Shallow water target positioning system and method

Abstract

The present invention relates to the field of underwater positioning technology, and discloses a shallow water target positioning system and method. The shallow water target positioning system includes a surface support platform, underwater operating equipment, a pull-wire sensor, a first reference point, and a spatial posture sensor. The pull-wire sensor is arranged between the underwater operating equipment and the surface support platform, and the first reference point is arranged at the surface connection portion between the surface support platform and the pull-wire sensor. The surface support platform is also provided with a spatial posture sensor for detecting the spatial coordinates of the first reference point. The method includes: deploying the underwater operating equipment and constructing a spatial coordinate system based on the connection points; obtaining length data of the pull-wire sensor and the spatial coordinates of the first reference point, and calculating the coordinates of the underwater operating equipment based on the length data, the first reference point, and the spatial coordinates of the connection points. The coordinates of the underwater operating equipment can be quickly and accurately obtained through the reference point and the positioning wire rope, thereby solving the problem that underwater operating equipment in shallow water areas cannot accurately obtain positioning.

Description

Technical Field

[0001] The present invention relates to the field of underwater positioning technology, and in particular to a shallow water target positioning system and method. Background Art

[0002] When conducting hydrological research and exploring seabed resources, underwater operating equipment is needed to meet survey needs. However, in the process of performing survey tasks, it is necessary to obtain the location of underwater operating equipment in real time to assist in the survey tasks.

[0003] Although the GPS positioning and optical positioning commonly used on land are of relatively high accuracy, the electromagnetic waves attenuate too much in water, resulting in that these commonly used systems on shore cannot be used underwater. The commonly used methods underwater are ultra-short baselines, short baselines or long baselines based on hydroacoustics. When the target is deep in the water, these positioning systems can achieve relatively good positioning effects. However, in shallow water areas, such as inland lakes, inland rivers and offshore areas, these acoustic positioning systems cannot accurately obtain the target's location information due to reasons such as acoustic detection angle and water pollution, and thus cannot perform geographic annotation on the survey results. Once the underwater operating equipment is detached, it will cause serious economic losses. The existing shallow water area positioning is often achieved by setting a rope at a fixed end on the shore and connecting the other end to the operating equipment. The angle of the rope is obtained by the sensor, and the position of the operating equipment is obtained based on the rope length and trigonometric functions.

[0004] However, this calculation method cannot accurately determine the angle of a single axis due to the coupling of the X, Y, and Z axes when the mechanical sensor obtains the angle, resulting in an inability to effectively measure the position of the operating equipment. In addition, please refer to Figure 1 When the mechanical sensor obtains the angle, it needs to be subjected to the force of the rope to feedback the angle information. Figure 1 In the figure, when the rope moves from point E to point F, the mechanical sensor cannot bear the force and therefore cannot feedback the angle information. The EF segment becomes a dead zone, making it impossible to accurately measure the position of the underwater operating equipment. Summary of the Invention

[0005] The present invention provides a shallow water target positioning system and method to solve the problem that existing underwater operating equipment in shallow water areas cannot be accurately positioned.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, the present invention provides a shallow water target positioning system, comprising a surface support platform, underwater operating equipment, a drawstring sensor, and a spatial posture sensor, wherein the drawstring sensor is disposed between the underwater operating equipment and the surface support platform, a first reference point is provided at the surface connection portion between the surface support platform and the drawstring sensor, and the surface support platform is further provided with a spatial posture sensor for detecting the spatial coordinates of the first reference point;

[0008] The pull rope sensor includes a sensor body and a positioning wire rope. One end of the sensor body is arranged on the underwater operation equipment, and the positioning wire rope is connected to the water surface support platform.

[0009] Furthermore, a second reference point is set at the water surface connection portion between the water surface support platform and the pull rope sensor.

[0010] Furthermore, the underwater operation equipment is connected to the surface support platform via an optoelectronic watertight cable, and a plurality of buoys are installed on the outer surface of the optoelectronic watertight cable.

[0011] Furthermore, the surface support platform is installed with a support frame and a winch, one end of the optoelectronic watertight cable is connected to the underwater operating equipment, and the other end is connected to the winch on the surface support platform through the support frame.

[0012] In a second aspect, the present invention provides a shallow water target positioning method, which is applied to any of the shallow water target positioning systems described above, and the shallow water target positioning method includes:

[0013] Step 1: Deploy the underwater operation equipment underwater to carry out underwater operations, and build a spatial coordinate system based on the connection points between the rope sensor and the surface support platform;

[0014] Step 2: Obtain the length data of the rope sensor and the spatial coordinates of the first reference point, and calculate the coordinates of the underwater operating equipment in the spatial coordinate system based on the length data of the rope sensor, the first reference point and the spatial coordinates of the connection point.

