MEASUREMENT OF SONAR RANGE EMPLOYING GRAPHIC INDICATOR METHODS
Abstract
The Sonar Graphic lndicator in conjunction with a standard echo-ranging sonar provides range rate by doppler measurements. It also provides discernible discrimination because of phase coherence or doppler difference between the hull echo of the target and reverberation or wake return. To utilize these features for more accurate sonar range measurements, an experimental equipment has been constructed. This equipment consists of a Graphic Indicator with strip display and a range unit providing digital range indication and rate-aided range tracking, The range unit consists of an electronic chronometer which measures the time interval between the projected sonar pulse and the appearance of an electronic range cursor which can be positioned in coincidence with the hull echo in the strip display. Range rate obtained from the Graphic Indicator is utilized to give rate-aided tracking by automatically positioning the cursor. Evaluation tests of the experimental equipment were conducted using a destroyer and target submarine. The vessels participated in a series of maneuvers designed to present the target at all aspects for a number of combinations of speed, depth, range, range rate, and range acceleration. Approximately 100,000 items of data including range, range rate, bearing, ship's speed, aspect, and other variables were photographically recorded. Data obtained from these tests yielded information as to the accuracy of range measurements by the Sonar Graphic Indicator method, and produces evidence leading to a better understanding of a submarine as a sound reflector. Analysis of data indicated the experimental equipment capable of measuring range with an average error of less than one yard and an rms error of approximately 12 yards. It was also observed that rate-aided tracking considerably enhanced the operator's ability to track the target in range.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1955
- Accession Number
- AD0083199
Entities
People
- Burton G. Hurdle
- Kinglsey P Thompson
- Raymond H. Ferris
- Robert J. Mackey Jr
Organizations
- United States Naval Research Laboratory