Patent ID: 8773950

Claim:
A method for seismic prospecting, the method comprising: deploying plural vibratory sources on the ground; receiving at each vibratory source a corresponding pilot signal (A) for driving the vibratory source; asynchronously actuating the vibratory sources to generate seismic waves into the ground; and continuously recording seismic signals produced by the seismic waves, wherein the step of asynchronously actuating includes, accessing an accurate time; calculating a sweep index pointer; accessing a corresponding start point in the pilot signal; actuating the source from the corresponding start point; proceeding through the pilot signal from the corresponding start point to a final point of the pilot signal; and continuing to proceed through a beginning of the pilot signal for a predetermined sweep length, and wherein pilot signals (A-D) for the plural vibratory sources are obtained by spectrally shaping starting sequences into continuous pseudorandom sequences that are weakly correlated over a predetermined time interval.