Ship inertial navigation equipment position and posture calibration method based on two-dimensional code scanning

Abstract

The application discloses a ship inertial navigation equipment position and posture calibration method based on two-dimensional code scanning, and comprises the following steps: printing a positioning two-dimensional code on a plane mirror, and installing the plane mirror on a bow and stern line of a ship deck or a GNSS antenna position; installing a high-precision camera and calibrating to obtain an installation deflection angle between the inertial navigation equipment and the high-precision camera, so as to obtain a coordinate conversion matrix between the inertial navigation equipment and the high-precision camera; obtaining a corresponding position and posture relationship between the two through the high-precision camera shooting of the two-dimensional code, so as to obtain a coordinate conversion matrix between the two-dimensional code and the high-precision camera; calculating a posture transfer matrix between the inertial navigation equipment and the two-dimensional code, so as to calculate an installation deflection angle between the inertial navigation equipment and the bow and stern line of the ship; obtaining a distance between the high-precision camera and the two-dimensional code through the high-precision camera shooting of the two-dimensional code, and then calculating an outer lever arm value of the two-dimensional code relative to the inertial navigation equipment. The application has wider applicability.

Description

Technical Field

[0001] This invention relates to the field of marine equipment, and in particular to a method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning. Background Technology

[0002] The calibration of installation errors in marine inertial navigation systems (INS) has long been a challenging problem. Most marine INS calibrations require the use of gyrotheodolites or optical equipment and prisms. A gyrotheodolite is an instrument that combines a gyroscope and a theodolite through a connecting mechanism to determine true north azimuth. It utilizes the physical characteristics of the gyroscope itself (fixed axis and precession), employing a metal belt to suspend the gyro's sensitive part, which has its center of gravity lowered, to sense the horizontal component of the Earth's rotational angular velocity. Under the influence of gravity, this generates a northward precession torque, causing the gyroscope's main axis to oscillate back and forth around the Earth's meridian, thus determining the true north azimuth. Gyrotheodolites are typically only usable in static conditions; for ship calibration, this process must be carried out in a dry dock, which presents certain limitations. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning. By utilizing a high-precision camera and visual QR codes, it can meet the calibration requirements of ship inertial navigation equipment under both static and non-static conditions, thus having a wider range of applications.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] A method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning, the method comprising the following steps:

[0006] Step 1, Plane Mirror Installation: Print the positioning QR code onto the plane mirror and install the plane mirror on the bow-stern line of the ship's deck;

[0007] Step 2, High-precision camera installation: Install the high-precision camera on the ship's inertial navigation equipment. Using the side plane of the ship's inertial navigation equipment as the reference plane, align the mounting surface of the high-precision camera with the reference plane. Establish a coordinate system with the horizontal plane as the X-axis, the vertical plane as the Y-axis, the vertical direction as the Z-axis, and the center of the side of the ship's inertial navigation equipment as the origin. Calibrate in the laboratory to obtain the installation deflection angle between the ship's inertial navigation equipment and the high-precision camera. Obtain the coordinate transformation matrix between the ship's inertial navigation equipment and the high-precision camera based on the installation deflection angle.

[0008] Step 3, calculate the coordinate transformation matrix: By taking a picture of the QR code on the plane mirror with a high-precision camera, obtain the corresponding position and orientation relationship between the high-precision camera and the QR code on the plane mirror, and then calculate the coordinate transformation matrix between the QR code on the plane mirror and the high-precision camera.

[0009] Step 4, Calibrate the installation deflection angle: Calculate the attitude transfer matrix between the ship's inertial navigation equipment and the QR code on the plane mirror, thereby calculating the installation deflection angle between the ship's inertial navigation equipment and the ship's bow and stern lines, and completing the installation calibration of the ship's inertial navigation equipment.

[0010] A method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning, the method comprising the following steps:

[0011] Step S1, Plane Mirror Installation: Print the positioning QR code onto the plane mirror and install the plane mirror at the GNSS antenna location;

[0012] Step S2, High-precision camera installation: Install a high-precision camera on the ship's inertial navigation equipment. Using the side plane of the ship's inertial navigation equipment as the reference plane, align the mounting surface of the high-precision camera with the reference plane. Establish a coordinate system with the horizontal plane as the X-axis, the vertical plane as the Y-axis, the vertical direction as the Z-axis, and the center of the side of the ship's inertial navigation equipment as the origin. Calibrate in the laboratory to obtain the installation deflection angle between the ship's inertial navigation equipment and the high-precision camera. Obtain the coordinate transformation matrix between the ship's inertial navigation equipment and the high-precision camera based on the installation deflection angle.

