US6549853B2
Expired / Lapsed
US
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Method for determining seafloor roughness using multibeam echosounder
Assignee: Council of Scientific and Industrial Research
•
Filing: 2001-03-22
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Granted: 2003-04-15
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Expires: 2021-03-22
Abstract
Abstract The present invention provides a method for determining sea floor roughness using multibeam echosounder, said method comprising providing backscatter, bathymetry and multibeam operational parameters; removing system gain from the backscatter data to obtain real seafloor backscatter data; calculating across track seafloor slope; incorporating correction factor in actual beam arrival angles; calculating seafloor area; measuring backscatter strength; obtaining backscatter strength data at 1° angle; obtaining power law parameters; using the above-obtained parameters in a seafloor roughness power law model; splicing the multibeam backscatter data; including sediment volume roughness model; and verifying the validity of the composite roughness model.
Inventors
- 👤 Bishwajit Chakraborty
- 👤 Vijay N. Kodagali
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:29
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/28; G01V1/38; G01V2210/00; G01V2210/50; G01V2210/58
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
106 words
A method for determining sea floor roughness using multibeam echosounder, comprising the steps of: i. providing backscatter, bathymetry and multibeam operational parameters; ii. removing system; gain from the backscatter data to obtain real seafloor backscatter data; iii. calculating across track seafloor slope; iv. incorporating correction factor in actual beam arrival angles; v. calculating seafloor area; vi. measuring backscatter strength; vii. obtaining backscatter strength data at 1° angle; viii. obtaining power; law parameters; ix. using the above-obtained parameters in a seafloor roughness power law model; x. splicing the multibeam backscatter data; xi. including sediment volume roughness model; and xii. verifying the validity of the composite roughness model.
Claim 2
Independent Claim
106 words
A method for determining sea floor roughness using multibeam echosounder, comprising the steps of: i. providing backscatter, bathymetry and multibeam operational parameters; ii. removing system; gain from the backscatter data to obtain real seafloor backscatter data; iii. calculating across track seafloor slope; iv. incorporating correction factor in actual beam arrival angles; v. calculating seafloor area; vi. measuring backscatter strength; vii. obtaining backscatter strength data at 1° angle; viii. obtaining power; law parameters; ix. using the above-obtained parameters in a seafloor roughness power law model; x. splicing the multibeam backscatter data; xi. including sediment volume roughness model; and xii. verifying the validity of the composite roughness model.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1 , wherein the primary backscatter parameters recorded by the system are echo rms voltage and signal duration for each beam.
Claim 4
Dependent Claim
19 words
A method as claimed in claim 1 , wherein the across track seafloor slope is calculated using bathymetry data.
Claim 5
Dependent Claim
25 words
A method as claimed in claim 1 , wherein the across track seafloor slope is calculated to incorporate correction factor in actual beam arrival angles.
Claim 6
Dependent Claim
33 words
A method as claimed in claim 1 , wherein the bottom slope values with respect to each beams are computed using tangent inverse of the ratio bet ween depth and lateral distance difference.
Claim 7
Dependent Claim
21 words
A method as claimed in claim 1 , wherein the seafloor area is calculated based upon angle of incidence and bathymetry.
Claim 8
Dependent Claim
32 words
A method as claimed in claim 1 , wherein the bottom sea surface area is calculated using the formula: A=A b exp[−(φ/φ x ) 2 ]+A p {1−exp[−(φ/φ x ) 2 ]}.
Claim 9
Dependent Claim
45 words
A method as claimed in claim 1 , wherein the actual echo root mean square level is calculated using DeMoustier and Alexandrou Formula: <20 log 10 RL (φ)>= SL +<10 log 10 S B (φ)>−40*log 10 ( R )−2α b R +10 log 10 A.
Claim 10
Dependent Claim
38 words
A method as claimed in claim 1 , wherein the backscatter strength data at 1° angle is obtained by bining each beam at 1° angular bins and averaging the number of samples in each bin for steady areas.
Claim 11
Dependent Claim
27 words
A method as claimed in claim 1 , wherein the power law parameters are obtained by reading the measured backscatter data and subjecting it to curve fitting.
Claim 12
Dependent Claim
20 words
A method as claimed in claim 1 , wherein Helmholtz-Kirchhoff approximation is used to determine interface roughness of the seabed.
Claim 13
Dependent Claim
18 words
A method as claimed in claim 1 , wherein the splicing is done using Helmholtz-Kirchoff and Rayleigh-Rice theories.
Claim 14
Dependent Claim
18 words
A method as claimed in claim 1 , wherein the incidence angle of 20° is used for splicing.
Claim 15
Dependent Claim
25 words
A method as claimed in claim 1 , wherein the sediment volume roughness model is created by curve fitting the entire measured angular backscatter data.
Claim 16
Dependent Claim
23 words
A method as claimed in claim 1 , wherein the verification is done by matching the theoretical curve with the measured backscatter data.
References Cited (Backward Citations)
US4232380A
Cited
US5485432A
Cited
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