KR101755307B1 - A position measurement error correcting method of underwater moving objects - Google Patents

Abstract

A method for correcting a position measurement error of an underwater vehicle according to the present invention includes a USBL transceiver for receiving an acoustic pulse signal and measuring a USBL signal, a bus line having a GPS, a USBL responder for generating the acoustic pulse signal, and an extended Kalman filter 1. An underwater navigation system for tracking a position of an underwater vehicle, comprising: (a) reading the latitude and longitude of the underwater vehicle from the extended Kalman filter; and cutting the measured X- and Y- Setting an error; (b) resetting the number of signal reception defects and waiting for the measured USBL signal; (c) calculating a signal range and a signal reception delay time by receiving the measured USBL signal, and calculating a delay count; (d) reading the speed data of the underwater vehicle from the navigation data memory, and calculating a position of movement of the underwater vehicle during the calculated delay time; (e) correcting a measured value of the USBL signal at a predetermined time; (f) calculating a measurement error of the corrected USBL signal and determining whether the signal reception failure has occurred; (g) increasing a count of the number of defective signal reception by one when a signal reception failure occurs, and discarding the error of the measured USBL signal; And (h) performing an extended Kalman filtering operation to cause the corrected USBL signal to have a normal distribution when signal reception failure does not occur.

Description

Technical Field [0001] The present invention relates to a position measurement error correcting method for an underwater moving object,

The present invention relates to a position measurement error correction method, and more particularly, to a position measurement error correction method in which a random noise is added to a position measurement signal of an ultrasonic position measuring device of a moving object, The present invention relates to a position measurement error correction method for an underwater mobile object that can improve the accuracy of an underwater navigation system in which a position signal of an ultrasonic position measurement device is integrated by providing a Gaussian normal distribution even in a microscopic region.

In general, underwater vehicles include Remotely Operated Vehicles (ROV) and Autonomous Underwater Vehicle (AUV), and there are manned submersibles for scientific exploration and underwater observation.

Acoustic positioning systems such as USBL (Ultra-Short Base Line), LBL (Long Base Line), and SBL (Short Base Line) are generally used for tracking the position of these devices.

Among them, LBL is capable of precise position measurement, but it is troublesome to install a large number of transducers on the sea floor, and there is a limitation that position measurement can be performed only in the area where a transducer is installed.

SBL is measured by installing three or more transducers on the ship, so there is no limitation on the operating area, but there is a disadvantage that the measurement error becomes large as the distance of the moving object in the water becomes distant.

USBL is a method to measure the azimuth and distance of receiving signal by installing four transceivers on one sensor and measure the three-dimensional position in water. It is more simple than SBL and LBL, Although there is no limit to the sea area and it is easy to install, there is a disadvantage that the error is increased due to sensitivity to external noise, outliers, ie, signal reception defects frequently occur, and angular resolution is constant, .

Since the ultrasonic position tracking apparatus measures the propagation delay time of the underwater acoustic signal and converts the distance, the position measurement time increases in proportion to the distance of the moving object.

In the case of underwater object position measurement in the range of hundreds of meters, it is possible to sample 1 second, but as the distance increases, the sampling interval becomes longer and the position measurement of 6000 m distance object acquires the position signal in 8 ~ 20 second time interval depending on the system.

The navigation system based on the inertial sensor has the advantage of estimating the position and attitude using only the built-in inertial sensor, but an auxiliary signal is necessarily required because the error accumulates with time.

In the underwater navigation system, various integrated navigation techniques such as a method of fusing a position measurement signal of a speed or an ultrasonic position locating apparatus based on an inertial sensor, a method of using a terrain contrast or a mathematical model as auxiliary information are being developed.

Various nonlinear filtering techniques such as Kalman filter, extended Kalman filter, sigma-point Kalman filter, and particle filter have been developed and utilized for position estimation of integrated navigation system.

The measurement accuracy of USBL position is increased as the distance of the underwater mobile body increases, and the accuracy of the USBL currently operating has an error of 3% ~ 0.1% rms of the distance (slant range).

Therefore, an object with a distance of 6,000 m has an rms measurement error of at least 18 m with 0.3% error.

The USBL system provides the position signal by converting the obtained position signal into the absolute position of the moving object in conjunction with the GPS signal of the aquarium.

Absolute position obtained from USBL provides digital position data with truncated significant digits within a meaningful range for digital positioning of the underwater vehicle.

For example, a commercial USBL with 0.3% accuracy in the 6,000 m range has a truncated error of about 2 m in the north direction and about 1.5 m in the east direction at the latitude 36 °.

Due to this truncation error, the USBL output signal has a noise characteristic with a normal distribution error from a macroscopic point of view, but has a deterministic signal characteristic from a microscopic point of view.

In addition to the USBL, the GPS output signal also has a cutoff error, so it exhibits the same deterministic signal characteristics as the USBL in the microscopic range.

Therefore, when integrating the inertial system and the USBL signal in order to improve the accuracy of the navigation system, it is difficult to model the error signal of the USBL position measurement with a Gaussian random noise having a normal distribution.

Therefore, when the USBL output signal is used as it is, the precondition that the position measurement error has a normal distribution can not be satisfied in the microscopic region. Therefore, there is a limitation in implementing the precision navigation system by applying the Kalman filter or the extended Kalman filter.

Since USBL calculates the distance (distance = sound velocity x propagation delay time) of the moving object by measuring the propagation delay time between the transmission and reception of the acoustic signal, Position measurement error exists.

For example, when the position of a remote controlled unmanned submersible traveling at a distance of 6,000 m is measured by the responder mode (unidirectional distance measuring method), the sound transmission speed in the water is about 1,500 m / s. The time delay to be transmitted is about 4 seconds.

On the other hand, in the USBL position measurement, the transponder mode is a bidirectional distance measurement method in which an acoustic signal is transmitted from a line feeder and a response signal is received after receiving the signal, and a response signal is received from a line- , Autonomous unmanned submersible or manned submersible), there is an acoustic signal transmission delay time of about 8 seconds.

During the propagation delay time, there is a change in the position of the underwater vehicle, so compensation for the position error due to the time delay is necessary for accurate position measurement.

In addition, if the signal / noise ratio of the received signal is low depending on the underwater environment and the operation conditions of the ship, the acoustic signal received in the water can not be measured because the outlier occurs, The signal measurement period tends to increase in multiples.

Therefore, in order to accurately measure the position of a moving object in the underwater, it is necessary to perform position correction considering the transmission delay of the USBL and the outlier signal characteristic.

US 8767511 B2

An object of the present invention is to add a random noise to a measurement signal within a cutoff error range when a position measurement signal obtained by an ultrasonic position measuring apparatus of a moving object is deterministically given by a cutoff error and calculate a time delay according to an operation mode It is possible to compensate the position change due to the movement of the moving object in the underwater and the delay of the sound signal transmission time, to correct the positioner error by correcting the outlier of the position signal and correcting the position error, Which can make the Gaussian normal distribution even in the in-plane region.

According to another aspect of the present invention, there is provided a method for correcting a position measurement error of a moving object in a moving object, the method comprising the steps of: receiving a sound pulse signal and measuring a USBL signal; A method for correcting a position measurement error of an underwater navigation system in an underwater navigation system, the method comprising: (a) reading the latitude and longitude of the underwater vehicle from the extended Kalman filter; Setting a cut-off error in the X-direction and the Y-direction of the measured USBL signal; (b) resetting the number of signal reception defects and waiting for the measured USBL signal; (c) calculating a signal range and a signal reception delay time by receiving the measured USBL signal, and calculating a delay count; (d) reading the speed data of the underwater vehicle from the navigation data memory, and calculating a position of movement of the underwater vehicle during the calculated delay time; (e) correcting a measured value of the USBL signal at a predetermined time; (f) calculating a measurement error of the corrected USBL signal and determining whether the signal reception failure has occurred; (g) increasing a count of the number of defective signal reception by one when a signal reception failure occurs, and discarding the error of the measured USBL signal; And (h) performing an extended Kalman filtering operation to cause the corrected USBL signal to have a normal distribution when signal reception failure does not occur.

