{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T14:26:28Z","timestamp":1775744788684,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2023,2,8]],"date-time":"2023-02-08T00:00:00Z","timestamp":1675814400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key R&amp;D Program of China","doi-asserted-by":"publisher","award":["2021YFA0716603"],"award-info":[{"award-number":["2021YFA0716603"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Tracking ambiguity and multipath are two serious threats in processing binary offset carrier (BOC) signals that are widely used in global navigation satellite systems (GNSS). Three-loop tracking methods, such as dual binary phase-shift keying tracking (DBT), use a delay lock loop (DLL), a phase lock loop (PLL), and a subcarrier PLL (SPLL) to track the code, carrier, and subcarrier, respectively, thus solving the tracking ambiguity problem. However, the multipath remains an important factor in the ranging performance deterioration of these tracking methods. Using the offset correlator (OC) technique in the SPLL can effectively mitigate subcarrier multipath errors, but it substantially raises thermal noise errors. To solve this contradiction, this paper proposes a prompt-assisted-offset correlator (PAOC) technique that combines the prompt and offset correlators in a complementary way to mitigate multipath for BOC signals. Compared with the original OC technique, the PAOC technique has less thermal noise performance loss. Moreover, this paper discovers and quantifies the interaction between carrier and subcarrier multipath errors by analyzing the coupling effect between SPLL and PLL. Most multipath mitigation methods for BOC signals ignore the carrier multipath in the PLL, so their subcarrier multipath performance is not optimal. Thus, this paper further proposes applying the PAOC technique in both PLL and SPLL to mitigate carrier and subcarrier multipath errors simultaneously. Theoretical analysis and experimental results demonstrate that the proposed method can significantly improve the multipath performance with small noise performance loss.<\/jats:p>","DOI":"10.3390\/rs15040937","type":"journal-article","created":{"date-parts":[[2023,2,9]],"date-time":"2023-02-09T02:55:54Z","timestamp":1675911354000},"page":"937","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Multipath Mitigation for BOC Signals Based on Prompt-Assisted-Offset Correlator"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6034-1702","authenticated-orcid":false,"given":"Zhenyu","family":"Tian","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, Tsinghua University, Beijing 100084, China"},{"name":"Beijing National Research Center for Information Science and Technology, Beijing 100084, China"}]},{"given":"Xiaowei","family":"Cui","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Tsinghua University, Beijing 100084, China"},{"name":"Beijing National Research Center for Information Science and Technology, Beijing 100084, China"}]},{"given":"Mingquan","family":"Lu","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Tsinghua University, Beijing 100084, China"},{"name":"Beijing National Research Center for Information Science and Technology, Beijing 100084, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,8]]},"reference":[{"key":"ref_1","unstructured":"Kaplan, E.D., and Hegarty, C. (2017). Understanding GPS\/GNSS: Principles and Applications, Artech House."},{"key":"ref_2","unstructured":"Pullen, S., Enge, P., and Lee, J. (2013, January 28\u201330). Local-area differential GNSS architectures optimized to support unmanned aerial vehicles (UAVs). Proceedings of the International Technical Meeting of the Institute of Navigation (ION ITM 2013), San Diego, CA, USA."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1002\/j.2161-4296.2008.tb00415.x","article-title":"The MBOC modulation: The final touch to the Galileo frequency and signal plan","volume":"55","author":"Hein","year":"2008","journal-title":"Navigation"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1186\/s43020-020-00023-x","article-title":"Status, perspectives and trends of satellite navigation","volume":"1","author":"Hein","year":"2020","journal-title":"Satell. Navig."},{"key":"ref_5","unstructured":"Betz, J.W. (1999, January 25\u201327). The offset carrier modulation for GPS modernization. Proceedings of the 1999 National Technical Meeting of The Institute of Navigation, San Diego, CA, USA."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1002\/j.2161-4296.2001.tb00247.x","article-title":"Binary Offset Carrier Modulations for Radionavigation","volume":"48","author":"Betz","year":"2001","journal-title":"Navigation"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"877","DOI":"10.1049\/el:20071101","article-title":"Dual estimate receiver of binary offset carrier modulated signals for global navigation satellite systems","volume":"43","author":"Hodgart","year":"2007","journal-title":"Electron. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"729","DOI":"10.1049\/iet-rsn.2013.0306","article-title":"Double phase estimator: New unambiguous binary offset carrier tracking algorithm","volume":"8","author":"Borio","year":"2014","journal-title":"IET Radar Sonar Navig."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1049\/iet-rsn.2014.0349","article-title":"Dual binary phase-shift keying tracking method for Galileo E5 AltBOC(15,10) signal and its thermal noise performance","volume":"9","author":"Zhu","year":"2015","journal-title":"IET Radar Sonar Navig."},{"key":"ref_10","unstructured":"Zhu, Y., Cui, X., and Lu, M. (2015, January 14\u201318). A unified tracking structure for both single-band and dual-band processing of high-order BOC signal. Proceedings of the 28th International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GNSS+ 2015), Tampa, FL, USA."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1588","DOI":"10.1049\/iet-rsn.2018.5587","article-title":"GNSS multipath estimation and mitigation based on particle filter","volume":"13","author":"Qin","year":"2019","journal-title":"IET Radar Sonar Navig."