Full-coverage sonar detection equipment and implementation method thereof

Abstract

The invention discloses full-coverage sonar detection equipment and an implementation method thereof.The equipment comprises a dragging body, a side-scan sonar system and a gap sonar system, the side-scan sonar system comprises two side-scan transducer arrays, the two side-scan transducer arrays are arranged on the two sides of the middle of the dragging body respectively, and the gap sonar system is arranged between the two side-scan transducer arrays; the slit sonar system comprises a foresight transmitting transducer array and a foresight receiving transducer array, the slit sonar system is arranged below the front end portion of the dragging body, and the foresight transmitting transducer array and the foresight receiving transducer array are both installed below the front end portion of the dragging body in an obliquely downward mode. According to the invention, the slit sonar system is arranged below the front end part of the dragging body, and the foresight transmitting transducer array and the foresight receiving transducer array of the slit sonar system are obliquely and downwards arranged below the front end part of the dragging body, so that the detection of a detection area below the advancing direction of the dragging body is realized; the problem that a side-scan sonar system cannot scan a detection blind area is solved, and the detection coverage area of detection equipment is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sonar signal processing, and in particular to a full-coverage sonar detection device and an implementation method thereof. Background Art

[0002] A sidescan sonar system is an underwater acoustic device that uses the principle of echo sounding to detect the seabed topography and underwater objects, and is widely used in marine surveying and mapping, marine geological surveys, marine engineering exploration, seabed target detection such as detecting sunken ships, torpedoes and mines, port construction, and channel dredging.

[0003] As Figure 1 shown, the sidescan sonar system uses the towing method for measurement. During operation, the transducer arrays on both sides of the towing body first emit electrical pulses of a certain frequency, which are then converted into acoustic pulses and transmitted to the seabed on both sides. When the sound waves propagate in the seabed or underwater objects, they will be reflected and return along the original propagation route. The transducer converts the received echo signals into a series of electrical pulses, which are then processed and displayed as a horizontal line on the display. Each echo data is converted into a horizontal line, and after being arranged in order, an acoustic image reflecting the seabed topography is formed.

[0004] As Figures 1 to 3 shown, the sidescan transducer arrays of the sidescan sonar system are installed on both sides of the towing body. The sidescan transducer arrays have a certain inclination angle with the horizontal plane. At the same time, due to the limited emission opening angle of the sidescan transducer arrays, the sidescan sonar system mainly detects the seabed topography on both sides of the navigation direction during detection. The black area directly below is the detection blind area. Suppose the angle J1 between the sidescan transducer array and the horizontal plane is 25°, and the emission opening angle Jv of the sidescan transducer array is 45°. Then the detection blind area angle θm directly below one-sided sidescan transducer array is θm = 90° - J1 – Jv / 2 = 42.5°, and the total detection blind area angle directly below the two sidescan transducer arrays is 2θm = 85°; where the detection blind area angle directly below one-sided sidescan transducer array is the angle between the detection edge plane of the one-sided sidescan transducer array and the plane perpendicular to the horizontal plane and consistent with the forward direction of the towing body.

[0005] When using the sidescan sonar system for fine measurement of the seabed topography or detecting seabed targets, 100% full-coverage of the detection area is required. The traditional detection method uses the cross-cross measurement method to meet the basic requirements of full coverage. This method has low detection efficiency, large workload, time-consuming and laborious, especially in the field of underwater search and rescue.

[0006] Therefore, there is an urgent need to propose a full-coverage sonar detection device and an implementation method thereof to solve the problems raised. Summary of the Invention

[0007] Based on this, the object of the present invention is to provide an all-round coverage sonar detection device and its implementation method, which can solve the problem of detection blind areas existing in side-scan sonar systems and improve the detection coverage area of the detection device.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0009] In the first aspect, an all-round coverage sonar detection device is provided, which includes a towing body and a side-scan sonar system. The side-scan sonar system includes two side-scan transducer arrays, and the two side-scan transducer arrays are respectively arranged on both sides of the middle part of the towing body. It also includes a seam-filling sonar system, and the seam-filling sonar system includes a forward-looking transmitting transducer array and a forward-looking receiving transducer array. The seam-filling sonar system is placed below the front end of the towing body, and both the forward-looking transmitting transducer array and the forward-looking receiving transducer array are obliquely installed downward below the front end of the towing body.

[0010] Further, the installation height of the seam-filling sonar system and the side-scan sonar system on the towing body is the same.

[0011] Further, an altimeter is also arranged at the bottom end of the towing body. The altimeter is installed below the rear end of the towing body and is used to measure the height of the towing body from the seabed ground.

