KR20150076755A - Method for arranging array plane of phase array antenna and method for operating the same - Google Patents

Abstract

The present invention relates to a method for arranging an array plane of phase array radar. The method for arranging an array plane of phase array radar corrects for an array plane to have identical phase and gain. According to an embodiment of the present invention, the method includes: an inner signal source correcting step of authorizing a correction signal preset in each unit antenna of phase array radar, correcting a difference in authorized paths of signals received in each of the unit antennas, and calculating a first correction value per unit antenna; a far-field beacon correcting step of performing reception for each unit antenna through far-field beacon measurement and calculating a second correction value which makes the phase and the gain identical with the preset reference phase and reference gain respectively per unit antenna; and a phase and gain correcting step of correcting the phase and the gain for the signals received and transmitted in the phase array radar by applying the first correction value and the second correction value per unit antenna.

Description

[0001] The present invention relates to a method of arranging a phase array radar,

The present invention relates to a method of aligning phased array radars, and more particularly, to a method of aligning phased array radars in which phased array radars have the same phase and gain.

Efficient signal processing in the active model and thus the performance of the system becomes possible on a stable hardware basis. Currently, this model is being developed as a state-of-the-art spatio-temporal processing technology by combining an array antenna and a baseband signal processor. The active phased array radar hardware is required to have high reliability of each component that is based on the heat radiation structure of the system which is more stable than in the past.

In the internal functions and processing structures, various forms are being developed according to the purpose. Since a relatively small number of transmission / reception channel processing requires a large number of multi-channel processing, various forms are being developed, / Receiving channel processing, a multitude of multi-channel processing is required. Therefore, it is a technical issue to correct misalignment by correcting the gain and phase between channels in a near field or a far field system.

The correction and analysis method in the planar array antenna structure can be repeatedly performed by interpreting and correcting it in the near field environment, which is a laboratory environment, using the antenna 10 and the probe 20 as shown in FIG. 1, There is a method of correcting the code by comparing the code of each channel using the built-in phase code in the original electric field environment as shown in FIG.

However, in the case of the correction through the near field measurement in FIG. 1, the condition is relatively good, in which the external environmental factors are excluded and the characteristic test of the pure antenna and the transceiver is performed. However, It is exposed to the external environment and surrounding noise components, and correction is not made correctly. If the correction is not performed correctly, if the measured correction value is used externally, the performance of the whole system may be deteriorated. In this case, it is necessary to perform re-measurement in the internal chamber environment again for the precise correction thereof, so that it is subjected to a lot of time and space restrictions. Also, in the case of equipment or systems that are actually deployed and operated, they will not be able to perform system-specific tasks in their area or area during the recalibration process. Also, in the case of a communication system using a phased array radar or an array antenna, there are several thousand or more reception channels independently, and there arises a problem that considerable difficulties arise in performing correction for multiple channels.

In the case of correction through the measurement of the source electric field, it is possible to extract independent phase and gain for each channel by using an orthogonal code for each channel as shown in FIG. 2. If the number of channels is large, generation of orthogonal codes of each channel is essential As the length of the orthogonal code increases, due to the complexity of the side lobes and the implementation algorithm for the orthogonal codes of many channels, the matched filter is limited in the overall function and performance due to the calculation required for the correction value extraction and the repeatability thereof. Condition occurs. This is because it is necessary to finally extract the phase and gain of the dither channel and to perform measurement by activating all the channels, so that it becomes difficult to perform the correction function when checking a specific channel or individual channel. Even if the function for the individual channel is added, the overall transmission / reception gain is reduced, and there is a disadvantage that the additional transmission power and the receiver gain according to the distance must be increased.

Korean Patent Publication No. 10-2005-0055540

The technical problem of the present invention is to improve the correction through the measurement of the near field and the correction through the measurement of the electric field. Another object of the present invention is to provide a correction method for increasing the accuracy of correction for each channel. The present invention also provides a method of easily correcting a phased array radar even if the field environment changes after the phased array radar is installed in a field site.

