Leveling airborne and surface gravity surveys

For both airborne gravimetric and airborne magnetic surveys, systematic residual errors usually remain in the data after standard data processing. In the literature, the mismatches at the crossover points are used to either adjust the processing procedures or directly adjust the results. This is usually called crossover adjustment. Due to the limited crossover points, it has a risk of leaking the random errors into a systematic distortion of the entire data. In aeromagnetic surveys, the low-wavenumber information is used to construct a smooth field to level the survey data without the need for tie lines. However, this method relies on the long-wavelength component of the flight line data accurately sampling the regional field. Here, an alternative approach is developed to model the physical field using radial basis functions (RBF) and to parameterize the systematic errors at the same time, which avoids all of the aforementioned problems. Numerical results show that the new method provides more stable results than the classical approach. The method is also tested on terrestrial gravity surveys (where it is challenging to directly apply the crossover analysis). Here also, it yields promising results.