Wireless Control Mechanism for EM Source and Receiver Positioning for Offshore Application

Abstract

This study proposes a prototype on wireless control mechanism for better positioning of Electromagnetic (EM) source with receiver for offshore sea bed logging application. In sea bed logging array of receivers are placed on the sea bed to record signal that comes from the transmitter that is towed 20-40 m above the sea bed. When a receiver is dropped on the sea bed, it will end up in arbitrary direction, which means that the recorded electric and magnetic x- and y-components will also point in arbitrary directions. This will affect the quality of the received signals. The amplitudes of electric and magnetic marine Controlled Source Electromagnetic (CSEM) data are highly offset dependent. In the present technique the measurement of the receiver orientation can be performed using gyroscope and compass. The retrieved data have to be corrected using rotation equations to obtain the inline rotation angle (0°) before the amplitude of the horizontal electric and magnetic fields can be obtained. Our work premise focuses on using wireless control mechanism to correct or reposition the EM receiver so that it is inline with the transmitter position. A computer that acts as a controller station will be used to monitor the position of the EM detector using Zig-Bee wireless communication on real time basis. A robot is constructed to hold the EM receiver and this robot shall be turn clockwise or anti clockwise to ensure the correct positioning of the EM source to the receiver. By using this mechanism we shall demonstrate the improved in receiving signals in term of amplitude as we reposition the receiver to be inline with the transmitter (0°). © 2011 Asian Network for Scientific Information.