An embodiment of the present invention is a radio communication method in which a predetermined correction signal is applied to each unit antenna of a phased array radar to correct a difference in an applied path of a signal received by each unit antenna, Circle correction process; A unit for calculating a second correction value for each unit antenna by performing reception of each unit antenna by measuring the electric field beacon so that the phase and gain of each unit antenna become equal to a predetermined reference phase and a reference gain, A beacon correction process; And a phase and gain correcting step of correcting phase and gain of a signal transmitted and received by the phased array radar by applying a first correction value and a second correction value together for each unit antenna.

And performing correction of the phase and gain of each unit antenna by performing only the internal signal source correction when the radio field environment of the region where the phased array radar is installed is changed after the phase and gain correction process is performed, In addition, it has more.

The internal signal source correcting process includes: a correction signal applying step of applying a predetermined correction signal to each unit antenna of the phased array radar; Extracting a phase and a gain of a reception signal received at each unit antenna; And calculating a first correction value for each unit antenna such that the phase and gain extracted from the received signal are equal to the phase and gain of the correction signal.

The process of applying the correction signal includes: storing a correction signal having a correction phase and a correction gain in a correction signal memory; Extracting a correction signal stored in the correction signal memory; And applying the same correction signal to each unit antenna.

Calculating the first correction value for each unit antenna; Extracting a phase and a gain of a received signal for each unit antenna as a reception phase and a reception gain, respectively; A correction phase difference value which is a difference between a reception phase in each unit antenna and a correction phase of a correction signal stored in the correction signal memory and a correction gain difference between a reception gain in each unit antenna and a correction gain of the correction signal stored in the correction signal memory Calculating a correction gain difference value for each unit antenna; And calculating a correction phase difference value and a correction gain difference value calculated for each unit antenna as a first correction value.

Wherein the step of correcting the at least one of the at least two beacons comprises the steps of: A source-field phase and gain extraction process for extracting a phase and a gain of each unit antenna; And calculating a second correction value for each unit antenna so that the phase and gain of the extracted unit antenna become equal to a preset reference phase and a reference gain.

When performing transmission and reception for each unit antenna using a beacon of a source electric field, only a unit antenna for extracting a phase and a gain is activated and the other unit antennas are deactivated.

The phase and gain extraction process of the electric field system is characterized in that digital pulse compression is performed on the received signal to extract the phase and gain after removing the noise.

According to the embodiment of the present invention, the correction accuracy can be improved by considering the difference in the path of the applied signal and the characteristic of the original electric field. Also, even if the field environment changes after the phased array radar is installed in the field, the phase and gain can be corrected simply by performing the correction using the internal signal source.

FIG. 1 is a diagram illustrating a method of correcting in a near-field environment.
FIG. 2 is a diagram showing a method of correcting in a circular electric field environment. FIG.
3 is a flow chart illustrating a process of aligning a phased array radar according to an embodiment of the present invention.
FIG. 4 is a view showing an arrangement surface in which one or more unit antennas are arranged.
5 is a diagram showing a state in which a correction signal is applied according to a signal of the present invention to calculate a phase and a gain and to calculate a first correction value.
6A is an experimental graph showing that the phase distributions of the reception signals of the unit antennas are not coincident with each other due to differences in the application paths of the correction signals.
6 (b) is an experimental graph in which the phase distribution of the reception signal of each unit antenna is matched with the correction signal as the same signal.
FIG. 7A is a diagram illustrating a measurement of a propagation path for each unit antenna (each channel), and a correction value for each channel is stored in a nonvolatile memory.
7 (b) is a diagram showing the same specific value (correction signal) determined by the user without having to measure the propagation path for each channel according to the embodiment of the present invention.
FIG. 8 is an experimental photograph showing a state in which alignment is not performed when the correction according to the first correction value is performed according to the embodiment of the present invention.
FIG. 9 is a diagram illustrating a beacon and a radar for correction of a source electric field beacon according to an embodiment of the present invention.
FIG. 10 is a graph showing the reception signal results for each channel using the electric field beacon when pulse compression is not performed.
FIG. 11 is a graph showing the result of a received signal for each channel using a pulse-field beacon when pulse compression is performed according to an embodiment of the present invention.
FIG. 12 is a photograph showing a two-dimensional digital beam pattern in which the phase and gain distributions of the antenna surface are uniformly corrected by the method of the present invention.
FIG. 13 is a photograph showing SNR performance of target information obtained by activating all channels before and after performing a source-field correction when the array alignment is performed in a circular electric field environment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

