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Ranging in an underwater medium with multiple isogradient sound speed profile layers.

Ramezani H, Leus G - Sensors (Basel) (2012)

Bottom Line: In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment.The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP) layers where in each layer the sound speed is linearly related to the depth.Furthermore, each sensor node is able to measure its depth and can exchange this information with other nodes.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, The Netherlands. h.mashhadiramezani@tudelft.nl

ABSTRACT
In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment. The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP) layers where in each layer the sound speed is linearly related to the depth. Furthermore, each sensor node is able to measure its depth and can exchange this information with other nodes. Under these assumptions, we first show how the problem of underwater localization can be converted to the traditional range-based terrestrial localization problem when the depth information of the nodes is known a priori. Second, we relate the pair-wise time of flight (ToF) measurements between the nodes to their positions. Next, based on this relation, we propose a novel ranging algorithm for an underwater medium. The proposed ranging algorithm considers reflections from the seabed and sea surface. We will show that even without any reflections, the transmitted signal may travel through more than one path between two given nodes. The proposed algorithm analyzes them and selects the fastest one (first arrival path) based on the measured ToF and the nodes' depth measurements. Finally, in order to evaluate the performance of the proposed algorithm we run several simulations and compare the results with other existing algorithms.

No MeSH data available.


Related in: MedlinePlus

Linear dependency of the reflection and crossing points under the assumption of a perfect reflection.
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f4-sensors-12-02996: Linear dependency of the reflection and crossing points under the assumption of a perfect reflection.

Mentions: Under the assumption of a perfect reflection, the reflected parts in different layers have the same properties as the corresponding non-reflected parts but with an axial symmetry around the line parallel to the z-axis crossing the reflection point as illustrated in Figure 4. Due to this symmetry which is resulted by the cylindrical symmetry of the ray propagation, the r-coordinate of the two crossing points around a reflection point are linearly related to each other, and one can be formulated by the r-coordinate of the other. Therefore, this does not change the degree of the polynomial resulting from such kinds of ray patterns.


Ranging in an underwater medium with multiple isogradient sound speed profile layers.

Ramezani H, Leus G - Sensors (Basel) (2012)

Linear dependency of the reflection and crossing points under the assumption of a perfect reflection.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376626&req=5

f4-sensors-12-02996: Linear dependency of the reflection and crossing points under the assumption of a perfect reflection.
Mentions: Under the assumption of a perfect reflection, the reflected parts in different layers have the same properties as the corresponding non-reflected parts but with an axial symmetry around the line parallel to the z-axis crossing the reflection point as illustrated in Figure 4. Due to this symmetry which is resulted by the cylindrical symmetry of the ray propagation, the r-coordinate of the two crossing points around a reflection point are linearly related to each other, and one can be formulated by the r-coordinate of the other. Therefore, this does not change the degree of the polynomial resulting from such kinds of ray patterns.

Bottom Line: In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment.The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP) layers where in each layer the sound speed is linearly related to the depth.Furthermore, each sensor node is able to measure its depth and can exchange this information with other nodes.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, The Netherlands. h.mashhadiramezani@tudelft.nl

ABSTRACT
In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment. The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP) layers where in each layer the sound speed is linearly related to the depth. Furthermore, each sensor node is able to measure its depth and can exchange this information with other nodes. Under these assumptions, we first show how the problem of underwater localization can be converted to the traditional range-based terrestrial localization problem when the depth information of the nodes is known a priori. Second, we relate the pair-wise time of flight (ToF) measurements between the nodes to their positions. Next, based on this relation, we propose a novel ranging algorithm for an underwater medium. The proposed ranging algorithm considers reflections from the seabed and sea surface. We will show that even without any reflections, the transmitted signal may travel through more than one path between two given nodes. The proposed algorithm analyzes them and selects the fastest one (first arrival path) based on the measured ToF and the nodes' depth measurements. Finally, in order to evaluate the performance of the proposed algorithm we run several simulations and compare the results with other existing algorithms.

No MeSH data available.


Related in: MedlinePlus