂移。这是RFSoC基VLBI后端与高精度授时系统首次部署在平流层气球上。地面测试验证了后端、光谱仪和授时链。2025年8月的CSA STRATOS飞行因气球故障而未达到目标浮空高度，因此未获得科学观测数据。对于计划中的2027年再飞行，我们正在开发一款传导冷却的数据存储计算机，具有24 TB NVMe容量，并提供从100 GbE接口到NVMe阵列的直接数据路径。
英文摘要
We present the design and performance characterization of the digital backend and precision-timing system for the Balloon-borne Very Long Baseline Interferometry Experiment (BVEX), a pathfinder for high-frequency stratospheric VLBI at 22 GHz. The backend uses one of the four 14-bit analog-to-digital converter inputs on an AMD-Xilinx RFSoC 4x2. Although the converters support sampling rates up to 5 GSPS, the flight configuration digitizes the 2-4 GHz intermediate frequency at 4.096 GSPS. CASPER firmware provides both a high-resolution spectrometer for pointing and receiver verification, and a VLBI acquisition chain with two-bit requantization that records at a rate of about 8.2 Gbps. The timestamped data packets are sent over 100 Gigabit Ethernet (GbE) to a 16 TB NVMe array in a storage computer that draws approximately 70-80 W. The timing chain uses a Rakon oven-controlled crystal oscillator as a timing reference while a time-interval counter measures its drift relative to a GPS reference with approximately 60 ps resolution. This is the first deployment of an RFSoC-based VLBI backend and precision-timing system on a stratospheric balloon. Ground tests validated the backend, spectrometer, and timing chain. The August 2025 CSA STRATOS flight ended before reaching the target float altitude because of a balloon failure, and as a result no science observations were obtained. For the planned 2027 reflight, we are developing a conduction-cooled data storage computer with 24 TB of NVMe capacity and a direct data path from the 100 GbE interface to the NVMe array.
发表机构
- Queen’s University（女王大学）
- Harvard University（哈佛大学）
- Center for Astrophysics | Harvard & Smithsonian（天体物理中心 | 哈佛与史密森尼学会）
- MIT Haystack Observatory（麻省理工学院海斯塔克天文台）
- McGill University（麦吉尔大学）
- Trottier Space Institute at McGill（麦吉尔大学特罗蒂尔太空研究所）
- StarSpec Technologies Inc.（StarSpec科技有限公司）
- Johns Hopkins University（约翰斯·霍普金斯大学）
机构由 AI 辅助整理，请以论文原文为准。
