Comparison of 4D tomographic mapping versus thin-shell approximation for ionospheric delay corrections for single-frequency GPS receivers over North America
Comparison of 4D tomographic mapping versus thin-shell approximation for ionospheric delay corrections for single-frequency GPS receivers over North America
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DOI：
10.1007/s10291-009-0153-0
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发表时间：
2010-06
期刊：
影响因子：
4.9
通讯作者：
Damien J. Allain;C. Mitchell
中科院分区：
文献类型：
--
作者：
Damien J. Allain;C. Mitchell
大多数导航卫星接收器工作在单一频率上。它们使用通常只修正50%延迟的电离层模型或电离层薄壳图来补偿电离层延迟。使用四维层析成像技术绘制了2003年秋季北美上空电离层全高度上的自由电子密度图。本文比较了基于薄壳图和基于全高图的改正计算的导航解。这些地图被用来计算北美选定位置的GPS接收器在L1频率上经历的多余传播延迟。应用额外的延迟来校正每个位置的单频伪距观测，并计算得到的定位的改进。结果表明，薄壳MAP和全高MAP的性能几乎与双频载波平滑基准一样好，而对于大多数接收机来说，都好于未滤波的双频基准。全高度修正效果很好，在极端风暴条件下比薄壳修正要好得多。
The majority of navigation satellite receivers operate on a single frequency. They compensate for the ionospheric delay using either an ionospheric model which typically only corrects for 50% of the delay or a thin-shell map of the ionosphere. A 4D tomographic imaging technique is used to map the free electron density over the full-height of the ionosphere above North America during autumn 2003. The navigation solutions computed using correction based upon the thin-shell and the full-height maps are compared in this paper. The maps are used to calculate the excess propagation delay on the L1 frequency experienced by GPS receivers at selected locations across North America. The excess delay is applied to correct the single-frequency pseudorange observations at each location, and the improvements to the resulting positioning are calculated. It is shown that the thin-shell and full-height maps perform almost as well as a dual-frequency carrier-smoothed benchmark and for most receivers better than the unfiltered dual-frequency benchmark. The full-height corrections perform well and are considerably better than thin-shell corrections under extreme storm conditions.