According to another aspect of the present invention, there is provided a method for correcting a position measurement error of a moving object in an underwater vehicle, the method comprising the steps of: receiving the USBL responder, a first inertial sensor, a first velocity sensor, Remote controlled unmanned submersible; And an autonomous unmanned submersible vehicle having a USBL transponder, a second inertial sensor, a second speed sensor, a second bow angle-posture sensor, and a second depth sensor.

(상기 X_USBL(t_k) 및 상기 Y_USBL(t_k)는 각각 시간(t_k)에서 USBL을 통해 측정된 x 축상 위치 및 y 축상 위치이고, 상기 ΔX_GPS 및 상기 ΔY_GPS 는 GPS를 통해 측정된 상기 모선의 위치 변화량이며, 상기 V_E(t_k-i) 및 상기 V_N(t_k-i)는 각각 시간(t_k-i)에서의 동쪽 및 북쪽 방향으로의 상기 원격 조종 무인 잠수정의 속도)를 포함하는 것을 특징으로 한다.In order to attain the above object, in the step (e) of the method for correcting the position measurement error of the present invention, when the underwater vehicle is a remote controlled unmanned submersible vehicle operating as a USBL responder, (e-1) The USBL signal processing time interval (T _USBL ), the sound wave transmission average acoustic velocity (V _a ), the sampling time interval (? T) of the first inertia sensor, and the 100 Hz count number (j = T _USBL / t); (e-2) receiving an acoustic pulse in the USBL transceiver when the acoustic pulse is generated in the USBL responder, the predetermined distance (R ₁ ) away from the bus line; (e-3) calculating the position of the remote controlled unmanned submersible and the distance (R ₁ ) to calculate a 100 Hz count number (j ₁ = R ₁ / V _a δt); (e-4) measuring a position change amount (DELTA X _GPS , DELTA Y _GPS ) of the bus line to correct a change in position of the bus line; And (e-5) calculating the position of the remote controlled unmanned submersible according to the following equation:

(Above and X _USBL (t _k) and the Y _USBL (t _k) are each time (t _k) The measured x through the USBL in axial position and the y-axis position, the ΔX _GPS and the ΔY _GPS is measured by the GPS with a position change of the bus bars, by including the V _E (t _ki) and the V _N (t _ki) is the remote control the speed of the unmanned submersible to the east and the north direction at each time (t _ki)) .

(상기 X_USBL(t_k) 및 상기 Y_USBL(t_k)는 각각 시간(t_k)에서 USBL을 통해 측정된 x 축상 위치 및 y 축상 위치이고, 상기 ΔX_GPS 및 상기 ΔY_GPS 는 GPS를 통해 측정된 상기 모선의 위치 변화량이며, 상기 V_E(t_k-i) 및 상기 V_N(t_k-i)는 각각 시간(t_k-i)에서의 동쪽 및 북쪽 방향으로의 상기 원격 조종 무인 잠수정의 속도)를 포함하는 것을 특징으로 한다.In order to attain the above object, in the step (e) of the method for correcting a position measurement error of the present invention, when the underwater vehicle is a remote controlled unmanned submersible vehicle operated as a USBL transponder, (e-1) The USBL signal processing time interval (T _USBL ), the sound wave transmission average acoustic velocity (V _a ), the sampling time interval (? T) of the first inertia sensor, and the 100 Hz count number (j = T _USBL / t); (e-2) receiving an acoustic pulse from the USBL transceiver having a predetermined distance (R ₁ ) from the bus line when the acoustic pulse is generated in the USBL responder, and outputting a response signal; (e-3) receiving the response signal by the USBL transceiver in which the bus is moved and the remote control unmanned submersible has a distance R ₂ from the bus line; (e-4) The reciprocating distance (R ₁ + R ₂ ) / 2 is calculated using the distance R ₁ and the distance R ₂ , and the position of the remote controlled UAV is measured. (j ₁ = R ₁ / V _a隆 t); (e-5) measuring a position change amount (DELTA X _GPS , DELTA Y _GPS ) of the bus line to correct a change in position of the bus line; And (e-6) calculating the position of the remote controlled unmanned submersible according to the following equation:

(Above and X _USBL (t _k) and the Y _USBL (t _k) are each time (t _k) The measured x through the USBL in axial position and the y-axis position, the ΔX _GPS and the ΔY _GPS is measured by the GPS with a position change of the bus bars, by including the V _E (t _ki) and the V _N (t _ki) is the remote control the speed of the unmanned submersible to the east and the north direction at each time (t _ki)) .

(상기 X_USBL(t_k) 및 상기 Y_USBL(t_k)는 각각 시간(t_k)에서 USBL을 통해 측정된 x 축상 위치 및 y 축상 위치이고, 상기 ΔX_GPS 및 상기 ΔY_GPS 는 GPS를 통해 측정된 상기 모선의 위치 변화량이며, 상기 V_E(t_k-i) 및 상기 V_N(t_k-i)는 각각 시간(t_k-i)에서의 동쪽 및 북쪽 방향으로의 상기 자율 무인 잠수정의 속도)를 포함하는 것을 특징으로 한다.In order to attain the above object, in the eighth step of the method for correcting a position measurement error of an underwater vehicle according to the present invention, when the underwater vehicle is an autonomous unmanned submersible operated by a USBL transponder, the speed of sound USBL signal processing time interval (T _USBL), a sound wave transmission average (V _a), the signal processing for the sampling time interval (δt), asynchronous transfer mode, data received in the second inertial sensor time (Δt _a) and asynchronous step of setting an initial value for the USBL signal received takes 100 Hz counting the number of times (δt j _a = _a / δt) in transmission mode; (e-2) receiving an acoustic pulse from the USBL transceiver having a predetermined distance (R ₁ ) away from the bus line when the acoustic pulse is generated in the USBL responder, and outputting a response signal; (e-3) receiving the response signal by the USBL transceiver in which the bus line is moved and the autonomous unattended submersible is separated from the bus line by a distance R ₂ ; (e-4) calculating a reciprocating distance (R ₁ + R ₂ ) / 2 using the distance R ₁ and the distance R ₂ and measuring the position of the autonomous unmanned submersible; (e-5) If the bus transmits the measured position data of the autonomous unmanned submersible to the autonomous unmanned submersible in the asynchronous transfer mode, the measured position data of the autonomous unmanned submersible at the predetermined time To calculate a 100 Hz count number (j ₁ = R ₁ / V _a隆 t); (e-6) measuring a position change amount (DELTA X _GPS , DELTA Y _GPS ) of the bus line to correct a positional change of the bus line; And (e-7) calculating the position of the autonomous unmanned submersible according to the following equation:

(Above and X _USBL (t _k) and the Y _USBL (t _k) are each time (t _k) The measured x through the USBL in axial position and the y-axis position, the ΔX _GPS and the ΔY _GPS is measured by the GPS Wherein the V _E (t _ki ) and the V _N (t _ki ) each include the speed of the autonomous unmanned submersible in the east and north directions at time _tki ) .

In order to achieve the above object, the method for correcting a position measurement error of the present invention may further include propagating an error covariance matrix after step (g) and returning to step (b).

