Airborne gravimetry has become a vital technique in local gravity field approximation,and upward/downward continuation of gravity data is a key process of airborne gravimetry.In these procedures,the integral domain is divided into two parts,namely the near-zone and the far-zone.The far-zone contributions are approximated by the truncation coefficients and a global geo-potential model,and their values are controlled by several issues.This paper investigates the effects of flight height,the size of near-zone cap,and RemoveCompute-Restore(RCR) technique upon far-zone contributions.Results show that at mountainous area the far-zone contributions can be ignored when EIGEN-6C of 360 degree is removed from the gravity data,together with a near-zone cap of 1° and a flight height less than 10 km,while at flat area EIGEN-6C of 180 degree is feasible.