[0012] Further, a housing is arranged at the front end of the towing body. Both the forward-looking transmitting transducer array and the forward-looking receiving transducer array of the seam-filling sonar system are placed in this housing. The beam opening angle of the forward-looking transmitting transducer array and the forward-looking receiving transducer array in a plane perpendicular to the traveling direction of the towing body is β, and the beam opening angle of the forward-looking transmitting transducer array and the forward-looking receiving transducer array in a plane coinciding with the traveling direction of the towing body is θ; β≥2θm, where θm is the detection blind area angle directly below the unilateral side-scan transducer array.

[0013] Further, the forward-looking transmitting transducer array is distributed in an arc in the housing, and the forward-looking receiving transducer array is distributed in a straight line in the housing.

[0014] Further, it also includes a hull, and the hull is connected to the towing body through a towing system.

[0015] In the second aspect, an implementation method of an all-round coverage sonar detection device is provided, which includes the following steps:

[0016] S1. Select a sampling straight line l1 corresponding to the beam center area of the seam-filling sonar system;

[0017] S2. Select a sampling starting point S1 of the detection image of the seam-filling sonar system; the sampling starting point S2 is located at the intersection of this sampling straight line l2 and the seabed ground;

[0018] S3. Obtain the detection image of the seam-filling sonar system;

[0019] S4, selecting a sampling line l2 corresponding to a central area of ​​a side scan transducer beam of a side scan transducer array in a side scan sonar system; the side scan transducer array is composed of a plurality of side scan transducers arranged along the length direction of the towed body;

[0020] S5, selecting the sampling starting point S2 of the detection image corresponding to the side scan transducer; the sampling starting point S2 is located at the intersection of the sampling straight line l2 and the seabed surface;

[0021] S6, acquiring a detection image of a side-scan sonar system;

[0022] S7, obtaining the distance d between the sampling starting point S1 and the sampling starting point S2 along the length direction of the dragging body;

[0023] S8. In the detection image of the gap-filling sonar system, capture the detection image after the preset time t of sampling start of the gap-filling sonar system, and then piece it together with the detection image of the side-scan sonar system to form a detection image of the full-coverage sonar detection equipment; the sampling start time of the visual sonar system is no later than the sampling start time of the side-scan sonar system, and the sampling start time of the visual sonar system differs from the sampling start time of the side-scan sonar system by a time length of t2, t=t1+t2=d / V+t2, t1=d / V, V is the moving speed of the towed body.

[0024] Furthermore, in step S8, when t2=0, the sampling start time of the gap-filling sonar system is consistent with the sampling start time of the side-scan sonar system, t=t1=d / V.

[0025] Furthermore, the method of obtaining the detection image of the crack-filling sonar system in step S3 is specifically performed as follows:

[0026] The acquisition length of the preset gap filling sonar system along the traveling direction of the towed body in each working cycle T is ΔD, and the acquisition length ΔD is not greater than H*tanα-H*tan(α-θ / 2); wherein H is the height of the towed body from the seabed, θ is the beam opening angle of the forward-looking receiving transducer array on the plane coinciding with the traveling direction of the towed body, and α is the angle between the forward-looking receiving transducer array and the plane perpendicular to the traveling direction of the towed body;

[0027] As the full-coverage sonar detection equipment moves, the sampling starting point S1 also moves synchronously, and the lateral strip area corresponding to the sampling starting point S1 also moves synchronously, thereby forming a detection image of the gap-filling sonar system; wherein, the working cycle T of the gap-filling sonar system satisfies: VT=ΔD.

[0028] Furthermore, the acquisition length ΔD=H*tanα-H*tan(α-θ / 2).

[0029] In summary, for the all - coverage sonar detection device and its implementation method of the present invention, by arranging a gap - filling sonar system below the front end of the towing body, and cooperating with obliquely downward installation of both the forward - looking transmitting transducer array and the forward - looking receiving transducer array of the gap - filling sonar system below the front end of the towing body, the detection of the detection area below the traveling direction of the towing body is realized, so as to make up for the problem that the side - scan sonar system cannot scan the detection blind area, and further improve the detection coverage area of the detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of the detection scenario of an existing side - scan sonar system;

[0031] Figure 2 is a schematic diagram of the detection angle of an existing side - scan sonar system;

[0032] Figure 3 is a schematic diagram of the detection blind area of an existing side - scan sonar system;

[0033] Figure 4 is a schematic diagram of the structure of the all - coverage sonar detection device provided by an embodiment of the present invention;

[0034] Figure 5 is a schematic diagram of the structure of the forward - looking transmitting transducer array and the forward - looking receiving transducer array in the gap - filling sonar system provided by an embodiment of the present invention;

[0035] Figure 6 is a schematic diagram of the structure of the all - coverage sonar detection device with the hull hidden provided by an embodiment of the present invention;

[0036] Figure 7 is a circuit structure block diagram corresponding to the gap - filling sonar system provided by an embodiment of the present invention;

[0037] Figure 8 is a schematic diagram of the principle of selecting the acquisition length of the gap - filling sonar system along the traveling direction of the towing body. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] In order to further understand the features, technical means, and specific purposes and functions achieved by the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0039] Figure 4 shows a schematic diagram of an all - coverage sonar detection device to which the implementation method of an all - coverage sonar detection device is applicable. The all - coverage sonar detection device includes a towing body and a side - scan sonar system. The side - scan sonar system includes two side - scan transducer arrays, and the two side - scan transducer arrays are respectively arranged on both sides of the middle part of the towing body.

