JP7042975B2 - Signal processing equipment, signal processing methods and radar equipment - Google Patents

Description

The present invention relates to a signal processing device, a signal processing method, and a radar device for calculating the moving speed of a measurement target.

The following Patent Document 1 discloses an in-vehicle radio wave pulse radar device that calculates a relative speed with a detected object.
In the in-vehicle radio wave pulse radar device disclosed in Patent Document 1, the signal processing device performs FFT (Fast Fourier Transform) on the beat signal generated by the receiving mixer, so that the Doppler shift occurs with the movement of the object to be detected. Calculate the frequency. Then, this signal processing device calculates the relative speed with the object to be detected from the calculated Doppler shift frequency.

Japanese Unexamined Patent Publication No. 2006-17625

In the in-vehicle radio pulse radar device disclosed in Patent Document 1, if the pulse width of the transmission pulse radiated from the transmission antenna is narrowed, the spatial resolution for the object to be detected is increased and the object to be detected is placed in the range bin. It is possible to reduce the mixing of atmospheric echoes. However, by narrowing the pulse width of the transmission pulse, the signal-to-noise ratio (SNR: Signal Noise Ratio) is lowered. In a situation where the SNR is low, if the difference between the reflectance of the transmitted pulse in the object to be detected and the reflectance of the transmitted pulse in the atmosphere is small, it becomes difficult to distinguish between the object to be detected and the atmosphere, and the object to be detected becomes difficult. There is a problem that the relative speed with and may be erroneously calculated.

The present invention has been made to solve the above-mentioned problems, and even if the difference between the reflectance of light in the measurement target and the reflectance of light in the atmosphere is small, the erroneous calculation of the movement speed in the measurement target is performed. The purpose is to obtain a signal processing device, a signal processing method and a radar device that can be prevented.

The signal processing device according to the present invention is a received signal obtained by heterodyne detection of scattered pulsed light, which is light scattered by a measurement target for transmission pulsed light generated by pulse-modulating continuous light, and continuous light. Is converted into a complex signal and the complex signal is output, and the phase data of the complex signal is obtained from the real part signal in the complex signal output from the complex signal generation unit and the imaginary part signal in the complex signal. From the phase data calculation unit to be calculated, the frequency calculation unit that calculates the frequency of the received signal based on the phase data calculated by the phase data calculation unit, and the frequency of the received signal calculated by the frequency calculation unit, the measurement target A movement speed calculation unit that calculates the Doppler shift frequency generated by movement and calculates the movement speed of the measurement target from the Doppler shift frequency , and a frequency region that converts the received signal into a signal in the frequency region and outputs a signal in the frequency region. Based on the signal output unit and the signal in the frequency region output from the frequency area signal output unit, the range bin specification processing unit that specifies the range bin including the distance to the measurement target, and the range bin identification processing unit from the received signals It is provided with a signal dividing unit that cuts out the received signal of the specified range bin and outputs the cut out received signal to the complex signal generation unit .

According to the present invention, even when the difference between the reflectance of light in the measurement target and the reflectance of light in the atmosphere is small, it is possible to prevent erroneous calculation of the moving speed in the measurement target.

It is a block diagram which shows the radar apparatus which includes the signal processing apparatus 20 which concerns on Embodiment 1. FIG. It is a hardware block diagram which shows the hardware of a part of the signal processing apparatus 20 which concerns on Embodiment 1. FIG. It is a hardware block diagram of the computer when a part of the signal processing apparatus 20 is realized by software, firmware, etc. FIG. 4A shows a transmission pulse light emitted from the radar device shown in FIG. 1, a scattered pulse light which is a transmission pulse light scattered by the sea surface, and a scattered pulse light which is a transmission pulse light scattered by the atmosphere. An explanatory diagram, FIG. 4B is an explanatory diagram showing an example of a received signal of scattered pulse light in the radar device shown in FIG. 1, and FIG. 4C is an explanatory diagram showing an example of a signal in the frequency region output from the frequency region signal output unit 24. It is a figure. It is a flowchart which shows the processing procedure of the range bin specifying part 23 in a signal processing apparatus 20. It is a flowchart which shows the processing procedure of the speed calculation unit 28 in a signal processing apparatus 20. FIG. 7A is an explanatory diagram showing the spectrum peak data AS_HT (L) at the time of measurement of the measurement target and the spectrum peak data AS_wind (L) at the time of atmospheric measurement, and FIG. 7B is an explanatory diagram showing the difference ΔAS (L) and the threshold value Th. be. FIG. 8A is an explanatory diagram showing the digital signal V _n (t) cut out by the signal dividing unit 22, and FIG. 8B shows the real part signal V _{real; n} (t) in the complex signal and the imaginary part signal in the complex signal. An explanatory diagram showing V _{imag; n} (t), FIG. 8C is an explanatory diagram showing phase data _{Sph_Ob; n} (t) of a substantially linear waveform, and FIG. 8D is a probability density distribution generated by the frequency calculation unit 31. It is explanatory drawing which shows p (f _IF ). It is a block diagram which shows the radar apparatus which includes the signal processing apparatus 20 which concerns on Embodiment 2. FIG.

Hereinafter, in order to explain the present invention in more detail, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1.
FIG. 1 is a configuration diagram showing a radar device including the signal processing device 20 according to the first embodiment.
FIG. 2 is a hardware configuration diagram showing a part of the hardware of the signal processing device 20 according to the first embodiment.
The radar device shown in FIG. 1 is a device that calculates the moving speed of a measurement target, and the measurement target may be a liquid such as a sea surface or raindrops, or an individual such as an aircraft or a ship.
In FIG. 1, the transmission pulse light generation unit 1 includes a light source 2, an optical distributor 3, and a pulse modulator 4.
The transmission pulse light generation unit 1 oscillates continuous light of a single frequency, generates transmission pulse light from the continuous light, and outputs the transmission pulse light to the transmission side optical system 6 of the transmission / reception unit 5, which will be described later.
The light source 2 oscillates continuous light of a single frequency and outputs the continuous light to the light distributor 3.
The optical distributor 3 distributes the continuous light output from the light source 2 into two, outputs one continuous light to the pulse modulator 4, and outputs the other continuous light to the optical coupler 11 described later in the transmission / reception unit 5. Output to.
When the pulse modulator 4 receives the trigger signal output from the trigger generation circuit 33 described later, the pulse modulator 4 starts pulse modulation for the continuous light output from the optical distributor 3 and repeatedly generates the transmission pulse light.
Further, the pulse modulator 4 up-converts the frequency of the generated transmission pulse light to a frequency in the radio frequency (RF: Radio Frequency) band, and transfers the up-converted transmission pulse light to the transmission side optical system 6 of the transmission / reception unit 5. Output.

