Underwater navigation and communication integrated position service system and method

Abstract

The present invention belongs to the field of marine underwater positioning, navigation and timing. Disclosed are an underwater navigation and communication integrated position service system and method. The system comprises a buoy base station, a submerged buoy base station, a seabed base station and a shore-based operation and control unit, and the system utilizes a three-dimensional base station network observation mode combining the buoy base station, the submerged buoy base station and the seabed base station. The position service system and method in the present invention have the capabilities of underwater acoustic navigation and communication, satellite positioning and communication, atomic clock timekeeping, hydrological measurement and responding to instructions of a shore-based operation and control unit, have the functions of autonomous, real-time and online base station position and clock calibration and sound velocity field correction, have the functions of base station position and clock calibration, and sound velocity field correction and control based on the shore-based operation and control unit, and can expand the range and functions of underwater position services, and provide accurate positioning, navigation and timing services for water-surface / underwater users.

Description

An underwater navigation and communication integrated position service system and method TECHNICAL FIELD

[0001] The present application belongs to the field of marine underwater positioning, navigation and timing, and particularly relates to an underwater navigation and communication integrated position service system and method. BACKGROUND

[0002] The role of the marine space-time reference network is to transfer the global unified space-time reference to the surface, interior and bottom of the ocean. The underwater position service system is an important infrastructure, which provides underwater positioning, navigation and timing support for seabed resource investigation and development, marine disaster prevention, marine safety, deep sea scientific research, and has great scientific significance and engineering practical value. However, the construction of the underwater position service system faces many technical problems and challenges.

[0003] At present, the underwater position service system has not organically integrated marine environment perception, communication and operation control, which restricts the service accuracy, continuity, availability and reliability of the underwater position.

[0004] SUMMARY

[0005] To solve the above technical problems, the present application provides an underwater navigation and communication integrated position service system and method, which constructs a water acoustic communication and satellite communication link to realize marine space-time multi-element comprehensive observation and shore-based operation and control, expands the range and function of underwater position service, and provides accurate positioning, navigation and timing service for surface and underwater users.

[0006] To achieve the above purpose, the technical scheme of the present application is as follows:

[0007] An underwater navigation and communication integrated position service system, comprising a buoy base station, a submerged buoy base station, a seabed base station and a shore-based operation and control unit, the system adopts a three-dimensional base station network observation mode combining the buoy base station, the submerged buoy base station and the seabed base station;

[0008] The buoy base station comprises a frame one, a floating body one is installed on the top of the frame one, a power supply battery cabin is installed on the bottom of the floating body one, a GNSS board card antenna and a two-way satellite communication module are installed on the top of the floating body one, a medium-low frequency navigation and communication sonar one and a temperature-salinity-depth instrument one are installed on the bottom of the frame one, a control and data acquisition and processing module one, a MEMS three-axis gyroscope one, an accelerometer one and a power supply unit one are installed in the power supply battery cabin;

[0009] The submersible base station comprises a frame two, a glass float group one is mounted in the middle of the frame two, an acoustic Doppler current profiler one and a medium-low frequency navigation communication sonar two are mounted on the top of the frame two, and a CTD two is mounted on the bottom of the frame two; the glass float group one is internally provided with a control and data acquisition processing module two, a chip-level atomic clock one, a MEMS three-axis gyroscope two, an accelerometer two, a magnetometer and a power supply unit two; the frame two is mounted on the anchor cable, and an acoustic releaser one is mounted between the frame two and the anchor cable;

[0010] The seabed base station comprises a frame three, a glass float group two is mounted in the middle of the frame three, an acoustic Doppler current profiler two, a medium-low frequency navigation communication sonar three and a CTD three are mounted on the top of the frame three, and the glass float group two is internally provided with a control and data acquisition processing module three, a chip-level atomic clock two and a power supply unit three; the frame three is mounted on the ballast anchor, and an acoustic releaser two is mounted between the frame three and the ballast anchor;

[0011] The shore-based operation and control unit is composed of a two-way satellite communication terminal, a server and system operation and control software, and is configured to automatically receive the base station network data returned by the buoy base station in a long-term manner, including the system working state of the base station network, and to perform two-way handshake interactive data communication and instruction issuing, and to issue relevant working mode switching instructions to the base station network, so as to realize remote control function.

[0012] An underwater navigation and communication integrated location service method, which adopts an underwater navigation and communication integrated location service system as described above, comprises base station laying, base station calibration, base station service and base station recovery, and specifically comprises the following steps:

[0013] Step (1): Before the submersible base station is laid, the clock bias of the chip-level atomic clock one thereof is calibrated by using GNSS timing, and the MEMS three-axis gyroscope two, the accelerometer two and the magnetometer thereof are calibrated; before the seabed base station is laid, the clock bias of the chip-level atomic clock two thereof is calibrated by using GNSS timing; after the submersible base station is laid, the three-dimensional geodetic coordinates of the anchor point thereof are determined by using the acoustic releaser one multi-point positioning, and then the buoy base station and the seabed base station are laid; the submersible base station is laid at the depth closest to the sound channel axis in the base station network sea area;

[0014] Step (2): After the base station network is laid, the GNSS-acoustic combined positioning technology based on the surveying ship is adopted to measure the coordinate initial value of the acoustic center of the medium-low frequency navigation communication sonar two of the submersible base station and the coordinate initial value of the acoustic center of the medium-low frequency navigation communication sonar three of the seabed base station, and the coordinate initial values are respectively input to the control and data acquisition processing module two and the control and data acquisition processing module three; then the surveying ship returns or goes to other sea areas for operation;

[0015] Step (3): The base station network carries out long-term and continuous measurement according to the pre-set work plan and sampling frequency, and the shore-based operation and control unit sends instructions through satellite and underwater acoustic communication. The base station network receives and responds to the instructions of the shore-based operation and control unit, and switches the working mode according to the instructions, including switching the working / sleeping mode, autonomous position service / shore-based operation and control position service mode, sonar active ranging / passive ranging mode, ocean temperature and salinity depth flow observation data return mode, and base station system state query mode.

