| 摘要 |
<p>The invention concerns methods of resetting sonar images of the same ocean bed zone. It consists in the following steps: constructing, during a first impulse sequence, for each point F of the ocean bed, defined by its co-ordinates in sonar image no. 1, a secondary antenna of predetermined size at one end of the physical antenna, and with this secondary antenna, a first channel focused on F, over a short time slot centred on F; then in constructing a secondary antenna at impulse sequence no. 2, of the same size as the previous one, but at the opposite end of the physical antenna, and forming, with this second secondary antenna, a plurality of second channels on a sector sufficiently large for containing F; carrying out an intercorrelation of these second channels with the first channel so as to retain the one which maximises the correlation peak; finally repeating the previous operations for different sizes of secondary antennae and retaining the one which produces the maximum of the maxima of the previous intercorrelations. The best evaluation of position F in sonar image no. 2 is deduced from the offset in relative bearing between the first channel and the best second channel, from the delay of intercorrelation between these channels, and from the best size of secondary antenna. The method is then applied step by step. It ensures the coherent resetting of the successive images obtained with a sonar for all the impulse sequences of this sonar.</p> |
