{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T06:23:51Z","timestamp":1771482231206,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2021,10,4]],"date-time":"2021-10-04T00:00:00Z","timestamp":1633305600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006769","name":"Russian Science Foundation","doi-asserted-by":"publisher","award":["17-77-20005"],"award-info":[{"award-number":["17-77-20005"]}],"id":[{"id":"10.13039\/501100006769","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002261","name":"Russian Foundation for Basic Research","doi-asserted-by":"publisher","award":["19-05-00941"],"award-info":[{"award-number":["19-05-00941"]}],"id":[{"id":"10.13039\/501100002261","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Global navigation satellite system signals are known to be an efficient tool to monitor the Earth ionosphere. We suggest Galileo E5 AltBOC phase and pseudorange observables\u2014a single-frequency combination\u2014to estimate the ionospheric total electron content (TEC). We performed a one-month campaign in September 2020 to compare the noise level for different TEC estimations based on single-frequency and dual-frequency data. Unlike GPS, GLONASS, or Galileo E5a and E5b single-frequency TEC estimations (involving signals with binary and quadrature phase-shift keying, such as BPSK and QPSK, or binary offset carrier (BOC) modulation), an extra wideband Galileo E5 AltBOC signal provided the smallest noise level, comparable to that of dual-frequency GPS. For elevation higher than 60 degrees, the 100 s root-mean-square (RMS) of TEC, an estimated TEC noise proxy, was as follows for different signals: ~0.05 TECU for Galileo E5 AltBOC, 0.09 TECU for GPS L5, ~0.1TECU for Galileo E5a\/E5b BPSK, and 0.85 TECU for Galileo E1 CBOC. Dual-frequency phase combinations provided RMS values of 0.03 TECU for Galileo E1\/E5, 0.03 and 0.07 TECU for GPS L1\/L2 and L1\/L5. At low elevations, E5 AltBOC provided at least twice less single-frequency TEC noise as compared with data obtained from E5a or E5b. The short dataset of our study could limit the obtained estimates; however, we expect that the AltBOC single-frequency TEC will still surpass the BPSK analogue in noise parameters when the solar cycle evolves and geomagnetic activity increases. Therefore, AltBOC signals could advance geoscience.<\/jats:p>","DOI":"10.3390\/rs13193973","type":"journal-article","created":{"date-parts":[[2021,10,8]],"date-time":"2021-10-08T21:26:20Z","timestamp":1633728380000},"page":"3973","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Galileo E5 AltBOC Signals: Application for Single-Frequency Total Electron Content Estimations"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0190-2140","authenticated-orcid":false,"given":"Artem M.","family":"Padokhin","sequence":"first","affiliation":[{"name":"Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia"},{"name":"Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation RAS, 108840 Troitsk, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anna A.","family":"Mylnikova","sequence":"additional","affiliation":[{"name":"Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia"},{"name":"Department of Near-Earth Space Physics, Institute of Solar-Terrestrial Physics SB RAS, 664033 Irkutsk, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3098-224X","authenticated-orcid":false,"given":"Yury V.","family":"Yasyukevich","sequence":"additional","affiliation":[{"name":"Department of Near-Earth Space Physics, Institute of Solar-Terrestrial Physics SB RAS, 664033 Irkutsk, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yury V.","family":"Morozov","sequence":"additional","affiliation":[{"name":"Trapeznikov Institute of Control Sciences RAS, 117997 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gregory A.","family":"Kurbatov","sequence":"additional","affiliation":[{"name":"Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Artem M.","family":"Vesnin","sequence":"additional","affiliation":[{"name":"Department of Near-Earth Space Physics, Institute of Solar-Terrestrial Physics SB RAS, 664033 Irkutsk, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1007\/BF00241558","article-title":"Recent progress in satellite radio beacon studies with particular emphasis on the ATS-6 radio beacon experiment","volume":"25","author":"Davies","year":"1980","journal-title":"Space Sci. 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