Statistical difference-based ultra-short baseline positioning method

Abstract

The application relates to an ultra-short baseline positioning method based on statistical difference, and relates to the field of ocean engineering. The application is used to solve the problems of small effective positioning range of the existing ultra-short baseline underwater acoustic positioning system and low positioning precision when high-precision sound velocity information is lacked. The application comprises the following steps: obtaining a slant range R T of a positioning target, a coarse measurement result cos theta T and a coarse positioning result X T ; obtaining horizontal position utilization of a difference reference station in a base array coordinate system and X T ; obtaining a reference station I with the best positioning effect; obtaining a true slant range direction angle and a direct difference correction (Delta x, Delta y) T by using the geodetic coordinates of the reference station I; obtaining a positioning target relative difference correction coordinate X=(x, y) T in the base array coordinate system by using X T , R T and (Delta x, Delta y) T ; and converting X=(x, y) T into geodetic coordinates by using a conversion matrix from the base array coordinate system to the geodetic coordinate system, so as to obtain geodetic coordinates of the positioning target. The application is used for positioning a target by using an ultra-short baseline underwater acoustic positioning system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ocean engineering, in particular to an ultra-short baseline positioning method based on statistical difference. BACKGROUND

[0002] The current underwater acoustic positioning technology is divided into three types: long baseline underwater acoustic positioning technology, short baseline underwater acoustic positioning technology and ultra-short baseline underwater acoustic positioning technology. The baseline length of the long baseline underwater acoustic positioning system is generally several kilometers to tens of kilometers, and the position of the target is determined by measuring the distance between the underwater target sound source and each element. The baseline length of the short baseline underwater acoustic positioning system is generally several meters to tens of meters, and the target direction and distance are obtained by using the time difference of the signal reaching each element of the receiving needle. The baseline length of the ultra-short baseline underwater acoustic positioning system is generally several centimeters to tens of centimeters, and the target direction is calculated by calculating the time delay difference of the sound array receiving target signal, and the target position is calculated by combining the ranging information.

[0003] The time delay difference of the current ultra-short baseline underwater acoustic positioning system is related to the opening angle of the target relative to the baseline at that time, which leads to the decrease of the positioning accuracy with the increase of the opening angle, and affects the effective range of the positioning system. In addition, the ultra-short baseline underwater acoustic positioning system currently relies on high-precision sound velocity information obtained by sound velocity profiler, CTD sensor and other devices, and when the platform volume, cost and other factors are limited, the positioning accuracy will be low. SUMMARY

[0004] The present application aims to solve the problems of small effective positioning range of the existing ultra-short baseline underwater acoustic positioning system and low positioning accuracy when lacking high-precision sound velocity information, and proposes an ultra-short baseline positioning method based on statistical difference.

[0005] The specific process of an ultra-short baseline positioning method based on statistical difference is as follows:

[0006] Step one, laying out difference reference stations on the seabed, calibrating the difference reference stations, and obtaining the geodetic coordinates of the difference reference stations

[0007]

[0008] Wherein, l is the label of the reference station, and m is the number of laid reference stations.

[0009] Step two, positioning the positioning target to obtain the slant range R of the positioning target T , the coarse measurement result cosθ of the positioning target T , and the coarse positioning result X of the positioning target T .

[0010] Step three, obtaining the horizontal position of each difference reference station in the baseline coordinate system Using X obtained in step two T Obtaining the reference station I which has the best differential positioning effect on the current positioning target

[0011] Step four, using the geodetic coordinates of the reference station I Obtaining the true slant range of the reference station I Direction angle And direct difference correction (Δx, Δy) T ;

[0012] Step five, using the rough positioning result X of the positioning target obtained in step two T , the slant range R of the positioning target T , the rough direction finding result cosθ of the positioning target T , the slant range of the reference station I obtained in step four Direction angle And direct difference correction (Δx, Δy) T Obtaining the relative difference correction coordinates X = (x, y) of the positioning target in the base array coordinate system T ;

[0013] Step six, using the conversion matrix from the base array coordinate system to the geodetic coordinate system Convert X = (x, y) T to geodetic coordinates, thereby obtaining the geodetic coordinates of the positioning target.

[0014] Further, the positioning of the positioning target in step two to obtain the slant range R of the positioning target T , the rough direction finding result cosθ of the positioning target T And the rough positioning result X of the positioning target T , includes the following steps:

[0015] Step two one, obtaining the slant range from the base array to the positioning target The direction angle from the base array to the positioning target The coordinates of the positioning target in the base array coordinate system n is the total number of measurements;

[0016] Step two two, taking the average value of the slant range from the base array to the positioning target in multiple measurements as the slant range of the positioning target:

[0017]

[0018] Step two three, taking the average value of the direction angle from the base array to the positioning target in multiple measurements as the rough direction finding result cosθ of the positioning target T = (cosθ Tx , cosθ Ty ) T :

[0019]

[0020] Step two, average the coordinates of the positioning target in the base array coordinate system in multiple measurements as the coarse positioning result of the positioning target:

[0021]

[0022] Wherein, the coarse positioning result is

[0023] Wherein, R T The slant range of the positioning target, C is the sound speed, d is the array element interval, The time delay difference of the x direction of the base array coordinate system in the i-th statistics, The time delay difference of the y direction of the base array coordinate system in the i-th statistics.

