JPH11160418A - Quasi-target signal generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an evaluation test of a radar equal to the case that an arbitrary target is flown without flying an airplane, by providing a transmitting and receiving antenna, etc., for receiving and retransmitting a transmitted signal of a radar to be tested. SOLUTION: A transmitting and receiving antenna 1 receives a signal transmitted by a radar 100 to be tested, and retransmits a quasi-target signal generated, and an amplifier 2A amplifies the transmitted signal received. A transmitted signal detecting circuit 6 detects the transmission timing and the amplitude value of the transmitted signal, and an input circuit 12 inputs the kind, distance, and speed of a target machine. An arithmetic and logic circuit 10 reads information of the effective reflecting area of the radar from the inputted kind and distance of a quasi-target machine and a received transmission timing from a memory circuit 11, and computes the distance, amplitude, and speed. The quasi-target signal generated by a doppler control circuit 9, a delay circuit 7, a synthesizing circuit 13, etc., is converted into a signal in an original radar frequency band by a mixer 3B, amplified by an amplifier 2B and retransmitted from the transmitting and receiving antenna 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a pseudo target signal generator, and more particularly to a pseudo target signal generator used for performing an evaluation test of a radar apparatus in an actual radio wave emission state.

[0002]

2. Description of the Related Art A radar apparatus radiates a pulsed electromagnetic wave into space, receives a reflected wave from a target, and measures the distance based on the time.

Conventionally, according to the first prior art, such a radar apparatus detects its maximum by actually flying a target aircraft or the like and emitting a radio wave from the radar apparatus to obtain a reflected signal of the target aircraft. Evaluation tests such as distance and accuracy are being conducted. FIG. 5 shows a state in which an evaluation test of a conventional radar device is performed.

A conventional pseudo target signal generator as a second prior art is disclosed in, for example, Japanese Patent Laid-Open No. 58-0 / 1983.
As shown in JP-A-007881 and JP-A-59-020876, this is implemented by generating a pseudo target signal by a pseudo target signal generator without directly radiating radio waves from an antenna and directly inputting the signal to a receiver. ing. FIG. 6 is a block diagram showing the embodiment.

Next, a radar simulator disclosed in Japanese Patent Application Laid-Open No. 01-201173 as a third conventional example is not used in a state where radio waves are radiated from an actual antenna, but a beam from a radar device is also used. Based on the operation control signal, a pseudo-radar received signal modulated by the reference IF signal and the reference RF signal is generated,
This is performed by directly inputting the pseudo target signal to the receiver.

[0006]

However, the evaluation test of the conventional radar apparatus described above has the following drawbacks.

As a problem of the first conventional example, in order to perform an evaluation test of a radar device by radiating actual radio waves from the aerial, it is necessary to actually fly a target aircraft or the like and perform a test.

In this case, it is necessary to actually fly an aircraft or the like.
Is determined, it is impossible to perform an evaluation test of the radar device with an arbitrary RCS. In addition, a great deal of time and effort was required to increase the number of test flights and fly at an arbitrary distance and speed.

Further, the problems of the second and third conventional examples are described in the above-mentioned JP-A-58-000781 and JP-A-59-00007.
In the case of an evaluation test using the pseudo target signal generator disclosed in Japanese Patent Publication No. 20876 or the radar simulator disclosed in Japanese Patent Application Laid-Open No. 01-201173, the pseudo target signal is actually input from the receiver end. It was impossible to perform tests including antenna characteristics by emitting radio waves, and it was impossible to perform evaluation tests of radar devices including antennas.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been made in order to solve the above-mentioned drawbacks inherent in the prior art. Therefore, an object of the present invention is to provide an arbitrary distance within the coverage area of the radar device under test. A pseudo target signal generator is installed in the system to receive the signal actually transmitted by the radar device under test, generate a pseudo target signal based on the signal, and set the model, distance, and speed of the pseudo target arbitrarily. A new pseudo target signal generation that enables an evaluation test of a radar device equivalent to flying an arbitrary target without flying an aircraft or the like while emitting actual radio waves It is to provide a device.