(상기 R_k는 시간(t_k)에서의 계측 오차 공분산이고, 상기 R은 계측 오차 공분산이며, 상기 α는 신호 수신 불량 개수)를 포함하는 것을 특징으로 한다.In order to achieve the above object, the present invention provides a method for correcting errors in position measurement of a moving object in a moving object, the method comprising the steps of discarding an error of the measured USBL signal, wherein n * σ (n = 3 to 5, Removing the measured USBL signal exceeding a predetermined threshold value; Counting the number of signal reception defects; And correcting a measurement error covariance characteristic of the USBL signal due to the signal reception failure using the following equation:

It characterized in that it comprises a (a measurement error covariance R _k at the time (t _k), wherein R is the measurement error covariance, wherein α is the number of bad reception signal).

In order to achieve the above object, the step (h) of the method for correcting a position measurement error of a moving object of the present invention comprises the steps of: (h-1) determining a distance from the USBL transceiver to the underwater vehicle, And receiving and initializing the absolute position of the mobile station; (h-2) detecting the inertial force of the motion of the first and second inertial sensors to the underwater vehicle to provide an acceleration and an angular velocity; (h-3) calculating the estimated distance of the underwater vehicle by driving the strap-down inertial navigation algorithm with the acceleration and the angular velocity being applied by the extended Kalman filter; (h-4) propagating the error covariance matrix by receiving the estimated distance; (h-5) calculating a Kalman gain for the first and second velocity sensors and a Kalman gain for the USBL, and updating the error covariance matrix.

In order to achieve the above object, the data required for calculating the Kalman gain for the first and second velocity sensors in the step (h-5) of the method for correcting the position measurement error of the moving object according to the present invention, The asynchronous multirate velocity data and the depth data calculated by the strap-down inertial navigation algorithm on the velocity data of each of the underwater vehicles measured by the two-speed sensor, the depth data of each of the underwater vehicles measured by the first and second depth sensors, Data is a sum of data.

In order to achieve the above object, the present invention provides a method of correcting a position measurement error of a moving object, comprising: (h-5) a step (h-6) of receiving a sum of the velocity data and depth data, Updating the data; And (h-7) calculating a Kalman gain for the first and second velocity sensors and a Kalman gain for the first and second depth sensors.

In order to achieve the above object, the data required for calculating the Kalman gain for the USBL in the step (h-5) of the method for correcting the position measurement error of the underwater vehicle may include: And the position data is the sum of the position data calculated through the strap-down inertia navigation algorithm.

In order to achieve the above object, the present invention provides a method for correcting a position measurement error of a moving object, the method comprising: correcting a time delay error by receiving a sum of the position data after the step (h-7) ; Adding random noise to the position on the x-axis and the position on the y-axis when the signal reception failure does not occur, and adjusting the measurement error covariance; Increasing the number of defective signal reception by one when the signal reception failure occurs and discarding the error of the measured USBL signal and propagating the error covariance matrix; And updating the state estimation data for the first and second velocity sensors using the adjusted measurement error covariance and calculating a Kalman gain for the USBL (S50); Returning to step S100 driving the strap-down inertia navigation algorithm by correcting errors of the state estimation update data for the first and second velocity sensors; The strap-down inertial navigation algorithm receives the propagated error covariance matrix and the state estimation update data for the first and second speed sensors with the error corrected, and corrects the position, velocity, and attitude data of the underwater vehicle Further comprising the steps of:

According to another aspect of the present invention, there is provided a method for correcting a position measurement error of a moving object in a moving object, the method comprising the steps of: receiving a sound pulse signal and measuring a USBL signal; A method for correcting a position measurement error of an underwater navigation system in an underwater navigation system, the method comprising: (a) reading the latitude and longitude of the underwater vehicle from the extended Kalman filter; Setting a cut-off error in the X-direction and the Y-direction of the measured USBL signal; (b) resetting the number of signal reception defects and waiting for the measured USBL signal; (c) calculating a signal range and a signal reception delay time by receiving the measured USBL signal, and calculating a delay count; (d) reading the speed data of the underwater vehicle from the navigation data memory, and calculating a position of movement of the underwater vehicle during the calculated delay time; (e) correcting a measured value of the USBL signal at a predetermined time; (f) calculating a measurement error of the corrected USBL signal and determining whether the signal reception failure has occurred; (g) increasing a count of the number of defective signal reception by one when a signal reception failure occurs, and discarding the error of the measured USBL signal; And (h) performing an extended Kalman filtering operation to cause the corrected USBL signal to have a normal distribution when a signal reception failure does not occur, wherein the extended Kalman filter is configured to perform the movement of the bus and the underwater vehicle And the measured value of the USBL signal is corrected by a indirect feedback method for updating the data in consideration of the USBL signal.

Specific details of other embodiments are included in the " Detailed Description of the Invention "and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and / or features of the present invention and the manner of achieving them will be apparent by reference to various embodiments described in detail below with reference to the accompanying drawings.

However, the present invention is not limited to the configurations of the embodiments described below, but may be embodied in various other forms, and each embodiment disclosed in this specification is intended to be illustrative only, It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

According to the present invention, when the position measurement value and the position estimation value of the moving object exceed the threshold value of the error normal value, it is determined that the signal reception is defective and the measurement error covariance is excluded from the update of the measurement signal. It is possible to overcome the limitation of the USBL in which a signal reception failure occurs intermittently or continuously.

In addition, when the inertial system and the USBL signal are integrated, the error signal of the USBL position measurement is modeled as a random noise having a normal distribution, so that the error of the navigation system incorporating the GPS position signal is reduced and the accuracy of the underwater navigation system is improved do.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an integrated underwater navigation system for implementing a position error correction method for an underwater vehicle according to the present invention; FIG.
FIG. 2 is a graph showing an XY plane view of a signal including a USBL signal and random noise measured in the integrated navigation navigation system shown in FIG. 1. FIG.
Fig. 3 is a graph showing a position error (a) measured in the integrated navigation navigation system shown in Fig. 1 and a signal (b) including random noise in a histogram.
4 is a flowchart showing the operation of the method for correcting the characteristics of the USBL signal measured in the integrated navigation navigation system shown in FIG.
FIGS. 5A to 5C are views showing the flow of a USBL signal measured according to a time delay in the integrated navigation navigation system shown in FIG. 1. FIG.
FIG. 6 is a view showing a position of a moving object underwater compensated for time delay in the integrated navigation navigation system shown in FIG. 1. FIG.
FIG. 7 is an operation flowchart for explaining an extended Kalman filtering operation of the USBL signal characteristic correction method shown in FIG. 4 in detail.
FIG. 8 is a graph simulating the position (a) on the x-axis and the position (b) on the y-axis of the autonomous unmanned submersible as measured in USBL over time according to an embodiment of the present invention.
9 is a graph showing a position error (a) on the x-axis and a position error (b) on the y-axis, which are measured in the USBL, in the histogram according to an embodiment of the present invention.
FIG. 10 is a graph showing the position (a) on the x-axis where a random error is added to the USBL position measurement value on the x-axis of the autonomous unmanned submersible shown in FIG. 8 and the y-axis position (b) where random error is added to the y- It is a graph that is compared with the passage of time.
11 is a graph showing a position error (a) on the x-axis and a position error (b) on the y-axis, to which a random error is added, as shown in FIG.
12 is a graph showing the x-axis position error (a) and the y-axis position error (b) modeled by the Gaussian distribution function of the random error shown in Fig.
FIG. 13 is a graph showing the USBL signal and the signal including the average position value (a) and random noise actually measured in the USBL and the average position value (b) in an XY plan view according to an embodiment of the present invention.
14 is a graph showing a position error (a) on the x-axis and a position error (b) on the y-axis, which are measured in the GPS, as another embodiment of the present invention.
FIG. 15 is a graph showing an actually measured position signal and an average position value in an XY plan view according to another embodiment of the present invention.
16 is a graph showing a histogram of a signal (a) in which random noise is included in a position error on the x axis measured by GPS and a signal (b) in which a random noise is included in a position error on the y axis, according to another embodiment of the present invention.
FIG. 17 is a graph showing a signal including random noise in a position signal actually measured in GPS and an average position value in an XY plan view according to another embodiment of the present invention. FIG.
18 is a graph showing the x-axis position error (a) and the y-axis position error (b) modeled by the Gaussian distribution function shown in Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Before describing the present invention in detail, terms and words used herein should not be construed in an ordinary or dictionary sense and should not be interpreted unconditionally, and in order for the inventor of the present invention to explain his invention in the best way It is to be understood that the concepts of various terms can be properly defined and used, and further, these terms and words should be interpreted in terms of meaning and concept consistent with the technical idea of the present invention.

