WO2020003513A1

WO2020003513A1 - Radar device

Info

Publication number: WO2020003513A1
Application number: PCT/JP2018/024897
Authority: WO
Inventors: 孝行中西; 道生瀧川
Original assignee: 三菱電機株式会社
Priority date: 2018-06-29
Filing date: 2018-06-29
Publication date: 2020-01-02
Also published as: JPWO2020003513A1; JP6797330B2

Abstract

This radar device comprises a beam orientation calculation unit (24) for calculating the beam orientation of shortwave radio waves on the basis of a phase velocity calculated by a phase velocity calculation unit (23) and an incidence angle and ground shortwave-radio-wave phase velocity estimated by the phase velocity calculation unit (23), and is configured such that a beam orientation setting unit (25) sets the orientations of shortwave radio waves emitted from transmission antennas (6-1) to (6-N) and shortwave radio waves received by reception antennas (7-1) to (7-M) to the beam orientation calculated by the beam orientation calculation unit (24).

Description

Radar equipment

The present invention relates to a radar apparatus for setting a beam directing direction of a radio wave in a short wave band.

It is known that high frequency (HF) radio waves radiated from the ground are refracted in the ionosphere and propagate far out of line of sight.
If a radar device for detecting a target uses radio waves in the short wave band reflected on the ionosphere, it is possible to detect a target that is located far away from the line of sight.

Patent Document 1 below discloses a propagation path calculation device that calculates a propagation path of a radio wave by obtaining a refraction angle of a radio wave in a short wave band with reference to data indicating a relationship between an electron density and a height in an ionosphere. Is disclosed.

JP 2009-69982 A

If the conventional radar apparatus can use the propagation path calculation device disclosed in Patent Document 1, it is possible to obtain a propagation path of a radio wave in a short wave band.
However, the propagation path calculation device disclosed in Patent Document 1 does not calculate the radiation direction of the short wave radio wave from the propagation path of the short wave radio wave.
Therefore, even if the conventional radar device can use the propagation path calculation device disclosed in Patent Document 1, it cannot calculate an appropriate radio wave radiation direction for detecting a target. In other words, there is a problem that a target existing in a desired area may not be detected by irradiating a target with radio waves.

The present invention has been made to solve the above-described problems, and has as its object to obtain a radar device capable of detecting a target existing in a desired area.

A radar apparatus according to the present invention includes an altitude calculation unit that calculates an altitude of an ionosphere that reflects radio waves in a short wave band using a position of a radio wave source that emits radio waves in a short wave band, A phase velocity calculator that calculates the phase velocity of the short wave radio wave, and estimates the incident angle of the short wave radio wave to the ionosphere using the phase velocity, and the phase velocity, the incident angle, and the ground calculated by the phase velocity calculator. A beam pointing direction calculation unit that calculates the beam pointing direction of the short wave radio wave from the phase velocity of the short wave radio wave in the direction of the short wave radio wave radiated from the transmitting antenna and the short wave band received by the receiving antenna. A beam pointing direction setting unit that sets each of the directions of the radio waves to the beam pointing direction calculated by the beam pointing direction calculation unit.

According to the present invention, from the phase velocity calculated by the phase velocity calculation unit, the incident angle and the phase velocity of the radio wave in the short wave band on the ground, the beam directivity calculation unit that calculates the beam directivity of the radio wave in the short wave band is provided. The beam pointing direction setting unit sets each of the direction of the short wave radio wave radiated from the transmitting antenna and the direction of the short wave radio wave received by the receiving antenna to the beam pointing direction calculated by the beam pointing direction calculating unit. The radar device was configured as described above. Therefore, the radar device according to the present invention can detect a target existing in a desired area.

1 is a configuration diagram illustrating a radar device according to a first embodiment. FIG. 2 is a hardware configuration diagram illustrating hardware of a signal processing device 20 of the radar device illustrated in FIG. 1. FIG. 2 is a hardware configuration diagram of a computer when the signal processing device 20 is realized by software or firmware. 9 is a flowchart illustrating a processing procedure when the signal processing device 20 is realized by software or firmware. FIG. 3 is a configuration diagram illustrating a correlation determination unit 21 of the radar device according to the first embodiment. FIG. 3 is a configuration diagram illustrating an altitude calculation unit 22 of the radar device according to the first embodiment. FIG. 7 is a configuration diagram illustrating a radar device according to a second embodiment. FIG. 8 is a hardware configuration diagram illustrating hardware of a signal processing device 20 of the radar device illustrated in FIG. 7. FIG. 7 is an explanatory diagram showing a correspondence relationship between a linear distance Rd from the radar device to a plurality of radio wave sources 1 and a beam directing direction θ ₀ , and interpolation data indicating a relationship between the linear distance Rd and the beam directing direction θ ₀ after interpolation processing. . FIG. 9 is a configuration diagram illustrating a radar device according to a third embodiment. FIG. 11 is a hardware configuration diagram illustrating hardware of a signal processing device 20 of the radar device illustrated in FIG. 10. FIG. 9 is a configuration diagram showing a transmitting antenna 6-n (n = 1, 2,..., N) whose beam directing direction is changed by adjusting the antenna element length. FIG. 9 is a configuration diagram showing a receiving antenna 7-m (m = 1, 2,..., M) in which a beam directing direction is changed by adjusting an antenna element length.

Hereafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing a radar device according to the first embodiment.
FIG. 2 is a hardware configuration diagram showing hardware of the signal processing device 20 of the radar device shown in FIG.
In FIG. 1, a radio wave source 1 is installed at a position separated by a linear distance Rd from the radar apparatus shown in FIG. 1, and radiates radio waves in a short wave band. The frequency of the short wave radio wave is 3 to 30 MHz.
The frequency f and the linear distance Rd of the radio wave in the short wave band radiated from the radio wave source 1 are known in the radar device shown in FIG.

The transmitter 2 generates a radar signal as a transmission signal, and outputs the radar signal to the distributor 3 and an analog / digital converter (hereinafter, referred to as an “A / D converter”) 13.
The distributor 3 divides the radar signal output from the transmitter 2 into N (N is an integer equal to or greater than 1) pieces, and outputs each of the divided radar signals to the phase control unit 4.

The phase control unit 4 includes N phase shifters 4-1 to 4-N.
Phase shifter 4-1 ~ 4-N adjusts the phase of each radar signals output from the distributor 3 in accordance with the control signal C _p which is output from the beam pointing direction setting unit 25, after the phase adjustment of the respective The radar signal is output to variable gain amplifiers 5-1 to 5-N.
The amplitude control section 5 includes N variable gain amplifiers 5-1 to 5-N.
Variable gain amplifier 5-1 ~ 5-N in accordance with a control signal C _a, which is output from the beam pointing direction setting unit 25, adjusts the amplitude of each of the radar signals output from the phase shifter 4-1 ~ 4-N Then, the respective radar signals after the amplitude adjustment are output to the transmitting antennas 6-1 to 6-N.
The transmission array antenna 6 includes N transmission antennas 6-1 to 6-N.
When receiving the respective radar signals from the variable gain amplifiers 5-1 to 5-N, the transmitting antennas 6-1 to 6-N radiate short-wave radio waves into space as radar waves.
As the transmission antennas 6-1 to 6-N, a dipole antenna, a monopole antenna, or the like can be used.

