Inertial navigation method and system based on dual modes and medium

Abstract

The invention belongs to the technical field of navigation, and discloses an inertial navigation method and system based on dual modes and a medium, the dual modes comprise a first navigation mode and a second navigation mode, the first navigation mode adopts a first combined navigation mode formed by combining an inertial unit with an ultra-short baseline acoustic positioning unit and a Doppler velocity measurement unit, and the second navigation mode adopts a second combined navigation mode formed by combining an ultra-short baseline acoustic positioning unit and a Doppler velocity measurement unit. The navigation mode II adopts a second combined navigation mode of combining an inertial unit and a geomagnetic measurement unit. The method comprises the following steps: acquiring the depth of the submersible at the current position; and updating the current position of the submersible in real time by adopting the navigation mode I and / or the navigation mode II according to the depth of the submersible at the current position. The method has high positioning accuracy.

Description

Technical Field

[0001] The present invention belongs to the field of navigation technology, and in particular relates to an inertial navigation method, system and medium based on dual mode. Background Art

[0002] Marine resource exploration refers to the exploration of oil, natural gas, renewable resources (such as wind and solar energy), and marine biological resources. The importance of marine resource exploration lies in its foundation for the development and utilization of marine resources.

[0003] During the exploration process, the location and navigation of the submersible are particularly important. Currently, conventional navigation methods include the Global Positioning System and inertial navigation. In order to improve the accuracy of positioning, the Global Positioning System and inertial navigation are usually used in combination, and the Global Positioning System is used to correct the errors of the inertial navigation system.

[0004] However, underwater satellite signals attenuate significantly and are lost at depths exceeding a certain threshold. Therefore, the Global Positioning System (GPS) cannot provide accurate positioning services underwater. Currently, other underwater positioning methods, such as acoustics and magnetic fields, offer limited accuracy and are incapable of providing accurate positioning services underwater. Summary of the Invention

[0005] The purpose of the present invention is to provide an inertial navigation method, system and medium based on dual mode to solve the problem that a single positioning method has low positioning accuracy and cannot provide accurate positioning services underwater.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides an inertial navigation method based on a dual mode, wherein the dual mode includes a navigation mode 1 and a navigation mode 2, wherein the navigation mode 1 adopts a first combined navigation mode in which an inertial unit is combined with an ultra-short baseline acoustic positioning unit and a Doppler velocity measurement unit, and the navigation mode 2 adopts a second combined navigation mode in which an inertial unit is combined with a geomagnetic measurement unit, and the method includes: Get the depth of the submersible at its current location; Determining whether the depth of the current position is less than a first preset depth, and if so, updating the current position of the submersible in real time based on the first combined navigation mode; If not, determining whether the depth of the current position is greater than a second preset depth, and if so, updating the current position of the submersible in real time based on the second combined navigation mode, wherein the second preset depth is greater than the first preset depth; If not, based on the first combined navigation mode, the current position of the submersible is updated in real time to obtain a first position; based on the second combined navigation mode, the current position of the submersible is updated in real time to obtain a second position; A fusion coefficient of the first position and the second position is constructed based on the depth of the current position, and the first position and the second position are fused based on the fusion coefficient to obtain a fused position, and the current position of the submersible is updated with the fused position.

[0007] Preferably, constructing a fusion coefficient of the first position and the second position based on the depth of the current position, and fusing the first position and the second position based on the fusion coefficient to obtain a fused position includes: Calculating a first depth difference between the depth of the current position and the second preset depth and a second depth difference between the first preset depth and the second preset depth; Constructing initial coefficients for fusing the first position and the second position; The initial coefficient is updated based on the ratio of the first depth difference to the second depth difference to obtain a fusion coefficient; The first position and the second position are fused based on the fusion coefficient to obtain a fused position.

[0008] Preferably, the function expression of the fusion position is: ; Where, is the fusion position, For the first position, For the second position, is the initial coefficient, The value range of is [0.7,0.9], is the first depth difference, is the second depth difference, is the fusion coefficient.

[0009] Preferably, the method further comprises: Get the real-time speed of the submersible; The first preset depth is dynamically adjusted based on the real-time speed.

