{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T23:51:45Z","timestamp":1762300305634,"version":"build-2065373602"},"reference-count":33,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2023,2,12]],"date-time":"2023-02-12T00:00:00Z","timestamp":1676160000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key R&amp;D Program of China","award":["2021YFA0716603"],"award-info":[{"award-number":["2021YFA0716603"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>To guarantee the integrity of a global navigation satellite system (GNSS) for safety-critical users, a satellite-based augmentation system (SBAS) makes use of the integrity monitoring architecture, of which the signal quality monitor (SQM) is an important component to address the potential risks caused by satellite-induced signal anomalies. Due to the introduction of dual-frequency multi-constellation (DFMC) techniques in 2025, the ranging uncertainty will be reduced by the elimination of first-order ionospheric delay, but the biases measured in each individual signal will be inflated by the ionosphere-free combinations. Moreover, multiple modulations of DFMC signals might introduce applicability uncertainty of a traditional SQM method that has been protecting GPS L1C\/A signal only. Thus, higher requirements are put forward for future SQM methods in detection sensitivity and modulation independence. This paper first proposes a design methodology for the SQM algorithm for BDS B1C\/B2a signals, which could be easily extended to the DF combinations of other GNSS core constellations. Then, by comparing the performances of SQM baseline algorithms based on traditional multi-correlator and emerging chip domain observables (CDOs), respectively, the superiority of CDO-based SQM is declared. Detailed design iterations are further discussed, including the algorithm practicalization with optimizing code-phase bin length and lowering sampling frequency, as well as the metric simplification, to promote the overall performance while preserving a lower implementation complexity. Ultimately, a CDO-based SQM algorithm for BDS B1C\/B2a signals is reached, which would be considered as an effective candidate in new generation DFMC SBASs.<\/jats:p>","DOI":"10.3390\/rs15041008","type":"journal-article","created":{"date-parts":[[2023,2,13]],"date-time":"2023-02-13T01:48:56Z","timestamp":1676252936000},"page":"1008","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Designing the Signal Quality Monitoring Algorithm Based on Chip Domain Observables for BDS B1C\/B2a Signals under the Requirements of DFMC SBAS"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9623-5370","authenticated-orcid":false,"given":"Xiang","family":"Wang","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering, Tsinghua University, Beijing 100084, China"},{"name":"State Key Laboratory of Geo-Information Engineering, Xi\u2019an 710054, China"}]},{"given":"Xiaowei","family":"Cui","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Tsinghua University, Beijing 100084, China"}]},{"given":"Gang","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Tsinghua University, Beijing 100084, China"}]},{"given":"Mingquan","family":"Lu","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Tsinghua University, Beijing 100084, China"},{"name":"Beijing National Research Center for Information Science and Technology, Tsinghua University, Beijing 100084, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,12]]},"reference":[{"key":"ref_1","unstructured":"International Civil Aviation Organization (2018). International Standards and Recommended Practices, International Civil Aviation Organization. [7th ed.]."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1063","DOI":"10.1109\/5.533954","article-title":"Wide area augmentation of the Global Positioning System","volume":"84","author":"Enge","year":"1996","journal-title":"Proc. IEEE"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Gao, W., Cao, Y., Liu, C., Lu, J., Shao, B., Xiong, S., and Su, C. (2022). Construction Progress and Aviation Flight Test of BDSBAS. Remote Sens., 14.","DOI":"10.3390\/rs14051218"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"405","DOI":"10.1002\/navi.422","article-title":"Development of BeiDou Satellite-Based Augmentation System","volume":"68","author":"Liu","year":"2021","journal-title":"Navigation"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1186\/s43020-022-00070-6","article-title":"Satellite integrity monitoring for satellite-based augmentation system: An improved covariance-based method","volume":"3","author":"Zheng","year":"2022","journal-title":"Satell. Navig."