The receiving array antenna 7 includes M (M is an integer of 1 or more) receiving antennas 7-1 to 7-M.
The receiving antennas 7-1 to 7-M receive the radio waves in the short-wave band reflected on the ionosphere, and output the received signals of the radio waves to the variable gain amplifiers 8-1 to 8-M.
As the receiving antennas 7-1 to 7-M, a dipole antenna or a monopole antenna can be used.
The amplitude control unit 8 includes M variable gain amplifiers 8-1 to 8-M.
Variable gain amplifiers 8-1 ~ 8-M in accordance with a control signal C _a, which is output from the beam pointing direction setting unit 25, adjusts the amplitude of each received signal output from the receiving antennas 7-1 ~ 7-M , And outputs the received signals after the amplitude adjustment to the phase shifters 9-1 to 9-M.
The phase control section 9 includes M phase shifters 9-1 to 9-M.
Phase shifter 9-1 ~ 9-M adjusts the phase of each received signal output from the variable gain amplifiers 8-1 ~ 8-M according to the control signal C _p which is output from the beam pointing direction setting unit 25 , And outputs the received signals after the phase adjustment to the combiner 10.
The combiner 10 combines the M received signals output from the phase shifters 9-1 to 9-M, and outputs a combined signal, which is the combined received signal, to the receiver 12.

The receiving antenna 11 receives a direct wave of a short wave radio wave radiated from the radio wave source 1 and outputs a received signal of the direct wave to the receiver 12.
As the receiving antenna 11, a dipole antenna, a monopole antenna, or the like can be used.
Receiver 12 demodulates the combined signal output from combiner 10 and outputs the combined signal after demodulation to A / D converter 13.
Further, the receiver 12 demodulates the received signal of the direct wave output from the receiving antenna 11 and outputs the demodulated received signal to the A / D converter 13.
The A / D converter 13 converts the radar signal output from the transmitter 2 from an analog signal to a digital signal, and outputs the digital signal to the correlation determination unit 21 as transmission data Tx.
Further, A / D converter 13, a synthesized signal output from the receiver 12 from an analog signal to a digital signal, and outputs the correlation determination unit 21 the digital signal as the composite data Rx _S.
Further, A / D converter 13, a received signal output from the receiver 12 from an analog signal to a digital signal, and outputs the correlation determination unit 21 the digital signal as received data Rx _D.

The signal processing device 20 includes a correlation determination unit 21, an altitude calculation unit 22, a phase speed calculation unit 23, a beam directivity calculation unit 24, a beam directivity direction setting unit 25, and a distance speed calculation unit 26.
The correlation determination unit 21 is realized by, for example, the correlation determination circuit 31 illustrated in FIG.
Correlation determination unit 21 determines a transmission data Tx outputted from the A / D converter 13, the correlation between the composite data Rx _S output from the A / D converter 13.
Correlation determination unit 21, if there is a correlation between the transmission data Tx and synthetic data Rx _S, and outputs the synthesized data Rx _S the distance speed calculation unit 26.
Correlation determination unit 21, if there is no correlation between the transmission data Tx and synthetic data Rx _S, outputs a respective combined data Rx _S and the received data Rx _D altitude calculation unit 22.

The altitude calculation unit 22 is realized by, for example, the altitude calculation circuit 32 illustrated in FIG.
The altitude calculation unit 22 calculates the time difference Δt between the reception time of the direct wave radio wave not reflected by the ionosphere and the reception time of the radio wave reflected by the ionosphere in the short wave band radio waves radiated from the radio wave source 1. calculate.
That is, the height calculation unit 22, while delaying the received data Rx _D output from the correlation determination unit 21 in the time direction, the delay time correlation is observed between the received data Rx _D synthetic data Rx _S t _d , The time difference Δt between both reception times is calculated.
The altitude calculator 22 calculates the altitude h of the ionosphere using the time difference Δt and the position of the radio wave source 1, and outputs the altitude h of the ionosphere to the phase velocity calculator 23.

The phase speed calculation unit 23 is realized by, for example, a phase speed calculation circuit 33 illustrated in FIG.
The phase velocity calculation unit 23 estimates the electron density ed _h of the ionosphere at the altitude h output from the altitude calculation unit 22 with reference to an IRI (International Reference Ionosphere) model, and calculates a short wave band at the altitude h from the electron density ed _h. to calculate the radio wave phase velocity v _h.
The phase velocity calculation unit 23 refers to the IRI model, than height h, in estimating the electron density _{ed h + 1} of the ionosphere in the upper one altitude (h + 1), advanced from the electron density _{ed h + 1 (h + 1} ) The phase speed v _{h + 1} of the short wave radio wave is calculated.
The altitude (h + 1) one level higher than the altitude h is one level higher in the model resolution of the IRI model.
Phase velocity calculation unit 23, and the phase velocity v _h of a radio wave short-wave band in altitude h, the height (h + 1) of a radio wave short-wave band in the phase velocity v _{h + 1} Tokyo, radio waves incident angle theta _h of HF band for ionospheric presume.
The phase velocity calculator 23 outputs the phase velocity v _h and the incident angle θ _h of the radio wave to the beam directivity calculator 24.

The beam pointing direction calculation unit 24 is realized by, for example, a beam pointing direction calculation circuit 34 illustrated in FIG.
The beam directing direction calculation unit 24 calculates a beam of the short wave radio wave from the phase speed v _h and the incident angle θ _{h of} the radio wave output from the phase speed calculation unit 23 and the phase speed v ₀ of the short wave radio wave on the ground. The pointing direction θ ₀ is calculated.
The beam pointing direction calculation unit 24 outputs the beam pointing direction θ ₀ of the short wave radio wave to the beam pointing direction setting unit 25.

The beam direction setting unit 25 is realized by, for example, a beam direction setting circuit 35 shown in FIG.
Beam pointing direction setting unit 25 for setting the direction of the radio wave of the short-wave band radiated from the transmission antenna 6-1 ~ 6-N in the beam pointing direction theta _0, shift of the phase shifter 4-1 ~ 4-N The phase amount and the gains of the variable gain amplifiers 5-1 to 5-N are controlled.
The beam pointing direction setting unit 25 for setting the direction of the radio wave of the short-wave band, which is received by the receiving antennas 7-1 ~ 7-N in the beam pointing direction theta _0, the variable gain amplifiers 8-1 ~ 8-N And the phase shift amounts of the phase shifters 9-1 to 9-N are controlled.

The distance speed calculation unit 26 is realized by, for example, a distance speed calculation circuit 36 illustrated in FIG.
Distance velocity calculation unit 26, the synthesized data Rx _S output from the correlation determination unit 21, calculates the respective distances L and the target speed V to the target.

