Laser measurement system for clearance height of sailing ship

Abstract

The invention discloses a laser measurement system for the clearance height of a sailing ship, and relates to the field of laser measurement, and the system comprises the steps: dynamically transmitting a laser beam with adjustable frequency and density to the upper part of the ship through a laser transmitting module; the laser receiving module captures a reflection signal and converts the reflection signal into a digital signal; in combination with the real-time position and track provided by the dual-mode positioning module and the ship attitude data measured by the attitude sensing module in real time, the data processing module performs attitude compensation correction on the laser measurement value; the environment monitoring module provides environment parameters for laser propagation speed correction. The processing module integrates all data to calculate a real-time clearance height, the real-time clearance height is displayed by the display early warning module in real time, and a graded sound-light alarm is triggered when the height is lower than a preset safety threshold value; and all data are encrypted and then stored by the storage module. The system has the advantages that through cooperation of multiple modules, laser parameters can be flexibly adjusted, the attitude can be accurately positioned and sensed, environmental errors are corrected to calculate the clearance height, and the ship navigation safety is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser measurement, in particular to a laser measurement system for the clearance height of a sailing ship. BACKGROUND

[0002] In the field of water transportation, when a sailing ship passes through a restricted airspace such as a bridge, overhead cable, or ship lock, accurate measurement of the clearance height is a key link to ensure navigation safety. With the development of the shipping industry towards large-scale and high-speed, the tonnage and mast height of ships are increasing, and the precision and efficiency of clearance height measurement are becoming increasingly demanding. Under this background, a laser-based clearance height measurement system for sailing ships has emerged, providing reliable technical support for water transportation safety supervision and facilitating the safe and efficient development of the shipping industry.

[0003] Current clearance height measurement systems for ships on the market are based on image acquisition, such as measuring by high-definition camera photography. Although this method can achieve automatic measurement to some extent, it is severely restricted by imaging conditions. In the night, rain, or dim light environment, the image clarity decreases significantly, resulting in a sharp decrease in measurement accuracy. Moreover, this method is complex to install and adjust, requiring careful calibration of camera position and angle, consuming a large amount of manpower and resources, and having high costs. There is also a scheme using infrared laser sensors, whose light source is a point light source, and the light spot is easily diffused after propagation. Visible light laser sensors have the problem of alignment difficulty, and a 1° deviation of the emitter can result in a deviation of tens of centimeters in the light spot at a distance, and the power is difficult to balance, which can cause eye injury at high power or the light spot cannot be seen at low power. Although infrared laser sensors have little harm to the human eye, the light spot is diffused over a large area after long-distance propagation, with a diameter of more than 2 meters, which can cause crosstalk to the surrounding receivers, resulting in inaccurate detection results. In addition, some infrared laser sensor systems using light synchronization have a delay in the action time due to internal capacitance, making it difficult to determine the synchronization time, increasing the difficulty of adjustment, and to avoid the difficulty of capturing the emission time caused by the internal structure, the detection frequency must be reduced, which can easily miss critical information and cause measurement errors. SUMMARY

[0004] To improve the existing system, a laser measurement system for the clearance height of a sailing ship is provided, which can flexibly adjust laser parameters, accurately position and perceive posture, correct environmental errors to calculate clearance height, and also can encrypt data storage and hierarchical sound and light warning, greatly improving the safety and reliability of ship navigation.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is:

[0006] A laser measurement system for the clearance height of a sailing ship, comprising:

[0007] The laser emission module is used for emitting a plurality of laser beams to a measurement area above a sailing ship, and adjusting a laser emission frequency and a distribution density of the laser beams according to a sailing speed of the ship and a measurement accuracy requirement;

[0008] The laser receiving module is arranged correspondingly with the laser emission module, and is used for receiving laser reflection signals reflected by obstacles in the measurement area, and converting the received optical signals into electrical signals;

[0009] The positioning module is used for acquiring real-time geographic position information and a sailing track of the ship through a Beidou navigation system and a GPS navigation system in a dual-mode positioning manner;

[0010] The attitude sensing module is used for collecting attitude parameters of the ship in the sailing process, and capturing dynamic attitude changes of the ship in real time through a MEMS gyroscope and an acceleration sensor, and performing temperature drift compensation and zero offset correction on the measurement data;

[0011] The environment monitoring module is used for detecting relevant parameters of a sailing environment of the ship, including an environmental temperature, a humidity, a visibility and a wind speed and direction;

[0012] The data processing module is electrically connected with the laser receiving module, the positioning module, the attitude sensing module and the environment monitoring module, and is used for receiving data transmitted by the modules, and performing attitude compensation correction on laser measurement data, and calculating a clear height of the ship in combination with positioning data and environmental parameters;

[0013] The data storage module is electrically connected with the data processing module, and is used for storing clear height data of the ship calculated by the data processing module, original data collected by the modules and system operation logs, and performing encryption processing through an encryption algorithm;

[0014] The display and early warning module is electrically connected with the data processing module, and is used for displaying ship data in real time, and issuing a pre-warning signal through an audible and visual alarm when the calculated clear height of the ship is lower than a preset safety threshold.

