Abstract:
The apparatus, typically a homing torpedo, includes an array of main directional sonar electroacoustic transducers, typically Tonpiltz oscillators, so distributed as to have directional response to signals and connected to generate commands to control the apparatus. The response pattern of this array alone has a main lobe and side lobes, the response to signals along the direction of the main lobe being substantially higher than to signals along the direction of the side lobe. An auxiliary predominately omnidirectional electroacoustic transducer (a hydrophone) is spaced of the order of one wavelength of the signal outwardly from a central main transducer and the combined response of this auxiliary transducer and central main transducer is compared to the total response from the array. If the combined response exceeds the total response, the control commands for the signals are suppressed and if the total response exceeds the combined response the control commands for the signals are enabled to control the apparatus. There is also apparatus including an array of main electroacoustic transducers and an auxiliary predominately omnidirectional electroacoustic transducer associated with, and spaced outwardly from, each main transducer. Each pair of main transducers and auxiliary transducers are so spaced and their response so combined as to suppress side lobes in the reception pattern of the apparatus.