JP3769624B2 - Pseudo target - Google Patents

Description

  The present invention can control the reflected radio wave as if a stationary object is moving on the flying object side, and the meeting position (also called the meeting point, the position where the flying object is closest to the object, The Doppler frequency received by the flying object side at the position where the flying object passes just beside the object) is related to the pseudo target that can be zero.

  Conventionally, this type of pseudo target includes a type that reflects the radio wave radiated from the flying object 1 as it is, such as the radio wave reflecting sphere 2 as shown in FIG. There are some which reflect and reflect a certain Doppler frequency component on the radio wave radiated from the flying object 1 by adjusting the switching frequency like the variable reflectance Luneberg lens 3. Also, there is a translator 4 as shown in FIG. 9 that controls the amount of phase of a built-in phase controller to reflect the Doppler frequency superimposed on the radio wave radiated from the flying object 1.

However, among the three methods described above, the type shown in FIG. 7 is reflected by the radio wave reflecting sphere 2 or the like when the speed of the flying object 1 traveling straight is V and the frequency of the transmitted radio wave is f _0. The frequency of the reflected radio wave toward the flying object 1 is also f ₀ , and the Doppler frequency received by the flying object 1 can only detect the Doppler frequency of the flying object itself, so the same frequency as the reflected radio wave from the ground etc. Since it is buried in the region, it is very difficult for the flying object 1 to detect a pseudo target that reflects the radio wave emitted from the flying object 1 such as the radio wave reflecting sphere 2 as it is.

Further, in the type shown in FIG. 8, when the speed of the flying object 1 traveling straight is V and the frequency of the transmission radio wave is f ₀ , the Doppler frequency Δf is superimposed by the reflectivity variable type Luneberg lens 3 or the like. The frequency of the reflected radio wave toward the flying object 1 is f ₀ + Δf, and unlike the type of FIG. 7, it can be detected in a frequency range different from the frequency range of the reflected radio wave such as the ground. Although it is easy to detect, this type is not practical due to the drawbacks of switching noise generation and a narrow deviation frequency range. In addition, the Doppler frequency at the meeting position is not 0, and the frequency component shifted by the control always remains, so that it is impossible for the flying object to recognize the stationary object as if it were moving. Is possible.

  The type shown in FIG. 9 overcomes the drawbacks of the switching noise and the narrow frequency deviation width of the type shown in FIG. 8, but the problem described in the latter half of the type shown in FIG. The Doppler frequency at the position does not become 0, and the frequency component shifted by the control always remains, so that the flying object cannot be recognized as a moving object by the flying object side. It is done.

  The present invention has been made to overcome the above-mentioned disadvantages and problems associated with the background, and provides a pseudo target that can recognize a stationary object as if it were moving on the flying object side. It is intended to provide.

  Other objects and novel features of the present invention will be clarified in embodiments described later.

In order to achieve the above object, the invention of claim 1 of the present application receives a radio wave radiated from a flying object, adds a Doppler frequency component to shift the frequency of the received radio wave, and radiates it as a reflected radio wave to the outside. In the pseudo target,
The flying object detector for detecting the flying object in front, the detection signal output from the flying object detector as a trigger, the control unit for controlling the reflected radio wave, and the control signal of the control unit A high-frequency unit that radiates as a reflected radio wave by superimposing a Doppler frequency component on the received radio wave received from the flying object,
The flying object is detected in front, and the Doppler frequency is set to 0 at the meeting position where the flying object passes the high-frequency part according to the preset flying object speed.

  The pseudo target according to the invention of claim 2 of the present application is that, in claim 1, the control unit and the high-frequency unit are stationary, but the reflected radio wave is apparently controlled by the control unit. It is characterized by acting as if it is moving towards the gill body.

  The invention of claim 3 of the present application is characterized in that in claim 1 or 2, the high-frequency unit has a phase controller, and the control unit has a Doppler frequency received by the flying object at the meeting position of 0. The phase controller is controlled.

  According to the present invention, there is an effect that a stationary object is detected as a pseudo target as if it is moving on the flying object side.

  Hereinafter, as a best mode for carrying out the present invention, an embodiment of a pseudo target will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram associated with operation using a pseudo target. In this figure, a fixed target pseudo target 10 includes a flying object detector 11, a control unit 12, and a high-frequency unit 13. A transmission radio wave (frequency f ₀ ) radiated from the flying object 1 is a high-frequency wave. The reflected radio wave received by the unit 13 and controlled by the control unit 12 is radiated from the high frequency unit 13 to the flying object 1. The control part 12 receives the information (detection signal) which detected the flying object output from the flying object detector 11 arrange | positioned ahead of the high frequency part 13 (flying object arrival side), and this is received as a trigger signal. Start program control. The operational conditions at this time are that the flying object 1 moves at a constant linear velocity of V, the high-frequency unit 13 and the flying object 1 meet at a certain distance D, and the flying object. The position where the flying object detector 11 detects 1 is that the high-frequency part 13 must have a sufficiently large distance R compared to the distance D where the flying object 1 and the high-frequency part 13 meet. . As will be described later with reference to FIG. 3, the high-frequency unit 13 includes a reception antenna 21 and a transmission antenna 26, but the distance between them is negligibly small compared to the distance D. The meeting position is the position where the flying object 1 passes by.