[0010] Preferably, based on the first combined navigation mode, updating the current position of the submersible in real time includes: Obtain the inertial velocity, inertial position, and attitude information output by the inertial unit, the beam configuration and installation angle error of the Doppler velocity measurement unit, and the measured values of the transponder position and attitude of the ultra-short baseline acoustic positioning unit; Based on the beam configuration, inertial velocity and installation angle error, the frequency shift measurement equation of the Doppler velocity measurement unit is constructed; Based on the inertial position, attitude information, transponder position and attitude measured values, the relative position measurement equation of the ultra-short baseline acoustic positioning unit is constructed; The relative position measurement equation and the frequency shift measurement equation are used as the first measurement equation of the Kalman filter, and the first state equation of the Kalman filter is constructed based on the error term of the inertial unit; updating the error term based on the first measurement equation and the first state equation of the Kalman filter to obtain an updated error term; The inertial position is corrected based on the updated error term to obtain a corrected inertial position, and the corrected inertial position is used as the updated current position of the submersible.

[0011] Preferably, based on the beam configuration, inertial velocity and installation angle error, a frequency shift measurement equation of the Doppler velocity measurement unit is constructed, including: The inertial velocity of the inertial unit is converted into the coordinate system of the Doppler velocity measurement unit to obtain the converted velocity; Obtaining the installation angle error of the Doppler velocity measurement unit, and calculating the frequency shift estimate of the beam based on the installation angle error and the converted velocity; A frequency shift measurement equation is constructed based on the actual frequency shift value and the estimated frequency shift value.

[0012] Preferably, based on the inertial position, attitude information, transponder position and attitude measured values, a relative position measurement equation of the ultra-short baseline acoustic positioning unit is constructed, including: Calculating the relative position of the transponder in the coordinate system of the inertial unit based on the transponder position and the inertial position; Calculate the attitude estimate of the ultra-short baseline acoustic positioning unit based on the relative position and attitude information of the transponder in the coordinate system of the inertial unit; According to the attitude estimation value and the attitude measurement value, the relative position measurement equation is constructed.

[0013] Preferably, based on the second combined navigation mode, updating the current position of the submersible in real time includes: Obtaining the inertial position output by the inertial unit and the geomagnetic signal output by the geomagnetic measurement unit; Constructing a geomagnetic position equation based on the geomagnetic signal output by the geomagnetic measurement unit; The second state equation of the Kalman filter is constructed based on the error term of the inertial unit, and the second measurement equation of the Kalman filter is constructed based on the geomagnetic position equation; The error term is updated based on the second state equation and the second measurement equation of the Kalman filter to obtain an updated error term; The inertial position is corrected based on the updated error term to obtain a corrected inertial position, and the corrected inertial position is used as the updated current position of the submersible.

[0014] In a second aspect, the present invention provides a dual-mode inertial navigation system for implementing the above-mentioned dual-mode inertial navigation method, the system comprising: The depth acquisition module is used to obtain the depth of the submersible at its current location; A first updating module is configured to determine whether the depth of the current position is less than a first preset depth, and if so, update the current position of the submersible in real time based on the first combined navigation mode; a second updating module, configured to, if not, determine whether the depth of the current position is greater than a second preset depth; and if so, update the current position of the submersible in real time based on a second combined navigation mode, wherein the second preset depth is greater than the first preset depth; A third updating module is configured to, if not, update the current position of the submersible in real time based on the first combined navigation mode to obtain a first position; and update the current position of the submersible in real time based on the second combined navigation mode to obtain a second position; The position fusion module is used to construct a fusion coefficient of the first position and the second position based on the depth of the current position, fuse the first position and the second position based on the fusion coefficient to obtain a fused position, and update the current position of the submersible with the fused position.

[0015] 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 above-mentioned dual-mode-based inertial navigation method when executing the computer program.

[0016] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the above-mentioned dual-mode-based inertial navigation method when executed by a processor.

