KR102804716B1 - Beam forming method and apparatus - Google Patents

Abstract

A beam forming method for target detection in a beam forming device may be provided. The beam forming method includes a step of acquiring reception signals of a plurality of first sensors arranged at a first interval for a target signal transmitted in a horizontal direction of the target, a step of setting a plurality of virtual sensors so that the sensor intervals are closer than the first interval, a step of generating time delay signals of the plurality of first sensors by compensating for time delays of the plurality of first sensors to the reception signals of the plurality of first sensors, respectively, a step of generating time delay signals of the plurality of virtual sensors by using the time delay signals of the plurality of first sensors, a step of generating reception signals of the plurality of virtual sensors by reverse compensating for time delays of the plurality of virtual sensors to the time delay signals of the plurality of virtual sensors, and a step of forming a beam for each detection direction from the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors.

Description

Beam forming method and apparatus {BEAM FORMING METHOD AND APPARATUS}

The present invention relates to a beam forming method and device.

When detecting a target using an array sensor, spatial aliasing may occur in a band exceeding the design frequency of the array when a beam pattern is derived according to a beam forming technique.

Spatial aliasing occurs when the same phase as the target's actual direction appears in a different direction when forming a beam according to the detection direction in the array sensor. And as the frequency band increases above the design frequency, the frequency of spatial aliasing occurring within the detection direction increases. Therefore, the design frequency of the array sensor is set to satisfy the frequency band for detecting the target.

The sensor spacing within the array sensor varies depending on the design frequency for target detection and the sound velocity of the medium in the detection environment. Generally, the sensor spacing is set to the value obtained by dividing the wavelength of the signal for the design frequency by 2. Therefore, in order to increase the design frequency, the sensor spacing of the array sensor must be reduced. If an array sensor with a higher design frequency than the existing array sensor is designed, a relatively large number of sensors must be placed because the existing array shape size must be maintained in order to maintain the same detection performance in the same frequency band, and thus the signal processing load increases. In addition, due to spatial constraints in which the sensors can be placed, there is a limit to the range in which the design frequency can be increased.

At least one of the embodiments can provide a beam forming method and device capable of reducing spatial aliasing in a frequency band higher than a design frequency while maintaining the shape of an array sensor.

According to one embodiment, a beam forming method for target detection in a beam forming device may be provided. The beam forming method includes a step of acquiring reception signals of a plurality of first sensors arranged at a first interval for a target signal transmitted in a horizontal direction of the target, a step of setting a plurality of virtual sensors so that the sensor intervals are closer than the first interval, a step of generating a time delay signal of the plurality of first sensors by compensating for a time delay of the plurality of first sensors to the reception signals of the plurality of first sensors, respectively, a step of generating a time delay signal of the plurality of virtual sensors by using the time delay signals of the plurality of first sensors, a step of generating a reception signal of the plurality of virtual sensors by reverse compensating for a time delay of the plurality of virtual sensors to the time delay signals of the plurality of virtual sensors, and a step of forming a beam for each detection direction from the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors.

The step of generating the delay signal of the plurality of first sensors may include the step of calculating the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors for the target signal transmitted in the horizontal direction of the target.

The step of forming a beam according to the detection direction may include a step of compensating for the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors to the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors, respectively, to generate a time delay signal of the plurality of first sensors and a time delay signal of the plurality of virtual sensors, and a step of generating beam data according to the detection direction from the time delay signals of the plurality of first sensors and the time delay signals of the plurality of virtual sensors.

The step of calculating the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors may include the step of detecting the horizontal direction of the target through beam formation using the reception signals of the plurality of first sensors, and the step of calculating the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors based on the horizontal direction of the target, the sensor interval, and the position of each sensor.

The step of generating the delay signals of the plurality of virtual sensors may include the step of generating the delay signals of the plurality of virtual sensors through linear interpolation from the delay signals of the plurality of first sensors.

The above linear interpolation may include two-dimensional linear interpolation over space and time or over space and frequency.