In FIG. 1, each of a correlation determination unit 21, an altitude calculation unit 22, a phase velocity calculation unit 23, a beam directivity calculation unit 24, a beam directivity setting unit 25, and a distance speed calculation unit 26, which are components of the signal processing device 20, However, it is assumed that the hardware is realized by dedicated hardware as shown in FIG. That is, it is assumed that the signal processing device 20 is realized by the correlation determination circuit 31, the altitude calculation circuit 32, the phase velocity calculation circuit 33, the beam directivity direction calculation circuit 34, the beam directivity direction setting circuit 35, and the distance speed calculation circuit 36. are doing.
Here, each of the correlation determination circuit 31, the altitude calculation circuit 32, the phase speed calculation circuit 33, the beam direction calculation circuit 34, the beam direction setting circuit 35, and the distance speed calculation circuit 36 is, for example, a single circuit, a composite circuit. , A programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

The components of the signal processing device 20 are not limited to those realized by dedicated hardware. Even if the signal processing device 20 is realized by software, firmware, or a combination of software and firmware, Good.
Software or firmware is stored as a program in the memory of the computer. The computer means hardware for executing a program, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor). I do.
FIG. 3 is a hardware configuration diagram of a computer when the signal processing device 20 is realized by software or firmware.
When the signal processing device 20 is realized by software or firmware, the correlation determination unit 21, the altitude calculation unit 22, the phase velocity calculation unit 23, the beam direction calculation unit 24, the beam direction setting unit 25, and the distance speed calculation unit 26 A program for causing a computer to execute the processing procedure is stored in the memory 41. Then, the processor 42 of the computer executes the program stored in the memory 41.
FIG. 4 is a flowchart illustrating a processing procedure when the signal processing device 20 is realized by software or firmware.

FIG. 2 shows an example in which each of the components of the signal processing device 20 is realized by dedicated hardware, and FIG. 3 shows an example in which the signal processing device 20 is realized by software or firmware. However, some components of the signal processing device 20 may be realized by dedicated hardware, and the remaining components may be realized by software or firmware.

FIG. 5 is a configuration diagram illustrating the correlation determination unit 21 of the radar device according to the first embodiment.
5, the correlation processing section 21a sends data Tx outputted from the A / D converter 13, and acquires the respective combined data Rx _S and the received data Rx _D.
Correlation processing section 21a is performed a correlation processing between the transmission data Tx and synthetic data Rx _S, and outputs the correlation processing result to the correlation determination unit 21b.
Correlation processing section 21a outputs the respective transmission data Tx, combined data Rx _S and the received data Rx _D to the correlation determination unit 21b.
Correlation determination processing section 21b, correlation processing result output from the correlation processing unit 21a is, if indicates that the transmission data Tx and synthetic data Rx _S are correlated, combined data Rx _S distance speed calculating section 26 Output to
Correlation determination processing section 21b, the correlation processing result output from the correlation processing unit 21a is, if indicates that the transmission data Tx and synthetic data Rx _S is not correlated, the combined data Rx _S and the received data Rx _D Each is output to the altitude calculation unit 22.

FIG. 6 is a configuration diagram illustrating the altitude calculation unit 22 of the radar device according to the first embodiment.
6, the correlation processing section 22a, while delaying the received data Rx _D output from the correlation determination unit 21 in the time direction, carried out correlation processing with the received data Rx _D synthetic data Rx _S, correlation The result is output to the time difference calculator 22b.
Time difference calculating unit 22b, correlation processing result output from the correlation processing unit 22a is, the received data Rx _D synthetic data Rx _S to search the delay time t _d of the received data Rx _D indicating that are correlated.
Time difference calculating unit 22b, a direct wave signal reception time of which is not reflected in the ionosphere, as a time difference Δt between the signal reception time, which is reflected in the ionosphere, and outputs the delay time t _d to the distance calculation unit 22c .

Distance calculating unit 22c, the delay from the time t _d that is output from the time difference calculating section 22b, the receiving array calculates the distance dr of the difference between the reception distance and linear distance Rd at the antenna 7, altitude calculating unit reflecting the distance dr Output to 22d.
The reflection altitude calculation unit 22d holds, as the position of the radio wave source 1, the linear distance Rd between the radar device and the radio wave source 1 shown in FIG.
The reflection altitude calculation unit 22d calculates the altitude h of the ionosphere using the linear distance Rd and the distance dr output from the distance calculation unit 22c, and outputs the altitude h of the ionosphere to the phase velocity calculation unit 23.

Next, the operation of the radar device shown in FIG. 1 will be described.
There are a plurality of radio sources 1 whose linear distance Rd from the radar device shown in FIG. 1 is known, and the frequency f of the short-wave radio waves radiated from each of the plurality of radio sources 1 is known in the radar device. Shall be.
In the radar device shown in FIG. 1, for example, when detecting a target whose linear distance from the radar device is around 100 km, using a radio wave radiated from the radio source 1 having a linear distance Rd from the radar device of about 100 km, Set the beam direction.
In the radar device shown in FIG. 1, for example, when detecting a target whose linear distance from the radar device is around 200 km, radio waves radiated from the radio wave source 1 having a linear distance Rd from the radar device of about 200 km are used. To set the beam direction.

The receiving antenna 11 has a substantially horizontal beam direction (a direction at an elevation angle of about 0 degrees) so that a direct wave of a short-wave band radio wave radiated from the radio wave source 1 (a radio wave not reflected by the ionosphere) can be received. Is set to
The receiving antennas 7-1 to 7-M have a substantially vertical beam direction (a direction having an elevation angle of about 90 degrees) so as to be able to receive shortwave radio waves reflected from the ionosphere after being radiated from the radio wave source 1. ) Is set to

Here, for convenience of explanation, it is assumed that the radar device shown in FIG. 1 detects a target whose linear distance from the radar device is around 100 km.
When the receiving antenna 11 receives the direct wave of the radio wave radiated from the plurality of radio sources 1, the receiver 12 selects the radio wave radiated from the radio source 1 having a linear distance Rd of about 100 km from the plurality of direct waves. Extract the waves directly.
Since the frequency f of the radio wave radiated from each of the plurality of radio sources 1 is registered in the receiver 12, the receiver 12 selects the radio source 1 having a linear distance Rd of about 100 km from the plurality of direct waves. Can extract the direct wave of the radio wave radiated from.
When the receiver 12 extracts a direct wave of a radio wave radiated from the radio source 1 having a linear distance Rd of about 100 km, the receiver 12 demodulates the received signal of the extracted direct wave, and converts the demodulated received signal into an A / D converter 13. Output to
A / D converter 13 receives the received signal from the receiver 12, the received signal is converted from an analog signal to a digital signal, and outputs the correlation determination unit 21 the digital signal as received data Rx _D.

The receiving antennas 7-1 to 7-M receive the short-wave radio waves emitted from the radio wave source 1 and reflected by the ionosphere.
When the receiving antennas 7-1 to 7-M receive the radio waves in the short wave band reflected on the ionosphere, the variable gain amplifiers 8-1 to 8-M adjust the amplitude of the reception signals of the respective radio waves, and Are output to the phase shifters 9-1 to 9-M.
Upon receiving the respective received signals from the variable gain amplifiers 8-1 to 8-M, the phase shifters 9-1 to 9-M adjust the phases of the respective received signals and convert the respective received signals after the phase adjustment. Output to the synthesizer 10.
Upon receiving the received signals from the phase shifters 9-1 to 9-M, the combiner 10 receives the received signals of the radio waves radiated from the radio source 1 having a linear distance Rd of about 100 km from the received signals. Is extracted.
Since the frequency f of the radio wave radiated from each of the plurality of radio sources 1 is registered in the synthesizer 10, the synthesizer 10 radiates from the radio source 1 having a linear distance Rd of about 100 km from the received signal. It is possible to extract the received signal of the transmitted radio wave.
The combiner 10 combines the extracted M received signals and outputs a combined signal, which is the combined received signal, to the receiver 12.
When receiving the combined signal from combiner 10, receiver 12 demodulates the combined signal and outputs the combined signal after demodulation to A / D converter 13.
A / D converter 13 receives the composite signal from the receiver 12, the combined signal is converted from an analog signal to a digital signal, and outputs the correlation determination unit 21 the digital signal as the synthesized data Rx _S

The transmitter 2 generates a radar signal and outputs the radar signal to each of the distributor 3 and the A / D converter 13.
Upon receiving the radar signal from the transmitter 2, the A / D converter 13 converts the radar signal from an analog signal to a digital signal, and outputs the digital signal to the correlation determination unit 21 as transmission data Tx.
Here, the transmitter 2 outputs a radar signal to each of the distributor 3 and the A / D converter 13. However, in this stage, the beam directivity direction setting unit 25, since no setting the beam pointing direction theta _0, beam pointing direction setting unit 25, until the setting of the beam pointing direction theta _0, the transmitter 2 , The radar signal may not be output.

