CN107272004B - Single-beacon ranging and positioning method based on underwater beacon position correction - Google Patents

Abstract

The invention discloses a single beacon ranging and positioning method based on underwater beacon position correction, belonging to the technical field of underwater acoustic positioning. The invention utilizes the two-way propagation delay of underwater target acoustic ranging, and establishes a virtual receiving beacon according to the motion parameters in the geodetic coordinate system of the underwater target and the virtual transmitting beacon; The position and the two-way propagation delay measured by the single-beacon ranging system are used to establish an ellipsoid model, and the position of the actually deployed beacons is corrected; half of the two-way propagation delay is used as the one-way propagation delay reference value, combined with the correction After the underwater beacon position is established, the observation equation is established; the positioning equation group composed of the observation equation based on the correction of the underwater beacon position is solved, and the position of the underwater moving target in the geodetic coordinate system is obtained; The problem of inaccurate observation equations established by the beacon position improves the positioning accuracy of the single beacon ranging and positioning system for underwater moving targets.

Description

A single beacon ranging and positioning method based on underwater beacon position correction

technical field

The invention belongs to the technical field of underwater acoustic positioning, and in particular relates to a single beacon ranging and positioning method based on underwater beacon position correction.

Background technique

Acoustic ranging is a correlation measurement based on the correlation filtering effect of the correlation analysis method and the time-shift characteristics of the cross-correlation function of the signal and the signal after the delay. It is an effective method for accurate distance measurement in an environment with large background noise. Strong anti-interference ability, accurate measurement and high precision.

The acoustic ranging system is a common and effective method in the method of target positioning. When the acoustic ranging system works in the positioning system based on single beacon ranging, the rangefinder usually transmits the ranging in each ranging cycle. However, due to the influence of the underwater target movement, the single-beacon acoustic ranging system has the problem of non-common point in the acoustic ranging, and the conventional positioning solution model often takes half of the two-way propagation delay as the acoustic measurement of the observation equation. distance measurement.

With the development of ranging signal design and signal detection and estimation technology, the measurement accuracy of two-way propagation delay has been continuously improved. Half of the two-way propagation delay as the measurement equation of acoustic ranging is also accurate, but there is a The big problem is that this measurement is neither equal to the one-way delay between the position of the underwater target's transmitted signal and the beacon, nor is it equal to the one-way delay between the position of the underwater target's received signal and the beacon, so the two-way propagation delay is used. When half of the acoustic ranging is measured as the observation equation, the observation equation established by combining the position of the underwater target's transmitted signal or the position of the received signal and the position of the beacon is no longer accurate.

In order to solve the above problems, the present invention proposes a single beacon ranging and positioning method based on underwater beacon position correction.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method to solve the non-common point problem of the single-beacon acoustic ranging system for ranging transmission and reception, and use half of the two-way propagation delay as the observation equation. Or the single beacon ranging and positioning method based on the correction of underwater beacon position, which is the problem that the observation equation established by the position of the received signal and the position of the beacon is no longer accurate.

The object of the present invention is achieved in this way:

The invention discloses a single beacon ranging and positioning method based on underwater beacon position correction. The specific implementation steps include:

(1) Initialize the acoustic ranging system and calibrate the clock;

(2) Set the ranging period of the range finder of the acoustic ranging system as T, the forwarding delay of the acoustic measurement beacon as t _tat , and the range finder of the acoustic ranging system at the beginning of each ranging period T _k The ranging signal is transmitted at all times, and the underwater target records the time when the signal is transmitted by itself and the time when it receives the reply signal of the acoustic measurement beacon, and combines the recorded time information to obtain the two-way propagation delay signal of the underwater target acoustic ranging;

(3) Using the two-way propagation delay of underwater target acoustic ranging, and establishing virtual receiving beacons according to the motion parameters in the underwater target geodetic coordinate system and the actual beacons deployed underwater;

(4) Establish an ellipsoid model according to the actual deployed beacon position, the virtual receiving beacon position and the two-way propagation delay measured by the underwater target acoustic ranging system, and correct the position of the actual underwater beacons. ;

(5) Take half of the two-way propagation delay measured by the underwater target acoustic ranging system as the reference value of the one-way propagation delay for measurement, and establish an observation equation based on the corrected position of the underwater beacon;

(6) Solving the positioning equations composed of the observation equations based on the position correction of the underwater beacon, and obtaining the position of the underwater moving target in the geodetic coordinate system.