[0015] Furthermore, a second reference point is set at the water surface connection portion between the water surface support platform and the pull rope sensor;

[0016] The step 2 also includes: obtaining the length data of the rope sensor and the spatial coordinates of the first reference point and the second reference point, and calculating the coordinates of the underwater operation equipment in the spatial coordinate system based on the length data of the rope sensor and the spatial coordinates of the first reference point and the second reference point.

[0017] Furthermore, the coordinates of the underwater working equipment in the spatial coordinate system are calculated based on the length data of the rope sensor, the spatial coordinates of the first reference point, the spatial coordinates of the connection point or the second reference point in combination with the Pythagorean theorem and similar triangles. The coordinates of the underwater working equipment are calculated by the length data of the rope sensor, the spatial coordinates of the first reference point and the connection point, or by the length data of the rope sensor, the spatial coordinates of the first reference point and the spatial coordinates of the second reference point.

[0018] Furthermore, the coordinates of the underwater operating equipment in the space coordinate system are calculated using the following formula:

[0019] ;

[0020] ;

[0021] ;

[0022] in, 、 、 are the X, Y, and Z axis coordinate positions of the underwater operating equipment in the spatial coordinate system;

[0023] 、 、 are the X, Y, and Z axis coordinate positions of the connection point or the second reference point in the spatial coordinate system respectively;

[0024] is the length data of the rope sensor;

[0025] 、 、 They are the ratios of the spatial vectors of the X, Y, and Z axes of the first reference point coordinates to the length from the first reference point to the water surface support platform.

[0026] Furthermore, the 、 、 Calculated using the following formula:

[0027] ;

[0028] ;

[0029] ;

[0030] in, 、 、 are the X, Y, and Z axis coordinate positions of the first reference point in the spatial coordinate system respectively.

[0031] Beneficial effects:

[0032] The present invention provides a shallow water target positioning system and method. By combining a first reference point with a connection point, similar triangles and the Pythagorean theorem are used to quickly calculate the coordinates of underwater operating equipment in a spatial coordinate system. This solves the problem of underwater operating equipment being unable to accurately position itself in shallow water areas due to factors such as acoustic detection angle and water pollution.

[0033] The spatial posture sensor combined with the first reference point effectively solves the problem that mechanical sensors cannot accurately measure angles. One end of the wire rope of the pull rope sensor is set at one end of the water surface support platform. The spatial posture sensor is used to directly measure the angles of the X, Y, and Z axes without contact. There is no dead zone and no angle coupling phenomenon, which will not affect the positioning of underwater operating equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of a mechanical encoder subjected to a pull rope-transmitted force, which is the background technology of the present invention;

[0035] Figure 2 is a schematic diagram of a shallow water target positioning system according to an embodiment of the present invention;

[0036] Figure 3 Detailed schematic diagram of a shallow water target positioning system according to an embodiment of the present invention;

[0037] Figure 4 is a system block diagram of a shallow water target positioning system according to an embodiment of the present invention;

[0038] Figure 5 This is a flow chart of a shallow water target positioning method according to an embodiment of the present invention;

[0039] Figure 6 This is a schematic diagram of setting the first reference point B and the second reference point A of the shallow water target positioning method according to an embodiment of the present invention;

[0040] Figure 7 Schematic diagram of setting the third reference point C in the verification process of the shallow water target positioning method according to an embodiment of the present invention;

[0041] Figure 8 This is a schematic diagram of the solution of a quadratic equation with AD variables in the verification process of the shallow water target positioning method according to an embodiment of the present invention.

[0042] In the figure, 1. Surface support platform; 2. Underwater operation equipment; 3. Pull rope sensor; 31. Sensor body; 32. Positioning wire rope; 4. First reference point; 41. Second reference point; 5. Spatial posture sensor; 6. Photoelectric watertight cable; 61. Float; 11. Support frame; 12. Winch. DETAILED DESCRIPTION

[0043] The following is a clear and complete description of the technical solutions of the present invention. It should be understood that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0044] Unless otherwise defined, technical or scientific terms used in this invention shall have the same ordinary meaning as understood by persons of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not denote any order, quantity, or importance, but are merely used to distinguish different components.

