Single-beam sonar-based high-low speed adaptive height measurement method and system for underwater vehicle

Abstract

The application discloses a kind of based on single-beam sonar's submarine high-low speed adaptive height measurement method and system, belong to underwater detection and submarine navigation technical field.Method includes:S1, the navigation and attitude information of submarine is acquired in real time;S2, the current speed is compared with preset speed threshold, and the height measurement mode of sonar beam is decided;S3, according to the height measurement mode of decision, the beam emission direction of single-beam sonar transducer is adjusted;S4, and the height value is calculated using corresponding height solving algorithm, and the target height value is output in combination with Kalman filtering fusion technology;S5, when height measurement mode switches, using hysteresis algorithm and smooth interpolation technique, so that target height value output continuous no jump.This application provides based on single-beam sonar's submarine high-low speed adaptive height measurement method and system realize submarine high-low speed under high-precision, no jump adaptive height measurement from bottom, improve underwater navigation precision and stability.

Description

Technical Field

[0001] This invention belongs to the field of underwater detection and submersible navigation technology, and particularly relates to an adaptive altitude measurement method and system for submersibles based on single-beam sonar at high and low speeds. Background Technology

[0002] Single-beam sonar altimeters are key sensors for underwater navigation, obstacle avoidance, and terrain following in submersibles. Their basic principle is to calculate the altitude above the seabed by measuring the time it takes for a sound wave to travel to and from the seabed. However, existing technologies have several inherent limitations:

[0003] One issue is the lag problem in high-speed measurements, also known as the "dragging effect." (See attached image.) Figure 1 As shown, during high-speed navigation, the underwater vehicle has moved forward a certain distance between the time the sound waves are transmitted and received. This results in the received echo information corresponding to the terrain at a lagging position, rather than the terrain directly below it. This causes a mismatch between measurement data and navigation data, distorts the terrain map, and fails to accurately reflect the underwater vehicle's current altitude, posing a significant risk to safe navigation.

[0004] Second, there is the issue of attitude sensitivity. Submarines experience pitch and roll during navigation. Although existing technologies compensate for these using attitude sensors, the measurement accuracy drops significantly at large pitch angles, and the beam illumination area deviates severely from directly below, rendering the measurements unrepresentative.

[0005] Third, there is a contradiction between high and low speed performance. At low speeds, vertically downward beams can achieve the best accuracy, but at high speeds, the effectiveness of vertical beams is greatly reduced due to lag. Existing fixed-beam solutions cannot meet both operating conditions.

[0006] Fourth, there is a conflict between cost and performance. While forward-looking multibeam sonar can solve the problem of forward perception, it is expensive, has complex data processing, and consumes a lot of power, making it unsuitable for low-cost, miniaturized underwater vehicle platforms.

[0007] In recent years, dynamic beam control technology, multi-sensor fusion technology and adaptive algorithm technology have become development trends. However, there is currently no technology that can achieve adaptive and accurate altimetry measurement of single-beam sonar in the range of high and low flight speeds. Therefore, there is an urgent need for a solution that takes into account high precision, wide adaptability and low cost. Summary of the Invention

[0008] In view of the shortcomings of the related technologies, the purpose of this invention is to provide an adaptive altimeter measurement method and system for underwater vehicles based on single-beam sonar, so as to solve the problems mentioned in the background technology.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] An adaptive altimeter measurement method for underwater vehicles based on single-beam sonar, comprising the following steps:

[0011] S1. Acquire navigation and attitude information of the underwater vehicle in real time, including speed, heading, pitch angle, roll angle and depth value;

[0012] S2. Compare the current speed with the preset speed threshold to determine the altimeter mode of the sonar beam. The altimeter modes include low-speed vertical mode and high-speed forward tilt mode.

[0013] S3. Adjust the beam emission direction of the single-beam sonar transducer according to the determined altimeter mode;

[0014] S4. Based on the determined altimetry mode, calculate the height value using the corresponding height calculation algorithm, and output the target height value by combining it with Kalman filter fusion technology.

[0015] S5. When switching between height measurement modes, a hysteresis algorithm and smooth interpolation technique are used to ensure that the target height value output is continuous and without jumps.

[0016] In some embodiments, in step S2, the preset speed threshold includes a first speed threshold. Second speed threshold ,and Let the speed of the underwater vehicle be... ;when At that time, the decision-making altimeter operation mode is low-speed vertical mode; when At that time, the decision-making altimeter working mode is the high-speed forward tilt mode; when At that time, the decision-making altimeter working mode is the high-speed forward tilt mode.

[0017] In some embodiments, in step S3, in low-speed vertical mode, the beam transmission direction is adjusted to vertically downward transmission, at which time the beam forward tilt angle is... For fixed values, ;

[0018] In high-speed forward tilt mode, adjust the beam transmission direction to be slightly downward and forward along the submarine's heading, and adjust the beam forward tilt angle accordingly. At this point, the beam tilt angle is... The beam tilt angle is a dynamically calculated value. The calculation formula is:

[0019]

[0020] in, As a correction factor, when hour, Take 1.2, when hour, Take 1.25, For the speed of the underwater vehicle, For the theoretical round-trip time of the sound wave, This is an estimate of the height from the previous cycle.