The transmission / reception unit 5 includes a transmission-side optical system 6, a transmission / reception separation unit 7, a telescope 8, a scanner 9, a reception-side optical system 10, an optical coupler 11, and a light-receiving unit 12.
The transmission / reception unit 5 emits the transmission pulse light generated by the transmission pulse light generation unit 1, and then receives the scattered pulse light, which is the transmission pulse light scattered by the measurement target.
The transmission / reception unit 5 obtains a reception signal by heterodyne detection of the received scattered pulse light and the continuous light output from the light distributor 3 of the transmission pulse light generation unit 1.
The transmission / reception unit 5 outputs the received signal to the analog-digital conversion unit (hereinafter, referred to as “AD conversion unit”) 21 of the signal processing device 20 described later.

The transmission side optical system 6 adjusts the beam diameter of the transmission pulse light output from the pulse modulator 4 so that the entire transmission pulse light output from the pulse modulator 4 fits in the inlet / outlet 8a of the telescope 8. Then, the transmission pulse light after adjusting the beam diameter is output to the transmission / reception separation unit 7.
The transmission / reception separation unit 7 outputs the transmission pulse light output from the transmission side optical system 6 to the inlet / outlet 8a of the telescope 8, and the scattered pulse light output from the inlet / outlet 8a of the telescope 8 is output from the reception side optical system. Output to 10.

The telescope 8 includes inlets and outlets 8a and 8b.
When the transmission / reception separation unit 7 outputs the transmission pulse light to the inlet / outlet 8a, the telescope 8 expands the beam diameter of the transmission pulse light and outputs the transmission pulse light after the beam diameter is expanded from the inlet / outlet 8b to the scanner 9. do.
When the scattered pulse light is output from the scanner 9 to the inlet / outlet 8b, the telescope 8 reduces the beam diameter of the scattered pulse light and outputs the scattered pulse light after the beam diameter is reduced from the inlet / outlet 8a to the transmission / reception separation unit 7. do.

The scanner 9 changes the directivity direction of the transmission pulse light according to the control signal output from the directivity direction control unit 34 described later. The directivity direction of the transmitted pulse light is represented by the azimuth angle and the elevation angle.
The scanner 9 radiates the transmitted pulsed light into the atmosphere. The transmitted pulsed light emitted from the scanner 9 is scattered by the measurement target or by the atmosphere. The transmission pulse light scattered by the measurement target or the transmission pulse light scattered by the atmosphere returns to the scanner 9 as scattered pulse light.
The scanner 9 receives the returned scattered pulse light and outputs the received scattered pulse light to the inlet / outlet 8b of the telescope 8.

The receiving-side optical system 10 adjusts the beam diameter of the scattered pulsed light output from the transmitting / receiving separation unit 7 so that the entire scattered pulsed light output from the transmitting / receiving separation unit 7 fits in the input port 11a of the optical coupler 11. Then, the scattered pulsed light after adjusting the beam diameter is output to the input port 11a of the optical coupler 11.
The optical coupler 11 includes an inlet / outlet 11a.
The optical coupler 11 combines the scattered pulsed light output from the receiving side optical system 10 and the continuous light output from the light distributor 3, and the combined light of the scattered pulsed light and the continuous light is transmitted to the light receiving unit 12. Output. The frequency of the combined light is the difference frequency between the frequency of the scattered pulsed light and the frequency of the continuous light.
The light receiving unit 12 converts the combined light output from the optical coupler 11 into an electric signal, and outputs the received signal, which is an electric signal, to the AD conversion unit 21.

The signal processing device 20 includes an AD conversion unit 21, a signal division unit 22, a range bin identification unit 23, a pulse width control unit 27, and a speed calculation unit 28.
Upon receiving the trigger signal output from the trigger generation circuit 33, the AD conversion unit 21 starts a process of converting the received signal output from the light receiving unit 12 from an analog signal to a digital signal, and converts the digital signal into a signal dividing unit 22. Output to.

The signal dividing unit 22 is realized by, for example, the signal dividing circuit 41 shown in FIG.
If the range bin information output unit 26b of the range bin identification unit 23, which will be described later, has not yet output the range bin information indicating the range bin including the distance to the measurement target, the signal division unit 22 is digitally output from the AD conversion unit 21. The signal is output to the frequency domain signal output unit 24 described later in the range bin identification unit 23.
When the range bin information is output from the range bin information output unit 26b, the signal division unit 22 outputs the range bin digital from the output digital signals every time the digital signal is output from the AD conversion unit 21. Cut out the signal.
The signal division unit 22 outputs the cut out digital signal to the complex signal generation unit 29 described later of the speed calculation unit 28.

The range bin specifying unit 23 includes a frequency domain signal output unit 24 and a range bin specifying processing unit 25.
The frequency domain signal output unit 24 is realized by, for example, the frequency domain signal output circuit 42 shown in FIG.
The frequency domain signal output unit 24 converts the digital signal into a signal in the frequency domain by performing an FFT (Fast Fourier Transform) of the digital signal output from the signal division unit 22. A signal in the frequency domain is a signal indicating the light intensity of each of a plurality of frequencies.
The frequency domain signal output unit 24 outputs the frequency domain signal to the distance characteristic calculation unit 26a, which will be described later, of the range bin identification processing unit 25.

The range bin specifying processing unit 25 includes a distance characteristic calculation unit 26a and a range bin information output unit 26b.
The range bin specifying processing unit 25 identifies the range bin including the distance to the measurement target based on the frequency domain signal output from the frequency domain signal output unit 24.

The distance characteristic calculation unit 26a is realized by, for example, the distance characteristic calculation circuit 43 shown in FIG.
When the distance characteristic calculation unit 26a receives a signal in the frequency domain from the frequency domain signal output unit 24, the distance characteristic calculation unit 26a identifies the spectral peak value of the range bin corresponding to each frequency from the signal in the frequency domain.
The distance characteristic calculation unit 26a outputs the spectrum peak value of each specified range bin to the range bin information output unit 26b as the spectrum peak data at the time of atmospheric measurement or the spectrum peak data at the time of measurement of the measurement target.

