Underwater platform inertial navigation calibration method and device

Abstract

The present invention belongs to the field of navigation and positioning technology. To address the problem of large calibration errors in the inertial navigation systems of existing underwater carrier platforms, the present invention provides an underwater platform inertial navigation calibration method and device. The method includes releasing multiple buoys. After the buoys emerge from the water, they receive satellite positioning signals for positioning. The underwater platform continuously transmits interrogation signals through bow and stern hydroacoustic transducers. After receiving the interrogation signals, the buoys transmit satellite positioning information and response signals back to the underwater platform. The coordinates of the bow and stern hydroacoustic transducers are calculated based on the satellite positioning information and the hydroacoustic positioning information. Based on the coordinates of the bow and stern hydroacoustic transducers, the real-time coordinates and heading of the inertial navigation system are obtained to calibrate the inertial navigation system. On the one hand, the present invention makes the underwater carrier platform highly concealed and has a flexible operating range, breaking the restrictions of the operating area. On the other hand, it solves the problem of large errors in underwater GNSS technology and improves the accuracy of inertial navigation calibration.

Description

Technical Field

[0001] The present invention belongs to the field of navigation and positioning technology, and in particular relates to an underwater platform inertial navigation calibration method and device. Background Art

[0002] GPS (Global Positioning System) positioning technology is widely used for high-precision navigation and positioning of various moving vehicles at sea, on land, and in the air. Because electromagnetic signals cannot propagate in water, submarines, underwater robots, and other underwater vehicles primarily rely on inertial navigation systems for underwater navigation and positioning. The inertial navigation systems used by large underwater vehicles generally offer high autonomous navigation accuracy, but the positional errors of these systems accumulate over time. When these errors reach a certain level, the underwater vehicle must regularly surface to obtain position information and recalibrate the inertial navigation system. Extending the recalibration period and underwater endurance of underwater vehicles is key to improving their stealth capabilities.

[0003] Underwater GPS technology extends GPS surface positioning underwater by using techniques such as underwater acoustic positioning to determine the relative position of underwater targets and surface GPS antennas. Ultra-Short Base Line (USBL) underwater acoustic positioning uses an acoustic array consisting of a single, compact transducer. This system offers simplicity, ease of installation and operation, and high ranging accuracy. The transducer can be integrated with the inertial navigation system, making the device plug-and-play and eliminating the need for fixed installation. Furthermore, the use of a multi-element array can improve long-range positioning accuracy.

[0004] Traditional underwater GPS technology generally uses a single buoy and a single set of USBL for calibration, which has limited positioning accuracy; or it is carried out in sea areas where transponders have been deployed on the seabed in advance, which has a limited operating range. Summary of the Invention

[0005] The embodiments of the present application provide an underwater platform inertial navigation calibration method and device, which, on the one hand, can solve the problems that long-endurance underwater carrier platforms need to surface, have poor concealment, and need to operate in an environment where they are deployed in advance; on the other hand, it solves the problem of large errors in underwater GNSS technology and improves the accuracy of inertial navigation calibration.

[0006] In a first aspect, an embodiment of the present application provides an underwater platform inertial navigation calibration method, comprising:

[0007] Release multiple buoys, and after the buoys emerge from the water, they receive satellite positioning signals for positioning;

[0008] The underwater platform continuously sends interrogation signals through the bow and stern hydroacoustic transducers; after receiving the interrogation signals, the buoy sends satellite positioning information and a response signal back to the underwater platform;

[0009] The coordinates of the bow and stern hydroacoustic transducers are calculated based on the satellite positioning information and the hydroacoustic positioning information;

[0010] The real-time coordinates and heading of the inertial navigation system are obtained according to the coordinates of the bow and stern hydroacoustic transducers, and the inertial navigation system is calibrated according to the obtained real-time coordinates and heading; the relative positional relationship between the bow and stern hydroacoustic transducers and the inertial navigation system is fixed and known, and the computing module of the underwater platform converts the geometric coordinates of the bow and stern hydroacoustic transducers to obtain the real-time coordinates and heading of the inertial navigation system, and sends the obtained real-time coordinates and heading to the inertial navigation system, and the inertial navigation system is calibrated according to the received real-time coordinates and heading.

[0011] In some embodiments, multiple buoys are released, and after the buoys emerge from the water, satellite positioning signals are received for positioning, including: the underwater platform travels according to a preset route, and multiple buoys are released in sequence, and after the buoys emerge from the water, satellite positioning signals are received for positioning.