[0016] Step (4): After the service of the base station network is completed, the acoustic release one and the acoustic release two are released, so that the subsurface buoy base station and the seabed base station float to the sea surface, and the recovery of the buoy base station, the subsurface buoy base station and the seabed base station is carried out.

[0017] In the above scheme, during the autonomous position service mode of the base station network, autonomous real-time online base station position and clock calibration is carried out; the buoy base station obtains its instantaneous coordinates by real-time precise point positioning based on the Beidou-3 satellite precise point positioning service signal PPP-B2b and the Galileo satellite high-precision service signal HAS, and calibrates its sonar clock by GNSS timing; the subsurface buoy base station and the seabed base station calibrate chip-level atomic clock one and chip-level atomic clock two by underwater acoustic timing of the buoy base station, and periodically measure the underwater acoustic time delay between the subsurface buoy base station and the seabed base station and the buoy base station and carry out time synchronization; the subsurface buoy base station autonomously calculates the instantaneous coordinates of its sonar acoustic center by measuring the mutual underwater acoustic time delay between the subsurface buoy base station and the seabed base station and / or the buoy base station, the observation values of the temperature and salinity depth instrument two and the MEMS three-axis gyroscope two, the accelerometer two and the magnetometer; each base station broadcasts its position and clock to underwater users through underwater acoustic communication; the buoy base station constructs the prior sound speed field correction number by using its own temperature and salinity depth observation, the temperature and salinity depth flow observation of each subsurface buoy base station and seabed base station, and the underwater acoustic time delay between the buoy base station and each subsurface buoy base station and seabed base station, and broadcasts the prior sound speed field correction number to underwater users and subsurface buoy base stations through underwater acoustic communication; the subsurface buoy base station broadcasts the prior sound speed field correction number to underwater users through underwater acoustic communication; the underwater users correct the prior sound speed field by using the underwater acoustic time delay measurement value of the navigation terminal and the base station network, and the received base station position, clock and prior sound speed field correction number, and carry out positioning, navigation and timing.

[0018] During the base station network switching to the shore-based operation and control location service mode, the base station location and clock calibration and the prior sound speed field construction are performed based on the shore-based operation and control unit; the water acoustic time delay and the temperature-salinity-depth flow data measured by each of the submersible base station and the seabed base station between the base stations are transmitted to the buoy base station through the acoustic water acoustic communication between the base stations, and are transmitted to the shore-based operation and control unit together with the water acoustic time delay and the temperature-salinity-depth data measured by the buoy base station between the base stations through the satellite communication of the buoy base station for processing and calculation to obtain the correction numbers of the base station location, the clock and the prior sound speed field, and then the correction numbers of the base station location, the clock and the sound speed field are transmitted to the buoy base station by the shore-based operation and control unit, and are transmitted to each of the submersible base station and the seabed base station by the buoy base station through the acoustic water acoustic communication between the buoy base station and each of the submersible base station and the seabed base station, and the correction numbers of the base station location, the clock and the prior sound speed field are broadcasted by each of the submersible base station and the seabed base station through the acoustic water acoustic communication thereof for use by the underwater users.

[0019] In the above scheme, when the base station network is switched to the acoustic active ranging mode according to the operation and control instruction, the inquiry-response mode is adopted between the underwater user navigation terminal and the base station network, that is, the underwater user navigation terminal sends an inquiry signal, and the base station network sends a response signal after receiving the inquiry signal; when the base station network is switched to the acoustic passive ranging mode according to the operation and control instruction, the synchronous mode is adopted between the underwater user navigation terminal and the base station network, that is, the base station network synchronously broadcasts a ranging signal, and the underwater user navigation terminal receives the ranging signal;

[0020] When the base station network is switched to the ocean temperature-salinity-depth flow observation data return mode according to the operation and control instruction, long-term and autonomous measurement of the water acoustic positioning, navigation, timing and ocean environment data is performed according to the pre-setting, and is transmitted to the buoy base station through the underwater acoustic communication mode, and then is transmitted to the shore-based operation and control unit receiving end through the satellite communication of the buoy base station; in addition, the data return time interval can be increased from the hour level to the minute level or near real-time according to the operation and control instruction or the underwater user demand.

[0021] In the above scheme, the communication mode of the system is divided into two parts of the satellite communication link and the water acoustic communication link; the satellite communication link covers the shore-based operation and control unit to the buoy base station, and the water acoustic communication link adopts the master-slave communication mode and covers the buoy base station to the submersible base station and the seabed base station; in the acoustic communication process between the base station network and the shore-based operation and control unit and the underwater user terminal, data encryption and compression are performed.

[0022] In the further technical scheme, the satellite communication link adopts the bidirectional asynchronous communication working mode and transmits data based on the Beidou-3 point-to-point short message or the Tian Tong communication satellite; the satellite communication topology structure is that the buoy base station is the master and the shore-based operation and control unit is the slave, and a standby state is kept all day long; the satellite communication is divided into two working modes according to the demand, and the shore-based operation and control unit notifies the buoy base station to switch the two working modes through the instruction issuing mode.

