Passive multipath target range and depth estimation using a variable depth sonar
AssigneeHughes Aircraft Company
InventorPaul L. Feintuch
Life of this patent
Estimating the term…
Abstract
A variable depth sonar is disclosed which is adapted to provide passive multipath target ranging and depth estimates. The sonar employs a novel estimation procedure which is adapted to sonars with relatively small sensors and limited computing power. A novel feature of the invention is the introduction of a change of depth of the sonar receiver, mounted on a mobile platform, into the estimation process. Measurements at the two different depths are combined to provide target range and depth. Other features and improvements are disclosed.
Claims11
A passive sonar system adapted to provide estimates of a target location, comprising:
- (a) receiver means adapted to receive acoustic energy from such target and provide receiver signal;
- (b) receiver positioning means adapted to move said receiver means from a first depth to a second depth;
- and
- (c) processing means coupled to said receiver means and adapted to process the receiver signals generated by said receiver at said first depth and at said second depth, and provide sonar signals indicative of the target's location.
A method of estimating target depth and range using a dual depth sonar, comprising the steps of:
- (a) positioning a sonar receiver at a first depth d.sub.1 ;
- (b) determining a first estimate .DELTA.(t.sub.1) of the difference in the acoustic energy propagation times for a direct propagation path and a surface reflected path at a first time t.sub.1 and at said first depth;
- (c) positioning the sonar receiver at a second depth d.sub.2 ;
- (d) determining a second estimate .DELTA.(t.sub.2) of said difference in propagation times at a second time t.sub.2 and at said second depth;
- (e) determining an estimate of the sonar receiver's velocity;
- and
- (f) calculating an estimate of the target's range from the sonar receiver, based upon said first and second estimates of the difference in propagation times, said estimate of sonar receiver velocity, and the time interval from said first time t.sub.1 said second time t.sub.2.
Dependencies are inferred from the claim text.