[0015] Preferably, the laser emission module specifically comprises:

[0016] The laser generator is used as a source of laser emission, generates an initial laser beam with a wavelength between 532 nm and 1064 nm, and provides a basic light source for laser measurement;

[0017] The beam shaper is used for processing the initial laser beam generated by the laser generator, shaping the initial laser beam into a laser beam with high parallelism and uniform light spots, and reducing an influence of beam divergence on measurement accuracy;

[0018] Scanning drive device: The device is used to drive the shaped laser beam to move within the measurement area. By using one-dimensional or two-dimensional scanning, the scanning speed is adjusted according to the ship's sailing speed and measurement accuracy requirements to achieve full coverage detection of the measurement area.

[0019] Preferably, the laser receiving module specifically includes:

[0020] Photoelectric detection unit: The unit uses an avalanche photodiode to receive weak laser reflection signals reflected by obstacles and convert them into initial electrical signals;

[0021] Signal conditioning circuit unit: The unit amplifies the weak electrical signal output by the photoelectric detection unit and filters out environmental noise through a second-order active low-pass filter circuit to improve signal quality;

[0022] A / D Conversion Unit: The unit uses a 16-bit high-speed A / D converter to accurately convert the conditioned analog electrical signal into a digital signal.

[0023] Preferably, the positioning module specifically includes:

[0024] Dual-mode positioning unit: The unit receives satellite signals from the Beidou navigation system and the GPS navigation system to obtain the ship's real-time geographical location information and navigation trajectory. When the signal of one navigation system is weaker than a preset threshold, it automatically switches to the other system to obtain continuous positioning data.

[0025] Differential positioning module: The unit receives differential correction information sent by the differential base station and corrects the original positioning data obtained by the dual-mode positioning unit in real time.

[0026] Preferably, the attitude sensing module specifically includes:

[0027] MEMS gyroscope unit: The unit is used to collect angular motion information during ship navigation, capture the dynamic changes in roll angle, pitch angle and heading angle, and provide basic data for attitude parameter measurement;

[0028] Acceleration Data Unit: This unit is used to collect linear acceleration signal data of the ship during navigation, and to help correct the cumulative error that occurs during the gyroscope measurement process;

[0029] Temperature drift compensation and zero bias correction unit: The unit monitors the operating temperature of the MEMS gyroscope and accelerometer in real time, and performs temperature drift compensation on the measurement data by combining the preset temperature-drift characteristic curve. It calculates the zero bias error and performs dynamic correction by periodically collecting the static output value of the sensor.

[0030] Data fusion processing unit: The unit performs fusion processing on the compensated and corrected attitude data using the Kalman filter algorithm, and predicts the trend of ship attitude change in a short period of time based on historical driving data.

[0031] Preferably, the environmental monitoring module specifically includes:

[0032] Ambient temperature unit: The unit detects temperature data in the ship's navigation environment in real time, converts the temperature signal into a transmittable electrical signal, and sends it to the data processing module;

[0033] Ambient humidity unit: The unit is used to collect humidity data of the environment around the ship, obtain humidity changes and output measurement signals;

[0034] Forward scattering visibility meter unit: The unit calculates the visibility value by detecting the forward scattering characteristics of light in the atmosphere and transmits the data to the data processing module to correct laser propagation errors;

[0035] Raindrop detection unit: The unit is used to identify rainfall during ship navigation. It detects raindrop size and rainfall intensity through capacitive detection principle and feeds the data back to the data processing module.

[0036] Preferably, the data processing module specifically includes:

[0037] Data receiving unit: This unit is used for various types of data from each module, and performs preliminary verification on the received data. After verifying the integrity of the data, it is transmitted to the subsequent processing unit.

[0038] Attitude compensation and correction unit: The unit performs tilt correction on the laser propagation distance transmitted from the laser receiving module based on the roll angle and pitch angle data obtained by the attitude perception module, and calculates the distance deviation in the vertical direction;

[0039] Laser propagation speed correction unit: The unit analyzes the impact of different environmental conditions on the propagation speed of laser in air based on the data collected by the environmental monitoring module, and dynamically corrects the laser propagation speed;

[0040] Clearance height calculation unit: The unit integrates the vertical distance deviation after attitude compensation correction, the corrected laser propagation speed, and the installation height of the laser emitting module and the ship deck, and calculates and obtains the real-time clearance height data of the ship through the clearance height calculation formula;

[0041] Scheduling and Management Unit: This unit is used to schedule the workflow of each unit in real time, including data reception, attitude compensation and correction, speed correction, and altitude calculation.

[0042] Preferably, the data storage module specifically includes:

[0043] Data classification and receiving unit: The unit is used to receive the ship's clearance height calculation data, raw data collected by each module and system operation log transmitted by the data processing module, and classify and label them based on data type;

[0044] Dual-media storage unit: The unit adopts a collaborative working mode of SD card and solid-state drive. The SD card prioritizes the storage of critical real-time data, while the solid-state drive is used for long-term storage of large amounts of historical data.