[0023] Mode 1: The buoy base station satellite communication module remains in the power-on state, passively waits for the command sent by the shore base operation and control unit, and performs actions and feedbacks data according to the command feedback;

[0024] Mode 2: The buoy base station satellite communication module is closed and opened in a timing manner, and queries the new command and returns data sent by the shore base operation and control unit in a timing manner.

[0025] In a further technical solution, the underwater acoustic communication link adopts a bidirectional asynchronous communication mode for point-to-point data transmission of the sonar; the underwater acoustic communication topology is a star network operating in a master-slave mode, the buoy base station is a central host node, and the submersible base station and the seabed base station are peripheral slave nodes, each of which is connected to the central host node through an underwater acoustic communication channel; the central host node adopts a centralized communication control strategy, and the peripheral slave nodes cannot directly communicate with each other and must communicate through the central host node; in this mode, all peripheral slave nodes work in a passive waiting mode, the central host node initiates active handshake and command issuing, and any peripheral slave node performs command execution and feedback after receiving the command, and completes a communication process after completing bidirectional handshake interaction.

[0026] In the above solution, when the buoy base station cannot obtain the sea current observation of each submersible base station and seabed base station and the underwater acoustic time delay between the buoy base station and each submersible base station and seabed base station, it only uses the temperature, salinity and depth observation of each submersible base station and seabed base station and itself to construct a prior sound speed field correction, and the specific method is as follows:

[0027] First, calculate the sound speed from the seawater temperature, salinity and pressure;

[0028] Then, the sound speed profile parameters C axis , ε, z axis , B are fitted by the following formula: C(z) = C axis [1 + ε(η + e -η -1)];

[0029] Wherein, z is the depth of the base station temperature and salinity depth gauge, C(z) is the calculated sound speed value at depth z, C axis represents the sound speed at the channel axis, ∈ represents the sound speed disturbance coefficient, η represents the dimensionless distance, z axis is the channel axis depth, and B is the channel scale thickness.

[0030] Finally, the sound speed profile parameters C axis , ∈, z axis , B are broadcast to underwater users, and the underwater users correct their prior sound speed field after receiving them.

[0031] In the above scheme, the submersible base station adopts a single-point tightening type anchor structure, which is used to anchor the whole submersible base station and is recycled as a whole after the service is completed; when the submersible base station cannot measure the water acoustic time delay with the buoy base station and the seabed base station, the submersible base station performs independent real-time online position self-calibration, and the specific method is as follows:

[0032] Firstly, the pitch angle and the roll angle are calculated by using the observation value of the second accelerometer, and the azimuth angle is calculated by using the observation value of the magnetometer;

[0033] Then, the real-time position of the submersible base station is calculated by the following formula:

[0034] In the formula, E, N and U are east, north and elevation direction coordinates of the second medium-low frequency navigation and communication sonar of the submersible base station relative to the anchor point, L is the cable length from the second medium-low frequency navigation and communication sonar of the submersible base station to the anchor point, and alpha, beta and gamma are the pitch angle, the roll angle and the azimuth angle of the submersible base station, respectively.

[0035] Finally, the three-dimensional geodetic coordinates of the second medium-low frequency navigation and communication sonar of the submersible base station are calculated by the three-dimensional geodetic coordinates of the anchor point and E, N and U.

[0036] Through the above technical scheme, the underwater navigation and communication integrated position service system and method provided by the present application have the following beneficial effects:

[0037] The underwater navigation and communication integrated position service system provided by the present application has the capabilities of underwater acoustic navigation and communication, satellite positioning and communication, atomic clock time keeping, temperature-salinity-depth flow measurement and response to the instructions of the shore-based operation and control unit, has the functions of autonomous real-time online base station position and clock calibration and sound speed field correction, has the functions of base station calibration, sound speed field correction and control based on the shore-based operation and control unit, and contains a buoy base station, a submersible base station and a seabed base station. By constructing underwater acoustic communication and satellite communication links, the range and functions of underwater position service are expanded, and accurate positioning, navigation and timing services can be provided for surface and underwater users. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description.

[0039] Fig. 1 is a schematic diagram of an underwater navigation and communication integrated position service system disclosed by the embodiment of the present application.

[0040] Fig. 2 is a schematic diagram of a buoy base station;

[0041] Fig. 3 is a schematic diagram of a submersible base station;

[0042] Fig. 4 is a schematic diagram of a seabed base station.

[0043] In the figure, 1, frame one; 2, floating body one; 3, power battery cabin; 4, GNSS board card antenna; 5, two-way satellite communication module; 6, low-frequency navigation communication sonar one; 7, temperature-salinity-depth instrument one; 8, frame two; 9, glass float ball group one; 10, acoustic Doppler current profiler one; 11, low-frequency navigation communication sonar two; 12, temperature-salinity-depth instrument two; 13, acoustic release one; 14, frame three; 15, glass float ball group two; 16, acoustic Doppler current profiler two; 17, low-frequency navigation communication sonar three; 18, temperature-salinity-depth instrument three; 19, acoustic release two; 20, ballast anchor. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application.

[0045] The present application provides an underwater navigation and communication integrated location service system, as shown in Figure 1, comprising a buoy base station, a subsurface buoy base station, a seabed base station and a shore-based operation and control unit, which adopts a three-dimensional networking observation mode combining the buoy base station, the subsurface buoy base station and the seabed base station.