[0024] Further, the real horizontal position of the differential reference station in the base array coordinate system in step three Using And the coarse positioning result X of the positioning target obtained in step two T Obtain the reference station I which is best for differential positioning of the current positioning target, as follows:

[0025]

[0026] Wherein, I is the reference station number which is best for differential positioning, The real horizontal position of the reference station in the base array coordinate system.

[0027] Further, the geodetic coordinates of the reference station I in step four Obtain the real slant range of the reference station I The direction angle And the direct difference correction (Δx, Δy) T , comprising the following steps:

[0028] Step four, obtain the base array geodetic coordinates X jz =(x jz ,y jz ,z jz ) T , combined with the geodetic coordinates of the reference station I Obtain the real slant range of the reference station I

[0029]

[0030] Step four, obtain the real coordinates of the reference station I in the base array coordinate system According to the real slant range of the reference station I and Obtaining the horizontal direction angle of reference station I

[0031] Step four three, positioning the labeled reference station n times to obtain the coordinates of reference station I in the base array coordinate system Obtaining the average coordinates of the coordinates of reference station I in the base array coordinate system in n times of measurement

[0032] Step four four, using the coordinates obtained in step four three and the true coordinates of reference station I in the base array coordinate system Obtaining the direct difference correction (Δx, Δy) of reference station I T ;

[0033] Where Δx is the direct difference correction of reference station I in the x direction, and Δy is the direct difference correction of reference station I in the y direction.

[0034] Further, the horizontal direction angle of reference station I in step four two Specifically as follows:

[0035]

[0036]

[0037] Where, is the conversion matrix from the true geodetic coordinate system to the true base array coordinate system.

[0038] Further, the average coordinates of the coordinates of reference station I in the base array coordinate system in n times of measurement in step four three As follows:

[0039]

[0040] Further, the direct difference correction (Δx, Δy) of reference station I in step four four T , specifically as follows:

[0041]

[0042] Further, the relative difference correction coordinates X = (x, y) of the positioning target in the base array coordinate system in step five T , specifically as follows:

[0043]

[0044] Further, the conversion matrix from the base array coordinate system to the geodetic coordinate system in step six X = (x, y) TConvert to geodetic coordinates, as follows:

[0045]

[0046] The beneficial effects of the present application are:

[0047] The present application provides a statistical difference-based ultra-short baseline positioning method, which includes two parts of coarse positioning and difference positioning of a target. First, the target is positioned by using an ultra-short baseline system to obtain a coarse positioning result, then the difference information is obtained by positioning the calibrated reference station by the ultra-short baseline positioning, and finally the high-precision positioning result of the positioning target is obtained by combining the coarse positioning information and the difference information for difference correction. The present application can effectively improve the positioning accuracy of the ultra-short baseline positioning system under the premise of lacking high-precision sound velocity information, and can expand the effective range of positioning under the condition of reasonable reference station layout, so that the positioning accuracy in the task range remains high consistency. BRIEF DESCRIPTION OF DRAWINGS

[0048] Fig. 1 The flowchart of the implementation of the ultra-short baseline difference positioning;

[0049] Fig. 2 The schematic diagram of the application scenario of the ultra-short baseline difference positioning;

[0050] It includes a reference station, a target and a ship loaded with an ultra-short baseline array;

[0051] Fig. 3 The plane schematic diagram of the application scenario of the ultra-short baseline difference positioning. DETAILED DESCRIPTION

[0052] Specific implementation one: as shown in the figure, the specific process of the present embodiment of the statistical difference-based ultra-short baseline positioning method is: Figs. 1-3

[0053] Step one, according to the operation area, the difference reference station is laid on the seabed, the difference reference station is calibrated, and the accurate geodetic coordinates of the difference reference station are obtained Wherein, l is the label of the reference station, and m is the number of laid reference stations;

[0054] Step two, the ship loaded with the ultra-short baseline system positions the positioning target loaded with the transponder, obtains the slant range of the positioning target, the coarse measurement result of the positioning target and the coarse positioning result of the positioning target, including the following steps:

[0055] Step two, the geodetic position, heading, attitude, and array-to-positioning target slant range of the ship loaded with the ultra-short baseline system are obtained The direction angle of the array to the positioning target The coordinates of the positioning target in the array coordinate system n is the total number of measurements;​

