Acoustic Streamer Tracking - Ast 030

Following the introduction of 3-D offshore seismographic surveys, there is a need for more accurate positioning of the signal source (guns) and the seismic streamer cables.We also see a development towards more complex survey schemes.A large number of ranges (and/or bearings) is needed to describe ' the towed system satisfactory.A typical performance of a positioning system could be in the order of 100 updates within every 10 seconds.Bentech Subsea has developed a short baseline positioning system meeting the above requirements.A high degree of accuracy in the position estimates is obtained by using digital correlation techniques both for range and bearing calculations.The bearing calculation is performed by the SCOT algorithm involving FFT, whitening and IFT.'The time consuming steps in the calculations are run on a DSP single board processor developed by Bentech Subsea.The DSP processor is based on a Motorola M56000 chip.The system has been run under normal seismic operation, and examples of the results are given.