新一代厘米——分米波射电日像仪系统延时校准方法研究

摘要

The Chinese Spectral Radioheliograph (CSRH) is a solar-dedicated radio interferometric array that will produce high spatial resolution,high time resolution and high frequency resolution images of the sun simultaneously in cm-dm wave range. The quality of the calibration is the key for imaging especially for the case of ultra-wideband, high time resolution and frequency resolution in design and implementation. In this paper, we choose the sun as calibration source and calculate the delay for different geographical latitude and longitude. As a result,the delay accuracy that we got is better than 1ns.%射电日像仪是采用综合孔径方法成像,具有高时间、高空间和高频率分辨率的太阳专用射电望远镜.为了使信号相关值准确,需要精确测量系统的延时,在太阳成像相关前扣除,消除消调函数对可见度函数值的影响.同时延时的测量精度影响数字补偿精度、图像信噪比等信息,是其成像质量的关键,也是超宽频带和高时间分辨率情况下研制和实施的难点.本文研究了应用于我国在建的厘米——分米波射电日像仪,以太阳为校准源,闭合差方法得到系统延时差,并通过试验验证,得到优于1ns补偿精度.