KR100979286B1 - Apparatus and method for detecting distance and orientation between objects under water - Google Patents

Abstract

PURPOSE: An apparatus and a method for measuring the distance and orientation between objects under water are provided to precisely measure the distance and the orientation between objects in a submerged environment with a noise and a position change of a target object due to turbulent flow. CONSTITUTION: A transmission sensor(130) is installed under water and transmits a detection signal. A receiving sensor(140) is installed on a submerged object(170) and receives the detected signal. A transmitter(120) transmits the phase of the inverted detected signal to the transmission sensor. A receiver(150) receives the detected signal of the receiving sensor. A controller(110) obtains cross correlation of the received detection signal and the transmitted detection signal. The distance and orientation of the object are measured.

Description

Apparatus and Method for detecting distance and orientation between objects under water}

One embodiment of the present invention relates to an apparatus and a method for measuring distance and azimuth, and more particularly, to invert a phase of a detection signal under water and calculate a cross correlation between a transmission signal and a phase signal to calculate the distance between objects in the water. And an apparatus and method for measuring orientation.

In general, in the sound detector for detecting an acoustic signal in the water to detect the exact position of the sound source, the method of detecting the sound wave in the water is an active sonar that emits sound energy and receives the reflected sound energy from the object. There is a (Sonar) method and a passive sonar method that receives only acoustic energy radiated from other sound sources.

A sonar system is a hydrophone or sound detector in a narrow sense, and it has some differences depending on the situation of the sea, but uses the property of propagating at the speed of about 1,500 m / s in the sea and reflecting back to the object. . The acoustic detector type corresponds to the active sonar, and the hydrophone type corresponds to the passive sonar.

The former includes an acoustic detector and an acoustic probe, which emits ultrasonic waves as short intermittent sounds and measures the distance to the object by measuring the time it takes to hit the object and reflect it back. It also rotates a transmitter to detect its direction. It is actually the same as radar's PPI scope method, and the distance is measured on the CRT and the bearings are engraved on the circumference so that the scan line rotates with the rotation of the transmitter. Objects appear as light spots to detect distance and orientation.

There is a hydrophone in the latter, and the orientation can be known from the time difference of the arrival sound by combining a plurality of directional hearing instruments. When the conditions are good, this type of sonar is capable of detecting ships up to 160 km in length. The sound is different depending on the type and type of ship, and even the types of ships can be identified. They are mainly used near the surface of the sea, and there is a variable temperature layer in which the structure of the water temperature is complicated, so that the wave length and the speed of the sound wave change, which limits the effective distance.

These sonar systems measure the propagation time of a sound wave by comparing the transmission waveform with the reception waveform, and measure the distance between objects. It is not easy to find the starting point of the received signal because it is burned, and there is a problem that does not distinguish which signal is the received signal.

An object of the present invention, an apparatus and method for measuring the underwater distance and azimuth to increase the accuracy of the sonar by accurately grasping the position and orientation of the sonar, such as sonar in the underwater environment changes in the position of the sonar itself To provide.

It is another object of the present invention to provide an underwater distance and azimuth with a high measurement accuracy that is less affected by noise by phase inverting a signal for measuring the position and orientation of a positional changed object when there is a positional change of an object to be measured in an underwater environment. It is to provide an apparatus and method for measuring.

In order to achieve the above object, an apparatus for measuring underwater distance and azimuth according to an embodiment of the present invention includes: a transmission sensor installed in the water and transmitting a detection signal; A reception sensor installed at an object underwater to receive the detection signal; A transmitter for transmitting the inverted phase of the detection signal to the transmitter; A receiver receiving the detection signal detected by the reception sensor; And a controller for obtaining a cross correlation between the transmitted detection signal and the received detection signal and measuring the distance and orientation of the object with respect to the transmission sensor.

The apparatus further includes a graphical user interface (GUI) for displaying measurement information including the transmitted detection signal, the received detection signal, a cross correlation function of the detection signal, and the distance and orientation of the object. It is preferable.

The apparatus may further include an amplifier provided between the transmitter and the transmitter, the amplifier amplifying the detection signal attenuated during transmission from the transmitter to the transmitter.

The transmission sensor is characterized in that the sound wave transmission sensor for converting the detection signal in the form of an electrical signal generated by the transmission unit in the form of a sound wave signal.