[0011]

In order to achieve the above object, a pseudo target signal generator according to the present invention receives a high frequency band signal transmitted by a radar device under test and transmits / receives the pseudo target signal again. An antenna, an amplifier for amplifying a high-frequency band signal received by the transmitting / receiving antenna to a specified level, a mixer for frequency-converting the high-frequency band signal amplified by the amplifier to an intermediate frequency band, and a local unit for this frequency conversion A STALO that generates an oscillation signal, a distribution circuit that distributes the output of the mixer to a Doppler control circuit, a delay circuit, and a transmission signal detection circuit, an input circuit that inputs a model, a distance, and a speed of a target aircraft or the like; A signal detection circuit for receiving the intermediate frequency band signal distributed by the distribution circuit and detecting the reception timing and amplitude of the transmission signal of the radar device under test; Input the timing and amplitude information detected by the output circuit, read the necessary RCS information from the target model input from the input circuit, calculate the input distance, delay time according to the speed, amplitude, Doppler frequency An arithmetic circuit for outputting, a storage circuit for storing the input RCS of various aircraft, etc., a delay circuit for adding a delay time to the intermediate frequency band signal based on a control signal from the arithmetic circuit output, and an output of the delay circuit And an amplitude control circuit for controlling an amplitude value according to the RCS and the distance of the target machine based on a control signal from the arithmetic circuit, and a target moving speed based on a control signal from the arithmetic circuit for an intermediate frequency band signal. Doppler control circuit that controls the change in Doppler frequency according to the input signal, a synthesis circuit that inputs and synthesizes the output of these control circuits, and the frequency band of the original radar device under test Configured with a mixer for frequency conversion, and an amplifier for amplifying to a prescribed level and outputs to the transmission and reception antenna in EP.

Further, when a pseudo clutter signal such as cloud fog or mountain range is generated at an arbitrary distance and a pseudo interference signal is generated, the distance, type and pseudo interference signal type of the pseudo clutter can be input to the input circuit. An input circuit with added functions, a storage circuit for additionally storing pseudo clutter specifications such as fog and mountain ranges and interference signal specifications in the storage circuit, and a pseudo clutter distance, type and interference signal input from the input circuit. An arithmetic circuit that reads information of each of the storage circuits from the type of the arithmetic circuit and calculates and outputs parameters for controlling the pseudo clutter signal generation circuit and the pseudo interference signal generation circuit; a pseudo clutter distance based on a control signal from the arithmetic circuit; A pseudo-clutter signal generation circuit for controlling the amplitude value according to the type;
A pseudo-jam signal generating circuit for controlling the amplitude value and the like of the pseudo-jam signal based on a control signal from the arithmetic circuit; an output of the pseudo-clutter signal generating circuit; an output of the pseudo-jam signal generating circuit; an output of the Doppler control circuit; And a combining circuit for combining the output of the control circuit.

[0013]

Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a first embodiment of a pseudo target signal generator according to the present invention, and FIG. 3 shows a second embodiment of the pseudo target signal generator according to the present invention. It is a block block diagram.

[1] Description of Configuration Referring to FIG. 1, the configuration of the pseudo target signal generation device 200 according to the first embodiment of the present invention receives a transmission signal of the radar device under test 100, and A transmitting / receiving antenna 1 for retransmitting the generated pseudo target signal, an amplifier 2A for amplifying the received transmission signal to a prescribed level, and a mixer 3A for converting the output of the amplifier 2A to an intermediate frequency band;
ST for generating a local oscillation signal for this frequency conversion
ALO (local oscillation circuit) 4, a distribution circuit 5 for distributing the output of the mixer 3A, and a transmission signal detection circuit for detecting the transmission timing and amplitude value of the transmission signal from the intermediate frequency band signal distributed by the distribution circuit 5 6, an input circuit 12 for inputting the model, distance and speed of the target aircraft, a storage circuit 11 for storing the input RCS information of the target aircraft (radar effective reflection area information of various aircraft, etc.), and an input circuit 12. An arithmetic circuit 10 that reads out the RCS information from the input model of the pseudo target, the distance, the received transmission timing, and the model of the target machine, and calculates and outputs the distance, amplitude, and speed, and a delay time based on the output of the arithmetic circuit 10. Delay circuit 7 for controlling
An amplitude control circuit 8 for controlling an amplitude value adapted to the RCS of the target machine; a Doppler control circuit 9 for controlling a Doppler frequency from a speed set by the input circuit 12;
And a synthesizing circuit 13 for synthesizing output signals of the amplitude control circuit 8 and the Doppler control circuit 9. The pseudo target signal generated by these circuits is converted by the mixer 3B into a signal in the original radar frequency band. The signal is amplified by the amplifier 2B and retransmitted from the transmitting / receiving antenna 1.