[0045] Data encryption unit: The unit generates an AES-256 encryption key based on the ship's MMSI number dynamic key generator, performs real-time encryption processing on all data stored in the SD card and solid-state drive, and performs blockchain-style encryption on the data written to the solid-state drive. Each data block contains the hash check value of the previous block.

[0046] Preferably, the display warning module specifically includes:

[0047] Tiered early warning unit: The unit compares the clearance height data with the threshold of each level by preset multiple clearance height safety thresholds, and triggers the corresponding level of early warning strategy;

[0048] Audible and visual warning unit: The unit compares the clearance height data with the preset safety threshold in real time. When the clearance height is detected to be lower than the threshold, it immediately triggers an audible and visual alarm, which emits a warning sound through a buzzer and a visual warning through an LED light.

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

[0050] Through a multi-module collaborative working mode, the laser emission module can flexibly adjust parameters according to the ship's speed and measurement accuracy, and paired with a high-performance laser receiver module, ensures accurate laser signal capture. Dual-mode positioning combined with differential correction ensures continuous and accurate positioning, while MEMS gyroscopes and accelerometers, along with Kalman filtering algorithms, enable precise perception and prediction of the ship's attitude. The environmental monitoring module collects data from multiple dimensions to help correct laser propagation errors. The data processing module integrates multi-source data, accurately calculates the clearance height through attitude compensation and speed correction, and the data storage module provides dual-media storage with robust encryption protection. Simultaneously, tiered audible and visual warnings can promptly alert to risks, effectively preventing collisions caused by insufficient clearance height and improving navigation safety and reliability. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the system proposed in this invention;

[0052] Figure 2 This is a diagram of the laser emission module proposed in this invention;

[0053] Figure 3This is a diagram of the laser receiving module proposed in this invention;

[0054] Figure 4 This is a diagram of the positioning module proposed in this invention;

[0055] Figure 5 This is a diagram of the attitude sensing module proposed in this invention;

[0056] Figure 6 This is a diagram of the environmental monitoring module proposed in this invention;

[0057] Figure 7 This is a diagram of the data processing module proposed in this invention;

[0058] Figure 8 This is a diagram of the data storage module proposed in this invention;

[0059] Figure 9 This is a diagram of the display warning module proposed in this invention. Detailed Implementation

[0060] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0061] See Figure 1 As shown, a laser measurement system for the clearance height of a navigating vessel includes:

[0062] Laser emission module: The module is used to emit multiple laser beams into the measurement area above the ship, and adjust the laser emission frequency and the distribution density of the laser beams according to the ship's speed and measurement accuracy requirements;

[0063] Laser receiving module: This module is set up in correspondence with the laser emitting module and is used to receive the laser reflection signal after being reflected by obstacles in the measurement area, and convert the received optical signal into an electrical signal;

[0064] Positioning module: The module obtains the ship's real-time geographical location information and navigation trajectory through a dual-mode positioning method using both the BeiDou Navigation Satellite System and the GPS Navigation System;

[0065] Attitude perception module: The module is used to collect the attitude parameters of the ship during navigation, capture the dynamic attitude changes of the ship in real time through MEMS gyroscope and accelerometer, and perform temperature drift compensation and zero bias correction on the measurement data.

[0066] Environmental monitoring module: The module is used to detect relevant parameters of the ship's navigation environment, including ambient temperature, humidity, visibility, and wind speed and direction;

[0067] Data processing module: This module is electrically connected to the laser receiving module, positioning module, attitude sensing module, and environmental monitoring module. It is used to receive data transmitted by each module, perform attitude compensation and correction on the laser measurement data, and calculate the ship's clearance height by combining the positioning data and environmental parameters.

[0068] Data storage module: The module is electrically connected to the data processing module and is used to store the ship's clearance height data calculated and obtained by the data processing module, the raw data collected by each module, and the system operation log, and is encrypted using an encryption algorithm;

[0069] Display and warning module: The module is electrically connected to the data processing module and is used to display ship data in real time. When the calculated ship clearance height is lower than the preset safety threshold, a warning signal is issued through an audible and visual alarm.

[0070] See Figure 2 As shown, the laser emitting module specifically includes:

[0071] Laser generator: The laser generator serves as the source of laser emission, generating an initial laser beam with a wavelength between 532nm and 1064nm, providing a basic light source for laser measurement;

[0072] Beam shaper: The beam shaper processes the initial laser beam generated by the laser generator and shapes it into a laser beam with high parallelism and uniform spot size, thereby reducing the impact of beam divergence on measurement accuracy;

[0073] Scanning drive device: The device is used to drive the shaped laser beam to move within the measurement area. By using one-dimensional or two-dimensional scanning, the scanning speed is adjusted according to the ship's sailing speed and measurement accuracy requirements to achieve full coverage detection of the measurement area.

