{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,23]],"date-time":"2026-01-23T23:27:05Z","timestamp":1769210825764,"version":"3.49.0"},"reference-count":34,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2020,4,19]],"date-time":"2020-04-19T00:00:00Z","timestamp":1587254400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["11803040"],"award-info":[{"award-number":["11803040"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"CAS \u201cYouth Innovative Talent Project\u201d","award":["Y917SC1"],"award-info":[{"award-number":["Y917SC1"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The Loran-C system is an internationally standardized positioning, navigation, and timing service system. It is the most important backup and supplement for the global navigation satellite system (GNSS). However, the existing Loran-C signal acquisition methods are easily affected by noise and cross-rate interference (CRI). Therefore, this article proposes an envelope delay correlation acquisition method that, when combined with linear digital averaging (LDA) technology, can effectively suppress noise and CRI. The selection of key parameters and the performance of the acquisition method are analyzed through a simulation. When the signal-to-noise ratio (SNR) is \u221216 dB, the acquisition probability is more than 90% and the acquisition error is less than 1 \u03bcs. When the signal-to-interference ratio (SIR) of the CRI is \u22125 dB, the CRI can also be suppressed and the acquisition error is less than 5 \u03bcs. These results show that our acquisition method is accurate. The performance of the method is also verified by actual signals emitted by a Loran-C system. These test results show that our method can reliably detect Loran-C pulse group signals over distances up to 1500 km, even at low SNR. This will enable the modern Loran-C system to be a more reliable backup for the GNSS system.<\/jats:p>","DOI":"10.3390\/s20082329","type":"journal-article","created":{"date-parts":[[2020,4,21]],"date-time":"2020-04-21T04:49:38Z","timestamp":1587444578000},"page":"2329","update-policy":"https:\/\/2.zoppoz.workers.dev:443\/https\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Precise Loran-C Signal Acquisition Based on Envelope Delay Correlation Method"],"prefix":"10.3390","volume":"20","author":[{"given":"Wenhe","family":"Yan","sequence":"first","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}]},{"given":"Kunjuan","family":"Zhao","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}]},{"given":"Shifeng","family":"Li","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}]},{"given":"Xinghui","family":"Wang","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}]},{"given":"Yu","family":"Hua","sequence":"additional","affiliation":[{"name":"National Time Service Center, Chinese Academy of Sciences, Xi\u2019an 710600, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences, Xi\u2019an 710600, China"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"11369","DOI":"10.3390\/s101211369","article-title":"Reliable Location-Based Services from Radio Navigation Systems","volume":"10","author":"Qiu","year":"2010","journal-title":"Sensors"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1017\/S0373463312000410","article-title":"Suitability of Low-Frequency Navigation Systems for Artillery Positioning in a GNSS Denied Environment","volume":"66","author":"Griffioen","year":"2013","journal-title":"J. Navig."},{"key":"ref_3","unstructured":"(2020, February 12). Strategy for the Department of Defense Positioning, Navigation and Timing (PNT) enterprise\u2014Ensuring a US Military PNT Advantage. Available online: https:\/\/2.zoppoz.workers.dev:443\/https\/rntfnd.org\/wp-content\/uploads\/DoD-PNT-Strategy.pdf."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1719","DOI":"10.1109\/LAWP.2019.2926734","article-title":"Experimental Study on a Modified Method for Propagation Delay of Long Wave Signal","volume":"18","author":"Li","year":"2019","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Wang, X.Y., Zhang, S.F., and Sun, X.W. (2017). The Additional Secondary Phase Correction System for AIS Signals. Sensors, 17.","DOI":"10.3390\/s17040736"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"473","DOI":"10.1017\/S0373463308004748","article-title":"e-Navigation and the case for eLoran","volume":"61","author":"Williams","year":"2008","journal-title":"J. Navig."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Kim, H., Lee, J., Oh, S.H., So, H., and Hwang, D.H. (2019). Multi-Radio Integrated Navigation System M&S Software Design for GNSS Backup under Navigation Warfare. Electronics, 8.","DOI":"10.3390\/electronics8020188"},{"key":"ref_8","unstructured":"Johnson, G., Wiggins, M., Swaszek, P.F., Hartshorn, L., and Hartnett, R. (2006, January 24\u201327). Possible optimizations for the US Loran system. Proceedings of the 2006 IEEE\/ION Position, Location and Navigation Symposium, Coronado, CA, USA."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1002\/navi.197","article-title":"Providing a Resilient Timing and UTC Service Using eLoran in the United States","volume":"64","author":"Offermans","year":"2017","journal-title":"Navig. J. Inst. Navig."},{"key":"ref_10","unstructured":"(2020, February 15). S.140-Frank LoBiondo Coast Guard Authorization Act of 2018, Available online: https:\/\/2.zoppoz.workers.dev:443\/https\/www.congress.gov\/bill\/115th-congress\/senate-bill\/140."},{"key":"ref_11","first-page":"74","article-title":"Research Status and Progress on the Enhance Loran-C Navigation Technology","volume":"1","author":"Hu","year":"2016","journal-title":"GNSS World Chin."