{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,24]],"date-time":"2026-01-24T07:26:38Z","timestamp":1769239598951,"version":"3.49.0"},"reference-count":45,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2019,1,26]],"date-time":"2019-01-26T00:00:00Z","timestamp":1548460800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41761134092"],"award-info":[{"award-number":["41761134092"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41704024"],"award-info":[{"award-number":["41704024"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100008045","name":"Nanjing University of Information Science and Technology","doi-asserted-by":"publisher","award":["2243141801036"],"award-info":[{"award-number":["2243141801036"]}],"id":[{"id":"10.13039\/501100008045","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100007928","name":"Ningbo Municipal Bureau of Science and Technology","doi-asserted-by":"publisher","award":["2014A35008"],"award-info":[{"award-number":["2014A35008"]}],"id":[{"id":"10.13039\/501100007928","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100011474","name":"Key Laboratory of Precise Engineering and Industry Surveying, National Administration of Surveying, Mapping and Geoinformation","doi-asserted-by":"publisher","award":["PF2017-6"],"award-info":[{"award-number":["PF2017-6"]}],"id":[{"id":"10.13039\/501100011474","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Natural Science Foundation of Zhejiang Province","doi-asserted-by":"publisher","award":["LY16D040001"],"award-info":[{"award-number":["LY16D040001"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The current cycle slip detection methods of Global Navigation Satellite System (GNSS) were mostly proposed on the basis of assuming the ionospheric delay varying smoothly over time. However, these methods can be invalid during active ionospheric periods, e.g., high Kp index value and scintillations, due to the significant increase of the ionospheric delay. In order to detect cycle slips during high ionospheric activities successfully, this paper proposes a method based on two modified Hatch\u2013Melbourne\u2013W\u00fcbbena combinations. The measurement noise in the Hatch\u2013Melbourne\u2013W\u00fcbbena combination is minimized by employing the optimally selected combined signals, while the ionospheric delay is detrended using a smoothing technique. The difference between the time-differenced ambiguity of the combined signal and this estimated ionospheric trend is adopted as the detection value, which can be free from ionospheric effect and hold the high precision of the combined signal. Five threshold determination methods are proposed and compared to decide the cycle slip from the magnitude aspect. This proposed method is tested with triple-frequency Global Navigation Satellite System observations collected under high ionospheric activities. Results show that the proposed method can correctly detect and fix cycle slips under disturbed ionosphere.<\/jats:p>","DOI":"10.3390\/rs11030250","type":"journal-article","created":{"date-parts":[[2019,1,29]],"date-time":"2019-01-29T03:40:55Z","timestamp":1548733255000},"page":"250","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Cycle Slip Detection during High Ionospheric Activities Based on Combined Triple-Frequency GNSS Signals"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7297-8639","authenticated-orcid":false,"given":"Dongsheng","family":"Zhao","sequence":"first","affiliation":[{"name":"School of Remote Sensing &amp; Geomatics Engineering, Nanjing University of Information Science &amp; Technology, Nanjing 210044, China"},{"name":"Department of Civil Engineering, The University of Nottingham Ningbo China, Ningbo 315100, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9692-0439","authenticated-orcid":false,"given":"Craig M.","family":"Hancock","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, The University of Nottingham Ningbo China, Ningbo 315100, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3703-981X","authenticated-orcid":false,"given":"Gethin Wyn","family":"Roberts","sequence":"additional","affiliation":[{"name":"Faculty of Science and Technology, University of the Faroe Islands, 100 T\u00f3rshavn, Faroe Islands"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5108-4828","authenticated-orcid":false,"given":"Shuanggen","family":"Jin","sequence":"additional","affiliation":[{"name":"School of Remote Sensing &amp; Geomatics Engineering, Nanjing University of Information Science &amp; Technology, Nanjing 210044, China"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"871","DOI":"10.1016\/0021-9169(74)90032-4","article-title":"Ionospheric irregularities causing scintillation of GHz frequency radio signals","volume":"36","author":"Wernik","year":"1974","journal-title":"J. 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