CN101587187B - Method for correcting deviation of depth measuring sonar system - Google Patents

Abstract

The invention provides a method for correcting the deviation of a sounding sonar system, comprising the following steps: 1) collecting data through an offshore calibration test to obtain the initial value of each parameter to be calibrated; 2) selecting a parameter to be calibrated, and according to each parameter to be calibrated 3) Judging whether the current correction amount of the selected parameter to be calibrated is less than the preset threshold value or converges to a certain value; if judged to be no, wait for The value of the calibration parameter is replaced by the sum of the current value of the parameter to be calibrated and the current correction amount, and returns to step 2), until the correction amounts of all the parameters to be calibrated meet the above determination conditions. The present invention comprehensively considers each calibration parameter in the system, utilizes a feedback mechanism, reduces the influence between the deviations of each system, and increases the accuracy of the deviation correction amount of each system. Simultaneously, the present invention considers various characteristics of the high-resolution depth-finding side-scan sonar, so it is particularly suitable for application to the high-resolution depth-finding side-scan sonar.

Description

A Deviation Correction Method for Depth Sounding Sonar System

technical field

The invention belongs to the technical field of sounding sonar, in particular, the invention relates to a deviation correction method of a sounding sonar system.

Background technique

At present, there are three types of sounding sonars commonly used, one is multi-beam sounding system, the other is high-resolution sounding side-scan sonar, and the third is interferometric synthetic aperture sonar. The multi-beam bathymetric system appeared earlier and has a wider range of applications; the high-resolution bathymetric side-scan sonar appeared later and is currently in the process of promotion; the interferometric synthetic aperture sonar system is the most complex and is currently in the process of development. Therefore, the following mainly introduces the first two types of sounding sonar.

A high-resolution bathymetric side-scan sonar is an acoustic device capable of detecting seafloor topography and landforms in high resolution. It is developed from the conventional sounding side-scan sonar, which uses two parallel receiving line arrays to estimate the arrival direction of the echo by measuring the delay between the two sonar arrays, thus obtaining The position of the ocean floor relative to the sonar array. The disadvantage of conventional sounding side-scan sonar is that it cannot measure multiple targets arriving at the sonar array at the same time, and the sounding accuracy directly below the sonar is poor.

The high-resolution sounding side-scan sonar solves the two problems of the conventional sounding side-scan sonar by adopting multiple parallel receiving line arrays with a half-wavelength spacing and using a dedicated signal processing algorithm, and expands its application range. Enhanced sonar usability.

Multi-beam sounding sonar forms multiple beams pointing in different directions, and then uses a certain signal processing method to estimate the arrival time delay of each beam's seabed echo, so as to obtain the position of the seabed relative to the sonar array. The sounding principle of the high-resolution sounding side-scan sonar is different from the traditional multi-beam sounding system. It directly estimates the direction of the echo arriving at the sonar array through a certain signal processing method for the echo signal with a known time delay. , so as to obtain the position of the seabed relative to the sonar array.

After these two types of sonars obtain the angle of incidence and time delay, they need to use the carrier position, carrier attitude, sound velocity profile, tide level and other data obtained by various sensors, as well as the spatial position relationship between the sonar array and various sensors on the carrier. Data, correct the parameters of the obtained time delay and incident angle, and finally deduce the latitude and longitude coordinates and steady-state depth of the measured seabed.

However, before the above work is actually carried out, in order to obtain higher-precision seabed depth and position data, it is necessary to use a certain system deviation correction method to obtain the deviation of the parameters that will cause system errors, so as to correct various parameters actually used .