[0012] In some embodiments, the buoy includes a satellite signal positioning module, an antenna, a hydroacoustic communication module and a hydroacoustic transponder. The buoy is positioned by the satellite signal positioning module and the antenna. The hydroacoustic transponder is used to receive the inquiry signal sent by the hydroacoustic transducer. The buoy transmits the positioning information and the response signal to the underwater platform through the hydroacoustic communication module and the hydroacoustic transponder.

[0013] In some embodiments, calculating the coordinates of the bow and stern hydroacoustic transducers based on the satellite positioning information and the hydroacoustic positioning information includes:

[0014] Step 1: Assume that the coordinates of the underwater acoustic transducer at any time k are , the position of the buoy's hydroacoustic transponder is , the round trip time of the acoustic ranging signal is , the speed of sound is C, then the basic observation equation from i to j is:

[0015]

[0016] in, is the geometric distance from i to j, is the distance observation value, is the sound velocity measurement error, is the underwater acoustic transducer delay error, is the underwater acoustic transponder delay error, is the random error of acoustic ranging, i represents the underwater acoustic transducer, and j represents the buoy;

[0017] The position of the inertial navigation system on the underwater platform is converted to the position on the underwater acoustic transducer: ,but The error equation obtained by linearizing the observation equation is:

[0018]

[0019] in, , , is the coordinate correction number; if the variance of the epoch observer is , the unit weight variance is , a random model can be constructed:

[0020]

[0021] in is the incident angle between buoy j and transducer i, then the variance-covariance matrix for:

[0022]

[0023] Selecting the first buoy that meets the preset conditions as the reference buoy;

[0024] Step 2: When the underwater acoustic transducer observes the reference buoy and buoy j synchronously, the difference between the observation equations of buoy j and the reference buoy can eliminate the transducer delay error and greatly reduce the error of the sound velocity measurement system. ,Right now

[0025] The single-difference observation equation between buoys is obtained as follows:

[0026]

[0027] in, Represents the single difference symbol of the transponder difference between buoys, is the sound velocity measurement error of buoy j, is the sound velocity measurement error of the reference buoy, is the difference in observations between buoy j and the reference buoy, is the observation matrix composed of direction cosines, dX is the coordinate correction number, is the time delay error between buoy j and the reference buoy, is the random error of acoustic ranging;

[0028] Assume the single difference conversion factor between buoys:

[0029]

[0030] According to the error propagation law, the variance-covariance matrix of the single difference between buoys is for:

[0031]

[0032] Step 3: When the bow and stern hydroacoustic transducers synchronously observe the buoy j, the time delay errors of the transducer and the transponder can be eliminated at the same time, and the sound velocity measurement error can be greatly reduced. Thus, the double-difference observation equation is obtained:

[0033]

[0034] in, is the double difference symbol;

[0035] Variance-covariance matrix of single differences between buoys for:

[0036]

[0037] Step 4: The weighted least squares model is:

[0038]

[0039] Among them, L is the observation value, A is the coefficient matrix, X is the state vector, v is the observation value residual, and E(v)=0 is the least squares assumption. is the unit weighted error, P is the weight matrix of each observation equation;

[0040] The solution is obtained under the least squares criterion, and the double-difference observation equation and the stochastic model are introduced to calculate the geometric coordinates of the bow and stern hydroacoustic transducers.

[0041] In some embodiments, the buoy with the largest elevation angle or the strongest acoustic signal quality is selected as the reference buoy; or the reference buoy is determined based on the elevation angle and the acoustic signal quality.

[0042] In some embodiments, the method further includes recovering the buoy after the inertial navigation system completes calibration.

[0043] In a second aspect, the present application provides an underwater platform inertial navigation calibration device, comprising:

[0044] A plurality of buoys, each of which floats on the water surface and is used to receive satellite positioning signals for positioning;

[0045] an underwater platform, configured to continuously send interrogation signals via a bow hydroacoustic transducer and a stern hydroacoustic transducer;

[0046] The buoy is used to send satellite positioning information and a response signal back to the underwater platform after receiving the inquiry signal;

[0047] The underwater platform is used to: calculate the coordinates of the bow and stern hydroacoustic transducers based on satellite positioning information and hydroacoustic positioning information; obtain the real-time coordinates and heading of the inertial navigation system based on the coordinates of the bow and stern hydroacoustic transducers, and calibrate the inertial navigation system based on the obtained real-time coordinates and heading; the relative positional relationship between the bow and stern hydroacoustic transducers and the inertial navigation system is fixed and known, and the calculation module of the underwater platform converts the geometric coordinates of the bow and stern hydroacoustic transducers to obtain the real-time coordinates and heading of the inertial navigation system, sends the obtained real-time coordinates and heading to the inertial navigation system, and calibrates the inertial navigation system based on the received real-time coordinates and heading.