That is, the terms used herein are used only to describe preferred embodiments of the present invention, and are not intended to specifically limit the contents of the present invention, It should be noted that this is a defined term.

Also, in this specification, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise, and it should be understood that they may include singular do.

Where an element is referred to as "comprising" another element throughout this specification, the term " comprises " does not exclude any other element, It can mean that you can do it.

Further, when it is stated that an element is "inside or connected to" another element, the element may be directly connected to or in contact with the other element, A third component or means for fixing or connecting the component to another component may be present when the component is spaced apart from the first component by a predetermined distance, It should be noted that the description of the components or means of 3 may be omitted.

On the other hand, it should be understood that there is no third component or means when an element is described as being "directly connected" or "directly connected" to another element.

Likewise, other expressions that describe the relationship between the components, such as "between" and "immediately", or "neighboring to" and "directly adjacent to" .

In this specification, terms such as "one side", "other side", "one side", "other side", "first", "second" Is used to clearly distinguish one element from another element, and it should be understood that the meaning of the element is not limited by such term.

It is also to be understood that terms related to positions such as "top", "bottom", "left", "right" in this specification are used to indicate relative positions in the drawing, Unless an absolute position is specified for these positions, it should not be understood that these position-related terms refer to absolute positions.

Furthermore, in the specification of the present invention, the terms "part", "unit", "module", "device" and the like mean a unit capable of handling one or more functions or operations, Or software, or a combination of hardware and software.

In this specification, the same reference numerals are used for the respective components of the drawings to denote the same reference numerals even though they are shown in different drawings, that is, the same reference numerals throughout the specification The symbols indicate the same components.

In the drawings attached to the present specification, the size, position, coupling relationship, and the like of each constituent element of the present invention may be partially or exaggerated or omitted or omitted for the sake of clarity of description of the present invention or for convenience of explanation May be described, and therefore the proportion or scale may not be rigorous.

Further, in the following description of the present invention, a detailed description of a configuration that is considered to be unnecessarily blurring the gist of the present invention, for example, a known technology including the prior art may be omitted.

FIG. 1 is a block diagram of an integrated navigation system for water for realizing a position measurement error correction method according to the present invention, which includes a mother ship 100, a remote control unmanned submersible 200, and an autonomous unmanned submersible 300 .

The bus 100 includes a USBL transceiver 110 and a GPS 120. The remote controlled unmanned submersible 200 includes a USBL responder 210, a first inertial measurement unit (IMU) 220, (DVL) 230, a first attitude heading reference system (AHRS) and a depth sensor 240, and a first extended Kalman filter 250 do.

The autonomous unmanned submersible 300 includes a USBL transponder 310, a second inertial sensor unit (IMU) 320, a second velocity sensor (DVL) 330, a second yaw angle- An attitude heading reference system (AHRS), a depth sensor 340, and a second extended Kalman filter 350.

Referring to FIG. 1, the components and functions of the integrated navigation navigation system for implementing the position measurement error correction method of the underwater vehicle 200, 300 according to the present invention will be described below.

The first and second inertial sensors 220 and 320 measure the acceleration and the angular velocity by detecting the inertial force of the motion of each of the mobile objects 200 and 300 at a cycle of 100 Hz and output the first and second velocity sensors 230 and 330, Measures the speed of each of the mobile objects 200 and 300 at a cycle of 5 Hz.

The first and second bow angle-posture sensors and depth sensors 240 and 340 measure the azimuth and attitude of each of the underwater vehicles 200 and 300 and the depth of each of the underwater vehicles 200 and 300, respectively.

The operation of measuring the position of the moving objects 200 and 300 using the USBL is as follows.

When the remote control unmanned submersible 200 transmits a response signal generation command to the remote controlled unmanned submersible 200 on a line of the bus 100 through a cable as a responder mode or a USBL transponder mode, Generates an acoustic pulse and the USBL transceiver 110 of bus 100 receives it.

At this time, the USBL transceiver 110 calculates the delay time required to receive the acoustic pulse signal, converts the distance to the remote control pilotless submersible 200, calculates the signal receiving angle in the two orthogonal directions, .

Also, the three-dimensional relative position of the remote controlled unmanned submersible 200 is calculated, and the absolute position of the remote controlled unmanned submersible 200 is calculated in consideration of the position of the bus 100 acquired through the GPS 120.

On the other hand, in the case of the autonomous unmanned submersible 300, when the USBL transceiver 110 transmits an interrogation signal as a transponder mode, the USBL transponder 310 receives the interrogation signal, generates an acoustic pulse, The transceiver 110 receives it.

At this time, the USBL transceiver 110 calculates the delay time required for receiving the acoustic pulse signal, converts the round trip distance to the autonomous unmanned submersible 300, calculates the signal reception angle in two orthogonal directions, .

In addition, the relative three-dimensional relative position of the autonomous unmanned submersible 300 is calculated, and the absolute position of the autonomous unmanned submersible 300 considering the position of the bus bar 100 acquired through the GPS 120 is converted.

For example, assuming that the position of the mobile object 200, 300 is 1500 m from the bus 100, the time = distance / sound speed and the sound velocity is about 1500 m / The delay time of the acoustic pulse signal calculated in the first embodiment is 1 second for the responder mode remote controlled unmanned submersible 200 and 2 seconds for the transponder mode remote controlled unmanned submersible 200 and the autonomous unmanned submersible 300 .

Accordingly, the bus 100 receives signals from the underwater vehicles 200 and 300 at intervals of about 3 seconds in order to prevent the interference of the signals received from the underwater vehicles 200 and 300.

The operation of normalizing the position signal having the non-normal distribution error of the underwater mobile object 200, 300 measured using the USBL is as follows.

FIG. 2 is a graph showing a signal including a USBL signal and random noise measured in the integrated navigation navigation system shown in FIG. 1 in an X-Y plan view.

Fig. 3 is a graph showing a position error (a) measured in the integrated navigation navigation system shown in Fig. 1 and a signal (b) including random noise in a histogram.

As shown in FIG. 3 (a), the present invention is characterized in that the X-directional truncation error ΔX and the Y-directional cutoff for the USBL measurement accuracy depend on the latitude of the underwater vehicle 200, As a result of calculation of the error DELTA Y, the USBL output signal has a noise characteristic with a normal distribution error from a macroscopic point of view, but has a non-normal distribution signal characteristic from a microscopic point of view.

Random noise that is uniformly distributed in a predetermined section of FIG. 2 is generated, and random noise is added to the X, Y signals of the USBL measured as shown in the following equation.

Here, X _USBL (t _k) and Y _USBL (t _k) is the x-axis position in time (t _k) and y-axis position, ΔX and ΔY is the cutting error of the respective X- direction and a Y- direction, , and rn is random noise.

As shown in FIG. 3 (b), as a result of adding the random noise in the X-direction and the Y-direction to the USBL position measurement value of the submersible 200 and 300, the error signal of the USBL position measurement is not only macroscopic From the microscopic point of view, it can be seen that it has a normal distribution characteristic.

4 is a flowchart showing the operation of the method for correcting the characteristics of the USBL signal measured in the integrated navigation navigation system shown in FIG.

