Real-time Estimation Method for Tropospheric Scatter Slant Delay at Low Elevation
WU Wenyi①② CHEN Xihong① LIU Shaowei①
①(Air and Missile Defense College, Air Force Engineering University, Xi’an 710051, China) ②(Northwest Institute of Nuclear Technology, Xi’an 710024, China)
Based on ray tracing, a real-time method of tropospheric scatter slant delay estimation is proposed to estimate the low-elevation tropospheric delay in the absence of meteorological data. The model uses the UNB3m model to obtain atmospheric meteorological parameters, establishes the tropospheric atmospheric refractive index profile model, and overcomes the limitation of meteorological data on the refractive index calculation in the ray tracing method. The atmospheric refractive index profile of the troposphere is calculated by using the meteorological data of the International GNSS Service (IGS) stations in Asia in 2012, and the accuracy of the tropospheric delay model is verified to be less than 25 mm. The three stations with the baseline distance are selected and divided into three sets of scatter correspondence comparison stations. The oblique delay at 0°--5° incident angle is calculated by ray tracing method. The results show that the maximum one-way propagation delay is 22.38--48.37 m for the three groups, and 3.73--8.07 ns for the two-way time offset 95%.
XU Songyi, CHEN Changjia, and LI Wenduo. A prediction method of the troposcatter transmission loss with high elevation[J]. Chinese Journal of Radio Science, 2011, 26(3): 528-531. doi: 10.13443/j.cjors.2011.03.002.
LIU Qiang, SUN Jizhe, CHEN Xihong, et al. Analysis of two way troposphere time transfer and its delay errors[J]. Acta Geodaetica et Cartographica Sinica, 2014, 43(4): 341-347. doi: 10.13485/j.cnki.11-2089.2014.0051.
CHEN Xihong, LIU Zan, LIU Qiang, et al. Tropospheric slant delay estimation in two- way troposphere time transfer[J]. Journal of National University of Defende Technology, 2016, 38(2): 171-176. doi: 10.11887/j.cn.201602028.
ZHANG Lijun, ZHANG Rui, and ZHAO Zhenwei. Analysis of rotational loss in troposcatter propagation[J]. Journal of Electionics & Information Technology, 2015, 37(6): 1502-1506. doi: 10.11999/JEIT141233.
[7]
CHEN Xihong, LIU Qiang, Hu Denghu, et al. Delay analysis of two way time transfer based on troposphere gradients[C]. The 10th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM 2014), Beijing, China, 2014: 543-547.
LIU Qiang, CHEN Xihong, XUE Lunsheng, et al. Slant propagation delay snalysis in two way troposphere transfer based on mapping function[J]. Journal of University of Electronic Science and Technology of China, 2015, 44(5): 689-694. doi: 10.3969/j.issn.1001-0548.2015.05.009.
GUO Jiming, ZHANG Di, SHI Junbo, et al. Using ray-tracing to analyse the precision of three classical tropospheric mapping functions in china[J]. Geomatics and Information Science of Wuhan University, 2015, 40(2): 182-187. doi: 10. 13203/j.whugis20130096.
CHEN Xihong, LIU Zan, LIU Jiye, et al. Estimating tropospheric slant scatter delay at low elevation[J]. Journal of Electionics & Information Technology, 2016, 38(2): 408-412. doi: 10.11999/JEIT150628.
[11]
LEANDRO R, LANGLY R B, and SANTO M. UNB3m_ pack: A neutral atmosphere delay package for radiometric space techniques[J]. GPS Solutions, 2008, 12(1): 65-70. doi: 10.1007/s10291-007-0077-5.
[12]
SAKIDIN H. Nonhydrostatics UNBab mapping function simplification for tropospheric delay[J]. Procedia Engineering, 2013, 53(12): 710-714. doi: 10.1016/j.proeng.2013.02.093.
ZHAO Jingyang, SONG Shuli, CHEN Qinming, et al. Establishment of a new global model for zenith troposphere delay based on functional expression for its vertical profile[J]. Chinese Journal of Geophysics, 2014, 57(10): 3140-3153. doi: 10.6038/cjg20141005.
[14]
DAVID E, MACMILLAN D S, and JOHN M G. Tropospheric delay ray tracing applied in VLBI analysis[J]. Journal of Geophysical Research: Solid Earth, 2014, 119(12): 9156-9170. doi: 10.1002/2014JB011552.
[15]
JOHANNES B, GREGOR M, MICHAEL S, et al. Development of an improved empirical model for slant delays in the troposphere (GPT2w)[J]. GPS Solutions, 2015, 19(3): 433-441. doi: 10.1007/s10291-014-0403-7.
YAO Yibin, CAO Na, XU Chaoqian, et al. Accuracy assessment and analysis for GPT2[J]. Acta Geodaetica et Cartographica Sinica, 2015, 44(7): 726-733. doi: 10.11947/j. AGCS.2015.20140356.
YAO Yibin, ZHANG Bao, YAN Feng, et al. Two new sophisticated models for tropospheric delay corrections[J]. Chinese Journal of Geophysics, 2015, 58(5): 1492-1501. doi: 10.6038/cjg20150503.
[18]
Qu W J, Zhu W Y, Song S L, et al. Evaluation of the precision of three tropospheric delay correction models[J]. Chinese Astronomy and Astrophysics, 2008, 32(4): 429-438. doi: 10.1016/j.chinastron.2008.10.010.
SUN Fang, WANG Hongguang, KANG Shifeng, et al. A ray tracing algorithm for duct environment[J]. Chinese Journal of Radio Science, 2008, 23(1): 179-183. doi: 10.13443/j.cjors. 2008.01.019.
[20]
REZA G F, PETER D, and RICHAID B. A web-based package for ray tracing the netural atmosphere radiomeric path delay[J]. Computer and Geosciences, 2008, 35(6): 1113-1124. doi: 10.1016/j.cageo.2008.02.027.
[21]
LANDON U, FELIPE G N, and MARCELO C S. Ray-traced slant factors for mitigating the tropospheric delay at the observation level[J]. Journal of Geodesy, 2012, 86(2): 149-160. doi: 10.1007/s00190-011-0503-x.
