MULTIPLE METHOD FOR DETECTING SUBSURFACE CONDUCTIVE OBJECTS Russian patent published in 2022 - IPC G01V3/11 

FIELD: testing.

SUBSTANCE: invention relates to the field of induction subsurface sensing and can be used for detecting and identifying subsurface conductive metal and metal-containing objects. Substance: a primary electromagnetic field is excited in the environment by means of an emitting frame antenna powered by a harmonic signal, wherein said field is used to induce eddy currents in the subsurface object, creating a secondary (re-emitted) electromagnetic field. The secondary electromagnetic field is recorded by means of a receiving ferrite magnetic antenna. Synchronised with the time parameters of the feeding harmonic signal, the EMF of induction induced in the receiving ferrite magnetic antenna by the secondary electromagnetic field is converted by the main measuring channel into in-phase and quadrature electrical signals. The impedance response of the emitting frame antenna caused by the electromagnetic properties of the subsurface object is recorded and converted simultaneously with the conversions of the main measuring channel by means of an additional measuring channel into an electrical signal of the additional measuring channel. The ratio between the signal of the main measuring channel U_OIC and the signal of the additional measuring channel U_DIC is defined as Δ=U_OIC/U_DIC. The values of said ratio are recorded, and when the value reaches the set threshold value Δ≥Δ_P, the mode of multiple amplification of the ferrite magnetic antenna and the process of algorithmic determination of the parameters of the subsurface object are initiated. The mode of initiated multiple amplification of the ferrite magnetic antenna is implemented by executing a separation filtration procedure, wherein the core of the receiving ferrite magnetic antenna is magnetised to the maximum value of the magnetic permeability thereof by supplying a constant scaled electrical signal to the coil of the ferrite magnetic antenna via an LF filter in the form of a throttle L. The induction EMF induced in the ferrite magnetic antenna by the secondary electromagnetic field is recorded via an HF filter in the form of a capacitor. The procedure of algorithmic processing of electrical signals of the measuring channels is implemented considering the sensitivity errors.

EFFECT: increase in the accuracy and sensitivity of the method for detecting concealed conductive objects.

2 cl, 7 dwg