According to another embodiment, a beam forming device for target detection can be provided. The beam forming device includes a reception processing unit that obtains reception signals received from a plurality of first sensors arranged at a first interval with respect to a target signal transmitted from a target, a virtual sensor setting unit that sets at least one virtual sensor between each of the first sensors, a virtual signal generation unit that compensates for time delays of the plurality of first sensors to the reception signals of the plurality of first sensors, generates time delay signals of the plurality of first sensors through linear interpolation using the time delay signals of the plurality of first sensors, and generates reception signals of the plurality of virtual sensors from the time delay signals of the plurality of virtual sensors, and a beam forming processing unit that generates beam data for each detection direction from the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors.

The beam forming device may further include a target direction detection unit that detects the horizontal direction of the target through beam formation according to detection direction from reception signals received from the plurality of first sensors, and the virtual signal generation unit may calculate the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors based on the horizontal direction of the target, the sensor interval, and the position of each sensor.

The beam forming processing unit can compensate for the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors in the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors, respectively, and add the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors, for which the delay time has been compensated, for each detection direction to generate beam data for each detection direction.

The above virtual signal generation unit can generate reception signals of the plurality of virtual sensors each having a time delay of the plurality of virtual sensors by inversely compensating for the time delay of the plurality of virtual sensors to the time delay signals of the plurality of virtual sensors.

According to at least one embodiment of the present invention, spatial aliasing in a band higher than a design frequency can be reduced while maintaining the shape of the array sensor.

According to at least one embodiment of the present invention, the characteristics of a signal generated in a direction other than the target direction that the observer intends to detect can be reduced, and thus, complex detection information generated by spatial aliasing in a frequency band higher than the design frequency of the array sensor becomes relatively simple, making it easier for the observer to determine whether or not the target exists.

Figure 1 is a drawing showing a conventional beam forming method.
Fig. 2 is a drawing showing a beam forming method according to an embodiment.
FIG. 3 is a flowchart illustrating a beam forming method for reducing spatial aliasing according to an embodiment.
Figure 4 is a diagram showing the settings of a virtual sensor and the delay time of an actual sensor according to an embodiment.
FIG. 5 is a diagram showing the delay time compensation of an actual sensor and a virtual time delay signal of a virtual sensor according to an embodiment.
Fig. 6 is a diagram showing a virtual reception signal of a virtual sensor according to an embodiment.
FIG. 7 is a drawing showing a beam forming device according to one embodiment.
Figure 8 shows an example of a simulation environment.
Figure 9 is a diagram showing the reception signal of the array sensor measured in the simulation environment illustrated in Figure 8.
FIG. 10 is a drawing showing a beam pattern according to a conventional beam forming method using the reception signal illustrated in FIG. 9.
Fig. 11 is a diagram showing an example of a virtual sensor according to an embodiment.
Figure 12 is a diagram showing the reception signals of the actual sensor and virtual sensor shown in Figure 11 in a simulation environment.
FIG. 13 is a drawing showing a beam pattern according to a beam forming method of an embodiment using the reception signal illustrated in FIG. 11.
FIG. 14 is a graph showing the beam pattern at 5 kHz in the beam patterns shown in FIG. 10 and FIG. 13.
FIG. 15 is a graph showing the beam pattern at 7 kHz in the beam patterns shown in FIG. 10 and FIG. 13.
Figure 16 is a diagram showing the reception signals of an actual sensor and a virtual sensor with a sensor spacing of λ/8 in a simulation environment.
FIG. 17 is a drawing showing a beam pattern according to a beam forming method of an embodiment using the reception signal illustrated in FIG. 16.
FIG. 18 is a graph showing the beam pattern at 4 kHz in the beam patterns shown in FIG. 10, FIG. 13, and FIG. 17.
FIG. 19 is a drawing showing a beam forming device according to another embodiment.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in order to clearly describe the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are assigned similar drawing reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only being "directly or physically connected," but also being "indirectly or non-contactingly connected" with other elements in between, or being "electrically connected."