The receiving sensor may independently receive the transmitted sound wave signal, and include a first receiving sensor and a second receiving sensor spaced apart at regular intervals.

Each of the first receiving sensor and the second receiving sensor may receive the transmitted detection signal at different azimuth angles.

The transmitter may invert the phase of the detection signal at least once, and vary the amplitude or frequency of the detection signal before and after the phase inversion.

According to an aspect of the present invention, there is provided a method of measuring underwater distance and azimuth, including: transmitting a detection signal toward an object by reversing a detection signal at least once in order to measure distance and aquatic underwater; Calculating a location information including a distance and a direction of the object with respect to a transmission position by obtaining a cross correlation between the transmitted detection signal and the received detection signal when the detection signal is received by the object; And displaying the calculated position information to the user.

In the transmitting step, the amplitude or frequency of the detection signal is changed before and after the time point of the phase inversion.

The transmitting step is characterized in that for changing the electrical detection signal to a sound wave-type detection signal using a sound wave transmission sensor and transmitting.

The calculating step may include a first receiving step of receiving a first received detection signal for the transmitted detection signal by using a first reception sensor; And a second reception step of receiving a second reception detection signal for the transmission detection signal by using a second reception sensor, wherein the first reception sensor and the second reception sensor are fixedly spaced apart by a third distance. It is characterized by being installed.

The calculating step may include calculating a first distance between the transmission sensor and the first reception sensor based on the first reception detection signal and the transmitted detection signal; And calculating a second distance between the transmission sensor and the second reception sensor based on the second reception detection signal and the transmitted detection signal.

The first distance calculating step may include obtaining a cross correlation between the first received detection signal and the transmitted detection signal, and based on the first received detection signal, the first received detection signal reaching the first reception sensor from the transmission sensor. Save an hour,

The calculating of the second distance may include obtaining a cross correlation between the second received detection signal and the transmitted detection signal, and based on the second received detection signal, the second received detection signal reaching the second reception sensor from the transmission sensor. It is characterized by finding 2 hours.

In the calculating step, the distance and azimuth of the object with respect to the transmission sensor may be obtained based on the first, second, and third distances.

The apparatus and method for measuring underwater distance and azimuth according to embodiments of the present invention use a phase-inverted detection signal, so that the distance between objects in an underwater environment with high fluctuations in position and noise due to factors such as turbulence, etc. There is an effect that can accurately measure the orientation.

In addition, the apparatus and method for measuring the underwater distance and azimuth according to the embodiments of the present invention in combination with a sonar system (SONAR) system to measure the distance and azimuth of the sonar itself in the underwater state to measure the precision of the sonar measurement system It can increase the effect.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible, even if shown on different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related well-known configuration or function may obscure the gist of the present invention, the detailed description is omitted, and the singular terminology may include a plurality of concepts. . In addition, the following will describe a preferred embodiment of the present invention, but the technical idea of the present invention is not limited thereto and may be variously modified and modified by those skilled in the art.

Figure 1 shows a functional block diagram of a device for measuring the distance and azimuth of an underwater object according to an embodiment of the present invention, Figure 2 is an embodiment of the present invention in combination with a sonar system applied to a ship An example is shown.

Referring to FIG. 1, the apparatus 100 for measuring the distance and azimuth of an underwater object according to an embodiment of the present invention includes a transmission sensor 130 installed in the water and transmitting a detection signal; A reception sensor (140) installed in the object (170) underwater to receive the detection signal; A transmitter 120 for transmitting the inverted phase of the detection signal to the transmitter; A receiver 150 receiving the detection signal detected by the reception sensor; And a controller 110 obtaining a cross correlation between the transmitted detection signal and the received detection signal and measuring the distance and orientation of the object with respect to the transmission sensor.

The object 170 may be an object that is elevated in a general environment as well as an underwater environment. The object may be a sonar that detects an object in an underwater environment. The sonar may be used in combination with a carrier such as a ship, and in this case, since the position of the sonar varies due to turbulence, etc., knowing the exact position of the sonar may increase the measurement accuracy of the sonar system.

The apparatus 100 may include a graphical user interface (GUI) 160 displaying measurement information including the transmitted detection signal, the received detection signal, a cross correlation function of the detection signal, and the distance and azimuth of the object. And an amplifier (AMP) 121 installed between the transmitter and the transmitter to amplify the detection signal attenuated during transmission from the transmitter to the transmitter.

