Statistical Analysis of the Sonar Detection Range in the South China Sea
Date Issued
2005
Date
2005
Author(s)
Chang, Yuan-Ying
DOI
en-US
Abstract
The passive sonar system has been extensively used to detect and accomplish the other tasks. But the sonar performance of passive sonar system will be intensively affected by the ocean fluctuation, and will interfere the operation of passive sonar. This thesis thus studies the relationship between ocean environment fluctuation and sonar performance by using the environmental and acoustic data in Asian Seas International Acoustic Experiment (ASIAEX).
The ASIAEX South China Sea Component was conducted in 2001, and the measured data reveal that the internal wave activities are persistent and violent. It not only causes the rapid fluctuations in ocean environment but also damages the stability of the acoustical propagation. Moreover, the internal wave field would be categorized into internal tide field and nonlinear internal wave field by the period and the reaction activity. So that the in situ data measured in ASIAEX could be provided to investigate the fluctuations of the sonar performance among these two typical dynamic ocean environments.
Because the received signals from only vertical line array can not interpret the acoustic fields along the acoustic propagation path, the sonar performance along this path could not be obtained. In this thesis, the in situ temperature profile has been utilized to obtain the model-based acoustical propagation filed and has been compared with the acoustic data to inspect the accuracy of the simulation results. The results show the model-based sound field match well to the data and the transmission loss is decreasing with depth because of the downward refracting sound speed profile. Compare the results in these two dynamic ocean environments, i.e. internal tide and nonlinear internal wave fields, the analysis result show that the propagation loss in the internal tidal field is larger than that in the nonlinear internal wave field.
Two parameters which used to analyze the sonar performance are detection range and probability of detection. Two parameters are analyzed statistically because of the violent fluctuation in the ocean environment. The results present that the sonar performance is better in the nonlinear internal wave field but also suffers higher variation in the nonlinear internal wave field.
Subjects
被動聲納
偵測距離
累績偵測機率
內波
passive sonar
detection range
probability of detection
internal wave
Type
thesis
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