Correlation processing section 21a of the correlation determination unit 21, carried receives the transmission data Tx from the A / D converter 13, a transmission data Tx, the correlation between the composite data Rx _S output from the A / D converter 13 Then, the correlation processing result is output to the correlation determination processing section 21b (step ST1 in FIG. 4).
Correlation itself between the transmission data Tx and synthetic data Rx _S is a detailed description thereof will be omitted since it is well known in the art.
Moreover, the correlation processing section 21a outputs the respective transmission data Tx, combined data Rx _S and the received data Rx _D to the correlation determination unit 21b.
If the correlation processing unit 21a has not received the transmission data Tx from the A / D converter 13, the correlation processing unit 21a notifies the correlation determination processing unit 21b that the correlation processing has not been performed.
Moreover, the correlation processing section 21a outputs the respective combined data Rx _S and the received data Rx _D to the correlation determination unit 21b.

Correlation determination processing section 21b, correlation processing result output from the correlation processing unit 21a is, if indicates that the transmission data Tx and synthetic data Rx _S are correlated (step of FIG. 4 ST2: in the case of YES) , and outputs the synthesized data Rx _S the distance speed calculation unit 26.
Correlation determination processing section 21b, correlation processing result output from the correlation processing unit 21a is, if indicates that the transmission data Tx and synthetic data Rx _S is not correlated (step of FIG. 4 ST2: in the case of NO) , and outputs a respective combined data Rx _S and the received data Rx _D altitude calculation unit 22.
Moreover, the correlation determination processing unit 21b, if receiving the notification that no implementing correlation processing from the correlation processing unit 21a, and outputs the respective combined data Rx _S and the received data Rx _D altitude calculation unit 22.

Correlation processing section 22a of the height calculation unit 22 receives the respective combined data Rx _S and the received data Rx _D from the correlation determination unit 21b, while delaying the received data Rx _D in the time direction, and the received data Rx _D implementing the correlation between the synthesized data Rx _S (step ST3 in FIG. 4).
Correlation itself between the received data Rx _D synthetic data Rx _S is a detailed description thereof will be omitted since it is well known in the art.
Correlation processing section 22a outputs the result of a correlation process in each of the delay time t _d to the time difference calculating section 22b.

Time difference calculating section 22b receives the result of a correlation process in each of the delay time from the correlation processing unit 22a t _d, with reference to the result of a correlation process in each of the delay time t _d, the received data Rx _D synthetic data rx _S to search the delay time _{t d} are correlated (step ST4 in FIG. 4).
Time difference calculating unit 22b, a direct wave signal reception time of which is not reflected in the ionosphere, as a time difference Δt between the signal reception time, which is reflected in the ionosphere, and outputs the delay time t _d to the distance calculation unit 22c .

Distance calculating unit 22c receives the delay time t _d from the time difference calculating portion 22b, as shown in the following equation (1), from the delay time t _d, the receiving distance and linear distance Rd of the receiving array antennas 7 Is calculated (step ST5 in FIG. 4).

In the equation (1), c is the propagation speed of the radio wave.
The distance calculation unit 22c outputs the distance dr to the reflection height calculation unit 22d.

The reflection altitude calculation unit 22d uses the linear distance Rd between the radar device and the radio wave source 1 and the distance dr output from the distance calculation unit 22c to calculate the ionosphere as shown in the following equation (2). The altitude h is calculated, and the altitude h of the ionosphere is output to the phase velocity calculator 23 (step ST6 in FIG. 4).

Upon receiving the ionospheric altitude h from the reflection altitude calculating unit 22d, the phase velocity calculating unit 23 estimates the electron density ed _h of the ionosphere at the altitude h with reference to, for example, an IRI model. The IRI model is a database showing the correspondence between altitude h and electron density ed _h . The IRI model may be held by the phase velocity calculator 23 or may be held by a device external to the radar device.
After estimating the electron density ed _h , the phase velocity calculating unit 23 calculates the phase velocity v _h of the short wave radio wave at the altitude h from the electron density ed _h as shown in the following equation (3) (see FIG. 4). Step ST7).

In Expression (3), ω is a plasma frequency determined by the electron density ed _{h of the} ionosphere, and k is a wave number.

Phase velocity calculation unit 23, for example, with reference to the IRI model, than height h, in estimating the electron density _{ed h + 1} of the ionosphere in the upper one altitude (h + 1), advanced from the electron density _{ed h + 1 (h + 1} ) The phase speed v _{h + 1} of the short wave radio wave is calculated.
The altitude (h + 1) one level higher than the altitude h is one level higher in the model resolution of the IRI model.
Phase velocity calculation unit 23, and the phase velocity v _h of a radio wave short-wave band in altitude h, the height (h + 1) of a radio wave short-wave band in the phase velocity v _{h + 1} Tokyo, radio waves incident angle theta _h of HF band for ionospheric presume.
That is, the phase velocity calculation unit 23, the phase velocity v _h and phase velocity v _{h + 1} is substituted into the following equation (4), to search the incident angle theta _h of a radio wave equation (4) is satisfied.

Radio wave short-wave band is reflected by the ionosphere when Equation (4) is the incident angle theta _h which satisfies.
The phase velocity calculator 23 outputs the phase velocity v _h and the incident angle θ _h of the radio wave to the beam directivity calculator 24.

As shown in the following equation (5), the beam pointing direction calculation unit 24 calculates the phase velocity v _h and the incident angle θ _h output from the phase velocity calculation unit 23 and the phase velocity v ₀ of the short wave radio wave on the ground. Then, the beam directing direction θ ₀ of the short wave radio wave is calculated (step ST8 in FIG. 4).
The phase velocity v ₀ radio waves of short wave band in the ground are known. Here, the ground corresponds to the altitude at which the receiving antennas 7-1 to 7-M are installed.

In Equation (5), θ _w is the beam width of the short-wave radio wave radiated from the transmitting antennas 6-1 to 6-N.
The beam pointing direction calculation unit 24 outputs the beam pointing direction θ ₀ of the short wave radio wave to the beam pointing direction setting unit 25.