[0040] Since the side-scan sonar transducer array of the side-scan sonar system is installed on both sides of the towed body, the side-scan sonar transducer array has a certain inclination angle with the horizontal plane. At the same time, due to the limited emission opening angle of the side-scan sonar transducer array, the side-scan sonar system mainly detects the seabed topography on both sides of the navigation direction during detection, and there will be a detection blind area directly below the forward direction of the towed body; the width of this detection blind area changes with the height of the towed body from the seabed, and the edge surface angle corresponding to this detection blind area is the same as the detection blind area angle directly below the single-side side-scan sonar transducer array, that is, the edge surface angle θm corresponding to this detection blind area = 90° - J1 – Jv / 2, where J1 is the angle between the side-scan sonar transducer array and the horizontal plane, and Jv is the emission opening angle of the side-scan sonar transducer array, as Figure 2 shown.

[0041] As Figure 6 shown, to solve the problem that there is a detection blind area directly below the forward direction of the side-scan sonar system on the towed body, the full-coverage sonar detection device of the present invention further includes a seam sonar system. The seam sonar system adopts the structure of a forward-looking sonar system. The seam sonar system includes a forward-looking transmitting transducer array and a forward-looking receiving transducer array, and the seam sonar system is placed at the front end of the towed body; the seam sonar system is used to detect the detection area below the forward direction of the towed body, and the width of this below detection area should not be less than the width of the detection blind area to make up for the problem that the side-scan sonar system cannot scan the detection blind area.

[0042] The forward-looking transmitting transducer array of the existing forward-looking sonar system is used to generate a fan-shaped acoustic wave beam with a certain beam angle to irradiate a narrow water area directly in front of the survey ship. The forward-looking receiving transducer array of the existing forward-looking sonar system is used to receive the echo signal generated by the acoustic wave beam emitted by the forward-looking transmitting transducer array, and then detect the obstacles in front of the towed body; to achieve the effect of detecting the obstacles in front of the towed body, the forward-looking transmitting transducer array and the forward-looking receiving transducer array of the existing forward-looking sonar system are installed in the middle of the front end of the towed body, and the installation direction of the forward-looking receiving transducer array is the same as the forward direction of the towed body to receive as many echo signals generated by the acoustic wave beam emitted by the forward-looking transmitting transducer array as possible. The forward-looking transmitting transducer array and the forward-looking receiving transducer array of the existing forward-looking sonar system are both installed horizontally in the middle of the front end of the towed body, so as to meet the effect of detecting the obstacles in front of the towed body.

[0043] To avoid the problem that the seam sonar system of the present invention can only detect the obstacles in front of the towed body and cannot make up for the problem that the side-scan sonar system cannot scan the detection blind area, the full-coverage sonar detection device of the present invention is implemented in the following way.

[0044] The gap-filling sonar system of the present invention is placed below the front end of the towed body. The forward-looking transmitting transducer array and the forward-looking receiving transducer array of the gap-filling sonar system are both installed obliquely downward below the front end of the towed body. Specifically, the forward-looking transmitting transducer array and the forward-looking receiving transducer array of the gap-filling sonar system are arranged at an angle α with the plane perpendicular to the traveling direction of the towed body. Therefore, in addition to having the effect of detecting obstacles in front like a traditional forward-looking sonar system, the gap-filling sonar system of the present invention can also detect the detection area below the traveling direction of the towed body to make up for the problem that the side-scan sonar system cannot scan the detection blind area, thereby improving the detection coverage area of the full-coverage sonar detection device of the present invention; in this embodiment, α = 30°.

[0045] In one embodiment, the gap-filling sonar system and the side-scan sonar system are installed at the same height on the towed body to more conveniently and accurately splice the imaging data obtained by the gap-filling sonar system and the imaging data obtained by the side-scan sonar system in the later stage to achieve the detection effect without blind areas.

[0046] In one embodiment, an altimeter is further provided at the bottom end of the towed body. On the towed body, the altimeter is installed at a position different from that of the gap-filling sonar system and the side-scan sonar system to avoid the problem of mutual interference between the signals of the altimeter and the gap-filling sonar system and the side-scan sonar system; in this embodiment, the altimeter is installed below the rear end of the towed body to measure the height of the towed body from the seabed ground.