[0056] wherein, is the x-axis coordinate of the positioning target in the base array coordinate system, is the y-axis coordinate of the positioning target in the base array coordinate system, is the x-axis directional component of the base array to the positioning target, is the y-axis directional component of the base array to the positioning target;

[0057] Step two, the average value of the slant range of the base array to the positioning target in multiple measurements is taken as the slant range of the positioning target:

[0058]

[0059] Step two, the average value of the directional angle of the base array to the positioning target in multiple measurements is taken as the coarse measurement result cosθ of the positioning target: T = (cosθ Tx , cosθ Ty ) T :

[0060]

[0061] Step two, the average value of the coordinates of the positioning target in the base array coordinate system in multiple measurements is taken as the coarse positioning result of the positioning target:

[0062]

[0063] According to the time delay information received by the ultra-short baseline base array, combined with the principle of ultra-short baseline acoustic positioning, the base array coordinates of the positioning target are:

[0064]

[0065] wherein, R T is the slant range of the positioning target, C is the sound speed used in the positioning process, τ is the time delay difference of the array elements in the base array coordinate system, d is the array element spacing, is the time delay difference of the array elements in the x direction of the base array coordinate system in the i-th statistics, is the time delay difference of the array elements in the y direction of the base array coordinate system in the i-th statistics.

[0066] Step three, the real horizontal position of the differential reference station in the base array coordinate system is obtained using and the coarse positioning result X T of the positioning target obtained in step two, the reference station I with the best differential positioning effect for the current positioning target is obtained:

[0067] The real horizontal positions of the reference stations in the current base array coordinate system are calculated according to the current geodetic position and attitude of the ship equipped with the ultra-short baseline system The ratio of coordinates is Where I is the index of different reference stations; the target coarse positioning array coordinates are X T = (x T , y T ) T The ratio of coordinates is The criterion of reference station is:

[0068] According to the method characteristics, the differential effect is symmetrical about the origin in the array coordinate system with the array center as the origin, so the selection of the reference array is based on the proximity of the azimuth of the target and the reference array, that is:

[0069]

[0070] Where I is the index of the reference station with the best differential positioning effect, is the real horizontal position of the reference station in the array coordinate system.

[0071] Step four, the real geodetic coordinates of the reference station I Get the real slant range, horizontal direction angle and direct differential correction of the reference station I:

[0072] Step four, according to the GPS of the ship and the installation position of the array, get the real geodetic coordinates X jz = (x jz , y jz , z jz ) T , and combine the real geodetic coordinates of the reference station I Get the real slant range of the reference station I:

[0073]

[0074] Step four, according to the GPS of the ship and the installation position of the array, get the real geodetic coordinates X Get the horizontal direction angle of the reference station I according to the real slant range of the reference station I and

[0075]

[0076]

[0077] Where, is the coordinate of the reference station I in the array coordinate system, is the conversion matrix from the real geodetic coordinate system to the real array coordinate system;

[0078] ​Step 4.3: The ship equipped with the ultra-short baseline system performs n positioning operations on the reference station to obtain the coordinates of reference station I in the matrix coordinate system. Take its average coordinates as its solution coordinates:

[0079]

[0080] Step 44: Based on the solved coordinates obtained in Step 43 and the true coordinates of base station I in the matrix coordinate system, obtain the direct difference correction for base station I:

[0081]

[0082] Where Δx is the direct differential correction in the Ix direction of the reference station, and Δy is the direct differential correction in the Iy direction of the reference station.

[0083] Step 5: Utilize the coarse positioning result X of the target obtained in Step 2. T =(x T ,y T ) T Target slant range R T Coarse direction finding results for locating the target (cosθ) Tx cosθ Ty ) T The slant distance of base station I obtained in step four Direction angle And direct difference correction (Δx, Δy) T Obtain the relative differential correction coordinates X = (x, y) of the target in the base coordinate system. T :

[0084]

[0085] Step 6: Use the transformation matrix from the base coordinate system to the geodetic coordinate system. Let X = (x, y) T Convert to geodetic coordinates to obtain high-precision geodetic coordinates of the target:

[0086]

[0087] Thus, the high-precision coordinates of the positioning target were calculated using the ultra-short baseline positioning method based on statistical difference. The beneficial effects of this invention are: with a reasonable layout of reference stations, the consistency of relative errors within the positioning plane is ensured, and the system's positioning accuracy is improved.

