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Underwater Acoustics Research

  (1) Advanced SOnar Range Prediction System , ASORPS
  (2) Underwater Acoustic Propagation (2D/3D, Low-Mid         Frequency)
  (3) Uncertainty/Sonar Performance
  (4) Ambient Noise Model/Observation
  (5) Marine Mammal/Bio-Detection/Sound Identification
  (6) Underwater Acoustic Communication
  (7) Geo-acoustics/Inversion

Field Works/Joint Programs

  ü  ASIAEX, 2000~2001 (NSC/ONR, WHOI/NPS/NRL/MIT)
  ü  VANS/WISE, 2005-2006 (NSC/ONR, NPS)
  ü  OAJEX, 2005-2013 (NSC)
  ü  ACOMMS, since 2006 (NSC)
  ü  NLIWI, 2007-2008 (NSC/ONR, NPS)
  ü  QPE, 2008-2010 (NSC/ONR, WHOI/OASIS/MIT)
  ü  Sand Dune Experiment 2012-2014 (NSC/ONR, NSYSU/NPS)

Sound Waves Environmental Study

     Taiwan is an island surrounded by oceans, including the South China Sea in which you can find internal waves. Additionally, they can be found in the waters Northeast and Southwest of Taiwan. The laboratory has been collaborating with the United States and other countries since 2000 to conduct experiments on the effects internal waves and the environment have on voices. The results included sound wave propagation conditions in the environment, which is very complex. The main idea is to follow the relative angle sound waves propagate in the transmission path and to divide it into a two-dimensional effect and a three-dimensional effect. If the angle of sound propagation’s path interlaps with the internal wave propagation direction, the internal waves will cause the sound in the vertical direction of the energy distribution to change and cause the fixed receiving point to have an energy flux; this is the two-dimensional effect. If the angle created by the sound propagation path and internal wave propagation direction is larger than the case of internal waves generated, sound will refract in the horizontal direction and the sound energy will focus and diverge in the horizontal plane; this is the three-dimensional effect.



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Underwater Communication Research

     Passive Phase Conjugation methods (PPC) use mainly sound waves to reach the model properties of orthogonal characteristics. Other shallow water waveguides can be applied to the environment and other communication technologies. Based on the findings, PPC can be used as a pre-equalizer with a post as a non-linear or linear equalizer DFE and LE and other has other advantages that can be used to reduce the number of factors to calculate the post-equalizer and even calculate to a fixed coefficient. Additionally, there is no change in the dependent variable when the channel is changed. This equalization system uses received signals communicated when the environment responds to a pulse released at the turn of a waveguard correlation function for channel equalization, in order to reduce inter-symbol interference communication yards. Comparisons of active and passive phase conjugation methods both use acoustic propagation characteristics to achieve the goal of the research results of the theoretical basis of communication, conjugate observations of the Law of Shallow Water Model Composition and characteristics of passive acoustic propagation. This is based on the phase of effect composition has on acoustic modes to reduce the original theory in array processing and multi-channel combining. The complexity of this model composition, based observations form the basis of reducing system complexity. Studies found that the greater the difference in the model composition of the waveguide in shallow water environments, the more conducive to passive phase conjugate calculation of the effectiveness of the equalizer, The simpler the model composition, the more it could not be neutralized and thus failed to effectively reduce error. The results may provide information as a PPC array design based on the law which includes observing the model composition of the sound field and thus achieving the goal of an array of optimization and reducing the complexity of the system.


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Underwater Echoes Model Development

     Underwater echoes are used for detecting performance and have a significant impact on the effectiveness of communication in our laboratory as we use a high-frequency sound field to calculate their own mode of development (NTURAY). Combined with the Perturbation Theory, development in seabed echo modes are used to simulate the roughness of the bed interface caused by the scattering of acoustic echo signals. This research can be applied to estimate the effectiveness of the development of sonar and communications systems.

