{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T04:31:11Z","timestamp":1781584271139,"version":"3.54.5"},"reference-count":23,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2022,5,18]],"date-time":"2022-05-18T00:00:00Z","timestamp":1652832000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Open Collective"},{"name":"Google Open Source"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The Google Smartphone Decimeter Challenge (GSDC) was a competition held in 2021, where data from a variety of instruments useful for determining a phone\u2019s position (signals from GPS satellites, accelerometer readings, gyroscope readings, etc.) using Android smartphones were provided to be processed\/assessed in regard to the most accurate determination of the longitude and latitude of user positions. One of the tools that can be utilized to process the GNSS measurements is RTKLIB. RTKLIB is an open-source GNSS processing software tool that can be used with the GNSS measurements, including code, carrier, and doppler measurements, to provide real-time kinematic (RTK), precise point positioning (PPP), and post-processed kinematic (PPK) solutions. In the GSDC, we focused on the PPK capabilities of RTKLIB, as the challenge only required post-processing of past data. Although PPK positioning is expected to provide sub-meter level accuracies, the lower quality of the Android measurements compared to geodetic receivers makes this performance difficult to achieve consistently. Another latent issue is that the original RTKLIB created by Tomoji Takasu is aimed at commercial GNSS receivers rather than smartphones. Therefore, the performance of the original RTKLIB for the GSDC is limited. Consequently, adjustments to both the code-base and the default settings are suggested. When implemented, these changes allowed RTKLIB processing to score 5th place, based on the performance submissions of the prior GSDC competition. Detailed information on what was changed, and the steps to replicate the final results, are presented in the paper. Moreover, the updated code-base, with all the implemented changes, is provided in the public repository. This paper outlines a procedure to optimize the use of RTKLIB for Android smartphone measurements, highlighting the changes needed given the low-quality measurements from the mobile phone platform (relative to the survey grade GNSS receiver), which can be used as a basis point for further optimization for future GSDC competitions.<\/jats:p>","DOI":"10.3390\/s22103825","type":"journal-article","created":{"date-parts":[[2022,5,18]],"date-time":"2022-05-18T23:14:26Z","timestamp":1652915666000},"page":"3825","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":33,"title":["Optimizing the Use of RTKLIB for Smartphone-Based GNSS Measurements"],"prefix":"10.3390","volume":"22","author":[{"given":"Tim","family":"Everett","sequence":"first","affiliation":[{"name":"RTK Consultants LLC, Niwot, CO 80503, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Trey","family":"Taylor","sequence":"additional","affiliation":[{"name":"Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO 80309, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4306-746X","authenticated-orcid":false,"given":"Dong-Kyeong","family":"Lee","sequence":"additional","affiliation":[{"name":"Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO 80309, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dennis M.","family":"Akos","sequence":"additional","affiliation":[{"name":"Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO 80309, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,5,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1002\/j.2161-4296.1999.tb02416.x","article-title":"Stochastic Modeling for Real-Time Kinematic GPS\/GLONASS Positioning","volume":"45","author":"Wang","year":"1999","journal-title":"Navigation"},{"key":"ref_2","unstructured":"Gakstatter, E., and GPS World (2022, April 01). RTK GNSS Receivers: A Flooded Market?. Available online: https:\/\/www.gpsworld.com\/rtk-gnss-receivers-a-flooded-market\/."},{"key":"ref_3","unstructured":"Bilich, A. (2022, April 01). National Geodetic Survey, Last Modified, Available online: https:\/\/geodesy.noaa.gov\/gps-toolbox\/exist.htm."},{"key":"ref_4","unstructured":"Takasu, T. (2009, January 20\u201323). RTKLIB: Open Source Program Package for RTK-GPS. Proceedings of the FOSS4G 2009, Tokyo, Japan."},{"key":"ref_5","unstructured":"IGS\/RTCM RINEX Working Group (2022, April 01). The Receiver Independent Exchange Format, Version 4.00. Available online: https:\/\/files.igs.org\/pub\/data\/format\/rinex_4.00.pdf."},{"key":"ref_6","unstructured":"(2021). Differential Global Navigation Satellite Systems Services, Version 3 (Standard No. RTCM Standard 10403.3). Available online: https:\/\/www.rtcm.org."},{"key":"ref_7","unstructured":"European Global Navigation Satellite Systems Agency (2022, April 01). 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Available online: https:\/\/rtkexplorer.com\/pdfs\/manual_demo5.pdf."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1671","DOI":"10.1016\/j.asr.2017.01.011","article-title":"The Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS)\u2014Achievements, Prospects and Challenges","volume":"59","author":"Montenbruck","year":"2017","journal-title":"Adv. Space Res."},{"key":"ref_20","unstructured":"Rokubun (2022, April 01). Android GNSS Logger to RINEX Converter. Available online: https:\/\/github.com\/rokubun\/android_rinex\/."},{"key":"ref_21","unstructured":"(2022, March 26). RTKLIB: Demo5. Available online: https:\/\/github.com\/rtklibexplorer\/RTKLIB\/."},{"key":"ref_22","unstructured":"Everett, T., and Rtklibexplorer (2022, April 01). Google Smartphone Decimeter Challenge. Available online: https:\/\/rtklibexplorer.wordpress.com\/2022\/01\/10\/google-smartphone-decimeter-challenge\/."},{"key":"ref_23","unstructured":"Everett, T., and Rtklibexplorer (2022, April 01). Another Look at L1\/L5 Cellphone PPK with RTKlib and an Xiaomi Mi8 Phone. Available online: https:\/\/rtklibexplorer.wordpress.com\/2021\/02\/27\/another-look-at-l1-l5-cellphone-ppk-with-rtklib\/."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/10\/3825\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:14:06Z","timestamp":1760138046000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/10\/3825"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,5,18]]},"references-count":23,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2022,5]]}},"alternative-id":["s22103825"],"URL":"https:\/\/doi.org\/10.3390\/s22103825","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,5,18]]}}}