[0021] In some embodiments, in step S4, when the height measurement working mode is low-speed vertical mode, the height value is calculated using the following formula:

[0022]

[0023]

[0024] in, The altitude of the underwater vehicle, This is the slant distance between the single-beam sonar transducer and the seabed detection point. The pitch angle is the angle of inclination. This is the roll angle. The speed of sound in water, This represents the actual round-trip time of the sound wave.

[0025] In some embodiments, in step S4, when the height measurement working mode is high-speed forward tilt mode, the height value is calculated using the following steps:

[0026] S401. Calculate the slant distance between the single-beam sonar transducer and the seabed detection point based on the measured round-trip time of the sound wave.

[0027] S402. Calculate the attitude compensation coefficient based on the submarine's pitch and roll angles.

[0028] S403. Calculate the temporary vertical height without considering motion compensation by combining the beam tilt angle, slant range and attitude compensation coefficient.

[0029] S404. Obtain the vertical velocity of the submersible, calculate the vertical displacement during the measured round-trip time of the sound wave, correct the temporary vertical height based on the vertical displacement, and obtain the actual measured height value for the current period.

[0030] In some embodiments, in step S4, the Kalman filter fusion technique includes:

[0031] Define the state vector:

[0032]

[0033] in, The altitude of the underwater vehicle, Vertical velocity, The pitch angle is the angle of inclination. This refers to the roll angle;

[0034] Based on the state vector of the previous cycle, predict the height of the current cycle. ;

[0035] Construct the observation equation:

[0036]

[0037] in, This is the height value calculated in the current cycle. To observe noise;

[0038] Calculate Kalman gain And combined with height prediction values Combined with the observation residuals, output the fused target height value. .

[0039] In some embodiments, in step S5, the hysteresis algorithm involves setting a switching threshold. and ,and When the speed At that time, switch to high-speed forward tilt mode, when the speed When switching to low-speed vertical mode, an exponential smoothing algorithm is used to adjust the beam tilt angle during mode switching. For interpolation, the smooth interpolation formula is:

[0040]

[0041] in, For sampling period index, For the first The optimal forward tilt angle of the cycle, For the first The forward tilt angle of the cycle, For smoothing coefficients, .

[0042] An adaptive altimeter system for underwater vehicles based on single-beam sonar, applied to the aforementioned adaptive altimeter method for underwater vehicles based on single-beam sonar, includes:

[0043] A single-beam sonar transducer is installed on a submersible and is used to transmit and receive acoustic signals.

[0044] The rotating mechanism is connected to the single-beam sonar transducer and is used to adjust the emission direction of the sonar beam.

[0045] The sensor unit is used to collect the navigation and attitude information of the underwater vehicle in real time. The navigation and attitude information includes speed, heading, pitch angle, roll angle and depth value.

[0046] The navigation control module is communicatively connected to the rotation mechanism and the sensor unit. The navigation control module is used to receive information collected by the sensor unit, decide the altimeter operation mode of the sonar beam, generate beam transmission direction control commands, and calculate the altitude of the submersible.

[0047] In some embodiments, the rotating mechanism is a waterproof servo motor with a rotation range of ±20° and a rotation accuracy of ±0.01°. The waterproof servo motor is connected to the single-beam sonar transducer through a gear transmission mechanism.

[0048] In some embodiments, the sensor unit includes a Doppler velocimeter, an inertial measurement unit, and a pressure sensor; the Doppler velocimeter is used to measure airspeed with an accuracy of [insert accuracy here]. The inertial measurement unit is used to measure the pitch, roll, and yaw angles with an accuracy of [insert accuracy here]. The pressure sensor is used to collect water pressure data and calculate the depth value based on the water pressure data. The depth calculation accuracy is [insert accuracy here]. .

[0049] Compared with the prior art, the beneficial effects of the present invention are:

[0050] 1. The adaptive altimeter measurement method for underwater vehicles based on single-beam sonar, which is designed for high and low speed scenarios of underwater vehicles, achieves high-precision altitude measurement by integrating adaptive mode switching, attitude / motion compensation and Kalman filtering. At the same time, it adopts hysteresis algorithm and smooth interpolation technology to ensure that the altitude output is continuous and without jumps during mode switching, effectively solving the problems of beam illumination point offset and large measurement error under high speed navigation, and significantly improving the accuracy and reliability of underwater navigation and detection.