There has been some research on the system deviation correction of multi-beam systems. Wu Ziyin and Jin Xianglong’s article "Comprehensive Correction of Edge Beam Errors in Multi-beam Bathymetry [J]. Oceanographic Journal, 2005, 27(4): 88-94." The correction method of the roll deviation angle before the survey and the correction method of the roll deviation angle on the basis of the surveyed data; Liu Shengxuan, Guan Yongxian's article "Multi-beam system parameter error judgment and correction [J].Ocean surveying and mapping , 2002, 22(1): 33-37." Proposed the same target detection method and section overlapping method for navigation and positioning delay correction and the actual measurement method and the same target detection method for yaw deviation correction; Li Wenjie, Hu Ping, Xiao Du , Liu Chunlei's article "Application of multi-beam bathymetry in marine engineering survey [J]. Geophysical and Geochemical Prospecting, 2004, 28(4): 373-376." proposed a linear target detection method for correcting yaw deviation; Liu Fanglan , Zhang Zhirong, Yu Ping's article "Correcting Method of Roll and Pitch Parameters of Multi-beam System [J]. Journal of Jilin University Earth Science Edition, 2004, 34(4): 621-624." Legal corrections for roll and pitch deviations.

The above-mentioned method has the following deficiencies and defects: 1) The essence of the above-mentioned system deviation correction method is to reduce the influence of other parameters as much as possible and highlight the influence of the calibrated parameters for deviation correction. But in fact, the sounding error is the result of the comprehensive influence of various parameters, so a single system deviation correction method can only remove the significant system deviation influence to a certain extent. 2) The above-mentioned system deviation correction method is based on multi-beam sounding sonar, and does not take into account the characteristics of other sounding sonars. For example, high-resolution sounding side-scan sonar has the following characteristics: First, high-resolution The main estimation parameter of depth-sounding side-scan sonar is the direction of arrival of the echo; second, high-resolution sounding side-scan sonar generally does not use beam stabilization technology; It will cause systematic deviation in calculating the angle of incidence; Fourth, a sonar array is used for the left and right sides of the high-resolution sounding side-scan sonar, and two sets of independent sonar array installation parameters are required. Therefore, the existing system deviation correction method is difficult to be directly used in high-resolution bathymetric side-scan sonar.

In order to improve the sounding accuracy of sounding sonar and make it more widely used, and considering the characteristics of high-resolution sounding side-scan sonar, a set of feasible system deviation correction methods is proposed.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, systematically and comprehensively process the deviations in yaw, roll, pitch, time delay, etc., so as to provide a sonar suitable for depth sounding, and especially suitable for high Practical system bias correction method for resolution bathymetric side-scan sonar.

In order to achieve the above-mentioned purpose of the invention, the method for correcting the deviation of the sounding sonar system provided by the present invention includes the following steps:

1) Collect data through offshore calibration tests to obtain the initial values of each parameter to be calibrated; the calibration parameters include at least roll deviation;

2) Select a parameter to be calibrated, and calculate the correction amount of the selected parameter to be calibrated according to the current value of each parameter to be calibrated;

3) Judging whether the current correction amount of the selected parameter to be calibrated is less than the preset threshold value or converges to a certain value; if it is judged to be yes, the current correction amount of the parameter to be calibrated is used as the final correction of the parameter to be calibrated If the judgment is no, the value of the parameter to be calibrated is replaced with the sum of the current value of the parameter to be calibrated and the current correction value, and returns to step 2);

4) When all the parameters to be calibrated have obtained the final correction value, the calibration process ends.

In the above technical solution, the parameters to be calibrated also include a systematic deviation of the incident angle.

In the above technical solution, the parameters to be calibrated also include yaw deviation.

In the above technical solution, the parameters to be calibrated also include a pitch deviation.

In the above technical solution, the parameter to be calibrated further includes positioning delay.

In the above technical solution, the depth-sounding sonar system is a high-resolution depth-sounding side-scan sonar system, and the roll deviation and the incident angle system deviation are corrected synchronously to obtain a comprehensive combination of the roll and incident angle system deviation. correction amount.