Additionally, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

Additionally, in the flowcharts described with reference to the drawings in this specification, the order of operations may be changed, multiple operations may be merged, an operation may be split, and a specific operation may not be performed.

Now, a beam forming method and device according to an embodiment will be described in detail with reference to the drawings.

Figure 1 is a drawing showing a conventional beam forming method.

Referring to FIG. 1, the existing beam forming method may include a step of obtaining a reception signal of each sensor (S110), a step of compensating for phases according to detection direction (S120), a step of generating beam data (S130), and a step of outputting beam data (S140).

The beam forming device can obtain a reception signal received from a target at each sensor of the array sensor (S110).

In order to generate a beam aimed at a specific detection direction, a process of matching and adding the phases of the reception signals of each sensor is required. The beam forming device can compensate for the phase between the reception signals of each sensor for each detection direction (S120). The beam forming device calculates the time delay of the reception signal of each sensor based on a specific sensor of the array sensor for each detection direction, and delays the reception signal of each sensor based on the calculated time delay, thereby matching the phases of the reception signals of each sensor for each detection direction.

The beam forming device can generate beam data for each detection direction by adding up the reception signals of each sensor for each detection direction (S130).

The beam forming device outputs beam data for each detection direction (S140). Target detection can be performed through the output of beam data for each detection direction, and the target direction can be detected through target detection.

The sensor spacing d of the array sensor can be set as in mathematical expression 1.

Here, λ represents the wavelength of the signal for the target detection frequency, and can be expressed as in mathematical expression 2.

Here, f _d represents the target detection frequency, and c represents the medium sound speed of the detection environment.

As the frequency band increases higher than the design frequency of the array sensor, the occurrence frequency of spatial aliasing within the detection direction increases. Therefore, the design frequency of the array sensor can be set so as to satisfy the frequency band for detecting the target.

Looking at mathematical expressions 1 and 2, if the sensor spacing of the array sensor is reduced, the design frequency of the array sensor can be increased, but more sensors are required, and thus the signal processing load can increase. In addition, due to spatial constraints in which each sensor can be placed, there is a limit to increasing the design frequency of the array sensor.

According to an embodiment, a beam forming method capable of reducing spatial aliasing for a frequency band higher than a design frequency while maintaining the shape of an array sensor can be provided.

Fig. 2 is a drawing showing a beam forming method according to an embodiment.

Referring to Fig. 2, the beam forming device can detect the delay through beam forming according to the detection direction (S210). Through the steps described in Fig. 1, beam data according to the detection direction can be generated, and the target direction can be detected through the output of beam data according to the target direction.

Next, the beam forming device can perform beam forming to reduce spatial aliasing occurring in a frequency band higher than the design frequency of the array sensor by using the detected target direction (S220).

FIG. 3 is a flowchart illustrating a beam forming method for reducing spatial aliasing according to an embodiment, and FIG. 4 is a diagram illustrating settings of a virtual sensor and a delay time of an actual sensor according to an embodiment.

Referring to FIGS. 3 and 4, the beam forming device can set the virtual sensors (30) so that the sensor spacing becomes dense (S310). In some embodiments, the beam forming device can set at least one virtual sensor (30) between the sensors (10, 20) of the array sensors. The sensor spacing d between the two sensors (10, 20) can be set based on mathematical expression 1. In some embodiments, if one virtual sensor (30) is set between the two sensors (10, 20), the sensor spacing can be d/2. In some embodiments, if three virtual sensors (30) are set between the two sensors (10, 20), the sensor spacing can be d/4. In FIG. 3, for convenience, it is illustrated that one virtual sensor (30) is positioned between the two sensors (10, 20) and the two sensors (10, 20).

Below, in order to distinguish between the sensor (10, 20) of the array sensor and the virtual sensor (30), the sensor (10, 20) of the array sensor is named as the actual sensor.