[0048] In a third aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of any of the above methods when executed by a processor.

[0049] In a fourth aspect, the present application provides an underwater carrier platform, which uses any of the above-mentioned underwater platform inertial navigation calibration methods to calibrate the inertial navigation system.

[0050] The underwater platform inertial navigation calibration method and device according to the embodiment of the present application have the following beneficial effects:

[0051] On the one hand, this application solves the problems that long-endurance underwater carrier platforms need to surface, have poor concealment, and need to operate in an environment where they are deployed in advance. It has high concealment, a free operating range, and breaks through the limitations of the operating area. On the other hand, it solves the problem of large errors in underwater GNSS technology and improves the accuracy of inertial navigation calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a flow chart of the underwater platform inertial navigation calibration method according to an embodiment of the present application;

[0053] Figure 2 This is a schematic diagram of the principle of double-difference underwater positioning and inertial navigation calibration of the vehicle based on the buoy array in this application;

[0054] Figure 3 This is a schematic diagram of the buoy structure in this application;

[0055] Figure 4 This is a flowchart of the high-precision underwater platform inertial navigation calibration method based on GNSS / hydroacoustic buoy array in this application;

[0056] Figure 5 a schematic diagram of the route adopted for the release of the buoys in this application;

[0057] Figure 6 This is a flow chart of the double-difference underwater positioning and inertial navigation calibration procedure for the underwater carrier platform navigation system. DETAILED DESCRIPTION

[0058] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0059] In the following description, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The following description provides multiple embodiments of the present invention, and different embodiments can be replaced or combined, so this application can also be considered to include all possible combinations of the same and / or different embodiments described. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then this application should also be considered to include embodiments containing one or more of all other possible combinations of features A, B, C, and D, even though such embodiments may not be explicitly described in the following text.

[0060] like Figure 1 As shown, the underwater platform inertial navigation calibration method of the present application includes: S101, releasing multiple buoys, and after the buoys are exposed to the water surface, receiving satellite positioning signals for positioning; S103, the underwater platform continuously sends interrogation signals through the bow hydroacoustic transducer and the stern hydroacoustic transducer; after the buoys receive the interrogation signals, they send satellite positioning information and response signals back to the underwater platform; S105, according to the satellite positioning information and the hydroacoustic positioning information, calculating the coordinates of the bow hydroacoustic transducer and the stern hydroacoustic transducer; S107, according to the coordinates of the bow hydroacoustic transducer and the stern hydroacoustic transducer, obtaining the real-time coordinates and heading of the inertial navigation system, and calibrating the inertial navigation system according to the obtained real-time coordinates and heading.

[0061] On the one hand, this application can solve the problems of long-endurance underwater carrier platforms needing to surface, poor concealment, and needing to operate in an environment where they are deployed in advance; on the other hand, it solves the problem of large technical errors in underwater GNSS (Global Navigation Satellite System) and improves the accuracy of inertial navigation calibration.

[0062] Figure 2 This is a schematic diagram of the double-difference underwater positioning and inertial navigation calibration of the vehicle based on the buoy array in this application, as shown in Figure 2 As shown, underwater carrier platform 12 relies primarily on an inertial navigation system 15 for long-term positioning. A bow acoustic transducer 13 and a stern acoustic transducer 14 are mounted on the bow of underwater carrier platform 12. Bow and stern acoustic transducers 13 and 14 are used for underwater acoustic communication and inertial navigation calibration. Buoy 11 is positioned using GNSS satellites 10.

