Hybrid correlation and EM ships speed log

The author discusses the development of a tool for the evaluation of the correlation method of speed measurement. The system developed has a transducer with 31 individual elements each of which would be used as a transmitter and/or receiver. The elements are arranged in two groups; one of sixteen arranged as a four by four matrix, the second group is arranged as two orthogonal lines of eight elements with a common element one element down from the lead element in each line. Within the acoustic transducer, a two axis electromagnetic log is incorporated. The hybrid correlation/EM speed measurement system has demonstrated the feasibility of providing high integrity ground speed measurement data in water depths greatly exceeding those normally associated with other methods of making such measurements