[0046] As shown in Figure 2, the buoy base station comprises frame one 1, the top of which is provided with floating body one 2, the bottom of which is provided with power battery cabin 3, the top of which is provided with GNSS board card antenna 4 and two-way satellite communication module 5, the bottom of which is provided with low-frequency navigation communication sonar one 6 and temperature-salinity-depth instrument one 7, and the power battery cabin 3 is provided with control and data acquisition and processing module one, MEMS three-axis gyroscope one, accelerometer one and power supply unit one.

[0047] The functions of the buoy base station are as follows:

[0048] (1) sonar measurement and instruction and data communication of the sea surface node, used for water acoustic positioning time delay measurement, water acoustic time service and underwater multi-node water acoustic communication;

[0049] (2) satellite positioning and communication, used for two-way data and command transmission with the shore-based operation and control unit;

[0050] (3) measurement of sea surface temperature-salinity-depth / sound velocity data.

[0051] As shown in Fig. 3, the submersible base station comprises a frame 8, a glass float group 9 is mounted in the middle of the frame 8, an acoustic Doppler current profiler 10 and a medium-low frequency navigation communication sonar 11 are mounted on the top of the frame 8, a CTD 12 is mounted on the bottom of the frame 8, a control and data acquisition processing module 2, a chip-level atomic clock 1, a MEMS three-axis gyroscope 2, an accelerometer 2, a magnetometer and a power supply unit 2 are mounted in the glass float group 9; the frame 2 is installed on the anchor cable, and an acoustic release 13 is installed between the frame 2 and the anchor cable.

[0052] The functions of the submersible base station are as follows:

[0053] (1) Water acoustic measurement and communication of the medium-low frequency sonar, which is used for water acoustic positioning and instruction and data transmission;

[0054] (2) Measurement of upper ocean environmental parameters, including profile current data and node CTD / sound velocity data;

[0055] (3) Measurement of self attitude change data.

[0056] As shown in Fig. 4, the seabed base station comprises a frame 14, a glass float group 15 is mounted in the middle of the frame 14, an acoustic Doppler current profiler 16, a medium-low frequency navigation communication sonar 17 and a CTD 18 are mounted on the top of the frame 14, a control and data acquisition processing module 3, a chip-level atomic clock 2 and a power supply unit 3 are mounted in the glass float group 15, and the frame 14 is installed on the ballast anchor 20, and an acoustic release 19 is installed between the frame 14 and the ballast anchor 20.

[0057] The functions of the seabed base station are as follows:

[0058] (1) Water acoustic measurement and communication of the medium-low frequency sonar, which is used for water acoustic positioning and instruction and data transmission;

[0059] (2) Measurement of seabed environmental parameters, including profile current data, seabed CTD / sound velocity;

[0060] (3) Measurement of self attitude change data.

[0061] The control and data acquisition processing modules of the base stations of the system are responsible for collecting and processing the sensor data of the base stations.

[0062] The shore base operation and control unit is composed of a two-way satellite communication terminal, a server and system operation and control software, according to the settings, the base station network data returned by the buoy base station is automatically received for a long time, including the system working state of the base station network, and the two-way handshake interactive data communication and instruction issuing are carried out, the related working mode switching instructions are issued to the base station network, and the remote control function is realized.

[0063] The functions of the two-way satellite communication terminal are as follows:

[0064] (1) Obtain the system working state of the base station network through satellite communication, and issue relevant observation instructions to the base station network to realize remote control function;

[0065] (2) Receive the data returned by the base station network through satellite communication, and have the functions of bidirectional data interaction and breakpoint resume.

[0066] An underwater navigation and communication integrated location service method adopts the underwater navigation and communication integrated location service system as above, and comprises base station laying, base station calibration, base station service and base station recovery, and specifically comprises the following steps:

[0067] Step (1): Before the laying of the subsurface base station, the clock deviation of the chip-level atomic clock one is calibrated by using GNSS timing, and the MEMS three-axis gyroscope two, the accelerometer two and the magnetometer are calibrated; before the laying of the seabed base station, the clock deviation of the chip-level atomic clock two is calibrated by using GNSS timing; after the laying of the subsurface base station, the three-dimensional geodetic coordinates of the anchor point of the subsurface base station are determined by using the acoustic release one multi-point positioning, and then the float base station and the seabed base station are laid; the subsurface base station is laid at the depth closest to the sound channel axis of the base station network sea area, i.e. at the place where the sound speed is the smallest in the depth direction;

[0068] Step (2): After the laying of the base station network is completed, the GNSS-acoustic combined positioning technology based on the surveying ship is adopted to determine the coordinate initial value of the acoustic center of the medium-low frequency navigation and communication sonar two of the subsurface base station and the coordinate initial value of the acoustic center of the medium-low frequency navigation and communication sonar three of the seabed base station, and input them into the control and data acquisition processing module two and the control and data acquisition processing module three respectively; then the surveying ship returns or goes to other sea areas for operation;

[0069] Step (3): The base station network carries out long-term and continuous measurement according to the pre-set working plan and sampling frequency, the shore-based operation and control unit sends instructions through satellite and underwater acoustic communication, the base station network receives and responds to the instructions of the shore-based operation and control unit, and carries out working mode switching according to the instructions, including switching working / sleeping mode, autonomous location service / shore-based operation and control location service mode, sonar active ranging / passive ranging mode, ocean temperature and salinity depth flow observation data return mode, base station system state query mode;

[0070] Step (4): After the service of the base station network is completed, the subsurface base station and the seabed base station are made to float to the sea surface by releasing the acoustic release one and the acoustic release two, and the float base station, the subsurface base station and the seabed base station are recovered.

