<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div>Dear colleagues,</div><div><br></div><div>We are pleased to announce that PRIDE-PPPAR version 3.2 software with the “AI for integer ambiguity validation” function has been released at https://github.com/PrideLab/PRIDE-PPPAR.</div><div><br></div><div>In this new version, a machine learning (ML) based model is used by default for undifferenced integer ambiguity validation, while the classic “Ratio Test” remains available as an alternative option. The model is based on the XGBoost (eXtreme Gradient Boosting) and trained using globally distributed GNSS data from the IGS. It validates undifferenced integer ambiguity candidates through several representative and classic indices, i.e., R-ratio value, W-ratio value, Difference Test, Projector Test, ADOP and the Ambiguity-Penalized Test. This AI model supports ambiguity validation for all processing modes (e.g., static and kinematic), batch lengths (e.g., 20 minutes up to 6 hours), and constellations (GPS, Galileo, BDS, and multi-GNSS).</div><div><br></div><div>Extensive evaluations over datasets from the past five years demonstrate that the AI model achieves decent improvements over the ratio test with a pre-determined threshold. Depending on processing strategies, the correctness rate of ambiguity validation using the AI model can be 5-10 percentage points higher than the ratio test, especially for data of short span (e.g., 20 minutes). In particular, for the GNSS kinematic processing using 20 minutes to 2 hours of data, the 3D positioning RMS error is 9 cm on average for AI-validated solutions, compared to 14 cm for those by the ratio test, suggesting again that this AI model has higher success rates in validating integer ambiguities.</div><div><br></div><div>In addition, two more updates,</div><div>1) The online repository for the WUM0MGXRAP products has been moved to ftps://bdspride.com permanently. The Wuhan University repository (ftp://igs.gnsswhu.cn/pub/whu/phasebias) will still be updated but not guaranteed. </div><div>2) A new “-wcc” option has been introduced to the “pdp3” command line, allowing PPP users to directly utilize the combined final products from the Wuhan Combination Center (WCC).</div><div><br></div><div>We warmly invite all interested colleagues to evaluate this new version with a “primitive” AI capability. Your feedback and suggestions are highly appreciated and will help us further improve the software. This work is funded by National Science Foundation of China (No. 42025401, 42361134580) and under the auspices of IAG Sub-Commission 4.2 “Multi-constellation and multi-frequency GNSS” and IGS “Bias & Ambiguity Resolution (BAR)” committee.</div><div><br></div><div>Reference</div><div><br></div><div>Guo, J., Geng, J. Integer ambiguity validation through machine learning for precise point positioning. Satell Navig 6, 14 (2025). https://doi.org/10.1186/s43020-025-00167-8</div><div><br></div><div><br></div><div>With best regards,</div><div>
<div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div>Jianghui Geng on behalf of the PRIDE Group including Qiang WEN and Jiang GUO.<br>Professor in GNSS Geodesy<br>Director of State Key Laboratory of Precision Geodesy,</div><div>APM, Chinese Academy of Sciences, Wuhan, China<br>Email: jgeng@apm.ac.cn<br>Office: +86 (0)27 68881316<br>Homepage: http://pride.apm.ac.cn<br><br>Earn the right to be wrong</div><div><br></div></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"><br class="Apple-interchange-newline">
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