Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535746
Wu Yanqun, Ana Bela dos Santos, P. Felisberto, S. Jesus
Distant ship noise has been utilized for geoacoustic inversion and ocean monitoring for many years. In a shallow water experiment, Makai 2005, a 4-element acoustic vector sensor array was deployed at the stern of the research vessel R/V Kilo Moana. The recorded engine noise of R/V Kilo Moana during its dynamic positioning was analyzed by the DEMON (Detection of Envelope Modulation on Noise) method. The strongest modulation frequency band of the ship noise was found by a group of band-pass filters for further data processing. Multipath arrivals in the vertical particle velocity have higher signal-to-noise ratios than those in the horizontal particle velocities because of steep arrival directions. By exploiting this advantage, the cross-correlation of broadband ship noise between the pressure and the vertical particle velocity can be used for multipath information exploration. Since ship noise is often characterized as continuous broadband noise plus strong tonal noise, the cross-correlation of tonal noise would dominate that of broadband noise, and consequently cover the multipath arrival pattern. Therefore, spectral weighting functions are applied in order to reduce the noise contamination and ensure sharp multipath peaks in the cross-correlation. For engine noise emitted by the dynamically positioned ship, a short correlation time of 0.4s was used in order to keep the time delay fluctuation details of multipath arrivals. Clear multiple arrivals are seen in the cross-correlation of different arrivals, and verified by the ray tracing program TRACEO. The results demonstrate the potential of only one acoustic vector sensor in applications of source localization and geoacoustic inversion.
远洋船舶噪声用于地球声反演和海洋监测已有多年历史。在马凯2005年的一次浅水实验中，在科考船R/V基洛莫阿纳的尾部部署了一个4元声矢量传感器阵列。采用噪声包络调制检测(Detection of Envelope Modulation on noise, DEMON)方法对R/V“基洛莫阿纳”动态定位过程中记录的发动机噪声进行了分析。通过一组带通滤波器找出船舶噪声的最强调制频带，进行进一步的数据处理。由于到达方向陡峭，垂直粒子速度下的多径到达比水平粒子速度下的多径到达具有更高的信噪比。利用这一优势，利用宽频船舶噪声在压力和垂直粒子速度之间的相互关系进行多径信息探测。由于船舶噪声通常表现为连续宽带噪声加强调性噪声，因此调性噪声的相互关系将压倒宽带噪声的相互关系，从而覆盖多径到达模式。因此，为了减少噪声污染，保证互相关中的多径峰清晰，采用了谱加权函数。对于动态定位船舶发出的发动机噪声，为了保持多径到达时的时延波动细节，采用了0.4s的短相关时间。在不同到达点的相互关联中可以看到清晰的多个到达点，并通过光线追踪程序TRACEO进行验证。结果表明，单一声矢量传感器在声源定位和地球声反演中的应用潜力巨大。
{"title":"Close range ship noise cross correlations with a vector sensor in view of geoacoustic inversion","authors":"Wu Yanqun, Ana Bela dos Santos, P. Felisberto, S. Jesus","doi":"10.1109/COA.2016.7535746","DOIUrl":"https://doi.org/10.1109/COA.2016.7535746","url":null,"abstract":"Distant ship noise has been utilized for geoacoustic inversion and ocean monitoring for many years. In a shallow water experiment, Makai 2005, a 4-element acoustic vector sensor array was deployed at the stern of the research vessel R/V Kilo Moana. The recorded engine noise of R/V Kilo Moana during its dynamic positioning was analyzed by the DEMON (Detection of Envelope Modulation on Noise) method. The strongest modulation frequency band of the ship noise was found by a group of band-pass filters for further data processing. Multipath arrivals in the vertical particle velocity have higher signal-to-noise ratios than those in the horizontal particle velocities because of steep arrival directions. By exploiting this advantage, the cross-correlation of broadband ship noise between the pressure and the vertical particle velocity can be used for multipath information exploration. Since ship noise is often characterized as continuous broadband noise plus strong tonal noise, the cross-correlation of tonal noise would dominate that of broadband noise, and consequently cover the multipath arrival pattern. Therefore, spectral weighting functions are applied in order to reduce the noise contamination and ensure sharp multipath peaks in the cross-correlation. For engine noise emitted by the dynamically positioned ship, a short correlation time of 0.4s was used in order to keep the time delay fluctuation details of multipath arrivals. Clear multiple arrivals are seen in the cross-correlation of different arrivals, and verified by the ray tracing program TRACEO. The results demonstrate the potential of only one acoustic vector sensor in applications of source localization and geoacoustic inversion.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117087763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535827
Yang Chunmei, Lyu Liangang, Q. Fangli, Luo Wenyu