[0051] 2. The underwater vehicle high and low speed adaptive altimeter system provided by this invention, through the collaboration of a single-beam sonar transducer, a waterproof servo motor and multiple sensor units, and the adaptive algorithm of the navigation control module, can achieve high-precision, continuous and non-jumping altitude measurement of the underwater vehicle at high and low speeds. It has a compact structure, is suitable for the underwater environment, and can effectively compensate for attitude and motion errors, providing stable and reliable altitude data support for underwater navigation, obstacle avoidance and detection of the underwater vehicle. Attached Figure Description

[0052] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0053] Figure 1 This is a schematic diagram illustrating the measurement hysteresis problem of single-beam sonar at high speeds in existing technologies.

[0054] Figure 2This is a flowchart of an embodiment of the adaptive altimeter measurement method and system for underwater vehicles based on single-beam sonar of the present invention.

[0055] Figure 3 This is a system structure principle block diagram of an embodiment of the adaptive altimeter measurement method and system for underwater vehicles based on single-beam sonar of the present invention;

[0056] Figure 4 This is a schematic diagram illustrating the working principle of a high-speed forward tilt mode in an embodiment of the adaptive altitude measurement method and system for underwater vehicles based on single-beam sonar of the present invention.

[0057] In the picture:

[0058] 1. Submarine vehicle; 2. Single-beam sonar transducer; 3. Rotation mechanism; 4. Sensor unit; 41. Doppler velocimeter; 42. Pressure sensor; 43. Inertial measurement unit; 5. Navigation control module; 51. Altitude data calculation unit; 52. Submarine navigation control unit. Detailed Implementation

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0060] In the description of this invention, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0061] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0062] Example 1:

[0063] See appendix Figures 2 to 4This paper presents a schematic embodiment of the adaptive altimeter measurement method for underwater vehicles (UVs) based on single-beam sonar at different speeds proposed in this invention. This method is applicable to accurate altitude measurement of underwater vehicles (including AUVs, ROVs, etc.) at different speeds. See appendix. Figure 2 The adaptive altimeter measurement method for high and low speeds of a submersible based on a single-beam sonar includes the following steps:

[0064] S1. Acquire real-time navigation and attitude information of the submersible 1, including speed. Heading and pitch angle Roll angle and depth value ;

[0065] S2, Change current speed The sonar beam's height measurement mode is determined by comparing it with a preset speed threshold. The height measurement modes include low-speed vertical mode and high-speed forward tilt mode.

[0066] S3. Based on the determined height measurement working mode, adjust the beam emission direction of the single-beam sonar transducer 2.

[0067] S4. Based on the determined altimetry mode, calculate the height value using the corresponding height calculation algorithm, and output the target height value by combining it with Kalman filter fusion technology.

[0068] S5. When switching between height measurement modes, a hysteresis algorithm and smooth interpolation technique are used to ensure that the target height value output is continuous and without jumps.

[0069] In step S2, the preset speed threshold includes a first speed threshold. Second speed threshold ,and Let the speed of submersible 1 be... ;when At this time, the decision-making altimeter operates in low-speed vertical mode. In low-speed vertical mode, the control beam is emitted vertically downwards, suitable for hovering and low-speed cruising, to achieve the highest vertical measurement accuracy. At that time, the decision-making altimeter working mode is the high-speed forward tilt mode; when At that time, the decision-making altimeter mode is the high-speed forward tilt mode; in the high-speed forward tilt mode, based on the ship's speed... and current height estimate Calculate a forward tilt launch angle Control the beam at this angle Launch forward and downward towards submarine 1. It should be noted that only the first speed threshold is applied. The second speed threshold is used to measure the switching threshold of the working mode. It is not used for mode switching, but for distinguishing high-speed ranges to select the corresponding beam tilt correction coefficient.

[0070] In step S3, in low-speed vertical mode, the beam transmission direction is adjusted to vertically downward. At this time, the beam forward tilt angle is... For fixed values, ;

[0071] See appendix Figure 4 In high-speed forward tilt mode, the beam transmission direction is adjusted to be slightly downward and forward along the heading of the submersible 1, and the beam tilt angle is adjusted accordingly. At this point, the beam tilt angle is... The beam tilt angle is a dynamically calculated value. The calculation formula is:

[0072]

[0073] in, As a correction factor, when hour, Take 1.2, when hour, Take 1.25, The speed of submersible 1 For the theoretical round-trip time of the sound wave, This is an estimate of the height from the previous cycle.

[0074] In step S4, when the altimeter mode is low-speed vertical mode, the beam is emitted vertically downwards, and the measured slant range is... Approximately equal to the vertical height, and considering the attitude influence of submersible 1, attitude compensation is performed, and the altitude value is calculated using the following formula:

[0075]

[0076]

[0077] in, The altitude of submersible 1 This is the slant distance between the single-beam sonar transducer 2 and the seabed detection point. The pitch angle is the angle of inclination. This is the roll angle. The speed of sound in water, This represents the actual round-trip time of the sound wave.

