Using object to align and calibrate inertial navigation system
First Claim
1. A method comprising:
- capturing an image of an object with a camera in a mobile platform while stationary, the mobile platform having an inertial navigation system including inertial sensors, wherein an orientation between the inertial sensors and the camera is known;
obtaining position and orientation information of the object in a global reference frame;
estimating a position and orientation of the camera relative to the object from the image of the object;
determining a camera position and orientation in the global reference frame from the estimated position and orientation of the camera relative to the object and the obtained position and orientation of the object in the global reference frame;
determining with a processor a transformation matrix between a navigation coordinate frame and an inertial sensor reference frame for the inertial navigation system using the determined camera position and orientation in the global reference frame and the orientation between the inertial sensors and the camera, wherein determining the transformation matrix between the navigation coordinate frame and the inertial sensor reference frame comprises using a determined first transformation matrix between a camera reference frame and an object reference frame and a second transformation matrix between the global reference frame and the object reference frame;
setting a velocity of the inertial navigation system to zero;
setting the position of the inertial navigation system to the estimated position of the camera in the global reference frame;
using measurements from the inertial sensors, the determined transformation matrix, the set velocity and the set position of the inertial navigation system to update the inertial navigation system position, velocity, and orientation; and
providing the updated estimate of the position of the inertial navigation system as a position of the mobile platform.
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Abstract
The initialization of an inertial navigation system is performed using information obtained from an image of an object. Positional and orientational information about the object in a global reference frame and positional and orientational information about the camera relative to the object are obtained from the image. Positional and orientational information for the camera in the global reference frame is determined along with a transformation matrix between inertial sensor reference frame and a navigation coordinate frame. The inertial navigation system is initialized using the positional and orientational information for the camera, the transformation matrix and the velocity of the camera when the object was imaged, i.e., zero. Using the initialized data with measurements from the inertial sensors the position of the mobile platform may be updated during navigation and provided, e.g., on a digital map. Inertial navigation errors may be corrected using information obtained from images of different objects.
60 Citations
25 Claims
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1. A method comprising:
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capturing an image of an object with a camera in a mobile platform while stationary, the mobile platform having an inertial navigation system including inertial sensors, wherein an orientation between the inertial sensors and the camera is known; obtaining position and orientation information of the object in a global reference frame; estimating a position and orientation of the camera relative to the object from the image of the object; determining a camera position and orientation in the global reference frame from the estimated position and orientation of the camera relative to the object and the obtained position and orientation of the object in the global reference frame; determining with a processor a transformation matrix between a navigation coordinate frame and an inertial sensor reference frame for the inertial navigation system using the determined camera position and orientation in the global reference frame and the orientation between the inertial sensors and the camera, wherein determining the transformation matrix between the navigation coordinate frame and the inertial sensor reference frame comprises using a determined first transformation matrix between a camera reference frame and an object reference frame and a second transformation matrix between the global reference frame and the object reference frame; setting a velocity of the inertial navigation system to zero; setting the position of the inertial navigation system to the estimated position of the camera in the global reference frame; using measurements from the inertial sensors, the determined transformation matrix, the set velocity and the set position of the inertial navigation system to update the inertial navigation system position, velocity, and orientation; and providing the updated estimate of the position of the inertial navigation system as a position of the mobile platform. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A mobile platform comprising:
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a camera being operable to image an object; an inertial navigation system comprising inertial sensors that provides motion and rotation data; a processor connected to the camera and the inertial sensors; memory connected to the processor; and software held in the memory and run in the processor to cause the processor to obtain position and orientation information about the object in a global reference frame, estimate a position and orientation of the camera relative to the object from an image of the object taken by the camera;
determine a camera position and orientation in the global reference frame from the estimated position and orientation and the obtained position and orientation of the object in the global reference frame;
determine a transformation matrix between a navigation coordinate frame and an inertial sensor reference frame for the inertial navigation system using the determined camera position and orientation in the global reference frame and a known orientation between the inertial sensors and the camera, wherein the software causes the processor to determine a first transformation matrix between a camera reference frame and an object reference frame and a second transformation matrix between the global reference frame and the object reference frame to determine the transformation matrix between the navigation coordinate frame and the inertial sensor reference frame;
initializing the inertial navigation system with a velocity of zero, the determined position of the camera in the global reference frame and the determined transformation matrix between the navigation coordinate frame and the inertial sensor reference frame;
using data from the inertial sensors and the initialized velocity, position and transformation matrix to update the inertial navigation system position;
providing the updated inertial navigation system position as a position of the mobile platform; andwherein the software causes the processor to determine a first transformation matrix between a camera reference frame and an object reference frame and a second transformation matrix between the global reference frame and the object reference frame to determine the transformation matrix between the navigation coordinate frame and the inertial sensor reference frame. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A system for accessing and updating positional information for a mobile platform comprising:
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a means for imaging an object; means for obtaining position and orientation information about the object in a global reference frame; means for estimating a position and orientation of the means for imaging relative to the object from the image of the object; means for determining a position and orientation of the means for imaging in the global reference frame from the estimated position and orientation and the obtained position and orientation of the object; means for sensing movement of the mobile platform; means for determining a transformation matrix between a navigation coordinate frame and a frame for the means for sensing movement using the determined position and orientation of the means for imaging and a known orientation between the frame for the means for sensing movement and the means for imaging, wherein the means for determining the transformation matrix uses a first transformation matrix between a frame for the means for imaging and an object reference frame and a second transformation matrix between the global reference frame and the object reference frame; means for initializing an inertial navigation system with a velocity of zero, the determined position of the means for imaging and the determined transformation matrix between the navigation coordinate frame and the frame for the means for sensing movement; means for determining a position, velocity, and orientation of the mobile platform using the data from the means for sensing movement, and the initialized velocity, position, and transformation matrix; and means for providing the determined position of the mobile platform. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A non-transitory computer-readable medium including program code stored thereon, comprising:
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program code to decode and obtain position and orientation information in a global reference frame about an object that is imaged; program code to estimate a position and orientation from an image of the object; program code to determine a position and orientation in the global reference frame from the estimated position and orientation and the obtained position and orientation information in the global reference frame about the imaged object; program code to determine a transformation matrix between a navigation coordinate frame and a frame for inertial sensors of an inertial navigation system using the determined position and orientation in the global reference frame and a known orientation between the frame for the inertial sensors and a frame for a camera that produced the image of the object, wherein the program code to determine the transformation matrix uses a first transformation matrix between a frame for the means for imaging and an object reference frame and a second transformation matrix between the global reference frame and the object reference frame; program code to initialize the inertial navigation system using the determined position and orientation, the determined transformation matrix and a velocity of zero; program code to determine an updated position using the initialized position, transformation matrix, velocity and data from the inertial sensors; and program code to provide the updated position. - View Dependent Claims (25)
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Specification