5A to 5C are diagrams illustrating a flow of a USBL signal measured according to a time delay in the integrated navigation navigation system shown in FIG. 1. In the case of a remote controlled unmanned submersible 200 in which an underwater vehicle is operated as a responder (a (B) for a remote controlled unmanned submersible 200 operated as a transponder, and (c) for an autonomous unmanned submersible 300 operated as a transponder.

FIG. 6 is a view showing a position of a moving object underwater compensated for time delay in the integrated navigation navigation system shown in FIG. 1. FIG.

The operation of the characteristic correction method of the USBL signal measured in the method of correcting the position measurement error of the moving object 200, 300 according to the present invention will now be described with reference to FIGS. 1 to 6. FIG.

First, the latitude and longitude of the moving objects 200 and 300 are read from the first and second extended Kalman filters 250 and 350 (S100), and the cutting errors DELTA X and DELTA Y in the X- An error? Y is set (S150).

The number of signal receiving outliers (alpha) is reset (S200), and the measured USBL signal is waited (S250).

The measured USBL signal is applied to calculate a signal range and a delay time required to receive the signal (S300).

(S350) and reads the speed data of the underwater vehicle 200, 300 in two directions (e.g., the north direction and the east direction) orthogonal to the navigation data memory (S400).

The moving position of the moving object 200 during the calculated delay time is calculated (S450).

The measured value of the USBL signal at time _tk is corrected as follows (S500).

First, when the underwater vehicle is a remote controlled unmanned submersible 200 operated by a USBL responder, the USBL signal processing time interval (T _USBL ), the sound transmission average acoustic velocity (V _a ), the first inertia sensor (J = T _USBL /? T) of the USBL signal processing time interval, and the sampling time interval (? T, about 0.01 second) of the USBL signal processing time interval.

When the acoustic pulse is generated in the USBL responder 210 of the remote controlled unmanned submersible 200 at the time ( ₁ ), the USBL transceiver 200 of the bus 100 whose distance (slant range, R ₁ ) Lt; RTI ID = 0.0 > 110 < / RTI >

At time (3), the position and distance R ₁ of the remote control unmanned submersible 200 are calculated to calculate a 100 Hz count number (j ₁ = R ₁ / V _a δt).

Next, the positional change amounts? X _GPS and? Y _GPS of the bus bar 100 during the time (3) to time (4) are measured to correct the positional change of the bus bar (100).

The position of the remote control unmanned submersible 200 during time (1) to time (3) is calculated by the following equation (2).

At this time, the travel distance of the remote controlled unmanned submersible 200 is calculated by integrating the speed of the remote controlled unmanned submersible 200 with respect to time.

Here, X _USBL (t _k) and Y _USBL (t _k) are each time (t _k) The x-axis position and the y-axis position measured by the USBL in, ΔX _GPS and ΔY _GPS is the measured bus via GPS the amount of change in position (100), V _E (t _ki), V _N (t _ki) represents the east and the remote control unmanned submersible 200, the speed of the north direction at each time (t _ki).

Next, when the underwater vehicle is the remote controlled unmanned submersible 200 operated by the USBL transponder, the USBL signal processing time interval (T _USBL ), the sound transmission average sound velocity (V _a ), the first inertia An initial value for the sampling time interval (? T, about 0.01 second) of the sensor 220 and the 100 Hz count number (j = T _USBL /? T) of the USBL signal processing time period is set.

When the acoustic pulse is generated in the USBL transceiver 110 of the bus 100 in the time period (1), the sound is generated in the remote controlled unmanned submersible 200 with the distance (R ₁ ) Receives a pulse and outputs a response signal.

The acoustic pulse response signal is received at the USBL transceiver 110 of the bus 100 where the distance R ₂ is distant from the remote control unmanned submersible 200 at the predetermined time ③ at which the bus 100 travels.

At time (4), the reciprocating distance (R ₁ + R ₂ ) / 2 is calculated, and the position of the remote control unmanned submersible 200 at time (2) is measured using this.

,

로 근사화할 수 있으므로 100 Hz 카운트 숫자는 (j₁=R₁/V_aδt) 로 산출된다.At this time, if the remote controlled unmanned submersible 200 is operated at a sufficiently deep water depth,

,

, The 100 Hz count number is calculated as (j ₁ = R ₁ / V _a δt).

Next, the positional change amounts? X _GPS and? Y _GPS of the bus bar 100 during the time (3) to time (4) are measured to correct the positional change of the bus bar (100).

The position of the remote control unmanned submersible 200 during time (2) to time (4) is calculated by the following equation (3).

Here, X _USBL (t _k) and Y _USBL (t _k) are each time (t _k) The x-axis position and the y-axis position measured by the USBL in, ΔX _GPS and ΔY _GPS is the measured bus via GPS the amount of change in position (100), V _E (t _ki), V _N (t _ki) represents the east and the remote control unmanned submersible 200, the speed of the north direction at each time (t _ki).

Finally, when the underwater vehicle is an autonomous unmanned submersible 300 operated as a USBL transponder, the USBL signal processing time interval (T _USBL ), the sound transmission average acoustic velocity (V _a ), the second inertia sensor (Latency,? T _a ) for asynchronous transfer mode (ATM) data reception and the time required to receive the USBL signal in the asynchronous transfer mode (? T, about 0.01 second) the initial value for the 100 Hz count number (j _a =? t _a /? t) of the latency is set.

When the acoustic pulse is generated in the USBL transceiver 110 of the bus 100 in the time period (1), the acoustic pulse is generated in the autonomous unmanned submersible 300 with the distance (R ₁ ) And outputs a response signal.

The USBL transceiver 110 of the bus 100 whose distance R ₂ is away from the autonomous unmanned submersible 300 receives the acoustic pulse response signal at the predetermined time ③ at which the bus line 100 has moved.

At time (4), the reciprocating distance (R ₁ + R ₂ ) / 2 is calculated and the position of the autonomous unmanned submersible 300 is measured at time (2).

When the bus line 100 starts to transmit the measured USBL position data of the autonomous unmanned submersible 300 to the autonomous unmanned submersible 300 through the asynchronous transfer mode, , The USBL position data is confirmed at time (6) by terminating the data reception.

,

로 근사화할 수 있으므로 100 Hz 카운트 숫자는 (j₁=R₁/V_aδt)로 산출된다.At this time, if the autonomous unmanned submersible 300 is operated at a sufficiently deep water depth,

,

, The 100 Hz count number is calculated as (j ₁ = R ₁ / V _a δt).

Next, the positional change amounts? X _GPS and? Y _GPS of the bus bar 100 during the time (3) to time (4) are measured to correct the positional change of the bus bar (100).

The position of the autonomous unmanned submersible 300 during the time (2) to the time (6) is calculated by the following equation (4).

Here, X _USBL (t _k) and Y _USBL (t _k) are each time (t _k) USBL the x-axis position and the y-axis position measured by the in, ΔX _GPS and ΔY _GPS is measured through the GPS position variation of the bus bar (100) V _E (t _ki), V _N (t _ki) shows an autonomous unmanned submarine 300, the speed of the east and north directions at each time (t _ki).

In the case of (a) the remote controlled unmanned submersible 200 operated as a USBL responder, (b) the remote controlled unmanned submersible 200 operated as a USBL transponder, (b) the autonomous In the case of the unmanned submersible 300, as shown in FIG. 6, the measured position (dash-and-dotted line) of the underwater vehicle is compensated for the time delay by applying the position measurement error correction method according to the present invention, (Dotted line) and positional compensation (solid line) after elapsed.

On the other hand, after correcting the measured value of the USBL signal at time _tk in step S500, a measurement error of the USBL signal is calculated (S550), and an outlier, that is, (S600).

