Fig. 1. Schematic representation of target bearing (ϕ), vertical angle (μ) and estimated bearing (θ).
Fig. 2. Relationship between estimated bearing and target bearing as a function of vertical incident angle.
Fig. 3. Eigenray tracing outputs during winter for source-receiver ranges of 5 km (top), 15 km (middle) and 30 km (bottom) in the East Sea.
Fig. 4. Ray tracing outputs of bottom bounced path with sound speed profile, (a) constant SSP (1500 m/s), (b) Munk SSP (minimum sound speed at 400 m).
Fig. 5. Comparisons between the (a) simulation results of bearing error for the isovelocity condition and (b) simulation results of bearing error for the Munk profile.
Fig. 6. Simulation results of bearing errors as a function of depth for the isovelocity condition. The total water depths of experimental site are (a) 500 m, (b) 1500 m, (c) 2500 m, respectively.
Fig. 7. Sound speed profile and bathymetry of the simulation.
Fig. 9. (a) Estimated bearing line along distance from constant target bearing, (b) expected target bearing line along the distance from the constant estimated bearing.
Fig. 8. (a) Example of application of a straight line for the direct path of target signal, (b) example of application of a straight line for the bottom bounced path of target signal.
Fig. 10. Example of application of expected target bearing line along the distance from the constant estimated bearing for bottom bounced paths of the target signal.
Table 1. Bearing errors resulting from incoming signals with different vertical angles.
References
- A. D. Waite, Sonar for Practising Engineers, 3rd ed. (John Wiley and Sons Ltd, UK, 2002), pp. 158-160.
- F. B. Jensen, W. A. Kuperman, M. B. Porter, and H. Schmidt, Computational Ocean Acoustics AIP Series in Modern Acoustics and Signal Processing (American Institute of Physics, Melville, New York, 1994), pp. 584-596.
- J. S. Park, Y. N. Na, and J. W. Choi, "LIine array sonar and nethod for detecting target bearing of the same" (in Korean), Korea. patent No.10-1257097, 2014.
- M. B. Porter, "The BELLHOP Manual and User's Guide: Preliminary Draft," Heat, Light, and Sound Research, Inc. (2011).
- W. H. Munk, "Sound channel in an exponentially stratified ocean with applications to sofar," J. Acoust. Soc. Am. 55, 220-226 (1974). https://doi.org/10.1121/1.1914492
- M. R. Carnes, Description and Evaluation of GDEM-V 3.0, Naval Research Laboratory, 2009.
- C. Amante and B. W. Eakins, "Etopo1 arc-minute global relief model: procedures, data, sources and analysis," NGDC, Tech. Rep., 2003.