The beam forming device can calculate the delay time of the actual sensor (10, 20) and the virtual sensor (30) for the target signal (received signal) of the target direction θ (S320).

The delay time of each sensor for the target signal (received signal) of the target direction θ can be expressed as in mathematical expression 3.

Here, can represent the delay time for the mth sensor of the ith received signal. c represents the medium sound speed of the detection environment. d can represent the sensor spacing.

For example, referring to FIG. 4, when setting the actual sensor (10) as a reference in the array sensor, the delay time of the actual sensor (10) with m=1 can be set to 0, the time delay of the virtual sensor (30) with a sensor interval of d/2 and m=2 can be set to (d/2c)sinθ _i , and the time delay of the actual sensor (20) with a sensor interval of d/2 and m=3 can be set to (d/c)sinθ _i .

In this way, the reception signal of each actual sensor of the array sensor has a time delay as shown in mathematical expression 3 with respect to the target orientation θ.

FIG. 5 is a diagram showing the delay time compensation of an actual sensor and a virtual time delay signal of a virtual sensor according to an embodiment.

Referring to FIGS. 3 and 5, the beam forming device can generate a time delay signal [S _{' 1} (t), S _{' 2} (t)] of each actual sensor (10, 20) by using the delay time of each actual sensor (10, 20) from the reception signal [S ₁ (t), S ₂ (t)] of each actual sensor (10, 20) (S330). The beam forming device can compensate for the delay time of each actual sensor (10, 20) for the reception signal [S ₁ (t), S ₂ (t)] of each actual sensor (10, 20) to match the phase between the reception signals of each actual sensor (10, 20) for the target direction θ. The time delay signal [S' ₁ (t), S' ₂ (t)] of each real sensor (10, 20) may be a reception signal of each real sensor (10, 20) with the delay time of each real sensor (10, 20) compensated for.

That is, through this process, the phases of the delay signal [S _{' 2} (t)] for the reception signal [S ₂ (t)] of the actual sensor (20) and the delay signal [S' ₁ (t)] for the reception signal [S ₁ (t)] of the actual sensor (10) can become identical, as shown in FIG. 5.

The beam forming device can generate a virtual time delay signal [S' il (t)] of a virtual sensor (30) from the time delay signals [S' ₁ (t), S' ₂ (t)] of each real sensor ( ₁₀ , 20) using an interpolation method (S340). Here, the interpolation method can represent a two-dimensional linear interpolation for the space and time of the sensor. In some embodiments, if beam forming is performed in the frequency domain, the interpolation method can be applied according to the space of the sensor and the frequency of the signal.

The virtual time delay signal [S' _il (t)] of the virtual sensor (30) is a signal in which the time delay of the virtual sensor (30) is compensated. Therefore, as shown in FIG. 5, the phase of the virtual time delay signal [S' _il (t)] of the virtual sensor (30) is the same as the phase of the time delay signal [S _{' 2} (t)] for the reception signal [S ₂ (t)] of the real sensor (20) and the phase of the time delay signal [S' ₁ (t)] for the reception signal [S ₁ (t)] of the real sensor (10).

Fig. 6 is a diagram showing a virtual reception signal of a virtual sensor according to an embodiment.

Referring to FIGS. 3 and 6, the beam forming device can generate a virtual reception signal [S _i1 (t)] of the virtual sensor (30) by inversely compensating for the delay time of the virtual sensor (30) with respect to the virtual time delay signal [S' _il (t)] of the virtual sensor (30) (S350). That is, the virtual reception signal of the virtual sensor (30) can be a reception signal of the virtual sensor (30) delayed by the delay time of the virtual sensor (30).

By doing so, the beam forming device can obtain the reception signal [S ₁ (t), S ₂ (t)] of each real sensor (10, 20) and the virtual reception signal [S _i1 (t)] of the virtual sensor (30), and the reception signal [S _i1 (t)] of each real sensor (10, 20) and the virtual reception signal [S _i1 (t)] of the virtual sensor (30) may have a delay time of each of the real sensors (10, 20) and the virtual sensor (30), as illustrated in FIG. 6.

