探究不同纬度对北斗电离层延迟的影响

Exploring Effect of Different Latitudes on Beidou Ionospheric Delay

针对不同用户需采用不同的电离层延迟模型。适用于单频用户的Klobuchar模型,考虑了该模型的振幅、周期和夜间延迟值随时间变化的特性,并加入太阳相对黑子数这一变量,建立其改进模型;而对于双频用户的格网电离层模型,选用不同纬度参考站,根据格网点与穿透点的位置关系,采用反距离加权法和克里金内插法(KRG)估算参考面格网点的电离层垂直延迟误差,仿真分析了格网点电离层垂直延迟修正误差(GIVE);结果表明,Klobuchar改进模型修正电离层延迟误差精度效果显著;而格网电离层模型校正的精度变化和纬度变化相关,低纬度地区格网改正效果更接近实测值,修正误差也在正常范围内,中纬度地区改正精度相对较差,可使用KRG内插法的格网模型修正延迟误差。

Different ionospheric delay models need to be used for different users.Klobuchar model for single-frequency users,taking into account the characteristics of the model's amplitude,period and nighttime delay value changes over time,and adding the sun relative sunspot number of variables to establish its improved model.For the grid ionosphere models of dual-frequency users,different latitude reference stations are used.According to the positional relationship between grid points and penetration points,inverse distance weighting method and Kriging interpolation method(KRG)are used to estimate the reference grid points.The ionospheric vertical delay error,and the grid point ionosphere vertical delay correction error GIVE.The results show that Klobuchar improved the model to correct ionospheric delay error accuracy significantly.The accuracy of grid ionosphere model correction is related to latitude variation.The effect of grid correction at low latitudes is closer to the measured value,the correction error is within the normal range,and the accuracy of correction in the mid-latitude region is relatively poor.KRG interpolation can be used.The grid model corrects the delay error.