Patent ID: 8792300
Filing Date: 2014-07-29
Classification: G01V

Abstract:
1. A method for generating with a computing device a desired pilot signal for driving a vibratory source to generate seismic waves, the method comprising: selecting a pilot target amplitude spectrum for the vibratory source; determining an initial pilot signal that matches the pilot target amplitude spectrum; scaling the initial pilot signal to a force to be applied by the vibratory source to the ground, wherein the scaled pilot signal is in a force domain; level compressing the scaled pilot signal in the force domain to obtain a compressed pilot signal; determining a mass displacement associated with the vibratory source based on the compressed pilot signal; level compressing the mass displacement in a displacement domain to obtain a compressed mass displacement; and transforming the compressed mass displacement back to the force domain to obtain a modified pilot signal, wherein the level compressing of the mass displacement takes into account stroke limits of the vibratory source, the modified pilot signal boosts a low-frequency end of the vibratory source comparative to the initial pilot signal, the level compression in the force domain uses a first function and the level compression in the displacement domain uses a second function, and the first function is a sine function and the second function is where D i is a displacement, σdisp is a standard deviation of D i , δ is a scalar related to an output of the second function F and pwr is a coefficient related to a curvature at extremes of second function F.