An underwater positioning system and method based on distributed positioning tags

Abstract

The present invention relates to an underwater positioning system and method based on distributed positioning tags. The system first uses a depth measurement module to determine the depth of a mold. A two-degree-of-freedom gyroscope is then used to record the horizontal and pitch angles of the unit. Distributed UWB ultra-wideband positioning tags are then used to determine the relative time difference of arrival. By algebraically solving a constrained single curve equation system, the position coordinates of the underwater target are obtained. The system not only prints relevant parameters and results on a liquid crystal display for later calibration, but also transmits the position coordinates to a master control terminal via a Beidou satellite communication system module. The system boasts a simple structure and is easy to operate. It can be attached to or placed on an underwater target, making it adaptable to various underwater environments.

Description

Technical Field

[0001] The present invention relates to the field of underwater positioning, and in particular to an underwater positioning system and method based on distributed positioning tags. Background Art

[0002] As China strengthens its management of oceans, lakes, and reservoirs, the development of underwater salvage equipment has become a hot topic in recent years. To accurately determine the location of underwater targets, researchers have developed numerous underwater detection devices, most of which utilize sonar and GPS. However, when a target is obstructed by other underwater objects, sonar cannot properly detect it, and thus its location information cannot be obtained. In complex underwater environments, GPS signals are weak and experience lag, resulting in significant positioning errors. With the advancement of communication technology, UWB technology has become increasingly mature, offering advantages such as low cost, low power consumption, and strong penetration, making it widely used in various underwater devices. A single UWB positioning tag is insufficient for underwater positioning. Arranging UWB positioning tags in a distributed array can effectively receive signals from all directions, thus achieving underwater positioning. Summary of the Invention

[0003] The purpose of the present invention is to provide an underwater positioning system and method based on distributed positioning tags to improve underwater positioning accuracy.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] An underwater positioning system based on distributed positioning tags, the positioning system comprising:

[0006] The positioning base station is set up at a fixed location on the shore or on the ship and is used to periodically transmit signals outward;

[0007] case;

[0008] A positioning tag, provided on the housing, for receiving a signal sent by the positioning base station;

[0009] a depth measurement module, disposed on the housing and configured to measure the depth of the housing underwater;

[0010] A two-degree-of-freedom gyroscope is provided on the housing and is used to measure the horizontal deflection angle and the pitch deflection angle of the housing;

[0011] Beidou satellite communication module for clock synchronization;

[0012] The processor is connected to the positioning base station, the positioning tag, the depth measurement module, the two-degree-of-freedom gyroscope and the Beidou satellite communication module, and is used to calculate the position coordinates of the shell.

[0013] Optionally, the upper surface of the shell is triangular.

[0014] Optionally, the positioning tag includes: a first antenna, a second antenna, a third antenna, a first high-precision clock, a second high-precision clock, and a third high-precision clock, and the first antenna, the second antenna and the third antenna are evenly distributed on the three corners of the shell.

[0015] Optionally, the positioning base station includes: a fourth antenna and a fourth high-precision clock.

[0016] Optionally, the positioning system further includes: a display connected to the processor, and configured to display the horizontal deflection angle, the pitch deflection angle, and the housing position coordinates.

[0017] Optionally, the Beidou satellite communication module includes: a Beidou communication antenna.

[0018] Optionally, the positioning system further includes: a power supply, an LED indicator light and a waterproof switch, and the power supply, LED indicator light and waterproof switch are arranged on the housing.

[0019] Based on the above system in the present invention, the present invention further provides an underwater positioning method of a distributed positioning tag, the positioning method comprising:

[0020] A depth measurement module is used to measure the depth H of the shell under water;

[0021] Measure the height h of the positioning base station from the water surface;

[0022] The height z of the housing from the positioning base station is obtained based on the depth H of the housing underwater and the height h of the positioning base station from the water surface; z=H+h;

[0023] A two-degree-of-freedom gyroscope is used to measure the horizontal deflection angle and the pitch deflection angle of the shell;

[0024] Construct a coordinate system with the center of the shell as the origin, and let the coordinates of the shell be (x, y, z);

[0025] Calculating the coordinate values ​​of the first antenna, the second antenna, and the third antenna in the positioning tag according to the horizontal deflection angle and the pitch deflection angle;

[0026] Obtaining the timestamps when the first antenna, the second antenna, and the third antenna in the positioning tag receive the signal sent by the positioning base station;

[0027] The position coordinates of the housing are calculated based on the time stamp and the coordinate values ​​of the first antenna, the second antenna, and the third antenna.