The range bin information output unit 26b is realized by, for example, the range bin information output circuit 44 shown in FIG.
When the range bin information output unit 26b receives the spectrum peak data at the time of atmospheric measurement from the distance characteristic calculation unit 26a, the range bin information output unit 26b saves the spectral peak data at the time of atmospheric measurement and controls the direction of the completion signal indicating that the atmospheric measurement is completed. Output to unit 34.
When the range bin information output unit 26b receives the spectrum peak data at the time of measurement of the measurement target from the distance characteristic calculation unit 26a, the range bin information output unit 26b obtains the spectrum peak data at the time of measurement of the measurement target and the stored spectrum peak data at the time of atmospheric measurement. Specify the range bin including the distance to the measurement target.
The range bin information output unit 26b outputs range bin information indicating the specified range bin to each of the signal division unit 22 and the movement speed calculation unit 32, and outputs a completion signal indicating that the range bin identification is completed to the pulse width control unit 27. do.

The pulse width control unit 27 is realized by, for example, the pulse width control circuit 45 shown in FIG.
After the range bin is specified by the range bin information output unit 26b, the pulse width control unit 27 outputs a control signal indicating that the pulse width is narrowed to the trigger generation circuit 33, thereby performing pulse modulation of the transmission pulse light generation unit 1. The pulse width of the transmission pulse light generated by the device 4 is narrowed.
The pulse width control unit 27 also outputs a control signal indicating that the pulse width is narrowed to the signal division unit 22.

The speed calculation unit 28 includes a complex signal generation unit 29, a phase data calculation unit 30, a frequency calculation unit 31, and a movement speed calculation unit 32.
The complex signal generation unit 29 is realized by, for example, the complex signal generation circuit 46 shown in FIG.
The complex signal generation unit 29 converts the output digital signal into a complex signal each time the cut out digital signal is output from the signal division unit 22.
The complex signal generation unit 29 outputs the complex signal to the phase data calculation unit 30.

The phase data calculation unit 30 is realized by, for example, the phase data calculation circuit 47 shown in FIG.
Each time the complex signal is output from the complex signal generation unit 29, the phase data calculation unit 30 is output from the real part signal in the output complex signal and the imaginary part signal in the output complex signal. Calculate the phase data of the complex signal.
The phase data calculation unit 30 outputs the phase data of the output complex signal to the frequency calculation unit 31.

The frequency calculation unit 31 is realized by, for example, the frequency calculation circuit 48 shown in FIG.
The frequency calculation unit 31 calculates and calculates the frequency of the received signal output from the light receiving unit 12 of the transmission / reception unit 5 based on the calculated phase data each time the phase data is calculated by the phase data calculation unit 30. Save the frequency.
When the frequency calculation unit 31 stores N frequencies, it generates a probability density distribution of N frequencies and outputs the probability density distribution to the moving speed calculation unit 32. N is an integer of 2 or more.

The movement speed calculation unit 32 is realized by, for example, the movement speed calculation circuit 49 shown in FIG.
The movement speed calculation unit 32 calculates the Doppler shift frequency generated by the movement of the measurement target from the peak frequency of the probability density distribution generated by the frequency calculation unit 31.
The moving speed calculation unit 32 calculates the moving speed of the measurement target from the Doppler shift frequency.
The movement speed calculation unit 32 outputs each of the calculated movement speed and the range bin indicated by the range bin information output from the range bin information output unit 26b to the outside. Alternatively, the moving speed calculation unit 32 displays each of the calculated moving speed and the range bin indicated by the range bin information on a display or the like (not shown).

The trigger generation circuit 33 outputs a trigger signal instructing the start of operation to each of the pulse modulator 4, the AD conversion unit 21, and the directivity direction control unit 34.
Further, the trigger generation circuit 33 outputs a control signal for controlling the pulse modulator 4 to the pulse modulator 4 so that the pulse width of the transmitted pulse light becomes an initial value.
The initial value of the pulse width may be stored in the internal memory of the trigger generation circuit 33, for example, or may be given from the outside of the radar device shown in FIG.
When the trigger generation circuit 33 receives a control signal from the pulse width control unit 27 indicating that the pulse width is narrowed, the trigger generation circuit 33 controls the pulse modulation by the pulse modulator 4, and the transmission pulse light generated by the pulse modulator 4 is controlled. The pulse width of is narrower than the initial value.

When the directional control unit 34 receives the trigger signal from the trigger generation circuit 33, the directional control unit 34 outputs a control signal to the scanner 9 that controls the scanner 9 so that the directional direction of the transmission pulse light is the direction in which the measurement target does not exist. do.
When the directivity control unit 34 receives a completion signal from the range bin information output unit 26b indicating that the atmospheric measurement is completed, the scanner 9 so that the directivity direction of the transmitted pulse light is the direction in which the measurement target exists. The control signal for controlling the above is output to the scanner 9.
The direction in which the measurement target exists may be stored in the internal memory of the directivity direction control unit 34, or may be given from the outside of the radar device shown in FIG.

In FIG. 1, a signal dividing unit 22, a frequency domain signal output unit 24, a distance characteristic calculation unit 26a, a range bin information output unit 26b, a pulse width control unit 27, and a complex signal generation unit, which are some components of the signal processing device 20, are shown. 29, it is assumed that each of the phase data calculation unit 30, the frequency calculation unit 31, and the movement speed calculation unit 32 is realized by dedicated hardware as shown in FIG. That is, a part of the signal processing device 20 includes a signal division circuit 41, a frequency domain signal output circuit 42, a distance characteristic calculation circuit 43, a range bin information output circuit 44, a pulse width control circuit 45, a complex signal generation circuit 46, and a phase data calculation. It is assumed that it is realized by the circuit 47, the frequency calculation circuit 48, and the moving speed calculation circuit 49.

Here, the signal division circuit 41, the frequency region signal output circuit 42, the distance characteristic calculation circuit 43, the range bin information output circuit 44, the pulse width control circuit 45, the complex signal generation circuit 46, the phase data calculation circuit 47, the frequency calculation circuit 48, and the like. Each of the moving speed calculation circuits 49 includes, 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 these. The combination is applicable.

Some components of the signal processing device 20 are not limited to those realized by dedicated hardware, and a part of the signal processing device 20 is realized by software, firmware, or a combination of software and firmware. It may be one.
The software or firmware is stored as a program in the memory of the computer. A computer means hardware for executing a program, and corresponds to, 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). do.
FIG. 3 is a hardware configuration diagram of a computer when a part of the signal processing device 20 is realized by software, firmware, or the like.