[0047] As Figure 4 shown, in one embodiment, the full-coverage sonar detection device of the present invention further includes a hull. The hull is connected to the towed body through a towing system. The towing system is composed of a winch and a towing cable, etc. The lowering and recovery of the towed body are realized through the towing system, and data transmission between the hull and the towed body is achieved; the hull and the towing system do not involve the inventive points of the present invention and will not be elaborated here.

[0048] As Figure 5As shown, in one embodiment, a housing is provided at the front end of the drag body. The forward-looking transmitting transducer array and the forward-looking receiving transducer array of the seam-filling sonar system are both placed in the housing. The forward-looking transmitting transducer array is distributed in an arc in the housing, and the forward-looking receiving transducer array is distributed in a straight line in the housing. The beam opening angles of the forward-looking transmitting transducer array and the forward-looking receiving transducer array in the plane perpendicular to the advancing direction of the drag body are β, and the beam opening angles of the forward-looking transmitting transducer array and the forward-looking receiving transducer array in the plane coinciding with the advancing direction of the drag body are θ. Among them, β≥2θm, so that the detection area below the seam-filling sonar system can seamlessly make up for the detection blind area of the side-scan sonar system, solve the problem of the detection blind area existing in the side-scan sonar system, and improve the detection coverage area of the detection equipment. In this embodiment, θ = 20°, β = 90°, and θm is the detection blind area angle directly below the unilateral side-scan transducer array. In this embodiment, the forward-looking transmitting transducer array is distributed in an arc in the housing. On the one hand, it is to ensure the detection of the area in front and below of the seam-filling sonar, and on the other hand, it is to ensure the hydrodynamic structure design of the towed body and reduce the hydrodynamic resistance of the towed body.

[0049] As Figure 7 shown, specifically, the housing is composed of functional module circuit boards such as a power supply circuit board, a transmitting power amplifier circuit board, a receiving conditioning circuit board, an AD acquisition circuit board, an FPGA control circuit board, and a seam-filling sonar bottom board. The receiving conditioning circuit board is used to receive weak underwater acoustic echo signals, filter, amplify and other processes them, and then transmit them to the AD acquisition circuit board for analog-to-digital conversion. The AD acquisition circuit board transmits the converted digital signal to the FPGA control circuit board. The FPGA control circuit board performs band-pass filtering, quadrature demodulation, packing, uploading and other processes on the digital signal, and finally performs pulse compression, beam forming, and imaging processing in the computer on the hull. The transmitting power amplifier circuit board amplifies the PWM transmission signal and then drives the seam-filling sonar system.

[0050] To improve the imaging quality of the detection image of the seam-filling sonar system of the present invention, the present invention collects the echo data in the beam center area of the seam-filling sonar system for mapping and display to form the detection image of the seam-filling sonar system. Since the echo signal intensity in the beam center area of the seam-filling sonar system is higher than the echo signal intensity outside the beam center area of the seam-filling sonar system, the detection image quality corresponding to the echo data based on the beam center area of the seam-filling sonar system is finer and it is easier to detect the detection target.

[0051] Under the condition that the echo data in the beam center area of the seam-filling sonar system is mapped and displayed to show the detection image, it is necessary to splice the detection image collected by the seam-filling sonar system and the detection image collected by the side-scan sonar system to ensure that the detection image of the spliced seam-filling sonar system and the detection image collected by the side-scan sonar system are in the same horizontal strip area perpendicular to the advancing direction of the drag body, so as to ensure the integrity of the splicing of the detection images of the two systems.

[0052] To achieve the effect that the detection image of the splicing seam sonar system of the present invention and the detection image collected by the side-scan sonar system are in the same horizontal strip area perpendicular to the advancing direction of the towing body, the principle of action of the detection image collected by the full-coverage sonar detection device of the present invention is as follows.

[0053] Select the sampling straight line l1 corresponding to the beam center area of the seam sonar system; the seabed ground is uneven, but the detection beam corresponding to the beam center area of the seam sonar system is always on the same sampling straight line l1. As the full-coverage sonar detection device moves, the sampling straight line l1 also moves synchronously.

[0054] Select the sampling starting point S1 of the detection image of the seam sonar system; the horizontal strip area corresponding to the sampling starting point S1 is the detection image formed by mapping the echo data of the beam center area of the seam sonar system, and the sampling starting point S1 is located on the sampling straight line l1, and the sampling starting point S1 is located at the intersection of the sampling straight line l1 and the seabed ground.

