Design, calibration and evaluation of a two axis correlation log for use on autonomous underwater vehicle

The design of a specific correlation speed log system developed to meet the requirements for relatively low-cost, high-performance submersible mounted operation is presented. The installation calibration of high-performance speed logs on surface vessels is important in order to identify and minimize the effects of installation misalignments. The hardware and procedures used to reduce the amount of trials time required to complete this task are described. The innovative features include the use of a rotating transducer platform to optimize the polar speed measurement process, and the combination of an acoustic log with an electromagnetic system to provide continuous high-integrity speed data. A number of aspects of the operation, design, and calibration of correlation logs are discussed