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Research on Ocean Sound Wave Transfers in Northeast Taiwan

     This study focuses on the waters northeast Taiwan where sound transmission loss characteristics and the statistical uncertainty analysis from 97 years earlier resulted in new experiments performed several times to complete the sound transmission loss data collection and to update the analysis of the nearby waters acoustic parameters characteristic variations. From the analysis of the experimental data, it was noted that the mass placed in cold water can cause a substantial increase in sound transmission loss resulting in a loss of 20dB or more. However, if there was an increase and decrease of the presence of the interaction, the sound transmission loss of the mass in cold water and internal tide was only about 10dB. In addition, internal waves caused by the acoustic propagation hydrological disturbance were quickly affected due to internal waves being generated by the two-dimensional and three-dimensional propagation effects. There was also a correlation between the received energy and the distance of the two ships. Furthermore, this study statistically analyzed estimated analog sound transmission losses. Now with better data in addition to the improved seeding mode, uncertainty of the Northeast waters was reduced greatly.



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Estimating the Effectiveness of the Developing Sonar

     Besides detecting latent tactical use, in addition to the function itself, another function for the sonar equipment is to detect different operating modes and detect latent sea in the distance. Thus, there is considerable understanding for the benefit of the best tactical reconnaissance dive. Taiwan's anti-submarine, hydrological environment surrounding the use of time and space is very big change. It is impossible to correctly estimate a simple empirical model to detect the effectiveness of sonar systems, so in the anti-submarine vehicle a computer-aided calculation of "instant" detection system effectiveness analysis was installed. The effectiveness of the ship quickly provided detection of various types of sonar, and recommended the best system set. In addition, the sonar effectiveness analysis focused on the estimate of the effective detection range, and estimated to begin the analysis system for the development of the detection range.

     After a long time, the laboratory was able to get the Navy anti-submarine warfare command. A funded aviation anti-submarine ship was ordered at the technical support of the Ocean Survey, the National Science Council, and the National Defense Science and Technology Sub-Defense Foundation. There was also a development of a several programs including a high-frequency sound transmission loss calculation program, a reverberation and background noise calculation program, sonar detection range solver programs, and Windows interface interactive programs called "Advanced Sonar Detection Distance Estimated Systems" (ASORPS).



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Studies about the Seabed and Parameter Inverses

     When sound propagating in the ocean comes in contact with or into the sea bed, it will be produced by the physical characteristics of the sea bed of various physical mechanisms, such as radio, reflection and absorption.

     However, the cause of these mechanisms is due to the internal characteristics of the seabed, these features include speed, density, and absorption rate. Due to these characteristics, sediment sampling is difficult. Therefore, to estimate the acoustic sound parameters it is important to consider the application of marine acoustics. Deputy Director of the Department of Taipei College of Maritime Technology, 王崇武, decided to assist the process. The latest research includes the usage of a SB-512I Chirp Sonar to detect waters northeast of Taiwan. The data collected by "Hamilton" will be used with the empirical formula used to calculate seabed texture, tone, and parameter inverse.

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Experimental Study of the Sea Over the Years


Experiment Name

Experiment Area

Domestic Experiments

Jun 1993

Northeast Sea Sound Transmission Experiment

Northeast Sea

Jan 1995

Numerical Simulation of Three-Dimensional Lattice Restated Technology

Southwest Sea

May 1995

Southwest Sound Transmission Experiment

Southwest Sea


Northeast Sound Transmission Experiment

Northeast Sea

Nov 2003

Northeast Sound Test

Northeast Sea

Jun 2004

Taiwan Strait Sound Transmission Experiment

Taiwan Strait

Mar 2005

Hydrological Observations of the Southwest Waters

Southwest Sea

Aug 2005

OAJEX Experiment in Northeast Waters

Turtle Island

Mar 2006

OAJEX Water Test (Southwest)

PingTung Canyon

Apr 2006

OAJEX Water Test (Southwest)


Sept 2007

OAJEX Water Test (Southwest)

PingTung Canyon

Aug-Sept 2008

QPE Experiment (Northeast)

Northern Cotton Canyon

Mar 2009

Tamsui Sound Transmission Experiment


Apr 2009

QPE Experiment (Northeast)

Cotton Canyon

Aug 2009

QPE Experiment (Northeast)

North Cotton Canyon

International Joint Experiments

May 2001

ASEAEX Experiment

South China Sea

Apr 2005

VANS/WISE Experiment

South China Sea

Apr 2007

NLIWI Experiment

South China Sea

Apr 2008

Taiwan and Russia Bilateral Joint Experiment

Northeast Sea

Aug-Sept 2008

QPE Pilot Experiment

North Cotton Canyon

Aug-Sept 2009

QPE IOP Experiments

North Cotton Canyon

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