Evaluate the Performance of Underwater Target Detection System in Forward Scattering Zone

The bistatic sonar can´t detect the target nearby the baseline because of the effect of direct wave. The forward target strength is 15 dB above the other direction according to the Babinet´s principle. This phenomenon could be utilized for target detection. The three key points including forward target strength, sonar coverage and system response time are discussed. The derivation of the forward target strength from the Babinet´s principle is given. The result is consistent with the analytic solution for finite length cylinder. From the point of system design, the forward scattering sonar equation is given, the detection system coverage is evaluated. Further, the system response time using field fluctuation for slow moving target detection is analyzed.