{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T14:26:58Z","timestamp":1775744818340,"version":"3.50.1"},"reference-count":24,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2018,5,28]],"date-time":"2018-05-28T00:00:00Z","timestamp":1527465600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2017R1D1A1B03035207"],"award-info":[{"award-number":["2017R1D1A1B03035207"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The GPS provides positioning information almost anytime and anywhere on Earth, regardless of the weather conditions, and has become an essential technology for positioning and navigation. As a modernization program, the fourth civil GPS signal, denoted as L1C, will be transmitted from Block III satellites. One distinction of the L1C signal from the former signals is the use of binary offset carrier (BOC) modulation, which is necessary for compatibility and the reduction of interference between the legacy L1 signal and L1C signal, despite their use of the same carrier frequency. One drawback of using BOC modulation is the ambiguity problem, which comes from the multiple peaks in the correlation function and causes difficulties finding the code phase in the acquisition process. In this paper we suggest two delay-and-multiply (DM) methods for the L1C signal to solve the ambiguity problem. For the DM acquisition schemes we suggest the optimal delay time for the delay signal, and prove that the correlation function of the received DM signal and the generated DM signal has a triangular shape, as seen in the legacy GPS L1 signal. The noise characteristics of the decision variable are obtained and the performance of the DM acquisition scheme is given in terms of the probability of detection, and compared with that of the conventional method. We provide the procedure to find the Doppler frequency after obtaining the code phase through the proposed DM method.<\/jats:p>","DOI":"10.3390\/s18061739","type":"journal-article","created":{"date-parts":[[2018,5,29]],"date-time":"2018-05-29T02:58:18Z","timestamp":1527562698000},"page":"1739","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["An Unambiguous Delay-And-Multiply Acquisition Scheme for GPS L1C Signals"],"prefix":"10.3390","volume":"18","author":[{"given":"Duk-Sun","family":"Shim","sequence":"first","affiliation":[{"name":"School of Electrical and Electronics Engineering, Chung-Ang University, 84 Huksuk-ro, Dongjak-ku, Seoul 06974, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jin-Seok","family":"Jeon","sequence":"additional","affiliation":[{"name":"School of Electrical and Electronics Engineering, Chung-Ang University, 84 Huksuk-ro, Dongjak-ku, Seoul 06974, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,5,28]]},"reference":[{"key":"ref_1","unstructured":"Kaplan, E.D., and Hegarty, C.J. (2006). Understanding GPS: Principles and Applications, Artech House. [2nd ed.]."},{"key":"ref_2","unstructured":"Borre, K., Akos, D.M., Bertelsen, N., Rinder, P., and Jensen, S.H. (2007). A Software-Defined GPS and Galileo Receiver: A Single-Frequency Approach, Birkhauser."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Tsui, J.-Y. (2005). Fundamentals of Global Positioning System Receivers: A Software Approach, John Wiley & Sons. [2nd ed.].","DOI":"10.1002\/0471712582"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"723","DOI":"10.5370\/JEET.2011.6.5.723","article-title":"Rapid Acquisition of CM and CL Code for GPS L2C Software Receivers","volume":"6","author":"Kwon","year":"2011","journal-title":"J. Electr. Eng. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1133","DOI":"10.1007\/s12555-015-0091-2","article-title":"Fast Acquisition of GPS L5 PRN and NH Code Using L1 Signal for Software Receivers","volume":"14","author":"Lee","year":"2016","journal-title":"Int. J. Control Autom. Syst."},{"key":"ref_6","unstructured":"Michael, J.D. (2013). Navstar GPS Space Segment\/User Segment L1C Interface, IS-GPS-800D, Science Applications International Corporation."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1002\/j.2161-4296.2007.tb00394.x","article-title":"The Spreading and Overlay Codes for the L1C Signal","volume":"54","author":"Rushanan","year":"2007","journal-title":"J. Inst. Navig."},{"key":"ref_8","unstructured":"European Union (2014). European GNSS (Galileo) Open Service Signal in Space Interface Control Document, European Union."