If a signal reception failure occurs, the number of defective signal reception is increased by one, the error of the measured USBL signal is discarded, and an error covariance matrix is propagated (S650).

At this time, the operation of discarding the error of the measured USBL signal is as follows.

The measurement signals exceeding the threshold error range n *? (N = 3 to 5) are removed, and the number (?) Of signal reception failures is counted.

Here,? Represents the standard deviation of the error.

The measurement error covariance characteristic of the USBL due to the signal reception failure is corrected by the following expression (5).

Here, R _k is the measurement error at time (t _k) covariance, R is the measurement error covariance, α denotes a signal reception failure number.

If no signal reception failure occurs in step S600, the following Extended Kalman filtering operation is performed.

That is, random noise uniformly distributed on the x-axis position (X _USBL ) and the y-axis position (Y _USBL ) is added (S700) and the measurement error covariance is adjusted (S750).

After the signal reception failure is reset (S800), it is determined whether the extended Kalman filtering operation is continued (S850). If it is determined that the extended Kalman filtering operation is to be continued, the flow returns to step S500.

FIG. 7 is an operation flowchart for explaining an extended Kalman filtering operation of the USBL signal characteristic correction method shown in FIG. 4 in detail.

The extended Kalman filtering operation in the position measurement error correction method of the moving object 200, 300 according to the present invention will be described in detail with reference to FIGS. 1 to 7 as follows.

The distance from the bus 100 converted by the USBL transceiver 110 to the underwater vehicle 200 and 300 and the absolute position of the underwater vehicle 200 and 300 converted from the GPS 120 are received and initialized at step S501.

The first and second inertial sensors 220 and 320 detect the inertial force of the motions of the remote controlled autonomous submersible 200 and autonomous unmanned submersible 300 to provide acceleration and angular velocity at step S502.

The first and second extended Kalman filters 250 and 350 receive the acceleration and angular velocity data of the underwater vehicles 200 and 300 from the first and second inertial sensors 220 and 320, A strap-down inertial navigation algorithm for calculating data such as position, velocity, and posture is driven to calculate an estimated distance of the mobile object 200, 300 in consideration of the changed position information of the bus 100 (S503).

The basic operation principle of the strap-down inertial navigation algorithm is to form a reference navigation coordinate system using a gyro output that measures a rotational angular velocity of a moving vehicle 200, 300, compensate for a gravitational acceleration component from an accelerometer output on a reference navigation coordinate system, 300 to calculate the current position of the moving object 200, 300 by obtaining the velocity of the moving object 200, 300 and integrating the velocity of the moving object 200 and 300 again.

That is, the strap-down inertial navigation algorithm can calculate the estimated navigation data such as the speed, position, and posture of the underwater vehicle 200, 300 without external adjustment, thereby avoiding external interference or disturbance, It is advantageous that the navigation data can be calculated without being interrupted by such a problem.

However, since the calculated value is an estimation value, there is a problem that the error is accumulated over time. Therefore, the following error correction process is required.

The estimated distance of the underwater vehicle 200, 300 calculated by the first and second extended Kalman filters 250, 350 is applied and the error covariance matrix is propagated (S504).

The Kalman gain is calculated for the USBL (S505), the Kalman gain is calculated for the first and second speed sensors 230 and 330 (S506), and the error covariance matrix is updated (S507).

The data necessary for calculating the Kalman gain for the first and second velocity sensors 230 and 330 includes velocity data of each of the underwater vehicles 200 and 300 measured by the first and second velocity sensors 230 and 330, The asynchronous multirate computed by the strap-down inertial navigation algorithm in the attitude and depth data S508 of each of the underwater vehicles 200 and 300 measured at the first and second bow-attitude sensors and the depth sensors 240 and 340, Speed data and posture and depth data.

After receiving the sum of the velocity data and the attitude and depth data to update the state estimation data for velocity and depth (S509), the Kalman gain for the first and second velocity sensors 230 and 330 and the first and second The Kalman gain for the bow angle-posture sensor and the depth sensor 240, 340 is calculated (S506).

The data required for calculating the Kalman gain for USBL is calculated by adding the sum of the position data calculated through the strap-down inertial navigation algorithm to the position data of each of the underwater mobile objects 200 and 300 measured by the USBL transceiver 110 (S510) to be.

The sum of the position data is received to correct the time delay error (S550), and it is determined whether an outlier, that is, a signal reception failure has occurred (S600).

Random noises uniformly distributed on the x-axis position (X _USBL ) and the y-axis position (Y _USBL ) are added and the measurement error covariance (R _k ) is adjusted (S700).

If a signal reception failure occurs, the number of defective signal reception is increased by one, the error of the measured USBL signal is discarded, and an error covariance matrix is propagated (S650).

After updating the state estimation data for the first and second velocity sensors 230 and 330 using the adjusted measurement error covariance (S701), the flow returns to step S505 for calculating the Kalman gain for USBL, and at the same time, 1 and the second speed sensor 230, 330 and returns to the step S503 to drive the strap-down inertia navigation algorithm.

The strap-down inertial navigation algorithm receives the estimated error covariance matrix propagated in step S504 and receives the state estimation update data for the first and second speed sensors 230 and 330, , And 300, and outputs the corrected data.

In step S506, a Kalman gain for the first and second velocity sensors 230 and 330 and the first and second bow angle-posture sensors and the depth sensors 240 and 340 is calculated. Then, in step S507, To update the error covariance matrix, and returns to step S504 to propagate the error covariance matrix.

In this way, according to the present invention, by using the acceleration and angular velocity data of the moving objects 200 and 300 measured by the first and second inertial sensors 220 and 320 and the position information of the bus 100, And 300 and corrects the error of the navigation data using the position data of the underwater vehicle 200 and 300 measured by the USBL transceiver 110. [

The first and second extended Kalman filters 250 and 350 used in this case correct the estimated distance by indirect feedback.

That is, the bus 100 and the underwater vehicle 200, 300 are considered to be moving through the strap-down inertial navigation algorithm, which removes the noise included in the data and estimates a new result by using the past measurement data and the new measurement data It works recursively by continuously updating the data.

The first and second extended Kalman filters 250 and 350 used in the present invention are applicable not only to linear motion but also to nonlinear models.

FIG. 8 is a graph simulating the position (a) on the x-axis and the position (b) on the y-axis of the autonomous unmanned submersible 300 measured in the USBL according to the elapse of time as an embodiment of the present invention.

9 is a graph showing a position error (a) on the x-axis and a position error (b) on the y-axis, which are measured in the USBL, in the histogram according to an embodiment of the present invention.

FIG. 10 is a graph showing the position (a) on the x-axis where a random error is added to the USBL position measurement value on the x-axis of the autonomous unmanned submersible shown in FIG. 8 and the y-axis position (b) where random error is added to the y- It is a graph that is compared with the passage of time.

11 is a graph showing a position error (a) on the x-axis and a position error (b) on the y-axis, to which a random error is added, as shown in FIG.

12 is a graph showing the x-axis position error (a) and the y-axis position error (b) modeled by the Gaussian distribution function of the random error shown in Fig.

FIG. 13 is a graph showing the USBL signal actually measured in the USBL and the signal including the average position value (a) and the random noise and the average position value (b) in the XY plane according to one embodiment of the present invention.

In FIGS. 8 to 11, the autonomous unmanned submersible 300 is located at a depth of 1441 m on the surface of the sea bottom, and the resolution is 1.98 m in the north-south direction (dy) and 1.5 m in the east-west direction (dx).

FIGS. 10 and 11 show results obtained by adding regularly distributed random noise of dx and dy sizes to the USBL measurement position signals X and Y shown in FIGS. 8 and 9, respectively. FIG. 12 shows the random error shown in FIG. We estimated the covariance by fitting it with the distribution function.