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"502","DOI":"10.1002\/j.2161-4296.1995.tb01903.x","article-title":"Performance evaluation of the multipath estimating delay lock loop","volume":"42","author":"Townsend","year":"1995","journal-title":"Navigation"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1002\/j.2161-4296.1992.tb02276.x","article-title":"Theory and performance of narrow correlator spacing in a GPS receiver","volume":"39","author":"Fenton","year":"1992","journal-title":"Navigation"},{"key":"ref_14","unstructured":"McGraw, G.A., and Braasch, M.S. (1999, January 25\u201327). GNSS multipath mitigation using gated and high resolution correlator concepts. Proceedings of the 1999 National Technical Meeting of the Institute of Navigation, San Diego, CA, USA."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1007\/PL00000035","article-title":"The mitigation of multipath errors by strobe correlators in GPS\/GLONASS receivers","volume":"2","author":"Veitsel","year":"1998","journal-title":"GPS Solut."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"951","DOI":"10.1109\/TAES.2007.4383585","article-title":"Gating functions for multipath mitigation in GNSS BOC signals","volume":"43","author":"Nunes","year":"2007","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1136","DOI":"10.1109\/TAES.2011.5751248","article-title":"\u201cBOC-Gated-PRN\u201d A Multipath Mitigation Technique for BOC (n, n) Waveforms","volume":"47","author":"Wu","year":"2011","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_18","unstructured":"Irsigler, M., and Eissfeller, B. (2003, January 9\u201312). Comparison of multipath mitigation techniques with consideration of future signal structures. Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS\/GNSS 2003), Portland, OR, USA."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Jovanovic, A., Tawk, Y., Botteron, C., and Farine, P.A. (2010, January 4\u20136). Multipath mitigation techniques for CBOC, TMBOC and AltBOC signals using advanced correlators architectures. Proceedings of the IEEE\/ION Position, Location and Navigation Symposium, Indian Wells, CA, USA.","DOI":"10.1109\/PLANS.2010.5507231"},{"key":"ref_20","unstructured":"Hodgart, M., Blunt, P., and Unwin, M. (2007, January 25\u201328). The optimal dual estimate solution for robust tracking of binary offset carrier (BOC) modulation. Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007), Fort Worth, TX, USA."},{"key":"ref_21","unstructured":"Gao, Y., Yao, Z., Zhu, Y., and Lu, M. (2014, January 27\u201329). A two-dimension tracking based multipath mitigation method for BOC signals. Proceedings of the 2014 International Technical Meeting of The Institute of Navigation, San Diego, CA, USA."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"4824","DOI":"10.1109\/TAES.2022.3163237","article-title":"Multipath Mitigation Methods of BOC-family Signals Based on Dual BPSK Tracking Techniques","volume":"58","author":"Wang","year":"2022","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1002\/sat.1180","article-title":"Strobe double phase estimator: A multipath mitigating technique for BOC signal in GNSS based on double phase estimator","volume":"35","author":"Chengtao","year":"2017","journal-title":"Int. J. Satell. Commun. Netw."},{"key":"ref_24","unstructured":"B\u00e9taille, D., Maenpa, J., Euler, H.J., and Cross, P. (2003, January 22\u201324). A new approach to GPS phase multipath mitigation. Proceedings of the 2003 National Technical Meeting of The Institute of Navigation, Anaheim, CA, USA."},{"key":"ref_25","unstructured":"B\u00e9taille, D., Maenpa, J., Euler, H.J., and Cross, P. (2003, January 9\u201312). Overcoming the limitations of the phase multipath mitigation window. Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS\/GNSS 2003), Portland, OR, USA."},{"key":"ref_26","unstructured":"European Commission, Directorate-General for Internal Market, Industry, Entrepreneurship and SMEs (2021). European GNSS (Galileo) Open Service Signal in Space Interface Control Document, Office for Official Publications of the European Communities."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1007\/s10291-003-0043-9","article-title":"Characterization of the effects of high multipath phase rates in GPS","volume":"7","author":"Kelly","year":"2003","journal-title":"GPS Solut."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Wang, Y., Chen, X., and Liu, P. (2018). Statistical multipath model based on experimental GNSS data in static urban canyon environment. Sensors, 18.","DOI":"10.3390\/s18041149"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1034","DOI":"10.1016\/j.asr.2018.06.005","article-title":"Statistical multipath model comparative analysis of different GNSS orbits in static urban canyon environment","volume":"62","author":"Chen","year":"2018","journal-title":"Adv. Space Res."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1007\/s10291-009-0155-y","article-title":"Characterization of multipath phase rates in different multipath environments","volume":"14","author":"Irsigler","year":"2010","journal-title":"GPS Solut."},{"key":"ref_31","first-page":"366","article-title":"Measuring GNSS multipath distributions in urban canyon environments","volume":"64","author":"Xie","year":"2014","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_32","unstructured":"Irsigler, M., Avila-Rodriguez, J.A., and Hein, G.W. (2005, January 13\u201316). Criteria for GNSS multipath performance assessment. Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, USA."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1538","DOI":"10.1109\/TAES.2009.5310316","article-title":"Generalized Theory of Code Tracking with an Early-Late Discriminator Part I: Lower Bound and Coherent Processing","volume":"45","author":"Betz","year":"2009","journal-title":"IEEE Trans. Aerosp. Electron. 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