In the above technical solution, the calculation method of the comprehensive correction amount of the roll and incident angle system deviation is as follows:

a) During the offshore calibration test, sail along the predetermined survey line to collect sounding data; collect sound velocity profile data before and after the test;

b) Process the starboard sounding data and the port sounding data respectively to obtain the comprehensive correction value of starboard roll and incident angle system deviation and the comprehensive correction value of port roll and incident angle system deviation respectively. The processing method of the sounding data is as follows :

b1) For the i-th frame of bathymetry data, read the arrival time of the scattering signal directly below, and then calculate the depth d directly below according to the sound velocity profile data;

b2) Under the assumption that the depth of each sounding point is equal to d, the theoretical incidence angle θ' corresponding to each time delay τ in the starboard data of the i-th frame is calculated by fitting;

b3) Calculate the difference Δ i (θ) between the actual angle of incidence θ corresponding to each time delay τ directly read in _the i-th frame of bathymetric data and its corresponding theoretical angle of incidence θ′, and the difference Δ _i (θ) is used as the comprehensive correction value of the roll and incident angle system deviation of the i-th frame;

b4) Calculate the average value Δ(θ) of the comprehensive corrections of roll and incident angle system deviations of all frames on a single track;

b5) According to the average slope in the vertical track direction and the average value of the comprehensive corrections of roll and incident angle system deviations calculated on different tracks, the corrected comprehensive corrections of roll and incident angle system deviations are obtained.

In the above technical solution, the calibration parameters also include the motion sensor output delay deviation, and the method for obtaining the correction amount of the motion sensor output delay deviation is as follows:

c1) Take a section of bathymetric data obtained in a flat area as the corrected original data;

c2) Substituting the correction amount of the existing system calibration parameters, calculating the depth and position according to the original data, fitting and calculating the slope of the bathymetry data obtained by each launch, and taking the slope r _i of the i-th frame data;

c3) Read the roll R _i and time T _i of each frame to obtain R _i (T _i );

c4) Calculate the roll deviation of each frame due to the delay of the motion sensor output:

Δ _i R(τ ₀ )＝R _i (T _i -τ ₀ )-R _i (T _i )

最小的τ₀为最终运动传感器延时修正量。Select the optimal τ ₀ value according to the minimum mean square error criterion, so that

The smallest τ ₀ is the final motion sensor delay correction.

In the above technical solution, in the step 2), firstly, the severity of the deviation of each parameter to be calibrated is sorted to obtain the priority of correcting each parameter to be calibrated, and then each parameter to be calibrated is selected in sequence according to the priority to correct The correction amount of each parameter to be calibrated is calculated.

In the above technical solution, in the step 2), the order of selecting the parameters to be calibrated is as follows: yaw deviation, pitch deviation, positioning delay, roll deviation and incident angle system deviation.

Compared with prior art, the beneficial effect of the present invention is:

(1) The system deviation correction method of the present invention has considered the characteristics of high-resolution sounding side-scan sonar, so it is particularly suitable for being applied to high-resolution sounding side-scan sonar; but the present invention can also be used for conventional sounding The parameters of sonar such as deep side scan sonar, multibeam sounding system and interferometric synthetic aperture sonar are being corrected.

(2) The system deviation correction method of the present invention proposes a comprehensive correction method for roll and incident angle system deviation aimed at the characteristics of high-resolution sounding side-scan sonar; this method can also be used for conventional sounding side-scan sonar, multiple The parameters of sonar such as beam sounding system and interferometric synthetic aperture sonar are being corrected. .

(3) The system deviation correction method of the present invention proposes a motion sensor delay correction method for sounding sonar.

(4) The system deviation correction amount obtained in each step of the system deviation correction method of the present invention will be substituted into the next step of data processing, and the finally obtained roll and incident angle system deviation correction amount will be substituted into the first yaw data after correction Processing is performed again during the processing to form feedback, thereby increasing the accuracy of the deviation correction amount of each system.