[0028] Optionally, the coordinate values ​​of the first antenna, the second antenna, and the third antenna in the positioning tag are calculated according to the horizontal deflection angle and the pitch deflection angle using the following formula:

[0029]

[0030] in, Represent the actual coordinate values ​​of the first antenna, the second antenna and the third antenna respectively, L is the distance between the first antenna, the second antenna and the third antenna and the center of the shell, α is the horizontal deflection angle, β is the pitch deflection angle, and z is the height of the shell from the positioning base station.

[0031] Optionally, the position coordinates of the housing are calculated based on the timestamp and the coordinate values ​​of the first antenna, the second antenna, and the third antenna using the following formula:

[0032]

[0033] Wherein, t1, t2, and t3 represent the timestamps corresponding to the signals received by the first antenna, the second antenna, and the third antenna, respectively, and c is the speed of light.

[0034] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0035] The present invention proposes an underwater positioning system and method based on distributed UWB distribution tags. The present invention has a simple structure and is easy to assemble. Unlike traditional underwater devices, no charging socket is provided, and a wireless charging mode is adopted, thereby improving the safety of the present invention. The UWB used in the present invention is a high-performance and high-gain antenna, which improves the signal penetration ability and reduces the attenuation rate, thereby improving the accuracy. In the present invention, the positioning base station and the positioning tag are simplex communication, and there will be no signal interference when multiple modules are used at the same time, so it can be used to achieve multi-module positioning. The present invention further improves the management efficiency of underwater equipment, is applicable to various complex underwater environments, and is also of great significance to the intelligent development of underwater reconnaissance and unmanned submersibles. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a schematic diagram of the structure of an underwater positioning system based on distributed positioning tags according to an embodiment of the present invention;

[0038] Figure 2Schematic diagram of the shell deflection angle according to an embodiment of the present invention.

[0039] Explanation of symbols:

[0040] First antenna 1, depth measurement module 2, display 3, second antenna 4, power LED indicator 5; Beidou communication antenna 6, waterproof switch 7, third antenna 8. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] The purpose of the present invention is to provide an underwater positioning system and method based on distributed positioning tags to improve underwater positioning accuracy.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Figure 1 This is a schematic diagram of the housing structure in an underwater positioning system based on distributed positioning tags according to an embodiment of the present invention. Figure 1 , the positioning system of the present invention includes: a positioning base station, a housing, a positioning tag, a depth measurement module 2, a two-degree-of-freedom gyroscope, a Beidou satellite communication module, a display 3, a power supply, an LED indicator, a waterproof switch 7 and a processor;

[0045] The positioning base station includes a fourth antenna, a UWB transceiver module, and a second high-precision clock. The base station is placed at a fixed location on the shore or on a ship, with the zero coordinate position established using due north as the positive x-axis and vertically upward as the positive z-axis. The coordinate system is constructed according to the right-hand rule. Signals are broadcast periodically, each with a unique tag. The UWB transceiver module can be used to transmit high-precision timestamps.

[0046] The housing of the present invention is triangular, wherein the sensor of the depth measurement module 2 is embedded in the upper surface of the housing, and the depth measurement sensor is used to measure the depth of the housing;

[0047] The positioning tag includes: a first antenna 1, a second antenna 4, a third antenna 8, a first high-precision clock, a second high-precision clock, and a third high-precision clock. The first antenna 1, the second antenna 4, and the third antenna 8 are evenly distributed at the three corners of the shell to form a distributed positioning tag. The distance between each antenna and the center of the shell is L. The positioning tag is used to receive the signal sent by the positioning base station.

[0048] A two-degree-of-freedom gyroscope is arranged on the shell and is used for measuring the horizontal deflection angle and the pitch deflection angle of the shell.

