KR101536249B1 - Method for beam performance improvemnet of virtual array antenna for detecting high speed target - Google Patents

Abstract

The present invention relates to a technology for improving beam performance of a virtual array antenna in order to improve target detection performance of a radar in case of detecting a target which moves at high speed and, more specifically, to a method for improving beam performance of a virtual array antenna for detecting a high speed target, which acquires an improved signal value per antenna beam direction with improved target detection performance, by compensating the signal value per direction of the antenna beam received by being reflected from a moving target. One aspect of the embodiment of the method for improving beam performance of the virtual array antenna for detecting a high-speed target may include: a signal calculation step of calculating a signal value per antenna beam direction from an antenna beam received by a receiving antenna; a sub-array pattern extraction step of extracting an antenna beam sub-array pattern from an in-phase antenna beam of the antenna beam; and a signal compensation step of calculating an improved signal value per antenna beam direction by compensating the signal value per antenna beam direction by the antenna beam sub-array pattern.

Description

  METHOD FOR BEAM PERFORMANCE IMPROVEMNET OF VIRTUAL ARRAY ANTENNA FOR DETECTING HIGH SPEED TARGET FIELD OF THE INVENTION [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving virtual array antenna beam performance in order to improve the target detection performance of a radar when detecting a moving target at high speed, The present invention relates to a method of improving performance of a virtual array antenna beam for high speed target detection, which compensates for a directional signal value by using a subarray pattern extracted from the antenna beam to obtain an improved signal value for each antenna beam direction.

FIG. 1 is a conceptual diagram illustrating transmission and reception of an antenna beam according to a virtual array, and FIG. 2 is a conceptual diagram illustrating transmission and reception of an antenna beam according to a target movement when the concept of a virtual array is applied. 3 shows a diagram (M = N = 8, a target moving speed (Vtar = +28, 0, -28 m / s)) showing the phase distortion characteristic of the antenna beam according to the moving speed of the target, 4 is a diagram showing the signal value (AF (θ)) of the direction of the antenna beam according to the movement speed of the target (M = N = 8, target movement speed (Vtar = +28, 0, -28 m / s Case)).

In general, radar is used to search for or track a target, and the platform and platform on which the radar is mounted determine the function and performance of the radar. In the field of automobiles, a vehicle radar is mounted to prevent collision between vehicles. In the field of defense, the radar is mounted on an unmanned platform, and various performance and functions of the radar have been developed for the purpose of autonomous navigation of the platform as well as for the purpose of searching and tracking the target to prevent collision.

Particularly, in order to achieve the high resolution performance in a radar requiring high resolution performance for target separation, the complexity of the radar hardware, especially the antenna complexity, is greatly increased. That is, in order to achieve the high resolution performance, it is necessary to increase the number of channels (number of antennas) by widening the opening surface of the antenna in consideration of the spacing between the receiving antennas. Accordingly, since the size and weight of the antenna are increased, it is difficult to mount an antenna having a high resolution performance on the platform, and the cost is increased. For example, in order to receive the antenna beam transmitted from one transmission antenna with directionality and achieve the high-resolution performance, 64 reception antennas are required. That is, the hardware complexity of the radar increases. Here, the antenna beam means a radio wave radiated from a transmission antenna and a radio wave reflected on a target and entering a reception antenna.

At this time, the signal value AF ([theta]) for each direction of the antenna beam received by the reception antenna is expressed by the following equation

[Equation 1]

. ≪ / RTI >

Here, MN is the number of reception antennas, Bi is a signal weight of MxN reception antennas, k0 is transmission / reception frequency information, drx is a distance between reception antennas, and? S is an antenna beam direction angle to be.

That is, in order to achieve a high resolution performance with respect to the antenna beam transmitted from one transmission antenna, 64 reception antennas, that is, a channel are required, and the signal value of the antenna beam on the reception antenna side AF ([theta])) can be obtained by the above-described expression (1).

Therefore, in order to achieve the high resolution performance, the concept of a virtual array as shown in FIG. 1 may be applied to solve the above problem of using a plurality of channels. That is, if the concept of the virtual array is applied, the total number of channels (the transmitting and receiving antennas) of the antenna can be reduced, thereby reducing the hardware complexity of the radar. Here, the concept of the virtual array is a concept of calculating a signal value AF ([theta]) for each direction of the antenna beam by multiplying the distance between the transmitting antennas by the product of the number of receiving antennas and the receiving antenna, Means an antenna beam transmission / reception environment in which antennas are virtually arranged so as to have an array effect by the product of the number of transmission antennas and the number of reception antennas.