An exact analytical solution for three-dimensional sound propagation excited by a point source in a penetrable wedge-shaped ocean is first presented in this paper. Although Deane and Buckingham have proposed an analytical solution for the acoustic field in the water of a penetrable wedge (Journal of the Acoustical Society of America, 1993, 93(3): 1319~1328), the analytical solution is not complete. It is only applicable for sea water not for the seabed, hereafter called bottom. This paper presents an analytical field solution which not only applies to sea water but also the bottom. The analytical solution is obtained by using the method of source images. For the acoustic field in the water of a penetrable wedge, only acoustic reflection needs to be considered. All the source images on a circle centered on the wedge apex need to be involved in the computation. However, for the acoustic field at the bottom of a penetrable wedge, both acoustic reflection and acoustic refraction need to be considered. Only the source images above the bottom on a semicircle need to be involved in the computation. The analytical solution in the whole sea area can be obtained based on the plane wave reflection and refraction principles. In addition, a three-dimensional numerical model based on the wavenumber integration method is also presented and implemented in an unconditionally stable direct-global-matrix coupled-mode method. Afterwards, the three-dimensional numerical model is applied to sound propagation excited by a point source in a benchmark wedge waveguide. The numerical solutions from the three-dimensional model agree well with the analytical solutions in the benchmark wedge waveguide. Consequently, the present three-dimensional model is validated through the analytical solutions to the benchmark wedge problem.
本文首次给出了可穿透楔形海洋中由点源激发的三维声传播的精确解析解。虽然Deane和Buckingham已经提出了可穿透楔体水中声场的解析解(Journal of acoustic Society of America, 1993,93(3): 1319~1328)，但解析解并不完整。它只适用于海水，不适用于海床，以下称为底部。本文提出了一种既适用于海水也适用于海底的解析场解。采用源图像法得到了解析解。对于可穿透楔体的水中声场，只需考虑声反射。以楔形顶点为中心的圆上的所有源图像都需要参与计算。然而，对于可穿透楔形底部的声场，需要同时考虑声反射和声折射。只有位于半圆底部上方的源图像需要参与计算。基于平面波反射和折射原理，可以得到整个海域的解析解。此外，还提出了基于波数积分法的三维数值模型，并以无条件稳定的直接全局矩阵耦合模式方法实现。然后，将三维数值模型应用于基准楔形波导中点源激励下的声音传播。三维模型的数值解与基准楔形波导的解析解吻合较好。因此，通过基准楔问题的解析解，验证了该三维模型的有效性。
{"title":"Three-dimensional analytical solution and numerical solution in a penetrable wedge-shaped waveguide","authors":"Yang Chunmei, Lyu Liangang, Q. Fangli, Luo Wenyu","doi":"10.1109/COA.2016.7535827","DOIUrl":"https://doi.org/10.1109/COA.2016.7535827","url":null,"abstract":"An exact analytical solution for three-dimensional sound propagation excited by a point source in a penetrable wedge-shaped ocean is first presented in this paper. Although Deane and Buckingham have proposed an analytical solution for the acoustic field in the water of a penetrable wedge (Journal of the Acoustical Society of America, 1993, 93(3): 1319~1328), the analytical solution is not complete. It is only applicable for sea water not for the seabed, hereafter called bottom. This paper presents an analytical field solution which not only applies to sea water but also the bottom. The analytical solution is obtained by using the method of source images. For the acoustic field in the water of a penetrable wedge, only acoustic reflection needs to be considered. All the source images on a circle centered on the wedge apex need to be involved in the computation. However, for the acoustic field at the bottom of a penetrable wedge, both acoustic reflection and acoustic refraction need to be considered. Only the source images above the bottom on a semicircle need to be involved in the computation. The analytical solution in the whole sea area can be obtained based on the plane wave reflection and refraction principles. In addition, a three-dimensional numerical model based on the wavenumber integration method is also presented and implemented in an unconditionally stable direct-global-matrix coupled-mode method. Afterwards, the three-dimensional numerical model is applied to sound propagation excited by a point source in a benchmark wedge waveguide. The numerical solutions from the three-dimensional model agree well with the analytical solutions in the benchmark wedge waveguide. Consequently, the present three-dimensional model is validated through the analytical solutions to the benchmark wedge problem.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126146193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535814
B. Katsnelson, Yun Ren
On the base of experimental data of ASIAEX 01 and the corresponding theoretical analysis it is shown existence of predominating frequencies in spectrum of the sound intensity fluctuations in the presence of nonlinear internal waves moving along acoustic track. Both the speed of internal waves and scales of interference beating of waveguide modes determine mentioned frequencies.
