KR101164093B1 - A simulation system and method for instrumentation radar tracking an antenna signal from the target - Google Patents

Abstract

The present invention relates to a measurement radar target antenna signal tracking simulator and a method thereof, and to model the target by the results of the full-wave target antenna electromagnetic field analysis and the expected flight trajectory and attitude change, and the transmission and reception characteristics of the radar and Instrumentation radar modeling with servo loops can be used to determine the gain of the target antenna and to predict the signal-to-noise ratio over distance. In addition, it is possible to set the expected track failure risk interval during flight test by identifying the section where the tracking error increases such as multipath interference by simulating the measurement radar tracking status.

Description

Instrumentation radar simulation apparatus and method for tracking the target antenna signal {A SIMULATION SYSTEM AND METHOD FOR INSTRUMENTATION RADAR TRACKING AN ANTENNA SIGNAL FROM THE TARGET}

The present invention relates to a tracking state of a measurement radar and a method of operating a measurement system for successful test measurement through a measurement radar tracking state simulation before flight test.

In the existing radar simulator, it is difficult to use the variables according to flight trajectory and attitude change that can be additionally obtained by representing the radar reflection characteristics of the target target as a constant or statistically represented Swerling model. This provides only theoretical results for the actual flight test environment and thus cannot explain the abnormal conditions of the various signals generated in the actual flight test and is insufficient to apply to test measurement planning.

During the test evaluation phase of the precision hit weapon system operating in the future battlefield, flight test has high level measurement requirements such as multi-target tracking, so the pre-test measurement radar tracking status is predicted for successful test measurement by simulating the test radar tracking status before the test. Verification of the operation of the system and measurement system is required. The measurement radar tracking simulation technology uses the measurement system, digital terrain information DB, and target information to obtain simulation results based on three-dimensional visualization, and applies it to advanced test centers as a task plan for measuring equipment.

Modeling of the tracking system is carried out to detail. Modeling of the target applies simple posture and electromagnetic target modeling for the low frequency band, and the simulation results of the electromagnetic analysis in the actual radar frequency band are applied to the model. It is judged that it is not applied. In addition, the tracking error analysis of the measurement radar considering the environmental factors of the test site is used for the analysis of each case, and it is judged that the application of the integrated tracking simulation technology considering all these factors has not yet been reached.

In order to solve the above problems, the present invention intends to establish an efficient measurement plan by setting a tracking risk interval of a measurement system through simulation of a target antenna signal of a measurement radar before performing a flight test performed at a test site and a space center. have.

The present invention provides a simulation method for tracking a target antenna signal in a measurement radar, the method comprising: modeling a target by using an electromagnetic field analysis of a target antenna, predicted trajectory of a target, and attitude change data; Modeling the measurement radar in consideration of the transmission / reception characteristics of the radar and the driving of the servo loop; And driving a tracking algorithm to check the tracking error of the radar and determine the measurement risk.

In addition, the step of modeling the target is characterized in that it has an electric field characteristic obtained in a full-wave (full-wave) method.

The electromagnetic field analysis of the target antenna may include selecting a target and an antenna model mounted on the target; Independently performing simulations on the antennas to obtain results for electric field analysis and antenna characteristics for the selected antennas; Comparing the radiation pattern measurement of the actual antenna with the performed simulation value; Preparing a simulation shape for a target and converting it into a model for electromagnetic analysis when the antenna is mounted; Setting a position and number of target antennas; And mounting the antenna model to a target model to perform an electromagnetic analysis on the target antenna.

In addition, the step of modeling the target is characterized in that for applying the rotation matrix for the change of the posture of the roll, pitch, yaw to the position of the target with respect to time.

The servo loop may be modeled using a PI controller.

In addition, a simulation system for tracking a target antenna signal in a measurement radar, the simulation system comprising: a target modeling unit for modeling a target using electromagnetic field analysis, target trajectory, and posture change prediction data of the target antenna; A measurement radar simulator for performing modeling on the measurement radar in consideration of transmission and reception characteristics of the radar and driving of the servo loop; And an algorithm driver for driving the tracking algorithm to check the radar tracking error and determine the measurement risk.

In addition, the algorithm driving unit calculates the electromagnetic wave characteristics of the target according to the expected trajectory and movement of the target and a specific variable according to the antenna selection, and calculates and applies an error according to the servo characteristic of the radar to the calculated value. It features.

The target antenna tracking simulator and method of the measurement radar according to the present invention has the capability of predicting the tracking state of the measurement equipment and determining the danger zone in the flight test, which has not been proposed in the past, and suggests the optimal measurement performance of the measurement radar. It works.