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"101","DOI":"10.11003\/JKGS.2013.2.2.101","article-title":"eLoran Signal Strength and Atmospheric Noise Simulation over Korea","volume":"2","author":"Joon","year":"2013","journal-title":"J. Position. Navig. Timing"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Gao, Y.Y., Hua, Y., Li, S.F., and Yang, C.Z. (2015, January 19\u201322). Acquisition method of Loran-C signal based on matched filter. Proceedings of the 2015 IEEE International Conference on Signal Processing, Communications and Computing, Ningbo, China.","DOI":"10.1109\/ICSPCC.2015.7338868"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1109\/7.826332","article-title":"Loran-C cycle identification in hard-limiting receivers","volume":"36","author":"Fisher","year":"2000","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1109\/TAES.1978.308690","article-title":"Hard Limiting and Sequential Detection Applied to Loran-C","volume":"14","author":"Vanderwal","year":"1978","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2175","DOI":"10.3724\/SP.J.1146.2012.01660","article-title":"Loran-C Signal Fast Acquisition Method and Its performance Analysis","volume":"35","author":"Li","year":"2013","journal-title":"J. Electron. Inf. Technol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1751","DOI":"10.4028\/www.scientific.net\/AMM.241-244.1751","article-title":"Study on Auto-Search Algorithm Based on Subsection Correlation for Loran-C","volume":"241\u2013244","author":"Zhu","year":"2012","journal-title":"Appl. Mech. Mater."},{"key":"ref_18","unstructured":"U.S. Coast Guard and the U.S. Coast Guard Auxiliary (2020, January 30). Loran-C User Handbook. Available online: https:\/\/2.zoppoz.workers.dev:443\/https\/www.loran.org\/otherarchives\/-1992%20-Loran-C%20User%20Handbook%20-%20USCG.pdf."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1109\/MAES.2007.4350283","article-title":"Loran data modulation: A primer","volume":"22","author":"Lo","year":"2007","journal-title":"IEEE Aerosp. Electron. Syst."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1017\/S037346330001256X","article-title":"GRI Ranking Based on Cross-Rate Interference in Loran-C","volume":"48","author":"Nieuwland","year":"1995","journal-title":"J. Navig."},{"key":"ref_21","unstructured":"Safar, J. (2014). Analysis, Modelling and Mitigation of Cross-Rate Interference in Enhanced Loran. [Ph.D. Thesis, Czech Technical University]."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"986","DOI":"10.1109\/TEMC.2005.854099","article-title":"Characterization of 100-kHz noise in the lightning current derivative signals measured at the CN tower","volume":"47","author":"Liatos","year":"2005","journal-title":"IEEE Trans. Electromagn. Compat."},{"key":"ref_23","unstructured":"Manish, L., Frank, G., Curtis, C., and David, D.D. (2003, January 3\u20137). Characterization of Atmospheric Noise in the LORAN-C Band. Proceedings of the International Loran Association (ILA)\u201432nd Annual Convention and Technical Symposium, Boulder, CO, USA."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"133","DOI":"10.2478\/v10367-012-0011-y","article-title":"Accuracy Performance of eLoran Receivers under Cross-Rate Interference Conditions","volume":"19","author":"Safar","year":"2012","journal-title":"Annu. Navig."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1002\/navi.202","article-title":"Analysis of Cross-Rate Interference Cancelation by Use of a Novel Phase Code Interval in Loran Navigation System","volume":"64","author":"Bayat","year":"2017","journal-title":"Navig. J. Inst. Navig."},{"key":"ref_26","unstructured":"Safar, J., Paul, W., Sally, B., and Frantisek, V. (2009, January 13\u201315). Cross-Rate Interference and Implications for Core eLoran Service Provision. Proceedings of the International Loran Association (ILA)\u201438nd Annual Convention and Technical Symposium, Portland, ME, USA."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1109\/MSP.2017.2714201","article-title":"High Sensitivity and Fast Acquisition Signal Processing Techniques for GNSS Receivers from fundamentals to state-of-the-art GNSS acquisition technologies","volume":"34","author":"Kong","year":"2017","journal-title":"IEEE Signal Process. Mag."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1172","DOI":"10.1109\/TAES.2012.6178098","article-title":"Comparison Between Ratio Detection and Threshold Comparison for GNSS Acquisition","volume":"48","author":"Geiger","year":"2012","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1109\/7.53421","article-title":"Digital accumulators in phase and frequency tracking loops","volume":"26","author":"Hinedi","year":"1990","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2483","DOI":"10.1109\/TIE.2010.2069070","article-title":"Phase-Locked Loop Noise Reduction via Phase Detector Implementation for Signal-Phase Systems","volume":"58","author":"Thacker","year":"2011","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Yang, M.H., Wu, H., Wang, Q.Q., Zhao, Y.X., and Liu, Z.Y. (2020). A BeiDou Signal Acquisition Approach Using Variable Length Data Accumulation Based on Signal Delay and Multiplication. Sensors, 20.","DOI":"10.3390\/s20051309"},{"key":"ref_32","unstructured":"Richard, G.L. (2004). Understanding Digital Signal Processing, Prentice Hall. [2nd ed.]."},{"key":"ref_33","first-page":"72","article-title":"A Pulse Detection Method Based on Judgment Threshold Automatic Recommendation","volume":"44","author":"Guo","year":"2019","journal-title":"Fire Control & Command Control"},{"key":"ref_34","unstructured":"Minimum Performance Standards for Marine eLORAN Receiving Equipment (2020, February 11). Radio Technical Commission for Maritime Services. Available online: https:\/\/2.zoppoz.workers.dev:443\/https\/rtcm.myshopify.com\/collections\/maritime-navigation-equipment-standards\/products\/copy-of-differential-gnss-package-both-of-the-current-standards-10402-3-and-10403-3."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/www.mdpi.com\/1424-8220\/20\/8\/2329\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:31:33Z","timestamp":1760362293000},"score":1,"resource":{"primary":{"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/www.mdpi.com\/1424-8220\/20\/8\/2329"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,4,19]]},"references-count":34,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2020,4]]}},"alternative-id":["s20082329"],"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/doi.org\/10.3390\/s20082329","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,4,19]]}}}