[0049] The Beidou satellite communication module includes: a Beidou communication antenna 6, which is embedded in the side wall of the shell. The standard synchronous clock in the Beidou satellite communication module is connected to the positioning tag through the serial port to achieve clock synchronization of the distributed positioning tag.

[0050] The display 3 is connected to the processor and is provided on the upper surface of the housing for displaying the horizontal deflection angle, the pitch deflection angle and the housing position coordinates for later correction.

[0051] The processor in the present invention is specifically an ARM embedded platform, which is connected to the positioning base station, positioning tag, depth measurement module 2, two-degree-of-freedom gyroscope and Beidou satellite communication module to calculate the position coordinates of the shell.

[0052] The power supply is connected to the embedded platform and other modules through wires. The present invention uses a power module that supports wireless charging, and no longer installs a charging socket on the mold, which maximizes the safety of the present invention. The present invention adds a power LED indicator 5, which lights up red when charging and lights up green when fully charged.

[0053] Based on the above system in the present invention, the present invention also proposes an underwater positioning method based on distributed positioning tags for calculating the position coordinates of the shell, which specifically includes the following steps:

[0054] S1: Use the depth measurement module 2 to measure the depth H of the housing underwater.

[0055] S2: Measure the height h of the positioning base station from the water surface.

[0056] S3: Based on the depth H of the housing underwater and the height h of the positioning base station from the water surface, obtain the height z of the housing from the positioning base station; z=.

[0057] S4: A two-degree-of-freedom gyroscope is used to measure the horizontal deflection angle and the pitch deflection angle of the shell. Figure 2 It can be seen that α∈[0,2π), β∈[0,π].

[0058] S5: For ease of calculation, assume that the shell position coordinates are (x, y, z); construct a coordinate system with the mold position center as the origin. According to the geometric shape of the positioning tag distribution, the relative coordinate value of the positioning tag in this coordinate system can be known; according to the horizontal deflection angle and pitch deflection angle, as well as the geometric relationship between the first antenna, the second antenna, and the third antenna, the actual coordinate value of the positioning tag can be obtained using the coordinate system conversion principle, that is:

[0059]

[0060] in, They represent the actual coordinate values ​​of the first antenna 1, the second antenna 4 and the third antenna 8 respectively, L is the distance between the first antenna 1, the second antenna 4 and the third antenna 8 and the center of the shell, α is the horizontal deflection angle, β is the pitch deflection angle, and z is the height of the shell from the positioning base station.

[0061] S6: Obtain the timestamps when the first antenna 1 , the second antenna 4 , and the third antenna 8 in the positioning tag receive the signal sent by the positioning base station.

[0062] S7: Calculate the position coordinates of the housing based on the timestamp and the coordinate values ​​of the first antenna 1 , the second antenna 4 and the third antenna 8 .

[0063] That is, according to the geometric relationship between the timestamp and the first antenna 1 , the second antenna 4 and the third antenna 8 , the position coordinates of the housing can be obtained by using an algebraic analysis method.

[0064] The positioning tag records the timestamp when receiving the positioning base station signal with the same tag, and then a set of equations with constraints can be constructed, namely:

[0065]

[0066] Wherein, t1, t2, and t3 represent the timestamps corresponding to the signals received by the first antenna 1, the second antenna 4, and the third antenna 8, respectively, and c is the speed of light. By solving the equations by algebraic operation, the position coordinates (x, y, z) of the shell can be obtained.

[0067] The method described above in the present invention first uses a depth measurement module 2 to determine the mold's depth. It then uses a two-degree-of-freedom gyroscope to record the unit's horizontal and pitch angles. Distributed UWB ultra-wideband positioning tags are then used to determine the relative time difference of arrival. By algebraically solving a constrained system of single-curve equations, the position coordinates of the underwater target are obtained. The present invention not only prints the relevant parameters and results on a liquid crystal display 3 for later calibration, but also transmits the position coordinates to a master control terminal via a Beidou satellite communication system module. The present invention boasts a simple structure and easy operation. It can be attached or placed on an underwater target, making it adaptable to various underwater environments.