For a single beacon ranging and positioning method based on underwater beacon position correction, the specific implementation steps of the step (2) are as follows:

(2.1) Set the ranging period of the ranging instrument of the acoustic ranging system as T, the forwarding delay of the acoustic measuring beacon as t _tat , and the forwarding delay t _tat in each ranging period is equal in size;

(2.2) At the beginning of the k-th ranging period T _k , the rangefinder of the acoustic ranging system transmits a ranging signal, and the underwater target records the moment when the ranging signal is transmitted by itself as t _sendk , and the underwater target receives the ranging signal. The time of the acoustic determination beacon reply signal is t _receptk ;

(2.3) According to the time information recorded by the acoustic ranging system and the underwater target, the time elapsed by the underwater target from the transmitting point to the receiving point is obtained as t _receptk -t _sendk =t _sk +t _tat +t _rk , the acoustic ranging The two-way propagation delay measured by the system is t _sk +t _rk =t _receptk -t _sendk -t _tat , where t _sk +t _rk is the two-way propagation delay measured by the acoustic ranging system in the Kth cycle.

For a single beacon ranging and positioning method based on underwater beacon position correction, in the step (3), for the Kth ranging period, the motion parameters in the geodetic coordinate system of the underwater target are transferred to the actual distribution On the deployed single beacon X _t , construct a virtual beacon X _vtk , and obtain the relative positional relationship between the virtual beacon X _vtk and the actual deployed single beacon X _t as follows:

为载体坐标系{B}变换到大地坐标系{L}的旋转矩阵，c为声速，Δt为目标运动参数测量的采样间隔。Among them, ^L v _b is the speed of the underwater target in the geodetic coordinate system, ^B v _b is the speed of the underwater target in the carrier coordinate system,

is the rotation matrix of the carrier coordinate system {B} transformed to the geodetic coordinate system {L}, c is the speed of sound, and Δt is the sampling interval of the target motion parameter measurement.

For a single beacon ranging and positioning method based on underwater beacon position correction, the actual beacon position, the virtual receiving beacon position and the underwater target acoustic ranging system measured in the step (4) The two-way propagation delay of the single-beacon acoustic ranging positioning system transforms the problem of the non-co-point transmission and reception of the two-way propagation delay of the single-beacon acoustic ranging positioning system into the problem of the sum of the one-way propagation delays from the transmitting point to different beacons. The specific implementation method is as follows:

||X _sk -X _t ||+||X _rk -X _t ||=||X _sk -X _t ||+||X _sk -X _vtk ||

Among them, the corresponding one-way propagation delay between the transmitting point X _sk and the actually deployed beacon position X _t is t _sk ; the corresponding one-way propagation delay between the transmitting point X _sk and the virtual receiving beacon position X _vtk is t _rk ; X _rk is the position coordinate of the receiving point;

The underwater target acoustic ranging signal transmission point X _sk , the actual underwater beacon X _t and the established virtual receiving beacon X _vtk constitute an ellipsoid model, in which the virtual receiving beacon X _vtk and the actual deployment beacon X _t is the two foci of the ellipsoid, and the underwater target acoustic ranging emission point X _sk is a point on the ellipse.

For a single beacon ranging and positioning method based on underwater beacon position correction, the position of the underwater beacon is corrected through steps (1) to (4), and the corrected underwater beacon is transmitted to the underwater target The one-way propagation delay corresponding to the point is half of the two-way propagation delay.

For a single beacon ranging and positioning method based on the correction of the underwater beacon position, in the step (5), the one-way propagation delay corresponding to the corrected underwater beacon to the underwater target launch point is used as the reference value Measurements are made, and an observation equation is established based on the corrected underwater beacon position and half of the two-way propagation delay measured by the single-beacon ranging system.

For a single beacon ranging and positioning method based on underwater beacon position correction, in the step (6), each observation equation based on underwater beacon position correction in the positioning equation group is linearized to eliminate the need to be The quadratic term of the underwater target position is obtained, the linearized positioning equations are solved, and the position of the underwater target in the geodetic coordinate system is obtained through the least squares method.