Claims

1. A method for ultra-short baseline positioning based on statistical difference, characterized in that... The specific process of the method is as follows: Step 1: Deploy differential reference stations on the seabed, calibrate the differential reference stations, and obtain their geodetic coordinates. Where l is the base station number and m is the number of base stations deployed; Step 2: Locate the target and obtain its slant range R. T Coarse direction finding results for locating the target (cosθ) T And the coarse localization result X of the target T ; Step 3: Obtain the horizontal position of each differential reference station in the matrix coordinate system. use The coarse localization result X of the target obtained in step two T Obtain the reference station I that provides the best differential positioning effect for the current positioning target; Step 4: Using the geodetic coordinates of base station I Obtain the true slope distance of base station I Direction angle And direct difference correction (Δx, Δy) T ; Step 5: Utilize the coarse positioning result X of the target obtained in Step 2. T Target slant range R T Coarse direction finding results for locating the target (cosθ) T The slant distance of base station I obtained in step four Direction angle And direct difference correction (Δx, Δy) T Obtain the relative differential correction coordinates X = (x, y) of the target in the base coordinate system. T ; Step 6: Use the transformation matrix from the base coordinate system to the geodetic coordinate system. Let X = (x, y) T Convert to geodetic coordinates to obtain the geodetic coordinates of the target.

2. The ultra-short baseline positioning method based on statistical difference according to claim 1, characterized in that: In step two, the target is located to obtain the slant range R of the target. T Coarse direction finding results for locating the target (cosθ) T And the coarse localization result X of the target T This includes the following steps: Step 21: Obtain the slant range from the array to the target. The azimuth angle from the array to the target Locate the target's coordinates in the matrix coordinate system n is the total number of measurements; Step 22: Take the average slant range from the array to the target measured multiple times as the target slant range. Steps 2 and 3: The average of the direction angles from the array to the target measured multiple times is taken as the coarse direction finding result for the target (cosθ). T =(cosθ) Tx cosθ Ty ) T : Step 24: Take the average coordinates of the target measured multiple times in the base coordinate system as the coarse positioning result of the target:

3. The ultra-short baseline positioning method based on statistical difference according to claim 2, characterized in that: In the coarse localization results Among them, R T The slant range for locating the target, where C is the speed of sound and d is the element spacing. It is the time delay difference in the x-direction of the array element in the matrix coordinate system during the i-th statistical analysis. It is the time delay difference in the y-direction of the array element in the array coordinate system during the i-th statistical analysis.

4. The ultra-short baseline positioning method based on statistical difference according to claim 3, characterized in that: In step three, the actual horizontal position of the differential reference station in the base coordinate system is obtained. use The coarse localization result X of the target obtained in step two T The optimal base station I for differential positioning of the current target is obtained as follows: Where I is the base station number for which differential positioning yields the best results. It is the actual horizontal position of the reference station in the matrix coordinate system.

5. The ultra-short baseline positioning method based on statistical difference according to claim 4, characterized in that: Step four involves using the geodetic coordinates of reference station I. Obtain the true slope distance of base station I Direction angle And direct difference correction (Δx, Δy) T This includes the following steps: Step 41: Obtain the X coordinates of the base array. jz =(x jz ,y jz ,z jz ) T Combined with the geodetic coordinates of base station I Obtain the true slope distance of base station I Step 4.2: Obtain the true coordinates of base station I in the matrix coordinate system. Based on the true slope distance of base station I and Obtain the horizontal direction angle of base station I Step 4.3: Perform n positioning operations on the reference station to obtain the coordinates of reference station I in the matrix coordinate system. Obtain the average coordinates of the base station I in the matrix coordinate system from n measurements. Step 44: Using the information obtained in Step 43 The true coordinates of base station I in the matrix coordinate system Obtain the direct difference correction (Δx, Δy) for base station I. T ; Where Δx is the direct differential correction in the Ix direction of the reference station, and Δy is the direct differential correction in the Iy direction of the reference station.

6. The ultra-short baseline positioning method based on statistical difference according to claim 5, characterized in that: The horizontal direction angle of base station I in step four-two Specifically as follows: in, It is the transformation matrix from the real geodetic coordinate system to the real matrix coordinate system.

7. The ultra-short baseline positioning method based on statistical difference according to claim 6, characterized in that: In step four-three, the average coordinates of the reference station I in the matrix coordinate system obtained from n measurements are discussed. As shown in the following formula:

8. The ultra-short baseline positioning method based on statistical difference according to claim 7, characterized in that: The direct differential correction (Δx, Δy) of reference station I in step four. T The details are as follows:

9. The ultra-short baseline positioning method based on statistical difference according to claim 8, characterized in that: In step five, the relative differential correction coordinates of the target in the base coordinate system are X = (x, y). T The details are as follows:

10. The ultra-short baseline positioning method based on statistical difference according to claim 9, characterized in that: The transformation matrix from the base coordinate system to the geodetic coordinate system in step six Let X = (x, y) T Convert to geodetic coordinates, as shown in the following formula:

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