{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T10:49:20Z","timestamp":1761648560385,"version":"build-2065373602"},"reference-count":29,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2018,4,25]],"date-time":"2018-04-25T00:00:00Z","timestamp":1524614400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Signal modulation is an essential design factor of a positioning system, which directly impacts the system\u2019s potential performance. Chirp compressions have been widely applied in the fields of communication, radar, and indoor positioning owing to their high compression gain and good resistance to narrowband interferences and multipath fading. Based on linear chirp, we present a modulation method named chirped pseudo-noise (ChPN). The mathematical model of the ChPN signal is provided with its auto-correlation function (ACF) and the power spectrum density (PSD) derived. The ChPN with orthogonal chirps is also discussed, which has better resistance to near-far effect. Then the generation and detection methods as well as the performances of ChPN are discussed by theoretical analysis and simulation. The results show that, for ChPN signals with the same main-lobe bandwidth (MLB), generally, the signal with a larger sweep bandwidth has better tracking precision and multipath resistance. ChPN yields slighter ACF peaks ambiguity due to its lower ACF side-peaks, although its tracking precision is a little worse than that of a binary offset carrier (BOC) with the same MLB. Moreover, ChPN provides better overall anti-multipath performance than BOC. For the ChPN signals with the same code rate, a signal with a larger sweep bandwidth has better performance in most aspects. In engineering practice, a ChPN receiver can be implemented by minor modifications of a BOC receiver. Thus, ChPN modulation shows promise for future positioning applications.<\/jats:p>","DOI":"10.3390\/s18051326","type":"journal-article","created":{"date-parts":[[2018,4,25]],"date-time":"2018-04-25T03:22:45Z","timestamp":1524626565000},"page":"1326","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["A Low-Ambiguity Signal Waveform for Pseudolite Positioning Systems Based on Chirp"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5157-5996","authenticated-orcid":false,"given":"Qing","family":"Liu","sequence":"first","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhigang","family":"Huang","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yanhong","family":"Kou","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jinling","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,4,25]]},"reference":[{"key":"ref_1","unstructured":"Trunzo, A., Benshoof, P., Squadron, T., Afb, H., and Nm, J. (2011, January 20\u201323). The UHARS Non-GPS Based Positioning System. Proceedings of the 24th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS 2011), Portland, OR, USA."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Rizos, C., Roberts, G., Barnes, J., and Gambale, N. (2010, January 15\u201317). Locata: A new high accuracy indoor positioning system. Proceedings of the 2010 International Conference on Indoor Positioning and Indoor Navigation, Zurich, Switzerland.","DOI":"10.1109\/IPIN.2010.5647717"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Rizos, C., Roberts, G., Barnes, J., and Gambale, N. (2010, January 15\u201317). Experimental results of Locata: A high accuracy indoor positioning system. Proceedings of the 2010 International Conference on Indoor Positioning and Indoor Navigation, Zurich, Switzerland.","DOI":"10.1109\/IPIN.2010.5647717"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1007\/s10291-008-0097-9","article-title":"Ultra-tight GPS\/INS\/PL integration: A system concept and performance analysis","volume":"13","author":"Babu","year":"2009","journal-title":"GPS Solut."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1002\/j.2161-4296.2007.tb00407.x","article-title":"Indoor geolocation using FCDMA pseudolites: Signal structure and performance analysis","volume":"54","author":"Progri","year":"2007","journal-title":"Navigation"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1007\/s10291-018-0697-y","article-title":"Precise point positioning for ground-based navigation systems without accurate time synchronization","volume":"22","author":"Guo","year":"2018","journal-title":"GPS Solut."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Li, X., Zhang, P., Guo, J., Wang, J., and Qiu, W. (2017). A New Method for Single-Epoch Ambiguity Resolution with Indoor Pseudolite Positioning. Sensors, 17.","DOI":"10.3390\/s17040921"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1721","DOI":"10.1007\/s10291-017-0647-0","article-title":"Improved GNSS-based indoor positioning algorithm for mobile devices","volume":"21","author":"Xu","year":"2017","journal-title":"GPS Solut."},{"key":"ref_9","unstructured":"Kurz, O., Mongr\u00e9dien, C., and Rohmer, G. (2013, January 16\u201320). A new multipath detection and mitigation approach for pseudolite systems. Proceedings of the 26th International Technical Meeting of the ION Satellite Division (ION GNSS+ 2013), Nashville, TN, USA."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"561","DOI":"10.1007\/s10291-016-0547-8","article-title":"BS-ACEBOC: A generalized low-complexity dual-frequency constant-envelope multiplexing modulation for GNSS","volume":"21","author":"Guo","year":"2017","journal-title":"GPS Solut."