[0017] Beneficial effects: The present invention adopts a first combined navigation mode of an inertial unit, an ultra-short baseline acoustic positioning unit and a Doppler velocity measurement unit as navigation mode one, and adopts a second combined navigation mode of an inertial unit and a geomagnetic measurement unit as navigation mode two. When the depth of the submersible is less than the first preset depth, navigation mode one is adopted to provide positioning services, giving full play to the positioning accuracy of the ultra-short baseline acoustic positioning unit; when the depth of the submersible is greater than the second preset depth, navigation mode two is adopted to provide positioning services. Since the geomagnetic field in the deep sea is relatively stable, it can be used to correct the positioning error of the inertial unit and improve the positioning accuracy. degree; and when the depth of the submersible is between the first preset depth and the second preset depth, based on the first combined navigation mode, the current position of the submersible is updated in real time to obtain the first position; based on the second combined navigation mode, the current position of the submersible is updated in real time to obtain the second position; then, based on the depth of the current position, a fusion coefficient of the first position and the second position is constructed, and the first position and the second position are fused based on the fusion coefficient to obtain the fused position, and the current position of the submersible is updated with the fused position; the two modes provide positioning services at the same time to avoid excessive positioning errors caused by data mutations when the two modes are switched. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings: Figure 1 is a flow chart of a dual-mode inertial navigation method provided by one embodiment of the present invention; Figure 2 It is a block diagram of a dual-mode inertial navigation system provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be briefly introduced below in conjunction with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0020] Example 1 Figure 1 FIG. 1 is a flow chart of a dual-mode inertial navigation method provided by an embodiment of the present invention. Figure 1As shown, this embodiment provides the dual mode including navigation mode 1 and navigation mode 2, wherein the navigation mode 1 adopts a first combined navigation mode combining an inertial unit with an ultra-short baseline acoustic positioning unit and a Doppler velocity measurement unit, and the navigation mode 2 adopts a second combined navigation mode combining an inertial unit with a geomagnetic measurement unit.

[0021] The inertial unit primarily consists of gyroscopes and accelerometers, which are installed on the submersible. The accelerometer measures the submersible's acceleration, while the gyroscope measures its angular velocity. These devices work together to provide basic motion information for the submersible.

[0022] Among them, the ultra-short baseline acoustic positioning unit mainly includes: acoustic array, transponder and deck processing system; An acoustic array consists of a transmitting transducer and a receiving array, typically integrated into the same device. The transmitting transducer sends acoustic signals underwater, while the receiving array captures the return signals through multiple sensors, measuring phase and time differences to calculate the target's direction and range. For example, the array on a mother ship interacts with the transponder of an underwater target through acoustic waves, acting like an "ear" that receives signals with different time delays to locate the target. The transponder is fixed on the submersible, receives the acoustic signal from the array and returns a response pulse, forming a complete positioning signal chain; The deck processing system includes a data solution unit and a communication module, which is responsible for converting the raw data of the acoustic array into coordinate information.

[0023] Among them, the Doppler speed measurement unit mainly includes a Doppler speed meter, which measures the speed of the submersible through the Doppler effect.

[0024] Among them, the geomagnetic measurement unit mainly includes a magnetometer, which is used to measure the magnetic field data of the submersible's location.

[0025] Therefore, the inertial navigation method of this embodiment includes: Step S10: Obtain the depth of the submersible at its current position; in this embodiment, when the submersible is on the surface, the initial position of the submersible can be determined by the global positioning system, and the depth can be determined by the ultra-short baseline acoustic positioning unit; when the submersible dives, the depth of the current position can be calculated based on the depth of the position at the previous moment.

[0026] Step S20: determining whether the depth of the current position is less than a first preset depth; if so, updating the current position of the submersible in real time based on the first combined navigation mode.

[0027] In this embodiment, when the submersible is at a depth less than the first preset depth, navigation mode 1 is used to provide positioning services, fully utilizing the positioning accuracy of the ultra-short baseline acoustic positioning unit. Specifically, based on the first combined navigation mode, the submersible's current position is updated in real time, including: Step S201: Obtain the inertial velocity, inertial position and attitude information output by the inertial unit, the beam configuration and installation angle error of the Doppler velocity measurement unit, and the measured values of the transponder position and attitude of the ultra-short baseline acoustic positioning unit; wherein the beam configuration is to configure the type of beam, for example, single beam: only one transducer, sound waves are transmitted and received in a single direction; dual beam: two transducers, sound waves are transmitted and received in two perpendicular directions, and horizontal and vertical velocity components can be measured; triple beam: three transducers, sound waves are transmitted and received in three mutually perpendicular directions, and velocity components in three directions can be measured; quad beam: four transducers, usually in a cross or X-type configuration, can measure velocity components in three directions and provide more accurate velocity measurement results.

[0028] Step S202: constructing a frequency shift measurement equation of the Doppler velocity measurement unit based on the beam configuration, inertial velocity and installation angle error.