[0074] Specifically, based on the ship's real-time sailing speed and measurement accuracy requirements, the scanning mode, scanning speed, and scanning range of the scanning drive device are set; at the same time, the position calibration unit inside the device is activated to calibrate the initial position of the scanning motor to zero, ensuring that the scanning starting point is consistent with the set position;

[0075] The shaped laser beam is guided into the galvanometer and rotating mirror of the scanning drive device. According to the set scanning parameters, the drive signal is sent to the scanning motor to drive the reflection unit to move in a regular manner. During one-dimensional scanning, the reflection unit rotates or swings along a single axis, and during two-dimensional scanning, it moves alternately or synchronously along two axes, thereby driving the laser beam to move along a preset trajectory within the measurement area.

[0076] The device monitors the movement position and speed of the reflective unit in real time using a built-in position sensor to ensure that the deviation between the scanning trajectory and the set trajectory is ≤0.1mm. At the same time, it dynamically adjusts the scanning speed based on the real-time speed changes fed back by the ship's navigation system to avoid scanning discontinuities in the measurement area caused by ship movement. If the reflective unit is detected to be stuck or its speed is abnormal, the scanning is immediately paused and the calibration program is restarted. The scanning continues after the fault is eliminated.

[0077] After the scanning drive device completes a scan of the preset range, the control system compares the overlap between the actual scanning trajectory and the set area to confirm whether there are any unscanned blind spots. If there are blind spots, the scanning start point and trajectory parameters are adjusted according to the location of the blind spots, and the supplementary scanning program is started until the laser beam completely covers the entire measurement area, forming complete area detection data, which provides a comprehensive beam coverage basis for subsequent laser measurement and analysis.

[0078] See Figure 3 As shown, the laser receiving module specifically includes:

[0079] Photoelectric detection unit: The unit uses an avalanche photodiode to receive weak laser reflection signals reflected by obstacles and convert them into initial electrical signals;

[0080] Signal conditioning circuit unit: The unit amplifies the weak electrical signal output by the photoelectric detection unit and filters out environmental noise through a second-order active low-pass filter circuit to improve signal quality;

[0081] A / D Conversion Unit: The unit uses a 16-bit high-speed A / D converter to accurately convert the conditioned analog electrical signal into a digital signal.

[0082] Specifically, the amplified electrical signal enters a second-order active low-pass filter circuit. The cutoff frequency of the filter circuit is set according to the ambient noise frequency of the measurement scene. The filter circuit filters out high-frequency ambient noise and low-frequency interference signals through the synergistic effect of capacitors, resistors and operational amplifiers, making the output signal waveform smoother.

[0083] The A / D converter periodically samples the input analog signal according to the set sampling rate, compares the analog voltage value at each sampling moment with the 16-bit quantization range, a total of 65,536 quantization levels, to determine the corresponding digital quantity; during the conversion process, the converter's built-in calibration circuit corrects the quantization error in real time to ensure that the conversion accuracy error is ≤ ±1LSB.

[0084] See Figure 4 As shown, the positioning module specifically includes:

[0085] Dual-mode positioning unit: The unit receives satellite signals from the Beidou navigation system and the GPS navigation system to obtain the ship's real-time geographical location information and navigation trajectory. When the signal of one navigation system is weaker than a preset threshold, it automatically switches to the other system to obtain continuous positioning data.

[0086] Differential positioning module: The unit receives differential correction information sent by the differential base station and corrects the original positioning data obtained by the dual-mode positioning unit in real time.

[0087] Specifically, the module obtains real-time raw positioning data from the dual-mode positioning unit and matches the timestamp of the raw positioning data with the timestamp of the differential correction information. If the time match is successful, the module corrects each error in the raw positioning data one by one according to the error compensation parameters in the correction information. For example, if the original latitude coordinate is 30°15′20.5″, it is adjusted to 30°15′20.3″ after correction to improve coordinate accuracy. If the time does not match, the correction information is discarded and the correction parameters of the previous successful match are used for temporary correction until new correction information with time match is obtained.

[0088] The module transmits the corrected positioning data to the dual-mode positioning unit, updates the unit's positioning data and navigation trajectory, and simultaneously outputs it to the ship's navigation system to provide high-precision positioning support for navigation control. The module has a built-in accuracy detection unit that periodically compares the positioning data deviation before and after correction. If the deviation exceeds 0.2m, the differential correction information is re-analyzed and the matching process is checked to eliminate problems such as information transmission errors and time synchronization deviations, ensuring that the corrected positioning data meets the ship's high-precision navigation requirements.

[0089] See Figure 5 As shown, the attitude perception module specifically includes:

[0090] MEMS gyroscope unit: The unit is used to collect angular motion information during ship navigation, capture the dynamic changes in roll angle, pitch angle and heading angle, and provide basic data for attitude parameter measurement;

[0091] Acceleration Data Unit: This unit is used to collect linear acceleration signal data of the ship during navigation, and to help correct the cumulative error that occurs during the gyroscope measurement process;

[0092] Temperature drift compensation and zero bias correction unit: The unit monitors the operating temperature of the MEMS gyroscope and accelerometer in real time, and performs temperature drift compensation on the measurement data by combining the preset temperature-drift characteristic curve. It calculates the zero bias error and performs dynamic correction by periodically collecting the static output value of the sensor.

