Device and method for autonomous exploration of underwater small target

Abstract

The invention relates to an autonomous exploration device and method for underwater small targets, and the device comprises an electronic energy module which is used for supplying energy to other modules in the device, and carrying out the power supply management. The autonomous control module is used for completing autonomous probing and side scanning of a specified detection area according to a set detection task, autonomously planning and confirming a probing path according to a target recognition result, completing probing and confirming of the target, storing image information and coordinate information of the underwater small target, and sending the image information and coordinate information to the server; and the position information of the small target is uploaded through the wireless transmission module. According to the invention, autonomous exploration and target confirmation of small targets in a large-range area can be realized.

Description

Technical field:

[0001] The present invention belongs to the technical field of underwater target detection, and in particular relates to a device and method for autonomously detecting small underwater targets. Background technology:

[0002] Small underwater targets such as mines and underwater pre-placed buoys play a very important role in underwater offensive and defensive operations due to their small size and strong concealment. Therefore, it is of practical significance to develop a portable device and method for autonomous detection of small underwater targets.

[0003] There are two existing means of detecting small underwater targets: acoustic and optical. Acoustic detection is usually based on side-scan sonar mounted on surface ships, which can perform large-scale underwater side-scanning imaging and imaging detection of large targets such as shipwrecks, but has problems with low imaging resolution and high false alarm rate for small targets. By mounting side-scan sonar and synthetic aperture sonar on underwater unmanned vehicles, effective close-in reconnaissance of small underwater targets can be carried out, with high positioning accuracy, but the acoustic imaging resolution is low, and small underwater targets cannot be effectively confirmed. The false alarm rate is high, and optical confirmation is usually required to assist. Optical detection is usually based on ROV sailing underwater to perform side-scanning operations. Acoustic + optical imaging can intuitively and reliably identify small underwater targets, but the visible distance is short, and due to the limitations of the umbilical cable, large-scale detection operations cannot be carried out, and the operation efficiency is low. Summary of the invention:

[0004] The technical problem to be solved by the present invention is to provide a device and method for autonomous detection of small underwater targets. The device is based on side-scan sonar, underwater lighting imaging and underwater combined navigation and positioning to achieve autonomous detection and target confirmation of small and medium-sized targets in a large area.

[0005] The technical solution of the present invention is to provide a device for autonomous detection of small underwater targets, including

[0006] Electronic energy module, which is used to supply energy to other modules in the device and perform power supply management;

[0007] Autonomous control module, which is used to complete autonomous exploration and scanning of the designated detection area according to the set detection task, and autonomously plan and confirm the detection path according to the target recognition result, complete the detection and confirmation of the target, save the image information and coordinate information of the underwater small target, and upload the location information of the small target through the wireless transmission module;

[0008] The power module is used to receive the motion control instructions output by the autonomous control module and control the motion posture of the AUV during the autonomous exploration and scanning process;

[0009] Small target detection module, which is used to perform underwater small target detection and confirmation tasks, and includes side-scan sonar and underwater lighting imaging device;

[0010] Integrated navigation and positioning module, used to provide the AUV’s own geographic location information;

[0011] Wireless transmission module, the wireless transmission module includes surface wireless transmission and underwater hydroacoustic communication. Surface wireless transmission uses radio stations and WIFI to realize short-distance and medium-short-distance information transmission respectively, and underwater hydroacoustic communication realizes data communication between the AUV and the surface shore during the underwater detection mission.

[0012] The present invention inversely infers the noise source of sonar background noise based on measured data. Since the measured data is information generated by the common superposition of multiple noise sources, the noise source includes all information sources of mechanical noise, hydrodynamic noise, and propeller noise in the sonar background noise. By inputting the inverted noise source conditions, the comprehensive sonar background noise including mechanical noise, hydrodynamic noise, and propeller noise can be simulated and calculated to achieve a comprehensive and accurate prediction of the sonar background noise, providing a technical basis for a comprehensive suppression scheme of the sonar background noise.