Referring to FIG. 1, when M transmission antennas and N reception antennas are separated and an antenna beam is transmitted and received, the antenna beam is equivalent to transmitting and receiving antenna beams with one transmission antenna and M × N reception antennas, respectively. That is, the signal value AF ([theta]) for each direction of the same antenna beam can be obtained. However, when the virtual array concept is applied, the transmission antenna array interval dtx should be selected as a product of the receiving antenna array spacing drx and the number of receiving antennas n.

In the case of transmitting and receiving antenna beams to and from M transmit antennas and N receive antennas using the virtual array concept, the signal values AF ([theta]

&Quot; (2) "

. ≪ / RTI >

Where Am is the signal weights of the M transmit antennas and An is the signal weights of the N receive antennas. K0 is the transmission / reception frequency information, m is the mth transmission antenna position, and dtx is the distance between the transmission antennas. Also, n is the n-th receiving antenna position, drx is the receiving antenna distance,? Is the direction in which the signal is received, and? S is the antenna beam direction angle with respect to the reference plane perpendicular to the earth surface.

As described above, when the concept of the virtual array is applied, the signal value AF () of the antenna beam in the case of transmitting / receiving the antenna beam to / from one transmitting antenna and the M x N receiving antennas, The signal values AF ([theta]) for the direction when transmitting and receiving the antenna beams to the transmitting antenna and the N receiving antennas become equal.

This can be expressed as a formula,

&Quot; (3) "

Respectively.

That is, if the concept of a virtual array is applied, the total number of antenna channels is reduced from (M × N + 1) to (M + N), thereby reducing the hardware complexity, size, It is.

However, even if the target is moved according to the virtual array concept, the M transmit antennas transmit M antenna beams with a parallax, respectively, and the receive antennas receive the reflected signals from the moving target do.

Referring to FIGS. 2 and 3, when a target moves while the antenna beam is transmitted and received M times with a parallax, a phase distortion 20 between received antenna beams 3 occurs. At this time, the phase P (m, n) in the reception antenna due to the antenna beam transmission /

&Quot; (4) "

. ≪ / RTI >

Here, Vtar is the moving speed of the target, m is the transmitting antenna position, and n is the receiving antenna position. Also, M is the number of transmitting antennas, N is the number of receiving antennas, and T is the target moving time indicating the time difference. In addition, floor () means falling down to the right of the decimal point.

For example, when the number of transmission antennas 1 is eight (M = 8), the number of reception antennas 2 is eight (N = 8), and the target movement speed Vtar is +28 m / s (Vtar = +28 m / s), 0 m / s (Vtar = 0 m / s) and -28 m / s (Vtar = -28 m / s). In this case, according to the virtual array concept, a first transmission antenna (m = 1) transmits one antenna beam and eight reception antennas (N = 8) transmit the antenna beams once, 8 times. The same antenna beam is transmitted and received from the second transmission antenna to the eighth transmission antenna. Therefore, the receiving antenna receives the total of 64 antenna beams 3 and acquires 64 antenna beam receiving signal phases, respectively, as shown in FIG. 3 for three different target moving speeds Vtar.

More specifically, the phase of the received signal of the antenna beam 3 according to each target moving speed (Vtar = +28 m / s, 0 m / s, -28 m / s) (20) that the phase of the antenna beam is distorted between -17th, 24th-25th, 32th-33th, 40th-41st, 48th-49th, and 56th-57th .

Here, the first to eighth, 9th to 16th, 17th to 24th, 25th to 32th, 33th to 40th, 41st to 48th, 49th to 56th And the 57th-64th antenna beams are the same in phase. A group of antenna beam phases having the same phase in this way can be referred to as a " phase equalizer array 10 " or a " subarray 10 ".

Hereinafter, the target detection performance of the radar through the result of the signal value (100) of the direction of the antenna beam according to the moving speed of the target will be examined.

FIG. 4 is a diagram (M = N = 8, a target movement speed (Vtar = +28, 0, -28 m / s) showing a signal value 100 result of an antenna beam direction according to a movement speed of a target) to be.

Referring to FIG. 4, the side lobes 40, 50 and 60 of the antenna beam are periodically formed to be higher according to the target movement speeds (Vtar = +28 m / s, 0 m / s, -28 m / It can be confirmed that it is becoming.