},{"key":"ref_6","unstructured":"Phelts, R.E. (2001). Multi-correlator Techniques for Robust Mitigation of Threats to GPS Signal Quality. [Ph.D. Thesis, Stanford University]. Available online: http:\/\/web.stanford.edu\/group\/scpnt\/gpslab\/pubs\/theses\/EricPheltsThesis01.pdf."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"navi.543","DOI":"10.33012\/navi.543","article-title":"Signal Quality Monitoring Based on Chip Domain Observables: Theory, Design, and Implementation","volume":"69","author":"Wang","year":"2022","journal-title":"Navigation"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Shallberg, K.W., Ericson, S.D., Phelts, R.E., Walter, T., Kovach, K., and Altshuler, E. (February, January 30). Catalog and Description of GPS and WAAS L1 C\/A Signal Deformation Events. Proceedings of the ION ITM 2017, Institute of Navigation, Monterey, CA, USA.","DOI":"10.33012\/2017.14877"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1002\/navi.252","article-title":"WAAS at 15","volume":"65","author":"Walter","year":"2018","journal-title":"Navigation"},{"key":"ref_10","unstructured":"Phelts, R.E., Walter, T., and Enge, P. (2003, January 9\u201312). Toward Real-Time SQM for WAAS: Improved Detection Techniques. Proceedings of the ION GPS\/GNSS 2003, Institute of Navigation, Portland, OR, USA. Available online: https:\/\/www.ion.org\/publications\/abstract.cfm?articleID=5462."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1002\/navi.218","article-title":"Signal Quality Monitoring for New GNSS Signals","volume":"65","author":"Pagot","year":"2018","journal-title":"Navigation"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1002\/navi.21","article-title":"Evolving WAAS to Serve L1\/L5 Users","volume":"59","author":"Walter","year":"2012","journal-title":"Navigation"},{"key":"ref_13","unstructured":"Phelts, R.E., Wong, G., Walter, T., and Enge, P. (2013, January 27\u201329). Signal Deformation Monitoring for Dual-Frequency WAAS. Proceedings of the ION ITM 2013, Institute of Navigation, San Diego, CA, USA. Available online: https:\/\/www.ion.org\/publications\/abstract.cfm?articleID=10817."},{"key":"ref_14","unstructured":"Fenton, P.C., and Jones, J. (2005, January 13\u201316). The Theory and Performance of NovAtel Inc.\u2019s Vision Correlator. Proceedings of the ION GNSS 2005, Institute of Navigation, Long Beach, CA, USA."},{"key":"ref_15","unstructured":"Weill, L.R. (2007, January 25\u201328). Theory and Applications of Signal Compression in GNSS Receivers. Proceedings of the ION GNSS 2007, Institute of Navigation, Fort Worth, TX, USA."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1007\/s10291-022-01332-1","article-title":"Efficient chip-shape correlator implementation on a GPU-based real-time GNSS SDR receiver","volume":"26","author":"Wang","year":"2022","journal-title":"GPS Solut."},{"key":"ref_17","unstructured":"Thevenon, P., Pagot, J.-B., Julien, O., and Tessier, Q. (2014, January 3\u20135). Processing Technique and Performance of the Observation of Evil Waveform in the Chip Domain. Proceedings of the IEEE NAVITEC 2014, ESA, Noordwijk, The Netherlands. Available online: https:\/\/hal-enac.archives-ouvertes.fr\/hal-01094193."},{"key":"ref_18","unstructured":"Pagot, J.-B., Thevenon, P., Julien, O., Gregoire, Y., Fern\u00e1ndez, F.A., and Maillard, D. (2015, January 26\u201328). Estimation of GNSS Signals\u2019 Nominal Distortions from Correlation and Chip Domain. Proceedings of the ION ITM 2015, Institute of Navigation, Dana Point, CA, USA. Available online: https:\/\/www.ion.org\/publications\/abstract.cfm?articleID=12640."