[0093] Data fusion processing unit: The unit performs fusion processing on the compensated and corrected attitude data using the Kalman filter algorithm, and predicts the trend of ship attitude change in a short period of time based on historical driving data.

[0094] Specifically, the operating temperature of the MEMS gyroscope and accelerometer is monitored in real time by a temperature sensor, and temperature data is recorded at a frequency of 10Hz to form a temperature change curve. At the same time, the preset temperature-drift characteristic curve inside the module is read (the curve is based on the sensor's factory calibration data and records the drift error value at different temperatures, such as the gyroscope zero bias drift of +0.1° / h for every 10° increase in temperature).

[0095] By comparing the real-time monitored temperature data with the preset temperature-drift characteristic curve, the drift error values ​​of the gyroscope and accelerometer at the current temperature are calculated. Based on the calculated drift error values, the angular motion data collected by the gyroscope and the linear acceleration data collected by the accelerometer are compensated in reverse to eliminate the influence of temperature changes on the measurement data.

[0096] The zero-bias correction program is triggered according to the set cycle. At this time, the module controls the sensor to enter the static acquisition mode. If the ship cannot be completely stationary, the static output value of the sensor is acquired based on the ship's uniform straight-line navigation state. The static output value is compared with the preset zero-bias reference value to calculate the zero-bias error. The zero-bias error value is fed back to the data acquisition unit in real time to dynamically correct the subsequent acquired measurement data.

[0097] The Kalman filter algorithm is used to process preprocessed angular motion data and linear acceleration data as input. Through the prediction-update iteration process of the algorithm, the advantages of the two types of data are combined. Gyroscope data has good high-frequency response but is prone to error accumulation, while acceleration data has no error accumulation but is greatly affected by high-frequency noise. Random noise in the data is filtered out to generate smooth and accurate ship attitude parameters, and the fused attitude data is transmitted to the ship navigation system.

[0098] The unit calls upon the ship's historical navigation data stored internally and combines it with the current fused attitude data to analyze the ship's attitude change patterns. Based on these patterns, it predicts the ship's attitude change trend within the next 5-10 seconds and outputs the prediction results to the bridge display terminal simultaneously, providing the crew with a reference for adjusting navigation operations in advance, such as adjusting the rudder angle or reducing the speed.

[0099] See Figure 6 As shown, the environmental monitoring module specifically includes:

[0100] Ambient temperature unit: The unit detects temperature data in the ship's navigation environment in real time, converts the temperature signal into a transmittable electrical signal, and sends it to the data processing module;

[0101] Ambient humidity unit: The unit is used to collect humidity data of the environment around the ship, obtain humidity changes and output measurement signals;

[0102] Forward scattering visibility meter unit: The unit calculates the visibility value by detecting the forward scattering characteristics of light in the atmosphere and transmits the data to the data processing module to correct laser propagation errors;

[0103] Raindrop detection unit: The unit is used to identify rainfall during ship navigation. It detects raindrop size and rainfall intensity through capacitive detection principle and feeds the data back to the data processing module.

[0104] Specifically, the infrared light source emits a stable beam of light at a set frequency. When the beam of light propagates in the atmosphere, it is scattered by particles in the air. The receiving optical system captures the forward scattered light at an angle of 30°-50° to the direction of beam propagation and converts the scattered light signal into an electrical signal. The signal detection module measures the intensity of the electrical signal and, combined with the scattering coefficient preset inside the instrument and the visibility conversion relationship based on atmospheric optics principles, calculates the visibility value of the current environment.

[0105] The calculated visibility data is transmitted to the data processing module in real time. The data processing module corrects the laser propagation error of the laser emission module based on the visibility value. If the visibility meter detects that the visibility is lower than the safety threshold, it immediately sends a low visibility warning to the cockpit and suggests slowing down the navigation. At the same time, it encrypts the data acquisition frequency to provide high-frequency data support for laser measurement error correction.

[0106] A capacitive raindrop sensor creates a capacitive field through surface electrodes. When a raindrop falls on the sensor surface, it changes the dielectric constant between the electrodes, causing a change in capacitance. The sensor converts this capacitance change into an electrical signal, which is then transmitted to a signal analysis module. The module analyzes the amplitude and frequency of the electrical signal to identify the current raindrop size and rainfall intensity. It also records information such as the start time and duration of rainfall to form rainfall process data.

[0107] See Figure 7 As shown, the data processing module specifically includes:

[0108] Data receiving unit: This unit is used for various types of data from each module, and performs preliminary verification on the received data. After verifying the integrity of the data, it is transmitted to the subsequent processing unit.

