METHOD FOR DETERMINATION OF DIRECTION TO THE SOURCE OF HYDROACOUSTIC SIGNAL (MODIFICATIONS) Russian patent published in 2003 - IPC

FIELD: underwater acoustics associated with reception of wide-band signals, applicable in hydrophoning, sonar direction finding, detection of hydroacoustic signals, classifying, underwater communication, for underwater geophysical operations. SUBSTANCE: two modifications of the method are claimed. According to the first modification of the method, which includes the reception of signal from the direction of the main maximum of the directional pattern of the multiwire equidistant antenna, the signals are received within frequency band where c - sound velocity, d - distance between the wires, θ-current angle, θ₀-compensation angle. Within this frequency band one more or several maxima symmetrically positioned relative to the main additional maximum are formed in the directional pattern. The reception frequency is changed up to variation of the angular distances between the main and each of the additional maxima by an angle not less than the angular width of the additional maximum in a level of 3 dB. If the signal is received, the direction of signal input is determined as the direction of the additional maximum. For defining more exactly the direction in the presence of two additional maxima at the varied frequency of reception the directional pattern is turned until one of the additional maxima coincides with the initial one. At fixing of the signal this direction is determined as the direction of signal input from the source, and in its absence - as the direction of the other additional maximum at the initial frequency of reception. According to the second modification of the method, reception is accomplished simultaneously at two different frequencies f_a, f_b, in this case each of frequencies f_a, f_b satisfies condition (1). If the signal is received at both frequencies, the direction of signal input is determined as the direction of the main maximum, if at one of the frequencies - as the direction of the additional maximum at the given first frequency. For defining more exactly the direction in the presence of two additional maxima the directional pattern is turned at the second frequency until one of the additional maxima coincides with the direction of the additional maximum at the first frequency, where the signal is received. At the reception of the signal at the second frequency this direction is determined as the direction of signal input from the source, and in the absence - as the direction of the other additional maximum at the first frequency. EFFECT: expanded frequency band in the range of which the direction to the signal source is determined unambiguously at similar wave dimensions between the antenna wires, enhanced accuracy of direction finding, reduced number of active antenna wires, quantity of channels, cost at the same wave dimension of the antenna. 2 cl, 4 dwg