In the following description, an example of correcting the received signal of the phased array radar will be described, but the same can be applied to correcting to be correctly transmitted in the phased array radar.

3 is a flow chart illustrating a process of aligning a phased array radar according to an embodiment of the present invention.

In the embodiment of the present invention, a predetermined correction signal is applied to each unit antenna of the phased array radar to correct the difference in the application paths of the signals received by the respective unit antennas, and an internal signal And a second correction value for making the phase and gain equal to a predetermined reference phase and a reference gain for each unit antenna by performing a circular correction process (S310) (S320) for calculating a first correction value and a second correction value for each of the unit antennas, and corrects phase and gain of a signal transmitted and received in the phase- And a gain correction process (S330). If the radio field environment of the region where the phased array radar is installed changes after the phase and gain correction process, only the internal signal source correction is performed without correcting the source electric field beacon to correct the phase and gain for each unit antenna at step S340. Therefore, in the case of the phased array radar corrected by the first correction value and the second correction value, when the field environment is changed during field use and needs to be corrected, only the correction through the internal signal source is performed without correcting the electric field beacon, It is possible to perform a simple and quick correction.

In detail, in the step S310, a correction signal for applying a predetermined correction signal to each unit antenna of the phased array radar is applied (S311).

The phased array radar is an antenna in which one or more unit antennas Amn are arranged as shown in FIG. 4, and each unit antenna forms each radio channel. As shown in FIG. 4, m × n unit antennas are arranged in the case of the mn array antenna.

The arrangement of the phased array radars, that is, the planes on which the plurality of unit antennas are arranged, must be in phase with each other. . However, by adjusting the phase of each unit antenna, it is possible to adjust the radiation pattern in the desired direction, not the 90 ° direction of the arrangement plane.

Therefore, the array plane of the phased array radar must have the same phase. To make the array plane of the phased array radar in phase, a correction signal for applying a predetermined correction signal to each unit antenna of the phased array radar is applied Process.

And applies a correction signal referenced to each unit antenna of the phased array radar as shown in FIG. Such a correction signal utilizes a correction signal stored in a memory (hereinafter referred to as a 'correction signal memory'). Therefore, the correction signal application process of applying the same correction signal to each unit antenna of the phased array radar is performed by storing a correction signal having a certain phase (hereinafter referred to as' correction phase ') and gain (hereinafter referred to as' correction gain) Extracting a correction signal stored in the correction signal memory, and applying a correction signal extracted for each unit antenna in the same manner.

At this time, when a correction signal is applied to each unit antenna, the phase and gain of the signal received by each unit antenna may vary according to the application path of the correction signal, as shown in FIG. Therefore, it is necessary to calculate a first correction value that matches this with the correction signal.

For this purpose, the phase and gain of the received signal are extracted from each unit antenna. And a first correction value calculation step of generating a first correction value for each unit antenna so that the phase and gain extracted from the received signal are equal to the phase and gain of the correction signal. Here, the first correction value is used to correct a difference generated due to a different application path of the correction signal for each channel (unit antenna).

For example, referring to FIG. 6A, it can be seen that the phase distributions of the reception signals of the unit antennas do not coincide with each other due to the difference in the application paths of the correction signals. The first correction value for matching the phase distribution of the reception signals of the unit antennas that do not coincide with each other as the same signal as the correction signal is calculated as shown in Fig. 6 (b).