FIG. 3 is a block diagram showing a second embodiment according to the present invention. In the pseudo target signal generator shown in FIG. 1, a pseudo clutter signal for generating pseudo clutter such as clouds, fog, and mountains is shown. This is an embodiment in which a generation circuit 14 and a pseudo interference signal generation circuit 15 for generating an interference signal that simulates the addition of an interference signal to a radar device are added.

[2] Description of Operation FIG. 2 is a time chart showing the operation of one embodiment of the pseudo target signal generating device according to the present invention. The operation of the present invention will be described below with reference to FIG.

A pseudo target signal generator 200 according to the present invention
Is placed at a distance R from the radar device under test 100 and no time delay is performed, that is, if there is no time delay, the transmission pulse radiated from the radar device under test 100 The time T reflected from the target signal generator 200 and returned is represented by [Equation 1] (FIG. 2- (A)).

[Equation 1] T = 2R / C (where C is the speed of light) From [Equation 1], the reception time T of the pulse corresponding to the installation distance R of the pseudo target signal generator 200 is determined by the set pseudo target distance R '. And the pseudo target signal generator installation distance R is delayed by Δt corresponding to the difference (FIG. 2- (C)), and the distance R ′ is pseudo-variable by changing the time T ′ detected on the receiver side. (FIG. 2- (D)).

The power (Pr) received by the radar device under test is represented by [Equation 2].

[Equation 2] Pr = Pt · G ² · λ ² · σ / {(4π) ³ · R ' ⁴ } where Pt: transmission power of the radar apparatus, G: antenna gain of the radar apparatus, λ: The transmission wavelength of the radar device, σ: target machine RCS.

From [Equation 2], Pt: transmission power, G: antenna gain, λ: transmission wavelength are known as parameters of the radar apparatus, and therefore R ′: pseudo target distance and σ: pseudo target RCS By setting, the power level of the received signal can be determined.

That is, the pseudo target distance R 'and the pseudo target RC
By setting S, the received power received by the radar device under test can be calculated.

Since the value of the RCS differs depending on the target aircraft or the like, the RCS information is stored in the storage circuit 11.
Is to be stored.

Next, in recent radar apparatuses, the mainstream is a radar apparatus which measures and uses Doppler information of a received signal, and utilizes that a reflected wave undergoes a Doppler shift by a target relative velocity. The moving speed can be detected and only the moving target can be displayed.

If there is relative motion between the target and the radar, the frequency of the reflected wave causes a Doppler frequency due to the Doppler effect, and the received frequency is shifted from the transmitted frequency by the Doppler frequency. The receiving device of the radar device detects the Doppler frequency to detect the speed. If the Doppler frequency is fd and the target velocity in the radial direction of the radar is V, it can be expressed by [Equation 3].

[Equation 3] fd = 2V / λ Accordingly, by setting the velocity V, the Doppler frequency f
d can be determined, and speed information received on the radar device side can be simulated.

That is, the Doppler control circuit 9 generates a Doppler frequency adapted to the speed calculated by the arithmetic circuit 10.

Next, the flow of signals will be described with reference to FIG.

The pseudo target signal generator 200 of the present invention installed at an arbitrary distance R receives the transmission pulse signal of the radar device under test 100 at the position of time T.

The received signal is amplified to a specified level by the amplifier 2A, and is converted to an intermediate frequency band determined by the mixer 3A and the STALO4. The received signal converted into the intermediate frequency band is sent by the distribution circuit 5 to the transmission signal detection circuit 6, the delay circuit 7, the Doppler control circuit 9, and the arithmetic circuit 10.