{"title":"Sound intensity fluctuations due to mode coupling on moving internal waves","authors":"B. Katsnelson, Yun Ren","doi":"10.1109/COA.2016.7535814","DOIUrl":"https://doi.org/10.1109/COA.2016.7535814","url":null,"abstract":"On the base of experimental data of ASIAEX 01 and the corresponding theoretical analysis it is shown existence of predominating frequencies in spectrum of the sound intensity fluctuations in the presence of nonlinear internal waves moving along acoustic track. Both the speed of internal waves and scales of interference beating of waveguide modes determine mentioned frequencies.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130008980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535695
Ming Yue, Y. R. Zheng, Zhenrui Chen, Yunfeng Han
This paper proposes a low-complexity dual pseudorandom noise (PN) scheme for identity (ID) detection and coarse frame synchronization. The two PN sequences are identical and are separated by a specified length of gap which serves as the ID for different sensor nodes. The receiver ID detection is implemented on a microcontroller MSP430F5529 by calculating the correlation between the two segments of the received signal with the specified separation gap. When the gap length is matched with the ID, the correlator outputs a peak which sets the wakeup enable. The time index of the correlator peak is used as the coarse synchronization of the data frame. An iterative algorithm is used that requires only one multiplication and two additions for each sample input regardless of the length of the PN sequences, thus achieving low computational complexity. The proposed dual PN detection scheme has been successfully tested by simulated fading channels and real-world measured channels. The results show that, in long multipath channels with more than 60 taps, the proposed scheme achieves high detection rate and low false alarm rate using maximal-length sequences as short as 31 bits to 127 bits, therefore it is suitable as a low-power wake-up receiver.
{"title":"Microcontroller implementation of low-complexity wake-up receiver for wireless sensor nodes in severe multipath fading channels","authors":"Ming Yue, Y. R. Zheng, Zhenrui Chen, Yunfeng Han","doi":"10.1109/COA.2016.7535695","DOIUrl":"https://doi.org/10.1109/COA.2016.7535695","url":null,"abstract":"This paper proposes a low-complexity dual pseudorandom noise (PN) scheme for identity (ID) detection and coarse frame synchronization. The two PN sequences are identical and are separated by a specified length of gap which serves as the ID for different sensor nodes. The receiver ID detection is implemented on a microcontroller MSP430F5529 by calculating the correlation between the two segments of the received signal with the specified separation gap. When the gap length is matched with the ID, the correlator outputs a peak which sets the wakeup enable. The time index of the correlator peak is used as the coarse synchronization of the data frame. An iterative algorithm is used that requires only one multiplication and two additions for each sample input regardless of the length of the PN sequences, thus achieving low computational complexity. The proposed dual PN detection scheme has been successfully tested by simulated fading channels and real-world measured channels. The results show that, in long multipath channels with more than 60 taps, the proposed scheme achieves high detection rate and low false alarm rate using maximal-length sequences as short as 31 bits to 127 bits, therefore it is suitable as a low-power wake-up receiver.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123913636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535747
Zhang Youwen, Hong Xiaoping, W. Yonggang, Sun Da-jun
The Frequency Hopping (FH) communication technique is one of classical methods of spread spectrum communication techniques, and it is widely used in terrestrial and underwater communications due to its robustness to jamming, low probability of interception and facility in communication networking. In particular, estimating and tracking the parameters of FH signals are important tasks in underwater acoustic warfare. This paper applies gridless SPICE (GLS) to the parameter estimation of underwater acoustic FH signals, mainly focused on time-frequency pattern and hop timing. As compared to the conventional spectrogram method, the time-frequency analysis method based on gridless SPICE has better frequency acquisition for the same samples. As compared to the SLR method proposed by Daniele Angelosante, this method has better performance for estimating parameters when we do not know the hopping frequency set.