[0055] Obtain the detection image of the seam sonar system; as the full-coverage sonar detection device moves, the sampling starting point S1 also moves synchronously, and the horizontal strip area corresponding to the sampling starting point S1 also moves synchronously, thereby forming the detection image of the seam sonar system.

[0056] Select the sampling straight line l2 corresponding to the beam center area of one of the side-scan transducer arrays in the side-scan sonar system; the side-scan transducer array is composed of a plurality of side-scan transducers arranged along the length direction of the towing body; in this embodiment, one of the side-scan transducers in the side-scan transducer array is the side-scan transducer at the center of the side-scan transducer array, and the sampling straight line l2 corresponding to the beam center area of one of the side-scan transducers in the side-scan transducer array is the sampling straight line l2 corresponding to the beam center area of the side-scan transducer at the center of the side-scan transducer array; alternatively, one of the side-scan transducers in the side-scan transducer array can also be set as the side-scan transducer closest to the seam sonar system in the side-scan transducer array; the seabed ground is uneven, but the detection beam corresponding to the beam center area of the side-scan transducer array is always on the same sampling straight line l2. As the full-coverage sonar detection device moves, the sampling straight line l2 also moves synchronously.

[0057] Select the sampling starting point S2 of the detection image corresponding to the side-scan transducer; the horizontal strip area corresponding to the sampling starting point S2 is the detection image formed by mapping the echo data of the beam center area of the side-scan transducer, and the sampling starting point S2 is located on the sampling straight line l2, and the sampling starting point S2 is located at the intersection of the sampling straight line l2 and the seabed ground.

[0058] Acquire the detection image of the side-scan sonar system; as the full-coverage sonar detection equipment moves, the sampling starting point S2 also moves synchronously, and the lateral strip area corresponding to the sampling starting point S2 also moves synchronously, and the detection images collected by the two side scanning sonar arrays of the side-scan sonar system are combined to form the detection image of the side-scan sonar system.

[0059] The distance d between the sampling starting point S1 and the sampling starting point S2 along the length direction of the towed body is obtained, that is, the distance d between the gap filling sonar system and the side scan transducer along the length direction of the towed body is obtained; in this embodiment, d=L / 2, L is the total length of the towed body, and the side scan transducer is a side scan transducer located at the center of the side scan transducer array.

[0060] In the detection image of the gap filling sonar system, a detection image after a preset time t from the start of sampling of the gap filling sonar system is intercepted, and then puzzled with the detection image of the side scan sonar system to form a detection image of the full coverage sonar detection equipment, so as to ensure that the puzzle area of ​​the detection image of the gap filling sonar system and the detection image of the side scan sonar system are within the same transverse strip area perpendicular to the forward direction of the towed body; in this embodiment, the sampling start time of the visual sonar system is not later than the sampling start time of the side scan sonar system, and the sampling start time of the visual sonar system differs from the sampling start time of the side scan sonar system by t2 time, t=t1+t2=d / V+t2, t1=d / V, V is the moving speed of the towed body; wherein, the method of puzzleing the detection image of the gap filling sonar system and the detection image of the side scan sonar system does not involve the inventive point of the present invention, and can be implemented by the existing puzzle processing method, which need not be elaborated here.

[0061] In this embodiment, when t2=0, the sampling start time of the gap-filling sonar system is consistent with the sampling start time of the side-scan sonar system, and t=t1=d / V to ensure that the puzzle areas of the detection image of the gap-filling sonar system and the detection image of the side-scan sonar system are within the same transverse strip area perpendicular to the forward direction of the towed body.

[0062] Furthermore, during the movement of the full-coverage sonar detection equipment, multiple echo signals will be generated for the same detection point on the seabed or ground. In order to reduce the computing power burden of the gap-filling sonar system and reduce the interference of redundant echo signals in the gap-filling sonar system, the full-coverage sonar detection equipment of the present invention also adopts the following principle to collect detection images.

[0063] like Figure 8As shown in the figure, the preset seam sonar system has a collection length of ΔD along the traveling direction of the towed body in each working cycle T. This collection length ΔD is not greater than H*tanα - H*tan(α - θ / 2), and preferably, the collection length ΔD = H*tanα - H*tan(α - θ / 2); where H is the height of the towed body from the seabed ground, θ is the beam opening angle of the forward-looking receiving transducer array in the plane coinciding with the traveling direction of the towed body, and α is the angle between the forward-looking receiving transducer array and the plane perpendicular to the traveling direction of the towed body. Specifically, α is the angle between the sampling straight line l1 corresponding to the beam center region and the plane perpendicular to the traveling direction of the towed body.

[0064] To reduce the computing power burden of the seam sonar system and reduce the interference of redundant echo signals in the seam sonar system, the working cycle T of the seam sonar system of the present invention satisfies: VT = ΔD, so that the echo signals collected by the seam sonar system are reduced, and the effective detection effect on the seabed ground can be ensured.

