Method and system for depth sounding
AssigneeCanadian Astronautics Limited
InventorPhilippe de Heering
Life of this patent
Estimating the term…
Abstract
A method and apparatus for the sounding of waters, particularly suitable for depth (and the like) sounding of Arctic waters, comprises shooting an energetic projectile at the water or ice surface from, say, a helicopter which has suspended close to the waters surface a suitably housed microphone for receiving the echo energizing from the waters. By measuring elapsed time between firing of the projectile and reception of the echo, and knowing all distances except the depth of the reflecting boundary (be it the bottom or a submarine), the unknown depth is easily determined.
Claims11
An echo sounding method for determining the depth of a boundary under the surface of a body of water even if the water is covered by ice or by ice and snow, comprising the steps of:
- (a) impacting the upper surface of the body of water or the upper surface of the ice if the water is covered by ice or by ice and snow with a bullet-type projectile so as to generate an impact sound impulse at the upper surface of the water or the upper surface of the ice, if ice or ice and snow covers the water;
- (b) detecting in the air and at a predetermined distance above the upper surface of the body of water, an echo of the sound impulse reflected by said boundary;
- (c) measuring time elapsed between the sound impulse and the echo at said predetermined distance;
- and
- (d) determining the depth under the upper surface of the water with respect to said boundary from the elapsed time, the predetermined distance, the known thickness, if any, of any covering ice or ice and snow, and known sound velocities in the body of water and in the air.
A system for echo sounding of a body of water even if the water is covered by ice or by ice and snow comprising;
- a. means for impacting the upper surface of the body of water or the upper surface of the ice if the water is covered by ice or by ice and snow with an energetic, bullet-type projectile so as to generate an impact sound impulse;
- and
- b. detection means for detecting in the air an echo of the impact sound impulse of said bullet-type projectile at a predetermined distance above the upper surface of the body of water;
- and
- c. means for determining elapsed time between impact of said bullet-type projectile with said surface and detection of said echo;
- and
- d. means for determining the depth under the upper surface of the water with respect to a boundary under the body of water from the elapsed time, the predetermined distance, the known thickness, of any covering ice or ice and snow, and known sound velocities in the body of water and in the air, and if present, in the ice.
A system for echo sounding of a body of water even if the water is covered by ice or by ice and snow comprising;
- a. means for impacting the upper surface of the body of water or the upper surface of the ice if the water is covered by ice or by ice and snow with a rifle bullet, so as to generate an impact sound impulse;
- and
- b. detection means for detecting in the air an echo of the impact sound impulse of said rifle bullet at a predetermined distance above the upper surface of the body of water;
- and
- c. a helicopter for firing the rifle bullet;
- and
- d. means for determining the depth under the upper surface of the water with respect to a boundary under the body of water from an elapsed time between impact of the rifle bullet with said surface and detection of said echo, the predetermined distance, the known thickness of any covering ice or ice and snow, and known sound velocities in the body of water and in the air and if present in the ice.
A system for echo sounding of a body of water even if the water is covered by ice or by ice and snow comprising;
- a. means for impacting the upper surface of the body of water or the upper surface of the ice if the water is covered by ice or by ice and snow with an energetic, bullet-type projectile so as to generate an impact sound impulse;
- and
- b. detection means for detecting in the air an echo of the impact sound impulse of said bullet-type projectile at a predetermined distance above the upper surface of the body of water;
- and
- c. means for determining elapsed time between impact of said bullet-type projectile with said surface and detection of said echo;
- and
- d. a device forward of the detection means for firing the bullet-type projectile from a moving craft;
- and wherein the detection means is an echo detector which is focussed downwardly and which comprises a first microphone for measuring noise generated by the moving craft and a second microphone for detecting the echo and wherein an electronic signal processing means includes means for subtracting an attenuated version of the craft noise generated by the moving craft from the echo so as to increase the signal to noise ratio of the echo.
Dependencies are inferred from the claim text.