<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>As approved and supported by the IGS GB and IC, we hereby invite your participation in a task force to develop a format standard on the satellite product combination statistics over all involved AC-specific products (e.g., satellite orbits, clocks, biases, etc.). The initiative is to improve the representation, interoperability, and usability of such statistics to facilitate the quality control by AC developers and PPP users.</div><div><br></div><div>Current Challenges</div><div><br></div><div>The existing ‘standard summary’ file format for the combination statistics presents some limitations, such as</div><div>(1) Lack of readability and compliance with a dedicated format standard.</div><div>(2) No statistics for the combined bias products.</div><div>(3) Incomplete product descriptions: Impedes transparency and access to key information.</div><div>(4) Insufficient quality assessment details: Excludes essential diagnostics such as anomalous satellites, outliers, and discontinuities.</div><div><br></div><div>To address these issues, we propose to develop a new format standard for the product combination statistics with the following key features,</div><div>(1) Compliance with an established format standard: Ensures consistency and compatibility with established geodetic standards.</div><div>(2) Comprehensive quality information: Includes reference details, comments, Helmert parameters, bias products, discontinuities, and other critical metrics.</div><div>(3) User-friendly data processing: Designed to simplify the workflow for end-users, facilitating easier interpretation and application of the data</div><div><br></div><div>We warmly invite institutions and individuals interested in this effort to join the development and implementation of the new format. Your expertise and feedback will be essential to building a robust, efficient, and widely adopted standard that strengthens the quality and transparency of IGS combined products. Please contact jgeng@apm.ac.cn to express your interest to participate.</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<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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