Next, the beam forming device compensates for the delay time of each sensor according to the detection direction by receiving signals [S ₁ (t), S ₂ (t)] of each real sensor (10, 20) and virtual receiving signals [S _i1 (t)] of the virtual sensor (30), so as to generate time delay signals of each real sensor (10, 20) and virtual sensor (30) according to the detection direction (S360). That is, the beam forming device aligns the phases of the receiving signals [S ₁ (t), S ₂ (t)] of each real sensor (10, 20) and the virtual receiving signals [S _i1 (t)] of the virtual sensor (30) according to the detection direction.

The beam forming device can generate beam data for each detection direction by combining the time delay signals [S' ₁ (t), S' ₂ (t), S' _i1 (t)] of each real sensor (10, 20) and virtual sensor (30) for each detection direction (S370).

In this way, by additionally adding the time delay signal [S' _{i1 (t)] of the virtual sensor (30) to the time delay signal [S' 1 (} t), S' ₂ (t)] of each actual sensor (10, 20) for each detection direction to generate beam data, spatial aliasing in a frequency band higher than the design frequency of the array sensor can be reduced. Accordingly, complex detection information generated by spatial aliasing in a frequency band higher than the design frequency becomes relatively simple, making it easier for an observer to determine whether a target exists.

FIG. 7 is a drawing showing a beam forming device according to one embodiment.

Referring to FIG. 7, the beam forming device may include an array sensor (710), a receiving processing unit (720), a target direction detection unit (730), a virtual sensor setting unit (740), a virtual signal generation unit (750), and a beam forming processing unit (760).

The array sensor (710) may include a plurality of actual sensors. A plurality of array sensors may be arranged at equal intervals.

The reception processing unit (720) can obtain the reception signal of each actual sensor of the array sensor (710).

The target direction detection unit (730) can detect the target direction by processing the reception signal of each actual sensor of the array sensor (710). The target direction detection unit (730) can detect the target direction by forming a beam for each detection direction from the reception signal of each actual sensor of the array sensor (710).

The virtual sensor setting unit (740) can set at least one virtual sensor between actual sensors so that the sensor spacing becomes dense.

The virtual signal generation unit (750) can generate a virtual reception signal of a virtual sensor using a reception signal of an actual sensor. The virtual signal generation unit (750) can generate a virtual reception signal of a virtual sensor using the method described based on FIGS. 3 to 6.

The beam forming processing unit (760) can form beams according to the detection direction using the reception signal of the actual sensor and the virtual reception signal of the virtual sensor.

Then, the effect of reducing spatial aliasing in the beam forming method according to the embodiment will be described with reference to FIGS. 8 to 18.

Figure 8 shows an example of a simulation environment.

Referring to Fig. 8, the simulation environment was assumed to be underwater with a sound speed of 1500 m/s, and an array sensor having 9 sensors with a design frequency (Fd) of 4 kHz and a sensor spacing of λ/2 (=0.1875 m) was placed in free space. At this time, it was assumed that the sampling frequency was 16,384 Hz, and a target signal in the frequency band of 1 to 7 kHz was received at a horizontal direction (θ) of 30° based on the array sensor, and omnidirectional white noise was set to be received together with the target signal.

Figure 9 is a diagram showing the reception signal of the array sensor measured in the simulation environment illustrated in Figure 8.

In Fig. 9, the vertical axis can represent the index of the actual sensor.

The time-dependent reception signals of nine actual sensors measured in the simulation environment illustrated in Fig. 8 are shown in Fig. 9.

When beam data is formed according to the beam shape method illustrated in Fig. 1 using the reception signals of the nine actual sensors illustrated in Fig. 9, it appears as illustrated in Fig. 10.

FIG. 10 is a drawing showing a beam pattern according to a conventional beam forming method using the reception signal illustrated in FIG. 9.