[0078] In step S4, when the altimeter is in high-speed forward tilt mode, the forward tilt angle of the beam and the attitude of the submersible 1 need to be considered. The vertical height is calculated through three-dimensional geometric transformation, and the altitude value is obtained by the following steps:

[0079] S401. Calculate the slant distance between the single-beam sonar transducer 2 and the seabed detection point based on the measured round-trip time of the sound wave.

[0080] S402. Calculate the attitude compensation coefficient based on the pitch and roll angles of the submersible 1.

[0081] S403. Calculate the temporary vertical height without considering motion compensation by combining the beam tilt angle, slant range and attitude compensation coefficient.

[0082] S404. Obtain the vertical velocity of the submersible 1, calculate the vertical displacement during the measured round-trip time of the sound wave, correct the temporary vertical height based on the vertical displacement, and obtain the actual measured height value for the current cycle.

[0083] In step S4, to improve measurement accuracy and smooth the data, an extended Kalman filter (EKF) is used to fuse the measured and predicted values. The Kalman filter fusion technique includes:

[0084] Define the state vector:

[0085]

[0086] in, The altitude of submersible 1 Vertical velocity, The pitch angle is the angle of inclination. This refers to the roll angle;

[0087] Based on the state vector of the previous cycle, predict the height of the current cycle. ;

[0088] Construct the observation equation:

[0089]

[0090] in, This is the height value calculated in the current cycle. To observe noise;

[0091] Calculate Kalman gain And combined with height prediction values Combined with the observation residuals, output the fused target height value. That is, the optimal estimated height, with an error controlled within ±3cm.

[0092] In step S5, during the switching of the height measurement working mode (such as... exist When there are fluctuations in the vicinity, a hysteresis algorithm is used to prevent frequent mode jumps, and the beam tilt angle is adjusted. Perform smooth interpolation to ensure continuous height output without jumps.

[0093] The hysteresis algorithm is as follows: set a switching threshold. and ,and In this embodiment, =3.5 sections, =2.5 knots. At speed At that time, switch to high-speed forward tilt mode, when the speed When switching to low-speed vertical mode, an exponential smoothing algorithm is used to adjust the beam tilt angle during mode switching. To ensure the continuity of the height output, interpolation is performed. The smooth interpolation formula is as follows:

[0094]

[0095] in, For sampling period index, For the first The optimal forward tilt angle of the cycle, For the first The forward tilt angle of the cycle, For smoothing coefficients, The value is generally taken as 0.3 based on the experimental results.

[0096] In this embodiment, the dynamic beam control algorithm is the core, and its implementation steps are described below:

[0097] (1) Parameter initialization: When the system starts, the speed threshold is initialized. =3 sections (1.54m / s), =6 sections (3.09 m / s). These thresholds were determined based on a large amount of experimental data, balancing the requirements of measurement accuracy and real-time performance.

[0098] (2) Motion state perception: The real-time speed V of the submersible 1 is measured by DVL, and the pitch angle is measured by IMU. and roll angle Depth D is measured using pressure sensor 42. All sensor data is acquired and updated at a frequency of 100Hz.

[0099] (3) Mode Decision: Based on the comparison between the current speed V and the preset threshold, the working mode is determined:

[0100] when At this time, it enters low-speed vertical mode, and the beam is emitted vertically downward (α=0°).

[0101] when At that time, enter high-speed forward tilt mode and calculate the beam forward tilt angle α. ≈1.2.

[0102] when At that time, enter high-speed forward tilt mode and calculate the beam forward tilt angle α. ≈1.25.

[0103] (4) Beam tilt angle calculation: In high-speed tilt mode, the beam tilt angle α is calculated according to the following formula:

[0104]

[0105] in, At the current speed, The round-trip time of the sound wave ( , Let the speed of sound in water be taken as... ), This is an estimate of the height from the previous cycle.

[0106] To compensate for the effects of high-speed motion and acceleration, a correction factor is introduced. (Usually, 1.2 is used for sections 3-6, and 1.25 is used for sections 6-35, calibrated experimentally). The corrected formula is:

[0107]

[0108] (5) Beam control: based on the calculated forward tilt angle The sonar transducer is rotated to the corresponding position via a servo motor. The control process employs closed-loop feedback, with the current angle monitored in real time by the servo motor's built-in angle encoder to ensure angle control accuracy.

[0109] In the above illustrative embodiment, the high and low speed adaptive altimeter method for the submersible 1 based on single-beam sonar can adapt to a wide range of speed changes of the submersible 1 from low speed to high speed, and achieve accurate and continuous altitude measurement above the bottom, specifically including:

[0110] Improved high-speed measurement performance: Through dynamic beam tilt control, the measurement lag problem during high-speed navigation of the submersible 1 was effectively solved, significantly improving the real-time performance and accuracy of altitude measurement.

[0111] Enhanced attitude adaptability: Through attitude compensation algorithms, the system’s adaptability to attitude changes such as pitch and roll of the submersible has been greatly improved, ensuring that high measurement accuracy can still be maintained under large tilt conditions.