[0013] Preferably, the power module includes a propulsion motor and four direction control steering gears. The propulsion motor controls the speed through CAN communication to enable the AUV to sail at different speeds in the water. The rudder angles of the four steering gears, upper, lower, left and right, are controlled through CAN. Controlling the angles of the left and right steering gears can realize the AUV's floating and diving maneuvers, and controlling the angles of the upper and lower steering gears can realize the AUV's left and right turning maneuvers. In this way, the power control of the AUV is realized.

[0014] Preferably, the electronic energy module adopts a ternary lithium battery pack to supply energy to other modules in the device and perform power supply management; and converts the voltage into 5V, 12V, 24V and 48V power supply voltages through the power supply management board, of which 5V is used to supply the autonomous control module and the servo of the power module, 12V supplies the combined navigation and positioning module and the wireless transmission module, 24V independently supplies the small target detection module, and 48V supplies the propulsion motor in the power module.

[0015] Preferably, the power supply management board also has a power supply management function, which can power on and off the small target detection module.

[0016] As a preferred embodiment, the autonomous control module includes a Loongson 2K1000 control board, which is connected to the switch through the network port, and the switch is connected to WIFI, side-scan sonar ES900U, and underwater lighting imaging equipment through the network; the Loongson 2K1000 control board is connected to the radio station and underwater acoustic communication machine through the RS232 serial port to realize data transmission with the ship-borne shore base; the radio station, Beidou and WIFI are connected to the integrated antenna outside the cabin through the signal transceiver circuit; the Loongson 2K1000 control board is connected to the RS232 serial port through the RS232 serial port. The RS232 serial port is used to connect with the lithium battery pack and power management board related devices to analyze the equipment data and manage the energy status of the AUV. The Loongson 2K1000 control board is connected with Beidou, IMU, DVL, and depth meter through the RS232 serial port to analyze the collected data and perform combined navigation to realize the positioning of the AUV. The Loongson 2K1000 control board realizes the motion control of the propulsion motor through CAN1 and the simultaneous control of the four-way servos through CAN2 to complete the motion control of the AUV.

[0017] Preferably, the small target detection module realizes large-scale side scanning and preliminary exploration and positioning of underwater small targets through side-scan sonar, and realizes confirmation of underwater small targets through underwater lighting and imaging device, thereby realizing accurate positioning and identification of underwater small targets while ensuring large-scale side scanning.

[0018] Preferably, the underwater lighting and imaging device includes a searchlight and a camera. The searchlight is installed at the head to illuminate downward, and the camera is installed at the tail to observe forward and downward. The spacing distance is greater than 1.5m to reduce the impact of underwater light backscattering.

[0019] Preferably, the combined navigation and positioning module includes IMU, DVL, depth meter, and at least one of Beidou and GPS, wherein surface navigation and positioning use Beidou or GPS, and underwater combined navigation and positioning use IMU, DVL, depth meter.

[0020] The present invention also provides an automatic detection method based on the above-mentioned device for autonomous detection of underwater small targets, comprising the following steps:

[0021] Step 1: After the autonomous exploration device starts running, the AUV autonomous control module performs autonomous side scanning operations on the designated area according to the set tasks, and the AUV power module drives the AUV to navigate along the set trajectory according to the motion control instructions;

[0022] Step 2: When the AUV is navigating along the set track, the side scan sonar in the small target detection module is turned on to perform side scan imaging of the designated detection area. When a suspected small target is captured and identified in the detection area, its position is calculated and saved in the suspected target queue;

[0023] Step 3: After the autonomous exploration device completes the autonomous side scanning task of the designated area, the AUV autonomous control module plans a square fine detection path centered on each target according to the order of distance in the suspected target queue. The autonomous exploration device re-explores the target according to the fine detection path to form a possible target queue;