{"title":"Gridless SPICE applied to parameter estimation of underwater acoustic Frequency Hopping signals","authors":"Zhang Youwen, Hong Xiaoping, W. Yonggang, Sun Da-jun","doi":"10.1109/COA.2016.7535747","DOIUrl":"https://doi.org/10.1109/COA.2016.7535747","url":null,"abstract":"The Frequency Hopping (FH) communication technique is one of classical methods of spread spectrum communication techniques, and it is widely used in terrestrial and underwater communications due to its robustness to jamming, low probability of interception and facility in communication networking. In particular, estimating and tracking the parameters of FH signals are important tasks in underwater acoustic warfare. This paper applies gridless SPICE (GLS) to the parameter estimation of underwater acoustic FH signals, mainly focused on time-frequency pattern and hop timing. As compared to the conventional spectrogram method, the time-frequency analysis method based on gridless SPICE has better frequency acquisition for the same samples. As compared to the SLR method proposed by Daniele Angelosante, this method has better performance for estimating parameters when we do not know the hopping frequency set.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115230830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535723
Song Hao, He Yuan-an, Yang Xiaowei, D. Shang
The flow noise has become an important factor affecting the acoustical stealth performance of AUV in high speed. In the broad sense, all of the radiated noise caused by the instability of the flow field is called flow noise, including the fluid's own noise and noise radiation from flow-induced vibration. Both of the two subclasses of flow-induced noise are investigated in this paper and a precise and efficient numerical method is introduced. With the commercial computational fluid dynamics (CFD) software Fluent and acoustical finite-element method (FEM) software ACTRAN tuned to work jointly with types of preprocessing and post processing software, a computing mechanism combined with large eddy simulation, structural FEM and Lighthill acoustic analogy theory was established. A fluid-structure interaction handling method for shell elements with heavy fluid on both sides was also constructed, which achieves a remarkable reduction on manpower and computational cost on modeling and discrediting the shell structures. A prominent improvement in performance for a flow-induced noise solver on submerged complicated shell structures is also observed. For the validation of our method on both flow-stimulated radiation and flow-induced noise, a number of experiments were conducted on flow-stimulated thin shells and cavity flow-induced noise, consist with the general law of fluid-noise. The method was then applied to the flow-induced noise from a submerged wing-shaped cavity and nozzle, and the pattern of corresponding flow field and sound field further investigated. A corrected reverberation measuring method was also established to overcome the difficulty of flow-noise induced by the noise measurement. Once the spatial mean level of sound pressure in the reverberation control area is measured and corrected, the sound radiation power induced by a submerged complicated source can then be swiftly obtained. The computing method combined with large eddy simulation, structural FEM and Lighthill acoustic analogy theory is further validated by experiments on the flow-induced noise from a submerged wing-shaped cavity in the gravitational water tunnel of an underwater acoustic technique laboratory using our reverberation chamber measuring method. The experimental data fits the simulation solution well.