1 is a diagram illustrating a simulation method for tracking a target antenna signal of a measurement radar according to the present invention.
2A is a flow chart for performing electromagnetic field analysis in a full-wave manner of a target antenna.
FIG. 2B illustrates a procedure for performing electromagnetic analysis in a full-wave manner of a target antenna. FIG.
3 is a diagram showing an electromagnetic field analysis result of a beam radiation pattern for the antenna itself obtained through target modeling.
4 is a view showing a beam radiation pattern analysis results for the target antenna having a guided weapon system shape.
FIG. 5 is a diagram illustrating roll, pitch, and yaw of an expected flight trajectory of the target and a change in attitude of the target over time as an embodiment of the present invention. FIG. 6 illustrates the azimuth angle (), elevation angle () for determining antenna gain from the radar direction vector of the target antenna.
7 is a view showing a change in azimuth and elevation with respect to time using [Equation 4].
Fig. 8 is a diagram showing the change in the signal-to-noise ratio of the measurement radar with respect to the obtained distance as a result of the measurement radar tracking state simulation.
FIG. 9 is a diagram illustrating a tracking risk section of a measurement radar based on the result of FIG. 8; FIG.
10 illustrates a simulation system for tracking a target antenna signal of a metrology radar in accordance with the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of related well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

Hereinafter, a method of estimating the measurement state by simulating the tracking state of the measurement radar using the beam radiation pattern result of the target antenna signal through the electromagnetic field analysis and calculation will be described.

First, FIG. 1 is a diagram illustrating a simulation method for tracking a target antenna signal of a measurement radar according to the present invention.

First, the target is modeled using the electromagnetic field analysis of the target antenna, the predicted trajectory or the attitude change data of the target antenna. (S-11) Here, the target formation process is performed by the electric field characteristics obtained by the full-wave method. Has

In addition, the electromagnetic field analysis of the target antenna is measured by putting the actual antenna in the omni-directional chamber for comparison with the antenna pattern measured for the antenna designed or introduced in the actual shape. After modeling using the same ground plane as the jig used above, the results are compared with each other.

Once the design and analysis of the antenna has been completed, the CAD data is produced by editing the approximated model or the actual shape.

An antenna designed on the CAD fixture is mounted to perform electromagnetic field analysis according to conditions. A process of performing the electromagnetic field analysis will be described with reference to FIG. 2. In addition, a detailed process of modeling the target using the predicted trajectory or posture change prediction data of the target will be described with reference to FIGS. 5 to 8.

Next, the measurement radar is modeled in consideration of the mono pulse characteristic (radar transmit / receive characteristic) and the servo loop driving which are the tracking characteristics of the radar.

The servo loop for driving the antenna pedestal can be modeled with a simple PI controller. Here, the input to the servo loop models the monopulse tracking of the measurement radar to become an error signal in an elevation direction in a multipath interference situation.

Next, the tracking algorithm is driven to check the radar tracking error and determine the measurement risk. (S-13)

In the driving of the tracking algorithm, the electromagnetic wave characteristics of the target according to the expected trajectory and the movement of the target and a specific variable according to the antenna selection are performed. After that, an error according to the servo characteristic of the radar is calculated and applied to the calculated value. Therefore, through this, the tracking error of the radar can be finally confirmed, and the radar measurement risk is finally determined by adding a state determination method to determine the measurement risk accordingly.

2 is a flowchart of performing electromagnetic field analysis on a full-wave method of a target antenna.

First, the target and antenna model for the electromagnetic field analysis of the target antenna is selected. It refers to the shape using CAD (Computer Aided Design). The shape structure of the part with little influence on the electromagnetic analysis is simplified and applied. In addition, the target and antenna models are selected depending on whether the test is actually performed.

Next, an independent simulation is performed on the antennas mounted on the aviation weapon system and the guided weapon system. (S-22) That is, a simulation process on the antenna is performed. Here, the results of the electric field analysis and antenna characteristics are obtained using the MoM (Finite Element Method), FEM (Finite Differential Time Domain), and the like, which are electromagnetic analysis methods. You can write your own calculation code to implement it, or you can get the results with commercially available electromagnetic analysis tools such as CST, FEKO, and HFSS.

The simulation is performed to obtain the measured radar tracking state in the environment similar to the actual flight test by considering the field modeling value, the attitude and trajectory tracking information of the target, and the environment modeling value.

Next, the radiation pattern measurement value of the actual antenna is compared with the value of the simulation. (S-23) To verify the electromagnetic analysis result of the antenna, the radiation pattern of the actual antenna is measured and the results are compared. Comparison with the measured values verifies the modeling results of the antenna geometry and the simulation results of the electromagnetic analysis.

According to the comparison result, if necessary, the process of matching the shape of the antenna model to the actual shape is repeatedly performed.

