Robert D Mcfarland

US Patent:

39394638, Feb 17, 1976

Filed:

Feb 5, 1964

Appl. No.:

4/342833

Inventors:

Neil C. Kelly - San Diego CA
Robert L. McFarland - San Diego CA
Jack W. Sampsell - National City CA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01S 968

US Classification:

340 3E

Abstract:

1. In combination in an acoustic obstacle detection and navigating system; A transmitting station comprising a variable frequency oscillator, a sawth generator coupled to said oscillator for sweeping the frequency of oscillations through the range of frequencies from f. sub. 1 to f. sub. 2, a submersible projection transducer coupled to said oscillator for continuously ensonifying a sector of water about said transducer with sonic energy varying between f. sub. 1 and f. sub. 2, A fixed frequency oscillator of frequency f. sub. 3 at said station, A sonar receiver at said station including a mixer for combining the frequencies f. sub. 1 to f. sub. 2 of said oscillator with the echo frequencies reflected from a passive target, so that the difference at any instant between the reflected frequency and the transmitted frequency is a frequency proportional to the rate of change of said variable frequency and target range, A remote transponder station including a receiving hydrophone coupled to a transmitting transducer, a mixer coupled between said hydrophone and transmitting transducer, a local oscillator of fixed frequency, f. sub. 3, coupled to said mixer for shifting received frequencies from the range of f. sub. 1 to f. sub. 2, to the range of f. sub. 1 + f. sub. 3 to f. sub. 2 + f. sub.