[0029] In this embodiment, the specific steps of constructing the frequency shift measurement equation of the Doppler velocity measurement unit based on the beam configuration, inertial velocity, and installation angle error include: Step a10: converting the inertial velocity of the inertial unit into the coordinate system of the Doppler velocity measurement unit to obtain the converted velocity; Step a20: Obtaining the installation angle error of the Doppler velocity measurement unit, and calculating the frequency shift estimate of the beam based on the installation angle error and the converted velocity; Step a30: Construct a frequency shift measurement equation based on the actual frequency shift value and the estimated frequency shift value.

[0030] Step S203: Based on the inertial position, attitude information, transponder position and attitude measured values, a relative position measurement equation of the ultra-short baseline acoustic positioning unit is constructed.

[0031] In this embodiment, the specific steps of constructing the relative position measurement equation of the ultra-short baseline acoustic positioning unit based on the inertial position, attitude information, transponder position and attitude measured value include: Step b10: Calculating the relative position of the transponder in the coordinate system of the inertial unit based on the transponder position and the inertial position; Step b20: Calculating an estimated attitude value of the ultra-short baseline acoustic positioning unit based on the relative position and attitude information of the transponder in the coordinate system of the inertial unit; Step b30: Construct a relative position measurement equation based on the attitude estimation value and the attitude measurement value.

[0032] Step S204: Use the relative position measurement equation and the frequency shift measurement equation as the first measurement equation of the Kalman filter, and construct the first state equation of the Kalman filter based on the error terms of the inertial unit; wherein the error terms mainly include: velocity error, attitude error, position error, accelerometer zero bias and gyroscope zero, etc.

[0033] Step S205: Update the error terms based on the first measurement equation and the first state equation of the Kalman filter to obtain updated error terms. The updated error terms mainly include: updated velocity error, updated attitude error, updated position error, updated accelerometer zero bias and updated gyroscope zero, etc.

[0034] Step S206: Correct the inertial position based on the updated error term to obtain the corrected inertial position, and use the corrected inertial position as the updated current position of the submersible. That is, use the updated error term as the feedback correction value of the inertial unit, and correct the inertial speed, inertial position and attitude information through the feedback correction value to obtain a more accurate current position of the submersible.

[0035] In this embodiment, the inertial unit is corrected simultaneously by the Doppler velocity measurement unit and the ultra-short baseline acoustic positioning unit, so that the positioning of the navigation mode one is more accurate, has higher fault tolerance and stability.

[0036] Step S30: If not, determine whether the depth of the current position is greater than a second preset depth. If so, update the current position of the submersible in real time based on the second combined navigation mode, wherein the second preset depth is greater than the first preset depth.

[0037] In this embodiment, the second preset depth is 200m~500m, which can be flexibly selected according to the sea area in which the submersible is located; as the depth of the submersible increases, the positioning error of the ultra-short baseline acoustic positioning unit increases, and it is impossible to provide accurate error correction services for the inertial unit in the deep sea. Therefore, in the deep sea, the submersible is only positioned by the second combined navigation mode. Since the geomagnetic field in the deep sea is relatively stable, it can be used to correct the positioning error of the inertial unit and improve the positioning accuracy.

[0038] In this embodiment, based on the second combined navigation mode, the current position of the submersible is updated in real time, including: Step S301: Acquire the inertial position output by the inertial unit and the geomagnetic signal output by the geomagnetic measurement unit.

[0039] Step S302: constructing a geomagnetic position equation based on the geomagnetic signal output by the geomagnetic measurement unit.

[0040] In this embodiment, a magnetometer is used to measure the total magnetic field strength of the submersible at the current position, and the measured value is recorded; the magnetic field gradient tensor at the current position is calculated through a cross-shaped magnetic measurement array or other magnetic measurement array configuration, and a linear fit is performed between the magnetic field gradient tensor and the position of the submersible to obtain a linear equation of the magnetic field-position, which is then discretized to obtain the geomagnetic position equation.

[0041] Step S303: Construct the second state equation of the Kalman filter based on the error terms of the inertial unit, and construct the second measurement equation of the Kalman filter based on the geomagnetic position equation; similarly, the error terms of the inertial unit mainly include: velocity error, attitude error, position error, accelerometer zero bias and gyroscope zero, etc.