Beam pointing direction setting unit 25 for setting the direction of the radio wave of the short-wave band radiated from the transmission antenna 6-1 ~ 6-N in the beam pointing direction theta _0, shift of the phase shifter 4-1 ~ 4-N The phase amount and the gains of the variable gain amplifiers 5-1 to 5-N are controlled (step ST9 in FIG. 4).
The beam pointing direction setting unit 25 for setting the direction of the radio wave of the short-wave band, which is received by the receiving antennas 7-1 ~ 7-N in the beam pointing direction theta _0, the variable gain amplifiers 8-1 ~ 8-N And the phase shift amounts of the phase shifters 9-1 to 9-N are controlled (step ST9 in FIG. 4).
That is, the beam directivity direction setting unit 25 calculates the amplitude and phase of the radar signal for setting the direction of the radio beam pointing direction theta _0.
Then, the beam directivity direction setting unit 25 outputs a control signal _{C a} indicating the amplitude in each of the variable gain amplifier 5-1 ~ 5-N and the variable gain amplifier 8-1 ~ 8-N.
The beam pointing direction setting unit 25 outputs a control signal _{C p} indicating the phase on each of the phase shifter 4-1 ~ 4-N and the phase shifter 9-1 ~ 9-N.
The process of calculating the amplitude and phase corresponding to the beam directing direction θ ₀ itself is a known technique, and a detailed description thereof will be omitted.

Upon receiving the radar signal from transmitter 2, distributor 3 divides the radar signal into N signals, and outputs the divided radar signals to phase shifters 4-1 to 4-N.
Phase shifter 4-1 ~ 4-N adjusts the phase of each radar signals output from the distributor 3 in accordance with the control signal C _p which is output from the beam pointing direction setting unit 25, after the phase adjustment of the respective The radar signal is output to variable gain amplifiers 5-1 to 5-N.
Variable gain amplifier 5-1 ~ 5-N in accordance with a control signal C _a, which is output from the beam pointing direction setting unit 25, adjusts the amplitude of each of the radar signals output from the phase shifter 4-1 ~ 4-N Then, the respective radar signals after the amplitude adjustment are output to the transmitting antennas 6-1 to 6-N.

When receiving the respective radar signals from the variable gain amplifiers 5-1 to 5-N, the transmitting antennas 6-1 to 6-N radiate short-wave radio waves into space as radar waves.
The beam pointing direction θ ₀ of the radio waves radiated from the transmitting antennas 6-1 to 6-N is set by using the radio waves radiated from the radio source 1 having a linear distance Rd from the radar device of about 100 km. It is possible to irradiate a target with a linear distance of around 100 km with a radio wave.

The receiving antennas 7-1 to 7-M receive the short-wave radio waves radiated from the transmitting antennas 6-1 to 6-N and then reflected back to the target, and convert the received radio wave signals into variable gain amplifiers. 8-1 to 8-M.
The beam pointing direction θ ₀ of radio waves received by the receiving antennas 7-1 to 7-M is set using radio waves radiated from the radio source 1 having a linear distance Rd from the radar device of about 100 km. It is possible to receive a radio wave reflected by a target whose linear distance is around 100 km.
Note that the beam pointing direction θ ₀ calculated by the beam pointing direction calculation unit 24 is an elevation angle direction, not an azimuth angle direction.
Therefore, the azimuth direction of the radio wave radiated from the transmitting antennas 6-1 to 6-N may be a direction set in advance, or may rotate in the range of 0 to 360 degrees. Good.
Further, the azimuth direction of the radio waves received by the receiving antennas 7-1 to 7-M may be a direction set in advance, or may rotate in the range of 0 to 360 degrees. Good.
However, it is necessary that the azimuth direction of the radio wave for the transmitting antennas 6-1 to 6-N and the azimuth direction of the radio wave for the receiving antennas 7-1 to 7-M be synchronized.

Variable gain amplifiers 8-1 ~ 8-M in accordance with a control signal C _a, which is output from the beam pointing direction setting unit 25, adjusts the amplitude of each received signal output from the receiving antennas 7-1 ~ 7-M , And outputs the received signals after the amplitude adjustment to the phase shifters 9-1 to 9-M.
Phase shifter 9-1 ~ 9-M adjusts the phase of each received signal output from the variable gain amplifiers 8-1 ~ 8-M according to the control signal C _p which is output from the beam pointing direction setting unit 25 , And outputs the received signals after the phase adjustment to the combiner 10.

Upon receiving the respective received signals from the phase shifters 9-1 to 9-M, the combiner 10 combines the M received signals and outputs a combined signal, which is the combined received signal, to the receiver 12.
When receiving the combined signal from combiner 10, receiver 12 demodulates the combined signal and outputs the combined signal after demodulation to A / D converter 13.
A / D converter 13 receives the composite signal from the receiver 12, the combined signal is converted from an analog signal to a digital signal, and outputs the correlation determination unit 21 the digital signal as the synthesized data Rx _S

Correlation processing section 21a of the correlation determination unit 21, a transmission data Tx outputted from the A / D converter 13, a correlation between the composite data Rx _S output from the A / D converter 13 performing the correlation process The result is output to the correlation determination processing unit 21b (step ST1 in FIG. 4).
Moreover, the correlation processing section 21a outputs the respective transmission data Tx, combined data Rx _S and the received data Rx _D to the correlation determination unit 21b.

Correlation determination processing section 21b, correlation processing result output from the correlation processing unit 21a is, if indicates that the transmission data Tx and synthetic data Rx _S are correlated (step of FIG. 4 ST2: in the case of YES) , and outputs the synthesized data Rx _S the distance speed calculation unit 26.
Here, since the receiving antennas 7-1 to 7-M are receiving shortwave radio waves that have been radiated from the transmitting antennas 6-1 to 6-N and then reflected back to the target, the transmission data Tx synthetic data Rx _S are correlated.

Distance velocity calculation unit 26 calculates the receiving the synthetic data Rx _S from the correlation determination unit 21, the combined data Rx _S, the respective distances L and the target speed V to the target (step ST10 in FIG. 4).
Process itself of calculating the combined data Rx _S, the distance L and the target velocity V to the target, the detailed description thereof is omitted because it is known in the art.

In the first embodiment, the beam direction of the short wave radio wave is determined from the phase speed calculated by the phase speed calculation unit 23, the incident angle estimated by the phase speed calculation unit 23, and the phase speed of the short wave radio wave on the ground. A beam pointing direction calculating unit 24 for calculating the direction is provided, and the beam pointing direction setting unit 25 controls the directions of the radio waves in the short wave band radiated from the transmitting antennas 6-1 to 6-N and the receiving antennas 7-1 to 7-M. The radar device is configured to set each of the directions of the radio waves in the short wave band received by the beam pointing direction calculated by the beam pointing direction calculation unit 24. Therefore, the radar device according to the first embodiment can detect a target existing in a desired area.

Embodiment 2 FIG.
In the second embodiment, a radar device that sets the beam pointing direction θ ₀ of radio waves using radio waves radiated from a plurality of radio sources 1 will be described.

FIG. 7 is a configuration diagram illustrating a radar device according to the second embodiment.
FIG. 8 is a hardware configuration diagram showing hardware of the signal processing device 20 of the radar device shown in FIG.
7 and 8, the same reference numerals as those in FIGS. 1 and 2 denote the same or corresponding parts, and a description thereof will not be repeated.
The beam directivity interpolating unit 27 is realized by, for example, a beam directivity interpolator 37 shown in FIG.
The beam pointing direction interpolation unit 27 interpolates between the plurality of beam pointing directions calculated by the beam pointing direction calculation unit 24.