[0045] See Figure 2-3 An embodiment of the present application provides a shallow water target positioning system, including a surface support platform 1, an underwater operating equipment 2, a pull-wire sensor 3 and a spatial posture sensor 5. The pull-wire sensor 3 is arranged between the underwater operating equipment 2 and the surface support platform 1. A first reference point 4 is set at the surface connection part between the surface support platform 1 and the pull-wire sensor 3. The surface support platform 1 is also provided with a spatial posture sensor 5 for detecting the spatial coordinates of the first reference point 4, and a second reference point 41 is set at the surface connection part between the surface support platform 1 and the pull-wire sensor 3.

[0046] Specifically, the pull rope sensor 3 includes a sensor body 31 and a positioning wire rope 32 . One end of the sensor body 31 is disposed on the underwater operating equipment 2 , and the positioning wire rope 32 is connected to the surface support platform 1 .

[0047] The underwater operation equipment 2 is also connected to the surface support platform 1 through an optoelectronic watertight cable 6 , and a plurality of buoys 61 are installed on the outer surface of the optoelectronic watertight cable 6 .

[0048] Among them, the surface support platform 1 is installed with a support frame 11 and a winch 12. One end of the optoelectronic watertight cable 6 is connected to the underwater operating equipment 2, and the other end is connected to the winch 12 on the surface support platform 1 through the support frame 11.

[0049] The spatial posture sensor 5 includes a plurality of camera probes, and all of them are horizontally arranged above the first reference point 4 .

[0050] For corresponding Figure 4 A control computer and an on-water optical terminal are set on the surface support platform 1, connected to the optical spatial posture system composed of the spatial posture sensor 5, and a pressure-resistant electronic compartment is set in the underwater operation equipment 2, in which the underwater optical terminal, the local controller and the pull rope sensor 3 are set;

[0051] The local controller collects data from the rope sensor 3 and the length data of the positioning wire rope 32 through the serial port, and then transmits it to the underwater optical terminal through Ethernet. The underwater optical terminal converts the electrical signal into an optical signal, and transmits it to the surface optical terminal through the optical fiber in the optoelectronic watertight cable 6. The surface optical terminal converts the optical signal into an electrical signal, and transmits it to the control computer through Ethernet. The optical spatial posture system transmits the spatial coordinates of the first reference point 4 and the second reference point 41 on the positioning wire rope 32 to the control computer through Ethernet. The control computer calculates the coordinates of the underwater operating equipment 2 by obtaining the spatial coordinates of the first reference point 4 and the second reference point 41 and the length data of the positioning wire rope 32.

[0052] In this embodiment, the control computer calculates the coordinates of the underwater working equipment 2 through the spatial coordinates of the first reference point 4 and the second reference point 41 and the length data of the positioning wire rope 32. In other embodiments where the second reference point 41 is not set and only the connection point is set, the control computer calculates the coordinates of the underwater working equipment 2 through the spatial coordinates of the first reference point 4 and the connection point and the length data of the positioning wire rope 32.

[0053] See Figure 5-6 The embodiment of the present application further provides a shallow water target positioning method, which is applied to a shallow water target positioning system. The shallow water target positioning system includes a surface support platform 1, an underwater operating device 2, a drawstring sensor 3, a first reference point 4, and a spatial posture sensor 5. The drawstring sensor 3 is arranged between the underwater operating device 2 and the surface support platform 1. The first reference point 4 is arranged at the surface connection portion between the surface support platform 1 and the drawstring sensor 3. The surface support platform 1 is further provided with a spatial posture sensor 5 for detecting the spatial coordinates of the first reference point 4, and a second reference point 41 is arranged at the surface connection portion between the surface support platform 1 and the drawstring sensor 3.

[0054] Shallow water target positioning methods include:

[0055] Step 1: Deploy the underwater operation equipment 2 underwater to carry out underwater operations, and construct a spatial coordinate system based on the connection points between the pull-wire sensor 3 and the surface support platform 1;

[0056] In this embodiment, the entire process is completed in a laboratory, a shallow water target positioning system is set up accordingly, and the underwater operation equipment 2 is placed at a certain distance from the surface support platform 1 to simulate actual underwater operations.

[0057] See Figure 7 In this embodiment, a third reference point is set on the underwater working equipment 2 for verification, the spatial coordinates of the third reference point are obtained by the spatial posture sensor 5, and the distance between the third reference point and the positioning wire rope 32 is measured by a measuring instrument;

[0058] Wherein O is the connection point, B is the first reference point 4, A is the second reference point 41, C is the third reference point, and D is the position of the positioning wire rope 32 on the underwater operation equipment 2.