[0063] Figure 3is a schematic diagram of the buoy structure, as shown in Figure 3 As shown, buoy 11 integrates GNSS and USBL technologies. GNSS is used to obtain the precise position of buoy 11. The USBL's acoustic transponder and acoustic communication module then transmit the buoy's position and its relative position to the carrier back to the underwater carrier platform 12, extending GNSS functionality underwater. Buoy 11 includes a GNSS positioning module 112, a GNSS antenna 111, an underwater acoustic communication module 113, and an underwater acoustic transponder 114. Buoy 11 is positioned using the GNSS positioning module 112 and GNSS antenna 111. The underwater acoustic transponder 114 is used to receive interrogation signals sent by the underwater acoustic transducer. Buoy 11 transmits positioning information and response signals to the underwater platform via the underwater acoustic communication module 113 and the underwater acoustic transponder 114.

[0064] The underwater platform inertial navigation calibration method of the present application includes the following steps:

[0065] (1) If Figure 4 and Figure 5 As shown, after entering the inertial navigation calibration process, four buoys are released sequentially according to a specific route. The route is the route of the underwater carrier platform. Compared to hovering, the underwater carrier platform continuously moves forward at an economical speed, consumes less energy, and is simpler to control. Some underwater carrier platforms cannot even hover due to lack of buoyancy adjustment capabilities. Therefore, this application designs a route that allows the underwater carrier platform to operate as close as possible to the geometric configuration of several buoy arrays. Compared to straight lines or round-trip routes, the HDOP (horizontal dilution of precision) will be smaller and the positioning accuracy will be higher.

[0066] (2) After the buoy emerges from the water, it receives GNSS signals for positioning.

[0067] (3) If Figure 5 As shown, the transducers at the bow and stern of the underwater carrier platform continuously send interrogation signals.

[0068] (4) After receiving the interrogation signal, the hydroacoustic transponder in the buoy immediately feeds back the response signal and converts the GNSS positioning information corresponding to the time t received by the interrogation signal into an acoustic signal and transmits it back to the underwater carrier platform.

[0069] (5) After receiving the signal, the double difference solution program is executed to calculate the heading and position of the underwater carrier platform. The program flow is as follows: Figure 6 The detailed steps are as follows:

[0070] Step ①, assume that the coordinates of the underwater acoustic transducer at any time k are , the position of the buoy's hydroacoustic transponder is , the round trip time of the acoustic ranging signal is , the speed of sound is C, then the basic observation equation from i to j is:

[0071]

[0072] in, is the geometric distance from i to j, i represents the transducer, j represents the buoy, is the distance observation value, is the sound velocity measurement error, is the underwater acoustic transducer delay error, is the underwater acoustic transponder delay error, is the random error of acoustic ranging, i represents the underwater acoustic transducer, and j represents the buoy;

[0073] The position of the inertial navigation system on the underwater platform is converted to the position on the underwater acoustic transducer: ,but The error equation obtained by linearizing the observation equation is:

[0074]

[0075] in, , , is the coordinate correction number; if the variance of the epoch observer is , one observation period t is one epoch, and the unit weight variance is , a random model can be constructed:

[0076]

[0077] in is the incident angle between buoy j and transducer i, then the variance-covariance matrix for:

[0078]

[0079] The first buoy that meets the preset conditions is selected as the reference buoy; for example, as the reference buoy, the buoy with the largest elevation angle or the strongest acoustic signal quality can be selected, or the two standards (elevation angle and acoustic signal quality) can be weighted to calculate a result value, and the buoy with the largest result value is used as the reference buoy, recorded as reference buoy 1.

[0080] Step ②: When the underwater acoustic transducer observes buoy j and the reference buoy synchronously, the difference between the observation equations of buoy j and the reference buoy can eliminate the transducer delay error and greatly reduce the error of the sound velocity measurement system. ,Right now

[0081] The single difference between buoys can be obtained The observation equation is:

[0082]

[0083] in, Represents the single difference symbol of the transponder difference between buoys, is the sound velocity measurement error of buoy j, is the sound velocity measurement error of the reference buoy, is the difference in observations between buoy j and the reference buoy, is the observation matrix composed of direction cosines, dX is the coordinate correction number, is the time delay error between buoy j and the reference buoy, is the random error of acoustic ranging;

[0084] Assume the single difference conversion factor between buoys:

[0085]

[0086] According to the error propagation law, the variance-covariance matrix of the single difference between buoys is for:

[0087]

[0088] Step ③: When the bow and stern hydroacoustic transducers synchronously observe the buoy j, the time delay errors of the transducer and the transponder can be eliminated at the same time, and the sound velocity measurement error can be greatly reduced. Thus, the double-difference observation equation is obtained:

[0089]