      Next, a process of manufacturing and converting the shape of the target such as the guided weapon system is performed. (S-24)

This is a stage of converting or designing a model for simulating electromagnetic analysis when an antenna is mounted using drawings of a target weapon system or pre-implemented CAD data. However, in general, information on the actual shape of the weapon system is often not disclosed. In this case, the size and position of the weapon system are determined based on a photograph or similar published shape, and the target model for the weapon system is CAD. It is shown using.

Next, the position and the number of target antennas are set. (S-25)

The location and number of target antennas are determined by the location and available space of the actual communication system provided by the developer. In addition, it may be used as a method of obtaining an optimized antenna position and number by performing simulation in consideration of the actual available position or number.

Finally, after mounting the antenna model on the target, a simulation is performed on the target antenna. (S-26)

The verified antenna model is mounted on the target model to perform an electromagnetic analysis on the target antenna. At this time, if it is determined that the position and number of target antennas set in the previous step are not optimized due to poor directivity in a specific direction, the target antenna simulation is performed again by adjusting again.

As shown in FIG. 2, after the antenna simulation of the target is finished, the target shape is simplified and the antenna value of the simulation is input to the position of the antenna used for the target. And after reviewing the optimal algorithm for analysis and performing analysis time for the required time, analyze the analysis result.

3 shows an electromagnetic field analysis result of the beam radiation pattern for the antenna itself obtained through the target modeling, Figure 4 shows a beam radiation pattern analysis result for the target antenna having the shape of the guided weapon system.

), 고각(

)을 정의한 도이다.
FIG. 5 is a diagram showing a roll, pitch, and yaw of an expected flight trajectory of the target and a change in attitude of the target over time according to an embodiment of the present invention. 6 also shows an azimuth angle for determining the antenna gain from the radar direction vector of the target antenna.

), Elevation (

) Is defined.

5 and 6, a method of modeling a target using predicted trajectory or posture change prediction data of the target will be described.

First, the position of the target with respect to time can be expressed as a point (E (t), N (t), U (t)) on the reference ENU (East, North, Up) Cartesian coordinate system. In the case of a change in the attitude of the target, the X, Y, and Z axes do not exactly point to East, North, and Up at a point on the ENU Cartesian coordinate system. In this case, the rotation matrix R _YPR for the roll, pitch, and yaw attitude changes should be taken into account.

The rotation matrix R _YPR may be calculated by using Equations 1 and 2 below.

는 하기 수학식 3을 이용하여 계산할 수 있다.Also, the direction vector of the measurement radar

Can be calculated using Equation 3 below.

로부터 도 6에 도시된 바와 같이, 방위각(

) 및 고각(

)은 하기 수학식 4를 이용하여 계산할 수 있으며, 시간에 대한 함수가 된다.Also, the measurement radar direction vector

6, the azimuth angle (

) And elevation (

) Can be calculated using Equation 4 below, which is a function of time.

7 illustrates changes in azimuth and elevation with respect to time using Equation 4 above.

8 shows the change in the signal-to-noise ratio of the measurement radar with respect to the distance obtained as a result of the measurement radar tracking state simulation.

A general radar beacon equation for representing the signal-to-noise ratio change of the measurement radar is shown in Equation 5 below.

[m]는 레이더 파장,

[m]는 비콘 펄스 폭, R[m]는 레이더와 표적사이의 거리, K[J/deg.]는 볼츠만 상수, T_S는 시스템 잡음 온도, L[dB]은 레이더 비콘 추적 간 손실을 나타내는 파라미터이다.Where P _B [Watt] is the peak power of the beacon transmitter, G _TB [dB] is the target directional beacon transmit antenna gain, G _R [dB] is the radar antenna gain,

[m] is the radar wavelength,

[m] is the beacon pulse width, R [m] is the distance between the radar and the target, K [J / deg.] is the Boltzmann constant, T _S is the system noise temperature, and L [dB] is the loss between radar beacon tracking. Parameter.

,

로부터 결정되므로, 상기 수학식 5는 하기 수학식 6과 같이 나타낼 수 있다.In Equation 5, the distance R between the radar and the target becomes a value that changes with time, and the target direction beacon transmission antenna gain is G _TB due to the change in the trajectory and attitude of the target.

,

Since it is determined from, Equation 5 can be expressed as Equation 6 below.

As shown in FIG. 8, the change in the signal-to-noise ratio of the measurement radar with respect to the distance is shown by comparing the case according to the present invention and the case where the antenna gain is assumed to be constant.

In addition, in the present invention, the characteristics of the measurement radar can be modeled using Equation 6 above, and the servo loop for driving the antenna pedestal can be modeled by a simple PI controller. The transfer function of the servo loop for modeling may be as shown in Equation 7 below.

Here, the input to the servo loop models the monopulse tracking of the measurement radar to become an error signal in an elevation direction in a multipath interference situation.