When beam data is generated according to the beam shape method illustrated in FIG. 1 using the reception signals of nine actual sensors illustrated in FIG. 9, beam data according to frequency and beam steering direction (detection direction) can be derived as illustrated in FIG. 10.

Referring to Fig. 10, it can be confirmed that a signal with a constant correlation according to frequency is received at a horizontal orientation of 30° according to the existing beam forming. However, it can be seen that spatial aliasing occurs in an orientation area (910) other than the target orientation (i.e., horizontal orientation of 30°) in a frequency band of 4 kHz or higher.

FIG. 11 is a diagram showing an example of a virtual sensor according to an embodiment, and FIG. 12 is a diagram showing reception signals of the actual sensor and virtual sensor shown in FIG. 11 in a simulation environment.

Referring to FIG. 11, the beam forming device can set a virtual sensor between the actual sensors so that the sensor spacing becomes λ/4 in the simulation environment illustrated in FIG. 8. If one virtual sensor is set between two actual sensors, the sensor spacing can be λ/4, which can be tighter than the sensor spacing illustrated in FIG. 8.

The time-dependent reception signals of nine real sensors and eight virtual sensors are shown in Fig. 12.

When beam data is generated according to the beam shape method illustrated in FIG. 3 using the reception signals of the nine real sensors and eight virtual sensors illustrated in FIG. 12, it appears as illustrated in FIG. 13.

FIG. 13 is a drawing showing a beam pattern according to a beam forming method of an embodiment using the reception signal illustrated in FIG. 11.

When beam data is generated according to the beam shape method illustrated in FIG. 3 using the reception signals of the nine real sensors and eight virtual sensors illustrated in FIG. 12, beam data according to frequency and beam steering direction (detection direction) can be derived as illustrated in FIG. 13.

That is, the beam forming device can generate a delay signal by delaying the reception signals of the nine real sensors by a target direction of 30°, and perform two-dimensional linear interpolation from the space and time of the real sensors to the space and time of the virtual sensors using the nine delay signals, thereby generating virtual delay signals of the eight virtual sensors. Next, the beam forming device can derive virtual reception signals of the eight virtual sensors by inversely delaying the virtual delay signals of the eight virtual sensors by a target direction of 30°. The beam forming device can perform beam forming for each detection direction by integrating the reception signals of the nine real sensors and the virtual reception signals of the eight virtual sensors.

Referring to FIGS. 10 and 13 together, it can be confirmed that in the beam pattern illustrated in FIG. 13, spatial aliasing existing in an azimuth region (910) other than the target azimuth (i.e., horizontal azimuth 30°) is reduced in a frequency band of 4 kHz or more illustrated in FIG. 10. In addition, it can be confirmed that in the beam pattern illustrated in FIG. 13, a signal with constant correlation is maintained in the target azimuth 30°.

FIG. 14 is a graph showing a beam pattern at 5 kHz in the beam patterns shown in FIG. 10 and FIG. 13, and FIG. 15 is a graph showing a beam pattern at 7 kHz in the beam patterns shown in FIG. 10 and FIG. 13.

In FIGS. 14 and 15, the horizontal axis represents the detection direction, and the direction range from -200 degrees to 200 degrees is depicted. The vertical axis represents the beam intensity of the normalized beam pattern, and the normalized beam pattern is depicted based on the peak intensity at 30° of the target direction.

In FIG. 14, 1410 represents a normalized beam pattern at 5 kHz according to the conventional beam forming method illustrated in FIG. 1, and 1420 represents a normalized beam pattern at 5 kHz according to the beam forming method of the embodiment illustrated in FIG. 3.

In FIG. 15, 1510 represents a normalized beam pattern at 7 kHz according to the conventional beam forming method illustrated in FIG. 1, and 1520 represents a normalized beam pattern at 7 kHz according to the beam forming method illustrated in FIG. 3.