Next, the operation of the radar device shown in FIG. 7 will be described.
In the radar device shown in FIG. 7, the correlation determination unit 21, the altitude calculation unit 22, the phase velocity calculation unit 23, and the beam directivity calculation unit 24 use radio waves radiated from one radio source 1 as in the first embodiment. Is used to calculate the beam pointing direction θ ₀ of the radio wave.
Further, in the radar apparatus shown in FIG. 7, the correlation determination unit 21, the altitude calculation unit 22, the phase velocity calculation unit 23, and the beam directivity calculation unit 24 are radiated from one radio source 1 different from the above radio source 1. The beam direction θ ₀ of the radio wave is calculated using the radio wave.
In the radar device shown in FIG. 7, the correlation determination unit 21, the altitude calculation unit 22, the phase velocity calculation unit 23, and the beam directivity calculation unit 24 use radio waves radiated from the plurality of radio sources 1 to The beam directing direction θ ₀ is calculated.

Beam pointing direction calculation unit 24 uses the radio wave radiated from the radio wave source 1, every time to calculate the beam pointing direction theta ₀ of the radio wave, straight line distance Rd and beam pointing direction theta ₀ of the said radio sources 1 The set is output to the beam direction interpolator 27.
FIG. 9 shows interpolation data indicating the correspondence between the linear distance Rd from the radar device to the plurality of radio wave sources 1 and the beam pointing direction θ ₀ , and the relationship between the linear distance Rd and the beam pointing direction θ ₀ after the interpolation processing. FIG.
In Figure 9, as a set of linear distance Rd and beam pointing direction theta ₀ to radio sources 1 illustrates the four sets.

When the beam pointing direction interpolation unit 27 acquires a plurality of pairs of the linear distance Rd to the radio wave source 1 and the beam pointing direction θ ₀ from the beam pointing direction calculation unit 24, the beam pointing directions θ discretely obtained are obtained. An interpolation process for interpolating between ₀ is performed.
Beam pointing direction interpolation unit 27, by carrying out the interpolation process, it is possible to identify the beam pointing direction theta ₀ corresponding to the intermediate distance between two linear distance Rd.
As the interpolation processing, processing such as least squares method or spline interpolation can be used.
The beam pointing direction interpolation unit 27 outputs interpolation data indicating the relationship between the linear distance Rd after the interpolation processing and the beam pointing direction θ ₀ to the beam pointing direction setting unit 25.

When detecting a target whose linear distance from the radar apparatus is close to X, the beam directivity setting unit 25 refers to the interpolation data output from the beam directivity interpolating unit 27 to determine the beam directivity corresponding to the linear distance X. Specify θ ₀ .
Beam pointing direction setting unit 25 for setting the direction of the radio wave of the short-wave band radiated from the transmission antenna 6-1 ~ 6-N in the beam pointing direction theta _0, shift of the phase shifter 4-1 ~ 4-N The phase amount and the gains of the variable gain amplifiers 5-1 to 5-N are controlled.
The beam pointing direction setting unit 25 for setting the direction of the radio wave of the short-wave band, which is received by the receiving antennas 7-1 ~ 7-N in the beam pointing direction theta _0, the variable gain amplifiers 8-1 ~ 8-N And the phase shift amounts of the phase shifters 9-1 to 9-N are controlled.

In the second embodiment, the radar apparatus is configured to include the beam directivity interpolating unit 27 that interpolates between the plurality of beam directivities calculated by the beam directivity calculating unit 24. Therefore, the radar device according to the second embodiment can detect the target by radiating radio waves to the target existing at an intermediate distance between the two linear distances Rd.

Embodiment 3 FIG.
The radar apparatuses according to the first and second embodiments include

amplitude controllers

5 and 8 and

phase controllers

4 and 9 to change the beam directing direction.
In the third embodiment, a radar device including a transmission digital beamforming unit 53 and a reception digital beamforming unit 54 for changing the beam directing direction will be described.

FIG. 10 is a configuration diagram showing a radar device according to the third embodiment.
FIG. 11 is a hardware configuration diagram showing hardware of the signal processing device 20 of the radar device shown in FIG.
10 and 11, the same reference numerals as those in FIGS. 1, 2, 7, and 8 denote the same or corresponding parts, and a description thereof will not be repeated.
The signal generation unit 51 is realized by, for example, a signal generation circuit 61 illustrated in FIG.
The signal generation unit 51 generates transmission data corresponding to the transmission data Tx output from the A / D converter 13 shown in FIG. 1, and outputs the transmission data to the transmission digital beamforming unit 53 and the correlation determination unit 21.

The beam direction setting unit 52 is realized by, for example, a beam direction setting circuit 62 shown in FIG.
Beam pointing direction setting unit 52, the transmitting antenna 6-1 to set the direction of the radio wave of the short-wave band, which is radiated in the beam pointing direction theta ₀ from ~ 6-N, the radio wave direction of the adjustment in the transmit digital beam forming unit 53 Control.
The beam pointing direction setting unit 52 sets the direction of the radio wave in the short-wave band received by the receiving antennas 7-1 to 7-N to the beam pointing direction θ ₀ , so that the direction of the radio wave in the reception digital beam forming unit 54 is set. To control the adjustment.

The transmission digital beamforming unit 53 is realized by, for example, a transmission digital beamforming circuit 63 shown in FIG.
The transmission digital beamforming unit 53 distributes the transmission data output from the signal generation unit 51 into N pieces.
Transmission digital beam forming unit 53, the transmitting antenna 6-1 to adjust the direction of the radio wave of the short-wave band, which is radiated in the beam pointing direction theta ₀ from ~ 6-N, control signals outputted from the beam pointing direction setting unit 52 , The transmission data after distribution is controlled.
The transmission digital beamforming unit 53 outputs the controlled transmission data to digital-to-analog converters (hereinafter, referred to as “D / A converters”) 55-1 to 55-N.

The reception digital beamforming unit 54 is realized by, for example, a reception digital beamforming circuit 64 shown in FIG.
Receiving digital beam forming unit 54, receiving antennas 7-1 to adjust the direction of the radio wave of the short-wave band received by the beam pointing direction theta ₀ by ~ 7-N, control signals outputted from the beam pointing direction setting unit 52 , The respective received data output from the A / D converters 56-1 to 56-M are controlled.
Receiving digital beam forming unit 54 combines the respective received data after control, the combined data of the received data, as data corresponding to the combined data Rx _S output from the A / D converter 13 shown in FIG. 1, Output to the correlation determination unit 21.

The digital-to-analog converter 55 includes N D / A converters 55-1 to 55-N.
The D / A converters 55-1 to 55-N convert each transmission data output from the transmission digital beamforming unit 53 from a digital signal to an analog signal, and convert each analog signal as a radar signal to the transmission antenna 6. Output to -1 to 6-N.
The analog-to-digital converter 56 includes M A / D converters 56-1 to 56-M.
The A / D converters 56-1 to 56-M convert the respective reception signals received by the reception antennas 7-1 to 7-N from analog signals to digital signals, and convert the respective digital signals into reception data. Output to the reception digital beamforming unit 54.
The A / D converter 57 converts the direct wave reception signal output from the reception antenna 11 from an analog signal to a digital signal, and converts the digital signal into reception data output from the A / D converter 13 shown in FIG. as data corresponding to rx _D, and outputs the correlation determination unit 21.

Next, the operation of the radar device shown in FIG. 10 will be described.
However, except for the signal generation unit 51, the beam directivity setting unit 52, the transmission digital beamforming unit 53, the reception digital beamforming unit 54, the digital / analog conversion unit 55, the analog / digital conversion unit 56, and the A / D converter 57, the implementation is the same. This is similar to the first and second embodiments.
Here, only portions different from the first and second embodiments will be described.