{"title":"A numerical simulation of flow-induced noise from cavity based on LES and Lighthill acoustic theory","authors":"Song Hao, He Yuan-an, Yang Xiaowei, D. Shang","doi":"10.1109/COA.2016.7535723","DOIUrl":"https://doi.org/10.1109/COA.2016.7535723","url":null,"abstract":"The flow noise has become an important factor affecting the acoustical stealth performance of AUV in high speed. In the broad sense, all of the radiated noise caused by the instability of the flow field is called flow noise, including the fluid's own noise and noise radiation from flow-induced vibration. Both of the two subclasses of flow-induced noise are investigated in this paper and a precise and efficient numerical method is introduced. With the commercial computational fluid dynamics (CFD) software Fluent and acoustical finite-element method (FEM) software ACTRAN tuned to work jointly with types of preprocessing and post processing software, a computing mechanism combined with large eddy simulation, structural FEM and Lighthill acoustic analogy theory was established. A fluid-structure interaction handling method for shell elements with heavy fluid on both sides was also constructed, which achieves a remarkable reduction on manpower and computational cost on modeling and discrediting the shell structures. A prominent improvement in performance for a flow-induced noise solver on submerged complicated shell structures is also observed. For the validation of our method on both flow-stimulated radiation and flow-induced noise, a number of experiments were conducted on flow-stimulated thin shells and cavity flow-induced noise, consist with the general law of fluid-noise. The method was then applied to the flow-induced noise from a submerged wing-shaped cavity and nozzle, and the pattern of corresponding flow field and sound field further investigated. A corrected reverberation measuring method was also established to overcome the difficulty of flow-noise induced by the noise measurement. Once the spatial mean level of sound pressure in the reverberation control area is measured and corrected, the sound radiation power induced by a submerged complicated source can then be swiftly obtained. The computing method combined with large eddy simulation, structural FEM and Lighthill acoustic analogy theory is further validated by experiments on the flow-induced noise from a submerged wing-shaped cavity in the gravitational water tunnel of an underwater acoustic technique laboratory using our reverberation chamber measuring method. The experimental data fits the simulation solution well.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127830694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535815
Yin Jingwei, Duan Pengyu, Zhu Guangping, Chen Wenjian, Liu Qiang
More and more scientific investigations and research activities have been carried out in arctic region, among which the related research on the Arctic Ocean is particularly important. It can be seen that arctic hydro acoustics is the significant support to guarantee military presence and normal scientific research activities. Under-ice acoustic communication experimental was done in Songhua River, Harbin, China in January 2015. Minus 20~30 degrees work environment brings a great challenge to the under-ice experimental campaign. All of the under-ice acoustic communication tests achieve low bit error rate communication at 1km range with different received depth because of the relatively stable under-ice channel. It is found that the closer to the ice the simpler the under-ice acoustic (UIA) channel structure is. Time reversal mirror (TRM) can use the physical characteristics of the UIA channel to focus toward the desired user in multi-user UIA communication. Active average sound intensity (AASI) detector can estimate all azimuths of users with the same frequency band at the same time in order to achieve directional communication by vector combination. Space-division multiple-access (SDMA) based on TRM and AASI detector is used in code-division multiple-access (CDMA) UIA communication to increase the capacity of multiuser system. A method developed for direct sequence spread spectrum communications in an underwater channel are used to extract the transmitted symbols. Under-ice data shows that as many as 12 users can be supported simultaneously in CDMA system combined with SDMA technology.
