doi:10.1109/LRA.2025.3641442engCerezo, SamuelCivera, JavierGNSS-Inertial State Initialization Using Inter-Epoch Baseline ResidualsART-2026-147254Initializing the state of a sensorized platform can be challenging, as a limited set of measurements often provide low-informative constraints that are in addition highly non-linear. This may lead to poor initial estimates that may converge to local minima during subsequent non-linear optimization. We propose an adaptive GNSS–inertial initialization strategy that delays the incorporation of global GNSS constraints until they become sufficiently informative. In the initial stage, our method leverages inter-epoch baseline vector residuals between consecutive GNSS fixes to mitigate inertial drift. To determine when to activate global constraints, we introduce a general criterion based on the evolution of the Hessian matrix's singular values, effectively quantifying system observability. Experiments on EuRoC, GVINS and MARS-LVIG datasets show that our approach consistently outperforms the naive strategy of fusing all measurements from the outset, yielding more accurate and robust initializations.2026http://zaguan.unizar.es/record/16551210.1109/LRA.2025.3641442http://zaguan.unizar.es/record/165512oai:zaguan.unizar.es:165512info:eu-repo/grantAgreement/ES/DGA/T45-23Rinfo:eu-repo/grantAgreement/ES/MICINN/PID2021-127685NB-I00info:eu-repo/grantAgreement/EUR/MICINN/TED2021-131150B-I00IEEE Robotics and Automation Letters 11, 2 (2026), 1458-1465All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/closedAccess