[0024] Step 4: The autonomous exploration device turns off the side-scan sonar in the small target detection module, turns on the lighting imaging device, and conducts precise exploration of the targets in the possible target queue according to the distance. The AUV autonomous control module controls the AUV to pass over the target, optically image the target, and finally confirm the target, and transmits the coordinates and category back to the shore base on the water surface through the hydroacoustic communication in the wireless transmission module;

[0025] Step 5: After completing the detection mission, turn off the underwater lighting and imaging device, and the autonomous exploration device will perform the return mission according to the set return point to end the operation.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. A method for autonomous detection of small underwater targets can autonomously detect and confirm small targets underwater, transmit the coordinates and category information of small targets back to the shore base on the surface, and can autonomously perform large-scale side scanning without human intervention, effectively improving the work efficiency and detection accuracy of small underwater targets.

[0028] 2. The use of a combined acoustic and optical detection method can improve the accuracy of small target positioning and identification in complex marine environments. The side-scan sonar detection image can initially identify and locate the coordinates of small targets, and the lighting imaging device can confirm the category information of underwater small targets, which can effectively improve the accuracy of underwater detection. Description of the drawings:

[0029] Figure 1 It is a schematic diagram of a portable device for autonomous detection of small underwater targets in an embodiment.

[0030] Figure 2 It is a structural diagram of a portable device for autonomous detection of small underwater targets in an embodiment.

[0031] Figure 3 Schematic diagram of the electronic energy module in the embodiment.

[0032] Figure 4 Schematic diagram of a power module in an embodiment.

[0033] Figure 5 Schematic diagram of the combined navigation module in the embodiment.

[0034] Figure 6 Schematic diagram of a small target detection module in an embodiment.

[0035] Figure 7 Schematic diagram of a wireless transmission module in an embodiment.

[0036] Figure 8 It is a flow chart of the method for autonomous detection of underwater small targets in an embodiment.

[0037] Fig. 9 Schematic diagram of the trajectory of the underwater small target autonomous detection method in the embodiment.

[0038] Fig.10 It is an example of a small target detected by the side-scan sonar when the underwater small target autonomous detection device in the embodiment performs detection task 0.

[0039] Fig.11 It is an example of a small target detected by the side scan sonar when the underwater small target autonomous detection device in the embodiment performs detection task 1.

[0040] Fig.12 It is an example of a small target detected by illumination imaging when the underwater small target autonomous detection device in the embodiment performs detection task 2. Specific implementation method:

[0041] The present invention will be further described below with reference to the accompanying drawings:

[0042] like Figure 1 As shown, a portable device for autonomous detection of underwater small targets includes an electronic energy module, an autonomous control module, a power module, a small target detection module, a combined navigation and positioning module, and a wireless transmission module. Its appearance and structure are as follows Figure 2 As shown; among them,

[0043] The electronic energy module is used to supply energy to other modules in the device and manage the power supply. Figure 3 As shown, the module includes: a charging port, a charging circuit, a lithium battery pack, a power switch, a switch circuit, and a power management board. The lithium battery pack shown is a ternary lithium battery pack, which provides 23V to 32V DC power. The voltage is converted through the power management board to 5V, 12V, 24V and 48V power supply voltages, of which 5V is used to supply the autonomous control module and the servo of the power module, 12V is shared with the combined navigation and positioning module and the wireless transmission module, 24V is independently shared with the small target detection module, and 48V is supplied to the propulsion motor in the power module. The power management board also has a power supply management function, which can power on and off the small target detection module to save functional loss during the AUV mission.

[0044] The power module 4 receives the motion control instructions output by the autonomous control module to control the motion posture of the AUV during the autonomous exploration and scanning process. Figure 4As shown in the figure, the AUV power module includes a propulsion motor and four direction control servos. The propulsion motor controls the speed through CAN communication to enable the AUV to sail at different speeds in the water. The rudder angles of the four servos, upper, lower, left and right, are controlled through CAN. Controlling the angles of the left and right servos can realize the AUV's surfacing and diving maneuvers, and controlling the angles of the upper and lower servos can realize the AUV's left and right turning maneuvers. This is how the AUV's power control is achieved.