As shown in FIGS. 8 and 9, the USBL measurement position signals X and Y have non-normal distribution signal characteristics from a microscopic viewpoint due to ΔX, which is the X-direction cutting error, and ΔY, which is the Y-direction cutting error.

However, as a result of adding the normal distribution random noise to the USBL measurement position signals X and Y respectively, as shown in FIGS. 10 to 12, the error signal of the USBL position measurement is not only macroscopic but also microscopic As shown in Fig.

In particular, as shown in FIG. 13 (a), the USBL signals actually measured in the USBL are distributed around the average position value, while the USBL signals including the random noise are distributed It can be seen that they are concentrated around the position value.

This is because the error signal of the USBL position measurement has a normal distribution and the measurement distance of the underwater vehicle 200 or 300 increases to improve the accuracy of the position measurement of the underwater vehicle 200 or 300 even if the error is accumulated over time .

FIG. 14 is a graph showing a positional error (a) on the x-axis and a positional error (b) on the y-axis, which are measured in the GPS 120, as another embodiment of the present invention.

FIG. 15 is a graph showing an actually measured position signal and an average position value in the GPS 120 in an X-Y plan view according to another embodiment of the present invention.

16 shows a signal (a) including a random noise in the x-axis position error measured by the GPS 120 and a signal (b) including the random noise in the y-axis position error in a histogram Graph.

17 is a graph showing a signal including a random noise in a position signal actually measured by the GPS 120 and an average position value in an X-Y plan view according to another embodiment of the present invention.

18 is a graph showing the x-axis position error (a) and the y-axis position error (b) modeled by the Gaussian distribution function shown in Fig.

Since the output signal of the GPS 120 also has a cutting error similar to that of the USBL measurement position signal, it exhibits the same deterministic signal characteristic as that of the USBL signal in a microscopic range.

That is, as shown in Figs. 14 and 15, the GPS measurement position signals X and Y have non-normal distribution signal characteristics from a microscopic viewpoint due to ΔX, which is the X-direction cutting error and Y, .

However, as a result of adding the normal distribution random noise to the GPS measurement position signals X and Y, respectively, as shown in Figs. 16 to 18, the error signal of the USBL position measurement is not only macroscopic but also microscopic As shown in Fig.

In particular, as shown in FIG. 15, the GPS 120 signal actually measured by the GPS 120 is distributed around the average position value, whereas the GPS 120, which includes random noise, It can be seen that the signal is concentrated around the average position value.

This is because the error signal of the position measurement of the GPS 120 has a normal distribution and the measurement distance of the underwater vehicle 200 or 300 increases so that the position of the underwater vehicle 200 or 300 Which means that the precision is improved.

As described above, according to the present invention, when a position measurement signal of a moving object is deterministically given by a truncation error, a random noise is added to a measurement signal within a truncation error range, There is provided a method of correcting a position measurement error of an underwater vehicle in which a position measurement signal of a moving object in a water can have a Gaussian normal distribution even in a microscopic region by correcting the measurement error.

In this way, when the position measurement value and the position estimation value of the moving object exceed the threshold value of the error normal value, it is determined that the signal reception is defective and the measurement error covariance is excluded from the update of the measurement signal, It is possible to overcome the limitation of USBL in which defects occur intermittently or continuously.

In addition, when the inertial system and the USBL signal are integrated, the error signal of the USBL position measurement is modeled as a random noise having a normal distribution, so that the error of the navigation system incorporating the GPS position signal is reduced and the accuracy of the underwater navigation system is improved do.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

In addition, since the present invention can be embodied in various other forms, the present invention is not limited by the above description, and the above description is intended to be a complete description of the present invention, It will be understood by those of ordinary skill in the art that the present invention is only provided to fully inform the person skilled in the art of the scope of the present invention and that the present invention is only defined by the claims of the claims.

Claims (13)

A USBL transceiver for receiving an acoustic pulse signal and measuring a USBL signal, and a GPS receiver including a USBL responder for generating the acoustic pulse signal and an underwater navigation system for tracking the position of an underwater navigation system having an extended Kalman filter In the position measurement error correction method of the present invention,
(a) reading the latitude and longitude of the underwater vehicle from the extended Kalman filter, and setting a cutoff error in the X-direction and the Y-direction of the measured USBL signal;
(b) resetting the number of signal reception defects and waiting for the measured USBL signal;
(c) calculating a signal range and a signal reception delay time by receiving the measured USBL signal, and calculating a delay count;
(d) reading the speed data of the underwater vehicle from the navigation data memory, and calculating a position of movement of the underwater vehicle during the calculated delay time;
(e) correcting a measured value of the USBL signal at a predetermined time;
(f) calculating a measurement error of the corrected USBL signal and determining whether the signal reception failure has occurred;
(g) increasing a count of the number of defective signal reception by one when a signal reception failure occurs, and discarding the error of the measured USBL signal; And
(h) performing an extended Kalman filtering operation to cause the corrected USBL signal to have a normal distribution if signal reception failure does not occur;
≪ / RTI >
A method for correcting position measurement error of underwater mobile objects.
The method according to claim 1,
The underwater vehicle
A remote control unmanned submersible vehicle having the USBL responder, the first inertial sensor, the first speed sensor, the first bow angle-posture sensor, and the first depth sensor; And
An autonomous unmanned submersible vehicle having a USBL transponder, a second inertial sensor, a second speed sensor, a second bow angle-posture sensor, and a second depth sensor;
≪ / RTI >
A method for correcting position measurement error of underwater mobile objects.
3. The method of claim 2,
The step (e)
If the underwater vehicle is a remote controlled unmanned submersible operated by a USBL responder,
(T _USBL ), the sound transmission average sound velocity (V _a ), the sampling time interval (? t) of the first inertia sensor and the sampling time interval (? t) of the USBL signal processing time interval Setting an initial value for a 100 Hz count number (j = T _USBL /? T);
(e-2) receiving an acoustic pulse in the USBL transceiver when the acoustic pulse is generated in the USBL responder, the predetermined distance (R ₁ ) away from the bus line;
(e-3) calculating the position of the remote controlled unmanned submersible and the distance (R ₁ ) to calculate a 100 Hz count number (j ₁ = R ₁ / V _a δt);
(e-4) measuring a position change amount (DELTA X _GPS , DELTA Y _GPS ) of the bus line to correct a change in position of the bus line; And
(e-5) calculating the position of the remote controlled unmanned submersible according to the following equation;

(Above and X _USBL (t _k) and the Y _USBL (t _k) are each time (t _k) The measured x through the USBL in axial position and the y-axis position, the ΔX _GPS and the ΔY _GPS is measured by the GPS the location and amount of change in the bus bars, wherein the V _E (t _ki) and the V _N (t _ki) is the velocity of the remote control unmanned submersible to the east and the north direction at each time (t _ki))
≪ / RTI >
A method for correcting position measurement error of underwater mobile objects.
3. The method of claim 2,
The step (e)
In the case that the underwater vehicle is a remote controlled unmanned underwater vehicle operated as a USBL transponder,
(T _USBL ), the sound transmission average sound velocity (V _a ), the sampling time interval (? t) of the first inertia sensor and the sampling time interval (? t) of the USBL signal processing time interval Setting an initial value for a 100 Hz count number (j = T _USBL /? T);
(e-2) receiving an acoustic pulse from the USBL transceiver having a predetermined distance (R ₁ ) away from the bus line when the acoustic pulse is generated in the USBL responder, and outputting a response signal;
(e-3) receiving the response signal by the USBL transceiver in which the bus is moved and the remote control unmanned submersible has a distance R ₂ from the bus line;
(e-4) The reciprocating distance (R ₁ + R ₂ ) / 2 is calculated using the distance R ₁ and the distance R ₂ , and the position of the remote controlled UAV is measured. (j ₁ = R ₁ / V _a隆 t);
(e-5) measuring a position change amount (DELTA X _GPS , DELTA Y _GPS ) of the bus line to correct a change in position of the bus line; And
(e-6) calculating the position of the remote controlled unmanned submersible by the following equation;

