Patent ID: 9170346
Filing Date: 2015-10-27
Classification: B63B,G01V

Abstract:
1. A buoy for recording seismic signals while underwater, the buoy comprising: a body; a buoyancy system configured to control a buoyancy of the body to descend multiple times to at least one predetermined depth (H) and then resurface with a controlled speed; a seismic sensor located on the body and configured to record the seismic signals; a processor configured to instruct the seismic sensor to record the seismic signals at a predetermined time interval; an inertial device configured to determine a relative displacement of the buoy between consecutive recordings; a timing device configured to provide an accurate time such that the recorded seismic signals are associated with a corresponding time and a corresponding relative displacement; and a global positioning system configured to determine initial and final water surface absolute locations of the buoy, wherein the initial water surface absolute location of the buoy is measured by the global positioning system prior to descending to the at least one predetermined depth (H), and the final water surface absolute location is measured by the global positioning system after the buoy resurfaces, wherein the processor is configured to calculate absolute positions for each time when the seismic signals are recorded, based on the relative displacement from the inertial device, the accurate time from the timing device and the initial and final water surface absolute locations of the buoy, and wherein the seismic sensor is instructed to record the seismic signals as the buoy travels up and down between the water surface and the predetermined depth.