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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

Performance of the proposed algorithm for difference values of noise power.
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f11-sensors-12-02996: Performance of the proposed algorithm for difference values of noise power.

Mentions: In Figure 11, we investigate the effect of the measurement noise on the algorithms under consideration. Here the depth of the two nodes is as before, and their horizontal range is fixed at 3 km. The horizontal axis represents how noisy the measured data are. The depth and ToF measurement noise powers are exponentially related to the parameter λ, i.e., σz = 103σt = 102−λ. It can be seen that, the performance of the proposed ranging algorithm constantly improves and attains the CRB when we increase the measurement accuracy, while the straight-line estimation does not show any improvement after a given noise power.


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

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

Performance of the proposed algorithm for difference values of noise power.
© Copyright Policy
Related In: Results  -  Collection

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

f11-sensors-12-02996: Performance of the proposed algorithm for difference values of noise power.
Mentions: In Figure 11, we investigate the effect of the measurement noise on the algorithms under consideration. Here the depth of the two nodes is as before, and their horizontal range is fixed at 3 km. The horizontal axis represents how noisy the measured data are. The depth and ToF measurement noise powers are exponentially related to the parameter λ, i.e., σz = 103σt = 102−λ. It can be seen that, the performance of the proposed ranging algorithm constantly improves and attains the CRB when we increase the measurement accuracy, while the straight-line estimation does not show any improvement after a given noise power.

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