IUSBL installation error calibration method independent of fixed transponder and related equipment

Abstract

The invention provides an iUSBL installation error calibration method independent of a fixed transponder and related equipment, and relates to the technical field of inverse ultra-short baseline installation errors. The method comprises the following steps: step 1, calculating coordinates of a transponder in an iUSBL coordinate system according to iUSBL direction finding and distance measuring information; step 2, calculating an origin coordinate of an iUSBL coordinate system under a navigation coordinate system by using UUV position and attitude information provided by iUSBL distance measurement information assisted INS integrated navigation and a lever arm; 3, establishing a theoretical relational expression between the coordinates of the transponder and the coordinates of the origin of the iUSBL coordinate system; 4, establishing a difference equation according to the theoretical relational expression; and 5, based on the difference equation, establishing an objective function and calculating an iUSBL installation error parameter by adopting a nonlinear least square solution. According to the iUSBL installation error calibration method, iUSBL installation error calibration without fixing the transponder can be realized, and the applicability and the flexibility of the iUSBL installation error calibration method are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of inverse ultra short baseline (iUSBL) installation error, and in particular to an iUSBL installation error calibration method and related equipment that do not rely on a fixed transponder. Background Art

[0002] The inverse ultra-short baseline (iUSBL) positioning system is a new type of acoustic positioning system formed by the ultra-short baseline (USBL) positioning system through the change of working mode. The USBL positioning system is to install the acoustic transceiver on the surface mother ship and the transponder on the underwater target (such as an unmanned underwater vehicle); while the iUSBL positioning system is to install the acoustic transceiver on the underwater target and the transponder on the surface mother ship, GNSS buoy or seabed beacon. USBL installation error calibration is one of the main error sources affecting its positioning accuracy. Therefore, installation error calibration must be performed before actual use. Zheng Cui'e et al. introduced a two-step calibration method based on the least squares principle. First, the position of the fixed transponder on the seabed is estimated using the distance observation value, and then the installation error angle is estimated based on the mathematical relationship between the coordinates of the transponder in the USBL carrier coordinate system and the geodetic coordinate system. Chen H.H et al. proposed a calibration method based on circular and linear trajectories, the premise of which is that the position information of the transponder in the navigation coordinate system is known. Sun D et al. proposed a calibration method for the installation error angle, which uses matrix decomposition and iterative calculation to improve the calibration accuracy. Tong JW et al. studied the relationship between the USBL installation error angle and positioning accuracy, and verified that the horizontal error is mainly affected by the heading angle and roll angle errors. In addition, Tong JW et al. introduced an incremental calculation method in the calibration parameter estimation to improve the calculation efficiency. Yao Y et al. proposed an IMM (Interacting Multiple Model)-UKF (Unscented Kalman Filter)-assisted USBL installation error calibration scheme to improve the calibration efficiency and adaptability of the calibration method.

[0003] Although iUSBL positioning technology has received much attention in recent years, the problem of its installation error calibration has not been addressed in the open literature. Figure 1 (a) The iUSBL system in working mode can refer to the above USBL installation error calibration method to achieve its installation error calibration, in which only the unmanned underwater vehicle (UUV) is required to sail on the water surface; but Figure 1(b) The installation error calibration problem of the iUSBL system in working mode is still an important unresolved issue. Although the precision manufacturing of UUV can avoid installation errors, it will greatly increase the manufacturing cost of UUV. Therefore, how to avoid the dependence of installation error calibration on fixed transponders and directly use the transponders installed on the GNSS buoy (in a floating state) to realize iUSBL installation error calibration is a key issue that needs to be solved for the further development and promotion of iUSBL positioning technology. Summary of the invention

[0004] In order to solve the iUSBL installation error calibration problem when the transponder is located on the sea surface, the present invention provides an iUSBL installation error calibration method and related equipment that do not rely on a fixed transponder, which can realize iUSBL installation error calibration without a fixed transponder and improve the applicability and flexibility of the iUSBL installation error calibration method.

[0005] In a first aspect, the present invention provides an iUSBL installation error calibration method that does not rely on a fixed transponder, comprising:

[0006] Step 1: Calculate the coordinates of the transponder in the iUSBL coordinate system based on the iUSBL direction finding and ranging information;

[0007] Step 2: Use the iUSBL ranging information to assist the UUV position and attitude information provided by the INS integrated navigation, as well as the lever arm, to calculate the origin coordinates of the iUSBL coordinate system in the navigation coordinate system;

[0008] Step 3: Establish a theoretical relationship between the transponder coordinates and the origin coordinates of the iUSBL coordinate system;

[0009] Step 4: Establish a differential equation based on the theoretical relationship;

[0010] Step 5: Based on the differential equation, establish the objective function and use the nonlinear least squares solution method to calculate the iUSBL installation error parameters.

