JPH01313785A - Radar simulator system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field]

According to the present invention, when radio waves radiated into space by a phased array antenna of a radar irradiate a target at an arbitrary distance,
This relates to a simulator method that simulates the signal attenuation process until a reflected wave from a target is received by the antenna.

[Conventional technology]

In radar, when a target moves so that the pointing direction of the antenna is constant and the distance from the antenna is constant, only the direction changes, the radio waves emitted from the antenna are reflected by the target and the intensity of the echo radio waves received is depends on the directivity of the antenna. Conventionally, to simulate this situation, it was determined whether the target was within the beam width, and an echo was output only when the target was within the beam width. Also, when performing high-speed beam scanning using a phased array antenna,
This is equivalent to a state where the target is stationary, and the intensity of the echo radio waves received when the radio waves radiated from the antenna are reflected by the target depends on the directivity of the antenna, as described above. FIG. 2 is a schematic diagram showing the relationship among the phased array antenna A, the main beam E of the beam axis B, and the target 0. As shown in the figure, the direction of target 0 is the beam axis B of antenna A.
It is located at a position deviated by an angle θ from . This relationship is expressed in rectangular coordinates in Figure 3, where the horizontal axis is the azimuth angle θ of target 0,
The vertical axis is the received intensity (dB) in the direction of the beam axis B, and Ef is the received intensity distribution of the main beam E. The origin indicates the beam axis. FIG. 4 shows the reception intensity distribution Es when the presence or absence of echo is simulated using a conventional simulator, and the coordinates are the same as in FIG. 3. As can be seen by comparing Figures 3 and 4, this simulator determines the presence or absence of an echo by determining whether the azimuth angle θ of target 0 is located within the angle θ corresponding to the received strength of 3 dB. It depended on whether or not. Therefore, if the azimuth angle θ of target 0 is located outside the angle θ corresponding to the reception strength of 3 dB as in the illustrated example, and is within the maximum aperture angle of the main beam E, the actual The main beam received intensity distribution Ef is such that the received intensity is equal to the azimuth angle θ. However, the received intensity distribution Es obtained by the simulator shown in FIG. 4 results in a value C that is outside the beam width.

[Problem to be solved by the invention]

As mentioned above, in the conventional simulator, the eye F! Even if the azimuth angle θ of O is within the range of the main beam E, if the reception strength is below the set value, it will be simulated that there is no echo, and therefore a signal strength that depends on the directivity of the antenna cannot be obtained. The present invention was made to eliminate these drawbacks, and is a phased array antenna radar simulator in which the simulated signal strength matches the directivity of the antenna that scans the space randomly every pulse. It provides a method.

[Means to solve the problem]

The phased array antenna radar simulator method to which the present invention is applied in order to solve the above problems uses a phased array antenna that can electronically control the phase to direct the beam width and direction. When the antenna is pointed, the amount of attenuation caused by the antenna directivity caused by the difference between the target direction and the beam axis direction is calculated in real time, and the amount of attenuation caused by the antenna directivity is calculated in real time. It is characterized by simulating the process.

[Effect]

The directivity of a phased array antenna, such as that used in radar, has the property of being expressed as the product of the array directivity and the element directivity. On the other hand, when α is the azimuth angle of the target and α is the azimuth angle of the beam axis with respect to the normal to the antenna surface, and when Sin α-3ina a is zero in the calculation of array directivity, always take the peak value of the main lobe. It turns out. Therefore, if you calculate the array directivity in advance and store it in memory, even if α and α change in real time, the Sin α-5
By simply calculating inα9, the array directivity can be assigned using Sinα−3inα as an address. That is, by storing in memory decibel values obtained by separating the directivity of the phased array antenna into element directivity and array directivity, a simulation that matches the directivity of the antenna becomes possible.

【Example】

FIG. 1 is an example of a circuit diagram for implementing the phased array antenna simulator method of the present invention. In the same figure, 11 is Sin α from the beam azimuth angle α3,
12 is a conversion circuit from target azimuth a to Sinα; 13 is an address calculation circuit for allocating an array directional memory; 14 is an array directional memory circuit;
5 is an element directional memory circuit, 16 is an addition circuit, and 17 is a radio frequency (Radio Frequency) circuit.
:RFI attenuator. The operation of this circuit is to input the beam azimuth α into the conversion circuit 11 and convert it into Sin α6, and then to the address calculation circuit 13.
send to On the other hand, the conversion circuit 12 manually converts the target azimuth α into Sin α, and sends it to the address calculation circuit 13. The output Sinα of the conversion circuit 12 is simultaneously connected to the element directional memory 1.
5 address. Calculation result of address calculation circuit 13 Sinα-3inα8
is sent to array directional memory 14 as an address. Sin α-3 as an address in the array directional memory 14
When inα and sinα are respectively sent as the element directional memory 15, the array directional value stored in the array directional memory 14 and the element directional value stored in the element directional memory 15 are output, The addition circuit 16 adds the signals. Since the output of the adder circuit 16 controls the RF attenuator 17 into which a constant value is input as a large RF input, a desired degree of attenuation can be obtained. This simulates a signal strength that matches the directivity of the antenna.

【Effect of the invention】

As explained above, according to the phased array antenna radar simulator method to which the present invention is applied, the directivity of a phased array antenna that requires a random gain is separated into element directivity and array directivity. By storing this in the memory, the attenuation amount due to the directivity can be sent to the RF attenuator, which has the advantage of being controllable in real time. Highly accurate simulation that matches the directivity of the antenna is possible without performing complex complex calculations based on the direction of the target and the direction of the beam. Even if the target is within the range of the main beam, unlike in the conventional simulator system, if the reception intensity is below the set value, there is no possibility that the target will be simulated as having no echo.

[Brief explanation of the drawing]

Fig. 1 is a circuit block diagram for implementing a radar simulator system for a phased array antenna to which the present invention is applied, Fig. 2 is a diagram showing the positional relationship of operations, and Fig. 3 is a diagram showing the relationship in rectangular coordinates. , FIG. 4 is a reception strength distribution diagram when simulated using a conventional radar simulator method. A... Phased array antenna B... Beam axis 0-... Target E... Main beam Ef... Main beam reception strength 1 distribution Es...
・Reception intensity distribution by conventional radar simulator 11, l
2-=Sin conversion circuit 13...Address calculation circuit 14-...Array directional memory circuit 15...Element directional memory circuit 16...Addition circuit 17...RFillii attenuator

Claims (1)

[Claims] 1. When using a phased array antenna, which can direct the beam width and direction by electronically controlling the phase, when the beam is directed in any direction, the antenna occurs due to the difference between the target direction and the beam axis direction. A radar simulator method that calculates the amount of attenuation due to directivity in real time and simulates the process in which radio waves radiated from the antenna are reflected at a target and input to the antenna.