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<p class="MsoNormal"><span lang="EN-US">Dear Colleagues,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Please consider submitting an abstract to this dedicated Precision Orbit Determination session organized at the
</span><a href="https://www.eventsforce.net/eumetsat/frontend/reg/thome.csp?pageID=31367&eventID=81"><span lang="EN-US">2026 OSTST</span></a><span lang="EN-US">, to be held in Wiesbaden, Germany, 22-26 June 2026. The deadline for abstract submission is April
3, 2026.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Our splinter’s description:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Precision orbit determination underpins the accuracy and quality of the data for all altimeter missions. With a thirty-year long altimeter record from six missions on the reference orbit (TOPEX/Poseidon, Jason-1, Jason-2/OSTM,
Jason-3, Sentinel-6A/B) and from several others on lower orbits (ERS, Envisat, CryoSat-2, HY-2A/-2B/-2C/-2D, SARAL/AltiKa, Sentinel-3A/B, SWOT), the focus is now on the long-term stability of the orbit solutions and on the impact of geographically correlated
errors on both the global and regional Mean Sea Level estimates. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">The most critical issues concern the stability of the reference frame for computing the orbits, the accuracy and fidelity of the force models that underpin the POD computations and the overall quality of the available
tracking data. We monitor closely the performance of the tracking systems onboard the current flight missions (especially Jason-3 and Sentinel-6) but we are also interested in the general performance of the SLR, DORIS, and GNSS networks used for orbit determination.
The stability of the reference frame and the tracking systems, and the consistency between the orbits produced by the different geodetic techniques contributes to the error budget for the altimetric data and the science products. The new reference frames realizations
for ITRF2020 show improvement with respect to ITRF2014, and we are especially interested in their application to satellite altimetry POD for each of the techniques. Each of the geodetic techniques has systematic errors that impact the measurements which affect
the POD stability and accuracy on both the short- and the long-term. With the stringent radial orbit accuracy requirements, the refinement of the satellite force and measurement modelling continues to be essential.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">We encourage papers that discuss the latest models that are applicable for satellite altimetry POD given the operational constraints of latency and the timely delivery of GDR products. The POD splinter brings together
POD specialists with altimetry users so that the two communities can interact. POD specialists gather during the splinter to discuss their latest results but they are also there to answer questions from the community. The goal of the POD splinter is to ensure
that spurious orbit-related signals do not contaminate the altimetric products on medium-term or long-term time scales, and to help ensure that altimetric data across different missions from different orbits can be compared and combined in a seamless fashion.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">We are looking forward to discussing with you in Wiesbaden!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">On behalf of the co-chairs of the session,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Alex Conrad, Alexandre Couhert, Frank Lemoine and Carlos Fernández Martín
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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