G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
G01V3/02—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with propagation of electric current
G01V3/04—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with propagation of electric current using DC
G—PHYSICS
G01—MEASURING; TESTING
G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
G01R27/16—Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line
G01R27/18—Measuring resistance to earth, i.e. line to ground