PHASE PARAMETRIC SIDE-LOOKING SONAR SYSTEM Russian patent published in 1995 - IPC

FIELD: underwater acoustic investigations. SUBSTANCE: phase parametric side-looking sonar system is meant for increased authenticity of detection and recognition of silted objects, bottom and close to bottom objects thanks to use of additional information on acoustic "stiffness" of objects by measurement of phase invariance of biharmonic signals with pulse amplitude modulation. Side-looking sonar system has transmitter and transmitting-receiving antenna connected in series, controlled HF amplifier, selector, unit of discrimination of target and shadow coupled in series as well as synchronizer, register, extent, parallelism and rectilinearity units, decision-making unit. Inputs of extent, parallelism and rectilinearity units are connected to output of selector and their outputs-correspondingly to first, second and third inputs of decision-making unit which output is linked to second input of register. Output of controlled LF amplifier is connected to its first input. Second output of transmitter is coupled to input of synchronizer which first output is linked to first controlling input of transmitter and which second output is connected to input of controlled HF amplifier. Sonar system is supplemented with decouplers, receiving antenna, controlled amplifier of difference frequencies, first and second selective amplifiers of difference frequencies, phase inverter phase discriminator and indicator. Decoupler is placed in series between transmitting-receiving antenna and controlled HF amplifier. LF receiving antenna is connected to input of controlled amplifier of difference frequencies which first controlling input is linked to second output of synchronizer and its second input to inputs of first and second selective amplifiers of difference frequencies as well as to first input of indicator. Outputs of first and second selective amplifiers of difference frequencies are connected correspondingly through frequency doubler and phase inverter to first and second inputs phase discriminator which output is coupled to second input of indicator. Controlling input of indicator is linked to first output of synchronizer, third output of the latter is connected to second controlling input of transmitter. EFFECT: increased authenticity of detection and recognition of silted objects. 4 cl, 7 dwg