[0112] Expanding the effective working range: By adaptively switching between high and low speed modes, the system takes into account both the high-precision measurement requirements during low-speed navigation and the real-time requirements during high-speed navigation, effectively expanding the working speed range and application scenarios of the single-beam sonar altimeter.

[0113] Optimize system cost and size: Adaptive altimetry is achieved based on a single-beam architecture, eliminating the need for complex hardware such as multi-beam arrays, which significantly reduces system cost and complexity, making it more suitable for the low-cost, miniaturized Submarine-1 platform.

[0114] Example 2:

[0115] See appendix Figures 2 to 4 This paper presents an illustrative embodiment of the adaptive altimeter system for high and low speeds of a submersible 1 based on a single-beam sonar proposed in this invention, applied to the adaptive altimeter method for high and low speeds of a submersible 1 based on a single-beam sonar in Embodiment 1. See Appendix. Figure 3 and Figure 4 The high and low speed adaptive altimeter system of the submersible 1 based on single-beam sonar includes a single-beam sonar transducer 2, a rotating mechanism 3, a sensor unit 4, and a navigation control module 5.

[0116] A single-beam sonar transducer 2 is mounted on the submersible 1. The single-beam sonar transducer 2 is used to transmit and receive acoustic signals. In this embodiment, the single-beam sonar transducer 2 is a 200kHz high-frequency transducer with a beamwidth of [missing information]. The maximum measurement distance is 500 meters, and the transducer is integrated into a waterproof housing that can withstand the pressure of water up to 1,000 meters deep.

[0117] The rotating mechanism 3 is a servo mechanism capable of one-dimensional or two-dimensional rotation, used to precisely control the transmission direction of the sonar beam. By rotating mechanism 3, the beam automatically tilts forward at a corresponding angle according to the vehicle speed, allowing the acoustic illumination point to "predict" the position of the submersible 1 when the acoustic wave returns, thus compensating for the lag of the echo information behind the current position. The rotating mechanism 3 is connected to the single-beam sonar transducer 2; the rotating mechanism 3 is a waterproof servo motor with a rotation range of ±20° and a rotation accuracy of ±0.01°. The waterproof servo motor is connected to the single-beam sonar transducer 2 via a gear transmission mechanism to ensure precise control of the beam direction.

[0118] Sensor unit 4 is used to collect navigation and attitude information of the submersible 1 in real time. This navigation and attitude information includes speed, heading, pitch angle, roll angle, and depth. In this embodiment, sensor unit 4 includes a Doppler velocimeter 41 (DVL), an inertial measurement unit 43 (IMU), and a pressure sensor 42. The Doppler velocimeter 41 is used to measure speed with an accuracy of [insert accuracy here]. The inertial measurement unit 43 is used to measure attitude angles, including pitch angle. Roll angle and heading angle The accuracy is Pressure sensor 42 is used to collect water pressure data and calculate the depth value based on the water pressure data. The depth calculation accuracy is [insert accuracy here]. .

[0119] The navigation control module 5 is communicatively connected to the rotation mechanism 3 and the sensor unit 4. The navigation control module 5 receives information collected by the sensor unit 4, determines the altimeter mode of the sonar beam, generates beam transmission direction control commands, and calculates the altitude of the submersible 1. In this embodiment, the navigation control module 5 uses an STM32H743 microcontroller as its core processor, with a main frequency of 480MHz and abundant interface resources. The processor integrates a DVL interface (RS232), an IMU interface (I2C), a pressure sensor 42 interface (RS485), and a servo control interface (PWM). Two software units, the altitude data calculation unit 51 and the submersible navigation control unit 52, are embedded and run within the navigation control module 5. The altitude data calculation unit 51 and the submersible navigation control unit 52 interact via a communication interface. In other words, the navigation control module 5 runs software including the submersible navigation control unit 52 and the altitude data calculation unit 51, and also includes a navigation interface, an attitude sensor interface, and a data processing module. The altitude data calculation unit 51 is used to receive sensor data, decide on the working mode, calculate control commands, and calculate the final altitude.

[0120] In this embodiment, the high / low speed adaptive altimeter system for the submersible 1 based on a single-beam sonar also includes a power supply module. The system uses DC 24V power and provides the required operating voltage to each module through a DC-DC converter. This module is used for data exchange with the navigation and control system of the submersible 1.

[0121] In the above illustrative embodiment, the high and low speed adaptive altimeter system for the submersible 1 based on a single-beam sonar, by adjusting the sonar beam emission direction in real time, adaptively switches between vertical look-down mode and forward tilt prediction mode, fundamentally solving the measurement lag problem when the submersible 1 is traveling at high speed. Specifically, it includes:

[0122] Adaptive speed capability: By sensing the motion state of the submersible 1 in real time and combining it with the high-precision rotating mechanism 3 to achieve dynamic beam control, the beam direction can be flexibly adjusted according to changes in speed, effectively covering a wide range of working scenarios from low speed to high speed.

