Real-time dynamic calibration method for single-beam echo sounders

Abstract

The application relates to a kind of detection equipment verification method.The purpose is to provide a real-time dynamic verification method of single-beam depth finder, which should have the characteristics of high verification accuracy, simple operation and strong practicability.The technical scheme is: a real-time dynamic verification method of single-beam depth finder, comprising: (1) laying a straight line travelling crane guide along the pool bank, and the single-arm travelling crane is movably positioned on the guide; (2) a standard flat plate is arranged at one end of the pool, the standard flat plate vertically extends into the water, and the plane of the flat plate is perpendicular to the straight line travelling crane guide; (3) the sound velocity in the water is measured by using a sound velocity meter, and the single-beam depth finder is input; (4) the single-arm travelling crane is provided with a single-beam depth finder transducer, the transducer is submerged to a certain depth, and the transducer emits sound waves parallel to the straight line travelling crane guide towards the standard flat plate.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of detection equipment verification method, especially real-time dynamic verification method of single-beam depth finder. BACKGROUND

[0002] The principle of single-beam depth finder is to use a set of transmitting transducers to emit sound waves underwater, so that the sound waves propagate along the water medium until they are reflected back after hitting the target. The reflected sound waves are received by the receiving transducer, and by measuring the time difference between the transmission and reception of sound waves and the speed of sound in water, the distance between the transducer and the target is obtained. Currently, single-beam depth finder is widely used in all water-related fields that require water depth information, such as ocean surveying, port channel, ocean engineering, and ocean surveying, due to its low cost and easy operation. Therefore, it is particularly important to verify the accuracy of single-beam depth finder.

[0003] CN114166158A discloses a depth finder measurement and detection calibration system, which carries single-beam depth finder and laser range finder on a measuring vehicle, and sets a laser reflection target in front. The distance between the single-beam depth finder and the laser reflection target is obtained simultaneously and compared, and the measuring vehicle is moved to change the distance between the measuring vehicle and the laser reflection target, thereby verifying the single-beam depth finder at different distances. However, this system uses indoor pool static verification method, which does not match the dynamic use condition of single-beam depth finder (actual data collection is done in water by walk-around method), thus there is error; and each time the distance between the single-beam depth finder and the laser reflection target is obtained, the measuring vehicle is in a stopped state (the measuring vehicle is moved every other time, and each time the measuring vehicle is moved, the measuring vehicle is stopped, and the range value is read manually), and the range value of the laser range finder is used as the "true value", which increases the error source. It cannot truly and objectively reflect the precision and accuracy of single-beam depth finder. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the background art and provide a real-time dynamic verification method for single-beam depth finder, which should have the characteristics of high verification accuracy, simple operation and strong practicality.

[0005] The technical solution provided by the present application is:

[0006] The real-time dynamic verification method for single-beam depth finder comprises:

[0007] (1) A straight line travel guide rail is laid along the pool shore, and a single-arm travel crane is movably positioned on the guide rail;

[0008] (2) A standard flat plate is set at one end of the pool, which vertically extends into the water and the plane of the flat plate is perpendicular to the straight line travel guide rail;

[0009] (3) using the sound velocity meter to measure the sound velocity in water, inputting the single-beam depth finder;

[0010] (4) the single-beam depth finder transducer is arranged on the single-arm travelling crane, the transducer is immersed in water at a certain depth, and the transducer emits sound waves parallel to the linear travelling crane guide rail to the standard plate;

[0011] (5) the parameters of the single-arm travelling crane are set, the initial positions of the single-arm travelling crane are kept consistent, the single-arm travelling crane is repeatedly operated 10 times at the same speed, the depth curves measured by the single-beam depth finder and the operation positions of the single-arm travelling crane are recorded each time, the operation positions of the single-arm travelling crane are converted into the horizontal distances from the single-arm travelling crane to the standard plate, and the distance curves of the single-arm travelling crane are obtained;

[0012] (6) taking the depth curve of the single-beam depth finder in the first time as a reference, the depths measured by the single-beam depth finder are extracted at intervals of 0.5 s, and the indication errors of each node of the depth curves in the second, third, fourth, fifth, sixth, seventh, eighth, ninth and tenth times are calculated respectively;