However, the high side lobe 40 of the antenna beam generates a false alarm of the target detection of the radar, which causes a problem of degrading the performance of the radar. This is because a vehicle radar that detects and tracks a target in a specific direction must acquire a high antenna beam signal value 30 with respect to the specific direction 31. 4, the radar has a high decibel (dB) value within a range of 占 direction (Deg) including the specific direction width 31, i.e., the 0 direction (Deg) The signal value 30 must be obtained. If the side lobe 40 of the antenna beam is formed high, that is, if a signal value of a high antenna beam exists in the direction 41 other than the specific direction, A false alarm is generated. Therefore, the formation of the side lobe 40 of the antenna beam in the direction 41 other than the specific direction causes a problem of deteriorating the target detection performance of the radar. Here, the side lobe 40 of the antenna beam is a portion indicating a high antenna beam signal value in a direction 41 other than the specific direction, and each of the target moving speeds Vtar = +28 m / s, 0 m / s, / s). < / RTI >

Therefore, it is necessary to suppress the high side lobe 40 of the antenna beam below the required level in order to prevent the performance degradation of the radar, that is, to improve the target detection performance of the radar.

However, in the studies discussed in relation to the development of the radar for the vehicle, a technical approach is not considered to reduce the performance of the radar according to the high relative speed of the target, and the focus is on the efficiency of the hardware structure considering low cost in most cases . In addition, a multi-target technology approach is required to detect and track radar without degrading performance. Accordingly, in the present invention, a control for improving the performance of a virtual array antenna beam for high-speed target detection that maintains the target detection performance of a radar even in the case of detecting a target moving at a high speed in a radar for a vehicle to which a virtual array concept is applied Device.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned problems, and it is an object of the present invention to provide a high speed target detection virtual device for suppressing high side lobes of a receiving antenna beam to a required level or less, A method for improving array antenna beam performance is provided.

According to an aspect of the present invention, there is provided a method for improving performance of a virtual array antenna beam for high-speed target detection according to the present invention, wherein a signal value for an antenna beam direction from an antenna beam received by a receiving antenna is A signal calculation step of computing; A sub-array pattern extracting step of extracting an antenna beam sub-array pattern from an antenna beam having the same phase among the antenna beams; And a signal compensating step of compensating the signal value for each antenna beam direction by the antenna beam array pattern to calculate an improved signal value for each antenna beam direction. . ≪ / RTI >

According to the method of improving the performance of the virtual array antenna beam for high speed target detection according to the present invention, when the moving target is detected, the high side lobes of the antenna beam to be received are suppressed below the required level, and the radar frequently generates the target detection false alarm The target detection performance of the radar can be improved.

FIG. 1 is a conceptual diagram showing transmission and reception of an antenna beam according to a virtual array. FIG.
2 is a conceptual diagram illustrating transmission and reception of an antenna beam according to a target movement when the concept of a virtual array is applied.
3 is a diagram showing a phase distortion characteristic of the antenna beam according to the moving speed of the target (M = N = 8, target moving speed (Vtar = +28, 0, -28 m / s)).
4 is a diagram showing a signal value (AF (?)) Result of an antenna beam direction according to a moving speed of a target (M = N = 8, target moving speed (Vtar = +28, 0, -28 m / s ).
5 is a flowchart illustrating a method of improving the performance of a virtual array antenna beam for high-speed target detection according to the present invention.
FIG. 6 is a diagram showing a signal value (AF (?)) Performance result for each direction of an antenna single beam according to the present invention.
FIG. 7 is a diagram showing a signal value (AF (?)) Performance result for each direction of an antenna multi-beam according to the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It is noted that the technical terms used herein are used only to describe specific embodiments and are not intended to limit the invention. Also, the technical terms used herein should be interpreted in a sense that is generally understood by those skilled in the art to which the present disclosure relates, unless otherwise specifically defined in the present specification, Or shall not be construed to mean excessively reduced. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. But is to be understood as including all modifications, equivalents, and alternatives falling within the scope of the appended claims.

Hereinafter, the concept of a virtual array will be described in more detail with reference to the accompanying drawings.

3 is a diagram (M = N = 8, a target moving speed (Vtar = +28, 0, -28 m / s) showing the phase distortion characteristic of the antenna beam according to the moving speed of the target.

Referring to FIG. 3, a total of M × N reception antenna beams 3 synthesized by the virtual array concept, that is, N reception antennas, that is, 8 × 8 (total of 64 reception antenna beams) The antenna beams 3 in each of the eight sub-arrays 10 have the same phase characteristics and have different phase characteristics by the number of parallaxes (M = 8) generated in transmitting and receiving the antenna beams.