When a part of the signal processing device 20 is realized by software or firmware, the signal dividing unit 22, the frequency domain signal output unit 24, the distance characteristic calculation unit 26a, the range bin information output unit 26b, the pulse width control unit 27, and the complex signal A program for causing a computer to execute the processing procedures of the generation unit 29, the phase data calculation unit 30, the frequency calculation unit 31, and the movement speed calculation unit 32 is stored in the memory 51. Then, the processor 52 of the computer executes the program stored in the memory 51.

Further, FIG. 2 shows an example in which each of a part of the components of the signal processing device 20 is realized by dedicated hardware, and FIG. 3 shows a part of the signal processing device 20 realized by software, firmware, or the like. An example is shown. However, this is only an example, and any component in a part of the signal processing device 20 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, or the like. ..

In the radar device shown in FIG. 1, for example, as shown in FIG. 4A, the sea surface can be measured. If the measurement target is the sea surface, the radar device shown in FIG. 1 calculates the moving speed V of the sea surface.
FIG. 4A shows the transmission pulse light emitted from the radar device shown in FIG. 1, the scattered pulse light which is the transmission pulse light scattered by the sea surface (hereinafter referred to as “scattered pulse light from the sea surface”), and the atmosphere. It is explanatory drawing which shows the scattered pulse light which is the scattered transmission pulse light (hereinafter, referred to as "scattered pulse light from the atmosphere").
As shown in FIG. 4A, if the scattered pulsed light from the sea surface and the scattered pulsed light from the atmosphere are scattered pulsed light in the same range bin, the received signal of the scattered pulsed light in the radar device shown in FIG. 1 is. It is represented as shown in FIG. 4B.
FIG. 4B is an explanatory diagram showing an example of a received signal of scattered pulsed light in the radar device shown in FIG. 1.

Next, the operation of the radar device shown in FIG. 1 will be described.
For the sake of simplicity of explanation, the radar device shown in FIG. 1 is assumed to be stopped above the sea surface to be measured, for example. Needless to say, the radar device shown in FIG. 1 may move over the sea surface.
FIG. 5 is a flowchart showing a processing procedure of the range bin specifying unit 23 in the signal processing device 20.
FIG. 6 is a flowchart showing a processing procedure of the speed calculation unit 28 in the signal processing device 20.
First, the trigger generation circuit 33 outputs a trigger signal instructing the start of operation to each of the pulse modulator 4, the AD conversion unit 21, and the directivity direction control unit 34.
Further, the trigger generation circuit 33 outputs a control signal for controlling the pulse modulator 4 to the pulse modulator 4 so that the pulse width of the transmitted pulse light becomes an initial value.
When the directional control unit 34 receives the trigger signal from the trigger generation circuit 33, the directional control unit 34 outputs a control signal to the scanner 9 that controls the scanner 9 so that the directional direction of the transmission pulse light is the direction in which the measurement target does not exist. do.
As shown in FIG. 4A, if the radar device shown in FIG. 1 is stopped above the sea surface and the measurement target is the sea surface, the directing direction control unit 34 has the directing direction of the transmitted pulse light horizontal to the sea surface. The scanner 9 is controlled so as to be in the correct direction.
Here, the directivity direction control unit 34 controls the scanner 9 so that the directivity direction of the transmitted pulse light is horizontal to the sea surface. The directing direction of the transmitted pulse light does not have to face the sea surface, and the directing direction control unit 34 may, for example, set the directed direction of the transmitted pulse light to a direction higher in altitude than the radar device shown in FIG. The scanner 9 may be controlled.

The light source 2 oscillates continuous light of a single frequency and outputs the continuous light to the light distributor 3.
When the optical distributor 3 receives continuous light from the light source 2, it distributes the continuous light into two, outputs one continuous light to the pulse modulator 4, and outputs the other continuous light to the optical coupler 11 of the transmission / reception unit 5. Output to.
Upon receiving the trigger signal from the trigger generation circuit 33, the pulse modulator 4 starts pulse modulation with respect to the continuous light output from the optical distributor 3.
The pulse modulator 4 generates a transmission pulse light having an initial value pulse width according to the control signal output from the trigger generation circuit 33.
Further, the pulse modulator 4 up-converts the frequency of the generated transmission pulse light by Δf to convert the frequency of the generated transmission pulse light into the frequency of the RF band, and the transmission pulse light having the frequency of the RF band is generated. It is output to the transmission side optical system 6 of the transmission / reception unit 5.
In the radar device shown in FIG. 1, the pulse modulator 4 up-converts the frequency of the transmission pulse light by Δf, but does not up-convert the frequency of the transmission pulse light by Δf, and transmits the transmission pulse light to the transmitting side optics. It may be output to the system 6.

When the transmission side optical system 6 receives the transmission pulse light from the pulse modulator 4, the transmission side optical system 6 adjusts the beam diameter of the transmission pulse light so that the entire transmission pulse light fits in the input port 8a of the telescope 8.
The transmission side optical system 6 outputs the transmission pulse light after adjusting the beam diameter to the transmission / reception separation unit 7.
When the transmission / reception separation unit 7 receives the transmission pulse light after adjusting the beam diameter from the transmission side optical system 6, the transmission / reception pulse light after adjusting the beam diameter is output to the input port 8a of the telescope 8.
When the transmission / reception separation unit 7 outputs the transmission pulse light to the input port 8a, the telescope 8 expands the beam diameter of the transmission pulse light and outputs the transmission pulse light after the beam diameter expansion from the input port 8b to the scanner 9. do.

The scanner 9 sets the direction of the transmission pulse light according to the control signal output from the direction control unit 34, and measures the transmission pulse light output from the input port 8b of the telescope 8 in a direction in which the measurement target does not exist. Radiates into the atmosphere.
The transmitted pulsed light emitted from the scanner 9 is scattered by the atmosphere. The transmitted pulsed light scattered by the atmosphere returns to the scanner 9 as scattered pulsed light.
The scanner 9 receives the returned scattered pulse light and outputs the received scattered pulse light to the input port 8b of the telescope 8.
When the scattered pulse light is output from the scanner 9 to the input port 8b, the telescope 8 reduces the beam diameter of the scattered pulse light and outputs the scattered pulse light after the beam diameter reduction from the input port 8a to the transmission / reception separation unit 7. do.

The transmission / reception separation unit 7 outputs the scattered pulsed light output from the input port 8a of the telescope 8 to the receiving side optical system 10.
When the receiving side optical system 10 receives the scattered pulse light from the transmission / reception separation unit 7, the scattered pulse light output from the transmission / reception separation unit 7 is accommodated in the input port 11a of the optical coupler 11 so that the entire scattered pulse light is accommodated in the input port 11a of the optical coupler 11. The beam diameter is adjusted, and the scattered pulsed light after adjusting the beam diameter is output to the input port 11a of the optical coupler 11.