Referring to FIGS. 14 and 15, when comparing a beam pattern according to a conventional beam forming method with a beam pattern according to a beam forming method illustrated in FIG. 3 in a frequency band of 5 kHz and 7 kHz corresponding to 4 kHz or more, which is the design frequency of the array sensor, it can be confirmed that the beam pattern according to the beam forming method illustrated in FIG. 3 has reduced beam intensity and spatial aliasing in a direction area other than the target direction of 30°, i.e., the side lobe, compared to the beam pattern according to the conventional beam forming method.

Figure 16 is a diagram showing the reception signals of an actual sensor and a virtual sensor with a sensor spacing of λ/8 in a simulation environment.

The beam forming device can set three virtual sensors between the actual sensors so that the sensor spacing is λ/8 in the simulation environment illustrated in Fig. 8, and the reception signals of 24 virtual sensors and 9 actual sensors over time are presented as in Fig. 16.

When beam data is generated according to the beam shape method illustrated in Fig. 3 using the reception signals of the 9 real sensors and 24 virtual sensors illustrated in Fig. 16, it appears as illustrated in Fig. 17.

FIG. 17 is a drawing showing a beam pattern according to a beam forming method of an embodiment using the reception signal illustrated in FIG. 16.

When beam data is generated according to the beam shape method illustrated in FIG. 3 using the reception signals of the 9 real sensors and 24 virtual sensors illustrated in FIG. 16, beam data according to frequency and beam steering direction (detection direction) can be derived as illustrated in FIG. 17.

Referring to FIG. 10 and FIG. 17 together, it can be confirmed that in the beam pattern illustrated in FIG. 17, spatial aliasing existing in an azimuth region (910) other than the target azimuth (i.e., horizontal azimuth 30°) is reduced in a frequency band of 4 kHz or more illustrated in FIG. 10. In addition, it can be confirmed that in the beam pattern illustrated in FIG. 17, a signal with constant correlation is maintained in the target azimuth 30°.

FIG. 18 is a graph showing the beam pattern at 4 kHz in the beam patterns shown in FIG. 10, FIG. 13, and FIG. 17.

In Fig. 18, the horizontal axis represents the detection direction, and the detection range from -200 degrees to 200 degrees is depicted. The vertical axis represents the beam intensity of the normalized beam pattern, and the normalized beam pattern is depicted based on the peak intensity at 30° of the target direction.

In FIG. 18, 1810 represents a normalized beam pattern at 4 kHz in the beam pattern illustrated in FIG. 10, 1820 represents a normalized beam pattern at 4 kHz in the beam pattern illustrated in FIG. 13, and 1830 represents a normalized beam pattern at 4 kHz in the beam pattern illustrated in FIG. 17.

Referring to Fig. 18, it can be seen that as the beam spacing becomes tighter by setting virtual sensors between actual sensors, the beam intensity and spatial aliasing in the side lobe, i.e., in the azimuth area other than the target azimuth of 30°, are reduced.

FIG. 19 is a drawing showing a beam forming device according to another embodiment.

Referring to FIG. 19, the beam forming device (100) may represent a computing device in which the beam forming method described above is implemented.

The beam forming device (100) may include at least one of a processor (110), a memory (120), an input interface device (130), an output interface device (140), a storage device (150), and a network interface device (160). Each of the components may be connected to each other by a common bus (170). In addition, each of the components may be connected to each other through an individual interface or individual bus centered on the processor (110), rather than the common bus (170).

The processor (110) may be implemented in various types such as an AP (Application Processor), a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), etc., and may be any semiconductor device that executes a command stored in the memory (120) or the storage device (150). The processor (110) may execute a program command stored in at least one of the memory (120) and the storage device (150). The processor (110) may store a program command for implementing at least some functions and/or operations of the receiving processing unit (720), the target direction detection unit (730), the virtual sensor setting unit (740), the virtual signal generation unit (750), and the beam forming processing unit (760) illustrated in FIG. 8 in the memory (120), and control the functions and/or operations described based on FIGS. 1 to 7 to be performed.

