Research On The Passive Bearing Problem Of Noise Target

Active SONAR provides signal for enemy when ranging by transmitting pulse and this is very dangerous for submarine. Therefore, Passive SONAR, aiming at universal noise targets, becomes the dominating SONAR of submarine. The traditional SONARs are consisted of middle or small scale Integrated circuit. Their hardware is big and low calculation ability. So the position precision of the SORNAR is low and the ability of tracing target is limited. It is necessary to improve the ability of the traditional SONARs using digital signal processing and electronic technology. The system will be integrated, digital and miniaturization. The calculation ability and precision of SONAR will be improved.The direction model is an important part of passive SONAR. It can detect target in 360° ranging and can tracing multi targets (three) in the same time. It can provide direction data to other models. The paper is on improving the direction model of Passive SONAR.First the paper explains the principle and physical basement of passive SONAR direction and the reason that will lower the precision. The paper provide a completed method of direction—passive cross-correlate direction and its CRLB. Second, the paper introduces all parts of passive noise direction: including pre-processor, beam forming, generalized cross-correlator (GCC), ranging time delay estimator, and post-filter, etc. Emulate beam forming and slide windows correlating. Compare of the new and the old methods, performance is detail analyzed. Last, the paper introduces the design of direction model of passive SONAR including digital filter, advantaged slide windows cross-correlator correlation and tracer. The program is optimized to fit the needs of real-time processing.The design of passive noise direction model in the paper has been realized on DSP and passed the examination of SONAR emulator. The performance reaches the request of the system. At last, the paper provides the result of moving targets. The result proves that the precision of the direction model is better.