利用GPS雙頻觀測資料進行電離層單層模型適切高度之研究－－以臺中市為例

Using Kalman Filter Algorithm To Build Real-Time Regional Ionospheric Model -A Case Study of Taichung City

本文利用臺中市連續運行基站的GPS觀測資料建立區域性電離層模型，分別測試不同薄球殼高度單層模型在不同時段中造成電離層延遲誤差及對定位精度的影響，首先選用350km、400km及450km等3個不同的薄球殼高度來建立區域性電離層模型，並與IGS全球性電離層模型進行比較，結果顯示前述3種薄球殼高度的區域性電離層模型與IGS全球性電離層模型24小時間的變化趨勢大致相同，其中當薄球殼高度每增加50km，則電離層全電子含量平均約提高3.2TECU。最後透過每增加十公里為間隔計算出電離層適切高度間隔，結果顯示台中地區2015年電離層單層模型適切高度為390公里~420公里。

In this article, observation data obtained using GPS at a continuously operating reference station in Taichung were used to build regional ionospheric models. In addition, a single-layer model was utilized to test the hypothetical thin spherical shell heights at different time periods to assess the ionospheric delay errors created and the effects of these errors on positioning accuracy. First part of the article, three thin spherical shell heights (350, 400, and 450 km) were selected to construct the regional ionospheric models, which were subsequently compared with the IGS global ionospheric model. The experiment results showed that the regional ionospheric models fabricated using the three thin spherical shell heights displayed trends similar to those of the IGS global ionospheric model. Accordingly, this result hypothesized that an increase of thin spherical shell height by 50 km in the thin ionospheric model increases electron content by an average of approximately 3.2 TECU. Finally hypothesized that an increase of spherical shell height by 10 km to single-point positioning test the experiment results showed that the regional ionospheric models appropriate height of Taichung City was 390~420km.