The optical coupler 11 combines the scattered pulsed light output from the receiving side optical system 10 and the continuous light output from the optical distributor 3.
The optical coupler 11 outputs the combined light of the scattered pulse light and the continuous light to the light receiving unit 12. The frequency of the combined wave light is the difference frequency between the frequency of the scattered pulsed light and the frequency of the transmitted pulsed light. The difference frequency is the sum of the frequency Δf for the up-conversion by the pulse modulator 4 and the Doppler shift frequency generated by the movement of the atmosphere.
When the light receiving unit 12 receives the combined wave light from the optical coupler 11, the light receiving unit 12 converts the combined wave light into an electric signal and outputs the received signal, which is an electric signal, to the AD conversion unit 21.

Upon receiving the trigger signal output from the trigger generation circuit 33, the AD conversion unit 21 starts a process of converting the received signal output from the light receiving unit 12 from an analog signal to a digital signal, and converts the digital signal into a signal dividing unit 22. Output to.
If the range bin information output unit 26b has not yet output range bin information indicating the range bin including the distance to the measurement target, the signal division unit 22 outputs the digital signal output from the AD conversion unit 21 to the frequency domain signal output unit. Output to 24.
At this stage, since the range bin information has not yet been output from the range bin information output unit 26b, the signal division unit 22 outputs the digital signal to the frequency domain signal output unit 24.

When the frequency domain signal output unit 24 receives a digital signal from the signal dividing unit 22, the frequency domain signal output unit 24 converts the digital signal into a signal in the frequency domain by FFTing the digital signal (step ST1 in FIG. 5). A signal in the frequency domain is a signal indicating the light intensity of each of a plurality of frequencies.
The frequency domain signal output unit 24 outputs the frequency domain signal to the distance characteristic calculation unit 26a of the range bin specifying processing unit 25.

When the distance characteristic calculation unit 26a receives a signal in the frequency domain from the frequency domain signal output unit 24, the distance characteristic calculation unit 26a identifies the spectrum peak value of the range bin corresponding to each frequency from the signal in the frequency domain (step ST2 in FIG. 5).
As shown in FIG. 7A, the distance characteristic calculation unit 26a outputs the spectrum peak value of each range bin to the range bin information output unit 26b as the spectrum peak data AS_wind (L) at the time of atmospheric measurement. L is a range bin.
FIG. 7A is an explanatory diagram showing the spectrum peak data AS_HT (L) at the time of measurement of the measurement target and the spectrum peak data AS_wind (L) at the time of atmospheric measurement.

When the range bin information output unit 26b receives the spectrum peak data AS_wind (L) at the time of atmospheric measurement from the distance characteristic calculation unit 26a, the range bin information output unit 26b stores the spectrum peak data AS_wind (L) at the time of atmospheric measurement.
Further, the range bin information output unit 26b outputs a completion signal indicating that the atmospheric measurement is completed to the directivity direction control unit 34 (step ST3 in FIG. 5).
When the directivity control unit 34 receives a completion signal from the range bin information output unit 26b indicating that the atmospheric measurement is completed, the scanner 9 so that the directivity direction of the transmitted pulse light is the direction in which the measurement target exists. The control signal for controlling the above is output to the scanner 9.

The scanner 9 changes the directivity direction of the transmission pulse light according to the control signal output from the directivity direction control unit 34, and puts the transmission pulse light output from the telescope 8 into the atmosphere in the direction in which the measurement target exists. Radiate.
The transmitted pulsed light emitted from the scanner 9 is scattered by the measurement target or by the atmosphere. The transmission pulse light scattered by the measurement target or the transmission pulse light scattered by the atmosphere returns to the scanner 9 as scattered pulse light.
The scanner 9 receives the returned scattered pulse light and outputs the received scattered pulse light to the inlet / outlet 8b of the telescope 8.
When the scattered pulse light is output from the scanner 9 to the input port 8b, the telescope 8 reduces the beam diameter of the scattered pulse light and outputs the scattered pulse light after the reduced beam diameter to the transmission / reception separation unit 7.

The transmission / reception separation unit 7 outputs the scattered pulsed light output from the input port 8a of the telescope 8 to the receiving side optical system 10.
When the receiving side optical system 10 receives the scattered pulse light from the transmission / reception separation unit 7, the scattered pulse light output from the transmission / reception separation unit 7 is accommodated in the input port 11a of the optical coupler 11 so that the entire scattered pulse light is accommodated in the input port 11a of the optical coupler 11. The beam diameter is adjusted, and the scattered pulsed light after adjusting the beam diameter is output to the input port 11a of the optical coupler 11.

The optical coupler 11 combines the scattered pulsed light output from the receiving side optical system 10 and the continuous light output from the optical distributor 3.
The optical coupler 11 outputs the combined light of the scattered pulse light and the continuous light to the light receiving unit 12. The frequency of the combined wave light is the difference frequency between the frequency of the scattered pulsed light and the frequency of the transmitted pulsed light. The difference frequency is the sum of the up-converted frequency Δf by the pulse modulator 4 and the Doppler shift frequency generated by the movement of the atmosphere, or the Doppler shift frequency generated by the up-converted frequency Δf and the movement of the measurement target. It is the sum of f _DOP .
When the light receiving unit 12 receives the combined wave light from the optical coupler 11, the light receiving unit 12 converts the combined wave light into an electric signal and outputs the received signal, which is an electric signal, to the AD conversion unit 21.

The AD conversion unit 21 converts the received signal output from the light receiving unit 12 from an analog signal to a digital signal, and outputs the digital signal to the signal dividing unit 22.
If the range bin information output unit 26b has not yet output range bin information indicating the range bin including the distance to the measurement target, the signal division unit 22 outputs the digital signal output from the AD conversion unit 21 to the frequency domain signal output unit. Output to 24.
At this stage, since the range bin information has not yet been output from the range bin information output unit 26b, the signal division unit 22 outputs the digital signal to the frequency domain signal output unit 24.

When the frequency domain signal output unit 24 receives a digital signal from the signal dividing unit 22, the frequency domain signal output unit 24 converts the digital signal into a signal in the frequency domain by FFTing the digital signal (step ST4 in FIG. 5).
As shown in FIG. 4C, the signal in the frequency domain includes a component due to scattering from the sea surface to be measured and a component due to scattering from the atmosphere.
FIG. 4C is an explanatory diagram showing an example of a signal in the frequency domain output from the frequency domain signal output unit 24.
The frequency domain signal output unit 24 outputs a signal in the frequency domain to the distance characteristic calculation unit 26a.