The signal generation unit 51 generates transmission data corresponding to the transmission data Tx output from the A / D converter 13 shown in FIG. 1, and outputs the transmission data to the transmission digital beamforming unit 53 and the correlation determination unit 21.
Upon receiving the beam pointing direction θ ₀ of the radio wave from the beam direction interpolating unit 27, the beam pointing direction setting unit 52 changes the direction of the short wave band radio wave radiated from the transmitting antennas 6-1 to 6-N to the beam pointing direction θ. _In order to set it to ₀ , the adjustment of the direction of the radio wave in the transmission digital beam forming unit 53 is controlled.
The beam pointing direction setting unit 52 sets the direction of the radio wave in the short-wave band received by the receiving antennas 7-1 to 7-N to the beam pointing direction θ ₀ , so that the direction of the radio wave in the reception digital beam forming unit 54 is set. To control the adjustment.

Upon receiving the transmission data from the signal generation unit 51, the transmission digital beamforming unit 53 distributes the transmission data into N pieces.
Transmission digital beam forming unit 53, the transmitting antenna 6-1 to adjust the direction of the radio wave of the short-wave band, which is radiated in the beam pointing direction theta ₀ from ~ 6-N, control signals outputted from the beam pointing direction setting unit 52 , The transmission data after distribution is controlled.
To adjust the direction of the radio wave of the short-wave band radiated from the transmission antenna 6-1 ~ 6-N in the beam pointing direction theta _0, the process itself to control the respective transmission data after the distribution are known in the art Therefore, detailed description is omitted.
The transmission digital beamforming unit 53 outputs the respective controlled transmission data to the D / A converters 55-1 to 55-N.
The D / A converters 55-1 to 55-N convert each transmission data output from the transmission digital beamforming unit 53 from a digital signal to an analog signal, and convert each analog signal as a radar signal to the transmission antenna 6. Output to -1 to 6-N.

The A / D converters 56-1 to 56-M convert the respective reception signals received by the reception antennas 7-1 to 7-N from analog signals to digital signals, and convert the respective digital signals into reception data. Output to the reception digital beamforming unit 54.
The A / D converter 57 converts the direct wave reception signal output from the reception antenna 11 from an analog signal to a digital signal, and converts the digital signal into reception data output from the A / D converter 13 shown in FIG. as data corresponding to rx _D, and outputs the correlation determination unit 21.

The reception digital beamforming unit 54 adjusts the direction of the radio wave received by the reception antennas 7-1 to 7-N to the beam pointing direction θ ₀ according to the control signal output from the beam pointing direction setting unit 52. The respective received data output from the / D converters 56-1 to 56-M are controlled.
Receiving digital beam forming unit 54 combines the respective received data after control, the combined data of the received data, as data corresponding to the combined data Rx _S output from the A / D converter 13 shown in FIG. 1, Output to the correlation determination unit 21.

The radar apparatus according to the third embodiment includes the transmission digital beamforming unit 53 and the reception digital beamforming unit 54 in order to change the beam directing direction.
The radar device including the transmission digital beamforming unit 53 and the reception digital beamforming unit 54 can detect a target existing in a desired area, similarly to the radar devices illustrated in FIGS. 1 and 7.

Embodiment 4 FIG.
In the first embodiment, a dipole antenna or a monopole antenna is used as transmission antennas 6-1 to 6-N and reception antennas 7-1 to 7-N.
In the fourth embodiment, each of transmitting antennas 6-1 to 6-N and receiving antennas 7-1 to 7-N is a radar whose beam directing direction is variable by adjusting the antenna element length. The device will be described.

FIG. 12 is a configuration diagram showing a transmitting antenna 6-n (n = 1, 2,..., N) in which the beam directing direction is changed by adjusting the antenna element length.
In FIG. 12, antenna elements 71-1 to 71-6 are elements included in transmission antenna 6-n.
The antenna element 71-1 is an element on the base end side, and is connected to the variable gain amplifier 5-n.
The antenna element 71-6 is a tip-side element.
In FIG. 12, the transmission antenna 6-n includes six antenna elements 71-1 to 71-6. However, this is only an example, and the transmitting antenna 6-n may include two or more and five or less antenna elements, or may include seven or more antenna elements. May be.

The switch 72-1 is an element for switching a connection state between the antenna element 71-1 and the antenna element 71-2.
The switch 72-2 changes the connection state between the antenna element 71-2 and the antenna element 71-3 when the switch 72-1 connects the antenna element 71-1 and the antenna element 71-2. It is a switching element.
The switch 72-3 changes the connection state between the antenna element 71-3 and the antenna element 71-4 when the switch 72-2 connects the antenna element 71-2 and the antenna element 71-3. It is a switching element.
The switch 72-4 changes the connection state between the antenna element 71-4 and the antenna element 71-5 when the switch 72-3 connects the antenna element 71-3 and the antenna element 71-4. It is a switching element.
The switch 72-5 changes the connection state between the antenna element 71-5 and the antenna element 71-6 when the switch 72-4 connects the antenna element 71-4 and the antenna element 71-5. It is a switching element.
The switching of the connection state by the switches 72-1 to 72-5 is controlled by the beam directivity setting unit 25.

FIG. 13 is a configuration diagram showing the receiving antenna 7-m (m = 1, 2,..., M) in which the beam directing direction is changed by adjusting the antenna element length.
In FIG. 13, antenna elements 81-1 to 81-6 are elements included in receiving antenna 7-m.
The antenna element 81-1 is an element on the base end side, and is connected to the variable gain amplifier 8-m.
The antenna element 81-6 is a tip-side element.
In FIG. 13, the receiving antenna 7-m includes six antenna elements 81-1 to 81-6. However, this is only an example, and the receiving antenna 7-m may include two or more and five or less antenna elements, or may include seven or more antenna elements. May be.

The switch 82-1 is an element for switching a connection state between the antenna element 81-1 and the antenna element 81-2.
The switch 82-2 changes the connection state between the antenna element 81-2 and the antenna element 81-3 when the switch 82-1 connects the antenna element 81-1 and the antenna element 81-2. It is a switching element.
The switch 82-3 changes the connection state between the antenna element 81-3 and the antenna element 81-4 when the switch 82-2 connects the antenna element 81-2 and the antenna element 81-3. It is a switching element.
The switch 82-4 changes the connection state between the antenna element 81-4 and the antenna element 81-5 when the switch 82-3 connects the antenna element 81-3 and the antenna element 81-4. It is a switching element.
The switch 82-5 changes the connection state between the antenna element 81-5 and the antenna element 81-6 when the switch 82-4 connects the antenna element 81-4 and the antenna element 81-5. It is a switching element.
The switching of the connection state by the switches 82-1 to 82-5 is controlled by the beam directivity setting unit 25.

Next, the operation will be described.
The antenna element length of the transmitting antenna 6-n is controlled by the beam directivity setting unit 25 to turn on only the switch 72-1 (connected state) and turn off the switches 72-2 to 72-5 (disconnected state). The shortest case.
The antenna element length of the transmitting antenna 6-n is the longest when the beam directivity setting unit 25 controls all the switches 72-1 to 72-5 to be ON.
The beam pointing direction setting unit 25 controls ON / OFF of the switches 72-1 to 72-5, so that the antenna element length of the transmitting antenna 6-n changes.
The elevation angles indicating the beam directing directions of the transmission antennas 6-1 to 6-N when the antenna element lengths of the transmission antennas 6-1 to 6-N are short are such that the antenna element length of the transmission antennas 6-1 to 6-N is long. It becomes smaller than the elevation angle indicating the beam directing direction of the transmitting antennas 6-1 to 6-N.
Therefore, the beam directing direction setting unit 25 controls the ON / OFF of the switches 72-1 to 72-5, so that the beam directing directions of the transmitting antennas 6-1 to 6-N can be changed.

