US 4,225,949 A · Method of and apparatus for navigating unmarked channels

Abstract

In an apparatus for guiding or controlling a vessel over the center of an unmarked channel, a pair of ultrasonic transducers are mounted athwartship on the hull of the vessel and directed downwardly to transmit ultrasonic pulses and to receive corresponding pulses reflected from the floor of the body of water. Time durations between transmitted and corresponding received pulses are measured to determine floor or channel depth below the port and starboard sides of the vessel. The depths are digitally encoded and supplied to a comparator which generates a signal indicating whether deeper water is port or starboard of the vessel. The comparator signal is supplied to a display to instruct the navigator whether to steer port, starboard or to maintain course to guide the vessel over the center of the channel. The comparator signal may be also supplied to a rudder servo to automatically steer over the channel center. A digital filter is provided to eliminate any spurious readings obtained by the transducers.

Claims20

Dependent claims

A navigational apparatus for guiding a vessel above the deepest part of a channel, comprising:

first and second transducer means mounted athwartship and equally spaced from the center of said vessel;
means for operating said first and second transducer means to transmit energy pulses downwardly through the water to be reflected from the channel bottom;
means for operating said first and second transducer means to receive the reflected energy pulses;
means for filtering spurious signals received by said first and second transducer means;
means for measuring a time duration between transmission of pulses and reception of corresponding, reflected pulses at each one of said transducers and for generating first and second electrical signals indicative respectively of channel depths on opposite sides of said vessel;
means for comparing said first and second electrical signals;
means for displaying a port, starboard or maintain course steering command;
and
means responsive to said comparing means for controlling said display means as a function of channel depth to display one of said steering commands depending upon the location of the deepest part of the channel relative to said vessel to enable guiding of said vessel above the deepest part of said channel.

6 more elements

Dependencies are inferred from the claim text.

Method of and apparatus for navigating unmarked channels

Life of this patent

Method of and apparatus for navigating unmarked channels

Life of this patent

Abstract

Claims20