Presentation of the three examples

Introduction to passive underwater detection

Figure 1 - Position of the Hood sinking and the GIUK network

Figure 2 - Acoustic wave propagation diagram

Figure 3 - Xenakis wave glass

Figure 4 - Ruler for sonar range calculation

Figure 5 - General appearance of the PSD of stationary radiated noise

Figure 6 - Schematic evolution of the stepped pulse frequency

Figure 7 - Absorption coefficient as a function of frequency and temperature (S &#61; 35)

Figure 8 - Radii for a bilinear profile with local maximum

Figure 9 - Profile with a local minimum allowing a channel to appear

Figure 10 - Standard ambient noise level chart

Figure 11 - Antenna system on a typical submarine hull

Figure 12 - Front antenna of a Russian classic submarine at the shipyard

Figure 13 - Different types of passive antenna (except those shown in figure 11)

Figure 14 - Track formation by delay

Figure 15 - Weighting and directivity pattern of a linear antenna with 32 equidistant transducers

Figure 16 - Broadband detector (BL) and the ratio between the probability of detecting a source and that of a false alarm

Figure 17 - Waterfall broadband (BL)

Figure 18 - LOFAR example