The transmission sensor 130 converts the detection signal in the form of an electrical signal generated by the transmission unit into a sound wave signal form and transmits the sound signal, and a sound wave transmission sensor may be used. Therefore, an example of the sound wave transmission sensor may be a transducer that transmits an electric signal underwater by converting an electrical signal into an acoustic signal.

The transmitter 120 transmits a detection signal to the transmission sensor by wire, at least one phase inversion of the detection signal and varying the amplitude or frequency of the detection signal before and after the phase inversion.

As described above, when the object is in an underwater environment such as a sonar, the initial position may be changed due to turbulence, etc., and also there is a lot of noise, so it is difficult to accurately know the starting point of the received detection signal. 120, it is possible to phase-invert the transmission detection signal to accurately find the starting point of the received detection signal during cross-correlation calculation of the transmitted detection signal and the received detection signal.

The receiving sensor 140 includes a first receiving sensor 141 and a second receiving sensor 142 formed at regular intervals, and the first and second receiving sensors independently of the transmitted sound wave signals. Receive. In this case, each of the first receiving sensor and the second receiving sensor has a substantially perpendicular connection line between the connecting line of both receiving sensors and the transmitting sensor so that the transmitted detection signal can be received at different azimuth angles. Arranged to achieve.

2, when the apparatus 100 for measuring the distance and orientation of the underwater object according to an embodiment of the present invention described above is applied to the sonar system of the vessel 180, the control unit 110, The transmitter 120, the receiver 150, and the GUI 160 are mounted on a ship and positioned on the water, and the transmission sensor 130, the amplifier 121, and the reception sensor 140 are located underwater.

In particular, the object is the sonar 170 is located in the water, the receiving sensor (141, 142) is fixedly spaced apart at regular intervals on the top of the sonar 170. Therefore, the phase-inverted detection signal transmitted from the transmitting sensor is received by two receiving sensors spaced apart from the top of the sonar, and the receiving unit transmits the received detection signal to the controller.

Therefore, the control unit calculates the cross correlation between the two signals using the transmitted detection signal and the first and second reception detection signals received at each of the two reception sensors. As a result, it is possible to measure the time when two reception detection signals reach each reception sensor from the transmission sensor, and the distance between each reception sensor from the transmission sensor can be known from each arrival time. Finally, according to the second law of the cosine of the trigonometric function, the distance between the two receiving sensors and the distance between the receiving sensor and the sonar and the transmitting sensor based on the distance between the transmitting sensor and each receiving sensor. You can see. The detection signal phase-inverted by the transmitter may be determined as a point in time at which the cross correlation is calculated from the phase inversion at the time of calculating the sound propagation time, thereby becoming very resistant to noise.

Sonar testing at sea can be moved by turbulence or other reasons, and when the device 100 is combined with a ship's sonar system, it is known how far the sonar's distance or orientation changes within a predictable range. This can increase the measurement accuracy of the sonar system.

Figure 3 shows a flow chart of a method for measuring the distance and azimuth of an underwater object according to an embodiment of the present invention.

Referring to FIG. 3, the method for measuring underwater distance and azimuth according to an embodiment of the present invention includes: inverting a detection signal at least once in phase to transmit a distance and azimuth to an object in order to measure distance and azimuth in water (S10); When the detection signal is received at the object, calculating cross-correlation between the transmitted detection signal and the received detection signal and calculating position information including the distance and azimuth of the object with respect to a transmission position (S20 to S60). ); And displaying the calculated position information to the user (S60).

In the transmitting step S10, the amplitude or frequency of the detection signal is changed before and after the timing of the phase reversal, and the electrical detection signal is changed into a sound wave type detection signal using a sound wave transmission sensor and transmitted.

In the calculating step, a first reception sensor receives a first reception detection signal for the transmitted detection signal, a second reception sensor receives a second reception detection signal for the transmission detection signal (S20), In this case, the first receiving sensor and the second receiving sensor are fixedly spaced apart by a third distance.

The calculating may include calculating a first distance between the transmission sensor and the first reception sensor based on the first reception detection signal and the transmitted detection signal (S30), and transmitting the second reception detection signal and the transmitted signal. A second distance between the transmitting sensor and the second receiving sensor is calculated based on the detection signal (S40).