[0071] Specifically, each working mode is as follows:

[0072] 1. During the base station network switching to the autonomous position service mode, the autonomous real-time online base station position and clock calibration is carried out; the buoy base station obtains its instantaneous coordinates by using the real-time precise point positioning based on the Beidou-3 satellite precise point positioning service signal PPP-B2b and the Galileo satellite high accuracy service signal HAS, and calibrates its sonar clock by using the GNSS timing; the submersible base station and the seabed base station respectively calibrate chip-level atomic clock one and chip-level atomic clock two by using the underwater acoustic timing of the buoy base station, and periodically measure the underwater acoustic time delay between the submersible base station and the seabed base station and the buoy base station and carry out time synchronization; the submersible base station autonomously calculates the instantaneous coordinates of the acoustic center of the sonar by using the mutual underwater acoustic time delay measurement between the submersible base station and the seabed base station and / or the buoy base station, the observation values of the CTD two and the MEMS three-axis gyroscope two, the accelerometer two and the magnetometer; each base station broadcasts its position and clock to the underwater user through underwater acoustic communication; the buoy base station constructs the prior sound speed field correction by using its own temperature, salinity and depth observation, the temperature, salinity, depth and current observation of each submersible base station and seabed base station, and the underwater acoustic time delay between the buoy base station and each submersible base station and seabed base station, and broadcasts the prior sound speed field correction to the underwater user and the submersible base station through underwater acoustic communication; the underwater user corrects the prior sound speed field by using the underwater acoustic time delay measurement between the navigation terminal and the base station network, and the received base station position, clock and prior sound speed field correction, and carries out positioning, navigation and timing.

[0073] When the submersible base station cannot measure the underwater acoustic time delay with the buoy base station and the seabed base station, the submersible base station carries out independent real-time online position self-calibration, and the specific method is as follows:

[0074] Firstly, the pitch angle and the roll angle are calculated by using the observation values of the accelerometer two, and the azimuth angle is calculated by using the observation values of the magnetometer;

[0075] Then, the real-time position of the submersible base station is calculated by the following formula:

[0076] In the formula, E, N and U are respectively the east, north and elevation direction coordinates of the medium and low frequency navigation communication sonar two of the submersible base station relative to the anchor point, L is the cable length from the medium and low frequency navigation communication sonar two of the submersible base station to the anchor point, and α, β and γ are respectively the pitch angle, the roll angle and the azimuth angle of the submersible base station.

[0077] Finally, the three-dimensional geodetic coordinates of the medium and low frequency navigation communication sonar two of the submersible base station are calculated by the three-dimensional geodetic coordinates of the anchor point and E, N and U.

[0078] When the buoy base station cannot obtain ocean current observations from each moored base station and seabed base station, as well as the underwater acoustic time delay between itself and each moored base station and seabed base station, it constructs a priori sound velocity field corrections solely using the temperature, salinity, and depth observations from each moored base station and seabed base station, as well as its own. The specific method is as follows:

[0079] First, the speed of sound is calculated from seawater temperature, salinity, and pressure;

[0080] Then, the sound velocity profile parameter C is fitted using the following formula. axis ,∈,z axis B: C(z)=C axis [1+∈(η+e -η -1)];

[0081] Where z is the depth of the base station's temperature, salinity, and depth instrument, and C(z) is the calculated sound velocity at depth z. axis The z-axis represents the sound velocity at the duct axis, ε represents the sound velocity perturbation coefficient, η represents the dimensionless distance, and z axis B is the axial depth of the vocal tract, and B is the dimensional thickness of the vocal tract.

[0082] Finally, the sound speed profile parameter C axis , ε, z axis B is broadcast to underwater users, who then correct their prior sound velocity field.

[0083] 2. During the switch of the base station network to the shore-based operation and control location service mode, the shore-based operation and control unit performs base station location and clock calibration and constructs the a priori sound velocity field. The underwater acoustic delay and temperature, salinity, depth, and ocean current data between the base stations measured by each moored base station and the seabed base station are sent to the buoy base station through sonar-acoustic communication between the base stations. The underwater acoustic delay and temperature, salinity, and depth data between the base stations measured by the buoy base station and the satellite communication of the buoy base station are sent to the shore-based operation and control unit for processing and calculation to obtain the correction values ​​of the base station location, clock, and a priori sound velocity field. Then, the shore-based operation and control unit sends the correction values ​​of the base station location, clock, and sound velocity field to the buoy base station through satellite communication. The buoy base station sends the correction values ​​of the base station location, clock, and sound velocity field to each moored base station and the seabed base station through its sonar-acoustic communication with each moored base station and the seabed base station. Each moored base station and the seabed base station broadcasts the correction values ​​of the base station location, clock, and a priori sound velocity field through its sonar-acoustic communication for use by underwater users.

[0084] 3. When the base station network switches to the active sonar ranging mode according to the operation and control instruction, the underwater user navigation terminal and the base station network adopt the inquiry-response mode, that is, the underwater user navigation terminal sends an inquiry signal, and the base station network sends a response signal after receiving the inquiry signal; when the base station network switches to the passive sonar ranging mode according to the operation and control instruction, the underwater user navigation terminal and the base station network adopt the synchronous mode, that is, the base station network synchronously broadcasts a ranging signal, and the underwater user navigation terminal receives the ranging signal.