When the distance characteristic calculation unit 26a receives a signal in the frequency domain from the frequency domain signal output unit 24, the distance characteristic calculation unit 26a identifies the spectrum peak value of the range bin corresponding to each frequency from the signal in the frequency domain (step ST5 in FIG. 5).
As shown in FIG. 7A, the distance characteristic calculation unit 26a outputs the spectrum peak value of each range bin to the range bin information output unit 26b as the spectrum peak data AS_HT (L) at the time of measurement of the measurement target.

As shown in the following equation (1), the range bin information output unit 26b contains the spectrum peak data AS_HT (L) output from the distance characteristic calculation unit 26a at the time of measurement of the measurement target and the stored spectrum at the time of atmospheric measurement. The difference ΔAS (L) from the peak data AS_wind (L) (see FIG. 7B) is calculated.
ΔAS (L) = AS_HT (L) -AS_wind (L) (1)

Even if the direction of the transmitted pulsed light at the time of atmospheric measurement and the direction of the transmitted pulsed light at the time of measurement of the measurement target are different, the components of the scattered pulsed light due to scattering from the atmosphere are almost the same.
FIG. 7B is an explanatory diagram showing the difference ΔAS (L) and the threshold value Th.
The threshold value Th may be stored in the internal memory of the range bin information output unit 26b, or may be given from the outside of the radar device shown in FIG.

The range bin information output unit 26b compares the difference ΔAS (L) with the threshold value Th, and determines whether or not there is a range bin having a difference ΔAS (L) larger than the threshold value Th.
If there is one or more range bins whose difference ΔAS (L) is larger than the threshold value Th, the range bin information output unit 26b has the largest difference ΔAS (L) among the one or more difference ΔAS (L) having a difference ΔAS (L) larger than the threshold value Th. ) Corresponding to the range bin L _max (step ST6 in FIG. 5). The range bin L _max is a range bin including the distance to the measurement target.
The range bin information output unit 26b outputs range bin information indicating the specified range bin L _max to each of the signal division unit 22 and the movement speed calculation unit 32, and outputs a completion signal indicating that the range bin identification is completed to the pulse width control unit 27. Output to.

When the pulse width control unit 27 receives a completion signal from the range bin information output unit 26b indicating that the range bin has been specified, the pulse width control unit 27 sends a control signal indicating that the pulse width is narrowed to the trigger generation circuit 33 and the signal division unit 22. Output to each.
When the trigger generation circuit 33 receives a control signal from the pulse width control unit 27 indicating that the pulse width is narrowed, the trigger generation circuit 33 controls the pulse modulation by the pulse modulator 4, and the transmission pulse light generated by the pulse modulator 4 is controlled. The pulse width of is narrower than the initial value.
After that, the transmission / reception unit 5 radiates the transmission pulse light whose pulse width is narrower than the initial value into the atmosphere, and receives the scattered light whose pulse width is narrower than the initial value. The transmission / reception unit 5 converts the combined light of the scattered pulse light and the continuous light whose pulse width is narrower than the initial value into an electric signal, and outputs the received signal, which is an electric signal, to the AD conversion unit 21.

The AD conversion unit 21 converts the received signal output from the light receiving unit 12 from an analog signal to a digital signal, and outputs the digital signal to the signal dividing unit 22.
When the signal dividing unit 22 receives the range bin information from the range bin information output unit 26b, each time the digital signal is output from the AD conversion unit 21, the range bin L _max indicated by the range bin information is selected from the output digital signals. The digital signal V _n (t) is cut out. n is a shot number of the transmission pulse light, and n = 1, 2, ..., N. The digital signal V _n (t) corresponds to the received signal related to the transmission pulsed light of one shot.
FIG. 8A is an explanatory diagram showing a digital signal V _n (t) cut out by the signal dividing unit 22.
The signal dividing unit 22 outputs the cut out digital signal V _n (t) to the complex signal generation unit 29.

Hereinafter, the process of cutting out the digital signal V _n (t) by the signal dividing unit 22 will be specifically described. Here, for simplification of the description, an example in which the shot number of the transmission pulsed light is n = 1 will be described.
As shown in the following equation (2), the signal dividing unit 22 emits the transmission pulse light from the scanner 9 of the transmission / reception unit 5 based on the range bin L _max indicated by the range bin information, and then the scanner 9 is the measurement target. The time t _max required to receive the scattered pulsed light from is calculated.
t _max = 2 × L _max / c (2)
In equation (2), c is the speed of light.
Next, as shown in the following equation (3), the signal dividing unit 22 is from the AD conversion unit 21 from the time t ₀ when the control signal indicating that the pulse width is narrowed is output from the pulse width control unit 27. The time t _L at which the digital signal of the range bin L _max is output is calculated. Since the range bin L _max has a time width of Δt, the time t _L is the time when the center of the range bin L _max is output.
t _L = t ₀ + t _max (3)
Here, for the sake of simplicity of explanation, the transmission / reception unit 5 emits the transmission pulse light after the transmission pulse light is output from the pulse modulator 4 for the time required for the pulse modulator 4 to generate the transmission pulse light. Time until the transmission / reception unit 5 receives the scattered pulse light and the time until the reception signal is output to the AD conversion unit 21 and after the reception signal is output from the transmission / reception unit 5 the AD conversion unit 21 Each of the times until the digital signal is output to the signal dividing unit 22 is ignored.
These times are ignored because they are extremely short times, but the signal dividing unit 22 may calculate the time t _L based on these times. When calculating the time t _L based on these times, these times may be added to the time t ₀ .

Next, as shown in the following equation (4), the signal dividing unit 22 calculates the start time t ₁ of the digital signal V ₁ (t) to be cut out from the digital signals.
t ₁ = t _L − Δt / 2 (4)
In the equation (4), Δt is the time width of each range bin, and is stored in the internal memory of the signal dividing unit 22, for example.
Next, as shown in the following equation (5), the signal dividing unit 22 calculates the tail time t ₂ of the digital signal V ₁ (t) to be cut out from the digital signals.
t ₂ = t _L + Δt / 2 (5)
The signal dividing unit 22 cuts out a digital signal from the start time t ₁ to the tail time t ₂ from the digital signals, and outputs the cut out digital signal V ₁ (t) to the complex signal generation unit 29.
Here, an example in which the shot number of the transmission pulse light is n = 1 is described. When the shot number of the transmission pulse light is n = 2, ..., N, the time of the pulse interval of the transmission pulse light and the time width Δt of each range bin are set to time t ₀ according to the value of n. In addition to, the digital signal V _n (t) can be cut out from the digital signal in the same manner as the digital signal V ₁ (t).