Here, in order to calculate the first distance (S33), first, a cross correlation degree of the first received detection signal and the transmitted detection signal is obtained (S31), and based on this, the first received detection signal is transmitted to the transmission sensor. It is necessary to find (S32) a first time from which the first reception sensor is reached. In order to calculate the second distance (S43), first, a cross correlation degree of the second received detection signal and the transmitted detection signal is obtained (S41), and based on this, the second received detection signal is obtained from the transmission sensor. It is necessary to obtain a second time of reaching the second receiving sensor (S42). The distance and orientation to the object are calculated based on the first, second, and third distances (S50).

Hereinafter, an example of calculating the distance and orientation of the sonar using the apparatus and method described above in the environment shown in FIG. 2 will be described in detail.

4A and 4B show measured distances and azimuths in the case where there is no positional variation of the target object and when the positional variation of the target object occurs, respectively. FIG. 5 illustrates a phase inverted detection signal generated by an apparatus for measuring the distance and azimuth of an underwater object according to an embodiment of the present invention, and a screen of the display unit showing the same, and FIG. 6 illustrates an embodiment of the present invention. The cross-correlation signal between the transmission signal and the reception signal in the apparatus for measuring the distance and azimuth of the underwater object according to the present invention is shown.

First, the equipment is operated on the vessel 180, and sensors (transmission and reception sensors) connected to the equipment are operated underwater. Here, the equipment is composed of a controller 110, a transmitter 120, a receiver 150 and a GUI 160, the equipment transmits the distance direction measurement signal generated by the user to the sound wave transmission sensor, the transmission sensor The sound wave is transmitted at 130 and the transmitted signals are received by the first and second receiving sensors 141 and 142 mounted on the target, respectively.

As shown in FIG. 5, the transmitter 120 inverts a transmission signal and changes the frequency and amplitude of the signal before and after the phase inversion time.

The first and second received signals received by the reception sensor 140 may calculate a sound wave propagation time by performing a cross-correlation operation of Equation (1) together with a transmission signal.

---------------------------(1)

---------------------------(One)

Here, one of the functions f (t) or g (t) becomes a transmission signal, and the other corresponds to a reception signal. Thus, the two signals f (t) and g (t) are multiplied by two functions that are shifted by the delay time and integrated over a sufficiently long time period.

This results in the maximum value at the time when the two signals are most similar, and this characteristic can be used to derive the propagation time of sound waves. In this case, the reason for transmitting the phase signal by inverting the phase is that when the phase is reversed than when the phase is not reversed, the graph value of the maximum value of the correlation function is sharp, so that the result can be obtained cleanly and the noise is strong. Because.

In the upper left graph on the screen of FIG. 6, a red graph is a reception signal of the first reception sensor 141, a green graph is a reception signal of the second reception sensor 142, and a graph at the upper right is a transmission signal and a first signal. 1 is a cross-correlation calculation value of a received signal, and a graph below shows a cross-correlation calculation value of a transmission signal and a second reception signal.

Through the above operation, it is possible to derive the sound wave propagation times T1 and T2 reaching each of the first and second receiving sensors. The sound wave propagation time is obtained by subtracting ½ of the graph X-axis length from the X-coordinate of the maximum value of each graph.

In this embodiment, since the X-axis value of the maximum value is 0.11542 sec and the total X-axis length is 0.2 sec, the sound wave propagation time is 0.11542-0.1 = 0.01542. Therefore, multiplying the sound wave speed in water by 1500m / s, the distance between the transmitting sensor and the first receiving sensor is derived, 0.01542 x 1500 = 23.13m. When the sound wave propagation time and distance between the transmitting sensor and the second receiving sensor are calculated in the above manner, the sound wave propagation time is 0.01542 and the distance is 23.13 m. The sound wave propagation time and distance in each of the first and second receiving sensors are shown in box 1 and box 2 of FIG. 6.

If the distance between the transmission sensor and the first reception sensor calculated as described above is L1, the distance between the transmission sensor and the second reception sensor L2, and the distance between the already known first and second reception sensors is L3. You can draw a triangle with three sides, L1, L2, and L3. Therefore, three angles formed by two adjacent sides of the triangle can be obtained by the second cosine law for the triangle of Equation (2) below.

--------------------------------(2)

--------------------------------(2)

Here, a, b, and c are lengths of three sides forming a triangle, and A is an angle formed by two sides b and c.

