利用中心差分法进行GPS定速时最佳点数的选取

Optimal Points of Using Central Differences Method for GPS Velocity Determination

摘要: 分析了利用中心差分法进行GPS定速时的主要误差来源,证明了当数据采样率一定时,增加中心差分法的点数可减少微分过程中的截断误差,但同时会放大导出相位率的观测误差,得出中心差分法的最佳点数应使这两种误差之和最小的结论。实验结果表明,当数据采样间隔为1s、载体平均速度和加速度为20m.s-1和0.2m.s-2时,9个点的中心差分法定速精度最高。

Abstract: Three points central differences method(CDM) has been widely used in GPS velocity and acceleration determination.However,it will lead to a considerable error when the carrier has a strong maneuverability.We prove that the truncation errors will be decreased and observational errors will be increased when more points be used in CDM.For validation of our analysis,some airborne GPS data are used.The results show that if data interval is 1 Hz,average velocity and acceleration of carrier is 20 m·s-1,0.2 m·s-2 respectively,9 points CDM is the best.Comparing of common using 3 points CDM,the precision of velocity determination is improved about 40%.And the improved level is more significant when the carrier has a strong maneuverability.