Description of drawings

Hereinafter, embodiments of the present invention will be described in detail in conjunction with the accompanying drawings, wherein:

Figure 1 is the flat area survey line;

Fig. 2 is a flow chart of the system deviation correction method of the present invention;

Fig. 3 is the comparative schematic diagram of bathymetric charts before and after using the system deviation correction of the present invention; line graph); both use the same scale;

Fig. 4 is a comparison diagram of depth error before and after system deviation correction using the present invention, the left figure is the depth error figure before system deviation correction, and the right figure is the depth error figure after system deviation correction. Both graphs use the same scale;

Figure 5 is a schematic diagram of terrain changes caused by roll deviation.

Detailed ways

Basic idea of the present invention is as follows:

Since all the parameters that need to be corrected in the depth sounding sonar system are mutually affected and interacted during the parameter correction process, the correction method for a single parameter cannot exclude the influence of other parameter deviations, thus bringing new errors. Therefore, the present invention proposes a method for cyclic data processing, the principle of which is to substitute the system deviation correction amount obtained in each step into the data processing in the next step, and substitute the system deviation correction amount obtained at the end into the first system deviation data correction post-processing Process again to form feedback. The purpose of the feedback is to reduce the influence among the system deviations again, and the termination condition of the feedback is that the change value of the correction amount of each system deviation reaches a preset threshold value or converges to a certain value.

Example 1

After the high-resolution bathymetric side-scan sonar obtains the incident angle and time delay, it also needs to use various sensors to obtain carrier position, carrier attitude, sound velocity profile, tide level and other data, as well as sonar arrays and various sensors on the carrier. The spatial position relationship data of the obtained time delay and incident angle are corrected, and finally the latitude and longitude coordinates and steady-state depth of the measured seabed are derived. Table 1 is a list of the main parameters affecting the error of high-resolution bathymetric side-scan sonar.

Table 1

It can be seen from Table 1 that according to its own characteristics, the deviation correction required by the system mainly includes the following aspects: fine measurement of the relative distance between the positioning system antenna, motion sensor and sonar array; Installation deviation correction of tilt and roll; positioning delay correction and incident angle system deviation correction caused by inconsistency of sonar channels.

This embodiment is mainly to comprehensively correct yaw, pitch, roll (only consider the roll deviation caused by installation) and positioning delay. The steps are as follows:

Step 1: When the system is installed, finely measure the relative distance between the antenna of the positioning system, the motion sensor and the sonar array, and record these data as parameters in the subsequent data processing.

Step 2: Perform sea calibration experiments. Firstly, the data needed for yaw correction, pitch correction and positioning delay correction are obtained according to conventional methods. Select an isolated target, sail straight on one side of it, use the edge beam to measure the target, and get a data file; sail in the opposite direction on the other side of the target, use the edge beam of the same sonar array to measure the marker, and get another Data file to obtain the data required for yaw correction. Find a sea area with a slope, measure back and forth along a survey line perpendicular to the isobath, try to keep the speed constant, and obtain the data required for trim correction. Change the speed and sail in a straight line repeatedly in the same direction directly above the target to obtain the data required for positioning delay correction. Then select an area that is as flat as possible to measure to obtain the data required for roll correction. Use the survey line shown in Figure 1. The length of the survey line is the maximum coverage on both sides of the sonar, and the interval between the survey lines is the maximum coverage of a single measurement. . Before and after the calibration test, a sound velocity profiler should be used to detect the sound velocity profile of the test water area, and the measured sonar profile value will be used in steps 3 and 4.

Step 3: Perform post-processing of yaw, pitch and positioning delay correction data. First, the preliminary sounding results are calculated from the yaw correction data to obtain the yaw correction value, then the yaw value in the pitch correction data is corrected, and the pitch correction value is obtained through processing, and finally the yaw correction value and the pitch correction value are substituted into Positioning delay correction data to obtain the value of positioning delay. The data of the two sonar arrays are processed separately in the post-processing of the yaw and pitch correction data.

The post-processing of the yaw, pitch and positioning delay correction data in this step can refer to "Correction method of roll deviation and pitch deviation: Liu Fanglan, Zhang Zhirong, Yu Ping, Correction method of roll and pitch parameters of multi-beam system [J ]. Jilin University Journal of Earth Sciences, 2004, 34(4): 621-624." and "Navigation positioning delay correction method and yaw deviation correction method: Liu Shengxuan, Guan Yongxian, multi-beam system parameter error judgment and correction[ J]. Oceanographic Mapping, 2002, 22(1): 33-37."

