THEORETICAL ANALYSIS OF THE APPLICATION OF PSEUDO-NOISE SIGNALS IN MARINE PULSE ELECTROMAGNETIC PROSPECTING

Abstract

Using numerical modeling of a useful signal based on a characteristic geoelectric model of underwater permafrost and real recordings of a noise signal, we conducted a comparative analysis of noise suppression during transient sounding using a marine towed dipole-dipole array in accumulation modes with opposite-polar current pulses and pseudo-noise signals (PNS). For a series of current sequences in the form of PNS with different durations and numbers of pulses, as well as for a signal in the accumulation mode, with the superposition of an identical noise signal, transient sounding curves were obtained corresponding to the geoelectric model under consideration at a recording time of the order of 8-13 s per station. Based on the results of comparison of the obtained curves reconstructed from noisy synthetic data in the accumulation and PNS modes, it was established that in the PNS mode with pulses of duration 100 μs and 1 ms, the relative error in the PNS mode on average over the profile turns out to be significantly lower (up to 1.5 times) than a similar one error in the accumulation mode, and remains within an acceptable value (up to several percent) until later times.