如果一個傳統的GPS接收機使用於定位，它通常需要下載所需的導航信息( Broadcast Ephemeris and Satellite Almanac ) ，對冷啟動而言這將花費大約12.5分鐘。目前，很多研究的目標是縮短時間到首次定位為目標，以實現快速定位。
在過去許多文獻中主要皆是利用GPS衛星位置來提高定位的精度。因此在本研究中主要利用為IGS( International GNSS Service )提供之精密星曆與Bernese軟體產生之精確衛星狀態資料。在這個過程中，應用具有位置與速度觀測量之Batch濾波器轉換觀測量成傳統GPS接收器可使用之精密廣播星曆。特別是其中速度觀測量偏微分模型方面的15個廣播衛星參數是相當複雜的數學推導。因此使用真實精密星曆來確認推導正確性。結合不同衛星觀測量和採樣頻率的精密星曆進行處理，驗證衛星的準確位置。改善範圍為3至20倍之間。
在定位實驗中，不同的廣播星曆應用於精確位置的測定。其結果是，較短的觀測時間，具有衛星速度的觀測量強化了衛星定位的準確性。

For a traditional GPS receiver is used, a user usually needs to download the required navigation message, and it will cost approximate 12.5 minutes for a cold start. Currently, a lot of researches aim to shorten the time-to-first-fix as the goal to achieve fast positioning.
Many studies use GPS satellite position solutions to improve the positioning accuracy. The primary approach of this research is to use the precise ephemeris downloaded from International GNSS Service(IGS) and to use Bernese Software to generate the precise satellite state data. In the process, the batch filter method with position and velocity observations is applied to convert the Bernese data into the precise broadcast ephemeris for traditional GPS receivers. In particular, the velocity observation partial differential with respect to 15 broadcast ephemeris parameters is quite complicate. Therefore, the real precise ephemeris is used to verify the derivation. Different satellite observation combination and sampling rates of precise ephemeris are processed to verify the accuracy of satellite location. The improvement varies from 3 to 20 times in range.
In positioning experiments, different precise broadcast ephemerides are applied in position determination. As shown in the experiment results, with the shorter observation time, the observation with the satellite's velocity enhances the solution accuracy.

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