[0042] Step S304: updating the error term based on the second state equation and the second measurement equation of the Kalman filter to obtain an updated error term.

[0043] Step S305: Correcting the inertial position based on the updated error term to obtain a corrected inertial position, and using the corrected inertial position as the updated current position of the submersible.

[0044] Step S40: If not, based on the first combined navigation mode, the current position of the submersible is updated in real time to obtain a first position; based on the second combined navigation mode, the current position of the submersible is updated in real time to obtain a second position.

[0045] Step S50: constructing a fusion coefficient of the first position and the second position based on the depth of the current position, fusing the first position and the second position based on the fusion coefficient to obtain a fused position, and updating the current position of the submersible with the fused position.

[0046] In this embodiment, since different navigation modes are used at different depths, there will be a switching process from navigation mode one to navigation mode two in continuous detection tasks. Since the Kalman filter processes different data in the two modes, there will be data mutations in the switching process, which makes it impossible to correct the inertial unit normally, and the positioning error is too large. In order to solve this problem, in this embodiment, when the depth of the submersible is between the first preset depth and the second preset depth, two navigation modes are used at the same time, and a position is calculated using each of the two navigation modes, namely the first position and the second position, and then the two positions are fused to obtain the final fused position, and the fused position is used as the latest current position.

[0047] Specifically, constructing a fusion coefficient of the first position and the second position based on the depth of the current position, fusing the first position and the second position based on the fusion coefficient to obtain a fusion position, including: Step S501: calculating a first depth difference between the depth of the current position and a second preset depth and a second depth difference between the first preset depth and the second preset depth.

[0048] Step S502: constructing initial coefficients for fusing the first position and the second position.

[0049] Step S503: updating the initial coefficient based on the ratio of the first depth difference to the second depth difference to obtain a fusion coefficient.

[0050] Step S504: Fusing the first position and the second position based on the fusion coefficient to obtain a fused position.

[0051] In this embodiment, the function expression of the fusion position is: ; Where, is the fusion position, For the first position, For the second position, is the initial coefficient, The value range of is [0.7,0.9], is the first depth difference, is the second depth difference, is the fusion coefficient.

[0052] In this embodiment, when the submersible is between the first preset depth and the second preset depth, as the submersible dives, the proportion of the first position in the fused position gradually decreases. When the depth of the submersible is equal to the second preset depth, the fused position is the second position, and only navigation mode two is used to update the current position of the submersible.

[0053] As a further optimization of this embodiment, due to the different detection speeds of the submersible, it is necessary to reasonably configure the range of the first preset depth. Therefore, the method further includes: Step c10: Obtain the real-time speed of the submersible; Step c20: Dynamically adjust the first preset depth based on the real-time speed, wherein the dynamic adjustment method is: the real-time speed is negatively correlated with the size of the first preset depth. When the real-time speed is greater, the value of the first preset depth is smaller and the second depth difference is larger, ensuring that the coexistence time of the two navigation modes is sufficient to avoid data mutations.

[0054] The present invention adopts a first combined navigation mode of an inertial unit, an ultra-short baseline acoustic positioning unit and a Doppler velocity measurement unit as navigation mode one, and adopts a second combined navigation mode of an inertial unit and a geomagnetic measurement unit as navigation mode two. When the depth of the submersible is less than the first preset depth, navigation mode one is adopted to provide positioning services, giving full play to the positioning accuracy of the ultra-short baseline acoustic positioning unit; when the depth of the submersible is greater than the second preset depth, navigation mode two is adopted to provide positioning services. Since the geomagnetic field in the deep sea is relatively stable, it can be used to correct the positioning error of the inertial unit and improve the positioning accuracy. degree; and when the depth of the submersible is between the first preset depth and the second preset depth, based on the first combined navigation mode, the current position of the submersible is updated in real time to obtain the first position; based on the second combined navigation mode, the current position of the submersible is updated in real time to obtain the second position; then, based on the depth of the current position, a fusion coefficient of the first position and the second position is constructed, and the first position and the second position are fused based on the fusion coefficient to obtain the fused position, and the current position of the submersible is updated with the fused position; the two modes provide positioning services at the same time to avoid excessive positioning errors caused by data mutations when the two modes are switched.

