An acoustic detection system for detecting targets that are at least partially submerged in a sensitive area defined relative to an infrastructure, the detection system comprising at least one multistatic detection group, each multistatic detection group defining a detection area, and comprising: • a submerged transmitter transmitting at low frequencies; • a plurality of submerged receivers comprising at least two receivers, characterised in that each receiver of a given group forms, with the transmitter of said group, a bistatic pair, each bistatic pair generating an elementary detection area surrounding a blind area , a blind area associated with a bistatic pair corresponding to a non-detection area, the detection area of said group being formed by all the elementary detection areas of said receivers of the group, the blind area of each receiver in a given detection group is at least partially covered by the elementary detection areas of the neighbouring receivers of the detection system, and in that the receivers of a given group describe at least one piecewise linear form, the receivers of a given group comprising at least one reference pair, said reference pair comprising receivers that are adjacent to and equidistant from the transmitter , the rectilinear segment linking the receivers of said reference pair being located at a distance D from the transmitter, called reference transmitter-receiver distance, the distance of a given receiver of the group relative to the axis of symmetry of the reference pair, from among the receivers of the group other than the receivers of the reference pair, depending on the reference transmitter-receiver distance D and on the distance (2 x 1 ) between the receivers of the reference pair. • a submerged transmitter transmitting at low frequencies; • a plurality of submerged receivers comprising at least two receivers, characterised in that each receiver of a given group forms, with the transmitter of said group, a bistatic pair, each bistatic pair generating an elementary detection area surrounding a blind area , a blind area associated with a bistatic pair corresponding to a non-detection area, the detection area of said group being formed by all the elementary detection areas of said receivers of the group, the blind area of each receiver in a given detection group is at least partially covered by the elementary detection areas of the neighbouring receivers of the detection system, and in that the receivers of a given group describe at least one piecewise linear form, the receivers of a given group comprising at least one reference pair, said reference pair comprising receivers that are adjacent to and equidistant from the transmitter , the rectilinear segment linking the receivers of said reference pair being located at a distance D from the transmitter, called reference transmitter-receiver distance, the distance of a given receiver of the group relative to the axis of symmetry of the reference pair, from among the receivers of the group other than the receivers of the reference pair, depending on the reference transmitter-receiver distance D and on the distance (2 x 1 ) between the receivers of the reference pair. <EOS>