(Above and X _USBL (t _k) and the Y _USBL (t _k) are each time (t _k) The measured x through the USBL in axial position and the y-axis position, the ΔX _GPS and the ΔY _GPS is measured by the GPS the location and amount of change in the bus bars, wherein the V _E (t _ki) and the V _N (t _ki) is the velocity of the remote control unmanned submersible to the east and the north direction at each time (t _ki))
≪ / RTI >
A method for correcting position measurement error of underwater mobile objects.
3. The method of claim 2,
The step (e)
When the underwater vehicle is an autonomous unmanned underwater vehicle operated as a USBL transponder,
(T _USBL ), a sound wave transmission average acoustic velocity (V _a ), a sampling time interval (? t) of the second inertia sensor, and an asynchronous transmission mode data reception time (e-1) Setting an initial value for the signal processing time (? T _a ) and the 100 Hz count number (j _a =? T _a /? T) of the time required for receiving the USBL signal in the asynchronous transfer mode;
(e-2) receiving an acoustic pulse from the USBL transceiver having a predetermined distance (R ₁ ) away from the bus line when the acoustic pulse is generated in the USBL responder, and outputting a response signal;
(e-3) receiving the response signal by the USBL transceiver in which the bus line is moved and the autonomous unattended submersible is separated from the bus line by a distance R ₂ ;
(e-4) calculating a reciprocating distance (R ₁ + R ₂ ) / 2 using the distance R ₁ and the distance R ₂ and measuring the position of the autonomous unmanned submersible;
(e-5) If the bus transmits the measured position data of the autonomous unmanned submersible to the autonomous unmanned submersible in the asynchronous transfer mode, the measured position data of the autonomous unmanned submersible at the predetermined time To calculate a 100 Hz count number (j ₁ = R ₁ / V _a隆 t);
(e-6) measuring a position change amount (DELTA X _GPS , DELTA Y _GPS ) of the bus line to correct a positional change of the bus line; And
(e-7) calculating the position of the autonomous unmanned submersible by the following equation;

(Above and X _USBL (t _k) and the Y _USBL (t _k) are each time (t _k) The measured x through the USBL in axial position and the y-axis position, the ΔX _GPS and the ΔY _GPS is measured by the GPS the location and amount of change in the bus bars, wherein the V _E (t _ki) and the V _N (t _ki) is the speed of the autonomous unmanned submarine to the east and the north direction at each time (t _ki))
≪ / RTI >
A method for correcting position measurement error of underwater mobile objects.
The method according to claim 1,
After the step (g)
Propagating an error covariance matrix and returning to step (b);
Lt; RTI ID = 0.0 > 1, < / RTI &
A method for correcting position measurement error of underwater mobile objects.
The method according to claim 1,
The step of discarding the error of the measured USBL signal
Removing the measured USBL signal exceeding a threshold error range n *? (N = 3 to 5,? Is the standard deviation of the error);
Counting the number of signal reception defects; And
Correcting a measurement error covariance characteristic of the USBL signal due to the signal reception failure using the following equation;

(A measurement error covariance R _k at the time (t _k), wherein R is the measurement error covariance, wherein α is the number of signal reception failure)
≪ / RTI >
A method for correcting position measurement error of underwater mobile objects.
3. The method of claim 2,
The step (h)
(h-1) receiving and initializing the distance from the USBL transceiver to the underwater vehicle or the absolute position of the underwater vehicle converted by the GPS;
(h-2) detecting the inertial force of the motion of the first and second inertial sensors to the underwater vehicle to provide an acceleration and an angular velocity;
(h-3) calculating the estimated distance of the underwater vehicle by driving the strap-down inertial navigation algorithm with the acceleration and the angular velocity being applied by the extended Kalman filter;
(h-4) propagating the error covariance matrix by receiving the estimated distance;
(h-5) calculating a Kalman gain for the first and second velocity sensors and a Kalman gain for the USBL and updating the error covariance matrix;
≪ / RTI >
A method for correcting position measurement error of underwater mobile objects.
9. The method of claim 8,
In the step (h-5)
The data necessary for calculating the Kalman gain for the first and second velocity sensors is
Calculated by the strap-down inertial navigation algorithm, on the velocity data of each of the underwater vehicles measured by the first and second velocity sensors, and the depth data of each of the underwater vehicles measured by the first and second depth sensors, Rate rate data and depth data. ≪ RTI ID = 0.0 >
A method for correcting position measurement error of underwater mobile objects.
10. The method of claim 9,
After the step (h-5)
(h-6) updating the state estimation data for the velocity and the depth by receiving the sum of the velocity data and the depth data; And
(h-7) calculating a Kalman gain for the first and second velocity sensors and a Kalman gain for the first and second depth sensors;
Lt; RTI ID = 0.0 > 1, < / RTI &
A method for correcting position measurement error of underwater mobile objects.
11. The method of claim 10,
In the step (h-5)
The data necessary for calculating the Kalman gain for the USBL is
And the position data of each of the underwater mobile bodies measured by the USBL transceiver is the sum of the position data calculated through the strap-down inertial navigation algorithm.
A method for correcting position measurement error of underwater mobile objects.
12. The method of claim 11,
After the step (h-7)
Receiving a sum of the position data to correct a time delay error, and determining whether the signal reception failure has occurred;
Adding random noise to the position on the x-axis and the position on the y-axis when the signal reception failure does not occur, and adjusting the measurement error covariance;
Increasing the number of defective signal reception by one when the signal reception failure occurs and discarding the error of the measured USBL signal and propagating the error covariance matrix; And
Updating the state estimation data for the first and second velocity sensors using the adjusted measurement error covariance, and returning to step S50 calculating a Kalman gain for the USBL;
Returning to step S100 driving the strap-down inertia navigation algorithm by correcting errors of the state estimation update data for the first and second velocity sensors;
The strap-down inertial navigation algorithm receives the propagated error covariance matrix and the state estimation update data for the first and second speed sensors with the error corrected, and corrects the position, velocity, and attitude data of the underwater vehicle step;
Lt; RTI ID = 0.0 > 1, < / RTI &
A method for correcting position measurement error of underwater mobile objects.
A USBL transceiver for receiving an acoustic pulse signal and measuring a USBL signal, and a GPS receiver including a USBL responder for generating the acoustic pulse signal and an underwater navigation system for tracking the position of an underwater navigation system having an extended Kalman filter In the position measurement error correction method of the present invention,
(a) reading the latitude and longitude of the underwater vehicle from the extended Kalman filter, and setting a cutoff error in the X-direction and the Y-direction of the measured USBL signal;
(b) resetting the number of signal reception defects and waiting for the measured USBL signal;
(c) calculating a signal range and a signal reception delay time by receiving the measured USBL signal, and calculating a delay count;
(d) reading the speed data of the underwater vehicle from the navigation data memory, and calculating a position of movement of the underwater vehicle during the calculated delay time;
(e) correcting a measured value of the USBL signal at a predetermined time;
(f) calculating a measurement error of the corrected USBL signal and determining whether the signal reception failure has occurred;
(g) increasing a count of the number of defective signal reception by one when a signal reception failure occurs, and discarding the error of the measured USBL signal; And
(h) performing an extended Kalman filtering operation to cause the corrected USBL signal to have a normal distribution if signal reception failure does not occur;
Lt; / RTI >
Wherein the extended Kalman filter corrects the measured value of the USBL signal in a indirect feedback scheme for updating data in consideration of movement of the bus and the underwater vehicle.
A method for correcting position measurement error of underwater mobile objects.

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