{"title":"Under-ice CDMA multiuser acoustic communications","authors":"Yin Jingwei, Duan Pengyu, Zhu Guangping, Chen Wenjian, Liu Qiang","doi":"10.1109/COA.2016.7535815","DOIUrl":"https://doi.org/10.1109/COA.2016.7535815","url":null,"abstract":"More and more scientific investigations and research activities have been carried out in arctic region, among which the related research on the Arctic Ocean is particularly important. It can be seen that arctic hydro acoustics is the significant support to guarantee military presence and normal scientific research activities. Under-ice acoustic communication experimental was done in Songhua River, Harbin, China in January 2015. Minus 20~30 degrees work environment brings a great challenge to the under-ice experimental campaign. All of the under-ice acoustic communication tests achieve low bit error rate communication at 1km range with different received depth because of the relatively stable under-ice channel. It is found that the closer to the ice the simpler the under-ice acoustic (UIA) channel structure is. Time reversal mirror (TRM) can use the physical characteristics of the UIA channel to focus toward the desired user in multi-user UIA communication. Active average sound intensity (AASI) detector can estimate all azimuths of users with the same frequency band at the same time in order to achieve directional communication by vector combination. Space-division multiple-access (SDMA) based on TRM and AASI detector is used in code-division multiple-access (CDMA) UIA communication to increase the capacity of multiuser system. A method developed for direct sequence spread spectrum communications in an underwater channel are used to extract the transmitted symbols. Under-ice data shows that as many as 12 users can be supported simultaneously in CDMA system combined with SDMA technology.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125589464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535713
Zhang Zhaohui, Hu Chen, Peng Yuan, Zhang Fengzhen, Mu Lin
Underwater target recognition is very difficult because of the complexity of the ocean environment. The existing recognition technologies are mostly based on time domain, frequency domain, and time-frequency domain. Beam forming technology is a method of target recognition that has been researched and has developed rapidly in recent years. This paper applies beam forming and spatial spectrum analysis technology to an underwater echo signal in order to capture target echo and highlight spot and dimension features in the time-space domain. Image processing is used to extract the dimension and experimental data also verifies the feasibility of this method of beam forming.
{"title":"Target spatial feature abstraction basing on beam forming","authors":"Zhang Zhaohui, Hu Chen, Peng Yuan, Zhang Fengzhen, Mu Lin","doi":"10.1109/COA.2016.7535713","DOIUrl":"https://doi.org/10.1109/COA.2016.7535713","url":null,"abstract":"Underwater target recognition is very difficult because of the complexity of the ocean environment. The existing recognition technologies are mostly based on time domain, frequency domain, and time-frequency domain. Beam forming technology is a method of target recognition that has been researched and has developed rapidly in recent years. This paper applies beam forming and spatial spectrum analysis technology to an underwater echo signal in order to capture target echo and highlight spot and dimension features in the time-space domain. Image processing is used to extract the dimension and experimental data also verifies the feasibility of this method of beam forming.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124701926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535708
Jianjun Zhu, Yukuo Wei, Haisen S. Li, Jingxin Ma
The traditional signal processing method of chirp sub-bottom profiling is a type of matched filtering and is an optimal detector when there is no Doppler shift. Fractional Fourier transform (FrFT) is a linear transformation whose orthogonal basis is a linear frequency modulation signal, so there is no cross term interference when processing multiple or multipath chirp signals. The central characteristic of FrFT is that it has a similar theoretical basis to pulse compression, which makes it possible to use FrFT in the signal processing of chirp sub-bottom profiling. In this paper, the basic principle and theory of chirp sub-bottom profiler signal processing based on FrFT is introduced in detail. Firstly, orthogonal transform is performed to obtain the corresponding analytical form of the echo signal, then the time domain signal is transformed to a fractional Fourier domain (u domain) by optimal FrFT, and the signal enhancement is done using the u domain shading method. Finally, time dimensional transform is used to get the time domain envelope signal of the enhanced sediment impulse response. Time dimensional transform is realized by sample sequence mapping, time offset compensation, extraction and low pass filtering. This process can transform a u domain signal to the time domain directly without complex calculations. Performance comparison of this method to matched filtering is given too, and recommendations for future work are presented.