[0109] Attitude compensation and correction unit: The unit performs tilt correction on the laser propagation distance transmitted from the laser receiving module based on the roll angle and pitch angle data obtained by the attitude perception module, and calculates the distance deviation in the vertical direction;

[0110] Laser propagation speed correction unit: The unit analyzes the impact of different environmental conditions on the propagation speed of laser in air based on the data collected by the environmental monitoring module, and dynamically corrects the laser propagation speed;

[0111] Clearance height calculation unit: The unit integrates the vertical distance deviation after attitude compensation correction, the corrected laser propagation speed, and the installation height of the laser emitting module and the ship deck, and calculates and obtains the real-time clearance height data of the ship through the clearance height calculation formula;

[0112] Scheduling and Management Unit: This unit is used to schedule the workflow of each unit in real time, including data reception, attitude compensation and correction, speed correction, and altitude calculation.

[0113] Specifically, the formula for correcting the laser propagation speed is:

[0114]

[0115] Among them, v 修正 The corrected laser propagation speed is given by v0, where v0 is the vacuum propagation speed of the laser under standard atmospheric pressure, T0 is the standard ambient temperature, P0 is the standard atmospheric pressure, T is the actual ambient temperature collected by the environmental monitoring module, P is the actual atmospheric pressure collected by the environmental monitoring module, and f is the actual ambient relative humidity collected by the environmental monitoring module.

[0116] Based on roll and pitch angle data, the tilt angle between the laser propagation direction and the vertical direction is analyzed. For example, the roll angle causes the laser to tilt in the left and right direction, and the pitch angle causes the laser to tilt in the front and back direction. The distance deviation in the vertical direction is calculated. The original laser propagation distance is corrected according to the deviation value to obtain the actual distance in the vertical direction.

[0117] The corrected vertical distance data is compared with historical correction data to verify the correction accuracy. If the deviation exceeds the threshold, the integrity of the attitude data and the validity of the laser distance data are checked. After troubleshooting, the deviation is recalculated and corrected.

[0118] Based on the preset environmental factor-velocity correction model, the comprehensive velocity correction coefficient is calculated in combination with the current environmental data; the reference value of the laser propagation velocity in a standard atmospheric environment is obtained, and the reference value is multiplied by the comprehensive correction coefficient to obtain the actual laser propagation velocity in the current environment; if rainfall is detected, an additional rainfall correction coefficient is added to further optimize the velocity accuracy; the corrected velocity data is transmitted to the clearance height calculation unit in real time, and the environmental data and the corresponding correction coefficient are stored at the same time to form a correction log;

[0119] The real-time clearance height of a vessel is calculated by integrating all basic data using the clearance height calculation formula. During the calculation process, the validity of the data is monitored in real time. If any basic data is missing, the calculation is immediately paused and awaits data retransmission to avoid invalid results. The clearance height calculation formula is as follows:

[0120] H=(L corr ×cosθ)+H install -Δh env

[0121] Where H is the real-time clearance height of the ship, and L corr The actual laser propagation distance is the laser propagation speed corrected, θ is the ship's tilt angle, cosθ is the attitude compensation coefficient, and H... install Δh is the fixed installation height of the laser emission module on the ship's deck. env This refers to the correction amount for headroom caused by environmental factors.

[0122] See Figure 8 As shown, the data storage module specifically includes:

[0123] Data classification and receiving unit: The unit is used to receive the ship's clearance height calculation data, raw data collected by each module and system operation log transmitted by the data processing module, and classify and label them based on data type;

[0124] Dual-media storage unit: The unit adopts a collaborative working mode of SD card and solid-state drive. The SD card prioritizes the storage of critical real-time data, while the solid-state drive is used for long-term storage of large amounts of historical data.

[0125] Data encryption unit: The unit generates an AES-256 encryption key based on the ship's MMSI number dynamic key generator, performs real-time encryption processing on all data stored in the SD card and solid-state drive, and performs blockchain-style encryption on the data written to the solid-state drive. Each data block contains the hash check value of the previous block.

[0126] Specifically, the received data is automatically classified based on its format and source. The data for calculating the clearance height is labeled with "clearance height - timestamp - positioning coordinates"; the raw data of each module is labeled with "module name - data category - timestamp"; and the system operation log is labeled with "log type - timestamp - module number". After labeling, a unique identification code is assigned to each group of data.

[0127] The ship's MMSI number is read as the basis for key generation. The built-in dynamic key generator, combined with the current timestamp and device hardware number, generates an AES-256 encryption key. If the ship's MMSI number changes, the new MMSI number is re-entered with administrator authorization, and the key generator is re-initialized.

[0128] Before data is written to the SD card and solid-state drive, the encryption unit performs real-time AES-256 encryption on the data. For historical data written to the solid-state drive, encryption is completed synchronously during the migration process to ensure that all data in the storage medium is in an encrypted state. If a data transmission interruption is detected during the encryption process, encryption is immediately terminated and unfinished encrypted files are deleted to avoid generating invalid data.