Each time the digital signal V _n (t) is output from the signal dividing unit 22, the complex signal generation unit 29 outputs the digital signal V _n as shown in the following equations (6) and (7). By performing the Hilbert conversion for (t), the digital signal V _n (t) is converted into a complex signal (step ST11 in FIG. 6).
V _{real; n} (t) = Real [Hilbert (V _n (t))] (6)
V _{imag; n} (t) = Imag [Hilbert (V _n (t))] (7)
In the equations (6) and (7), V _{real; n} (t) is the real signal in the complex signal, V _{imag; n} (t) is the imaginary signal V _imag ; n (t) in the complex signal. ), Hilbert (・) is a function that performs the Hilbert transform.

FIG. 8B is an explanatory diagram showing the real part signal V _{real; n} (t) in the complex signal and the imaginary part signal V _image; n (t) in the complex signal.
The complex signal generation unit 29 outputs the complex signal to the phase data calculation unit 30.
Since the conversion accuracy of the complex signal generation unit 29 to the complex signal is irrelevant to the pulse width of the transmission pulse light, the conversion accuracy to the complex signal does not deteriorate even if the pulse width of the transmission pulse light is narrowed.
By narrowing the pulse width of the transmitted pulse light, the spatial resolution for the measurement target is increased, so that the mixing of the scattered pulse light from the atmosphere into the range bin containing the scattered pulse light from the measurement target is reduced.

Each time the complex signal is output from the complex signal generation unit 29, the phase data calculation unit 30 has a real signal V _{real; n} (t) in the output complex signal and an imaginary part in the output complex signal. From the signal V _{image; n} (t), the phase data angle (V _{image; n} (t) / V _{real; n} (t)) of the complex signal is calculated (step ST12 in FIG. 6).
Since the process itself of calculating the phase data from the signal V _{real; n (} t) of the real part and the signal V image; n (t) of the imaginary part is a known technique, detailed description thereof will be omitted.
Next, as shown in the following equation (8), the phase data calculation unit 30 performs unwrap processing on the phase data angle (V _{imag; n} (t) / V _{real; n} (t)) of the complex signal. This converts the phase data angle (V _{imag; n} (t) / V _{real; n} (t)) into the phase data _{Sph_Ob; n} (t) having a substantially linear waveform.
S _{ph_Ob; n} (t)
= Unwrap [angle ( _{Vimag; n} (t) / V _{real; n} (t))] (8)
In equation (8), unwrap [・] is a function that performs unwrap processing.

FIG. 8C is an explanatory diagram showing phase data _{Sph_Ob; n} (t) having a substantially linear waveform.
As shown in FIG. 8C, the waveform of the phase data S _{ph_Ob; n} (t) deviates slightly from the ideal linear waveform, but is generally a linear waveform. The waveform of the phase data S _{ph_Ob; n} (t) may deviate from the linear waveform within a range where there is no practical problem, and does not have to be a strictly linear waveform.
The phase data calculation unit 30 outputs phase data _{Sph_Ob; n} (t) having a substantially linear waveform to the frequency calculation unit 31.
Since the accuracy of the phase data _{Sph_Ob; n} (t) output from the phase data calculation unit 30 is irrelevant to the pulse width of the transmission pulse light, the phase data calculation unit even if the pulse width of the transmission pulse light is narrowed. The accuracy of the phase data _{Sph_Ob; n} (t) output from 30 does not deteriorate.

The frequency calculation unit 31 fits the output phase data S _{ph_Ob; n} (t) with the linear function f (t) each time the phase data S _{ph_Ob; n} (t) is output from the phase data calculation unit 30. ..
The linear function f (t) is a linear function and is expressed as α _n · t + β _n . α _n is a coefficient indicating the slope of the linear function, and β _n is a coefficient indicating the intercept of the linear function.
The frequency calculation unit 31 sets the frequency f _{IF; n} of the received signal output from the light receiving unit 12 from the coefficient α _n indicating the slope of the fitted linear function f (t) as shown in the following equation (9). Calculate (step ST13 in FIG. 6).
f _{IF; n} = f _AD × α _n / 2π (9)
In equation (9), f _AD is the sampling rate of the AD conversion unit 21, and π is the pi.
The frequency calculation unit 31 outputs the calculated frequency _{fIF; n} of the received signal to the frequency calculation unit 31.

Hereinafter, an example of the frequency _{fIF; n} calculation process by the frequency calculation unit 31 will be specifically described.
For example, a plurality of linear functions f ₁ (t) to f _M (t) are stored in the internal memory of the frequency calculation unit 31. Alternatively, a plurality of linear functions f ₁ (t) to f _M (t) are given to the frequency calculation unit 31 from the outside of the radar device shown in FIG. M is an integer of 2 or more.
The frequency calculation unit 31 inputs the phase data _{Sph_Ob; n} (t) at t = t ₁ to t ₂ and the plurality of linear functions f ₁ (t) to f _M (t) at t = t ₁ to t ₂ . Compare. The linear function f _m (t) (m = 1, ..., M) is a linear function and is expressed as α _m · t + β _m . α _m is a coefficient indicating the slope of the linear function, and β _m is a coefficient indicating the intercept of the linear function.
The frequency calculation unit 31 searches for a linear function f _m (t) that is the closest to the phase data _{Sph_Ob; n} (t) from among a plurality of linear functions f ₁ (t) to f _M (t). .. Since the process itself for searching the linear function fm (t), which is the closest to the phase data _{Sph_Ob; n (} t), is a known technique, detailed description thereof will be omitted.
The frequency calculation unit 31 calculates the frequency f _{IF; n} of the received signal by substituting the coefficient α _m indicating the slope of the searched linear function f _m (t) into the equation (9) as α _n .

The frequency calculation unit 31 calculates the frequency f _{IF; n} of the output received signal each time the phase data S _{ph_Ob; n} (t) is output from the phase data calculation unit 30, and the calculated frequency f _{IF; n.} To save.
When the frequency calculation unit 31 stores N frequencies f _{IF ; 1} to f _{IF ; N} , the probability density of N frequencies f IF; 1 to f IF; N is shown in the following equation (10). The distribution p (f _IF ) is generated, and the probability density distribution p (f _IF ) is output to the movement speed calculation unit 32 (step ST14 in FIG. 6).
p (f _IF ) = histogram (f _{IF; n} , n = 1 to N) (10)

In equation (10), histogram (.) Is a function that generates a probability density distribution.
FIG. 8D is an explanatory diagram showing the probability density distribution p (f _IF ) generated by the frequency calculation unit 31.
Since the generation accuracy of the probability density distribution p (f _IF ) in the frequency calculation unit 31 is irrelevant to the pulse width of the transmission pulse light, the probability density distribution p (f _IF ) even if the pulse width of the transmission pulse light is narrowed. The generation accuracy of is not deteriorated.