[0011] Furthermore, step 1 specifically includes:

[0012]

[0013] Among them, X T a represents the coordinates of the transponder center T in the iUSBL coordinate system a, R is the underwater acoustic ranging value, d is the array element spacing, λ is the acoustic wavelength, φ and are the phase differences of the received signals of adjacent array elements on the x-axis and y-axis respectively.

[0014] Furthermore, in step 2, the coordinates of the origin of the iUSBL coordinate system in the navigation coordinate system are:

[0015]

[0016] in, and They represent the position and attitude of the UUV in the navigation coordinate system n; △X i is the lever arm, which represents the position vector of the origin of the iUSBL coordinate system in the IMU coordinate system.

[0017] Further, in step 3, the theoretical relationship is:

[0018]

[0019] Where R represents the rotation matrix, its subscript represents the coordinate system to be transformed, and its superscript represents the target coordinate system; the superscripts n, i, and a represent the navigation coordinate system, the IMU coordinate system, and the iUSBL coordinate system, respectively; the subscripts T and A represent the center of the transponder and the origin of the iUSBL coordinate system, respectively; represents the coordinates of the transponder center T in the iUSBL coordinate system a, represents the known coordinates of the transponder center T in the navigation coordinate system n, Represents the origin coordinates of the iUSBL coordinate system in the navigation coordinate system n.

[0020] Furthermore, in step 4, the difference equation is:

[0021]

[0022] Wherein, subscript j=1,2,3,…,J represents the observation time.

[0023] Furthermore, in step 5, the objective function is:

[0024]

[0025] In a second aspect, the present invention provides an iUSBL installation error calibration system that does not rely on a fixed transponder, comprising:

[0026] A transponder coordinate calculation module, used to calculate the coordinates of the transponder in the iUSBL coordinate system according to the iUSBL direction-finding and distance-finding information;

[0027] The iUSBL coordinate system origin coordinate calculation module is used to use the iUSBL ranging information to assist the UUV position and attitude information provided by the INS integrated navigation, as well as the lever arm, to calculate the iUSBL coordinate system origin coordinates in the navigation coordinate system;

[0028] A coordinate relationship building module is used to establish a theoretical relationship between the transponder coordinates and the origin coordinates of the iUSBL coordinate system;

[0029] A difference equation building module, used for building a difference equation according to the theoretical relationship;

[0030] The installation error parameter calculation module is used to establish an objective function based on the differential equation and calculate the iUSBL installation error parameters using a nonlinear least squares solution.

[0031] In a third aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in the first aspect when executing the program.

[0032] In a fourth aspect, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method described in the first aspect.

[0033] Beneficial effects of the present invention:

[0034] The iUSBL installation error calibration method and system proposed by the present invention, which does not rely on a fixed transponder, not only helps to reduce costs and increase efficiency at the user end, but also supports the plug-and-play of the iUSBL system, eliminating a lot of preparation work before the use of the iUSBL positioning system, and can greatly improve the flexibility of the iUSBL system. In addition, the iUSBL installation error angle can be calculated separately, or the iUSBL installation error angle and the lever arm can be calculated simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the iUSBL system working principle: (a) transponder deployment mode on the seabed; (b) transponder deployment mode on small buoys on the sea surface;

[0036] Figure 2 A flowchart of an iUSBL installation error calibration method that does not rely on a fixed transponder provided by an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of the structure of an iUSBL installation error calibration system that does not rely on a fixed transponder provided by an embodiment of the present invention;

[0038] Figure 4 A structural block diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The relevant professional terms involved in the present invention are explained as follows:

[0041] IMU: (inertial measurement unit, inertial measurement unit;

[0042] INS: Inertial Navigation System, inertial navigation system.

[0043] The present invention utilizes the characteristic that the iUSBL installation error angle is essentially a single beacon ranging assisted IMU integrated navigation system before calibration, and uses the high-precision relative information of the iUSBL ranging information to assist the INS integrated navigation to establish the differential equation, thereby avoiding the influence of the UUV position and attitude accuracy problems discovered over time on the iUSBL installation error calibration.

[0044] To facilitate the description of the technical solution of the present invention, in the present invention, the superscripts n, i and a respectively represent the navigation coordinate system, the IMU carrier coordinate system (referred to as the IMU coordinate system) and the iUSBL carrier coordinate system (referred to as the iUSBL coordinate system); the subscripts T, I and A respectively represent the transponder center and the origin of the IMU and iUSBL coordinate systems.

