Liquid impoundment survey vehicle incorporating positioning finding and tracking system
AssigneeSouthwest Research Institute
InventorThomas E. Owen
Life of this patent
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Abstract
In a geomembrane defined impoundment, a leak is located by vessel supported means. The present invention is directed to locating the vessel so as to then locate the leak. A set of N hydrophones spaced around the impoundment detect a liquid transmitted acoustic pulse from the vessel. The vessel supports an RF transmitter which broadcasts a timing pulse. With the timing pulse, elapsed acoustic travel time is measured to define range in the liquid. The range defines an arc of a circle around a single hydrophone. Using N hydrophones, N arcs are defined on the impoundment, each centered on the respective hydrophones, to intersect at the vessel location.
Claims13
For use with a vessel traveling across liquid in an impoundment confined within a geomembrane wherein the vessel carries leak detecting apparatus to locate leaks in the geomembrane, a position determining system which comprises:
- (a) at least three hydrophones located around the periphery of the liquid impoundement adapted to receive sound transmissions through the liquid impoundment;
- (b) acoustic transmitter means on the vessel for emitting periodic acoustic pulses into the impounded liquid for reception by said hydrophones;
- (c) timing means for providing a measure of elapsed travel time from the acoustic transmitter on the vessel to the respective hydrophones, said timing means providing the elapsed time as a function of travel through the impounded liquid;
- and
- (d) calculating means for determining as a function of the elapsed travel time determined by said timing means, said calculating means determining the range from said hydrophones to said acoustic transmitter and further determining the location of the vessel on the impoundment as a function of range, said calculating means being independent of the value of the velocity of sound in said liquid.
A method for determining the location of a leak in a geomembrane defining a liquid impoundment, the method comprising the steps of:
- (a) measuring the transmission time of an acoustic pulse from a vessel traversing the liquid impoundment with a supporting leak detecting means to thereby obtain indications of leaks in the geomembrane;
- (b) determining the position of the vessel as it traverses the liquid impoundment as a function of time independent of the velocity of said acoustic pulse through said liquid;
- and
- (c) coordinating the determination of a leak in the geomembrane with the plotted location of the vessel to thereby determine the location of the leak.
Dependencies are inferred from the claim text.