[0065] As Figures 4 to 8 shown, a method for realizing a full-coverage sonar detection device of the present invention includes the following steps:

[0066] S1. Select the sampling straight line l1 corresponding to the beam center region of the seam sonar system; the seabed ground is uneven, but the detection beam corresponding to the beam center region of the seam sonar system is always on the same sampling straight line l1. As the full-coverage sonar detection device moves, this sampling straight line l1 also moves synchronously; specifically, this sampling straight line l1 is the angular bisector of the beam opening angle of the forward-looking receiving transducer array in the plane coinciding with the traveling direction of the towed body.

[0067] S2. Select the sampling starting point S1 of the detection image of the seam sonar system; the lateral strip region corresponding to this sampling starting point S1 is the detection image formed by mapping the echo data of the beam center region of the seam sonar system, and the sampling starting point S1 is located on this sampling straight line l1, and the sampling starting point S1 is located at the intersection of this sampling straight line l1 and the seabed ground.

[0068] S3. Obtain the detection image of the seam sonar system; as the full-coverage sonar detection device moves, this sampling starting point S1 also moves synchronously, and the lateral strip region corresponding to this sampling starting point S1 also moves synchronously, thereby forming the detection image of the seam sonar system.

[0069] S4. Select a sampling line l2 corresponding to the beam center region of one of the side-scan transducers in the side-scan sonar system. The side-scan transducer array is composed of multiple side-scan transducers arranged along the length direction of the towing body. In this embodiment, one of the side-scan transducers in the side-scan transducer array is the side-scan transducer at the center of the side-scan transducer array, and the sampling line l2 corresponding to the beam center region of one of the side-scan transducers in the side-scan transducer array is the sampling line l2 corresponding to the beam center region of the side-scan transducer at the center of the side-scan transducer array. Alternatively, one of the side-scan transducers in the side-scan transducer array can also be set as the side-scan transducer closest to the gap sonar system in the side-scan transducer array. The seabed ground is uneven, but the detection beam corresponding to the beam center region of the side-scan transducer array is always on the same sampling line l2. As the full-coverage sonar detection device moves, the sampling line l2 also moves synchronously. Specifically, the sampling line l2 is the angular bisector of the beam opening angle of the side-scan transducer in the plane coinciding with the traveling direction of the towing body.

[0070] S5. Select the sampling starting point S2 of the detection image corresponding to the side-scan transducer. The transverse strip region corresponding to the sampling starting point S2 is the detection image formed by mapping the echo data of the beam center region of the side-scan transducer, and the sampling starting point S2 is located on the sampling line l2 and at the intersection of the sampling line l2 and the seabed ground.

[0071] S6. Obtain the detection image of the side-scan sonar system. As the full-coverage sonar detection device moves, the sampling starting point S2 also moves synchronously, and the transverse strip region corresponding to the sampling starting point S2 also moves synchronously. Combining the detection images collected by the two side-scan sonar arrays of the side-scan sonar system, the detection image of the side-scan sonar system is jointly formed.

[0072] S7. Obtain the distance d between the sampling starting point S1 and the sampling starting point S2 along the length direction of the towing body, that is, obtain the distance d between the gap sonar system and the side-scan transducer along the length direction of the towing body. In this embodiment, d = L / 2, where L is the total length of the towing body, and the side-scan transducer is the side-scan transducer at the center of the side-scan transducer array.

[0073] S8. In the detection image of the gap filling sonar system, intercept the detection image after the preset time t of sampling start of the gap filling sonar system, and then jigsaw the detection image of the side scan sonar system to form a detection image of the full coverage sonar detection equipment, so as to ensure that the jigsaw area of ​​the detection image of the gap filling sonar system and the detection image of the side scan sonar system are within the same transverse strip area perpendicular to the forward direction of the towed body; in this embodiment, the sampling start time of the visual sonar system is not later than the sampling start time of the side scan sonar system, and the sampling start time of the visual sonar system differs from the sampling start time of the side scan sonar system by t2 time, t=t1+t2=d / V+t2, t1=d / V, V is the moving speed of the towed body; wherein, the method of jigsaw the detection image of the gap filling sonar system and the detection image of the side scan sonar system does not involve the inventive point of the present invention, and can be implemented by the existing jigsaw processing method, which is not necessary to elaborate here.

[0074] In this embodiment, when t2=0, the sampling start time of the gap-filling sonar system is consistent with the sampling start time of the side-scan sonar system, and t=t1=d / V to ensure that the puzzle areas of the detection image of the gap-filling sonar system and the detection image of the side-scan sonar system are within the same transverse strip area perpendicular to the forward direction of the towed body.