[0045] like Figure 2 As shown, an iUSBL installation error calibration method that does not rely on a fixed transponder provided by an embodiment of the present invention includes the following steps:

[0046] S101: Calculate the coordinates of the transponder in the iUSBL coordinate system according to the iUSBL direction finding and distance finding information; as shown in formula (1):

[0047]

[0048] in, represents the coordinates of the transponder center T in the iUSBL coordinate system a; R is the underwater acoustic ranging value, which can be calculated based on the time delay and sound speed. Generally, the sound line bending correction should be performed; d is the array element spacing, λ is the sound wave wavelength, φ and are the phase differences of the signals received by adjacent array elements on the x-axis and y-axis respectively.

[0049] S102: Using iUSBL ranging information to assist the UUV position provided by INS integrated navigation and posture and the lever arm △X i , calculate the origin coordinates of the iUSBL coordinate system in the navigation coordinate system; as shown in formula (2):

[0050]

[0051] Among them, △X i is the lever arm, which represents the position vector of the origin of the iUSBL coordinate system in the IMU coordinate system and can be directly measured.

[0052] S103: Establish a theoretical relationship between the transponder coordinates and the origin coordinates of the iUSBL coordinate system; as shown in formula (3):

[0053]

[0054] Where R represents the rotation matrix, its subscript represents the coordinate system to be transformed, and its superscript represents the target coordinate system; represents the coordinates of the transponder center T in the iUSBL coordinate system a, represents the known coordinates of the transponder center T in the navigation coordinate system n, Represents the origin coordinates of the iUSBL coordinate system in the navigation coordinate system n.

[0055] S104: According to the theoretical relationship, the difference equation is established by taking advantage of the small relative error between adjacent epochs of the iUSBL ranging information-assisted INS integrated navigation result; as shown in formula (4):

[0056]

[0057] Where, the subscript j = 1, 2, 3, ..., J represents the observation time. Since the relative errors of position and attitude between adjacent epochs are very small, the differential equation can greatly weaken the influence of low accuracy of UUV position and attitude, that is, and The impact of error divergence.

[0058] S105: Based on the differential equation, establish an objective function as shown in formula (5) and use a nonlinear least squares solution to calculate the iUSBL installation error parameters.

[0059]

[0060] Specifically, the objective function shown in formula (5) is a typical nonlinear least squares problem, so a nonlinear least squares solution (such as the Gauss-Newton method or the gradient descent method) is used to calculate the optimal solution of the iUSBL installation error parameter.

[0061] Corresponding to the above method, such as Figure 3 As shown, an embodiment of the present invention also provides an iUSBL installation error calibration system that does not rely on a fixed transponder, including a transponder coordinate calculation module, an iUSBL coordinate system origin coordinate calculation module, a coordinate relationship construction module, a differential equation construction module and an installation error parameter calculation module.

[0062] Among them, the transponder coordinate calculation module is used to calculate the coordinates of the transponder in the iUSBL coordinate system according to the iUSBL direction finding and ranging information; the iUSBL coordinate system origin coordinate calculation module is used to use the iUSBL ranging information to assist the UUV position and attitude information provided by the INS integrated navigation, as well as the lever arm, to calculate the coordinates of the iUSBL coordinate system origin in the navigation coordinate system; the coordinate relationship construction module is used to establish a theoretical relationship between the transponder coordinates and the iUSBL coordinate system origin coordinates; the differential equation construction module is used to establish a differential equation based on the theoretical relationship; the installation error parameter calculation module is used to establish an objective function based on the differential equation and use a nonlinear least squares solution to calculate the iUSBL installation error parameters.

[0063] The iUSBL installation error calibration system that does not rely on a fixed transponder provided in the embodiment of the present invention is for realizing the above method. Its specific functions can be referred to the above method embodiment and will not be described in detail here.

[0064] Figure 4 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 4As shown, the electronic device may include: a processor 401, a communication interface 402, a memory 403 and a communication bus 404, wherein the processor 401, the communication interface 402 and the memory 403 complete mutual communication through the communication bus 404. The processor 401 may call the logic instructions in the memory 403 to execute the iUSBL installation error calibration method, which includes: step 1: calculating the coordinates of the transponder in the iUSBL coordinate system according to the iUSBL direction finding and ranging information; step 2: using the iUSBL ranging information to assist the UUV position and attitude information provided by the INS integrated navigation, as well as the lever arm, to calculate the coordinates of the origin of the iUSBL coordinate system in the navigation coordinate system; step 3: establishing a theoretical relationship between the coordinates of the transponder and the coordinates of the origin of the iUSBL coordinate system; step 4: establishing a differential equation according to the theoretical relationship; step 5: establishing an objective function based on the differential equation and using a nonlinear least squares solution to calculate the iUSBL installation error parameters.