[0045] Integrated navigation and positioning module 6 Figure 5 As shown, it includes Beidou, IMU, DVL, and depth meter. Beidou is used for surface navigation and positioning, and IMU, DVL, and depth meter are used for underwater combined navigation and positioning to provide the AUV's own geographic location information.

[0046] The small target detection module includes a side-scan sonar 1 and an underwater lighting imaging device. In this embodiment, the underwater lighting imaging device includes a lighting lamp 2 and a camera 3. Figure 6 As shown in the figure, the underwater small target detection and confirmation task is performed. The side scan sonar is used to achieve large-scale side scanning and preliminary detection and positioning of underwater small targets, and the underwater lighting imaging device is used to confirm the underwater small targets. While ensuring large-scale side scanning, the underwater small targets can be accurately positioned and identified, greatly improving the detection efficiency of underwater small targets.

[0047] The wireless transmission module 5 includes surface wireless transmission and underwater hydroacoustic communication, such as Figure 7 As shown. Surface wireless transmission uses radio stations and WIFI to achieve short-range and medium-short-range information transmission respectively, which are used for detection tasks, the issuance of control instructions and the transmission of detection data. Underwater hydroacoustic communication is based on the hydroacoustic communicator to realize data communication between the AUV and the surface shore during the underwater detection mission, and can send back the coordinate information of small underwater targets in real time. The radio station, WIFI and hydroacoustic communicator must be paired and installed on the ship-borne shore platform to realize data transmission between the AUV and the ship-borne shore platform.

[0048] The autonomous control module completes the autonomous exploration and scanning of the designated detection area according to the set detection task, and autonomously plans and confirms the exploration path according to the target recognition result, completes the detection and confirmation of the target, saves the image information and coordinate information of the underwater small target, and uploads the location information of the small target through the wireless transmission module. Figure 8As shown, the autonomous control module mainly includes a Loongson 2K1000 control board. The Loongson 2K1000 control board is connected to the switch through the network port, and the switch is connected to WIFI, side-scan sonar ES900U, and underwater lighting imaging equipment through the network; the Loongson 2K1000 control board is connected to the radio station and underwater acoustic communication machine through the RS232 serial port to realize data transmission with the ship-borne shore base; the radio station, Beidou and WIFI are connected to the integrated antenna outside the cabin through the signal transceiver circuit; the Loongson 2K1000 control board is connected to the lithium battery pack, power supply management board and other devices through the RS232 serial port to realize equipment data analysis and manage the energy status of the AUV; the Loongson 2K1000 control board is connected to Beidou, IMU, DVL, and depth gauge through the RS232 serial port to analyze the collected data and perform combined navigation to realize the positioning of the AUV; the Loongson 2K1000 control board realizes the motion control of the propulsion motor through CAN1 and the simultaneous control of the four-way steering gear through CAN2 to complete the motion control of the AUV.

[0049] like Fig. 9 As shown, a method for autonomously detecting small underwater targets uses the above-mentioned device to detect and scan small underwater targets, which specifically includes the following steps:

[0050] Step 1: After the autonomous exploration device starts running, the AUV autonomous control module performs autonomous side scanning operations on the designated area according to the set tasks, and the AUV power module drives the AUV to navigate along the set trajectory according to the motion control instructions, such as Fig. 9 Probe task 0 is shown.

[0051] Step 2: When the AUV is navigating along the set track, the side scan sonar in the small target detection module is turned on to perform side scan imaging of the specified detection area. The small targets in the real-time output side scan image are identified through the trained YOLO-V3-tiny small target recognition inference model. When a suspected small target is captured and identified in the detection area, its position is solved and saved in the suspected target queue. The detection and recognition example results are shown in the figure below. Fig.10 shown.