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Nurmi, J., Lohan, E.S., Sand, S., and Hurskainen, H. (2015). GALILEO Positioning Technology, Springer.","DOI":"10.1007\/978-94-007-1830-2"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1002\/wcm.407","article-title":"Binary-Offset-Carrier modulation techniques with applications in satellite navigation systems","volume":"7","author":"Lohan","year":"2007","journal-title":"Wirel. Commun. Mob. Comput."},{"key":"ref_11","unstructured":"Martin, N., Leblond, V., Guillotel, G., and Heiries, V. (2003, January 9\u201312). BOC(x,y) signal acquisition techniques and performance. Proceedings of the ION GPS\/GNSS, Portland, OR, USA."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"502","DOI":"10.12928\/telkomnika.v13i2.1469","article-title":"Unambiguous Sin-phased BOC(kn,n) Signal Acquisition Based on Combined Correlation Functions","volume":"13","author":"Deng","year":"2015","journal-title":"TELKOMNIKA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1109\/MAES.2011.5763340","article-title":"Interoperable GPS, GLONASS and Galileo Software receiver","volume":"26","author":"Kovar","year":"2011","journal-title":"IEEE Aerosp. Electron. Syst. Mag."},{"key":"ref_14","unstructured":"Heiries, V., Roviras, D., Ries, L., and Calmettes, V. (2004, January 22\u201324). Analysis of Non Ambiguous BOC Signal Acquisition Performance. Proceedings of the U.S. Institute of Navigation GNSS Conference, Long Beach, CA, USA."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1109\/TAES.2007.357123","article-title":"ASPeCT: Unambiguous Sine-BOC(n,n) Acquisition\/Tracking Technique for Navigation Applications","volume":"43","author":"Julien","year":"2007","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_16","first-page":"738183","article-title":"Data and Pilot Combining for Composite GNSS Signal acquisition","volume":"2008","author":"Borio","year":"2008","journal-title":"Int. J. Navig. Obs."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1782","DOI":"10.1109\/TAES.2010.5595594","article-title":"Pseudo-Correlation-Function-Based Unambiguous Tracking Technique for Sine-BOC Signals","volume":"46","author":"Yao","year":"2010","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1587\/elex.11.20140979","article-title":"A novel acquisition scheme for Galileo E1 OS Signals","volume":"11","author":"Xi","year":"2014","journal-title":"IEICE Electron. Express"},{"key":"ref_19","first-page":"950","article-title":"Unambiguous Acquisition for Galileo E1 OS Signal Based on Delay and Multiply","volume":"29","author":"Deng","year":"2014","journal-title":"TELKOMNIKA"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2848","DOI":"10.1007\/s12555-017-9367-z","article-title":"New Unambiguous Delay-and-Multiply Acquisition Schemes for Galileo E1 OS Signals and its Performance Analysis","volume":"15","author":"Shim","year":"2017","journal-title":"Int. J. Control Autom. Syst."},{"key":"ref_21","unstructured":"Sun, D., Cui, X., Zhu, Y., and Lu, M. (2015, January 26\u201328). Fast acquisition algorithm of GPS L1C signal based on the Sparse Fast Fourier Transform. Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation, Dana Point, CA, USA."},{"key":"ref_22","unstructured":"Seals, K.C., Michalson, W.R., Swaszek, P.F., and Hartnett, R.J. (2012, January 17\u201321). Analysis of Coherent Combining for GPS L1C Acquisition. Proceedings of the 25th International Technical Meeting of the Satellite Division of the Institute of Navigation, Nashville, TN, USA."},{"key":"ref_23","unstructured":"Seals, K.C., Michalson, W.R., Swaszek, P.F., and Hartnett, R.J. (2013, January 16\u201320). Using Both GPS L1 C\/A and L1C: Strategies to Improve Acquisition Sensitivity. Proceedings of the 26th International Technical Meeting of the Satellite Division of the Institute of Navigation, Nashville, TN, USA."},{"key":"ref_24","first-page":"190465","article-title":"Combined Acquisition and Tracking Methods for GPS L1 CA and L1C Signals","volume":"2010","author":"Petovello","year":"2010","journal-title":"Int. J. Navig. Obs."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/6\/1739\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:06:16Z","timestamp":1760195176000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/6\/1739"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,5,28]]},"references-count":24,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2018,6]]}},"alternative-id":["s18061739"],"URL":"https:\/\/doi.org\/10.3390\/s18061739","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,5,28]]}}}