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Li, R.D., Tang, X.M., and Ou, G. (2017, January 3\u20135). GNSS Signal Quality Analysis Technique Based on Chip Measurement. Proceedings of the IEEE ITOEC 2017, Chongqing, China.","DOI":"10.1109\/ITOEC.2017.8122339"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Wang, X., Gao, Y., Cui, X.W., Liu, G., and Lu, M.Q. (2021, January 25\u201328). A Signal Quality Monitoring Algorithm Based on Chip Domain Observables for BDS B1C signal. Proceedings of the ION ITM 2021, Institute of Navigation, Virtual.","DOI":"10.33012\/2021.17810"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Liu, C., Cao, Y.-L., Zhang, G., Gao, W.-G., Chen, J., Lu, J., Liu, C.-H., and Zhao, H.-T. (2021). Design and Performance Analysis of BDS-3 Integrity Concept. Remote Sens., 13.","DOI":"10.3390\/rs13152860"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Chen, L., Gao, W.G., Hu, Z.G., Cao, Y.L., Pei, L., Liu, C., Zhou, W., Liu, X.Z., Chen, L., and Yang, R.H. (2022). BDS-3 Integrity Risk Modeling and Probability Evaluation. Remote Sens., 14.","DOI":"10.3390\/rs14040944"},{"key":"ref_23","unstructured":"International Civil Aviation Organization (2018). DFMC SBAS SARPs\u2014Part B, Version 2.0. NSP, DS2\/WP\/3 v2.0, International Civil Aviation Organization."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1002\/navi.296","article-title":"Overview of BDS III new signals","volume":"66","author":"Lu","year":"2019","journal-title":"Navigation"},{"key":"ref_25","unstructured":"China Satellite Navigation Office (2020, October 09). BeiDou Navigation Satellite System Signal in Space Interface Control Document, Open Service Signal B1C (Version 1.0), Available online: http:\/\/www.beidou.gov.cn\/xt\/gfxz\/201712\/P020171226741342013031.pdf."},{"key":"ref_26","unstructured":"China Satellite Navigation Office (2020, October 09). BeiDou Navigation Satellite System Signal in Space Interface Control Document, Open Service Signal B2a (Version 1.0), Available online: http:\/\/www.beidou.gov.cn\/xt\/gfxz\/201712\/P020171226742357364174.pdf."},{"key":"ref_27","unstructured":"Cui, X.W. (2020, January 5). Applicability Analysis of the Filter Gain Roll-off in DFMC SBAS Receiver Design Constraints for BDS B1C and B2a Signals. Proceedings of the ICAO, NSP, JWGs\/6-WP\/24, Virtual."},{"key":"ref_28","unstructured":"Shloss, P., Phelts, R.E., Walter, T., and Enge, P. (2002, January 24\u201327). A Simple Method of Signal Quality Monitoring for WAAS LNAV\/VNAV. Proceedings of the ION GPS 2002, Institute of Navigation, Portland, OR, USA. Available online: https:\/\/www.ion.org\/publications\/abstract.cfm?articleID=2083."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1186\/s43020-020-00011-1","article-title":"Estimation method of SBAS dual-frequency range error integrity parameter","volume":"1","author":"Shao","year":"2020","journal-title":"Satell. Navig."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Wang, X., Cui, X.W., Wei, K.F., Liu, G., Gao, Y., and Lu, M.Q. (2021, January 26\u201328). Signal Quality Monitoring Algorithms of DFMC SBAS for Dual-Frequency Civil Signals of BDS. Proceedings of the CSNC 2021, Nanchang, China. Lecture Notes in Electrical Engineering Volume 773.","DOI":"10.1007\/978-981-16-3142-9_8"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Wang, X., Cui, X.W., Liu, G., Tian, Z.Y., and Lu, M.Q. (2022, January 25\u201327). Performance Evaluation of Two Kinds of Evil Correlation Function Generation Methods for Signal Deformation Monitoring. Proceedings of the ION ITM 2022, Institute of Navigation, Long Beach, CA, USA.","DOI":"10.33012\/2022.18238"},{"key":"ref_32","unstructured":"NovAtel (2012). GNSS-750 Antenna Guide, OM-20000120, Rev 5, NovAtel Inc."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Wang, X., Cui, X.W., Liu, G., Qi, H.T., and Lu, M.Q. (2022, January 19\u201323). Necessity and Modeling of the Satellite-induced Elevation-dependent Signal Anomalies for SBAS Integrity Monitoring. Proceedings of the ION GNSS+ 2022, Institute of Navigation, Denver, CO, USA.","DOI":"10.33012\/2022.18520"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/4\/1008\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:32:12Z","timestamp":1760121132000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/4\/1008"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,2,12]]},"references-count":33,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["rs15041008"],"URL":"https:\/\/doi.org\/10.3390\/rs15041008","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2023,2,12]]}}}