[0052] Step 3: After the autonomous exploration device completes the autonomous side scanning task of the designated area, the AUV autonomous control module plans a square fine detection path centered on each target according to the order of distance in the suspected target queue, such as Fig. 9 In the detection task 1 shown in the figure, the autonomous detection device realizes the re-exploration of the target according to the refined detection path, and recognizes the small targets in the real-time output side scan image through the trained YOLO-V3-tiny small target recognition inference model to form a possible target queue. The detection and recognition result is shown in the figure below. Fig.11 shown.

[0053] Step 4: The autonomous exploration device turns off the side-scan sonar in the small target detection module, turns on the underwater lighting imaging device, and conducts precise exploration of the targets in the possible target queue according to their distance, and plans an overhead detection path for each target, such as Fig. 9 In the detection task 2 shown in the figure, the AUV autonomous control module controls the AUV to pass over the target, performs optical imaging of the target, and uses the trained YOLO-V3-tiny small target recognition inference model to recognize the small target in the real-time output optical image, and finally confirms the target. The detection and recognition result example is shown in Fig.12 As shown, the coordinates and categories are transmitted back to the surface shore base through the hydroacoustic communication in the wireless transmission module.

[0054] Step 5: After completing the detection mission, turn off the underwater lighting and imaging device, and the autonomous exploration device will perform the return mission according to the set return point to end the operation.

[0055] It can be seen that the present invention adopts an autonomous detection method for underwater small targets by combining sound and light detection. The side-scan sonar detection image is used to preliminarily identify and locate the coordinates of small targets. Based on the combined navigation device and the underwater autonomous AUV platform, accurate detection of small targets is achieved. The lighting imaging device is used to confirm the category information of underwater small targets, which can effectively improve the accuracy of underwater detection.

[0056] The above is only an explanation of the preferred embodiments of the present invention, which should not be construed as a limitation on the claims. Any equivalent process changes made using the present invention specification are included in the patent protection scope of the present invention.

Claims

1. A device for autonomous detection of small underwater targets, characterized in that: include Electronic energy module, which is used to supply energy to other modules in the device and perform power supply management; Autonomous control module, which is used to complete autonomous exploration and scanning of the designated detection area according to the set detection task, and autonomously plan and confirm the detection path according to the target recognition result, complete the detection and confirmation of the target, save the image information and coordinate information of the underwater small target, and upload the location information of the small target through the wireless transmission module; The power module is used to receive the motion control instructions output by the autonomous control module and control the motion posture of the AUV during the autonomous exploration and scanning process; Small target detection module, which is used to perform underwater small target detection and confirmation tasks, and includes side-scan sonar and underwater lighting imaging device; Integrated navigation and positioning module, used to provide the AUV’s own geographic location information; Wireless transmission module, the wireless transmission module includes surface wireless transmission and underwater hydroacoustic communication. Surface wireless transmission is used to realize short-distance and medium-short-distance information transmission, and underwater hydroacoustic communication is used to realize data communication between the AUV and the surface shore during the underwater detection mission.

2. The device for autonomous detection of underwater small targets according to claim 1, characterized in that: The power module includes a propulsion motor and four direction control servos. The propulsion motor controls the speed through CAN communication to enable the AUV to sail at different speeds in the water. The rudder angles of the four servos, up, down, left, and right, are controlled through CAN. Controlling the angles of the left and right servos can enable the AUV to float up and dive down, and controlling the angles of the upper and lower servos can enable the AUV to turn left and right. This is how the power control of the AUV is achieved.