As shown in FIG. 7 (a), the transmission path is measured for each unit antenna (each channel) in order to correct the correction signal, and the correction value for each unit antenna is stored in the nonvolatile memory. However, according to the embodiment of the present invention, it is not necessary to measure the propagation path for each channel as shown in FIG. 7 (b), and all channel states are transited so as to coincide with the same specific value (correction signal) .

Meanwhile, the phase and gain of the reception signal received for each unit antenna are respectively extracted as the reception phase and the reception gain (S312). For reference, there are various methods for extracting the gain and phase on the channel. In the embodiment of the present invention, the phase and gain relation for complex data on a channel is given by the following general formula [1].

[Equation 1]

Where I is the real number of the channel complex value and Q is the imaginary number. Also,? Is a gain value on the transmission / reception path and is a variable value that varies depending on the application system to be designed.

On the other hand, after the phase and gain of the reception signal received for each unit antenna are extracted as the reception phase and the reception gain (S312), the reception phase of each unit antenna and the correction phase of the correction signal stored in the guarantee signal memory And a correction gain difference value which is a difference between the correction gain of the correction signal stored in the correction signal memory and the reception gain of each unit antenna is calculated for each unit antenna. Then, the correction phase difference value and the correction gain difference value calculated for each unit antenna are calculated as the first correction value (S313). When the first correction value of each unit antenna is added to the phase of each unit antenna shown in FIG. 6 (a), as shown in FIG. 6 (b), a signal having one phase and gain Lt; / RTI >

On the other hand, even if the first correction value is calculated and corrected as described above, it means only a state in which all channels are transited to an arbitrary state selected by the user. As shown in Fig. 8, the actual arrangement surface state is not in a state in which alignment is performed. Therefore, a correction is required to make the phase and gain of the array surface of the phased array radar equal.

For this purpose, the reception of each unit antenna is performed by measuring the electric field beacon, and a second correction value is calculated for each unit antenna so that the phase and gain are equal to the reference phase and the reference gain set in advance for each unit antenna And a source electric field beacon correction process (S320).

The source electric field beacon correction (S320) includes a process (S321) of performing transmission and reception for each unit antenna using a beacon of a source electric field. The beacon is a device for transmitting a radio wave toward the phased array radar as shown in Fig. The phased array radar should be located within a certain distance from the beacon to receive plane waves so that plane waves can be received on the array side of the phased array radar. Beacons must meet the following conditions: That is, the signal provided from the beacon receives and uses the transmission signal of the external main apparatus, and the beacon signal delays the transmission signal of the main equipment from the distance information known by the user. When transmitting and receiving for each unit antenna by using the beacon of the source electric field, only the unit antenna for extracting phase and gain is activated and the other unit antenna is inactivated.

And a step (S322) of extracting the phase and gain of each unit antenna from the signal received using the beacon of the source electric field. The extraction of phase and gain of each unit antenna (S322) extracts the phase and gain result value of each channel received from the beacon by applying the digital pulse compression technique. Digital pulse compression is performed on the received signal to remove the noise and extract the phase and gain. In the absence of digital pulse compression techniques, the received signal is indistinguishable from the noise level due to the low gain of each channel. That is, as shown in Fig. 10, the noise level is not distinguished from the noise level due to the low gain. In FIG. 10, the horizontal axis represents the time axis, the vertical axis represents the size, and red and blue represent I (Inphase) and Q (Quadrature), respectively, for each channel.

When the digital pulse compression technique is applied to the phase and gain result values of each channel, it can be seen that a peak point is generated at a specific distance as shown in FIG. 11 due to the SNR improvement. Similarly, in FIG. 11, the horizontal axis represents the time axis, the vertical axis represents the size, and red and blue represent I (Inphase) and Q (Quadrature), respectively, for each channel.

The digital pulse compression technique used to extract the phase and gain result values of each channel received from the beacon applies a conventionally known equation for performing pulse compression. Hereinafter, digital pulse compression will be briefly described.

In order to apply the correction method using the digital pulse compression in the source electric field environment, the following condition of [Equation 1] must be satisfied.