[0090] in, is the double difference symbol;

[0091] Variance-covariance matrix of single differences between buoys for:

[0092]

[0093] Step ④, the weighted least squares model is:

[0094]

[0095] Among them, it is assumed that the observation model is linear, that is, there is a least squares model between the observation value L and the state X, L is the observation value, A is the coefficient matrix, X is the state vector, v is the observation value residual, and E(v)=0 is the least squares assumption. is the unit weighted error, P is the weight matrix of each observation equation;

[0096] The solution is obtained under the least squares criterion, and the double-difference observation equation and the stochastic model are introduced to calculate the geometric coordinates of the bow and stern hydroacoustic transducers.

[0097] Step 5: The transducer and the inertial navigation system can be considered to be rigidly connected, that is, the relative positional relationship between the bow and stern acoustic transducers and the inertial navigation system is fixed and known. The computing module of the underwater carrier platform converts the geometric coordinates of the bow and stern acoustic transducers to obtain the real-time high-precision coordinates and heading of the inertial navigation system.

[0098] Step 6: Send the obtained real-time coordinates and heading to the inertial navigation system, and the inertial navigation system will be calibrated according to the received real-time coordinates and heading.

[0099] (6) After completing the inertial navigation calibration, recover the buoy.

[0100] The high-precision underwater platform inertial navigation calibration method for a GNSS / hydroacoustic buoy array provided in this application includes the following steps: after a carrier arrives at a deep-sea operating area, it adopts a specific route, releases buoys, and waits for the buoys to surface to receive and record continuously valid GNSS information; after all buoys are released, the underwater platform continuously transmits interrogation signals via the bow and stern USBL transducers; upon receiving the interrogation signals, the buoys transmit the corresponding GNSS information and response signals back to the underwater platform. By integrating the GNSS information and the USBL hydroacoustic positioning information, the internal navigation computer of the underwater platform's navigation system completes a double-difference underwater positioning process, deriving the positions of the bow and stern USBL transducers and the underwater platform's heading information. The transducers and inertial navigation system can be considered to be rigidly connected (i.e., their relative positional relationship is fixed and known). Therefore, the geometric coordinates of the bow and stern transducers can be used to obtain the real-time, high-precision coordinates and heading of the inertial navigation system through coordinate conversion.

[0101] In this application, the buoy has its own GNSS, which makes it convenient to obtain initial positioning information with high accuracy. As a supporting equipment for the underwater carrier platform, the buoy does not need to be deployed in advance, has high concealment, and has a free operating range, breaking through the limitations of the operating area. Based on the double-difference underwater acoustic positioning technology, it solves the problems of large underwater positioning errors and limited accuracy, and improves the accuracy of inertial navigation calibration.

[0102] The present application also provides an underwater platform inertial navigation calibration device, comprising: a plurality of buoys, the buoys floating on the water surface, used to receive satellite positioning signals for positioning; an underwater platform, used to continuously send inquiry signals through a bow hydroacoustic transducer and a stern hydroacoustic transducer; the buoys are used to send satellite positioning information and a response signal back to the underwater platform after receiving the inquiry signal; the underwater platform is used to: calculate the coordinates of the bow hydroacoustic transducer and the stern hydroacoustic transducer according to the satellite positioning information and the hydroacoustic positioning information; calculate the coordinates of the bow hydroacoustic transducer and the stern hydroacoustic transducer according to the bow hydroacoustic transducer .... The coordinates of the bow and stern acoustic transducers are converted to obtain the real-time coordinates and heading of the inertial navigation system, and the inertial navigation system is calibrated according to the obtained real-time coordinates and heading; the relative positional relationship between the bow and stern acoustic transducers and the inertial navigation system is fixed and known, and the computing module of the underwater platform converts the geometric coordinates of the bow and stern acoustic transducers to obtain the real-time coordinates and heading of the inertial navigation system, and sends the obtained real-time coordinates and heading to the inertial navigation system; the inertial navigation system is calibrated according to the received real-time coordinates and heading.

[0103] In this application, the embodiment of the underwater platform inertial navigation calibration device is basically similar to the embodiment of the underwater platform inertial navigation calibration method. For relevant details, please refer to the introduction of the embodiment of the underwater platform inertial navigation calibration method.

[0104] The present application also provides an underwater carrier platform, which uses any of the above-mentioned underwater platform inertial navigation calibration methods to calibrate the inertial navigation system.

