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Experiments conducted with the first DPG model in the large 

 wave tank at the Coastal Engineering Research Center were plagued by 

 highly non-linear waves and the failure of three differential 

 pressure channels. However, results from the absolute pressure gauge 

 and one differential pressure gauge indicated the ability of the DPG 

 to estimate wave height, period, and direction. The tests were also 

 valuable in defining several important modifications required to 

 improve the performance of the DPG system. 



Measurements of the orientation of the instrument were 

 discussed and the importance of careful consideration of compass 

 readings in the vicinity of steel structure was stressed. Although 

 it initially appeared that diving compasses were placed upon the 

 instrument sufficiently far from the steel cradle to avoid its 

 magnetic effects, redundant measurements of the instrument 

 orientation indicated that the compass readings were biased. The 

 error was resolved using a simple technique outlined in the thesis. 

 It was suggested that measurements from simple wrist compasses, when 

 taken and interpreted carefully, may be adequate in determining 

 instrument orientation. 



The DPG utilizes four differential pressure gauges placed to 

 the bow, port, stern, and starboard of an absolute pressure gauge 

 such that there are two adjacent differential gauges along each of 

 two perpendicular axes. The DPG system develops the first five 

 directional Fourier coefficients using signals from the absolute 