FIG. 9 is a diagram illustrating a tracking danger section of a measurement radar based on the result of FIG. 8. This is shown by setting the tracking failure risk interval to be presented as the end result of the present invention.

As shown in FIG. 9, it can be seen that the section in which the signal-to-noise ratio is drastically reduced by 10 dB or more is set as compared to the case where the antenna gain is assumed to be constant. That is, the first sharply decreasing portion of the signal-to-noise ratio in FIG. 8 corresponds to the third tracking risk section of FIG. 9, and the second rapidly decreasing portion of the second signal-rising ratio in FIG. Corresponds to. In addition, the third steepest decrease in the signal-to-noise ratio in FIG. 8 corresponds to the third tracking risk section in FIG. 9.

10 is a diagram illustrating a simulation system 100 for tracking a target antenna signal of a measurement radar according to the present invention.

The system includes a target modeling unit 110, a measurement radar simulator 120, and an algorithm driver 130.

The target modeling unit 110 forms a target in consideration of the target antenna electromagnetic field analysis, the expected trajectory of the target, and the posture change of the target.

The electromagnetic field analysis of the target antenna is measured by placing the actual antenna in the omnidirectional chamber for comparison with the antenna pattern measured for the antenna designed or introduced in the actual shape. After modeling using the same ground plane as the jig used above, the results are compared with each other. Once the design and analysis of the antenna has been completed, the CAD data is produced by editing the approximated model or the actual shape. An antenna designed on the CAD fixture is mounted to perform electromagnetic field analysis according to conditions.

The measurement radar simulator 120 performs modeling on the measurement radar in consideration of the transmission and reception characteristics of the radar and the driving of the servo loop. The servo loop for driving the antenna pedestal can be modeled with a simple PI controller. Here, the input to the servo loop models the monopulse tracking of the measurement radar to become an error signal in an elevation direction in a multipath interference situation.

The algorithm driver 130 checks the tracking error of the radar and also determines the measurement risk. In the algorithm driving unit, the tracking algorithm is driven to calculate the electromagnetic characteristics of the target according to the expected trajectory and the movement of the target and to calculate a specific variable according to the antenna selection. After that, an error according to the servo characteristic of the radar is calculated and applied to the calculated value. Therefore, through this, the tracking error of the radar can be finally confirmed, and the radar measurement risk is finally determined by adding a state determination method to determine the measurement risk accordingly.

100: simulation system
110: target modeling unit
120: instrumentation radar simulator
130: algorithm driving unit

Claims (9)

In the simulation method for tracking the target antenna signal in the measurement radar,
Modeling the target using electromagnetic field analysis of the target antenna, predicted trajectory of the target, and attitude change data;
Modeling the measurement radar in consideration of the transmission / reception characteristics of the radar and the driving of the servo loop; And
Driving a tracking algorithm to determine the tracking error of the radar and determine the measurement risk,
Driving the tracking algorithm,
Performing calculations on specific characteristics according to antenna characteristics and antenna selection of the target according to the expected trajectory and movement of the target; And
And calculating and applying an error according to the servo characteristic of the radar to the calculated value. delete The method of claim 1,
Electromagnetic field analysis of the target antenna,
Selecting a target and an antenna model mounted on the target;
Independently performing simulations on the antennas to obtain results for electric field analysis and antenna characteristics for the selected antennas;
Comparing the radiation pattern measurement of the actual antenna with the performed simulation value;
Preparing a simulation shape for a target and converting it into a model for electromagnetic analysis when the antenna is mounted;
Setting a position and number of target antennas; And
And mounting the antenna model to a target model to perform an electromagnetic analysis of a target antenna. The method of claim 1,
The step of modeling the target has a field characteristic obtained in a full-wave (full-wave) method, the simulation method for tracking the target antenna signal in the measurement radar. The method of claim 1,
The modeling of the target may include applying a rotation matrix for a roll, pitch, and yaw posture change to a target's position with respect to time. The method of claim 1,
And the servo loop is modeled using a PI controller. A simulation system for tracking a target antenna signal in a measurement radar,
A target modeling unit for modeling a target using electromagnetic field analysis of the target antenna, predicted trajectory of the target, and attitude change data;
A measurement radar simulator for performing modeling on the measurement radar in consideration of transmission and reception characteristics of the radar and driving of the servo loop; And
Including an algorithm driver for driving the tracking algorithm to check the radar tracking error and determine the measurement risk,
The algorithm driver,
In the measurement radar characterized in that the calculation of the electromagnetic characteristics of the target according to the expected trajectory and movement of the target and a specific variable according to the antenna selection, and calculating the error according to the servo characteristics of the radar to the calculated value Simulation system for tracking target antenna signals. delete 8. The method of claim 7,
And the servo loop is modeled using a PI controller.

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