<p>A spacecraft equipped with a gravity gradiometer can provide direct, in situ measurements of a celestial body’s gravity field. However, accurate recovery of the gravity field from these measurements requires precise knowledge of the spacecraft’s position and attitude, as well as corrections for gradients induced by rotational motion. The impact of position and attitude errors becomes particularly critical during low-altitude operations or when using high-precision instruments. This study introduces a novel method, termed the <i>null-space mapping</i> (NSM), designed to mitigate the influence of position and attitude errors by projecting gradiometer measurements into a precomputed null space that removes their first-order effects. The applicability of the NSM to gravity field estimation in small-body missions is examined, and its relationship to conventional geodetic techniques for mitigating nuisance parameters is discussed. The method is further evaluated through numerical simulations of gravity field recovery around the asteroids Bennu and Eros. Simulation results demonstrate that the NSM effectively mitigates the impact of position and attitude errors on gravity field estimation. By reducing the dependency on highly precise orbit and attitude knowledge, the NSM enables the recovery of low-error gravity fields without explicitly correcting trajectory or attitude. This provides a computationally efficient framework for processing gradiometer measurements and supports autonomous gravity estimation capabilities for spacecraft operating near small celestial bodies.</p>