Step 4: Perform roll correction data post-processing. Incorporate corrections such as yaw deviation, pitch deviation and positioning delay, use the detection data in flat areas and use the fitting algorithm to obtain roll system deviation corrections, and use the sonar array on the same side to measure the rolling of the same area multiple times The consistency of the value is used as the criterion for judging whether the correction amount is correct. The roll correction should be carried out separately for the starboard and starboard sides.

For the post-processing of roll correction data in this step, please refer to "Correction method of roll deviation and pitch deviation: Liu Fanglan, Zhang Zhirong, Yu Ping, Correction method of roll and pitch parameters of multi-beam system [J]. Journal of Jilin University Earth Science Edition, 2004, 34(4): 621-624." and "Correction Method for Rolling Deviation: Wu Ziyin, Jin Xianglong, Comprehensive Correction of Edge Beam Errors in Multi-beam Bathymetry [J]. Oceanographic Journal, 2005, 27(4 ): 88-94".

Step 5: Substitute the roll deviation correction into step 3 to replace the original roll data, and then follow the method in step 3 to calculate the new yaw deviation, pitch deviation and positioning delay correction in turn. Then substitute the new yaw deviation, pitch deviation and positioning delay correction into step 4, and calculate the roll deviation correction again. The above-mentioned iterative calculation process is repeated until the variation of the yaw deviation, the pitch deviation, the positioning delay and the roll deviation correction amount are all less than the preset threshold value or converge to a certain value. Of course, the criterion for stopping the iterative calculation here may also be that the variation of one or more parameter corrections is less than a preset threshold or converges to a certain value, which is easily understood by those skilled in the art.

Specifically, in this step, it is first judged whether the current correction amount of the selected parameter to be calibrated (such as the current value of the roll deviation correction amount) is less than a preset threshold value or converges to a certain value; if it is judged to be , then take the current correction amount of the parameter to be calibrated as the final correction amount of the parameter to be calibrated; roll deviation value) and the current correction amount (that is, the current roll deviation correction value), and then substitute the value of the new parameter to be calibrated (that is, the new roll deviation value) into step 3, and recalculate the other The correction of the parameters to be calibrated (such as yaw deviation, pitch deviation and positioning delay correction); in this way, iteratively calculate and update each parameter to be calibrated (including yaw deviation, pitch deviation, positioning delay and roll deviation) The correction amount until all the parameters to be calibrated meet the above judgment conditions, so as to obtain the final correction amount.

Step 6: Select the cross survey line at sea to carry out the internal coincidence test, use the obtained corrections to calibrate the corresponding parameters, and process the obtained bathymetry results for internal coincidence evaluation to test the effect of system deviation correction.

The analysis of the internal coincidence evaluation results shows that the error of 96.6% of all the sounding points is less than 0.2712 meters, and the measurement accuracy exceeds the IHO first-class standard. The deviation correction method of the high-resolution bathymetric side-scan sonar system proposed by the invention has passed the verification of test data, and can obtain high-precision bathymetric maps.

Example 2

Steps 1 to 3 and Steps 5 and 6 of this embodiment are consistent with Embodiment 1, the difference is that in order to obtain more accurate deviation correction data, Step 4 of this embodiment takes into account the incidence caused by the inconsistency of the sonar channel Angle system deviation, correct the roll and incident angle system deviation at the same time. The principle and implementation steps of Step 4 of this embodiment will be described in detail below.