[0123] Improved real-time performance of high-speed measurements: Based on the motion model of the submersible 1 and the prediction illumination point algorithm for altitude estimation, the optimal beam tilt angle can be accurately calculated, so that the acoustic illumination point coincides with the expected position of the submersible 1 during the acoustic round-trip time, which significantly improves the measurement lag during high-speed navigation and enhances the real-time performance and accuracy of altitude measurement.

[0124] Enhanced measurement accuracy and reliability: Matched height calculation algorithms are adopted for different working modes, and combined with multi-mode data fusion technology such as Kalman filtering, so that stable and high-precision height results can still be output under attitude changes and motion disturbances, thereby improving the overall reliability of the system.

[0125] Smooth and stable mode switching: An adaptive switching strategy is constructed by using hysteresis algorithm and smooth interpolation technology to avoid frequent mode jitter near the airspeed threshold, ensuring continuous and uninterrupted altitude output during mode switching and guaranteeing the stability of altimetry data.

[0126] Example 3:

[0127] This embodiment exemplifies the specific implementation of the adaptive altimeter measurement method for submersible 1 based on single-beam sonar in low-speed vertical mode.

[0128] At a shallow depth of 10 meters, when the submersible 1 is cruising at a speed of 2 knots (approximately 1.03 m / s) in shallow coastal waters, the system operates in low-speed vertical mode.

[0129] Known parameters include: speed (Section 2) Low-speed threshold Festival Slope distance measurement value Pitch angle Roll angle Optimal height of the previous cycle Vertical velocity Filtering period Speed ​​of sound .

[0130] The mathematical calculation process is as follows:

[0131] (1) First, determine the speed. Determined to be low speed, maintain vertical mode ( ).

[0132] (2) Then, attitude compensation calculation is performed. The attitude compensation coefficient is based on trigonometric function relationships to correct the influence of hull tilt on height measurement:

[0133]

[0134]

[0135]

[0136] Then calculate the vertical height:

[0137]

[0138] (3) Next, Kalman filtering fusion is performed:

[0139] 1) Predicted value (based on the state of the previous cycle):

[0140]

[0141] 2) Observation noise covariance Process noise covariance

[0142] 3) Kalman gain

[0143] 4) Optimal height output:

[0144]

[0145] Optimal height With an error of ≤±0.005m, it meets the high-precision measurement requirements of nearshore shallow seas.

[0146] Example 4:

[0147] This embodiment exemplifies the specific implementation of the high / low speed adaptive altimeter measurement method for a submersible based on a single-beam sonar in high-speed forward tilt mode proposed in this invention. (See attached diagram.) Figure 4 This is a schematic diagram of the working principle in the high-speed forward tilt mode of this embodiment. In this diagram, L=V×Δt is the horizontal displacement of the submersible 1 during the round-trip propagation time of the sound wave, V is the real-time speed of the submersible, and Δt is the round-trip propagation time of the sound wave in the water. Through adaptive control of the beam forward tilt angle, the position of the predicted illumination point of the sound wave is matched with the position of the submersible echo reception time, thereby compensating for the measurement lag error caused by high-speed navigation.

[0148] At a shallow depth of 10 meters, when submersible 1 is traveling at a near-shore ultra-high speed of 35 knots (approximately 18.00 m / s), the system operates in high-speed forward tilt mode. The mathematical calculation process is as follows:

[0149] Known parameters include: speed (35 sections), high-speed threshold Festival Optimal height of the previous cycle Vertical velocity (Upward movement), pitch angle Roll angle Speed ​​of sound Correction coefficient Filtering period .

[0150] The mathematical calculation process is as follows:

[0151] (1) First, determine the speed. The speed was determined to be ultra-high, and the forward tilt mode was activated.

[0152] (2) First calculate the beam tilt angle:

[0153] 1) Sound wave round-trip time estimation (based on the height of the previous cycle):

[0154]

[0155] 2) Horizontal movement distance at ultra-high speed:

[0156]

[0157] 3) Basic lean angle (geometric aiming model):

[0158]

[0159] 4) Correcting the lean angle (compensating for inertia error):

[0160]

[0161] (3) Perform slope distance measurement and height calculation:

[0162] 1) Measured round-trip time of sound waves (Shallow depth + surfacing results in a longer path), Slope distance:

[0163]

[0164] 2) Attitude compensation coefficient:

[0165]

[0166]

[0167]

[0168] 3) Vertical height (without considering motion compensation):

[0169]

[0170]

[0171]

[0172] (4) Calculation of motion compensation:

[0173] 1) Upward displacement (uniform motion model):

[0174]

[0175] 2) Actual measured height (rising → farther from the bottom, additive correction):

[0176]

[0177] (5) Kalman filter fusion:

[0178] 1) State vector:

