An interwell tomography method for guided drilling, the method comprising: casing a first borehole with a casing tubular lining a wall of the first bore hole and having at least one transmission crossover arrangement , each transmission crossover arrangement having an internal adapter in communication with an external coil antenna that encircles an exterior of the casing tubular; deploying, inside the casing tubular, a conductive path that extends from a surface interface to the at least one transmission crossover arrangement , wherein the adapter enables coupling of the transmission crossover arrangement to the conductive path ; drilling a second borehole with a steerable drillstring having antennas to transmit or receive signals from the at least one transmission crossover arrangement of the first bore hole; acquiring measurements of the antenna responses to signals received at the steerable drillstring from the at least one transmission crossover arrangement of the first bore hole; processing the acquired measurements to improve the signal-to-noise ratio of the measurements; inverting the acquired measurements to match the measurements with synthetic measurements from a tomographic formation model to derive model parameter values; displaying a representation of the derived model parameters ; determining a position of the steerable drillstring by triangulation using distance or direction measurements acquired from the antenna responses and deriving, in combination with previous measurements , a trajectory of the steerable drillstring; and steering the steerable drillstring along a course relative to the first bore hole in response to the determined position and derived trajectory. casing a first borehole with a casing tubular lining a wall of the first bore hole and having at least one transmission crossover arrangement , each transmission crossover arrangement having an internal adapter in communication with an external coil antenna that encircles an exterior of the casing tubular; deploying, inside the casing tubular, a conductive path that extends from a surface interface to the at least one transmission crossover arrangement , wherein the adapter enables coupling of the transmission crossover arrangement to the conductive path ; drilling a second borehole with a steerable drillstring having antennas to transmit or receive signals from the at least one transmission crossover arrangement of the first bore hole; acquiring measurements of the antenna responses to signals received at the steerable drillstring from the at least one transmission crossover arrangement of the first bore hole; processing the acquired measurements to improve the signal-to-noise ratio of the measurements; inverting the acquired measurements to match the measurements with synthetic measurements from a tomographic formation model to derive model parameter values; displaying a representation of the derived model parameters ; determining a position of the steerable drillstring by triangulation using distance or direction measurements acquired from the antenna responses and deriving, in combination with previous measurements , a trajectory of the steerable drillstring; and steering the steerable drillstring along a course relative to the first bore hole in response to the determined position and derived trajectory. <EOS>