Two kinds of passive ranging algorithms are proposed combined with waveguide invariant theory based on the important characteristic of the ocean waveguide that the inter- ference structure is stable and can be observe...Two kinds of passive ranging algorithms are proposed combined with waveguide invariant theory based on the important characteristic of the ocean waveguide that the inter- ference structure is stable and can be observed in the low-frequency acoustic field, in order to explore the passive ranging method suitable for the towed line array sonar. The double arrays （elements） model is adopted, so the LOFARgram and bearing-time records of the each array （element） can be obtained. Then the frequency-time records can be extracted by processing the LOFARgram via Radon transform, so the passive ranging can be achieved combined the corresponding ranging algorithms. And the feasibility of the algorithms has been verified by simulation researches and positioning accuracy analysis.展开更多
For improving passive ranging of three-sensor array, a sliding cross-correlation method is adopted to improve the performance of time delay estimation. Compared with the traditional cross-correlation, the sliding cros...For improving passive ranging of three-sensor array, a sliding cross-correlation method is adopted to improve the performance of time delay estimation. Compared with the traditional cross-correlation, the sliding cross-correlation＇s ability is evidently increased. An improved formula which is in high precision for near target is employed. An algorithm of kicking out wild value is presented, which is on line, can track the target automatically. The algorithm named ＂round filter＂ can pick out the data in high quality with robustness. A ＂dynamic filter＂ is presented, which is combined with the ＂round filter＂ as the post processor. The experimental result of three-sensor array passive ranging of near field target in shallow water is introduced, which suggests that the post processor is indeed obvious in improving the ranging performance.展开更多
The high rate digital acoustic communication technique for horizontal channels has been studied in this article. It is called as 'Pattern Time Delay Shift Coding (PDS) communication system.' The aim of the PDS...The high rate digital acoustic communication technique for horizontal channels has been studied in this article. It is called as 'Pattern Time Delay Shift Coding (PDS) communication system.' The aim of the PDS is to improve the quality of communication in shallow water. The open water experiments shoe that at the condition of 2 kHz bandwidth, the communication rate is more than 300 bit/s and error rate is at the level of 10-4. The details of PDS technique will be shown, including: principle of PDS coding, the model of Anti-multipath illterference and open water experimenis展开更多
The experiments for the sound scattering of the ship wakes are introduced in this article. The wakes are detected in both horizon and vertical in lake trials and its traces are shown in display model A or B, Its si...The experiments for the sound scattering of the ship wakes are introduced in this article. The wakes are detected in both horizon and vertical in lake trials and its traces are shown in display model A or B, Its size and sound scattering strength are measured also. The scattering signals are analysed with the instananeous frequency sequence statistics methods展开更多
The technology of underwater acoustic image measurement was a passive locating method with high precision in near field. To improve the precision of underwater acoustic image measurement, the influence of the depth sc...The technology of underwater acoustic image measurement was a passive locating method with high precision in near field. To improve the precision of underwater acoustic image measurement, the influence of the depth scan error was analyzed and the correction method was presented. For a pass array navigation process, when the scan depth was deeper than the real depth of target, the measurement errors could be corrected, and the real depth could be calculated. Otherwise the depth error couldn＇t be corrected. The simulations and the experiments were done. The results were satisfying and consistent with the theoretical conclusions.展开更多
The technology of source space distribution imaging measurement is a passive object positioning method with high precision in the near field, which also can get the distribution image of ship＇s radiated noise sources...The technology of source space distribution imaging measurement is a passive object positioning method with high precision in the near field, which also can get the distribution image of ship＇s radiated noise sources and locate the ghts of the target. The sea trials have been carried out, and the results validate the feasibility and practicability of this tech-nology. The researches indicate that the measurement precision can be achieved at the meter level within the range of 200 m using the uniform linear array which has the length of 45 m and 10 elements, and the method shows good robustness. The results also provide that the general ship can be simplified as single highlight model at 2-10 kHz in the near field and the catamaran is double highlights while its two propellers are working at the same time.展开更多
The splash sound of target＇s water entry is an instantaneous signal, consisting of impact component and bubble components. It is difficult to detect and estimate the azimuth of this signal by traditional azimuth esti...The splash sound of target＇s water entry is an instantaneous signal, consisting of impact component and bubble components. It is difficult to detect and estimate the azimuth of this signal by traditional azimuth estimation methods using a single vector sensor, especially when the SNR is low. Empirical mode decomposition is a nonlinear analysis method that can emphasize signals＇ instantaneous characteristic. In this paper, the pressure and particle velocities are decomposed into different intrinsic mode functions （IMF）, and the MAIA （mode acoustic intensity averager） method can realize the instantaneous signals＇ detection and azimuth estimation. The lake experiment and sea trial results show that this method can decompose water-entry sound and ambient interference into different IMFs, so as to detect the starting time of water-entry sound signal and estimate its azimuth effectively.展开更多
文摘Two kinds of passive ranging algorithms are proposed combined with waveguide invariant theory based on the important characteristic of the ocean waveguide that the inter- ference structure is stable and can be observed in the low-frequency acoustic field, in order to explore the passive ranging method suitable for the towed line array sonar. The double arrays （elements） model is adopted, so the LOFARgram and bearing-time records of the each array （element） can be obtained. Then the frequency-time records can be extracted by processing the LOFARgram via Radon transform, so the passive ranging can be achieved combined the corresponding ranging algorithms. And the feasibility of the algorithms has been verified by simulation researches and positioning accuracy analysis.