[0055] Example 2 Figure 2 FIG is a block diagram of a dual-mode inertial navigation system provided by an embodiment of the present invention. Figure 2 As shown, this embodiment provides a dual-mode inertial navigation system for implementing the dual-mode inertial navigation method in Example 1. The system includes: The depth acquisition module is used to obtain the depth of the submersible at its current location; A first updating module is configured to determine whether the depth of the current position is less than a first preset depth, and if so, update the current position of the submersible in real time based on the first combined navigation mode; a second updating module, configured to, if not, determine whether the depth of the current position is greater than a second preset depth; and if so, update the current position of the submersible in real time based on a second combined navigation mode, wherein the second preset depth is greater than the first preset depth; A third updating module is configured to, if not, update the current position of the submersible in real time based on the first combined navigation mode to obtain a first position; and update the current position of the submersible in real time based on the second combined navigation mode to obtain a second position; The position fusion module is used to construct a fusion coefficient of the first position and the second position based on the depth of the current position, fuse the first position and the second position based on the fusion coefficient to obtain a fused position, and update the current position of the submersible with the fused position.

[0056] This embodiment also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the dual-mode-based inertial navigation method in the first embodiment is implemented.

[0057] This embodiment further provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the dual-mode-based inertial navigation method in the first embodiment is implemented.

[0058] The present invention adopts a first combined navigation mode of an inertial unit, an ultra-short baseline acoustic positioning unit and a Doppler velocity measurement unit as navigation mode one, and adopts a second combined navigation mode of an inertial unit and a geomagnetic measurement unit as navigation mode two. When the depth of the submersible is less than the first preset depth, navigation mode one is adopted to provide positioning services, giving full play to the positioning accuracy of the ultra-short baseline acoustic positioning unit; when the depth of the submersible is greater than the second preset depth, navigation mode two is adopted to provide positioning services. Since the geomagnetic field in the deep sea is relatively stable, it can be used to correct the positioning error of the inertial unit and improve the positioning accuracy. degree; and when the depth of the submersible is between the first preset depth and the second preset depth, based on the first combined navigation mode, the current position of the submersible is updated in real time to obtain the first position; based on the second combined navigation mode, the current position of the submersible is updated in real time to obtain the second position; then, based on the depth of the current position, a fusion coefficient of the first position and the second position is constructed, and the first position and the second position are fused based on the fusion coefficient to obtain the fused position, and the current position of the submersible is updated with the fused position; the two modes provide positioning services at the same time to avoid excessive positioning errors caused by data mutations when the two modes are switched.

[0059] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0060] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A system that specifies the functions of a box or boxes.

[0061] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A dual-mode inertial navigation method, characterized in that: The dual mode includes navigation mode 1 and navigation mode 2, wherein the navigation mode 1 adopts a first combined navigation mode combining an inertial unit with an ultra-short baseline acoustic positioning unit and a Doppler velocity measurement unit, and the navigation mode 2 adopts a second combined navigation mode combining an inertial unit with a geomagnetic measurement unit. The method includes: Get the depth of the submersible at its current location; Determining whether the depth of the current position is less than a first preset depth, and if so, updating the current position of the submersible in real time based on the first combined navigation mode; If not, determining whether the depth of the current position is greater than a second preset depth, and if so, updating the current position of the submersible in real time based on the second combined navigation mode, wherein the second preset depth is greater than the first preset depth; If not, based on the first combined navigation mode, the current position of the submersible is updated in real time to obtain a first position; based on the second combined navigation mode, the current position of the submersible is updated in real time to obtain a second position; A fusion coefficient of the first position and the second position is constructed based on the depth of the current position, and the first position and the second position are fused based on the fusion coefficient to obtain a fused position, and the current position of the submersible is updated with the fused position.

2. The dual-mode inertial navigation method according to claim 1, characterized in that: Constructing a fusion coefficient of the first position and the second position based on the depth of the current position, and fusing the first position and the second position based on the fusion coefficient to obtain a fused position, including: Calculating a first depth difference between the depth of the current position and the second preset depth and a second depth difference between the first preset depth and the second preset depth; Constructing initial coefficients for fusing the first position and the second position; The initial coefficient is updated based on the ratio of the first depth difference to the second depth difference to obtain a fusion coefficient; The first position and the second position are fused based on the fusion coefficient to obtain a fused position.

3. The dual-mode inertial navigation method according to claim 2, characterized in that: The function expression of the fusion position is: ； Where, is the fusion position, For the first position, For the second position, is the initial coefficient, The value range of is [0.7,0.9], is the first depth difference, is the second depth difference, is the fusion coefficient.