Referring to box 3 of FIG. 6, it can be seen that the distance and orientation to the sonar are 23.1178 m and 2.842171 degrees, respectively.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 is a functional block diagram of an apparatus for measuring the distance and azimuth of an underwater object according to an embodiment of the present invention.

Figure 2 illustrates an application of an embodiment of the present invention installed on a ship in combination with a sonar system.

Figure 3 shows a flow chart of a method for measuring the distance and azimuth of an underwater object according to an embodiment of the present invention.

4A and 4B show measured distances and azimuths in the case where there is no positional variation of the target object and when the positional variation of the target object occurs, respectively.

5 is a diagram illustrating a phase-inverted detection signal generated by the apparatus for measuring the distance and azimuth of an underwater object according to an embodiment of the present invention, and a screen of the display unit showing the same.

FIG. 6 illustrates a cross-correlation signal between a transmission signal and a reception signal in a device for measuring the distance and azimuth of an underwater object according to an embodiment of the present invention, and a screen of a display unit showing the same.

Claims (14)

A transmission sensor installed in the water and transmitting a detection signal; A reception sensor installed at an object underwater to receive the detection signal; A transmitter for transmitting the inverted phase of the detection signal to the transmitter; A receiver receiving the detection signal detected by the reception sensor; And A control unit for obtaining a cross correlation between the transmitted detection signal and the received detection signal and measuring the distance and orientation of the object with respect to the transmission sensor Apparatus for measuring the underwater distance and azimuth comprising a. In claim 1 The apparatus further includes a graphical user interface (GUI) for displaying measurement information including the transmitted detection signal, the received detection signal, a cross correlation function of the detection signal, and the distance and orientation of the object. A device for measuring underwater distance and azimuth. In claim 1 or 2 The apparatus further includes an amplifier installed between the transmitter and the transmitter to amplify the detection signal attenuated during transmission from the transmitter to the transmitter. Device. The method of claim 1, The transmitting sensor is an apparatus for measuring underwater distance and azimuth, characterized in that the sound wave transmission sensor for converting the detection signal of the electrical signal generated by the transmission unit in the form of a sound wave signal. The method of claim 1, The receiving sensor independently receives the transmitted sound wave signal, the apparatus for measuring the underwater distance and azimuth comprising a first receiving sensor and a second receiving sensor formed spaced apart at regular intervals. The method of claim 5, And each of the first and second receiving sensors receives the transmitted detection signal at different azimuth angles. The method of claim 1, And the transmitting unit inverts the detection signal at least once and varies the amplitude or frequency of the detection signal before and after the phase inversion. Phase-inverting the detection signal toward the object at least once in order to measure distance and orientation underwater; Calculating the location information including the distance and azimuth of the object with respect to a transmission position by obtaining a cross correlation between the transmitted detection signal and the received detection signal when the detection signal is received from the object; And Displaying the calculated location information to a user. Method for measuring the underwater distance and azimuth comprising a. The method of claim 8, And wherein said transmitting step changes the amplitude or frequency of said detection signal before and after said phase inversion. The method of claim 8 The transmitting step is a method for measuring the underwater distance and azimuth, characterized in that for transmitting the electric wave detection signal to the detection signal of the acoustic wave form using a sound wave transmission sensor. The method of claim 8, The calculating step, A first reception step of receiving a first reception detection signal with respect to the transmitted detection signal by using a first reception sensor; And A second reception step of receiving a second reception detection signal for the transmission detection signal by using a second reception sensor; And the first receiving sensor and the second receiving sensor are fixedly spaced apart from each other by a third distance. The method of claim 11, The calculating step, Calculating a first distance between the transmission position and the first reception sensor based on the first reception detection signal and the transmitted detection signal; And Calculating a second distance between the transmission position and the second reception sensor based on the second reception detection signal and the transmitted detection signal; Method for measuring the underwater distance and azimuth comprising a. The method of claim 12, The first distance calculation step may include obtaining a cross correlation between the first received detection signal and the transmitted detection signal, and based on the first received detection signal, the first received detection signal reaching the first reception sensor from the transmission position. Save an hour, The calculating of the second distance may include obtaining a cross correlation between the second received detection signal and the transmitted detection signal, and based on the second received detection signal, the second received detection signal reaching the second reception sensor from the transmission position. A method of measuring underwater distance and azimuth, characterized by obtaining two hours. The method of claim 13, And the calculating step obtains the distance and azimuth of the object with respect to the transmission position based on the first, second, and third distances.

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