{"title":"Chirp sub-bottom profiler signal processing method based on fractional Fourier transform","authors":"Jianjun Zhu, Yukuo Wei, Haisen S. Li, Jingxin Ma","doi":"10.1109/COA.2016.7535708","DOIUrl":"https://doi.org/10.1109/COA.2016.7535708","url":null,"abstract":"The traditional signal processing method of chirp sub-bottom profiling is a type of matched filtering and is an optimal detector when there is no Doppler shift. Fractional Fourier transform (FrFT) is a linear transformation whose orthogonal basis is a linear frequency modulation signal, so there is no cross term interference when processing multiple or multipath chirp signals. The central characteristic of FrFT is that it has a similar theoretical basis to pulse compression, which makes it possible to use FrFT in the signal processing of chirp sub-bottom profiling. In this paper, the basic principle and theory of chirp sub-bottom profiler signal processing based on FrFT is introduced in detail. Firstly, orthogonal transform is performed to obtain the corresponding analytical form of the echo signal, then the time domain signal is transformed to a fractional Fourier domain (u domain) by optimal FrFT, and the signal enhancement is done using the u domain shading method. Finally, time dimensional transform is used to get the time domain envelope signal of the enhanced sediment impulse response. Time dimensional transform is realized by sample sequence mapping, time offset compensation, extraction and low pass filtering. This process can transform a u domain signal to the time domain directly without complex calculations. Performance comparison of this method to matched filtering is given too, and recommendations for future work are presented.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120952322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/COA.2016.7535720
Yongheng Wang, Sun Da-jun, W. Fan, Youwen Zhang
Precise time synchronization is a foundation in the distributed wireless sensor networks in order to ensure the effective co-operation of work such as data fusion and time division scheduling. Due to the high latency caused by low sound speed and mobility between nodes in the underwater acoustic environment, it is difficult to apply mature radio time synchronization algorithms which are widely used in terrestrial networks in the underwater acoustic communication networks. In recent years, several time synchronization algorithms for underwater sensor networks have been developed. However, these algorithms are mostly in the stage of simulation research, which is based on the premise of relative static nodes which require large energy for data exchange and complex linear regression calculations. When taking the mobile platform as the time reference node, the time synchronization between nodes will lead to the problem of bidirectional delay inequality. To tackle these problems, a dynamic time synchronization algorithm based on relative speed compensation with lower energy consumption and higher reliability is proposed. Firstly, an high accuracy clock with low energy consumption is taken in the proposed algorithm to avoid the high energy consumption and large computation in the estimation processing of the clock frequency skew. Secondly, the Linear Frequency Modulation (LFM) pulse pair which can estimate the relative speed of motion is inserted during the exchanging of time information, which can estimate the link propagation delay. Thirdly, a decision mechanism with three times information interaction between two nodes is used to ensure the robustness of time synchronization. Finally, the lake experimental results show that the maximum time synchronization deviation of traditional TSHL algorithm is 18ms, whereas the maximum time synchronization deviation of the proposed algorithm is less than 6ms, and it has higher reliability when the relative speed is up to 6kt between the two nodes.
{"title":"Low consumption dynamic time synchronization for mobile and high latency underwater acoustic communication networks","authors":"Yongheng Wang, Sun Da-jun, W. Fan, Youwen Zhang","doi":"10.1109/COA.2016.7535720","DOIUrl":"https://doi.org/10.1109/COA.2016.7535720","url":null,"abstract":"Precise time synchronization is a foundation in the distributed wireless sensor networks in order to ensure the effective co-operation of work such as data fusion and time division scheduling. Due to the high latency caused by low sound speed and mobility between nodes in the underwater acoustic environment, it is difficult to apply mature radio time synchronization algorithms which are widely used in terrestrial networks in the underwater acoustic communication networks. In recent years, several time synchronization algorithms for underwater sensor networks have been developed. However, these algorithms are mostly in the stage of simulation research, which is based on the premise of relative static nodes which require large energy for data exchange and complex linear regression calculations. When taking the mobile platform as the time reference node, the time synchronization between nodes will lead to the problem of bidirectional delay inequality. To tackle these problems, a dynamic time synchronization algorithm based on relative speed compensation with lower energy consumption and higher reliability is proposed. Firstly, an high accuracy clock with low energy consumption is taken in the proposed algorithm to avoid the high energy consumption and large computation in the estimation processing of the clock frequency skew. Secondly, the Linear Frequency Modulation (LFM) pulse pair which can estimate the relative speed of motion is inserted during the exchanging of time information, which can estimate the link propagation delay. Thirdly, a decision mechanism with three times information interaction between two nodes is used to ensure the robustness of time synchronization. Finally, the lake experimental results show that the maximum time synchronization deviation of traditional TSHL algorithm is 18ms, whereas the maximum time synchronization deviation of the proposed algorithm is less than 6ms, and it has higher reliability when the relative speed is up to 6kt between the two nodes.","PeriodicalId":155481,"journal":{"name":"2016 IEEE/OES China Ocean Acoustics (COA)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130074439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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