[0068] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0069] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. An underwater positioning system based on distributed positioning tags, characterized in that: The positioning system comprises: The positioning base station is set up at a fixed location on the shore or on the ship and is used to periodically transmit signals outward; a housing, wherein the upper surface of the housing is triangular; A positioning tag is provided on the housing and is used to receive signals sent by the positioning base station; the positioning tag includes: a first antenna, a second antenna, a third antenna, a first high-precision clock, a second high-precision clock, and a third high-precision clock, wherein the first antenna, the second antenna, and the third antenna are evenly distributed at three corners of the housing; a depth measurement module, disposed on the housing and configured to measure the depth of the housing underwater; A two-degree-of-freedom gyroscope is provided on the housing and is used to measure the horizontal deflection angle and the pitch deflection angle of the housing; Beidou satellite communication module, including Beidou communication antenna, for clock synchronization; The processor is connected to the positioning base station, the positioning tag, the depth measurement module, the two-degree-of-freedom gyroscope, and the Beidou satellite communication module, and is used to calculate the position coordinates of the shell, specifically including: using the depth measurement module to obtain the depth of the shell, combining the horizontal deflection angle and the pitch deflection angle of the shell measured by the two-degree-of-freedom gyroscope, using the distributed UWB ultra-wideband positioning tag to obtain the relative time arrival difference, and algebraically solving the constrained single curve equation group to obtain the position coordinates of the underwater target.

2. The underwater positioning system based on distributed positioning tags according to claim 1, characterized in that: The positioning base station includes: a fourth antenna and a fourth high-precision clock.

3. The underwater positioning system based on distributed positioning tags according to claim 1, characterized in that: The positioning system further includes a display connected to the processor and configured to display the horizontal deflection angle, the pitch deflection angle, and the position coordinates of the housing.

4. The underwater positioning system based on distributed positioning tags according to claim 1, characterized in that: The positioning system further includes: a power supply, an LED indicator light and a waterproof switch, which are arranged on the housing.

5. An underwater positioning method for distributed positioning tags, characterized in that: The positioning method includes: A depth measurement module is used to measure the depth H of the shell under water; Measure the height h of the positioning base station from the water surface; The height z of the housing from the positioning base station is obtained based on the depth H of the housing underwater and the height h of the positioning base station from the water surface; z=H+h; A two-degree-of-freedom gyroscope is used to measure the horizontal deflection angle and the pitch deflection angle of the shell; Let the coordinates of the shell be (x, y, z); The coordinate values ​​of the first antenna, the second antenna, and the third antenna in the positioning tag are calculated based on the horizontal deflection angle and the pitch deflection angle; wherein the positioning tag is provided on the housing and is used to receive the signal sent by the positioning base station; the positioning tag includes: a first antenna, a second antenna, a third antenna, a first high-precision clock, a second high-precision clock, and a third high-precision clock, and the first antenna, the second antenna, and the third antenna are evenly distributed at the three corners of the housing; Obtaining the timestamps when the first antenna, the second antenna, and the third antenna in the positioning tag receive the signal sent by the positioning base station; The position coordinates of the housing are calculated based on the time stamp and the coordinate values ​​of the first antenna, the second antenna, and the third antenna.

6. The underwater positioning method of distributed positioning tags according to claim 5, characterized in that: The coordinate values ​​of the first antenna, the second antenna, and the third antenna in the positioning tag are calculated according to the horizontal deflection angle and the pitch deflection angle using the following formula: in, Represent the actual coordinate values ​​of the first antenna, the second antenna and the third antenna respectively, L is the distance between the first antenna, the second antenna and the third antenna and the center of the shell, α is the horizontal deflection angle, β is the pitch deflection angle, and z is the height of the shell from the positioning base station.

7. The underwater positioning method of distributed positioning tags according to claim 6, characterized in that: The position coordinates of the housing are calculated based on the timestamp and the coordinate values ​​of the first antenna, the second antenna, and the third antenna, that is, the following formula is used to solve: Wherein, t1, t2, and t3 represent the timestamps corresponding to the signals received by the first antenna, the second antenna, and the third antenna, respectively, and c is the speed of light.

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