[0059] Step 2: Obtain the length data of the rope sensor 3 and the spatial coordinates of the first reference point 4 and the second reference point 41, and calculate the coordinates of the underwater working equipment 2 in the spatial coordinate system based on the length data of the rope sensor 3 and the spatial coordinates of the first reference point 4 and the second reference point 41.

[0060] In this embodiment, the coordinates of the underwater working equipment 2 in the spatial coordinate system are calculated based on the length data of the rope sensor, the spatial coordinates of the first reference point 4, the spatial coordinates of the second reference point 41, combined with the Pythagorean theorem and similar triangles. In other embodiments, only the connection point can be set according to actual conditions, and there is no need to set the second reference point 41. The coordinates are calculated based on the length data of the rope sensor, the spatial coordinates of the first reference point 4, the spatial coordinates of the connection point, combined with the Pythagorean theorem and similar triangles.

[0061] The length data AD of the rope sensor 3 obtained at this time is 2601 mm, the spatial coordinates of the first reference point 4 are (-784.351, -348.054, 1496.193), the spatial coordinates of the second reference point 41 are (-922.27, -349.677, 1544.523), and the spatial coordinates of the third reference point are (1596.323, -160.879, 776.904). The distance CD between the third reference point and the positioning wire rope 32 is 195 mm.

[0062] The coordinates of the underwater operating equipment 2 in the space coordinate system are calculated using the following formula:

[0063] ;

[0064] ;

[0065] ;

[0066] in, 、 、 are the X, Y, and Z axis coordinate positions of the underwater operating equipment 2 in the spatial coordinate system;

[0067] 、 、 are respectively the X, Y, and Z axis coordinate positions of the second reference point 41 in the spatial coordinate system;

[0068] In this embodiment, 、 、 are the X, Y, and Z axis coordinate positions of the second reference point 41 in the spatial coordinate system. In other embodiments where only the connection point is set and the second reference point 41 is not set, 、 、 are the X, Y, and Z axis coordinate positions of the connection point in the spatial coordinate system respectively;

[0069] is the length data of the rope sensor 3 (in this embodiment, AD length);

[0070] 、 、 They are respectively the ratios of the spatial vectors of the X, Y, and Z axes of the coordinates of the first reference point 4 and the length from the first reference point 4 to the water surface support platform 1.

[0071] 、 、 Calculated using the following formula:

[0072] ;

[0073] ;

[0074] ;

[0075] in, 、 、 are respectively the X, Y, and Z axis coordinate positions of the first reference point 4 in the space coordinate system.

[0076] From the above formula and the Pythagorean theorem, we can know that the distance AB between the first reference point 4 and the second reference point 41 is:

[0077] ;

[0078] Further calculations yield =0.944, =0.011, =-0.331, combined with the length data S of the rope sensor 3 obtained as 2601mm, it can be calculated =1533.074mm, =-321.066mm, =683.592 mm, thus the coordinates of the underwater working equipment 2 in the space coordinate system are (1533.074, -321.066, 683.592).

[0079] The distance AC between the second reference point 41 and the third reference point is calculated again using the Pythagorean theorem as follows:

[0080] ;

[0081] in, 、 、 is the spatial coordinate of the third reference point.

[0082] The distance BC between the first reference point 4 and the third reference point is calculated as:

[0083] ;

[0084] Consider the first reference point 4, the second reference point 41, and the third reference point as a triangle and calculate using the cosine theorem. The cosine of :

[0085] ;

[0086] The position of the positioning wire rope 32 on the underwater operating equipment 2, the second reference point 41 and the third reference point are considered as a triangle. Combining the cosine theorem, we can know that:

[0087] ;

[0088] Among them, the CD length is the distance between the third reference point and the positioning wire rope 32, which is 195 mm, and the AC length is 2639.733 mm. The cosine of is 0.9973, so the above equation is a quadratic equation about AD variables, and the solution is is 2653.762mm, is 2611.450mm, see Figure 8 ,in , from this we can see that, The length is the length from the positioning wire rope 32 on the underwater operation equipment 2 to the second reference point 41. =2611.450mm is substituted into the following formula as S:

[0089] ;

[0090] ;

[0091] ;

[0092] in, 、 、 Obtained during the accounting process The coordinate position of the point on the X, Y, and Z axes in the spatial coordinate system;

[0093] get , , .

