Patent ID: 7599253

Claim:
A towed or a line array of acoustic sensors for use with an underwater vehicle comprising: a linear array of n acoustic pressure sensor elements; an acoustic vector sensor element located at the acoustic center of the linear array of n acoustic pressure sensor elements; wherein the linear array of n acoustic pressure sensor elements generates a beam pattern based on the equation: D 1 ⁢ ⁢ ( θ , φ ) = {  ∑ j = - ( n - 1 ) ⁢ / ⁢ 2 ( n - 1 ) ⁢ / ⁢ 2 ⁢ ⁢ A j ⁢ ⁢ exp ⁡ [ ⅈ ⁢ ⁢ 2 ⁢ ⁢ π λ ⁢ ⁢ ( j ⁢ ⁢ d ) ⁢ ⁢ cos ⁢ ⁢ θ ⁢ ⁢ cos ⁢ ⁢ φ ] p max ⁢ ⁢ ( θ , φ )   sin ⁢ ⁢ ( n ⁢ ⁢ π ⁢ ⁢ d λ ⁢ ⁢ cos ⁢ ⁢ θ ⁢ ⁢ cos ⁢ ⁢ φ ) n ⁢ ⁢ sin ⁢ ⁢ ( π ⁢ ⁢ d λ ⁢ ⁢ cos ⁢ ⁢ θ ⁢ ⁢ cos ⁢ ⁢ φ )  ⁢ ⁢ A L = A M , L , M = - ( n - 1 ) ⁢ / ⁢ 2 , - ( n - 1 ) ⁢ / ⁢ 2 + 1 , … ⁢ ⁢ ( n - 1 ) ⁢ / ⁢ 2 where θ is the angle of bearing, φ is the angle of depression and elevation, n is the number of acoustic pressure sensors, d is the distance between the sensors and λ is the wavelength of the sound wave; wherein the acoustic vector sensor element generates a beam pattern based on the equation: D 2 (θ,φ)=| w 0 p+w x cos θ cos φ+ w y sin θ cos φ+ w z sin φ| where w 0 , w x , w y , and w z are weighting coefficients to the hydrophone x-, y-, and z-axial vector sensor signal output; and wherein a multiplication operation in signal processing for the n acoustic pressure sensors and the acoustic vector sensor generates a beam pattern based on the following hybrid equation: D 1 ⁢ ⁢ ( θ , φ ) · D 2 ⁢ ⁢ ( θ , φ ) =  ∑ j = - ( n - 1 ) ⁢ / ⁢ 2 ( n - 1 ) ⁢ / ⁢ 2 ⁢ ⁢ A j ⁢ ⁢ exp ⁡ [ ⅈ ⁢ ⁢ 2 ⁢ ⁢ π λ ⁢ ⁢ ( j ⁢ ⁢ d ) ⁢ ⁢ cos ⁢ ⁢ θ ⁢ ⁢ cos ⁢ ⁢ φ ] p max ⁢ ⁢ ( θ , φ )  ·  w 0 ⁢ ⁢ p + w x ⁢ ⁢ cos ⁢ ⁢ θ ⁢ ⁢ cos ⁢ ⁢ φ + w y ⁢ ⁢ sin ⁢ ⁢ θ ⁢ ⁢ cos ⁢ ⁢ φ + w z ⁢ ⁢ sin ⁢ ⁢ φ  ; and wherein based on said hybrid equation a sonar system can resolve the left-right ambiguity for said linear array of n acoustic pressure sensor elements; and the hybrid towed array directivity D(θ,φ)=D 1 (θ,φ)·D 2 (θ,φ) is rotate able in all directions.