[0065] In addition, when the logic instructions in the above-mentioned memory 403 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0066] An embodiment of the present invention also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the methods provided by the above-mentioned method embodiments, for example, including: Step 1: Calculate the coordinates of the transponder in the iUSBL coordinate system based on the iUSBL direction finding and ranging information; Step 2: Use the iUSBL ranging information to assist the UUV position and attitude information provided by the INS integrated navigation, and the lever arm to calculate the coordinates of the origin of the iUSBL coordinate system in the navigation coordinate system; Step 3: Establish a theoretical relationship between the coordinates of the transponder and the coordinates of the origin of the iUSBL coordinate system; Step 4: Establish a differential equation based on the theoretical relationship; Step 5: Based on the differential equation, establish an objective function and use a nonlinear least squares solution to calculate the iUSBL installation error parameters.

[0067] An embodiment of the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the methods provided by the above-mentioned method embodiments are implemented, for example, including: Step 1: Calculate the coordinates of the transponder in the iUSBL coordinate system based on the iUSBL direction finding and ranging information; Step 2: Calculate the coordinates of the origin of the iUSBL coordinate system in the navigation coordinate system using the UUV position and attitude information provided by the INS integrated navigation assisted by the iUSBL ranging information, as well as the lever arm; Step 3: Establish a theoretical relationship between the coordinates of the transponder and the coordinates of the origin of the iUSBL coordinate system; Step 4: Establish a differential equation based on the theoretical relationship; Step 5: Establish an objective function based on the differential equation and use a nonlinear least squares solution to calculate the iUSBL installation error parameters.

[0068] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An iUSBL installation error calibration method that does not rely on a fixed transponder, characterized in that: include: Step 1: Calculate the coordinates of the transponder in the iUSBL coordinate system based on the iUSBL direction finding and ranging information; Step 2: Use the iUSBL ranging information to assist the UUV position and attitude information provided by the INS integrated navigation, as well as the lever arm, to calculate the origin coordinates of the iUSBL coordinate system in the navigation coordinate system; Step 3: Establish a theoretical relationship between the transponder coordinates and the origin coordinates of the iUSBL coordinate system; Step 4: Establish a differential equation based on the theoretical relationship; Step 5: Based on the differential equation, establish the objective function and use the nonlinear least squares solution method to calculate the iUSBL installation error parameters.

2. The iUSBL installation error calibration method according to claim 1, which is independent of a fixed transponder, is characterized in that: Step 1 specifically includes: in, represents the coordinates of the transponder center T in the iUSBL coordinate system a, R is the underwater acoustic ranging value, d is the array element spacing, λ is the acoustic wavelength, φ and are the phase differences of the received signals of adjacent array elements on the x-axis and y-axis respectively.

3. The iUSBL installation error calibration method according to claim 1, which is independent of a fixed transponder, is characterized in that: In step 2, the coordinates of the origin of the iUSBL coordinate system in the navigation coordinate system are: in, and They represent the position and attitude of the UUV in the navigation coordinate system n; △X i is the lever arm, which represents the position vector of the origin of the iUSBL coordinate system in the IMU coordinate system.

4. The iUSBL installation error calibration method according to claim 1, which is independent of a fixed transponder, is characterized in that: In step 3, the theoretical relationship is: Where R represents the rotation matrix, its subscript represents the coordinate system to be transformed, and its superscript represents the target coordinate system; the superscripts n, i, and a represent the navigation coordinate system, the IMU coordinate system, and the iUSBL coordinate system, respectively; the subscripts T and A represent the center of the transponder and the origin of the iUSBL coordinate system, respectively; represents the coordinates of the transponder center T in the iUSBL coordinate system a, represents the known coordinates of the transponder center T in the navigation coordinate system n, Represents the origin coordinates of the iUSBL coordinate system in the navigation coordinate system n.

5. The iUSBL installation error calibration method according to claim 4, which is independent of a fixed transponder, is characterized in that: In step 4, the difference equation is: Wherein, subscript j=1,2,3,…,J represents the observation time.

6. The iUSBL installation error calibration method according to claim 5, which is independent of a fixed transponder, is characterized in that: In step 5, the objective function is:

7. An iUSBL installation error calibration system that does not rely on a fixed transponder, characterized in that: include: A transponder coordinate calculation module, used to calculate the coordinates of the transponder in the iUSBL coordinate system according to the iUSBL direction-finding and distance-finding information; The iUSBL coordinate system origin coordinate calculation module is used to use the iUSBL ranging information to assist the UUV position and attitude information provided by the INS integrated navigation, as well as the lever arm, to calculate the iUSBL coordinate system origin coordinates in the navigation coordinate system; A coordinate relationship building module is used to establish a theoretical relationship between the transponder coordinates and the origin coordinates of the iUSBL coordinate system; A difference equation building module, used for building a difference equation according to the theoretical relationship; The installation error parameter calculation module is used to establish an objective function based on the differential equation and calculate the iUSBL installation error parameters using a nonlinear least squares solution.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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