For high-resolution bathymetric side-scan sonar, due to the inconsistency between channels, the incident angle obtained after signal processing has a fixed deviation. Its size changes with the value of θ, and it will have a larger value when the value of θ is in a certain range. This deviation appears on the bathymetric chart as a ditch-like or ridge-like pseudo-terrain parallel to the track direction. Due to the existence of the incident angle system deviation, the calculation of the average slope in the vertical track direction of the seabed in the actual measurement method has a large error, and the simple adjustment of the roll angle cannot make the profiles overlap. Therefore, the influence of roll installation deviation and incident angle deviation on depth and position is superimposed, and their correction must be completed at the same time, which is called comprehensive correction of roll and incident angle system deviation.

Roll and incident angle system deviation is comprehensively corrected, and the correction test is carried out on a flat seabed to collect data. A certain fitting algorithm is used to obtain the correction amount of the roll installation deviation and the incident angle system deviation, and the multiple measured values of the same side of the sonar array to the same area after roll and incident angle correction are as consistent as possible as the judgment correction amount correctness criterion. The comprehensive correction of roll and incident angle system deviation should be carried out separately for starboard and starboard.

Use the measuring line shown in the figure above to collect data in a flat area. The length of the measuring line is the maximum coverage of both sides of the sonar, and the distance between the measuring lines is the maximum coverage of a single measurement.

In actual work, the following steps are used to obtain the comprehensive correction value of roll and incident angle system deviation:

1. Navigate along the surveying line shown in Figure 1, collect sounding data, take the starboard sounding data of AB section and CD section as the original data for comprehensive correction of starboard roll and incident angle system deviation, and the port side sounding data of CD section and EF section The deep data is used as the raw data for the comprehensive correction of system deviation of port roll and incident angle. The sound velocity profile data should be collected before and after the test.

2. Take the starboard sounding data of section AB for processing. Take the starboard sounding data obtained from one launch (assuming it is the i-th frame of starboard sounding data), read the arrival time of the scattered signal directly below, and then calculate the depth d directly below according to the sound velocity profile data.

3. Under the assumption that the depth of each sounding point is equal to d, the theoretical incidence angle θ' corresponding to each time delay τ in the starboard data of the i-th frame is fitted. The fitting algorithm uses various depth-sounding parameters and sound velocity profiles to calculate according to the formula of the sound ray tracing method. After layer-by-layer recursion, until the depth is equal to d, the theoretical incidence angle θ′ corresponding to each time delay τ is finally obtained.

4. The actual angle of incidence θ corresponding to each time delay τ (that is, the angle of incidence θ read in the starboard data of the i-th frame) and its corresponding theoretical angle of incidence θ′ (that is, the angle of incidence obtained by fitting in step 3 θ′) The difference Δ _i (θ) is the comprehensive correction amount of starboard roll and incident angle system deviation in the i-th frame.

5. Calculate Δ _n (θ) for each frame of starboard sounding data in AB section, and calculate their average value Δ(θ).

得到右舷横摇和入射角系统偏差综合修正量。6. Considering that the seabed generally has a certain inherent inclination, Δ(θ) is substituted into the parameter correction formula, and the depth and position are calculated according to the starboard sounding data of the CD section, and then the average slope β in the vertical track direction is obtained, Δ(θ) minus

Obtain the comprehensive correction value of starboard roll and incident angle system deviation.

7. Fine-tune the comprehensive correction value of starboard roll and incident angle system deviation until the starboard sounding results of section AB and section CD are as consistent as possible.

8. Referring to the above steps 2 to 7, do the same processing on the port sounding data of the CD segment and EF segment to obtain the comprehensive correction value of the system deviation of the port roll and incident angle.

Example 3

This embodiment is based on Embodiment 2, and further considers the output delay of the motion sensor, so as to perform more accurate correction of each system deviation.