[0013] (7) the average values and standard deviations of the indication errors of each time node in each operation are calculated, and the measurement stability evaluation of the single-beam depth finder is realized;

[0014] The average values and standard deviations of the indication errors of each time node in each operation are calculated according to the following formula respectively:

[0015]

[0016]

[0017] In the formula, is the indication error of the time node corresponding to the depth value of the single-beam depth finder in the first time in the second, third, fourth, fifth, sixth, seventh, eighth, ninth and tenth operation, i = 1, 2, 3…n, n is the number of time nodes, is the average value of the indication errors of each node in the second, third, fourth, fifth, sixth, seventh, eighth, ninth and tenth operation, i = 2-10. is the standard deviation of the indication errors of the time node corresponding to the depth value of the single-beam depth finder in the first time in the second, third, fourth, fifth, sixth, seventh, eighth, ninth and tenth operation.

[0018] (8) taking the distance curve of the single-arm travelling crane as a reference (true value), the depths measured by the single-beam depth finder are extracted at intervals of 0.5 s, and the indication errors of each time node of the depth curves measured in the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth and tenth time and the distance curve of the single-arm travelling crane in the same time are calculated;

[0019] (9) the average values and standard deviations of the indication errors of each time node are calculated, and the accuracy evaluation of the single-beam depth finder is realized;

[0020] The average value and standard deviation of the indication errors at each time point of the depth curves and the single-arm travel distance curves of the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 10th depth curves are calculated using the following formulas:

[0021]

[0022]

[0023] In the formula: The error values ​​for each time point on the single-arm traveling distance curve for the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 10th runs are shown. =1, 2, 3...m, where m is the number of time points. The mean value of the node indication error for the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 10th runs, i = 1 to 10. The standard deviation of the indication error of each node of the single-beam echo sounder depth curve and single-arm travel distance curve for the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 10th times.

[0024] The method for measuring the speed of sound in water using a sound velocity meter in step (3) is as follows: the sound velocity meter runs along the guide rail of the trolley and measures the speed of sound at a depth of 1m underwater every 1m, and the average speed of sound is then input into the single-beam depth sounder.

[0025] The certain depth mentioned in step (4) is 1 meter.

[0026] The beneficial effects of this invention are: the calibration device and method provided by this invention have high calibration accuracy and are easy to operate; technicians do not need to have hardware knowledge of single-beam echo sounders to complete the calibration; through practical operation, this invention has good practical applicability. Furthermore, the real-time dynamic calibration process of this invention is more consistent with the actual use environment of single-beam echo sounders, and the calibration results are more convincing. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the usage state of an embodiment of the present invention.

[0028] The diagram is labeled as follows: 1. Single-arm crane; 2. Single-beam depth sounder transducer; 3. Transducer acoustic wave axis; 4. Sound velocity profiler; 5. Starting point position; 6. GNSS equipment; 7. Standard surface. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0030] Single-beam depth sounder principle:

[0031] A) The working principle of the depth finder is to use the phenomenon that sound waves penetrate the medium and are reflected at the surface of different media, use the sound wave transducer (probe) to emit sound waves, and measure and calculate the water depth by measuring the time difference between the emitted waves and the return waves.

[0032] B) Assuming that the propagation speed of sound waves in water is V, the ultrasonic waves emitted by the transducer (probe) reach the water bottom and are reflected back to the probe to be received, and the time experienced by the signal during the round trip is t, then:

[0033] .

[0034] The basic idea of the present application is:

[0035] The GNSS is mainly used to provide a high-precision time reference, and the time reference is synchronized to the single-beam depth finder and the single-arm travelling crane, so as to realize the time synchronization of the hardware devices of the two; the sound velocity meter is used to measure the sound velocity in water, and a sound velocity field is constructed; then the single-arm travelling crane control system is used to control the travelling crane to make reciprocating motion along the long side wall of the pool, the position of the single-arm travelling crane is recorded in real time, the position of the travelling crane is converted into the distance from the travelling crane to the standard surface on one side of the pool, the measured depth of the single-beam depth finder is recorded (after sound velocity correction), and then the measurement distance or depth curve of the two under the same time reference is obtained, the difference under the same time reference is calculated, so as to achieve the purpose of real-time dynamic verification and calibration of the single-beam depth finder.

