我国探月工程VLBI相关处理机简介

An Introduction to the VLBI Correlator Used in the Chinese Lunar Exploration Program

甚长基线干涉测量(VLBI)是重要的射电天文技术,具有极高的空间分辨率,是国际上广泛采用的深空探测器高精度角位置测量手段。相关处理机是VLBI数据预处理的核心设备。由于VLBI观测数据的相关处理具有数据密集和计算密集的双重特点,普通计算机的性能难以达到对数据处理速度的要求,需要有专用的高速硬件数据处理单元来完成相关处理。我国探月工程VLBI地面测控系统中所使用的硬件相关处理机是基于大容量、高性能的在线可编程门阵列(FPGA),自主研制的高速数据处理单元,可以实时处理每台站最高速率达1 Gb/s的数据,其数据处理结果,经过软件验证并与欧空局(ESA)提供的数据进行了比较,结果符合良好。

As a radio astronomical technique with very high angular resolution, Very Long Baseline lnterferometry （VLBI） has been widely used in the high precision deep space probe tracking activities. The VLBI correlator is one of the key data-preprocessing device. Since the correlation process in VLBI has the characteristic of intensive data and computation, ordinary computer can hardly achieve the request for high speed data processing. Therefore, a specially desined high-speed hardware correlator is normally needed. The hardware correlator used in the Chinese Lunar Exploration Program （CLEP） is an independently developed, high-speed data processing system based upon Field Programmable Gate Array （FPGA） with large volume and high performance, which can deal with data up to 1Gbps per station at real time. The result is good through validations with soft correlator and data from ESA.