In addition to installation deviations, roll, pitch and yaw angles also have deviations caused by motion sensor output delays. This deviation can be corrected by using a certain method to obtain the output delay of the motion sensor. Generally, the output delay of the motion sensor is a fixed system parameter, which is given by the motion sensor manufacturer. However, in actual work, due to the delay of data transmission or computer processing data, the actual output delay of the motion sensor does not match the value given by the manufacturer. The measurement of this value is relatively difficult. In this paper, the output delay correction of the motion sensor is performed through data post-processing. The principle is that it can be proved geometrically that the slope of a certain frame is equal to the roll deviation of this frame for the bathymetry results of a flat area. The specific correction method is as follows:

1. Take a piece of bathymetry data obtained in a flat area as the original data for correction;

2. Substituting the existing system deviation correction amount into the parameter correction formula, calculating the depth and position according to the original data, and then fitting the slope r _i of the bathymetry data (assumed to be the i-th frame data) obtained by each launch;

3. Read the roll R _i and time T _i of each frame, they are in one-to-one correspondence, and get R _i (T _i );

4. Calculate the roll deviation of each frame due to the output delay of the motion sensor by the following formula:

Δ _i R(τ ₀ )＝R _i (T _i -τ ₀ )-R _i (T _i )

最小的τ₀为最终运动传感器延时修正量。Select the optimal τ ₀ value according to the minimum mean square error criterion, that is, take such that

The smallest τ ₀ is the final motion sensor delay correction.

In this embodiment, the motion sensor delay correction amount is substituted into the calculation of step 4 (i.e., the step of post-processing the roll correction data in embodiment 1), so as to improve the comprehensive correction of roll and incident angle system deviation. accuracy.

In addition, since the delay of the motion sensor will also have a certain impact on the pitch and yaw deviation, it is also possible to perform the post-processing of the yaw, pitch, and positioning delay correction data in the third step (i.e., in Embodiment 1) ) is substituted into the motion sensor delay correction amount.

Example 4

The difference between this embodiment and the first three embodiments lies in the selection of the order of deviation correction of each parameter, and the rest is consistent with Embodiment 1, 2 or 3. The steps of this embodiment are as follows:

Step 1: When the system is installed, measure the relative distance between the antenna of the positioning system, the motion sensor and the sonar array as accurately as possible to reduce the system deviation caused by the relative distance.

Step 2: Perform sea calibration experiments. The calibration test consists of two parts: one is to obtain the data required for yaw correction, pitch correction and positioning delay correction according to the conventional method; the other is to select an area as flat as possible for measurement to obtain the data required for roll and incident angle system deviation correction , using the measuring line shown in Figure 1, the length of the measuring line is the maximum coverage of both sides of the sonar, and the distance between the measuring lines is the maximum coverage of a single measurement. Before and after the calibration test, a sound velocity profiler should be used to detect the sound velocity profile of the test water area.

Step 3: Correct the parameters of the test data to obtain preliminary sounding results. The preliminary sounding results are analyzed, and the severity of each system parameter deviation is sorted according to the impact on the sounding results, so as to obtain the priority of correcting each system parameter deviation. The system parameters that need to be prioritized here include at least yaw, pitch, positioning delay and roll.

Step 4: According to the priorities of correcting the deviations of the various system parameters, post-processing the correction data is performed sequentially in order of priorities from high to low to obtain their correction amounts. The system parameter deviation correction amount obtained in each step shall be substituted into the data processing of the system parameter deviation with lower priority in the next step.

Step 5: Substitute the correction amount of the system parameter deviation with the lowest priority obtained in step 4 into the data processing of the deviation correction amount of the system parameter with the highest priority, and perform step 4 again, in order of priority from high to low The correction data is post-processed sequentially to obtain the deviation correction amount of each system parameter and obtain a more accurate system deviation correction amount. The above process is repeated in this way until the variation of each parameter is smaller than the preset threshold value or converges to a certain value.

Step 6: Select the cross-crossing survey line at sea to conduct internal coincidence evaluation test, correct the system deviation with the obtained deviation correction amount of each system, perform parameter correction and internal coincidence evaluation, and test the effect of system deviation correction.

