Exploiting Full Flight Trajectories in Airborne Gravimetry: From Simulation to Real-World Validation

Airborne gravimetry plays a critical role in local gravity field determination but remains costly and operationally constrained. In current practice, gravity data collected during takeoff, landing, and turning (collectively referred to as preparing time) are routinely discarded due to sensor degradation under dynamic motion. These phases, however, constitute a substantial fraction of total flight time and represent a largely untapped data source. This study investigates the potential benefits of incorporating gravity observations from the entire flight trajectory to enhance local gravity field modeling.

Numerical simulations were first conducted to evaluate the impact of using full-flight gravity data under varying noise conditions and spectral bandwidths. Gravity disturbances synthesized from EGM2008 were downward continued using radial basis functions. Results show that including preparing-time data improves modeling precision by up to 67% within the spherical harmonic degree band [200, 1080] and up to 61% when extending the bandwidth to [200, 2160], consistently across different noise scenarios. The feasibility of this approach was further demonstrated using real scalar gravimeter data from the GRAV-D survey. Preliminary results of incorporating these recovered observations into an airborne-only local quasi-geoid model shows promising geoid model improvements when compared with GNSS/Leveling bench marks.

In addition to the completed work, ongoing research is exploring the integration of onboard inertial measurement unit (IMU) data, to which access has recently been obtained. Preliminary analyses reveal strongly correlated error patterns in the preparing-time gravity observations that appear closely linked to aircraft attitude variations. The availability of roll and pitch measurements from the IMU opens the possibility of analytically mitigating these errors through physical modeling, potentially reducing reliance on purely data-driven approaches.

Additional simulations indicate that achieving 1 mGal-level gravity precision during dynamic flight requires roll and pitch angle accuracies better than 5 arc-minutes, underscoring the importance of accurate attitude information. Overall, the results highlight significant untapped potential in airborne gravimetry and suggest a paradigm shift toward exploiting full flight trajectories. As emerging technologies such as vector gravimetry, cold-atom sensors, and advanced inertial systems continue to mature, the systematic integration of dynamic-flight data is expected to further enhance the accuracy and efficiency of future airborne gravity surveys.