基于站际历元二次差模型探测与修复周跳的新方法

A New Method to Detect and Repair Cycle-slip Based on A Double-differenced Model for Receivers and Epochs

周跳探测与修复是高精度动态GPS定位的关键技术之一,直接影响模糊度在航解算的效率。针对动态相对定位中周跳探测方法"三差法"的不足,提出一种基于站际历元二次差模型进行探测与修复周跳的新方法。首先对站际历元间二次差观测值进行粗差探测,以确定发生周跳的卫星以及周跳初值;然后基于残差平方和最小原则搜索周跳备选组合并修复周跳。理论分析和实验结果均表明,当有效共视卫星多于4颗时,大多数情况下,新方法可以准确定位并修复周跳。

Cycle-slip detection and correction is an important issue in high precision kinematic GPS positioning, which seriously affects the efficiency of solving ambiguity on-the-fly. A new algorithm avoiding the shortcomings of triple-differenced methods to detect and repair cycle-slip based on double differenced model between receivers and epochs is proposed. First, outlier detection is used to locate the possible cycle-slip affected double difference, carrier phase observations, and the initial cycle-slip value can be determined. Finally, a cycle-slip optional combination search approach, based on the principle of least sum of squared residuals, was adopted to repair the cycle-slip. Theoretical analysis and experimental results show that cycle-slips can be located and repaired accurately with this new algorithm in most cases, when the number of effective observed satellites was not less than four.