[0085] 4. When the base station network switches to the ocean temperature and salinity depth flow observation data return mode according to the operation and control instruction, the base station network is used for long-term and autonomous measurement of underwater acoustic positioning, navigation, timing and ocean environment data according to the pre-setting, and the data are transmitted to the buoy base station through underwater acoustic communication, and then transmitted to the shore base operation and control unit through satellite communication of the buoy base station; in addition, the base station network can increase the data return time interval from the hour level to the minute level or near real time according to the operation and control instruction or the underwater user demand.

[0086] 5. The base station system state query mode, the shore base operation and control unit sends a query instruction to the buoy base station, and then the buoy base station transmits the query instruction to each submersible base station and seabed base station, and each base station returns its state.

[0087] In the above several modes, the information transmission communication mode of the system is divided into satellite communication link and underwater acoustic communication link.

[0088] (1) Satellite communication link

[0089] The satellite communication link covers the shore base operation and control unit to the buoy base station, the satellite communication link adopts a bidirectional asynchronous communication mode, and transmits data based on Beidou-3 point-to-point short message or Tianhong communication satellite; the satellite communication topology structure is that the buoy base station is the host and the shore base operation and control unit is the slave, and they keep the all-weather standby state; the satellite communication is divided into two working modes according to the demand, and the shore base operation and control unit notifies the buoy base station to switch between the two working modes by means of instruction issuing:

[0090] Mode 1: The satellite communication module of the buoy base station keeps the power-on state and passively waits for the instruction sent by the shore base operation and control unit, and performs the action according to the instruction feedback and feeds back the data; in this mode, the buoy base station does not actively initiate communication with the shore base operation and control unit, and keeps the passive waiting mode, at this time, the shore base operation and control unit issues an instruction signal, the buoy base station performs a response action according to the instruction and distributes it to each underwater node for execution, and after receiving the feedback confirmation of the underwater node, returns the instruction execution feedback to the shore base operation and control unit;

[0091] Mode 2: The buoy base station satellite communication module is closed and powered on at a fixed time, and initiates a query of new commands and data transmission from the shore base operation and control unit. In this mode, the buoy base station communication unit is closed and powered on at a fixed time, and initiates a query of new commands and data transmission from the shore base operation and control unit. In this mode, the shore base operation and control unit remains in a long waiting state, and when a handshake request from the buoy base station is received, the command is issued and the data is transmitted. In this state, the shore base operation and control unit can still send relevant instructions to the shore base satellite communication terminal, which will be buffered in the shore base communication terminal, and will be issued to each underwater node after the sea surface buoy base station establishes a communication connection. The command execution will have a corresponding delay (e.g. more than 1 hour).

[0092] (2) Underwater acoustic communication link

[0093] The underwater acoustic communication link adopts a master-slave communication mode, covering the buoy base station to the submersible base station and the seabed base station. During the acoustic communication process between the base station network and the shore base operation and control unit and the underwater user terminal, data encryption and compression are performed.

[0094] The underwater acoustic communication link adopts a bidirectional asynchronous communication mode, and performs point-to-point data transmission of the sonar. The underwater acoustic communication topology is a star network, and operates in a master-slave mode. The buoy base station is the central host node, and the submersible base station and the seabed base station are peripheral slave nodes. The peripheral slave nodes are individually connected to the central host node through the underwater acoustic communication channel. The central host node adopts a centralized communication control strategy, and the peripheral slave nodes cannot directly communicate with each other and must communicate through the central host node. In this mode, all peripheral slave nodes work in a passive waiting mode, and the central host node initiates active handshake and command issuance. After receiving the command, any peripheral slave node performs command execution and feedback, and completes a communication process after completing bidirectional handshake interaction.

[0095] The above description of disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An underwater navigation and communication integrated location service system, characterized by, The system comprises a buoy base station, a subsurface buoy base station, a seabed base station and a shore base operation and control unit, and adopts a three-dimensional base station network observation mode combining the buoy base station, the subsurface buoy base station and the seabed base station; The buoy base station comprises a frame one, a floating body one is installed on the top of the frame one, a power supply battery cabin is installed on the bottom of the floating body one, a GNSS board card antenna and a two-way satellite communication module are installed on the top of the floating body one, a medium and low frequency navigation communication sonar one and a temperature-salinity-depth instrument one are installed on the bottom of the frame one, a control and data acquisition processing module one, a MEMS three-axis gyroscope one, an accelerometer one and a power supply unit one are installed in the power supply battery cabin; The subsurface buoy base station comprises a frame two, a glass float ball group one is installed in the middle of the frame two, an acoustic Doppler current profiler one and a medium and low frequency navigation communication sonar two are installed on the top of the frame two, a temperature-salinity-depth instrument two is installed on the bottom of the frame two, a control and data acquisition processing module two, a chip-level atomic clock one, a MEMS three-axis gyroscope two, an accelerometer two, a magnetometer and a power supply unit two are installed in the glass float ball group one; the frame two is installed on an anchor line, and an acoustic releaser one is installed between the frame two and the anchor line; The seabed base station comprises a frame three, a glass float ball group two is installed in the middle of the frame three, an acoustic Doppler current profiler two, a medium and low frequency navigation communication sonar three and a temperature-salinity-depth instrument three are installed on the top of the frame three, a control and data acquisition processing module three, a chip-level atomic clock two and a power supply unit three are installed in the glass float ball group two, the frame three is installed on a ballast anchor, and an acoustic releaser two is installed between the frame three and the ballast anchor; The shore base operation and control unit is composed of a two-way satellite communication terminal, a server and system operation and control software, and is configured to automatically receive base station network data returned by the buoy base station for a long time, including system working states of the base station network, and to perform two-way handshake interactive data communication and instruction issuing, and to issue relevant working mode switching instructions to the base station network, so as to realize remote control function.