The beneficial effects of the present invention are:

A single beacon ranging and positioning method based on underwater beacon position correction disclosed in the present invention can utilize the two-way propagation delay of underwater target acoustic ranging, according to the motion parameters in the underwater target geodetic coordinate system and the virtual transmission signal establish a virtual receiving beacon; establish an ellipsoid model according to the actual deployed beacon position, the virtual receiving beacon position and the two-way propagation delay measured by the single beacon ranging system. Carry out position correction; take half of the two-way propagation delay as the measurement of the one-way propagation delay, and establish an observation equation combined with the corrected position of the underwater beacon; the positioning equation composed of the observation equation based on the correction of the underwater beacon position group solution, the position of the underwater moving target in the geodetic coordinate system is obtained; the problem of non-common point in the distance measurement of the single beacon acoustic ranging system is solved, and the half of the two-way propagation delay is used as the observation equation. When measuring the acoustic ranging of the single beacon, the observation equation established by combining the position of the transmitted signal or the received signal of the underwater target and the position of the beacon is no longer accurate, which improves the positioning accuracy of the single beacon ranging and positioning system for the underwater moving target.

Description of drawings

1 is a schematic diagram of the construction principle of a virtual receiving beacon according to the present invention;

2 is a schematic diagram of a single beacon ranging and positioning ellipse model constructed by the present invention;

3 is a schematic diagram of the underwater target navigation trajectory of the present invention;

FIG. 4 is a comparison of the positioning error between the method disclosed in the present invention and the conventional observation method.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings.

Referring to Figure 1, the working principle of the acoustic ranging system is: when the positioning system based on single beacon ranging works, the rangefinder of the acoustic ranging system transmits a ranging signal at the beginning of each ranging cycle, and the ranging period is T. The position of the beacon is X _t =(x _t , y _t , z _t ) ^T , and the forwarding delay t _tat of the acoustic beacon is preset and known, and the size of each ranging period is equal. When the underwater target propagates back and forth between the target and the beacon, the position where the rangefinder transmits and receives the signal changes due to the movement of the underwater target.

The time when the underwater target transmits the ranging signal is t _send , which is known for the underwater target. The time when the underwater target receives the beacon reply signal is t _recept , and the receiving time is also known for the underwater target. The time elapsed from the transmitting point X _s1 to the receiving point X _r1 in the first ranging cycle is t _recept1 -t _send1 =t _s1 +t _tat +t _r1 , then the two-way propagation delay measured by the acoustic ranging system is t _recept1 -t _send1 -t _tat ; the time elapsed from the transmitting point X _s2 to the receiving point X _r2 in the second ranging cycle is t _recept2 -t _send2 =t _s2 +t _tat +t _r2 , then the acoustic ranging system The measured round-trip propagation delay is t _recept2 -t _send2 -t _tat .

For the first ranging period, transfer the motion parameters of the target to the actual deployed single beacon X _t , and construct a virtual beacon X _vt1 , so that the virtual beacon X _vt1 and the actual deployed single beacon X The relative position relationship of _t satisfies:

为载体坐标系{B}变换到大地坐标系{L}的旋转矩阵，c为声速。Δt为目标运动参数测量的采样间隔。同理，得到第2个测距周期对应的虚拟信标X_vt2。Among them, ^L v _b is the speed of the underwater target in the geodetic coordinate system, ^B v _b is the speed of the underwater target in the carrier coordinate system,

is the rotation matrix for transforming the carrier coordinate system {B} to the geodetic coordinate system {L}, and c is the speed of sound. Δt is the sampling interval of the target motion parameter measurement. Similarly, the virtual beacon X _vt2 corresponding to the second ranging period is obtained.

2 , the corresponding one-way propagation delay between the transmission point X _s1 and the virtual beacon X _vt1 is t _r1 , and the corresponding one-way propagation delay between the transmission point X _s1 and the real beacon X _t is t _s1 . Then for the first ranging period, the following relationship is satisfied:

||X _s1 -X _t ||+||X _r1 -X _t ||=||X _s1 -X _t ||+||X _s1 -X _vt1 || (2)

At this time, the problem of non-co-located transmission and reception of two-way propagation delay is transformed into the problem of the sum of one-way propagation delays from the transmitting point to different beacons. The emission point X _s1 , the real beacon X _t and the virtual beacon X _vt1 constitute an ellipse model, X _vt1 and X _t are the two foci of the ellipse, and X _s1 is a point on the ellipse.