[0013] Step S3, calculate the coordinate transformation matrix: capture the QR code on the plane mirror with a high-precision camera, obtain the corresponding position and orientation relationship between the high-precision camera and the QR code on the plane mirror, and thus calculate the coordinate transformation matrix between the QR code on the plane mirror and the high-precision camera.

[0014] Step S4, calibrate the external boom value: Take a picture of the QR code on the plane mirror with a high-precision camera to obtain the distance between the high-precision camera and the QR code on the plane mirror. Then, based on the attitude transfer matrix between the ship's inertial navigation equipment and the QR code on the plane mirror, calculate the external boom value of the QR code on the plane mirror relative to the ship's inertial navigation equipment.

[0015] Furthermore, the installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the X-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Y-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Z-axis direction is... The coordinate transformation matrix between the ship's inertial navigation equipment coordinate system and the high-precision camera is:

[0016] .

[0017] Furthermore, the corresponding position and orientation relationship between the high-precision camera and the QR code on the plane mirror follows the formula below:

[0018] ,

[0019] Where s is the pixel coordinate. Let be the projected coordinates of the i-th target point on the image plane. Let H be the coordinates of the i-th target point, and H be the coordinate mapping matrix.

[0020] Expanding the above formula, we get:

[0021] ,

[0022] The elements of the H matrix can be obtained by using information from multiple target points and the least squares method.

[0023] Then, by normalizing the H matrix, the coordinate transformation matrix T between the QR code on the plane mirror and the high-precision camera can be obtained:

[0024] .

[0025] Furthermore, the attitude transfer matrix between the ship's inertial navigation equipment and the QR code on the plane mirror. The calculation formula is as follows:

[0026] .

[0027] Furthermore, the projection of the QR code on the plane mirror relative to the position of the high-precision camera in the X, Y, and Z axes follows the formula:

[0028] ,

[0029] Where L is the distance between the high-precision camera and the QR code on the plane mirror. The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the X-axis direction; The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the Y-axis direction is [value missing]. The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the Z-axis direction is denoted by the QR code.

[0030] Based on the above technical solution, this application has the following advantages compared with the prior art:

[0031] 1. This application involves placing several QR codes fixedly along the bow and stern lines of a ship, then using a high-precision camera to acquire images of the QR codes. After relevant calculations, the attitude and heading angle of the high-precision camera relative to the QR codes are obtained, thereby obtaining the installation error of the ship's inertial navigation equipment. This calibration method differs from gyro theodolites, which can only be calibrated under static conditions, and is not limited to implementation in a dock, thus having a wider range of applicability.

[0032] 2. This application obtains the external boom value of the ship's inertial navigation equipment, i.e., the position information of the ship's inertial navigation equipment relative to the GNSS antenna, by placing a QR code at the GNSS antenna location, acquiring the QR code image with a high-precision camera, and performing data calculation. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the plane mirror installation position in an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram illustrating the working principle of the present invention.

[0035] Figure 3 This is a diagram showing the installation relationship between the ship's inertial navigation equipment, camera, and QR code in this invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments are shown below to describe the present invention. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the present invention. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concept of the present invention.

[0037] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0038] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be construed as indicating or implying relative importance. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0039] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical connection or internal connection between two components. They can be direct connection or indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0040] To better understand the technical solution of the present invention, the following detailed description is provided in conjunction with specific embodiments. The embodiments described below are only for explaining the present invention and are not intended to limit the present invention. Specific experimental methods not mentioned in the embodiments are generally performed according to conventional experimental methods. Unless otherwise specified, all instruments used are commercially available conventional products.

[0041] Example 1: A method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning. The method includes the following steps:

[0042] Step 1, plane mirror installation: Print the positioning QR code onto several plane mirrors and install the plane mirrors on the bow and stern lines of the ship's deck;

[0043] Step Two, High-Precision Camera Installation: Install the high-precision camera on the ship's inertial navigation system. Using the side plane of the ship's inertial navigation system as the reference plane, align the mounting surface of the high-precision camera with the reference plane. Establish a coordinate system with the horizontal direction as the X-axis, the vertical direction as the Y-axis, the vertical direction as the Z-axis, and the center of the side of the ship's inertial navigation system as the origin. Calibrate in the laboratory to obtain the installation deflection angle between the ship's inertial navigation system and the high-precision camera. Based on the installation deflection angle, obtain the coordinate transformation matrix between the ship's inertial navigation system and the high-precision camera. The installation deflection angle between the ship's inertial navigation system and the high-precision camera in the X-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Y-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Z-axis direction is... The coordinate transformation matrix between the ship's inertial navigation equipment coordinate system and the high-precision camera is:

[0044] ,

[0045] Step 3, Calculate the coordinate transformation matrix: By photographing the QR code on the plane mirror with a high-precision camera, the corresponding position and orientation relationship between the high-precision camera and the QR code on the plane mirror is obtained. This allows us to calculate the coordinate transformation matrix between the QR code on the plane mirror and the high-precision camera. The corresponding position and orientation relationship between the high-precision camera and the QR code on the plane mirror follows the formula below:

[0046] ,

[0047] Where s is the pixel coordinate. Let be the projected coordinates of the i-th target point on the image plane. Let H be the coordinates of the i-th target point, and H be the coordinate mapping matrix.