[0094] Further analysis is performed on the coordinates of point D calculated by the drawstring sensor 3 and the coordinates of point D calculated by inverse cosine deduction using the third reference point:

[0095] Table 1: Analysis of the coordinates of point D calculated by the draw wire sensor 3 and the coordinates of point D calculated by the third reference point

[0096]

[0097] As can be seen from Table 1, the deviation between the coordinates of point D calculated using the rope sensor 3 and the coordinates of point D calculated using the third reference point is very small. Therefore, it can be explained that the technical solution described in this application can accurately obtain the position information of the underwater working equipment 2 by setting a reference point on the rope sensor 3 and calculating the spatial coordinates of the reference point in combination with the length data of the positioning wire rope 32.

[0098] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A shallow water target positioning system, characterized in that: The invention comprises a surface support platform (1), an underwater operation device (2), a pull-wire sensor (3), and a spatial posture sensor (5), wherein the pull-wire sensor (3) is arranged between the underwater operation device (2) and the surface support platform (1), a first reference point (4) is arranged on the surface connection portion between the surface support platform (1) and the pull-wire sensor (3), and the surface support platform (1) is further provided with a spatial posture sensor (5) for detecting the spatial coordinates of the first reference point (4); The pull rope sensor (3) comprises a sensor body (31) and a positioning steel wire rope (32), one end of the sensor body (31) is arranged on the underwater operation equipment (2), and the positioning steel wire rope (32) is connected to the water surface support platform (1); Setting a second reference point (41) at the surface connection portion between the water surface support platform (1) and the pull rope sensor (3); The spatial posture sensor (5) transmits the spatial coordinates of the first reference point (4), the second reference point (41), and the connection point between the pull rope sensor (3) and the surface support platform (1) to the surface support platform (1), and the pull rope sensor (3) transmits the length data to the surface support platform (1). The surface support platform (1) calculates the coordinates of the underwater operation equipment (2) in the spatial coordinate system based on the length data and the spatial coordinates of the first reference point (4) and the connection point, or calculates the coordinates of the underwater operation equipment (2) in the spatial coordinate system based on the spatial coordinates of the first reference point (4) and the second reference point (41).

2. The shallow water target positioning system according to claim 1, characterized in that: The underwater operation equipment (2) is also connected to the surface support platform (1) via a photoelectric watertight cable (6), and a plurality of buoys (61) are installed on the outer surface of the photoelectric watertight cable (6).

3. The shallow water target positioning system according to claim 2, characterized in that: The surface support platform (1) is equipped with a support frame (11) and a winch (12); one end of the photoelectric watertight cable (6) is connected to the underwater operating equipment (2), and the other end is connected to the winch (12) on the surface support platform (1) through the support frame (11).

4. A shallow water target positioning method, characterized in that: The shallow water target positioning system according to any one of claims 1 to 3, wherein the shallow water target positioning method comprises: Step 1: deploy the underwater operation equipment (2) underwater to carry out underwater operations, and construct a spatial coordinate system based on the connection points between the pull-wire sensor (3) and the surface support platform (1); Step 2: Obtain the length data of the rope sensor (3), and obtain the spatial coordinates of the first reference point (4) and the second reference point (41), and calculate the coordinates of the underwater operating equipment (2) in the spatial coordinate system based on the length data of the rope sensor (3) and the spatial coordinates of the first reference point (4) and the connection point, or calculate the coordinates of the underwater operating equipment (2) in the spatial coordinate system based on the spatial coordinates of the first reference point (4) and the second reference point (41).

5. The shallow water target positioning method according to claim 4, characterized in that: The coordinates of the underwater operation equipment (2) in the spatial coordinate system are calculated based on the length data of the rope sensor (3), the spatial coordinates of the first reference point (4), the spatial coordinates of the connection point or the second reference point (41), and the Pythagorean theorem and similar triangles.

6. The shallow water target positioning method according to claim 5, characterized in that: The coordinates of the underwater operating equipment (2) in the space coordinate system are calculated using the following formula: ； ； ； in, 、 、 are the X, Y, and Z axis coordinate positions of the underwater operating equipment (2) in the spatial coordinate system; 、 、 are the X, Y, and Z axis coordinate positions of the connection point or the second reference point (41) in the spatial coordinate system; is the length data of the rope sensor (3); 、 、 They are respectively the ratios of the spatial vectors of the X, Y, and Z axes of the coordinates of the first reference point (4) to the length from the first reference point (4) to the water surface support platform (1).

7. The shallow water target positioning method according to claim 6, characterized in that: described 、 、 Calculated using the following formula: ； ； ； in, 、 、 are the X, Y, and Z axis coordinate positions of the first reference point (4) in the spatial coordinate system.

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