Here, the Doppler frequency fd on the flying object side of the object that actually moves facing the flying object is the velocity V of the flying object, the velocity v of the object moving opposite, and the flying object. Assuming that the frequency f ₀ to be transmitted, the angle θ until the meeting, and the speed of light c,
fd = 2 × (f ₀ / c) × (V + v) × cos θ (1)
It is expressed. However, the flying object and the moving object shall meet in parallel. FIG. 2 shows these positional relationships and Doppler frequency characteristics obtained on the flying object side.

In the case of using the conventional radio wave reflection sphere 2 of FIG. 7 and the like, since there is only a Doppler frequency corresponding to the velocity V of the flying object 1, the above equation (1) is
fd = 2 × (f ₀ / c) × V × cos θ (2)
Thus, the Doppler frequency characteristic is 0 at the meeting point.

8 and 9, the Doppler frequency corresponding to the velocity v corresponding to the moving object can be reflected by the reflectivity variable Luneberg lens 3 or the translator 4, but the Doppler frequency is omnidirectional. Since the angle dependence disappears and the flying object side detects the Doppler frequency corresponding to the velocity v even at the meeting point, the equation (1) is
fd = 2 × (f ₀ / c) × (V × cos θ + v) (3)
It becomes.

  Therefore, in the present invention, the control unit 12 and the high-frequency unit 13 are stationary (fixed arrangement) by controlling the phase amount of the translator shown in FIG. 9 so as to give the angle dependency to v in the expression (3). However, it makes the flying body recognize as if it is actually moving in opposition.

FIG. 3 shows a basic block configuration of the high-frequency unit 13 of the embodiment of FIG. This block configuration is the same as that of the translator shown in FIG. Specifically, the transmission radio wave (frequency f ₀ ) radiated from the flying object 1 is received by the receiving antenna 21, amplified to a certain level by the high frequency amplifier 22, and then passed through the phase controller 23 to receive the radio wave. The amount of frequency shift is added to the signal, and the reflected radio wave is returned from the transmitting antenna 26 to the flying object 1 using the variable attenuator 24 and the high frequency amplifier 25 so that the desired reflected power is obtained. Here, the problem is that the control amount of the phase controller by a normal translator is given by a constant voltage signal or the like. For this reason, a Doppler frequency corresponding to v remains at the meeting position as shown in Equation (3). This is not the same as the actual moving object. Therefore, by generating a control signal input to the phase controller 23 in the control unit 12, it is possible to recognize the same movement as the actual moving object on the flying object side.

  FIG. 4 shows a basic block configuration of the control unit 12. Based on a fixed basic oscillation frequency of the oscillator 31, the clock generation circuit 32 generates a clock signal according to a clock generation cycle determined by the CPU 33, and the control signal operates the counter 34 with this clock signal (by counting the clock). Is output. The clock generation cycle is variably controlled by the CPU 33 so as to be an integral multiple of the cycle of the output signal of the oscillator 31. The CPU 33 that controls the clock generation circuit 32 is a clock that is determined by manually setting the setting information (meeting distance D, flying object speed V, flying object detector and high-frequency distance R) shown in FIG. The generation period can be calculated. The CPU 33 and the counter 34 detect the trigger signal that the flying object detector 11 has detected the flying object 1 and start its operation. The CPU 33 operates the clock generation circuit 32, and the counter 34 The control signal is output to the phase controller 23 shown in FIG.

FIG. 5A shows, for example, in the arrangement shown in FIG. 1, the meeting distance D = 10 m, the flying object speed V = 300 m / s, and the initial value Δf _{0 of the} Doppler frequency to be superimposed on the reflected radio wave from the pseudo target. = 40 kHz (emission radio wave f ₀ = 10 GHz and v = 600 m / s equivalent), result of the case where the distance R between the flying object detector 11 and the high frequency unit 13 is not controlled by the control unit 12 It is. Here, when the control is not performed, the operation is the same as that of the translator of FIG. 9, and the expression (3) is applied. Further, FIG. 5B shows that the flying object is detected when the meeting distance D = 10 m, the flying object speed V = 300 m / s, and the object speed v = 600 m / s in the arrangement shown in FIG. Doppler frequency characteristics. Here, the frequency radiated from the flying object is set to f ₀ = 10 GHz. In this case, equation (1) is applied.

