Patent ID: 6778127
Filing Date: 2004-08-17
Classification: F41H,G01S,G01V

Abstract:
A drillstring radar system, comprising:an upward-looking radar antenna for mounting to a directional-drilling drillstring behind a steerable drillhead; a downward-looking radar antenna for mounting to said directional-drilling drillstring behind said steerable drillhead, a ground-penetrating radar transceiver connected to each of the upward-looking and downward-looking radar antennas, and providing for return signal attenuation and phase shift measurements, and for providing from said measurements real-time estimates of the distances transmitted radar signals traveled before being reflected back to a respective antennae; and a guidance control providing for steering said drillhead according to said real-time estimates; wherein, said real-time estimates are fetched from a calibration table that has in-phase (I) and quadrature-phase (Q) return-signal amplitude measurements as inputs.