[0179] 2) Predicted value:

[0180]

[0181] 3) Observation residuals:

[0182]

[0183] 4) Process noise covariance Observation noise covariance

[0184] 5) Kalman gain:

[0185]

[0186] 6) Optimal height output:

[0187]

[0188] (6) Calculation of hysteresis inhibition effect:

[0189] 1) Beam horizontal projection distance:

[0190]

[0191] 2) Horizontal displacement of submersible 1 during the same period:

[0192]

[0193] 3) Effective lag distance:

[0194]

[0195] 4) Lag inhibition rate:

[0196]

[0197] Optimal height With an error of ≤±0.01m and a hysteresis suppression rate of 75%, the problem of sound wave loss during ultra-high-speed navigation at a shallow depth of 10 meters is completely solved.

[0198] Example 5:

[0199] This embodiment exemplifies the specific implementation of the adaptive altimeter measurement method for submersible 1 based on single-beam sonar proposed in this invention, which switches between low-speed vertical mode and high-speed forward tilt mode.

[0200] At a shallow depth of 10 meters, when the speed of submersible 1 fluctuates within the threshold range (2.5 knots to 3.5 knots), the system achieves millisecond-level smooth switching, as mathematically verified below:

[0201] Known parameters include:

[0202] 1) Threshold: Festival , Festival

[0203] 2) Switching transition time (Shallow depth, fast response)

[0204] 3) Initial height Vertical velocity

[0205] 4) Optimal lean angle in high-speed mode (Calculated based on a super high speed of 35 knots and a depth of 10 meters)

[0206] Mathematical calculation process:

[0207] (1) Accelerated switching (low speed → high speed):

[0208] 1) Speed ​​from The speed (1.54 m / s) increased to Section (1.85m / s), triggering switching:

[0209] 2) Linear transition of the lean angle: ( (For switching time) when hour, Transition slope:

[0210]

[0211] Altitude fluctuation calculation: The altitude change during the handover period consists of two parts: "vertical displacement" and "filter correction", which are combined with the filter weights. The change in height during the switching period Substitute the data: (9mm), ≤0.01m.

[0212] (2) Deceleration switching (high speed → low speed):

[0213] 1) Speed ​​from The speed of the section (1.54 m / s) decreased to Section (1.23m / s), triggering switching:

[0214] 2) Linear transition of the lean angle: when hour, The transition slope is consistent with that of the acceleration phase;

[0215] 3) Altitude fluctuation calculation: (5mm), ≤0.01m.

[0216] During the above mode switching process, the maximum altitude fluctuation is ≤0.01m with no jumps, which meets the requirements for high-precision navigation in nearshore shallow seas.

[0217] This invention achieves adaptive altimeter measurement using a single-beam sonar altimeter through dynamic beam control. At low speeds, it employs a vertical look-down mode to ensure high-precision measurement, while at high speeds, it switches to a forward-tilt prediction mode, actively advancing the measurement point to the front of the submersible 1, ensuring precise matching of measurement data with the current position. This fundamentally solves the measurement lag problem of traditional single-beam sonar at high speeds, significantly improving the real-time performance of terrain perception and navigation safety. This system's architecture balances low-speed high precision with high-speed real-time performance, effectively expanding the operating speed range of the single-beam altimeter. Furthermore, through attitude compensation algorithms and dynamic beam control, it maintains high-precision measurement under large attitude conditions of ±20° pitch and ±15° roll. Compared to expensive... This invention relates to a forward-looking multibeam sonar, which adds a controllable mechanism to the single-beam hardware, achieving near-forward-looking perception with only a limited increase in cost. It combines high cost-effectiveness with intelligent features, automatically reverting to the traditional working mode at low speeds to ensure backward compatibility. Combined with data fusion algorithms, it further improves measurement reliability and accuracy. The entire system consists of a single-beam sonar transducer 2, a beam control mechanism, a main control unit, and a multi-sensor module. It has advantages such as low cost, low power consumption, and strong adaptability, and can be adapted to the precise altitude measurement requirements of a submersible 1 with a speed range of 0-35 knots. While retaining the low-cost advantage of single-beam sonar, it achieves near-multibeam measurement performance, providing a high-performance navigation solution for small submersibles 1.