[Equation 1]

Where R is the source distance condition, D is the antenna size, and λ is the wavelength of the operating frequency in the beacon.

The condition of the plane wave is satisfied unlike the proximity electric field when the condition of the above-mentioned [Equation 1] is satisfied, and the phase and gain information of each channel becomes a condition of high reliability. Digital pulse compression is usually used to increase the distance resolution in the radar. The modulation waveform is accompanied by the transmission of relatively wide pulses, which also accompanies an improvement in the signal-to-noise ratio (SNR) of the receiver during digital demodulation. In the present invention, the digital pulse compression is used not to increase the distance resolution but to increase the SNR of the signal. [Equation 2] shows a typical radar equation.

[Equation 2]

L is the distance, R is the distance, P is the transmit power, G is the transmit and receive antenna gain, lambda is the wavelength of the operating frequency, and σ is the radius of the radar, where k is Boltzmann's constant, T is the Kelvin constant, And a reflection area (RCS).

The signal to noise ratio (SNR) performance depends on various factors such as the equation. Here, the bandwidth existing in the shunt component is considered. The bandwidth is related to the pulse width of the modulated waveform on the time axis. Therefore, it is possible to obtain an effect of increasing the overall SNR by driving a wide transmission pulse. This allows the weak received signal of the individual channel to be amplified at the noise level level with relatively distance. In the present invention, the I / Q (Inphase / Quadrature) component for each channel is extracted through digital pulse compression of a very small received signal provided through a beacon, and then phase and gain information for each channel is extracted. The advantage of this method is that there is no need for a high transmit power of the beacon to extract the phase and gain information of the individual channels, and there are two advantages that can improve the gain of the relatively low receiver. [Equation 3] is a general digital pulse compression performed in the frequency domain.

[Equation 3]

Here, N ₁ is a sequence of x ₁ (n), and N ₂ is a sequence of x ₂ (n).

As can be seen from Equation (3), the product of the two signal sequences in the frequency domain has a convolution effect on the two signals on the time axis. In the present invention, since it is a method of applying the previously established theory of [Equation 3] rather than the content of [Equation 3], a description thereof will be omitted.

On the other hand, after extracting the phase and gain of each unit antenna through digital pulse compression, a second correction value is calculated for each unit antenna so that the phase and gain of the extracted unit antenna become equal to the reference phase and the reference gain set in advance (S323). And calculates a second correction value for each unit antenna so that the phase and the gain of each channel become equal to a preset value.

Thereafter, the first correction value and the second correction value are applied to each unit antenna, and the phase and gain are corrected for signals transmitted and received in the phased array radar (S330). For example, a first phase can be obtained from the first unit antenna, and the first and second correction values of the first unit antenna are applied to the first phase to correct the first phase. Similarly, a second phase can be obtained in the second unit antenna, and the first and second correction values of the second unit antenna are applied to the second phase to correct the second phase.

Correct transmission and reception can be performed by applying a first correction value for correcting a signal application path and a second correction value for correcting in a source electric field to a signal transmitted and received in the phased array radar and correcting and outputting the same.

Meanwhile, if the radio field environment of the region where the phased array radar is installed changes after the phase and gain correction process, only the internal signal source correction is performed to correct the phase and gain for each unit antenna with the first correction value (S340).

In the case of the phased array radar installed in the field after the correction for the phase and the gain is performed through the first correction value and the second correction value, the radio field environment changes due to the temperature change, the change of the local environment, . Such changes in the propagation field environment can lead to errors in the phase and gain of the corrected phased array radar.

If an error is generated due to the change of the field environment (S341), only the internal signal source correction for correcting the generated error by the first correction value is performed (S342). The reason for correcting the internal signal source after field installation is as follows.