According to the properties of the ellipse, the emission point X _s1 , the real beacon X _t and the virtual beacon X _vt1 satisfy the following relation:

The eccentricity e of an ellipse is defined as the ratio of the focal length to the major axis of the ellipse, and the value range is 0<e<1. The greater the eccentricity, the flatter the ellipse; the smaller the eccentricity, the closer the ellipse is to a circle. The eccentricity e satisfies the following relation:

Wherein, the time elapsed by the target from the transmitting point to the receiving point is t _recept1 -t _send1 =t _s1 +t _tat +t _r1 , and the target generally moves at a low speed, so e is a small amount.

The distance from the target emission point X _s1 to the ellipse center X _o1 is ||X _s1 -X _o1 ||, and the following relationship is obtained according to the ellipse equation:

Because e ² <<1, the observation equation from the underwater target launch point X _s1 to the ellipse center X _o1 is:

In the same way, the observation equation from the target emission point X _s2 to the ellipse center X _o2 is:

In addition, a single beacon ranging and positioning method based on underwater beacon position correction disclosed in the present invention has also been simulated and analyzed, and the analysis results are as follows:

Combined with Figure 3, it is the comb-shaped navigation trajectory of the underwater target. The position of the acoustic beacon deployed on the seabed is (0, 0, 4000) m, and the forwarding delay of the beacon is 20 ms; the underwater target is at a constant depth of 4100 m before the It moves in a straight line at a uniform speed of 1m/s; the initial position of the underwater target is (-1000,-300)m, and the ranging period is 20s. Add the eastward speed error with standard deviation of 0.005m/s and the northward speed error of 0.005m/s to the speed under the underwater target geodetic coordinates. Combined with Fig. 4, the positioning error between the method of the present invention and the conventional method is compared.

The positioning method based on the calibration position of the underwater beacon, takes half of the two-way propagation delay as the measurement of the one-way propagation delay, and establishes the observation equation by combining the position of the underwater target transmitted signal and the calibration position of the underwater beacon, and the average positioning error is 1.607 m, the standard deviation is 1.853m, and the positioning error at the corner of the underwater target navigation track increases significantly; the positioning method based on the position correction of the underwater beacon provided by the present invention takes half of the two-way propagation delay as the one-way propagation delay. Quantitative measurement, combined with the position of the underwater target's transmitted signal and the corrected position of the underwater beacon, an observation equation was established. The mean value of the positioning error was 0.305m, and the standard deviation was 0.303m. The positioning error was significantly smaller than the positioning error caused by the time delay approximation. Among them, the underwater target's navigation trajectory The positioning error at the corner is more obviously improved.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. a single beacon ranging and positioning method based on underwater beacon position correction, is characterized in that, concrete realization step comprises: (1) Initialize the acoustic ranging system and calibrate the clock; (2) Set the ranging period of the range finder of the acoustic ranging system as T, the forwarding delay of the acoustic measurement beacon as t _tat , and the range finder of the acoustic ranging system at the beginning of each ranging period T _k The ranging signal is transmitted at all times, and the underwater target records the time when the signal is transmitted by itself and the time when it receives the reply signal of the acoustic measurement beacon, and combines the recorded time information to obtain the two-way propagation delay signal of the underwater target acoustic ranging; (3) Using the two-way propagation delay of underwater target acoustic ranging, and establishing virtual receiving beacons according to the motion parameters in the underwater target geodetic coordinate system and the actual beacons deployed underwater; (4) Establish an ellipsoid model according to the actual deployed beacon position, the virtual receiving beacon position and the two-way propagation delay measured by the underwater target acoustic ranging system, and correct the position of the actual underwater beacons. ; (5) Take half of the two-way propagation delay measured by the underwater target acoustic ranging system as the reference value of the one-way propagation delay for measurement, and establish an observation equation based on the corrected position of the underwater beacon; (6) Solving the positioning equations composed of the observation equations based on the position correction of the underwater beacon, and obtaining the position of the underwater moving target in the geodetic coordinate system. 2. a kind of single beacon ranging and positioning method based on underwater beacon position correction according to claim 1, is characterized in that, the concrete realization step of described step (2) is as follows: (2.1) Set the ranging period of the ranging instrument of the acoustic ranging system as T, the forwarding delay of the acoustic measuring beacon as t _tat , and the forwarding delay t _tat in each ranging period is equal in size; (2.2) At the beginning of the k-th ranging period T _k , the rangefinder of the acoustic ranging system transmits a ranging signal, and the underwater target records the moment when the ranging signal is transmitted by itself as t _sendk , and the underwater target receives the ranging signal. The time of the acoustic determination beacon reply signal is t _receptk ; (2.3) According to the time information recorded by the acoustic ranging system and the underwater target, the time elapsed by the underwater target from the transmitting point to the receiving point is obtained as t _receptk -t _sendk =t _sk +t _tat +t _rk , the acoustic ranging The two-way propagation delay measured by the system is t _sk +t _rk =t _receptk -t _sendk -t _tat , where t _sk +t _rk is the two-way propagation delay measured by the acoustic ranging system in the Kth cycle. 3. a kind of single beacon ranging and positioning method based on underwater beacon position correction according to claim 2, is characterized in that: in the described step (3), for the Kth ranging cycle, the underwater The motion parameters in the target geodetic coordinate system are transferred to the actual deployed single beacon X _t to construct a virtual beacon X _vtk to obtain the relative positional relationship between the virtual beacon X _vtk and the actual deployed single beacon X _t for:

Among them, ^L v _b is the speed of the underwater target in the geodetic coordinate system, ^B v _b is the speed of the underwater target in the carrier coordinate system,

is the rotation matrix of the carrier coordinate system {B} transformed to the geodetic coordinate system {L}, c is the speed of sound, and Δt is the sampling interval of the target motion parameter measurement. 4. a kind of single beacon ranging and positioning method based on underwater beacon position correction according to claim 1, is characterized in that: the beacon position actually deployed in the described step (4), the virtual receiving signal The two-way propagation delay measured by the beacon position and the underwater target acoustic ranging system transforms the problem of non-co-point transmission and reception of the two-way propagation delay of the single-beacon acoustic ranging and positioning system into the one-way propagation from the transmitting point to different beacons. The problem of extension and reconciliation, the specific implementation method is as follows: ||X _sk -X _t ||+||X _rk -X _t ||=||X _sk -X _t ||+||X _sk -X _vtk || Among them, the corresponding one-way propagation delay between the transmitting point X _sk and the actually deployed beacon position X _t is t _sk ; the corresponding one-way propagation delay between the transmitting point X _sk and the virtual receiving beacon position X _vtk is t _rk ; X _rk is the position coordinate of the receiving point; The underwater target acoustic ranging signal transmission point X _sk , the actual underwater beacon X _t and the established virtual receiving beacon X _vtk constitute an ellipsoid model, in which the virtual receiving beacon X _vtk and the actual deployment beacon X _t is the two foci of the ellipsoid, and the underwater target acoustic ranging emission point X _sk is a point on the ellipse. 5. a kind of single beacon ranging and positioning method based on underwater beacon position correction according to claim 1, is characterized in that: by step (1) to step (4), the position of underwater beacon is corrected, The one-way propagation delay corresponding to the corrected underwater beacon to the underwater target launch point is half of the two-way propagation delay. 6. a kind of single beacon ranging and positioning method based on underwater beacon position correction according to claim 1, is characterized in that: in described step (5), use the underwater beacon after correction to underwater The one-way propagation delay corresponding to the target launch point is measured as a reference quantity, and an observation equation is established based on the corrected underwater beacon position and half of the two-way propagation delay measured by the single-beacon ranging system. 7. a kind of single beacon ranging and positioning method based on underwater beacon position correction according to claim 1, is characterized in that: in described step (6), each of positioning equation group is based on underwater beacon The position-corrected observation equation is linearized, the quadratic term of the position of the underwater target to be found is eliminated, the linearized positioning equations are solved, and the position of the underwater target in the geodetic coordinate system is obtained by the least squares method. .

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