[0075] In one embodiment, the method of obtaining the detection image of the gap filling sonar system in step S3 is specifically performed as follows:

[0076] The acquisition length of the preset gap filling sonar system along the traveling direction of the towed body in each working cycle T is ΔD, and the acquisition length ΔD is not greater than H*tanα-H*tan(α-θ / 2); wherein H is the height of the towed body from the seabed, θ is the beam opening angle of the forward-looking receiving transducer array on the plane coinciding with the traveling direction of the towed body, α is the angle between the forward-looking receiving transducer array and the plane perpendicular to the traveling direction of the towed body, specifically, α is the angle between the sampling straight line l1 corresponding to the center area of ​​the beam and the plane perpendicular to the traveling direction of the towed body;

[0077] As the full-coverage sonar detection equipment moves, the sampling starting point S1 also moves synchronously, and the lateral strip area corresponding to the sampling starting point S1 moves synchronously, thereby forming a detection image of the gap sonar system; wherein, the working cycle T of the gap sonar system satisfies: VT=ΔD, thereby reducing the echo signals collected by the gap sonar system and ensuring the effective detection effect of the seabed and ground; in this embodiment, by making the full-coverage sonar detection equipment advance a distance of ΔD in each working cycle of the gap sonar system, the problem of repeated detection of the same detection point on the seabed and ground by the central beam of the gap sonar system is effectively avoided, and the interference of redundant echo signals in the gap sonar system is reduced; in addition, within the working cycle T of the gap sonar system, the seabed and ground directly below the full-coverage sonar detection equipment can be regarded as a horizontal plane.

[0078] In one embodiment, the acquisition length ΔD = H * tanα - H * tan(α - θ / 2), thereby effectively reducing the computing power burden of the seam sonar system and reducing the interference of redundant echo signals in the seam sonar system.

[0079] In the effectiveness diagram of the seam sonar system and the sidescan sonar system in the full-coverage sonar detection device of the present invention, the upper fan-shaped area is the imaging effect of the seam sonar detection, and the lower part is the imaging effect of the sidescan sonar detection. The black part in the middle of the sidescan sonar detection imaging is the detection blind area. Under this condition, the range of the detection blind area directly below the sidescan sonar is between 33m and 35m, and the coverage range of the seam sonar sound diagram is between 62.8m and 94.2m. Therefore, the seam detection range can completely cover the detection blind area directly below the sidescan sonar, thereby achieving the full-coverage detection effect.

[0080] Compared with the prior art, the beneficial effects of the full-coverage sonar detection device and its implementation method of the present invention are as follows:

[0081] 1. Design the forward-looking sonar system as a seam sonar system, and cooperate with installing the forward-looking transmitting transducer array and the forward-looking receiving transducer array obliquely downward at the front end below the drag body, so that the seam sonar system can not only detect obstacles in front like a traditional forward-looking sonar system, but also detect the detection area below the moving direction of the drag body to make up for the problem that the sidescan sonar system cannot scan the detection blind area.

[0082] 2. Use the seam sonar system to detect the seabed, which has advantages such as high resolution and clear imaging. Since its beam is larger in the plane coinciding with the moving direction of the drag body, it can search for targets in front of the towed body multiple times, especially in the field of underwater rescue, with higher search efficiency.

[0083] 3. Select the detection image data of the seam sonar system and piece together the detection image data of the sidescan sonar system to achieve full coverage of the detection area; on the one hand, according to the moving speed V and the height H from the seabed of the towed body, accurately select the echo data of the beam center point for mapping and display; on the other hand, since the seam sonar system is configured at the front end of the towed body and the sidescan sonar system is configured on both sides of the middle of the towed body, the image data detected by the seam sonar system at the same moment and the image data detected by the sidescan sonar are not in the same strip area horizontally. Therefore, it is necessary to select the images in the same strip area according to the length L and the moving speed V of the towed body for piecing together to ensure that the pieced images are in the same horizontal strip area perpendicular to the moving direction of the towed body.

[0084] In summary, in a full-coverage sonar detection device and its implementation method of the present invention, a gap sonar system is arranged below the front end of the towed body. By cooperating with the forward-looking transmitting transducer array and the forward-looking receiving transducer array of the gap sonar system, both are installed obliquely downward below the front end of the towed body, so as to detect the detection area below the traveling direction of the towed body, thereby making up for the problem that the side-scan sonar system cannot scan the detection blind area, and further improving the detection coverage area of the detection device.

[0085] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0086] In several embodiments provided by the present invention, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative. For example, the division of each unit is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0087] The steps in the method embodiments of the present invention can be adjusted, combined, and deleted according to actual needs. The units in the device embodiments of the present invention can be combined, divided, and deleted according to actual needs. In addition, the functional units in each embodiment of the present invention can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a device (which can be a personal computer, a terminal, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention.

