Acoustic log

US3991398A · kind A · utility

Assignee

• Jungner Instrument AB

Inventors

• Nils Ingvar Andermo · Kirkland, US
• Karl G. Masreliez · Stockholm, SE

Key dates

• Filing date: May 28, 1974
• Grant date: Nov 9, 1976
• Expiry date: May 28, 1994

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S15/60
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Apparatus for measuring a vessel's velocity relative to a reference location includes a transmitter on board the vessel for transmitting a coherent signal toward a reference location from where the coherent signal is reflected, and a receiver on board the vessel which includes at least two spaced-apart receiver transducers. The coherent signal transmitted by the transmitter is within a lobe range that is substantially common to the at least two receiver transducers, the signals reflected by the reference location comprising at least two acoustic signals that are similar in character but different in timing from each other, the difference in timing being a function of the distance in the direction of measurement between the spaced-apart receiver transducers and further being a function of the vessel's velocity, the received signals comprising reflections from every point on the reference location within the lobe range. Operating means is provided to operate on the reflected acoustic signals received by the receiver so as to generate a signal which is a function of the timing difference between the two signals and which is further indicative of the vessel's velocity relative to the r…