Abstract

Stellar-aberration-based navigation requires angular measurements at the milliarcsecond (mas) level. While random sensor noise can be reduced by temporal integration, plate-solution uncertainty and residual geometric distortion may set a practical astrometric error floor. Here, we quantify the plate-model contribution to this error budget and examine its impact on the feasibility of stellar-aberration-based navigation. Using Gaia DR3 stars, HEALPix all-sky sampling, and covariance propagation to epoch J2026.0, we evaluate nine polynomial plate models while accounting for reference-star density and spatial distribution. We identify a bias–variance trade-off between model complexity, distortion-correction capability, and numerical stability. For the adopted ∼1° sparse-field configuration, the four-parameter linear model gives the lowest plate-constant variance, with a median of 0.95 mas and a 95th percentile of 1.7 mas. Using the first-order scaling of δv∼c δθ, this uncertainty corresponds to an approximate velocity-error scale of 0.9–2.5 m/s. These results show that plate-model errors can contribute at the meter-per-second level and must be included explicitly in StarNAV filter design.

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