The antenna element length of the receiving antenna 7-m is the shortest when the beam directivity setting unit 25 controls only the switch 82-1 to be ON and switches 82-2 to 82-5 to be OFF.
The antenna element length of the receiving antenna 7-m becomes the longest when the beam directivity setting unit 25 controls all the switches 82-1 to 82-5 to be ON.
When the beam directing direction setting unit 25 controls ON / OFF of the switches 82-1 to 82-5, the antenna element length of the receiving antenna 7-m changes.
The elevation angles indicating the beam directing directions of the receiving antennas 7-1 to 7-M when the antenna element lengths of the receiving antennas 7-1 to 7-M are short are such that the antenna element lengths of the receiving antennas 7-1 to 7-M are long. It becomes smaller than the elevation angle indicating the beam directing direction of the receiving antennas 7-1 to 7-M.
Therefore, the beam pointing direction setting unit 25 can change the beam pointing directions of the receiving antennas 7-1 to 7-M by controlling ON / OFF of the switches 82-1 to 82-5.

In the present invention, any combination of the embodiments, a modification of an arbitrary component of each embodiment, or an omission of any component in each embodiment is possible within the scope of the invention. .

The present invention is suitable for a radar apparatus for setting the beam directing direction of a short-wave radio wave.

1 radio source, 2 transmitter, 3 distributor, 4 phase controller, 4-1 to 4-N phase shifter, 5 amplitude controller, 5-1 to 5-N variable gain amplifier, 6 transmission array antenna, 6 -1 to 6-N transmission antenna, 7 reception array antenna, 7-1 to 7-M reception antenna, 8 amplitude control unit, 8-1 to 8-M variable gain amplifier, 9 phase control unit, 9-1 to 9 -M phase shifter, 10 combiner, 11 receiving antenna, 12 receiver, 13 A / D converter, 20 signal processor, 21 correlation judgment unit, 21a correlation processing unit, 21b correlation judgment processing unit, 22 altitude calculation unit , 22a 処理 correlation processing unit, 22b time difference calculation unit, 22c distance calculation unit, 22d reflection altitude calculation unit, 23 phase speed calculation unit, 24 beam pointing direction calculation unit, 25 beam pointing direction setting unit, 26 distance speed Calculation unit, 27 ° beam direction interpolating unit, 31 ° correlation determination circuit, 32 ° altitude calculation circuit, 33 ° phase speed calculation circuit, 34 ° beam direction calculation circuit, 35 ° beam direction setting circuit, 36 ° distance speed calculation circuit, 37 ° beam direction Interpolation circuit, 41 memory, 42 processor, 51 signal generator, 52 beam direction setting unit, 53 transmit digital beam forming unit, 54 receive digital beam forming unit, 55 digital to analog converter, 55-1 to 55-N / D / A converter, 56 analog-to-digital converter, 56-1 to 56-M A / D converter, 57 A / D converter, 61 signal generation circuit, 62 beam directivity setting circuit, 63 transmission digital beamforming circuit, 64 Receive digital beamforming circuit, 71-1 ~ 1-6 antenna elements, 72-1 to 72-5 switches, 81-1 ~ 81-6 antenna elements, 82-1 to 82-5 switches.

Claims

Using a position of a radio wave source that emits radio waves in the short wave band, an altitude calculation unit that calculates the height of the ionosphere that reflects the radio waves in the short wave band,
A phase velocity calculation unit that calculates a phase velocity of a short wave radio wave at the altitude calculated by the altitude calculation unit, and estimates an incident angle of the short wave radio wave with respect to the ionosphere using the phase velocity,
From the phase velocity calculated by the phase velocity calculator, the incident angle and the phase velocity of the radio wave in the short wave band on the ground, a beam directivity calculation unit that calculates the beam directivity of the radio wave in the short wave band,
A beam pointing direction setting unit that sets each of the direction of the short wave band radio wave radiated from the transmitting antenna and the direction of the short wave band radio wave received by the receiving antenna to the beam pointing direction calculated by the beam pointing direction calculation unit; Radar device equipped with
The altitude calculation unit is configured to calculate a time difference between a reception time of a direct wave radio wave not reflected by the ionosphere and a reception time of a radio wave reflected by the ionosphere, out of short wave band radio waves radiated from the radio wave source. The radar apparatus according to claim 1, wherein the altitude of the ionosphere is calculated using the time difference and the position of the radio wave source.
The beam pointing direction calculation unit calculates the phase speed v h , the incident angle θ h , the phase speed v 0 of the short wave radio wave on the ground, the short wave band radiated from the transmitting antenna, calculated by the phase speed calculation unit. of a radio wave and a beam width theta w by substituting the following calculation formula, the radar apparatus according to claim 1, wherein the calculating the beam pointing direction theta 0 of the radio wave of the short-wave band.
[Calculation formula]
After a short wave radio wave is radiated from the transmission antenna, a distance speed calculation unit is provided for calculating a distance to a target and a speed of the target from a reception signal of the short wave radio wave received by the reception antenna. The radar device according to claim 1, wherein:
The transmission signal of the short wave radio wave radiated from the transmission antenna, a correlation determination unit that determines the correlation between the reception signal of the short wave radio wave received by the receiving antenna,
5. The distance / speed calculation unit, when the correlation determination unit determines that there is a correlation, calculates the distance to the target and the target speed from the received signal. 6. Radar equipment.
There are multiple radio sources that emit shortwave radio waves,
The altitude calculation unit calculates the altitude of the ionosphere using the position of each radio wave source,
The phase velocity calculation unit calculates the phase velocity of radio waves in the short wave band at each altitude calculated by the altitude calculation unit,
The beam pointing direction calculation unit, using the respective phase velocities calculated by the phase speed calculation unit, to calculate the respective beam pointing directions of radio waves in the short wave band,
2. The radar device according to claim 1, further comprising a beam directing direction interpolating unit that interpolates between the plurality of beam directing directions calculated by the beam directing direction calculating unit.
A transmission digital beamforming unit that adjusts a direction of a short wave radio wave radiated from the transmission antenna,
A receiving digital beam forming unit that adjusts a direction of a short wave radio wave received by the receiving antenna,
The beam pointing direction setting unit controls the adjustment of the direction of radio waves in the transmission digital beam forming unit according to the beam pointing direction calculated by the beam pointing direction calculation unit, and the reception digital beam forming unit according to the beam pointing direction. 2. The radar apparatus according to claim 1, wherein the control of the direction of the radio wave at the step (c) is controlled.
The radar device according to claim 1, wherein each of the transmitting antenna and the receiving antenna is a dipole antenna.
The radar apparatus according to claim 1, wherein each of the transmitting antenna and the receiving antenna is a monopole antenna.
The radar device according to claim 1, wherein each of the transmitting antenna and the receiving antenna is an antenna whose beam directing direction is variable by adjusting an antenna element length.
Each of the transmitting antenna and the receiving antenna,
A plurality of antenna elements,
A switch for switching a connection state between the plurality of antenna elements,
The radar device according to claim 10, wherein the antenna element length is adjusted by controlling the switch by the beam directing direction setting unit.