The memory (120) and storage device (150) may include various forms of volatile or non-volatile storage media. For example, the memory (120) may include a read-only memory (ROM) (121) and a random access memory (RAM) (122). The memory (120) may be located inside or outside the processor (110), and the memory (120) may be connected to the processor (110) through various means already known.

The input interface device (130) is configured to provide data to the processor (110).

The output interface device (140) is configured to output data from the processor (110).

The network interface device (160) can transmit or receive signals to or from an external device via a wired network or a wireless network.

At least some of the beam forming methods according to embodiments of the present disclosure may be implemented as a program or software running on a computing device, and the program or software may be stored on a computer-readable medium.

Additionally, at least some of the beam forming methods according to embodiments of the present disclosure may be implemented as hardware that can be electrically connected to a computing device.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims (10)

In a beam forming method for target detection in a beam forming device,
A step of acquiring reception signals of a plurality of first sensors arranged at a first interval for a target signal transmitted in the horizontal direction of the target,
A step of setting a plurality of virtual sensors so that the sensor spacing becomes denser than the first spacing above,
A step of compensating for the time delay of each of the plurality of first sensors in the reception signals of the plurality of first sensors to generate a time delay signal of the plurality of first sensors,
A step of generating a time delay signal of the plurality of virtual sensors through interpolation from the time delay signals of the plurality of first sensors,
A step of generating a reception signal of the plurality of virtual sensors by inversely compensating for the time delay of each of the plurality of virtual sensors to the time delay signals of the plurality of virtual sensors, and
A step of forming a beam according to detection direction from the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors.
A beam forming method comprising: In the first paragraph,
The step of generating the delay signal of the plurality of first sensors is
Comprising a step of calculating the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors for the target signal transmitted in the horizontal direction of the target.
Beam forming method. In the second paragraph,
The step of forming a beam according to the above detection direction is
A step of compensating for the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors to the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors, respectively, to generate a time delay signal of the plurality of first sensors and a time delay signal of the plurality of virtual sensors, and
A step of generating the detection direction-specific beam data from the delay signals of the plurality of first sensors and the delay signals of the plurality of virtual sensors,
Beam forming method. In the second paragraph,
The step of calculating the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors is
A step of detecting the horizontal direction of the target by forming a beam using the reception signals of the plurality of first sensors, and
Comprising a step of calculating the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors based on the horizontal direction of the target, the sensor interval, and the position of each sensor.
Beam forming method. delete In the first paragraph,
The above interpolation includes two-dimensional linear interpolation over space and time or over space and frequency.
Beam forming method. In a beam forming device for target detection,
A receiving processing unit that obtains a receiving signal received from a plurality of first sensors arranged at a first interval with respect to a target signal transmitted from a target;
A virtual sensor setting unit for setting at least one virtual sensor between each first sensor;
A virtual signal generation unit that generates time delay signals of the plurality of first sensors by compensating for the time delay of the plurality of first sensors in the reception signals of the plurality of first sensors, generates time delay signals of the plurality of virtual sensors through linear interpolation using the time delay signals of the plurality of first sensors, and generates reception signals of the plurality of virtual sensors having time delays of each of the plurality of virtual sensors by reverse compensating for the time delay of the plurality of virtual sensors in the time delay signals of the plurality of virtual sensors, and
A beam forming processing unit that generates beam data for each detection direction from the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors.
A beam forming device comprising: In Article 7,
A target direction detection unit that detects the horizontal direction of the target by forming a beam according to the detection direction from the reception signals received from the plurality of first sensors.
Including more,
The above virtual signal generation unit calculates the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors based on the horizontal direction of the target, the sensor interval, and the position of each sensor.
Beam forming device. In Article 8,
The above beam forming processing unit
Compensating for the delay time of the plurality of first sensors and the delay time of the plurality of virtual sensors for the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors, respectively, and adding the reception signals of the plurality of first sensors and the reception signals of the plurality of virtual sensors, for which the delay time has been compensated, for each detection direction to generate beam data for each detection direction.
Beam forming device. delete

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