[0105] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the underwater platform inertial navigation calibration method. The computer-readable storage medium may include, but is not limited to, any type of disk, including floppy disks, optical disks, DVDs, CD-ROMs, microdrives and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic or optical cards, nanosystems (including molecular memory ICs), or any other type of medium or device suitable for storing instructions and / or data.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for calibrating an underwater platform inertial navigation system, characterized in that: include: Release multiple buoys, and after the buoys emerge from the water, they receive satellite positioning signals for positioning; The underwater platform continuously sends interrogation signals through the bow and stern hydroacoustic transducers; after receiving the interrogation signals, the buoy sends satellite positioning information and a response signal back to the underwater platform; The coordinates of the bow and stern hydroacoustic transducers are calculated based on the satellite positioning information and the hydroacoustic positioning information, including: Step 1: Assume that the coordinates of the underwater acoustic transducer at any time k are , the position of the buoy's hydroacoustic transponder is , the round trip time of the acoustic ranging signal is , the speed of sound is C, then the basic observation equation from i to j is: in, is the geometric distance from i to j, is the distance observation value, is the sound velocity measurement error, is the underwater acoustic transducer delay error, is the underwater acoustic transponder delay error, is the random error of acoustic ranging, i represents the underwater acoustic transducer, and j represents the buoy; The position of the inertial navigation system on the underwater platform is converted to the position on the underwater acoustic transducer: ,but The error equation obtained by linearizing the observation equation is: in, , , is the coordinate correction number; if the variance of the epoch observer is , the unit weight variance is , a random model can be constructed: in is the incident angle between buoy j and transducer i, then the variance-covariance matrix for: Selecting the first buoy that meets the preset conditions as the reference buoy; Step 2: When the underwater acoustic transducer observes the reference buoy and buoy j synchronously, the difference between the observation equations of buoy j and the reference buoy can eliminate the transducer delay error and greatly reduce the error of the sound velocity measurement system. ,Right now The single-difference observation equation between buoys is obtained as follows: in, Represents the single difference symbol of the transponder difference between buoys, is the sound velocity measurement error of buoy j, is the sound velocity measurement error of the reference buoy, is the difference in observations between buoy j and the reference buoy, is the observation matrix composed of direction cosines, dX is the coordinate correction number, is the time delay error between buoy j and the reference buoy, is the random error of acoustic ranging; Assume the single difference conversion factor between buoys: According to the error propagation law, the variance-covariance matrix of the single difference between buoys is for: Step 3: When the bow and stern hydroacoustic transducers synchronously observe the buoy j, the time delay errors of the transducer and the transponder can be eliminated at the same time, and the sound velocity measurement error can be greatly reduced. Thus, the double-difference observation equation is obtained: in, is the double difference symbol; Variance-covariance matrix of single differences between buoys for: Step 4: The weighted least squares model is: Among them, L is the observation value, A is the coefficient matrix, X is the state vector, v is the observation value residual, and E(v)=0 is the least squares assumption. is the unit weighted error, P is the weight matrix of each observation equation; Solve the problem under the least squares criterion, bring in the double-difference observation equation and the stochastic model, and calculate the geometric coordinates of the bow and stern hydroacoustic transducers. The real-time coordinates and heading of the inertial navigation system are obtained according to the coordinates of the bow and stern hydroacoustic transducers, and the inertial navigation system is calibrated according to the obtained real-time coordinates and heading; the relative positional relationship between the bow and stern hydroacoustic transducers and the inertial navigation system is fixed and known, and the computing module of the underwater platform converts the geometric coordinates of the bow and stern hydroacoustic transducers to obtain the real-time coordinates and heading of the inertial navigation system, and sends the obtained real-time coordinates and heading to the inertial navigation system, and the inertial navigation system is calibrated according to the received real-time coordinates and heading.

2. The underwater platform inertial navigation calibration method according to claim 1, characterized in that: The method comprises releasing a plurality of buoys, and receiving satellite positioning signals for positioning after the buoys emerge from the water surface, including: the underwater platform travels according to a preset route, releasing a plurality of buoys in sequence, and receiving satellite positioning signals for positioning after the buoys emerge from the water surface.