[0036] 1. A single-beam depth finder real-time dynamic verification device, mainly comprising: a single-arm travelling crane 1, a single-beam depth finder transducer 2, a GNSS device 6, and a sound velocity profiler 4.

[0037] Among them:

[0038] (1) The maximum allowable error of the sound velocity profiler is ±0.2 m / s;

[0039] (2) The single-arm travelling crane is provided with a single-beam depth finder transducer mounting connector, the maximum allowable error of the angle control is ±0.05°, the single-beam depth finder transducer can be installed and multi-dimensional control can be realized, the time synchronization system + servo motor can realize millisecond-level (50 ms) time synchronization, the single-arm travelling crane has a repeat positioning accuracy of 1 mm, and the real-time position thereof can be accurately obtained, and the running time and running distance thereof can be specified through the single-arm travelling crane control software;

[0040] 2. Dynamic verification method:

[0041] a) Install the single-beam depth finder to the single-arm travelling crane, so that it vertically emits sound waves to the standard surface, and the transducer has a water entry depth of 1 m;

[0042] b) Use the sound velocity meter to measure the sound velocity at 1 m under water along the running direction of the single-arm travelling crane (the long side wall of the pool) every 1 m, take the average, and input the single-beam depth finder;

[0043] c) Set the single-arm vehicle parameters (vehicle speed) to keep the initial position of the single-arm vehicle consistent, repeat the operation 10 times at the same speed, record the depth curve measured by the single-beam depth sounder each time and the single-arm vehicle operation position, and convert the single-arm vehicle operation position into the distance from the single-arm vehicle to the standard surface to obtain the single-arm vehicle distance curve;

[0044] d) Take the depth measured by the single-beam at 0.5s intervals as the reference for the first single-beam depth curve, and calculate the indication error of each time node of the second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth depth curves relative to the first depth curve;

[0045] e) Calculate the average value and standard deviation of the indication error of each time node for each operation to achieve the measurement stability evaluation of the single-beam depth sounder.

[0046] The average value and standard deviation of the indication error of each time node for each operation are calculated as follows:

[0047]

[0048]

[0049] In the formula: s j is the indication error of the time node corresponding to the second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth operation relative to the first single-beam depth value, j = 1, 2, 3… , is the number of time nodes, is the average value of the indication error of each node of the second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth operation, i = 2-10, is the standard deviation of the indication error of the time node corresponding to the second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth operation relative to the first single-beam depth value.

[0050] f) Take the single-arm vehicle distance curve as the reference (i.e. the true value: the distance between the single-arm vehicle with millimeter-level repeated positioning accuracy and the standard surface as the reference value), extract the depth measured by the single-beam at 0.5s intervals, and calculate the indication error of each time node of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth depth curve relative to the same single-arm vehicle distance curve;

[0051] g) Calculate the average value and standard deviation of the indication error at each time node to achieve the accuracy evaluation of the single-beam depth sounder.

[0052] The average value and standard deviation of the indication error of each node of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth depth curve relative to the same single-arm vehicle distance curve are calculated as follows.

[0053]

[0054]

[0055] In the formula: is the indication error of the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th run and the single-arm vehicle distance curve at each time node, j=1, 2, 3…m, m is the number of time nodes, is the average of the indication error of the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th run at each node, i=1~10. The standard deviation of the indication error of the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th single-beam depth sounder depth curve and single-arm vehicle distance curve at each node.

[0056] The positioning accuracy of the single-arm vehicle used in the application can reach 0.001 meters.

[0057] According to the method of the application, the HD-MAX depth sounder of Zhonghai can measure the water depth of 47m, and the maximum depth error is 0.04m; the 9-time standard deviations of the measurement stability evaluation are (0.012 0.019 0.012 0.012 0.008 0.018 0.012 0.013 0.012) (m), and the 10-time standard deviations of the accuracy evaluation are (0.009 0.006 0.012 0.007 0.007 0.010 0.011 0.007 0.009 0.007) (m). The accuracy evaluation conforms to the nominal accuracy (±1cm+0.1%h) of HD-MAX.

