顾及文献[16]所建立的全球对流层天顶延迟模型GZTD的时间分辨率为24 h,为进一步提高GZTD模型的时间分辨率,利用GGOS atmosphere的2002—2009年全球天顶对流层延迟格网时间序列按照其6h的时间分辨率分别建模,再采用三次样条插值计算任意时刻的天顶对流层延迟估值,由此构建了一种时间分辨率更高(6h)的改进的GZTD模型(GZTD-6h).经过两种模型内符合检验对比分析表明,GZTD-6h模型内符合精度(bias:0.17 cm,RMS:3.9 cm)优于GZTD(bias:0.17 cm,RMS:4.4 cm).使用全球IGS站进行外符合检验,统计结果表明GZTD-6h模型(bias:-0.22 cm,RMS:4.05 cm)相比GZTD(bias:-0.45 cm,RMS:4.51 cm)改善明显.
The time resolution of GZTD model developed by Yao[16] is 24 hours. To further improve the time resolution of GZTD model, we used the time series of global 4D-grid ZTD from 2002 to 2009, provided by GGOS atmosphere, to construct model according to the 6 hours resolution, and then calculated the ZTD at any time using the cubic spline interpolation method. Thus we developed an improved higher time resolution (6h) GZTD model (GZTD-6h). Analyzing the inner coincidence of two models comparatively, we found that GZTD-6h model (bias: 0.17 cm, RMS: 3.9 cm) performs better than GZTD model (bias: 0.17 cm, RMS: 4.4 cm). Using ZTD time series from global International GNSS Service (IGS) sites to analyze outer coincidence, the statistical results shows that GZTD-6h model (bias:-0.22 cm, RMS: 4.05 cm) improves significantly, compared with GZTD model (bias:-0.45 cm, RMS: 4.51 cm).
[1] YIN Haitao, HUANG Dingfa,XIONG Yongliang, et al. New Model for Tropospheric Delay Estimation of GPS Signal[J]. Geomatics and Information Science of Wuhan University, 2007, 32(5): 454-457. (殷海涛, 黄丁发, 熊永良, 等. GPS信号对流层延迟改正新模型研究[J]. 武汉大学学报:信息科学版, 2007, 32(5): 454-457.)
[2] HOPFIELD H S. Two-quartic Tropospheric Refractivity Profile for Correcting Satellite Data[J]. Journal of Geophysical Research, 1969, 74(18): 4487-4499.
[3] SAASTAMOINEN J. Contributions to the Theory of Atmospheric Refraction[J]. Bulletin Géodésique, 1972, 105(1): 279-298.
[4] BLACK H D. An Easily Implemented Algorithm for the Tropospheric Range Correction[J]. Journal of Geophysical Research: Solid Earth (1978—2012), 1978, 83(B4): 1825-1828.
[5] COLLINS J P, LANGLEY R B. A Tropospheric Delay Model for the User of the Wide Area Augmentation System[M]. Fredericton:Department of Geodesy and Geomatics Engineering, University of New Brunswick, 1996.
[6] COLLINS J P, LANGLEY R B. The Residual Tropospheric Propagation Delay: How Bad Can it Get?[C]//Proceedings of ION GPS-98. 11 International Technical Meeting of the Satellite Division of the Institute of Navigation.Nashville,Tennessee: [s.n.], 1998: 729-738.
[7] COLLINS P, LANGLEY R, LAMANCE J. Limiting Factors In Tropospheric Propagation Delay Error Modelling for GPS Airborne Navigation[C]//Proceedings of the Institute of Navigation 52nd Annual Meeting. Cambridge, MA: [s.n.], 1996: 1-10.
[8] LEANDRO R, SANTOS M C, LANGLEY R B. UNB Neutral Atmosphere Models: Development and Performance[C]//Proceedings of ION NTM. Monterey, California, USA: [s.n.], 2006: 564-573.
[9] LEANDRO R F, LANGLEY R B, SANTOS M C. UNB3m_pack: A Neutral Atmosphere Delay Package for Radiometric Space Techniques[J]. GPS Solutions, 2008, 12(1): 65-70.
[10] DODSON A H, CHEN Wu, BAKER H C, et al. Assessment of EGNOS Tropospheric Correction Model[C]//Proceedings of the 12th International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GPS 1999). Nashville, TN: [s.n.],1999: 1401-1408.
[11] PENNA N, DODSON A, CHEN Wu. Assessment of EGNOS Tropospheric Correction Model[J]. The Journal of Navigation, 2001, 54(1): 37-55.
[12] UENO M, HOSHINOO K, MATSUNAGA K, et al. Assessment of Atmospheric Delay Correction Models for the Japanese MSAS[C]//Proceedings of the 14th International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GPS 2001). Salt Lake City, UT: [s.n.],2001: 2341-2350.
[13] QU Weijing, ZHU Wenyao, SONG Shuli, et al. The Evaluation of Precision about Hopfield, Saastamoinen and EGNOS Tropospheric Delay Correction Model[J]. ActaAstronomica Sinica, 2008, 49(1): 113-122. (曲伟菁, 朱文耀, 宋淑丽, 等. 三种对流层延迟改正模型精度评估[J]. 天文学报, 2008, 49(1): 113-122.)
[14] MOPS W. Minimum Operational Performance Standards for Global Positioning System/wide Area Augmentation System Airborne Equipment[R]. Washington DC: RTCA Inc. Documentation No. RTCA/DO-229B, 1999:6.
[15] LI Wei, YUAN Yunbin, OU Jikun, et al. A New Global Zenith Tropospheric Delay Model IGGtrop for GNSS Applications[J]. Chinese Science Bulletin, 2012, 57(17): 2132-2139. (李薇, 袁运斌, 欧吉坤, 等. 全球对流层天顶延迟模型IGGtrop的建立与分析[J]. 科学通报, 2012, 57(15): 1317-1325.)
[16] YAO Yibin, HE Changyong, ZHANG Bao, et al. A New Global Zenith Tropospheric Delay Model GZTD[J]. Chinese Journal of Geophysics, 2013, 56(7): 2218-2227. (姚宜斌, 何畅勇, 张豹, 等. 一种新的全球对流层天顶延迟模型 GZTD[J]. 地球物理学报, 2013, 56(7): 2218-2227.)
[17] UPPALA S M, KÅLLBERG P W, SIMMONS A J, et al. The ERA-40 Re-analysis[J]. Quarterly Journal of the Royal Meteorological Society, 2005, 131(612): 2961-3012.
[18] BOEHM J, HEINKELMANN R, SCHUH H. Short Note: A Global Model of Pressure and Temperature for Geodetic Applications[J]. Journal of Geodesy, 2007, 81(10): 679-683.
[19] YAO Yibin, ZHU Shuang, YUE Shunqiang. A Globally Applicable, Season-specific Model for Estimating the Weighted Mean Temperature of the Atmosphere[J]. Journal of Geodesy, 2012, 86(12): 1125-1135.
[20] ACKERMAN S A, KNOX J A. Meteorology: Understanding the Atmosphere[M].Pacific Grove, CA: Brooks/Cole-Thomson Learning,2002.