基金supported by the National Defense Key Laboratory Fund(9140C2001010801)by the Shipping Industry Technology Fund(07j3.1.3)
文摘For improving passive ranging of three-sensor array, a sliding cross-correlation method is adopted to improve the performance of time delay estimation. Compared with the traditional cross-correlation, the sliding cross-correlation＇s ability is evidently increased. An improved formula which is in high precision for near target is employed. An algorithm of kicking out wild value is presented, which is on line, can track the target automatically. The algorithm named ＂round filter＂ can pick out the data in high quality with robustness. A ＂dynamic filter＂ is presented, which is combined with the ＂round filter＂ as the post processor. The experimental result of three-sensor array passive ranging of near field target in shallow water is introduced, which suggests that the post processor is indeed obvious in improving the ranging performance.
文摘The high rate digital acoustic communication technique for horizontal channels has been studied in this article. It is called as 'Pattern Time Delay Shift Coding (PDS) communication system.' The aim of the PDS is to improve the quality of communication in shallow water. The open water experiments shoe that at the condition of 2 kHz bandwidth, the communication rate is more than 300 bit/s and error rate is at the level of 10-4. The details of PDS technique will be shown, including: principle of PDS coding, the model of Anti-multipath illterference and open water experimenis
文摘The experiments for the sound scattering of the ship wakes are introduced in this article. The wakes are detected in both horizon and vertical in lake trials and its traces are shown in display model A or B, Its size and sound scattering strength are measured also. The scattering signals are analysed with the instananeous frequency sequence statistics methods
文摘The technology of underwater acoustic image measurement was a passive locating method with high precision in near field. To improve the precision of underwater acoustic image measurement, the influence of the depth scan error was analyzed and the correction method was presented. For a pass array navigation process, when the scan depth was deeper than the real depth of target, the measurement errors could be corrected, and the real depth could be calculated. Otherwise the depth error couldn＇t be corrected. The simulations and the experiments were done. The results were satisfying and consistent with the theoretical conclusions.
基金supported by the Foundation for Basic Research of Harbin Engineering University (HEUFT07018)Pre-Research Foundation of Shipbuilding Industry(07j3.1.3)
文摘The technology of source space distribution imaging measurement is a passive object positioning method with high precision in the near field, which also can get the distribution image of ship＇s radiated noise sources and locate the ghts of the target. The sea trials have been carried out, and the results validate the feasibility and practicability of this tech-nology. The researches indicate that the measurement precision can be achieved at the meter level within the range of 200 m using the uniform linear array which has the length of 45 m and 10 elements, and the method shows good robustness. The results also provide that the general ship can be simplified as single highlight model at 2-10 kHz in the near field and the catamaran is double highlights while its two propellers are working at the same time.
基金supported by the National Defense Key Laboratory Fund(9140C200101080C2005)the Harbin Engineering University Basic Research Fund(HEUFT07072)
文摘The splash sound of target＇s water entry is an instantaneous signal, consisting of impact component and bubble components. It is difficult to detect and estimate the azimuth of this signal by traditional azimuth estimation methods using a single vector sensor, especially when the SNR is low. Empirical mode decomposition is a nonlinear analysis method that can emphasize signals＇ instantaneous characteristic. In this paper, the pressure and particle velocities are decomposed into different intrinsic mode functions （IMF）, and the MAIA （mode acoustic intensity averager） method can realize the instantaneous signals＇ detection and azimuth estimation. The lake experiment and sea trial results show that this method can decompose water-entry sound and ambient interference into different IMFs, so as to detect the starting time of water-entry sound signal and estimate its azimuth effectively.
