相关处理软件系统中模型计算的精度分析

ACCURACY ANALYSIS ON MODEL CALCULATION IN CORRELATOR SOFTWARE PACKAGE

介绍了由上海天文台主持研制的“中国VLBI网宽带相关处理机”中模型计算的实现过程 ,基于相关处理机条纹搜索窗口的大小讨论了对模型精度的要求。应用测地VLBI数据分析软件包OC CAM对相关处理机模型的计算精度进行了外部检验 ,结果显示时延的符合度为ns量级 ,延迟率则小于 1ps s,这远远小于模型中的钟差和未模型化的电离层效应产生的误差。因此 ,模型精度已足以满足相关处理机条纹搜索和相关后处理的要求。

Implementation of model calculation in Shanghai correlator is described, and required model accuracy is discussed based on the size of correlator fringe search window. Geodetic VLBI data analysis software package OCCAM has been used to calculate model parameters and compared with correlator output. Results show they agree on the level of several ns in time delay and not greater than 1ps/s in delay rate, which is far below the errors contributed by clock behavior and un-modeled ionospheric effects. Thus, the model has enough accuracy to meet the demands of correlator fringe finding and post-correlation process.