  That is, it can be understood that the control amount should be determined so that FIG. 5A has the Doppler frequency characteristic of FIG. Here, the details of the phase controller used in the translator shown in FIG. 9 are described in a commercially available reference book. In brief, the phase amount of the phase controller (for example, , 0 °, 15 °, 30 °, 45 °, 90 °) (in this case, corresponding to one cycle from 0 ° to 90 °) is a Doppler received by the flying object. The frequency will be determined. That is, a normal translator is operated when the period for sequentially changing the phase amount is fixed.

For the pseudo target shown in the embodiment of the present invention, it is important to synchronize this phase amount with the trigger timing of the flying object detector 11 and control it to be 0 at the meeting position. Is a modification of equation (1)
fd = 2 × (f ₀ / c) × V × cos θ + 2 × (f ₀ / c) × v × cos θ
= Sl + S2 (1) '
Then, since the preceding term S1 is a Doppler frequency corresponding to the velocity component of the flying object itself, the cos θ portion of the latter term is the basic amount of control. Ultimately, if the latter term S2 is given to the phase controller as a controlled variable, the Doppler frequency obtained on the flying object side can be detected as if it were moving a stationary object.

Here, cos θ is geometrically calculated from FIG.
cos θ = x / (x ² + D ² ) ^1/2 (4)
It becomes. Note that x is the distance that the flying object 1 should move to the meeting position. Next, assuming that the time from the flying object detector 11 to the meeting position is T,
cos θ = (V × T) / {(V × T) ² + D ² } ^1/2 (4) ′
It becomes. In other words, it is only necessary to divide the time so that T = 0 until the flying object detector 11 detects the flying object 1 and reaches the meeting position.

Further, since the distance between the flying object detector 11 and the high frequency unit 13 is R, the initial value of T is T = R / V (5) in advance.
Determined by Therefore, the control amount S2 is
S2 = 2 × (f ₀ / c) × v × (V × T) / {(V × T) ² + D ² } ^1/2 (6)
Thus, the controlled variable input to the phase controller 12 is expressed by equation (6) with T as a variable.

For example, when R = 100 m, V = 300 m / s, D = 10 m, initial value of Doppler frequency Δf ₀ = 40 kHz (equivalent to v = 600 m / s at f ₀ = 10 GHz), R = 100 m 6 (a), and FIG. 6 (b) shows the difference between the result of FIG. 5 (b) and the result of FIG. 6 (a). Here, the difference generated in FIG. 6B is a calculation error, and thus can be ignored. From this result, it can be seen that the pseudo target can be controlled as if it were almost the same as the actual motion.

  Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

It is embodiment of the pseudo target which concerns on this invention, Comprising: It is a geometric positional relationship figure of a flying body and a pseudo target. It is explanatory drawing of the Doppler frequency which the flying body in a real moving object receives. It is a specific block diagram of the high frequency part in an embodiment. It is a specific block diagram of a flying object detector and a control part. It is a graph which shows the relationship between the distance of a conventional translator and the actual calculation example of a real moving object, and a Doppler frequency. It is a graph which shows the difference of the result of the actual calculation example of a pseudo target, and the result of the actual calculation example of an actual moving object and a pseudo target. It is explanatory drawing of the Doppler frequency which the flying body in a radio wave reflection sphere etc. receives. It is explanatory drawing of the Doppler frequency which the flying body in a reflectance variable type Luneberg lens receives. It is explanatory drawing of the Doppler frequency which the flying body in a translator receives.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flying object 2 Radio wave reflection sphere 3 Reflectivity variable type Luneberg lens 4 Translator 10 Pseudo target 11 Flying object detector 12 Control part 13 High frequency part 21 Reception antenna 22, 25 High frequency amplifier 23 Phase controller 24 Variable attenuator 31 Oscillator 32 Clock generation circuit 33 CPU
34 counters

Claims (3)

In a pseudo target that receives radio waves radiated from a flying object, adds a Doppler frequency component to shift the frequency of the received radio waves, and radiates the reflected radio waves to the outside.
The flying object detector for detecting the flying object in front, the detection signal output from the flying object detector as a trigger, the control unit for controlling the reflected radio wave, and the control signal of the control unit A high-frequency unit that radiates as a reflected radio wave by superimposing a Doppler frequency component on the received radio wave received from the flying object,
A pseudo target, wherein the flying object is detected in front and the Doppler frequency is set to 0 at a meeting position where the flying object passes the high-frequency part according to the predetermined flying object speed. 2. The control unit according to claim 1, wherein the control unit and the high-frequency unit are stationary, but operate as if they are moving toward the flying object by controlling the reflected radio wave by the control unit. Pseudo goal. The said high frequency part has a phase controller, The said control part controls the said phase controller so that the Doppler frequency which the said flying body receives is 0 in the said meeting position. Pseudo goal.

Images