基于二次相关的甚长基线干涉测量相关处理方法

Very Long Baseline Interferometry Measurement Based on Twice Correlation

针对甚长基线干涉测量中FX相关处理方案存在对时延预测模型要求较高的问题,提出了基于二次相关的甚长基线干涉测量相关处理方法。该方法与原方法相比有两点不同:一是通过二次相关处理更新补偿整数比特延时,取代了原方案中的小数比特补偿;二是通过增加一步"一次曲线拟合"改进了野点剔除算法。仿真表明:该方法经过两次整数比特时延补偿,将两站接收信号相对时延缩小到一个比特内,从而避免了相位卷绕现象;野点剔除过程不受相位随频率变化趋势的影响,使相位分布方差更小,在一定程度上提高了相关处理的噪声容限。新方法具有时延预测模型要求低、野点剔除效果好和时延估计精度高等优点。

Of very long baseline interferometry （VLBI） measurement, the FX correlation needs high accurate prediction time, which is not always satisfied. A novel VLBI correlation method was proposed. Compared with the former scheme,this new method reduced the time-delay between different station signals to one bit less by compensating the integer bit time- delay twice, which therefore avoided phase wrapping and omits fraction compensation,and considering the delete procession was affected by the trend that phase changes according to frequency, the new method mended outlier delete algorithm by adding a linear curve fit in the typical FX correlation. Simulation proved the novel method had better delete performance and more accurate time delay estimation but needs lower prediction time accuracy.