3. The underwater platform inertial navigation calibration method according to claim 2, characterized in that: The buoy includes a satellite signal positioning module, an antenna, a hydroacoustic communication module and a hydroacoustic transponder. The buoy is positioned by the satellite signal positioning module and the antenna. The hydroacoustic transponder is used to receive the inquiry signal sent by the hydroacoustic transducer. The buoy transmits the positioning information and the response signal to the underwater platform through the hydroacoustic communication module and the hydroacoustic transponder.

4. The underwater platform inertial navigation calibration method according to claim 1, characterized in that: Select the buoy with the largest elevation angle or the strongest acoustic signal quality as the reference buoy; or determine the reference buoy based on the elevation angle and acoustic signal quality.

5. The underwater platform inertial navigation calibration method according to any one of claims 1 to 3, characterized in that: It also includes recovering the buoy after the inertial navigation system is calibrated.

6. An underwater platform inertial navigation calibration device, characterized in that: include: A plurality of buoys, each of which floats on the water surface and is used to receive satellite positioning signals for positioning; an underwater platform, configured to continuously send interrogation signals via a bow hydroacoustic transducer and a stern hydroacoustic transducer; The buoy is used to send satellite positioning information and a response signal back to the underwater platform after receiving the inquiry signal; The underwater platform is used to calculate the coordinates of the bow underwater acoustic transducer and the stern underwater acoustic transducer based on satellite positioning information and underwater acoustic positioning information; Assume that the coordinates of the underwater acoustic transducer at any time k are , the position of the buoy's hydroacoustic transponder is , the round trip time of the acoustic ranging signal is , the speed of sound is C, then the basic observation equation from i to j is: in, is the geometric distance from i to j, is the distance observation value, is the sound velocity measurement error, is the underwater acoustic transducer delay error, is the underwater acoustic transponder delay error, is the random error of acoustic ranging, i represents the underwater acoustic transducer, and j represents the buoy; The position of the inertial navigation system on the underwater platform is converted to the position on the underwater acoustic transducer: ,but The error equation obtained by linearizing the observation equation is: in, , , is the coordinate correction number; if the variance of the epoch observer is , the unit weight variance is , a random model can be constructed: in is the incident angle between buoy j and transducer i, then the variance-covariance matrix for: Selecting the first buoy that meets the preset conditions as the reference buoy; When the underwater acoustic transducer observes the reference buoy and buoy j synchronously, the difference between the observation equations of buoy j and the reference buoy can eliminate the transducer delay error and greatly reduce the error of the sound velocity measurement system. ,Right now The single-difference observation equation between buoys is obtained as follows: in, Represents the single difference symbol of the transponder difference between buoys, is the sound velocity measurement error of buoy j, is the sound velocity measurement error of the reference buoy, is the difference in observations between buoy j and the reference buoy, is the observation matrix composed of direction cosines, dX is the coordinate correction number, is the time delay error between buoy j and the reference buoy, is the random error of acoustic ranging; Assume the single difference conversion factor between buoys: According to the error propagation law, the variance-covariance matrix of the single difference between buoys is for: When the bow and stern hydroacoustic transducers synchronously observe the buoy j, the time delay errors of the transducer and the transponder can be eliminated at the same time, and the sound velocity measurement error can be greatly reduced. Thus, the double-difference observation equation is obtained: in, is the double difference symbol; Variance-covariance matrix of single differences between buoys for: The weighted least squares model is: Among them, L is the observation value, A is the coefficient matrix, X is the state vector, v is the observation value residual, and E(v)=0 is the least squares assumption. is the unit weighted error, P is the weight matrix of each observation equation; Solve the problem under the least squares criterion, bring in the double-difference observation equation and the stochastic model, and calculate the geometric coordinates of the bow and stern hydroacoustic transducers. The real-time coordinates and heading of the inertial navigation system are obtained according to the coordinates of the bow and stern hydroacoustic transducers, and the inertial navigation system is calibrated according to the obtained real-time coordinates and heading; the relative positional relationship between the bow and stern hydroacoustic transducers and the inertial navigation system is fixed and known, and the computing module of the underwater platform converts the geometric coordinates of the bow and stern hydroacoustic transducers to obtain the real-time coordinates and heading of the inertial navigation system, and sends the obtained real-time coordinates and heading to the inertial navigation system, and the inertial navigation system is calibrated according to the received real-time coordinates and heading.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

8. An underwater carrying platform, characterized in that: The underwater carrier platform calibrates the inertial navigation system using the underwater platform inertial navigation calibration method described in any one of claims 1 to 5.

Images