At this time, the transmission signal detection circuit 6 detects the transmission timing and amplitude level of the intermediate frequency band and outputs them to the arithmetic circuit 10. In the arithmetic circuit 10, the target model, the distance and the speed input from the input circuit 12 and the R
Delay time (distance), RCS (amplitude) based on CS information,
The speed (Doppler frequency) is calculated and output to the delay circuit 7, the amplitude control circuit 8, and the Doppler control circuit 9.

In response to a control signal from the arithmetic circuit 10, the delay circuit 7 controls Δt corresponding to the distance shown in FIG. 2C with respect to the intermediate frequency, and the amplitude control circuit 8 controls the distance and RCS.
Control the amplitude value of ΔA according to. Further, the Doppler control circuit 9 controls a frequency change (Δfd) by a Doppler frequency control signal calculated by the arithmetic circuit 10 based on the speed V input by the input circuit 12.

Next, the outputs of the amplitude control circuit 8 and the Doppler control circuit 9 are combined by the combining circuit 13, and the combined signal is converted into the original frequency band of the radar device under test by the mixer 3B, and is specified by the amplifier 2B. , And is retransmitted from the transmitting / receiving antenna 1.

As shown in FIG. 2D, the radar reception signal from the radar device under test 100 receives a time T 'corresponding to the set distance, and a level A' corresponding to the distance and the target RCS. It is received as a pseudo target signal moving at a speed V.

Next, a second embodiment of the present invention will be described in detail with reference to FIG.

In the second embodiment shown in FIG. 3, the means for generating a pseudo target signal is the same as the means described with reference to FIGS. 1 and 2, but in addition to the above-described pseudo target signal generating means, Pseudo clutter signal generation circuit 14 and pseudo interference signal generation circuit 1
5 is different from the above-described first embodiment.

Referring to FIG. 3, the input circuit 12 can input the distance and type of the pseudo clutter and the type of the pseudo interference signal in addition to the model, distance and speed of the pseudo target. In the storage circuit 11, in addition to the RCS information of the target aircraft,
The specifications according to the type of the pseudo clutter and the specifications according to the type of the pseudo interference signal are stored.

Next, the arithmetic circuit 10 reads out the specifications from the storage circuit 11 in accordance with the distance and the type of the pseudo clutter input by the input circuit 12 and the type of the pseudo interference signal, and sets the set distance R A time T 時間 and an amplitude value A ゛ according to 演算 are calculated and sent to the pseudo clutter signal generation circuit 14 and the pseudo interference signal generation circuit 15.

The pseudo clutter signal generation circuit 14 generates a pseudo clutter signal according to the control signal calculated by the arithmetic circuit 10. Further, the pseudo interference signal generation circuit 15 generates a pseudo interference signal based on the control signal calculated by the arithmetic circuit 10.

The output of the pseudo clutter signal generation circuit 14
The output of the pseudo interference signal generation circuit 15, the output of the amplitude control circuit 8, and the output of the Doppler control circuit 9 are combined by the combining circuit 13 and converted into the original frequency band of the radar device under test by the mixer 3B. At 2B, the signal is amplified to a specified level and retransmitted from the transmitting / receiving antenna 1.

In the radar device under test 100, the received signal is received as shown in the time chart of FIG.
A pseudo target signal at a distance R ′ and a pseudo clutter signal at a distance R 検 出 are detected.

[0043]

As described in detail above, the pseudo target signal generator according to the present invention is installed at an arbitrary distance within the coverage area of the radar device under test, so that it emits actual radio waves, and It is possible to perform an evaluation test equivalent to a case where a target aircraft of an arbitrary RCS is flown without actually flying the target aircraft.

Further, the provision of the pseudo clutter signal generation circuit and the pseudo interference signal generation circuit makes it possible to set the clutter signal and the pseudo interference signal at an arbitrary distance. In addition, it is possible to perform an evaluation test simulating the simulated clutter and the interference radio wave environment without actually flying an aircraft or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a pseudo target signal generator according to the present invention.