[0218] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0219] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for adaptive altimetry measurement of underwater vehicles based on single-beam sonar at varying altitudes and speeds, characterized in that... Includes the following steps: S1. Acquire the navigation and attitude information of the underwater vehicle in real time, including speed, heading, pitch angle, roll angle and depth value; S2. Compare the current speed with a preset speed threshold to determine the sonar beam's altitude measurement mode. The altitude measurement mode includes a low-speed vertical mode and a high-speed forward tilt mode. The preset speed threshold includes a first speed threshold. Second speed threshold ,and Let the speed of the underwater vehicle be... ;when At that time, the decision-making altimeter operation mode is low-speed vertical mode; when At that time, the decision-making altimeter working mode is the high-speed forward tilt mode; when At that time, the decision-making altimeter operation mode is the high-speed forward tilt mode; S3. Based on the determined altitude measurement mode, adjust the beam emission direction of the single-beam sonar transducer; specifically, in low-speed vertical mode, adjust the beam emission direction to emit vertically downwards, at which point the beam forward tilt angle... For fixed values, In high-speed forward tilt mode, the beam transmission direction is adjusted to be slightly downward and forward along the submarine's heading, with the beam tilt angle adjusted accordingly. At this point, the beam tilt angle is... The beam tilt angle is a dynamically calculated value. The calculation formula is: in, As a correction factor, when hour, Take 1.2, when hour, Take 1.25, For the speed of the underwater vehicle, For the theoretical round-trip time of the sound wave, This is an estimate of the height from the previous cycle; S4. Based on the determined altimeter mode, calculate the height value using the corresponding height calculation algorithm, and output the target height value using Kalman filtering fusion technology; wherein, when the altimeter mode is low-speed vertical mode, the height value is calculated using the following formula: in, The altitude of the underwater vehicle, This is the slant distance between the single-beam sonar transducer and the seabed detection point. The pitch angle is the angle of inclination. This is the roll angle. The speed of sound in water, This refers to the actual round-trip time of the sound wave. When the height measurement working mode is high-speed forward tilt mode, the height value is calculated using the following steps: S401. Calculate the slant distance between the single-beam sonar transducer and the seabed detection point based on the measured round-trip time of the sound wave. S402. Calculate the attitude compensation coefficient based on the submarine's pitch and roll angles. S403. Calculate the temporary vertical height without considering motion compensation by combining the beam tilt angle, slant range and attitude compensation coefficient. S404. Obtain the vertical velocity of the submersible, calculate the vertical displacement during the measured round-trip time of the sound wave, correct the temporary vertical height based on the vertical displacement, and obtain the actual measured height value for the current period. S5. When switching between height measurement modes, a hysteresis algorithm and smooth interpolation technique are used to ensure that the target height value is output continuously without jumps.

2. The adaptive altimeter measurement method for underwater vehicles based on single-beam sonar according to claim 1, characterized in that, In step S4, the Kalman filter fusion technique includes: Define the state vector: in, The altitude of the underwater vehicle, Vertical velocity, The pitch angle is the angle of inclination. This refers to the roll angle; Based on the state vector of the previous cycle, predict the height of the current cycle. ; Construct the observation equation: in, This is the height value calculated in the current cycle. To observe noise; Calculate Kalman gain And combined with height prediction values Combined with the observation residuals, output the fused target height value. .

3. The adaptive altimeter measurement method for underwater vehicles based on single-beam sonar according to claim 1, characterized in that, In step S5, the hysteresis algorithm involves setting a switching threshold. and ,and When the speed At that time, switch to high-speed forward tilt mode, when the speed When switching to low-speed vertical mode, an exponential smoothing algorithm is used to adjust the beam tilt angle during mode switching. For interpolation, the smooth interpolation formula is: in, For sampling period index, For the first The optimal forward tilt angle of the cycle, For the first The forward tilt angle of the cycle, For smoothing coefficients, .

4. A high / low speed adaptive altimeter system for underwater vehicles based on single-beam sonar, characterized in that, The system, applied to the adaptive altimeter measurement method for underwater vehicles based on single-beam sonar as described in any one of claims 1-3, comprises: A single-beam sonar transducer is mounted on a submersible and is used to transmit and receive acoustic signals. A rotating mechanism is connected to the single-beam sonar transducer and is used to adjust the emission direction of the sonar beam. The sensor unit is used to collect navigation and attitude information of the submersible in real time, including speed, heading, pitch angle, roll angle and depth value. The navigation control module is communicatively connected to the rotating mechanism and the sensor unit. The navigation control module is used to receive information collected by the sensor unit, decide the altimeter operation mode of the sonar beam, generate beam transmission direction control commands, and calculate the altitude of the submersible.

5. The underwater vehicle altitude and low speed adaptive altimeter system based on single-beam sonar according to claim 4, characterized in that, The rotating mechanism is a waterproof servo motor with a rotation range of ±20° and a rotation accuracy of ±0.01°. The waterproof servo motor is connected to the single-beam sonar transducer through a gear transmission mechanism.

6. The underwater vehicle altitude and low speed adaptive altimeter system based on single-beam sonar according to claim 4, characterized in that, The sensor unit includes a Doppler velocimeter, an inertial measurement unit, and a pressure sensor; the Doppler velocimeter is used to measure the ship's speed with an accuracy of [missing information]. The inertial measurement unit is used to measure the pitch angle, roll angle, and yaw angle with an accuracy of [insert accuracy here]. The pressure sensor is used to collect water pressure data and calculate the depth value based on the water pressure data. The depth calculation accuracy is [insert accuracy here]. .

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