[0088] The above-described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

Claims

1. A full-coverage sonar detection device, comprising a towing body and a side-scan sonar system. The side-scan sonar system includes two side-scan transducer arrays, and the two side-scan transducer arrays are respectively arranged on both sides of the middle part of the towing body. It is characterized in that, It also includes a gap-filling sonar system, which includes a forward-looking transmitting transducer array and a forward-looking receiving transducer array. The gap-filling sonar system is placed below the front end of the towed body, and the forward-looking transmitting transducer array and the forward-looking receiving transducer array are both installed obliquely downward below the front end of the towed body.

2. The full-coverage sonar detection device according to claim 1, wherein The installation heights of the gap-filling sonar system and the side-scan sonar system on the towed body are consistent.

3. The full-coverage sonar detection device according to claim 1, wherein The bottom end of the towing body is also provided with an altimeter which is installed below the rear end of the towing body and is used to measure the height of the towing body from the seabed.

4. The full-coverage sonar detection device according to claim 1, characterized in that A housing is provided at the front end of the drag body. The forward-looking transmitting transducer array and the forward-looking receiving transducer array of the gap sonar system are both placed in the housing. The beam opening angle of the forward-looking transmitting transducer array and the forward-looking receiving transducer array in the plane perpendicular to the traveling direction of the drag body is β, and the beam opening angle of the forward-looking transmitting transducer array and the forward-looking receiving transducer array in the plane coinciding with the traveling direction of the drag body is θ; It is the detection blind area angle directly below the unilateral side-scan transducer array.

5. The full-coverage sonar detection device according to claim 4, characterized in that, The forward-looking transmitting transducer array is distributed in an arc in the shell, and the forward-looking receiving transducer array is distributed in a straight line in the shell.

6. The full-coverage sonar detection device according to claim 1, characterized in that, The vessel also includes a hull, which is connected to the towing body through a towing system.

7. A method for implementing a full-coverage sonar detection device, characterized in that, The steps include: S1, select the sampling line l1 corresponding to the center area of ​​the beam of the gap filling sonar system; S2, select the sampling starting point S1 of the detection image of the crack filling sonar system; the sampling starting point S2 is located at the intersection of the sampling straight line l2 and the seabed ground; S3, obtaining the detection image of the gap filling sonar system; S4, selecting a sampling line l2 corresponding to a central area of ​​a side scan transducer beam of a side scan transducer array in a side scan sonar system; the side scan transducer array is composed of a plurality of side scan transducers arranged along the length direction of the towed body; S5, selecting the sampling starting point S2 of the detection image corresponding to the side scan transducer; the sampling starting point S2 is located at the intersection of the sampling straight line l2 and the seabed surface; S6, acquiring a detection image of a side-scan sonar system; S7, obtaining the distance d between the sampling starting point S1 and the sampling starting point S2 along the length direction of the dragging body; S8. In the detection image of the gap-filling sonar system, capture the detection image after the preset time t of sampling start of the gap-filling sonar system, and then piece it together with the detection image of the side-scan sonar system to form a detection image of the full-coverage sonar detection equipment; the sampling start time of the visual sonar system is no later than the sampling start time of the side-scan sonar system, and the sampling start time of the visual sonar system differs from the sampling start time of the side-scan sonar system by a time length of t2, t=t1+t2=d / V+t2, t1=d / V, V is the moving speed of the towed body.

8. The implementation method of the full-coverage sonar detection device according to claim 7, characterized in that, In step S8, when t2=0, the sampling start time of the gap filling sonar system is consistent with the sampling start time of the side scan sonar system, t=t1=d / V.

9. The implementation method of the full-coverage sonar detection device according to claim 7, characterized in that, The method of step S3, obtaining the detection image of the crack-filling sonar system, is specifically performed as follows: The acquisition length of the preset gap filling sonar system along the traveling direction of the towed body in each working cycle T is ΔD, and the acquisition length ΔD is not greater than H*tanα-H*tan(α-θ / 2); wherein H is the height of the towed body from the seabed, θ is the beam opening angle of the forward-looking receiving transducer array on the plane coinciding with the traveling direction of the towed body, and α is the angle between the forward-looking receiving transducer array and the plane perpendicular to the traveling direction of the towed body; As the full-coverage sonar detection equipment moves, the sampling starting point S1 also moves synchronously, and the lateral strip area corresponding to the sampling starting point S1 also moves synchronously, thereby forming a detection image of the gap-filling sonar system; wherein, the working cycle T of the gap-filling sonar system satisfies: VT=ΔD.

10. The implementation method of the full-coverage sonar detection device according to claim 9, characterized in that The acquisition length ΔD = H * tanα - H * tan(α - θ / 2).

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