3. The device for autonomous detection of underwater small targets according to claim 2, characterized in that: The electronic energy module uses a ternary lithium battery pack to supply energy to other modules in the device and perform power supply management; and converts the voltage into 5V, 12V, 24V and 48V power supply voltages through the power supply management board, of which 5V is used to supply the autonomous control module and the servos of the power module, 12V supplies the combined navigation and positioning module and the wireless transmission module, 24V independently supplies the small target detection module, and 48V supplies the propulsion motor in the power module.

4. The device for autonomous detection of underwater small targets according to claim 3, characterized in that: The power management board also has the power management function, which can power on and off the small target detection module.

5. The device for autonomous detection of underwater small targets according to claim 3, characterized in that: The autonomous control module includes a Loongson 2K1000 control board. The Loongson 2K1000 control board is connected to the switch through the network port, and the switch is connected to WIFI, side-scan sonar ES900U, and underwater lighting imaging equipment through the network; the Loongson 2K1000 control board is connected to the radio station and underwater acoustic communication machine through the RS232 serial port to realize data transmission with the ship-borne shore base; the radio station, Beidou and WIFI are connected to the integrated antenna outside the cabin through the signal transceiver circuit; the Loongson 2K1000 control board is connected to the lithium battery pack and the power supply management board related devices through the RS232 serial port to realize equipment data analysis and manage the AUV energy status; the Loongson 2K1000 control board is connected to Beidou, IMU, DVL, and depth gauge through the RS232 serial port to analyze the collected data and perform combined navigation to realize the positioning of the AUV; the Loongson 2K1000 control board realizes the motion control of the propulsion motor through CAN1 and the simultaneous control of the four-way steering gear through CAN2 to complete the motion control of the AUV.

6. The device for autonomous detection of underwater small targets according to claim 1, characterized in that: The small target detection module uses side-scan sonar to achieve large-scale side scanning and preliminary exploration and positioning of small underwater targets, and confirms small underwater targets through underwater lighting and imaging devices, thereby ensuring large-scale side scanning while achieving precise positioning and identification of small underwater targets.

7. The device for autonomous detection of underwater small targets according to claim 6, characterized in that: The underwater lighting and imaging device includes a searchlight and a camera. The searchlight is installed at the head and irradiates downward, and the camera is installed at the tail and observes forward and downward. The distance between them is greater than 1.5m to reduce the impact of underwater light backscattering.

8. The device for autonomous detection of underwater small targets according to claim 1, characterized in that: The integrated navigation and positioning module includes IMU, DVL, depth meter, and at least one of Beidou and GPS, wherein surface navigation and positioning use Beidou or GPS, and underwater integrated navigation and positioning use IMU, DVL, depth meter.

9. A method based on the device for autonomous detection of underwater small targets according to any one of claims 1 to 8, characterized in that: The following steps are included: Step 1: After the autonomous exploration device starts running, the AUV autonomous control module performs autonomous side scanning operations on the designated area according to the set tasks, and the AUV power module drives the AUV to navigate along the set trajectory according to the motion control instructions; Step 2: When the AUV is navigating along the set track, the side scan sonar in the small target detection module is turned on to perform side scan imaging of the designated detection area. When a suspected small target is captured and identified in the detection area, its position is calculated and saved in the suspected target queue; Step 3: After the autonomous exploration device completes the autonomous side scanning task of the designated area, the AUV autonomous control module plans a square fine detection path centered on each target according to the order of distance in the suspected target queue. The autonomous exploration device re-explores the target according to the fine detection path to form a possible target queue; Step 4: The autonomous exploration device turns off the side-scan sonar in the small target detection module, turns on the lighting imaging device, and conducts precise exploration of the targets in the possible target queue according to the distance. The AUV autonomous control module controls the AUV to pass over the target, optically image the target, and finally confirm the target, and transmits the coordinates and category back to the shore base on the water surface through the hydroacoustic communication in the wireless transmission module; Step 5: After completing the detection mission, turn off the underwater lighting and imaging device, and the autonomous exploration device will perform the return mission according to the set return point to end the operation.

Images