[0129] For encrypted data written to solid-state drives, a blockchain-style encryption mechanism is further adopted: each batch of data is packaged into a data block, and each block contains a block header and a block body; when a new block is generated, the hash check value of the previous block is first calculated and written into the current block header, and then the hash value of the current block as a whole is calculated to form a chain-like associated structure.

[0130] See Figure 9 As shown, the warning module specifically includes:

[0131] Tiered early warning unit: The unit compares the clearance height data with the threshold of each level by preset multiple clearance height safety thresholds, and triggers the corresponding level of early warning strategy;

[0132] Audible and visual warning unit: The unit compares the clearance height data with the preset safety threshold in real time. When the clearance height is detected to be lower than the threshold, it immediately triggers an audible and visual alarm, which emits a warning sound through a buzzer and a visual warning through an LED light.

[0133] Specifically, multiple safety thresholds for clearance height are set based on ship type and navigation scenario. For example, three thresholds are set for inland waterway cargo ships: safety threshold ≥ 12 meters, warning threshold 8-12 meters, and danger threshold < 8 meters. In cross-sea bridge waters, the danger threshold can be raised to < 15 meters. Combined with the actual draft and deck load of the ship, if the hull sinks when fully loaded, the safety threshold needs to be lowered by 2-3 meters. The thresholds are dynamically calibrated to ensure that the thresholds match the real-time navigation status of the ship.

[0134] Based on the threshold comparison results, different levels of early warning strategies are triggered:

[0135] Safety level: The unit outputs a safety status signal, which is displayed as a green status indicator on the cab display terminal. It does not trigger any additional warning operations, but only records the average clearance height for each hour to the warning log.

[0136] Alert Level: Triggering the alert warning strategy sends a yellow warning to the bridge display terminal and pushes the warning information to the crew's mobile terminal; increases the frequency of airspace height data collection, enhances the visibility of the environmental monitoring module and rainfall data feedback, and provides the crew with more decision-making references;

[0137] Hazard Level: Triggering the hazard warning strategy immediately sends a forced deceleration command to the ship's navigation system, and a red flashing warning window pops up on the bridge display terminal, indicating a dangerous clearance height. The crew is instructed to immediately adjust the course or reduce speed. At the same time, the data backtracking function is activated to retrieve the clearance height change curve of the past 5 minutes, analyze the height descent trend, and provide data support for the crew to formulate avoidance measures.

[0138] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0139] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0140] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser measurement system for the clearance height of a navigating vessel, characterized in that, include: Laser emission module: The module is used to emit multiple laser beams into the measurement area above the ship, and adjust the laser emission frequency and the distribution density of the laser beams according to the ship's speed and measurement accuracy requirements; Laser receiving module: This module is set up in correspondence with the laser emitting module and is used to receive the laser reflection signal after being reflected by obstacles in the measurement area, and convert the received optical signal into an electrical signal; Positioning module: The module obtains the ship's real-time geographical location information and navigation trajectory through a dual-mode positioning method using both the BeiDou Navigation Satellite System and the GPS Navigation System; Attitude perception module: The module is used to collect the attitude parameters of the ship during navigation, capture the dynamic attitude changes of the ship in real time through MEMS gyroscope and accelerometer, and perform temperature drift compensation and zero bias correction on the measurement data. Environmental monitoring module: The module is used to detect relevant parameters of the ship's navigation environment, including ambient temperature, humidity, visibility, and wind speed and direction; Data processing module: This module is electrically connected to the laser receiving module, positioning module, attitude sensing module, and environmental monitoring module. It is used to receive data transmitted by each module, perform attitude compensation and correction on the laser measurement data, and calculate the ship's clearance height by combining the positioning data and environmental parameters. Data storage module: The module is electrically connected to the data processing module and is used to store the ship's clearance height data calculated and obtained by the data processing module, the raw data collected by each module, and the system operation log, and is encrypted using an encryption algorithm; Display and warning module: The module is electrically connected to the data processing module and is used to display ship data in real time. When the calculated ship clearance height is lower than the preset safety threshold, a warning signal is issued through an audible and visual alarm.

2. The laser measurement system for the clearance height of a navigating vessel according to claim 1, characterized in that, The laser emitting module specifically includes: Laser generator: The laser generator serves as the source of laser emission, generating an initial laser beam with a wavelength between 532nm and 1064nm, providing a basic light source for laser measurement; Beam shaper: The beam shaper processes the initial laser beam generated by the laser generator and shapes it into a laser beam with high parallelism and uniform spot size, thereby reducing the impact of beam divergence on measurement accuracy; Scanning drive device: The device is used to drive the shaped laser beam to move within the measurement area. By using one-dimensional or two-dimensional scanning, the scanning speed is adjusted according to the ship's sailing speed and measurement accuracy requirements to achieve full coverage detection of the measurement area.