[0058] The key technical points of the application are:

[0059] (1) Real-time synchronization of single-arm vehicle time system and single-beam depth sounder time

[0060] The high-precision time reference provided by the GNSS device is used to realize the time synchronization of the single-arm vehicle time system and the single-beam depth sounder, and then the ranging value of the single-beam depth sounder and the real-time position of the single-arm vehicle at the same time are obtained, the position of the single-arm vehicle relative to the standard surface of the water tank is taken as the measurement reference value, and the ranging error of the single-beam depth sounder is calculated.

[0061] (2) Real-time dynamic calibration method.

Claims

1. A real-time dynamic calibration method for a single-beam echo sounder, comprising: (1) laying a straight travel guide along the bank of a pool, and movably positioning a single-arm travel crane on the guide; (2) setting a standard flat plate at one end of the pool, the plate vertically extending into the water and the plane of the plate being perpendicular to the straight travel guide; (3) measuring the sound speed in the water using a sound speed meter and inputting the single-beam echo sounder; (4) providing the single-beam echo sounder transducer on the single-arm travel crane, the transducer being submerged to a certain depth and emitting sound waves parallel to the straight travel guide towards the standard flat plate; (5) setting the parameters of the single-arm travel crane so that the initial position of the single-arm travel crane is consistent, repeatedly operating the single-arm travel crane 10 times at the same speed, recording the depth curve measured by the single-beam echo sounder and the operating position of the single-arm travel crane each time, converting the operating position of the single-arm travel crane into the horizontal distance from the single-arm travel crane to the standard flat plate, and obtaining the single-arm travel crane distance curve; (6) taking the depth measured by the single-beam echo sounder at intervals of 0.5 s based on the depth curve of the single-beam echo sounder in the first time, and calculating the indication error of each node of the depth curve in the second, third, fourth, fifth, sixth, seventh, eighth, ninth and tenth time with respect to the depth curve in the first time; (7) calculating the average value and standard deviation of the indication error at each time node of each operation to evaluate the measurement stability of the single-beam echo sounder; (8) taking the depth measured by the single-beam echo sounder at intervals of 0.5 s based on the single-arm travel crane distance curve, and calculating the indication error of each time node of the depth curve measured in the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth and tenth time with respect to the single-arm travel crane distance curve; (9) calculating the average value and standard deviation of the indication error at each time node to evaluate the accuracy of the single-beam echo sounder.

2. The real-time dynamic calibration method for a single-beam echo sounder according to claim 1, wherein the method for measuring the sound speed in the water using a sound speed meter in step (3) is that the sound speed meter runs along the travel guide, measures the sound speed at 1 m under water every 1 m, and takes the average sound speed value as the input of the single-beam echo sounder.

3. The real-time dynamic calibration method for a single-beam echo sounder according to claim 2, wherein the average value and standard deviation of the indication error at each time node of each operation in step (7) are calculated according to the following formulae, respectively:

4. The real-time dynamic calibration method for a single-beam echo sounder according to claim 3, wherein the average value and standard deviation of the indication error of each time node of the depth curve in the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth and tenth time with respect to the single-arm travel crane distance curve in step (9) are calculated according to the following formulae, respectively: ​ In the formula: is the standard deviation of the indication value error of the time node corresponding to the depth value of the single-beam depth sounder in the first run and the second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth runs, = 1, 2, 3,... , is the number of time nodes, is the mean value of the indication value error of each node in the second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth runs, i = 2-10, is the standard deviation of the indication value error of the time node corresponding to the depth value of the single-beam depth sounder in the first run and the second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth runs. ​ ​ In the formula: is the indication error of the single-beam echo sounder depth curve and the single-arm driving distance curve at each node of the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 10th runs, = 1, 2, 3,... is the number of nodes, is the average of the indication errors of each node of the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 10th runs, i = 1-10, is the standard deviation of the indication errors of each node of the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 10th single-beam echo sounder depth curves and single-arm driving distance curves.​

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