[0048] Expanding the above formula, we get:

[0049] ,

[0050] The elements of the H matrix can be obtained by using information from multiple target points and the least squares method.

[0051] Then, by normalizing the H matrix, the coordinate transformation matrix T between the QR code on the plane mirror and the high-precision camera can be obtained:

[0052] .

[0053] Attitude transfer matrix between the ship's inertial navigation equipment and the QR code of the plane mirror The calculation formula is as follows:

[0054] ,

[0055] Step 4, Calibrate the installation deflection angle: Calculate the attitude transfer matrix between the ship's inertial navigation equipment and the QR code on the plane mirror, thereby calculating the installation deflection angle between the ship's inertial navigation equipment and the ship's bow and stern lines, and completing the installation calibration of the ship's inertial navigation equipment.

[0056] Example 2: A method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning, the method comprising the following steps:

[0057] Step S1, Plane Mirror Installation: Print the positioning QR code onto several plane mirrors and install the plane mirrors at the GNSS antenna location;

[0058] Step S2, High-precision camera installation: Install a high-precision camera on the ship's inertial navigation equipment. Using the side plane of the ship's inertial navigation equipment as the reference plane, align the mounting surface of the high-precision camera with the reference plane. Establish a coordinate system with the horizontal plane as the X-axis, the vertical plane as the Y-axis, the vertical direction as the Z-axis, and the center of the side of the ship's inertial navigation equipment as the origin. Calibrate in the laboratory to obtain the installation deflection angle between the ship's inertial navigation equipment and the high-precision camera. Obtain the coordinate transformation matrix between the ship's inertial navigation equipment and the high-precision camera based on the installation deflection angle.

[0059] Step S3, calculate the coordinate transformation matrix: capture the QR code on the plane mirror with a high-precision camera, obtain the corresponding position and orientation relationship between the high-precision camera and the QR code on the plane mirror, and thus calculate the coordinate transformation matrix between the QR code on the plane mirror and the high-precision camera.

[0060] Step S4, calibrate the external boom value: Take a picture of the QR code on the plane mirror with a high-precision camera to obtain the distance between the high-precision camera and the QR code on the plane mirror. Then, based on the attitude transfer matrix between the ship's inertial navigation equipment and the QR code on the plane mirror, calculate the external boom value of the QR code on the plane mirror relative to the ship's inertial navigation equipment.

[0061] Let the installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the X-axis direction be . The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Y-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Z-axis direction is... The coordinate transformation matrix between the ship's inertial navigation equipment coordinate system and the high-precision camera is:

[0062] ,

[0063] Therefore, the corresponding position and orientation relationship between the high-precision camera and the QR code on the plane mirror follows the formula:

[0064] ,

[0065] Where s is the pixel coordinate. Let be the projected coordinates of the i-th target point on the image plane. Let H be the coordinates of the i-th target point, and H be the coordinate mapping matrix.

[0066] Expanding the above formula, we get:

[0067] ,

[0068] The elements of the H matrix can be obtained by using information from multiple target points and the least squares method.

[0069] Then, by normalizing the H matrix, the coordinate transformation matrix T between the QR code on the plane mirror and the high-precision camera can be obtained:

[0070] .

[0071] Then, the attitude transfer matrix between the ship's inertial navigation equipment and the QR code on the plane mirror. The calculation formula is as follows:

[0072] .

[0073] Therefore, the projection of the QR code on the plane mirror relative to the position of the high-precision camera in the X, Y, and Z axes follows the formula:

[0074] ,

[0075] Where L is the distance between the high-precision camera and the QR code on the plane mirror. The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the X-axis direction; The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the Y-axis direction is [value missing]. The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the Z-axis direction is denoted by the QR code.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning, characterized in that, The method includes the following steps: Step 1, Plane Mirror Installation: Print the positioning QR code onto the plane mirror and install the plane mirror on the bow-stern line of the ship's deck; Step 2, High-precision camera installation: Install the high-precision camera on the ship's inertial navigation equipment. Using the side plane of the ship's inertial navigation equipment as the reference plane, align the mounting surface of the high-precision camera with the reference plane. Establish a coordinate system with the horizontal plane as the X-axis, the vertical plane as the Y-axis, the vertical direction as the Z-axis, and the center of the side of the ship's inertial navigation equipment as the origin. Calibrate in the laboratory to obtain the installation deflection angle between the ship's inertial navigation equipment and the high-precision camera. Obtain the coordinate transformation matrix between the ship's inertial navigation equipment and the high-precision camera based on the installation deflection angle. Step 3, Calculate the coordinate transformation matrix: By photographing the QR code on the plane mirror with a high-precision camera, the corresponding position and attitude relationship between the high-precision camera and the QR code on the plane mirror is obtained. This allows the calculation of the coordinate transformation matrix between the plane mirror's QR code and the high-precision camera. The installation angle of the ship's inertial navigation equipment relative to the high-precision camera in the X-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Y-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Z-axis direction is... The coordinate transformation matrix between the ship's inertial navigation equipment coordinate system and the high-precision camera is: ， The corresponding position and orientation relationship between the QR code on the high-precision camera and the plane mirror follows the formula below: ， in, For pixel coordinates, , Let be the projected coordinates of the i-th target point on the image plane. Let H be the coordinates of the i-th target point, and H be the coordinate mapping matrix. Expanding the above formula, we get: ， The elements of the H matrix can be obtained by using information from multiple target points and the least squares method. Then, by normalizing the H matrix, the coordinate transformation matrix T between the QR code on the plane mirror and the high-precision camera can be obtained: ； Step 4, Calibrate the installation deflection angle: Calculate the attitude transfer matrix between the ship's inertial navigation equipment and the QR code on the plane mirror, thereby calculating the installation deflection angle between the ship's inertial navigation equipment and the ship's bow and stern lines, and completing the installation calibration of the ship's inertial navigation equipment.

2. A method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning, characterized in that, The method includes the following steps: Step S1, Plane Mirror Installation: Print the positioning QR code onto the plane mirror and install the plane mirror at the GNSS antenna location; Step S2, High-precision camera installation: Install a high-precision camera on the ship's inertial navigation equipment. Using the side plane of the ship's inertial navigation equipment as the reference plane, align the mounting surface of the high-precision camera with the reference plane. Establish a coordinate system with the horizontal plane as the X-axis, the vertical plane as the Y-axis, the vertical direction as the Z-axis, and the center of the side of the ship's inertial navigation equipment as the origin. Calibrate in the laboratory to obtain the installation deflection angle between the ship's inertial navigation equipment and the high-precision camera. Obtain the coordinate transformation matrix between the ship's inertial navigation equipment and the high-precision camera based on the installation deflection angle. Step S3, Calculate the coordinate transformation matrix: By capturing the QR code on the plane mirror using a high-precision camera, the corresponding position and attitude relationship between the high-precision camera and the QR code on the plane mirror is obtained. This allows the calculation of the coordinate transformation matrix between the plane mirror's QR code and the high-precision camera. The installation angle of the ship's inertial navigation equipment relative to the high-precision camera in the X-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Y-axis direction is... The installation offset angle between the ship's inertial navigation equipment and the high-precision camera in the Z-axis direction is... The coordinate transformation matrix between the ship's inertial navigation equipment coordinate system and the high-precision camera is: ， The corresponding position and orientation relationship between the QR code on the high-precision camera and the plane mirror follows the formula below: ， in, For pixel coordinates, Let be the projected coordinates of the i-th target point on the image plane. Let H be the coordinates of the i-th target point, and H be the coordinate mapping matrix. Expanding the above formula, we get: ， The elements of the H matrix can be obtained by using information from multiple target points and the least squares method. Then, by normalizing the H matrix, the coordinate transformation matrix T between the QR code on the plane mirror and the high-precision camera can be obtained: ； Step S4, calibrate the external boom value: Take a picture of the QR code on the plane mirror with a high-precision camera to obtain the distance between the high-precision camera and the QR code on the plane mirror. Then, based on the attitude transfer matrix between the ship's inertial navigation equipment and the QR code on the plane mirror, calculate the external boom value of the QR code on the plane mirror relative to the ship's inertial navigation equipment.

3. A method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning according to claim 1 or 2, characterized in that, Attitude transfer matrix between the ship's inertial navigation equipment and the QR code of the plane mirror The calculation formula is as follows: 。 4. The method for calibrating the position and attitude of a ship's inertial navigation equipment based on QR code scanning according to claim 3, characterized in that, The projection of the QR code on the plane mirror relative to the position of the high-precision camera in the X, Y, and Z axes follows the formula: ， Where L is the distance between the high-precision camera and the QR code on the plane mirror. The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the X-axis direction; The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the Y-axis direction is [value missing]. The value of the outer arm of the plane mirror relative to the ship's inertial navigation equipment in the Z-axis direction is denoted by the QR code.

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