More specifically, when receiving all the M × N receive antenna beams 3 synthesized by the virtual array concept, each sub-array 10 receives 8 (N = 8) The phase of the antenna beam 3 is the same and the phase distortion 20 is generated by 8 times of transmission / reception parallax frequency (M = 8) in the entire reception antenna beams (total 64). That is, when a first transmission antenna (m = 1) transmits one antenna beam and eight reception antennas (N = 8) receive the antenna beams once, eight times in total, (3) have the same phase. When the first transmission antenna transmits one antenna beam and then one antenna beam is transmitted again from the second transmission antenna to the eighth transmission antenna so that the antenna beam is transmitted eight times in total, And receives 64 antenna beams 3. In this case, the characteristic that the phase distortion 20 is generated by the number of times 8 transmission error times (M = 8) appears.

Hereinafter, embodiments of a method for improving virtual array antenna beam performance for high-speed target detection according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 is a flowchart illustrating a method of improving the performance of a virtual array antenna beam for high-speed target detection according to the present invention, FIG. 6 is a diagram showing a result of AF (θ) , And FIG. 7 is a diagram showing the AF (θ) performance results of the antenna multi-beam according to the present invention.

The present embodiment is to improve the virtual array antenna beam performance by using the reception antenna beam 3 whose phases are equal to each other without phase distortion 20 as described above. That is, in this embodiment, among the M x N reception antenna beams synthesized by the virtual array concept, the N antenna beams 3 in the phase coherent array 10 in which the phase distortion 20 does not occur, Thereby improving the reception performance of the antenna by suppressing the side lobes 200 of the antenna beam in a direction 41 other than the specific direction to a required level or lower by forming the improvement signal value 300 for each antenna beam direction.

5, an embodiment of a virtual array antenna beam quality improvement module for high-speed target detection according to the present invention includes a signal calculation step S100, a sub-array signal extraction step S200, and a signal compensation step S300 .

The signal operation step S100 according to the antenna beam direction calculates a signal value 100 for each antenna beam direction from the antenna beam 3 received by the receiving antenna 2. [ More specifically, the signal operation step S100 derives a signal value 100 for each antenna beam direction from all the MxN reception antenna beams 3 synthesized by the virtual array concept. At this time, the antenna beam 3 may be an antenna beam 3 reflected by a target moving at high speed and received by the receiving antenna 2.

At this time, the signal value 100 for each antenna beam direction is expressed by the following equation

&Quot; (5) "

Lt; / RTI >

Here, AF (?) Is the signal value 100 for each antenna beam direction, M is the number of transmitting antennas, and N is the number of receiving antennas. In addition, Amn is a signal weight of MxN reception antenna beams, P (m, n) is a phase distortion characteristic value, and k0 is transmission / reception frequency information. M is the m th transmission antenna position, dtx is the distance between the transmitting antennas, n is the nth receiving antenna position, drx is the distance between the receiving antennas, and? S is the antenna beam directional angle with respect to the reference plane perpendicular to the earth surface .

The sub-array signal extracting step (S200) extracts the antenna beam array pattern 200 from the antenna beams having the same phase among the antenna beams (3). More specifically, the sub-array signal extracting step S200 extracts the antenna beam 3 in the sub-array 10 from all the M × N receiving antenna beams synthesized by the virtual array concept And the antenna beam array pattern 200 are generated.

At this time, the antenna beam array pattern 200 may be formed as follows:

&Quot; (6) "

Lt; / RTI >

Here, AF (?) Is the antenna beam array pattern 200, and N is the number of subarray receiving antenna beams in which no phase distortion has occurred. Where n is the position of the receiving antenna, drx is the distance between the receiving antennas, and [theta] s is the vertical distance from the surface of the earth's surface to the earth's surface, Bn is the signal weight of N subarray receiving antenna beams without phase distortion, k0 is the transmitting / Lt; RTI ID = 0.0 > reference plane. ≪ / RTI >

The signal compensating step S300 compensates the signal 100 for each antenna beam direction with the antenna beam array pattern 200 to calculate an improved signal value 300 for each antenna beam direction. More specifically, the signal combining unit 300 calculates an improved signal value 300 for each antenna beam direction by multiplying the signal value 100 for each antenna beam direction by the antenna beam unit array pattern 200 .

