星历表时间

Ephemeris:a table giving the coordinates of a celestial body at a number of specific times during a given period.

星历表：一张给出一定时期内一个天体在一些特定时间的坐标的表。

A set of new formulas for computing the position and time of crossover points is presented.

本文给出了一组新的计算交叉点位置和时间的公式，这组公式利用测高卫星精密重复轨道的特点，不需要从星历表中读取每个弧段在赤道上的位置及穿越赤道的时间。

If you look up your Heliocentric Ephemeris you will find that "in the latter part of February 1929" there was a conjunction in Cancer!

假如你查阅以太阳为中心的星历表你就会发现在1929年2月的后段时间，出现了一个在巨蟹座的重合！

In this study, six campaigns around Anping tide gauge, Tainan, were successfully performed and the collected GPS buoy data were processed with four types of precise ephemeris provided by IGS, including final product, rapid product, ultra-rapid product and ultra-rapid product with the use of PPP technique. Comparing the PPP results with DGPS, the differences reach 3~5 cm in the horizontal and 10 cm in the vertical with final product; 6~8 cm in the horizontal and 15 cm in the vertical with rapid product; 15~20 cm in the horizontal and 30~40 cm in the vertical with ultra-rapid product; 2~3 m in the horizontal and 3~4 m in the vertical with ultra-rapid product. In addition, the collected data were also processed by DGPS techniques using different reference stations to analyze the effect of various baselines. The results show that accuracy degrades when the baselines increase.

本研究在台南安平潮位站旁进行6次GPS浮标施测，首先利用与GPS浮标距离不同之GPS参考主站来进行差分定位，分析基线距离对GPS浮标定位成果的影响，由实验结果可得出基线越长则定位准确度越低；再以IGS提供之最终产品、快速产品、超快速产品(Ultra-Rapid product)之观测部分observed half、超快速产品(Ultra-Rapid product)之预估部分四种不同发布延迟时间的精密星历与精密时表改正资料对GPS浮标进行精密单点定位解算，与传统差分相对定位方法定位结果进行比较后，得出使用最终产品之平面方向均方根误差(Root Mean Square Error， RMSE)可达3~5公分，而高程方向均方根误差可达10公分；快速产品之平面方向均方根误差可达6~8公分，而高程方向均方根误差可达15公分；超快速产品观测部分之平面方向均方根误差可达15~20公分，而高程方向均方根误差可达30~40公分；超快速产品预估部分之平面方向均方根误差可达2~3公尺，而高程方向均方根误差可达3~4公尺。

Furthermore, they continuously transmit radio signals of low power and ultra high frequency. They are also equipped with atomic clocks. When GPS receivers intend to calculate its GPS position on the earth, they will receive the signals from satellites, calculate transmission time with a pre-stored ephemeri, and then calculate the distances between themselves and at least four GPS satellites with the method of trilateration.

所有的卫星架有原子钟，当GPS接收器要找出自己目前在地球表面上的位置时，会接收各卫星的讯号，并依储存的星历表计算传送时间，再利用三边测量法订出自己与至少四颗GPS卫星之间的精确距离，即可算出所在位置。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失