Compensation of Magnetic Data for Autonomous Underwater Vehicle Mapping Surveys

• US 20160097875A1
• Filed: 09/21/2015
• Published: 04/07/2016
• Est. Priority Date: 10/01/2014
• Status: Active Grant

• Current Assignee: Ocean Floor Geophysics, Inc.
• Original Assignee: Ocean Floor Geophysics, Inc.
• Inventors: Kowalczyk, Peter
• Granted Patent: US 10,132,956 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B63G 2008/004 autonomously operating
• CPC Class Codes: B63G 8/001 Underwater vessels adapted for special purposes, e.g. unmanned underwater vessels; Equipment specially adapted therefor, e.g. docking stations self-propelled or direction controlled diving chambers with mechanical link to a base B63C11/42
• CPC Class Codes: B63G 8/34 Camouflage for other vessels B63G13/02; in general F41H3/00
• CPC Class Codes: B63H 23/00 Transmitting power from propulsion power plant to propulsive elements adaptation of transmission to allow adjustment in direction of propellers B63H5/125; transmission between wind motors and propulsive elements B63H13/00; in outboard propulsion units B63H20/14; adaptation of transmission to allow adjustment of location of propellers B63H20/08
• CPC Class Codes: G01V 3/165 operating with magnetic or electric fields produced or modified by the object or by the detecting device with electromagnetic waves G01V3/17
• CPC Class Codes: G01V 3/38 Processing data, e.g. for analysis, for interpretation, for correction
• CPC Class Codes: G01V 3/40 specially adapted for measuring magnetic field characteristics of the earth
• CPC Class Codes: G05D 1/048 specially adapted for water vehicles

Abstract

Embodiments of the present invention are generally related to compensation of magnetic data, and, in particular, to a system and method for compensation of magnetic data as collected during autonomous underwater vehicle mapping surveys.

Claims

1. A method for magnetic data compensation comprising:

providing at least one magnetometer mounted on a subsea vehicle;

maneuvering the subsea vehicle at a first altitude above the seafloor and a first heading;

receiving, by a microprocessor, a first set of raw output from the magnetometer;

receiving, by a microprocessor, subsea vehicle state data and subsea vehicle performance data concurrently with the receiving of the first set of raw magnetic data; and

processing, by a microprocessor, the subsea vehicle state data, the subsea vehicle performance data, and the first set of raw magnetic data to produce magnetic compensation coefficients.

2. The method of claim 1, wherein the produced compensated magnetic data references a frame of reference comprising the magnetometer and the subsea vehicle.

3. The method of claim 1, wherein the processing is independent of an ambient magnetic field.

4. The method of claim 1, wherein the produced compensated magnetic data does not reference the Earth'"'"'s geodetic frame of reference.

5. The method of claim 1, further comprising performing a subsea mapping and receiving a second set of raw magnetic data output from the magnetometer while performing the subsea mapping.

6. The method of claim 5, further comprising applying the magnetic compensation coefficients to the second set of raw magnetic data to produce compensated magnetic survey data.

7. The method of claim 1, further comprising maneuvering the subsea vehicle at a second altitude above the seafloor at the first heading.

8. The method of claim 5, further comprising maneuvering the subsea vehicle at a second altitude above the seafloor, wherein the subsea mapping is performed at a survey altitude above the seafloor, the survey altitude between and including the first altitude and the second altitude.

9. The method of claim 1, further comprising maneuvering the subsea vehicle at a second altitude above the seafloor at a second heading.

10. The method of claim 1, further comprising maneuvering the subsea vehicle at a first altitude above the seafloor at a heading 180 degrees from the first heading.

11. The method of claim 1, wherein the manuvering step comprises tracing a rectangular seafloor heading track.

12. The method of claim 1, wherein the subsea vehicle state data comprises depth and altitude above the seafloor.

13. The method of claim 1, wherein the subsea vehicle performance data comprises variable thruster motor currents.

14. The method of claim 1, wherein the subsea vehicle comprises an ROV and an AUV.

21. A tangible and non-transient computer readable medium comprising microprocessor executable instructions that, when executed, perform the receiving and processing steps of claim 1.

22. A system comprising a microprocessor that performs the receiving and processing steps of claim 1.

15. A method to produce compensated magnetic underwater survey data comprising:

providing at least one magnetometer mounted on a subsea vehicle;

maneuvering the subsea vehicle at a first altitude above the seafloor and a first heading, and at a second altitude above the seafloor at a heading 180 degrees from the first heading;

receiving, by a microprocessor, a first set of raw output from the magnetometer;

receiving, by a microprocessor, subsea vehicle state data and subsea vehicle performance data concurrently with the receiving of the first set of raw magnetic data;

processing, by a microprocessor, the subsea vehicle state data, the subsea vehicle performance data, and the first set of raw magnetic data to produce magnetic compensation coefficients;

performing a subsea mapping and receiving a second set of raw magnetic data output from the magnetometer while performing the subsea mapping; and

applying, by a microprocessor, the magnetic compensation coefficients to the second set of raw magnetic data to produce compensated magnetic survey data which does not reference the Earth'"'"'s geodetic frame of reference;

wherein the subsea vehicle performance data comprises variable thruster motor currents;

wherein the subsea vehicle state data comprises depth and altitude above the seafloor.

23. A tangible and non-transient computer readable medium comprising microprocessor executable instructions that, when executed, perform the receiving, processing, and applying steps of claim 15.

24. A system comprising a microprocessor that performs the receiving, processing, and applying steps of claim 15.

16. A system to produce compensated magnetic underwater survey data comprising:

at least one magnetometer configured to mount to a subsea vehicle;

a non-transitory computer readable medium;

a processor in communication with the non-transitory computer readable medium, the processor operable to;

receive a first set of raw output from the magnetometer;

receive subsea vehicle state data and subsea vehicle performance data concurrently with the receiving of the first set of raw magnetic data;

processing the subsea vehicle state data, the subsea vehicle performance data, and the first set of raw magnetic data to produce magnetic compensation coefficients;

receiving a second set of raw magnetic data output from the magnetometer while performing the subsea mapping;

applying the magnetic compensation coefficients to the second set of raw magnetic data to produce compensated magnetic survey data;

wherein the first set of state data is collected while the subsea vehicle maneuvers at a first altitude above the seafloor and a first heading;

wherein the second set of raw magnetic data is collected while the subsea vehicle is performing a subsea mapping.

17. The system of claim 16, wherein the produced compensated magnetic data references a frame of reference comprising the magnetometer and the subsea vehicle.

18. The system of claim 16, wherein the processing is independent of an ambient magnetic field.

19. The system of claim 16, wherein the subsea vehicle state data comprises depth and altitude above the seafloor.

20. The system of claim 16, wherein the subsea vehicle performance data comprises variable thruster motor currents.