At this time, the improvement signal value 300 for each antenna beam direction is expressed by the following equation

&Quot; (7) "

. ≪ / RTI >

Here, AF (?) Is the improvement signal value 300 for each antenna beam direction, M is the number of transmission antennas, and N is the number of reception antennas. (M, n) is a phase distortion characteristic value, and k0 (n) is a phase distortion characteristic value of the sub-array reception antenna beams. Is the transmission / reception frequency information. M is the m th transmission antenna position, dtx is the distance between the transmitting antennas, n is the position of the receiving antenna, drx is the distance between the receiving antennas, and? S is the antenna beam direction angle with respect to the reference plane perpendicular to the ground surface.

The reason why the signal 100 for each antenna beam direction is multiplied by the antenna beam array pattern 200 is that the side lobes 40, which are generated by the phase distortion characteristic and are repeated periodically, To compensate for periodically repeated high side lobes (40).

Referring to FIG. 6, it can be understood that the side lobe of the antenna beam is lowered to a necessary level or less through the signal value 100 (300) for each antenna beam direction before and after compensation using the antenna beam array pattern 200, It can be confirmed that the reception performance is improved. The side lobe 70 of the compensated antenna beam direction-dependent signal 300 after compensation has a significantly lower height than the side lobe 40 of the pre-compensated receive antenna beam direction-dependent signal 100. Therefore, according to the after-compensation antenna beam direction improvement signal 300, since the radar may not generate a false target false alarm for the antenna beam 3 in the direction 41 other than the specific direction, The radar reception performance is remarkably improved.

The method for improving the performance of a virtual array antenna beam for high speed target detection according to the present invention can be applied not only to a radar that operates an antenna single beam but also to a radar that operates an antenna multiple beam.

Referring to FIG. 7, using M × N independent digital received signals, the antenna beam can be generated for each direction by the required number within the antenna beam coverage range. Therefore, since the antenna beam can be generated for each N phase array 10 in the corresponding direction, the antenna can detect and track a large number of targets without degrading antenna beam reception performance even for a large number of high-speed targets will be.

1: transmitting antenna
2: Receive antenna
3: antenna beam
10: Phase alignment (subarray)
20: Phase distortion
30: Antenna beam signal value for a specific direction
31: Specific direction of transmitting / receiving antenna beam
40: Vtar = + 28 m / s, the side of the reception antenna beam before compensation
41: direction other than the specific direction in which the antenna beam is transmitted and received
50: When Vtar = 0 m / s, the side of the antenna beam before compensation
60: Vtar = - 28 m / s,
70: When Vtar = +28 m / s, the compensator of the antenna beam after compensation
100: Signal by antenna beam direction (value)
200: Antenna beam section array pattern
300: Improved signal (value) by antenna beam direction

Claims (4)

A method for improving virtual array antenna beam performance for high speed target detection,
A signal calculating step of calculating a signal value for each antenna beam direction from the antenna beam received by the receiving antenna;
A sub-array pattern extracting step of extracting an antenna beam sub-array pattern from an antenna beam having the same phase among the antenna beams; And
Compensating the signal value for each antenna beam direction by the antenna beam array pattern to calculate an improved signal value for each antenna beam direction,
The signal values according to the antenna beam directions are expressed as follows:

(M, n) is a phase-distortion characteristic value, k0 is transmission / reception frequency information, and A (m, n) m is the m th transmission antenna position, dtx is the distance between the transmitting antennas, n is the nth receiving antenna position, drx is the distance between the receiving antennas,? is the direction in which the signal is received,? s is the reference plane perpendicular to the earth surface Wherein the antenna beam direction angle is calculated by the antenna beam direction angle of the antenna array.
delete The method according to claim 1,
In the subarray pattern extracting step,
The antenna beam unit array pattern includes:

Where n0 is the n-th receiving antenna position, drx is the distance between the receiving antennas, and n is the receiving antenna position, and? s is an antenna beam directional angle with respect to a reference plane perpendicular to the ground surface).
The method according to claim 1,
In the signal compensation step,
The improved signal values for the antenna beam directions are:

M is the number of transmit antennas, N is the number of receive antennas, Amn is the signal weights of MxN receive antenna beams, (M, n) is a phase distortion characteristic value, k0 is transmission / reception frequency information, m is an m-th transmission antenna position, dtx Is a distance between the transmitting antennas, n is a position of the receiving antenna, drx is a distance between receiving antennas, and? S is an antenna beam directional angle with respect to a reference plane perpendicular to the ground surface) Method for improving array antenna beam performance.

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