不同电离层改正模型的SF-PPP定位精度分析

The performance of SF-PPP corrected by different ionospheric models

  • 摘要: 电离层延迟可严重制约单频接收机的定位精度. 基于此,本文介绍了四种单频接收机常用的电离层延迟改正方法,包括广播电离层改正模型(策略1),顾及太阳位置的变化全球电离层格网产品(Global Ionosphere Map,GIM)时间旋转内插(策略2),GIM投影函数改正(策略3)和半合改正模型(策略4). 同时,选择不同太阳活动期,不同纬度的测站验证不同电离层改正方法的单频精密单点定位(single-frequency point positioning,SF-PPP)定位结果偏差. 经过对比分析,得到如下结论:1)总体来说,半合改正模型得到的定位效果最佳,其次是使用GIM产品对电离层延迟进行改正,最后是广播电离层模型;2)在不同太阳活动跃期,不同策略在低纬度测站的定位偏差最大,其次是高纬度测站,中纬度测站的定位偏差最小;3)策略2和策略3在不同太阳活动期不同纬度测站的水平定位平差约0.150 m,三维定位偏差约0.700 m;策略4在不同太阳活动期不同纬度测站的水平定位偏差为0.100 m,三维定位偏差为0.500 m.

     

    Abstract: Ionospheric delay can seriously affect the positioning accuracy of single-frequency global navigation satellite system (GNSS) receiver. Thus, this paper assessed the positioning error of single-frequency GNSS receiver corrected by four commonly used ionospheric delay correction methods, i.e., broadcast ionospheric correction models (strategy 1), time-rotation interpolation of Global Ionosphere Map (GIM) considering the variation of the position for the sun (strategy 2), GIM corrected by ionospheric mapping function (strategy 3), and half-sum correction model (strategy 4). Meanwhile, the correction results of different methods for the single-frequency precise point positioning (SF-PPP) were evaluated by using the data collected by ground-based GNSS stations over different latitudes on solar condition days. The assessment results were listed as follows. 1) The positioning error of SF-PPP corrected by the half-sum correction model was the best, then was the ionospheric delay corrected GIM. The positioning error corrected by broadcast ionospheric model was the worst. 2) On different solar condition days of each strategy, the positioning error for low-latitude stations was the largest, the was high-latitude stations. The positioning error for mid-latitude stations was the smallest. 3) The horizontal positioning error of strategy 2 and strategy 3 was about 0.150 m over different latitudes on different solar activity periods, while the 3D positioning error is about 0.700 m. The corresponding errors were about 0.100 m and 0.500 m for strategy 4.

     

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