The specific embodiments described above have described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above content is only a specific embodiment of the present invention, and is not intended to limit the present invention. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. A method for correcting deviation of a sounding sonar system, comprising the steps of: 1) Select several items in roll deviation, incident angle system deviation, yaw deviation, pitch deviation, and positioning delay as parameters to be calibrated, and the parameters to be calibrated include at least roll deviation; data are collected through offshore calibration tests , to obtain the initial value of each parameter to be calibrated; 2) Select a parameter to be calibrated, and calculate the correction amount of the selected parameter to be calibrated according to the current value of each parameter to be calibrated; 3) Judging whether the current correction amount of the selected parameter to be calibrated is less than the preset threshold value or converges to a certain value; if it is judged to be yes, the current correction amount of the parameter to be calibrated is used as the final correction of the parameter to be calibrated If the judgment is no, the value of the parameter to be calibrated is replaced with the sum of the current value of the parameter to be calibrated and the current correction value, and returns to step 2); 4) When all the parameters to be calibrated get the final correction amount, the calibration process ends; Wherein, in the step 2), the roll deviation and the incident angle system deviation are corrected synchronously to obtain the comprehensive correction amount of the roll and incident angle system deviation; the comprehensive correction of the roll and incident angle system deviation The calculation of the quantity includes the steps: a) During the offshore calibration test, sail along the predetermined survey line to collect sounding data; collect sound velocity profile data before and after the test; b) Process the starboard sounding data and the port sounding data respectively to obtain the comprehensive correction value of starboard roll and incident angle system deviation and the comprehensive correction value of port roll and incident angle system deviation respectively. The processing method of the sounding data is as follows : b1) For the i-th frame of bathymetry data, read the arrival time of the scattering signal directly below, and then calculate the depth d directly below according to the sound velocity profile data; b2) Under the assumption that the depth of each sounding point is equal to d, the theoretical incidence angle θ' corresponding to each time delay τ in the starboard data of the i-th frame is calculated by fitting; b3) Calculate the difference Δ i (θ) between the actual angle of incidence θ corresponding to each time delay τ directly read in _the i-th frame of bathymetric data and its corresponding theoretical angle of incidence θ′, and the difference Δ _i (θ) is used as the comprehensive correction value of the roll and incident angle system deviation of the i-th frame; b4) Calculate the average value Δ(θ) of the comprehensive corrections of roll and incident angle system deviations of all frames on a single track; b5) According to the average slope in the vertical track direction and the average value of the comprehensive corrections of roll and incident angle system deviations calculated on different tracks, the corrected comprehensive corrections of roll and incident angle system deviations are obtained. 2. The method for correcting the deviation of the sounding sonar system according to claim 1, wherein the sounding sonar system is a high-resolution sounding sonar system. 3. The method for correcting the deviation of the sounding sonar system according to claim 1, wherein the calibration parameter also includes a motion sensor output delay deviation, and obtains a calculation method for the correction amount of the motion sensor output delay deviation as follows: c1) Take a section of bathymetric data obtained in a flat area as the corrected original data; c2) Substituting the correction amount of the existing system calibration parameters, calculating the depth and position according to the original data, fitting and calculating the slope of the bathymetry data obtained by each launch, and recording the slope of the i-th frame of bathymetry data as r _i ; c3) Read the roll R _i and time T _i of each frame to obtain R _i (T _i ); c4) Calculate the roll deviation of each frame due to the delay of the motion sensor output: Δ _i R(τ ₀ )＝R _i (T _i -τ ₀ )-R _i (T _i ) Select the optimal τ ₀ value according to the minimum mean square error criterion, so that

The smallest τ ₀ is the final motion sensor delay correction. 4. the sounding sonar system deviation correcting method according to claim 1, it is characterized in that, in described step 2), at first the seriousness of the deviation of each parameter to be calibrated is sorted, draws each parameter to be calibrated The priority of calibration, and then select the parameters to be calibrated in order according to the priority to calculate the correction amount of each parameter to be calibrated. 5. the sounding sonar system deviation correction method according to claim 1, is characterized in that, in described step 2), the order of selecting each parameter to be calibrated is successively: yaw deviation, pitch deviation, positioning delay, Roll bias and incident angle system bias.

Images