Contemporary electronic surveying
Simo H. Laurila · Reviews of Geophysics · 1963
Electronic surveying—its feasibility, portability, and accuracy in geophysical mensurations—is analyzed. Geometries of various systems are presented, and circular, hyperbolic, and direct approaches are compared. Short derivations are made, and several phenomena of wave propagation are surveyed: shape of the ray path, velocity anomalies due to atmosphere and variable soil conductivity, reflections of long waves from the E layer and microwaves from the ground. The meaning of the use of various wavelengths in geophysical surveying is explained. An encyclopedic review is given of the different methods used in air to ground, ground to sea, and ground to ground surveying missions.