},{"key":"ref_11","unstructured":"(2018, April 24). Locata Signal Interface Control Document. Available online: http:\/\/www.locata.com\/wp-content\/uploads\/2014\/07\/Locata-ICD-100E.pdf."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3949","DOI":"10.1109\/TCOMM.2016.2594792","article-title":"Orthogonal chirp division multiplexing","volume":"64","author":"Ouyang","year":"2016","journal-title":"IEEE Trans. Commun."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3519","DOI":"10.1109\/TGRS.2007.906140","article-title":"Signal Processing for FMCW SAR","volume":"45","author":"Meta","year":"2007","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1146","DOI":"10.1109\/TAES.2016.140656","article-title":"Digital linear chirp receiver for high chirp rates with high resolution time-of-arrival and time-of-departure estimation","volume":"52","author":"Benson","year":"2016","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"19","DOI":"10.2528\/PIER13071206","article-title":"A refined two-dimensional nonlinear chirp scaling algorithm for geosynchronous earth orbit SAR","volume":"143","author":"Zeng","year":"2013","journal-title":"Prog. Electromagn. Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2715","DOI":"10.1109\/TGRS.2007.900673","article-title":"Ultrawideband Radar Measurements of Thickness of Snow Over Sea Ice","volume":"45","author":"Kanagaratnam","year":"2007","journal-title":"IEEE Trans. Geosc. Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"885","DOI":"10.1109\/JSAC.2005.863879","article-title":"Multicode ultra-wideband scheme using chirp waveforms","volume":"24","author":"Liu","year":"2006","journal-title":"IEEE J. Select. Areas Commun."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1155\/2014\/310410","article-title":"Probabilistic Error Modeling and Topology-Based Smoothing of Indoor Localization and Tracking Data, Based on the IEEE 802.15.4a Chirp Spread Spectrum Specification","volume":"10","author":"Segou","year":"2014","journal-title":"Int. J. Distrib. Sens. Netw."},{"key":"ref_19","unstructured":"Ling, H., Yilong, L., and Liu, W. (2010, January 28\u201330). Using chirp signal for accurate RFID positioning. Proceedings of the 2010 International Conference on Communications, Circuits and Systems (ICCCAS), Chengdu, China."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Pivato, P., Dalpez, S., and Macii, D. (2012, January 20\u201322). Performance evaluation of Chirp Spread Spectrum ranging for indoor embedded navigation systems. Proceedings of the 7th IEEE International Symposium on Industrial Embedded Systems, Karlsruhe, Germany.","DOI":"10.1109\/SIES.2012.6356603"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1361","DOI":"10.1016\/j.comcom.2011.02.002","article-title":"Experimental analysis of IEEE 802.15.4a CSS ranging and its implications","volume":"34","author":"Yoon","year":"2011","journal-title":"Comput. Commun."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Nunes, F.D., Leitao, J.M., and Sousa, F.M. (2016, January 14\u201316). Performance analysis of an absolute phase modulation scheme for GNSS signals. Proceedings of the 8th ESA Workshop onSatellite Navigation Technologies and European Workshop on GNSS Signals and Signal Processing (NAVITEC), Noordwijk, The Netherlands.","DOI":"10.1109\/NAVITEC.2016.7849331"},{"key":"ref_23","unstructured":"Cook, C. (2012). Radar Signals: An Introduction to Theory and Application, Elsevier."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1133","DOI":"10.1109\/TCOM.1983.1095745","article-title":"A Spread-Spectrum Concept Combining Chirp Modulation and Pseudonoise Coding","volume":"31","author":"Kowatsch","year":"1983","journal-title":"IEEE Trans. Commun."},{"key":"ref_25","unstructured":"Rebeyrol, E., Macabiau, C., Lestarquit, L., Ries, L., Issler, J.L., Boucheret, M.L., and Bousquet, M. (2005, January 24\u201326). BOC power spectrum densities. Proceedings of the 2005 National Technical Meeting of The Institute of Navigation, San Diego, CA, USA."},{"key":"ref_26","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. Syst."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1557","DOI":"10.1109\/TAES.2009.5310317","article-title":"Generalized Theory of Code Tracking with an Early-Late Discriminator Part II: Noncoherent Processing and Numerical Results","volume":"45","author":"Betz","year":"2009","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_28","unstructured":"Kaplan, E. (2006). Understanding GPS: Principles & Applications, Artech House. [2nd ed.]."},{"key":"ref_29","unstructured":"Zuping, T. (2009). Research on releVant Theory for GNSS Signal Design and Evaluation, HUST."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/5\/1326\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:02:04Z","timestamp":1760194924000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/5\/1326"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,4,25]]},"references-count":29,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2018,5]]}},"alternative-id":["s18051326"],"URL":"https:\/\/doi.org\/10.3390\/s18051326","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2018,4,25]]}}}