caa a22 4500 606162089 CHVBK 20210128100637.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s10291-014-0372-x doi (NATIONALLICENCE)springer-10.1007/s10291-014-0372-x Assessing and mitigating the effects of the ionospheric variability on DGPS [Elektronische Daten] [Duojie Weng, Shengyue Ji, Wu Chen, Zhihua Li, Ying Xu, Lei Ye] The differential GPS (DGPS) performance can be affected by the ionospheric variability, especially in low-latitude areas. We evaluated the behavior of the ionospheric variability in low-latitude areas in the 11-year cycle of the solar activity. During periods of solar maximum, the percentage of the daily maximum gradient that exceeds 50mm/km has reached 73% in 2001. Assuming that the baseline length is 20km, the gradient larger than 50mm/km can lead to more than 1.0-m ranging error, which is significant if we want to achieve meter-level accuracy with DGPS. An ionospheric gradient model built from a number of reference stations is proposed for estimating the differential ionospheric delays. The effectiveness of the model is demonstrated under both the quiet and active ionospheric conditions in low-latitude areas. For a short baseline length of 16.9km in Hong Kong, the horizontal positioning accuracy can be improved by 41 and 61% during active solar years and geomagnetic storms, respectively. The improvements show that the model is capable of reducing the spatial decorrelation caused by the ionospheric variability, and the model can be used in DGPS especially over the regions, such as low-latitude areas, where the large ionospheric variability happens frequently. Springer-Verlag Berlin Heidelberg, 2014 DGPS nationallicence Spatial decorrelation nationallicence Ionospheric gradient model nationallicence Low-latitude areas nationallicence Weng Duojie Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Jiulong, Hong Kong aut Ji Shengyue China University of Petroleum, Qingdao, China aut Chen Wu Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Jiulong, Hong Kong aut Li Zhihua College of Energy and Electrical Engineering, Hohai University, Nanjing, China aut Xu Ying Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Jiulong, Hong Kong aut Ye Lei Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Jiulong, Hong Kong aut GPS Solutions Springer Berlin Heidelberg 19/1(2015-01-01), 107-116 1080-5370 19:1<107 2015 19 10291 https://doi.org/10.1007/s10291-014-0372-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10291-014-0372-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Weng Duojie Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Jiulong, Hong Kong aut NATIONALLICENCE 700 1- Ji Shengyue China University of Petroleum, Qingdao, China aut NATIONALLICENCE 700 1- Chen Wu Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Jiulong, Hong Kong aut NATIONALLICENCE 700 1- Li Zhihua College of Energy and Electrical Engineering, Hohai University, Nanjing, China aut NATIONALLICENCE 700 1- Xu Ying Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Jiulong, Hong Kong aut NATIONALLICENCE 700 1- Ye Lei Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Jiulong, Hong Kong aut NATIONALLICENCE 773 0- GPS Solutions Springer Berlin Heidelberg 19/1(2015-01-01), 107-116 1080-5370 19:1<107 2015 19 10291