3. The laser measurement system for the clearance height of a navigating vessel according to claim 1, characterized in that, The laser receiving module specifically includes: Photoelectric detection unit: The unit uses an avalanche photodiode to receive weak laser reflection signals reflected by obstacles and convert them into initial electrical signals; Signal conditioning circuit unit: The unit amplifies the weak electrical signal output by the photoelectric detection unit and filters out environmental noise through a second-order active low-pass filter circuit to improve signal quality; A / D Conversion Unit: The unit uses a 16-bit high-speed A / D converter to accurately convert the conditioned analog electrical signal into a digital signal.

4. The laser measurement system for the clearance height of a navigating vessel according to claim 1, characterized in that, The positioning module specifically includes: Dual-mode positioning unit: The unit receives satellite signals from the Beidou navigation system and the GPS navigation system to obtain the ship's real-time geographical location information and navigation trajectory. When the signal of one navigation system is weaker than a preset threshold, it automatically switches to the other system to obtain continuous positioning data. Differential positioning module: The unit receives differential correction information sent by the differential base station and corrects the original positioning data obtained by the dual-mode positioning unit in real time.

5. The laser measurement system for the clearance height of a navigating vessel according to claim 1, characterized in that, The attitude perception module specifically includes: MEMS gyroscope unit: The unit is used to collect angular motion information during ship navigation, capture the dynamic changes in roll angle, pitch angle and heading angle, and provide basic data for attitude parameter measurement; Acceleration Data Unit: This unit is used to collect linear acceleration signal data of the ship during navigation, and to help correct the cumulative error that occurs during the gyroscope measurement process; Temperature drift compensation and zero bias correction unit: The unit monitors the operating temperature of the MEMS gyroscope and accelerometer in real time, and performs temperature drift compensation on the measurement data by combining the preset temperature-drift characteristic curve. It calculates the zero bias error and performs dynamic correction by periodically collecting the static output value of the sensor. Data fusion processing unit: The unit performs fusion processing on the compensated and corrected attitude data using the Kalman filter algorithm, and predicts the trend of ship attitude change in a short period of time based on historical driving data.

6. The laser measurement system for the clearance height of a navigating vessel according to claim 1, characterized in that, The environmental monitoring module specifically includes: Ambient temperature unit: The unit detects temperature data in the ship's navigation environment in real time, converts the temperature signal into a transmittable electrical signal, and sends it to the data processing module; Ambient humidity unit: The unit is used to collect humidity data of the environment around the ship, obtain humidity changes and output measurement signals; Forward scattering visibility meter unit: The unit calculates the visibility value by detecting the forward scattering characteristics of light in the atmosphere and transmits the data to the data processing module to correct laser propagation errors; Raindrop detection unit: The unit is used to identify rainfall during ship navigation. It detects raindrop size and rainfall intensity through capacitive detection principle and feeds the data back to the data processing module.

7. The laser measurement system for the clearance height of a navigating vessel according to claim 1, characterized in that, The data processing module specifically includes: Data receiving unit: This unit is used for various types of data from each module, and performs preliminary verification on the received data. After verifying the integrity of the data, it is transmitted to the subsequent processing unit. Attitude compensation and correction unit: The unit performs tilt correction on the laser propagation distance transmitted from the laser receiving module based on the roll angle and pitch angle data obtained by the attitude perception module, and calculates the distance deviation in the vertical direction; Laser propagation speed correction unit: The unit analyzes the impact of different environmental conditions on the propagation speed of laser in air based on the data collected by the environmental monitoring module, and dynamically corrects the laser propagation speed; Clearance height calculation unit: The unit integrates the vertical distance deviation after attitude compensation correction, the corrected laser propagation speed, and the installation height of the laser emitting module and the ship deck, and calculates and obtains the real-time clearance height data of the ship through the clearance height calculation formula; Scheduling and Management Unit: This unit is used to schedule the workflow of each unit in real time, including data reception, attitude compensation and correction, speed correction, and altitude calculation.

8. The laser measurement system for the clearance height of a navigating vessel according to claim 1, characterized in that, The data storage module specifically includes: Data classification and receiving unit: The unit is used to receive the ship's clearance height calculation data, raw data collected by each module and system operation log transmitted by the data processing module, and classify and label them based on data type; Dual-media storage unit: The unit adopts a collaborative working mode of SD card and solid-state drive. The SD card prioritizes the storage of critical real-time data, while the solid-state drive is used for long-term storage of large amounts of historical data. Data encryption unit: The unit generates an AES-256 encryption key based on the ship's MMSI number dynamic key generator, performs real-time encryption processing on all data stored in the SD card and solid-state drive, and performs blockchain-style encryption on the data written to the solid-state drive. Each data block contains the hash check value of the previous block.

9. A laser measurement system for the clearance height of a navigating vessel according to claim 1, characterized in that, The display and warning module specifically includes: Tiered early warning unit: The unit compares the clearance height data with the threshold of each level by preset multiple clearance height safety thresholds, and triggers the corresponding level of early warning strategy; Audible and visual warning unit: The unit compares the clearance height data with the preset safety threshold in real time. When the clearance height is detected to be lower than the threshold, it immediately triggers an audible and visual alarm, which emits a warning sound through a buzzer and a visual warning through an LED light.

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