FIG. 2 is a time chart showing the operation of the embodiment of the pseudo target signal generator according to the present invention.

FIG. 3 is a block diagram showing a second embodiment of the pseudo target signal generator according to the present invention.

FIG. 4 is a time chart showing an operation of the pseudo target signal generator according to the second embodiment of the present invention.

FIG. 5 is a block diagram showing a flight evaluation test of a conventional radar device.

FIG. 6 is a block diagram showing a conventional pseudo target signal generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transmission / reception aerial vehicle 2A, 2B ... Amplifier 3A, 3B ... Mixer 4 ... STALO 5 ... Distribution circuit 6 ... Signal detection circuit 7 ... Delay circuit 8 ... Amplitude control circuit 9 ... Doppler control circuit 10 ... Operation circuit 11 ... Storage circuit 12 ... Input circuit 13 ... Synthesis circuit 14 ... Pseudo clutter signal generation circuit 15 ... Pseudo interference signal generation circuit 100 ... Radar device under test 200 ... Pseudo target signal generation device

Claims (2)

[Claims] A pseudo target signal generator used for an evaluation test of a radar device in a state of emitting radio waves, a transmitting / receiving antenna for receiving and retransmitting a high frequency band signal transmitted by the radar device under test, An amplifier for amplifying the high frequency band signal to a specified level, a mixer for converting the amplified high frequency band signal to an intermediate frequency band, a STALO for generating a local oscillation signal for this frequency conversion, and the mixer A distribution circuit that distributes the output intermediate frequency band signal to a Doppler control circuit, a delay circuit, and a signal detection circuit described later, an input circuit that inputs a model, a distance, and a speed of an aircraft or the like that is a pseudo target, and the distribution circuit distributes the signal. A signal detection circuit which receives the intermediate frequency band signal to be received and detects the reception timing and amplitude of the radar device under test transmission signal from the intermediate frequency band signal,
Radar effective reflection area information (RCS information) for various aircraft, etc.
A Doppler control circuit, a delay circuit, and an amplitude control circuit, which are described later, based on the output of the signal detection circuit, the RCS information of the storage circuit, and the model, distance, and speed input from the input circuit. And a delay circuit for calculating and outputting a delay time, an amplitude and a Doppler frequency, respectively, and an intermediate frequency band signal output from the distribution circuit, and a delay according to a distance input based on a control signal from the calculation circuit. A delay circuit that adds time, an amplitude control circuit that receives an output of the delay circuit, and controls the amplitude value according to the RCS and the distance of the RCS of the target machine based on a control signal from the arithmetic circuit; A Doppler control circuit for inputting a frequency band signal and controlling a Doppler frequency change corresponding to a target moving speed based on a control signal from the arithmetic circuit; Circuit for inputting the output of the Doppler control circuit and the output of the Doppler control circuit, for synthesizing the outputs, a mixer for frequency-converting the intermediate frequency band signal output by the synthesizing circuit to a high frequency band signal of the radar device under test, and the mixer And an amplifier for amplifying the output of the antenna to a predetermined level and outputting the amplified output to the transmitting / receiving antenna. 2. The input circuit according to claim 1, further comprising a function of inputting a distance, a type of a clutter and a type of an interference signal, and a clutter specification for the storage circuit according to claim 1. A storage circuit having a function of also storing information and specification information of disturbance; a distance between the specification information of the storage circuit and an output of the signal detection circuit according to claim 1 and a pseudo clutter input to the input circuit; The arithmetic circuit according to claim 1, wherein a function of calculating a distance, an amplitude value, and an amplitude value of the interference signal of the pseudo clutter from the type and the type of the interference signal and outputting a control signal to the pseudo clutter signal generation circuit and the pseudo target signal generation circuit is provided. An added arithmetic circuit, a pseudo-clutter signal generation circuit that generates a pseudo-clutter signal by a control signal from the arithmetic circuit, and a pseudo-jam signal that generates a pseudo-jam signal by a control signal from the arithmetic circuit The pseudo target signal generator according to claim 1, further comprising a generation circuit.