2. An underwater navigation and communication integrated location service method using the underwater navigation and communication integrated location service system according to claim 1, characterized by, The system comprises base station laying, base station calibration, base station service and base station recovery, and specifically comprises the following steps: Step (1): before laying the subsurface buoy base station, the clock deviation of the chip-level atomic clock one of the subsurface buoy base station is calibrated by using GNSS timing, and the MEMS three-axis gyroscope two, the accelerometer two and the magnetometer of the subsurface buoy base station are calibrated; before laying the seabed base station, the clock deviation of the chip-level atomic clock two of the seabed base station is calibrated by using GNSS timing; after laying the subsurface buoy base station, the three-dimensional geodetic coordinates of the anchor point of the subsurface buoy base station are determined by using the acoustic releaser one multi-point positioning, and then the buoy base station and the seabed base station are laid; the subsurface buoy base station is laid at the depth closest to the sound channel axis in the base station network sea area; Step (2): after laying the base station network, the GNSS-acoustic combined positioning technology based on a surveying ship is adopted to measure the coordinate initial value of the acoustic center of the medium and low frequency navigation communication sonar two of the subsurface buoy base station and the coordinate initial value of the acoustic center of the medium and low frequency navigation communication sonar three of the seabed base station, and the coordinate initial values are input into the control and data acquisition processing module two and the control and data acquisition processing module three respectively; then the surveying ship returns or goes to other sea areas for operation; ​ Step (3): The base station network carries out long-term and continuous measurement according to the pre-set work plan and sampling frequency, and the shore-based operation and control unit sends instructions through satellite and underwater acoustic communication. The base station network receives and responds to the instructions of the shore-based operation and control unit, and switches the working mode according to the instructions, including switching the working / sleeping mode, the autonomous position service / shore-based operation and control position service mode, the sonar active ranging / passive ranging mode, the ocean temperature-salinity-depth flow observation data return mode, and the base station system state query mode; Step (4): After the service of the base station network is completed, the acoustic release one and the acoustic release two are released, so that the subsurface buoy base station and the seabed base station float to the sea surface, and the recovery of the buoy base station, the subsurface buoy base station and the seabed base station is carried out.

3. The underwater navigation and communication integrated location service method according to claim 2, wherein, During the autonomous position service mode of the base station network, autonomous real-time online base station position and clock calibration is carried out. The buoy base station obtains its instantaneous coordinates by real-time precise point positioning based on the Beidou-3 satellite precise point positioning service signal PPP-B2b and the Galileo satellite high-precision service signal HAS, and calibrates its sonar clock by GNSS timing. The subsurface buoy base station and the seabed base station calibrate chip-level atomic clock one and chip-level atomic clock two by underwater acoustic timing of the buoy base station, and periodically measure the underwater acoustic time delay between the subsurface buoy base station and the seabed base station and the buoy base station and carry out time synchronization. The subsurface buoy base station independently calculates the instantaneous coordinates of its sonar acoustic center by measuring the mutual underwater acoustic time delay between the subsurface buoy base station and the seabed base station and / or the buoy base station, the observation values of the temperature-salinity-depth instrument two and the MEMS three-axis gyroscope two, the accelerometer two and the magnetometer. Each base station broadcasts its position and clock to underwater users through underwater acoustic communication. The buoy base station constructs the prior sound speed field correction by using its own temperature-salinity-depth observation, the temperature-salinity-depth flow observation of each subsurface buoy base station and seabed base station, and the underwater acoustic time delay between the buoy base station and each subsurface buoy base station and seabed base station, and broadcasts it to underwater users and subsurface buoy base stations through underwater acoustic communication. The subsurface buoy base station broadcasts the prior sound speed field correction to underwater users through underwater acoustic communication. The underwater user corrects the prior sound speed field by using the underwater acoustic time delay measurement value of the navigation terminal and the base station network, and the received base station position, clock and prior sound speed field correction, and carries out positioning, navigation and timing.

4. The underwater navigation and communication integrated location service method according to claim 2, wherein, During the base station network switching to the shore-based operation and control position service mode, the base station position and clock calibration and the prior sound speed field construction are based on the shore-based operation and control unit; the base station water acoustic time delay and temperature-salinity-depth flow data measured by each of the subsurface buoy base stations and the seabed base stations are sent to the buoy base station through the acoustic water acoustic communication between the base stations, and together with the base station water acoustic time delay and temperature-salinity-depth data measured by the buoy base station, are sent to the shore-based operation and control unit through the satellite communication of the buoy base station for processing and calculation to obtain the base station position, clock and prior sound speed field correction, and then the shore-based operation and control unit sends the base station position, clock and sound speed field correction to the buoy base station through the satellite communication, and the buoy base station sends the base station position, clock and sound speed field correction to each of the subsurface buoy base stations and the seabed base stations through the acoustic water acoustic communication between the buoy base station and each of the subsurface buoy base stations and the seabed base stations, and each of the subsurface buoy base stations and the seabed base stations broadcasts the base station position, clock and prior sound speed field correction through the acoustic water acoustic communication for use by the underwater users.

