Various methods for precise orbit determination (POD) of low earth orbiters (LEO) are briefly intro-duced in this paper. Based on the software named SHORD-Ⅲ developed by our institute,sin-gle-difference (SD) and zero...Various methods for precise orbit determination (POD) of low earth orbiters (LEO) are briefly intro-duced in this paper. Based on the software named SHORD-Ⅲ developed by our institute,sin-gle-difference (SD) and zero-difference (ZD) dynamic POD based on LEO carrying an on-board GPS receiver is mainly discussed. The approaches are tested using real GRACE data (November 5―25,2002) and independently validated with Satellite Laser Ranging (SLR) measurements over the same 21 days. Comparisons with the scientific orbits provided by GFZ indicate that the SD POD RMS accuracy can achieve 5,10 and 6 cm in radial,along and cross the track,and the ZD POD RMS accuracy can achieve 4,8 and 4 cm in radial,along and cross the track. SLR validation shows that SD POD accuracy is better than 8 cm in distance,and ZD POD accuracy is better than 6 cm.展开更多
The joint US/French Jason-1 satellite altimeter mission, launched from the Vandenberg Air Force Base on December 7, 2001, continues the time series of centimeter-level ocean topography observations as the follow-on to...The joint US/French Jason-1 satellite altimeter mission, launched from the Vandenberg Air Force Base on December 7, 2001, continues the time series of centimeter-level ocean topography observations as the follow-on to the highly successful T/P radar altimeter satellite. Orbit error especially the radial orbit error is a major component in the overall budget of all altimeter satellite missions, in order to continue the T/P standard of observations. Jason-1 has a radial orbit error budget requirement of 2.5 cm. In this work, two cycles (December 19, 2002 to January 7, 2003) of the Jason-1 on-board GPS data were processed using the zero-difference (ZD) dynamic precise orbit determination (POD) technique. The resulting Jason-1 orbit accuracy was assessed by comparison with the precise orbit ephemeris (POE) produced by JPL, orbit overlaps and SLR residuals. These evaluations indicate that the RMS radial accuracy is in the range of 1-2 cm.展开更多
文摘目的分析湖北省十堰市中心血站血型血清学室间质量评价(external quality assessment,EQA)结果,及时发现问题并制订相应改进措施,提高血型血清学检测及分析能力。方法整理2016—2022年13次EQA回执报告,结合《年度室间质评(EQA)总结报告》,收集各检测项目与参考答案不符合产生的原因。结果ABO正、反定型符合率为100%(78/78);RhD血型鉴定符合率87.2%(34/39);直接抗人球蛋白试验符合率为100%(39/39);抗体筛选和鉴定符合率为87.2%(68/78);交叉配血符合率为97.4%(114/117)。血型血清学EQA整体符合率为94.9%(333/351),结果满意12次,有待改进1次,其中10次Z值为0,“20N2”Z值为0.2、“21N2”Z值为0.7,“22N1”Z值为2.5,2020—2022年Z值有上升趋势。结论世界卫生组织(World Health Organization,WHO)中国地区血型血清学EQA活动检测难度系数逐年提高,检测人员只有不断加强血型血清学检测理论学习,掌握新技术、新方法并结合运用,才能对日常工作中临床疑难结果做出准确判断,为患者提供科学、合理、安全、有效的血液输注。
文摘Various methods for precise orbit determination (POD) of low earth orbiters (LEO) are briefly intro-duced in this paper. Based on the software named SHORD-Ⅲ developed by our institute,sin-gle-difference (SD) and zero-difference (ZD) dynamic POD based on LEO carrying an on-board GPS receiver is mainly discussed. The approaches are tested using real GRACE data (November 5―25,2002) and independently validated with Satellite Laser Ranging (SLR) measurements over the same 21 days. Comparisons with the scientific orbits provided by GFZ indicate that the SD POD RMS accuracy can achieve 5,10 and 6 cm in radial,along and cross the track,and the ZD POD RMS accuracy can achieve 4,8 and 4 cm in radial,along and cross the track. SLR validation shows that SD POD accuracy is better than 8 cm in distance,and ZD POD accuracy is better than 6 cm.
基金Supported by the National Natural Science Foundation of China (Grant No. 40274006)High-tech Research and Development Program of China (Grant No. 2006AA12A107)Science & Technology Commission of Shanghai Municipality (Grant No. 06DZ22101)
文摘The joint US/French Jason-1 satellite altimeter mission, launched from the Vandenberg Air Force Base on December 7, 2001, continues the time series of centimeter-level ocean topography observations as the follow-on to the highly successful T/P radar altimeter satellite. Orbit error especially the radial orbit error is a major component in the overall budget of all altimeter satellite missions, in order to continue the T/P standard of observations. Jason-1 has a radial orbit error budget requirement of 2.5 cm. In this work, two cycles (December 19, 2002 to January 7, 2003) of the Jason-1 on-board GPS data were processed using the zero-difference (ZD) dynamic precise orbit determination (POD) technique. The resulting Jason-1 orbit accuracy was assessed by comparison with the precise orbit ephemeris (POE) produced by JPL, orbit overlaps and SLR residuals. These evaluations indicate that the RMS radial accuracy is in the range of 1-2 cm.