4. The dual-mode inertial navigation method according to claim 2 or 3, characterized in that: The method further comprises: Get the real-time speed of the submersible; The first preset depth is dynamically adjusted based on the real-time speed.

5. The dual-mode inertial navigation method according to claim 1, characterized in that: Based on the first combined navigation mode, the current position of the submersible is updated in real time, including: Obtain the inertial velocity, inertial position, and attitude information output by the inertial unit, the beam configuration and installation angle error of the Doppler velocity measurement unit, and the measured values of the transponder position and attitude of the ultra-short baseline acoustic positioning unit; Based on the beam configuration, inertial velocity and installation angle error, the frequency shift measurement equation of the Doppler velocity measurement unit is constructed; Based on the inertial position, attitude information, transponder position and attitude measured values, the relative position measurement equation of the ultra-short baseline acoustic positioning unit is constructed; The relative position measurement equation and the frequency shift measurement equation are used as the first measurement equation of the Kalman filter, and the first state equation of the Kalman filter is constructed based on the error term of the inertial unit; updating the error term based on the first measurement equation and the first state equation of the Kalman filter to obtain an updated error term; The inertial position is corrected based on the updated error term to obtain a corrected inertial position, and the corrected inertial position is used as the updated current position of the submersible.

6. The dual-mode inertial navigation method according to claim 5, characterized in that: Based on the beam configuration, inertial velocity, and installation angle error, the frequency shift measurement equation of the Doppler velocity measurement unit is constructed, including: The inertial velocity of the inertial unit is converted into the coordinate system of the Doppler velocity measurement unit to obtain the converted velocity; Obtaining the installation angle error of the Doppler velocity measurement unit, and calculating the frequency shift estimate of the beam based on the installation angle error and the converted velocity; A frequency shift measurement equation is constructed based on the actual frequency shift value and the estimated frequency shift value.

7. The dual-mode inertial navigation method according to claim 5, characterized in that: Based on the inertial position, attitude information, transponder position and attitude measured values, the relative position measurement equation of the ultra-short baseline acoustic positioning unit is constructed, including: Calculating the relative position of the transponder in the coordinate system of the inertial unit based on the transponder position and the inertial position; Calculate the attitude estimate of the ultra-short baseline acoustic positioning unit based on the relative position and attitude information of the transponder in the coordinate system of the inertial unit; According to the attitude estimation value and the attitude measurement value, the relative position measurement equation is constructed.

8. The dual-mode inertial navigation method according to claim 1, characterized in that: Based on the second combined navigation mode, the current position of the submersible is updated in real time, including: Obtaining the inertial position output by the inertial unit and the geomagnetic signal output by the geomagnetic measurement unit; Constructing a geomagnetic position equation based on the geomagnetic signal output by the geomagnetic measurement unit; The second state equation of the Kalman filter is constructed based on the error term of the inertial unit, and the second measurement equation of the Kalman filter is constructed based on the geomagnetic position equation; The error term is updated based on the second state equation and the second measurement equation of the Kalman filter to obtain an updated error term; The inertial position is corrected based on the updated error term to obtain a corrected inertial position, and the corrected inertial position is used as the updated current position of the submersible.

9. A dual-mode inertial navigation system for implementing the dual-mode inertial navigation method according to any one of claims 1 to 8, characterized in that: The system comprises: The depth acquisition module is used to obtain the depth of the submersible at its current location; A first updating module is configured to determine whether the depth of the current position is less than a first preset depth, and if so, update the current position of the submersible in real time based on the first combined navigation mode; a second updating module, configured to, if not, determine whether the depth of the current position is greater than a second preset depth; and if so, update the current position of the submersible in real time based on a second combined navigation mode, wherein the second preset depth is greater than the first preset depth; A third updating module is configured to, if not, update the current position of the submersible in real time based on the first combined navigation mode to obtain a first position; and update the current position of the submersible in real time based on the second combined navigation mode to obtain a second position; The position fusion module is used to construct a fusion coefficient of the first position and the second position based on the depth of the current position, fuse the first position and the second position based on the fusion coefficient to obtain a fused position, and update the current position of the submersible with the fused position.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the dual-mode-based inertial navigation method according to any one of claims 1 to 8 is implemented.

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