5. The underwater navigation and communication integrated location service method according to claim 2, wherein, When the base station network switches to the acoustic active ranging mode according to the operation and control instructions, the underwater user navigation terminal and the base station network adopt the inquiry-response mode, that is, the underwater user navigation terminal sends an inquiry signal, and the base station network sends a response signal after receiving the inquiry signal; when the base station network switches to the acoustic passive ranging mode according to the operation and control instructions, the underwater user navigation terminal and the base station network adopt the synchronous mode, that is, the base station network synchronously broadcasts a ranging signal, and the underwater user navigation terminal receives the ranging signal; When the base station network switches to the ocean temperature-salinity-depth flow observation data return mode according to the operation and control instructions, according to the pre-setting, it is used for long-term and autonomous measurement of underwater acoustic positioning, navigation, timing and ocean environmental data, and is transmitted to the buoy base station through underwater acoustic communication, and then is transmitted to the shore-based operation and control unit receiving end through the satellite communication of the buoy base station; in addition, the base station network can increase the data return time interval from the hour level to the minute level or near real-time according to the operation and control instructions or the underwater user demand.

6. The underwater navigation and communication integrated location service method according to claim 5, wherein, The communication mode of the system is divided into two parts of satellite communication link and underwater acoustic communication link; the satellite communication link covers the shore-based operation and control unit to the buoy base station, the underwater acoustic communication link adopts the master-slave communication mode, and covers the buoy base station to the subsurface buoy base stations and the seabed base stations; in the acoustic communication process of the base station network and the shore-based operation and control unit and the underwater user terminal, data encryption and compression are performed.

7. The underwater navigation and communication integrated location service method according to claim 6, wherein, The satellite communication link adopts a bidirectional asynchronous communication mode, and transmits data based on the Beidou-3 point-to-point short message or the Tian Tong communication satellite; the satellite communication topology structure is that the buoy base station is the host, and the shore-based operation and control unit is the slave, and keeps the all-weather standby state; the satellite communication is divided into two working modes according to the demand, and the shore-based operation and control unit notifies the buoy base station to switch the two working modes by the way of issuing instructions: Mode 1: the satellite communication module of the buoy base station keeps the power-on state, and passively waits for the instruction sent by the shore-based operation and control unit, and feeds back the related instruction execution actions and feedback data according to the instruction; Mode 2: the satellite communication module of the buoy base station is closed and opened in a time manner, and starts to query the new command and return data sent by the shore-based operation and control unit in a time manner.

8. The underwater navigation and communication integrated location service method of claim 6, wherein, The underwater acoustic communication link adopts a bidirectional asynchronous communication mode for point-to-point data transmission of the sonar; the underwater acoustic communication topology is a star network operating in a master-slave mode, with the buoy base station as the central host node, the subsurface buoy base station and the seabed base station as peripheral slave nodes, and the peripheral slave nodes each connected to the central host node via an underwater acoustic communication channel; the central host node adopts a centralized communication control strategy, and the peripheral slave nodes cannot directly communicate with each other and must communicate via the central host node; in this mode, all peripheral slave nodes operate in a passive waiting mode, and the central host node initiates active handshaking and command issuance, and any peripheral slave node executes a command and feeds back a receipt after a two-way handshake, thus completing a communication process.

9. The underwater navigation and communication integrated location service method of claim 2, wherein, When the buoy base station cannot obtain the current observation of each subsurface buoy base station and seabed base station and the underwater acoustic time delay between the buoy base station and each subsurface buoy base station and seabed base station, the buoy base station only uses the temperature, salinity and depth observation of each subsurface buoy base station and seabed base station and itself to construct a prior sound speed field correction, and the specific method is as follows: First, the sound speed is calculated from the seawater temperature, salinity and pressure; Then, the sound velocity profile parameter C is fitted by using the following formula axis , ε, z axis , B: C(z) = C axis [1 + ε(η + e -η -1)] ; where z is the base thermosalinograph depth, C(z) is the computed sound speed value at depth z, C axis represents the sound speed at the channel axis, ∈ represents the sound speed perturbation coefficient, η represents the dimensionless distance, z axis is the channel axis depth, B is the channel scale thickness; Finally, the sound speed profile parameter C axis , ∈, z axis , B is broadcast to underwater users, which correct their prior sound speed field after receiving.

10. The underwater navigation and communication integrated location service method of claim 2, wherein, The subsurface buoy base station adopts a single-point taut anchor system for anchoring the entire subsurface buoy base station and recovering it in its entirety after service completion; when the subsurface buoy base station cannot measure the underwater acoustic time delay with the buoy base station and the seabed base station, the subsurface buoy base station performs independent real-time online position self-calibration, and the specific method is as follows: First, the pitch angle, roll angle and azimuth angle are calculated from the observation values of the second accelerometer and the magnetometer, respectively; Then, the real-time position of the buoy base station is calculated by the following formula: In the formula, E, N and U are the east, north and elevation direction coordinates of the second medium-low frequency navigation communication sonar of the subsurface buoy base station relative to the anchor point, L is the cable length from the second medium-low frequency navigation communication sonar of the subsurface buoy base station to the anchor point, and α, β and γ are the pitch angle, roll angle and azimuth angle of the subsurface buoy base station, respectively. Finally, the three-dimensional geodetic coordinates of the second medium-low frequency navigation communication sonar of the subsurface buoy base station are calculated from the three-dimensional geodetic coordinates of the anchor point and E, N and U.

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