METHOD OF DETERMINING HEADING ANGLE TO RADIATION SOURCE FROM MOBILE SUBSURFACE OBJECT AND DEVICE FOR REALISING SAID METHOD Russian patent published in 2010 - IPC G01S3/80 

FIELD: physics.

SUBSTANCE: method involves generation and emission from a source of a harmonic signal with frequency ω, reception of an acoustic signal using a set of N≥8 hydrophones which form a circular measuring base directed into the horizontal plane, picking up quadrature components of the complex envelope of received acoustic signals, measurement of the phase of acoustic signals, preliminary phasing of the measuring base into N directions passing through the centre of the measuring base and each of the N hydrophones, determination of the direction which corresponds to the maximum of the signal and a hydrophone lying in that direction, calculation of the heading angle to the source in a local coordinate system associated with the measuring base using corresponding formulas. The hydrophone lying in the direction of the signal maximum is taken as the first hydrophone. The mobile subsurface object is also fitted with a pair of hydrophones spaced out in a diametrical plane along the mobile subsurface object at a distance of 1≤λ/4σ_θ. After calculating the bearing, the heading angle β₀ to the source is calculated using formula β₀=β₁±θ₀, σ_β0=σ_β, where β₁ is the heading angle of the first hydrophone of the circular measuring base, the sign (+) is taken for the heading angle of the starboard side, the sign (-) is taken for the heading angle of the port side, σ_β0 is the error in determining the heading angle, σ_θ is the bearing measurement error. The mobile subsurface object then synthesises a beam path on which the condition β₀=180°+σ_θ is satisified, and a traversing path on which the condition β₀=±90°+σ_θ is satisfied. Further, phase difference of acoustic signals Fm received using an extra pair of hydrophones is measured on the traversing path at time moments t_m, m=1-M. The values of phase difference of acoustic signals F_m(t_m) measured on the acoustic path are approximated with a linear function F=a(t-t₀). Parametres a are determined through a least-squares method using corresponding formulas, and the true heading angle to the source at point t=t₀ is determined using formula

EFFECT: reduced error in measuring heading angle at low frequencies without increase in overall dimensions of the direction finder.

2 cl, 3 dwg