In the present invention, the phase and gain of each channel are first adjusted to one reference value using an internal signal correction source in an actual field environment, then information of each channel using digital pulse compression is extracted, You must. When the correction is performed through such a procedure, the method using the beacon under the electric field condition is advantageous in that the entire array surface can be maintained in a stable state even if it is performed only once. This means that it is not necessary to individually refer to the individual correction data of each channel through the conventional electric field system in the memory such as the memory in order to arrange the state of each channel individually in the memory. When the calibration is performed through this procedure, when the actual equipment is operated, only the internal signal source is used, and if the phase and gain values per channel are adjusted to one value desired by the user, the stable state of the entire array surface is maintained .

Meanwhile, as can be seen from the results of FIG. 12, it can be confirmed by the two-dimensional digital beam pattern that the phase and gain distributions of the antenna surface are uniformly corrected by the method of the present invention. Basically, when the array alignment is performed in the source electric field environment, the SNR performance of the target information obtained by activating all the channels as shown in FIG. 13 is significantly improved as compared with the result before the source electric field correction 20dB improvement effect). In addition, the entire array alignment is performed by using the signal source such as an internal signal source and an external beacon once, respectively, to perform precise correction. Thereafter, only the internal signal source is used to perform a necessary or periodic correction operation, Stability can be guaranteed.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

S310: Internal signal source correction process S320: Beacon correction process
S330: Phase and gain correction process

Claims (8)

An internal signal source correcting step of applying a predetermined correction signal to each of the unit antennas of the phased array radar to correct the difference in the application paths of the signals received by the respective unit antennas to calculate a first correction value for each unit antenna;
A unit for calculating a second correction value for each unit antenna by performing reception of each unit antenna by measuring the electric field beacon so that the phase and gain of each unit antenna become equal to a predetermined reference phase and a reference gain, A beacon correction process;
A phase and gain correction process of applying a first correction value and a second correction value to each of the unit antennas to correct phase and gain of a signal transmitted and received in the phased array radar;
Wherein the phase array radar comprises a plurality of phased array radars.
2. The method of claim 1, wherein, after the phase and gain correction process, if the radio field environment of the region in which the phased array radar is installed is changed, only the internal signal source correction is performed, Wherein the step of adjusting the alignment of the phased array radar further comprises the further step of calibrating the phased array radar.
2. The method of claim 1,
A correction signal applying step of applying a predetermined correction signal to each unit antenna of the phased array radar;
Extracting a phase and a gain of a reception signal received by each unit antenna;
Calculating a first correction value for each unit antenna such that the phase and gain extracted from the received signal are equal to the phase and gain of the correction signal;
Wherein the phase array radar comprises a plurality of phased array radars.
4. The method of claim 3,
Storing a correction signal having a correction phase and a correction gain in a correction signal memory;
Extracting a correction signal stored in the correction signal memory;
Applying the same correction signal to each unit antenna;
Wherein the phase array radar comprises a plurality of phased array radars.
The method of claim 3, further comprising: calculating the first correction value for each unit antenna;
Extracting a phase and a gain of a received signal for each unit antenna as a reception phase and a reception gain, respectively;
A correction phase difference value which is a difference between a reception phase in each unit antenna and a correction phase of a correction signal stored in the correction signal memory and a correction gain difference between a reception gain in each unit antenna and a correction gain of the correction signal stored in the correction signal memory Calculating a correction gain difference value for each unit antenna;
Calculating a correction phase difference value and a correction gain difference value calculated for each unit antenna as a first correction value;
Wherein the phase array radar comprises a plurality of phased array radars.
2. The method of claim 1,
Performing reception for each unit antenna using a beacon of a source electric field;
A source-field phase and gain extraction process for extracting a phase and a gain of each unit antenna;
Calculating a second correction value for each unit antenna so that the phase and gain of the extracted unit antenna become equal to a reference phase and a reference gain set in advance;
Wherein the phase array radar comprises a plurality of phased array radars.
The phase-aligned radar array array according to claim 6, wherein when transmitting and receiving are performed for each unit antenna using the beacon of the source electric field, only the unit antenna for extracting the phase and the gain is activated and the other unit antennas are deactivated Way.
7. The method of claim 6,
And performing digital pulse compression on the received signal to remove noise and extract phase and gain.

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