Upon receiving the probability density distribution p (f _IF ) from the frequency calculation unit 31, the moving speed calculation unit 32 identifies the peak frequency f _peak of the probability density distribution p (f _IF ).
Since the process itself for specifying the peak frequency f _peak of the probability density distribution p (f _IF ) is a known technique, detailed description thereof will be omitted, but for example, the center of gravity calculation for the probability density distribution p (f _IF ) is performed. Therefore, the peak frequency f _peak can be specified.
Next, as shown in the following equation (11), the movement speed calculation unit 32 calculates the Doppler shift frequency f _DOP generated by the movement of the measurement target from the peak frequency f _peak (step ST15 in FIG. 6). ..
f _DOP = f _peak -f _{IF; STOP} (11)
In the equation (11), _{fIF; STOP} is the frequency of the received signal when the measurement target is stopped, and is stored in, for example, the internal memory of the moving speed calculation unit 32.

Next, the moving speed calculation unit 32 calculates the moving speed V of the measurement target from the Doppler shift frequency f _DOP as shown in the following equation (12) (step ST16 in FIG. 6).
V = λ ・ f _DOP / 2 (12)
In equation (12), λ is the wavelength of continuous light oscillated by the light source 2.
The moving speed calculation unit 32 outputs each of the calculated moving speed V of the measurement target and the range bin indicated by the range bin information output from the range bin information output unit 26b to the outside. Alternatively, the moving speed calculation unit 32 displays each of the calculated moving speed V of the measurement target and the range bin indicated by the range bin information on a display or the like (not shown).
Since the calculation accuracy of the movement speed V in the movement speed calculation unit 32 is irrelevant to the pulse width of the transmission pulse light, the calculation accuracy of the movement speed V does not deteriorate even if the pulse width of the transmission pulse light becomes narrow.
In addition, by narrowing the pulse width of the transmitted pulse light, the spatial resolution for the measurement target is increased, and the mixing of the scattered pulse light from the atmosphere into the range bin containing the scattered pulse light from the measurement target is reduced. , The calculation accuracy of the moving speed V is improved.

In the above-described first embodiment, the transmitted signal generated by pulse-modulating the continuous light is the scattered pulse light that is scattered by the measurement target, and the received signal obtained by the heterodyne detection of the continuous light. Phase data of a complex signal from a complex signal generation unit 29 that converts to a complex signal and outputs a complex signal, a real part signal in the complex signal output from the complex signal generation unit 29, and an imaginary part signal in the complex signal. The frequency calculation unit 30 that calculates the frequency of the received signal based on the phase data calculated by the phase data calculation unit 30, and the frequency calculation unit 31 that calculates the frequency of the received signal. Therefore, the signal processing device 20 is configured to include a movement speed calculation unit 32 that calculates the Doppler shift frequency generated by the movement of the measurement target and calculates the movement speed of the measurement target from the Doppler shift frequency. Therefore, the signal processing device 20 can prevent erroneous calculation of the moving speed in the measurement target even when the difference between the light reflectance in the measurement target and the light reflectance in the atmosphere is small.

Further, in the first embodiment, the received signal obtained by the transmission / reception unit 5 is converted into a signal in the frequency domain and output from the frequency domain signal output unit 24 and the frequency domain signal output unit 24 to output the signal in the frequency domain. The range bin specified by the range bin specifying processing unit 25 from the received signals obtained by the range bin specifying processing unit 25 that specifies the range bin including the distance to the measurement target and the transmission / reception unit 5 based on the signal in the frequency domain. The signal processing device 20 is configured to include a signal dividing unit 22 that cuts out the received signal of the above and outputs the cut out received signal to the complex signal generation unit 29. Therefore, the signal processing device 20 can shorten the time required to calculate the moving speed of the measurement target as compared with the case where all the received signals output from the transmission / reception unit 5 are output to the complex signal generation unit 29. ..
If it is not necessary to shorten the time required to calculate the moving speed of the measurement target, all the received signals output from the transmission / reception unit 5 may be output to the complex signal generation unit 29. good.

In the radar device shown in FIG. 1, the frequency calculation unit 31 linearly outputs the output phase data S _{ph_Ob} ; n (t) each time the phase data S _{ph_Ob; n} (t) is output from the phase data calculation unit 30. The frequency f _{IF; n} of the received signal is calculated from the coefficient α _n indicating the inclination of the fitted linear function f (t) by fitting with the function f (t).
However, this is only an example, and the frequency calculation unit 31 obtains the coefficient α _n from the amount of change between the phase data at different times in the phase data _{Sph_Ob; n} (t), and obtains the coefficient α _n from the coefficient α n of the received signal. The frequency f _{IF; n} may be calculated.
The frequency calculation unit 31 obtains, for example, the amount of change between the phase data S _{ph_Ob; n} (t ₁₁ ) and the phase data S _{ph_Ob; n} (t ₁₂ ), and determines the amount of change for the time (t ₁₂ −t ₁₁ ). The coefficient α _n may be obtained by dividing by. Further, the frequency calculation unit 31 obtains, for example, the amount of change between the phase data S _{ph_Ob; n} (t ₁₁ ) and the phase data S _{ph_Ob; n} (t ₁₄ ), and determines the amount of change for the time (t ₁₄ −t). The coefficient α _n may be obtained by dividing by ₁₁ ).

In the radar device shown in FIG. 1, the transmission / reception separation unit 7 outputs transmission pulse light to the inlet / outlet 8a of the telescope 8. However, this is only an example, and an optical amplifier for amplifying the transmission pulse light output from the transmission / reception separation unit 7 is provided so that the optical amplifier outputs the amplified transmission pulse light to the inlet / outlet 8a of the telescope 8. You may do it.

Embodiment 2.
In the radar device shown in FIG. 1, the transmission / reception unit 5 includes one telescope 8 and one scanner 9, and the directivity direction control unit 34 controls the scanner 9.
In the second embodiment, a radar device in which the transmission / reception unit 5 includes one optical switch 61 and two telescopes 8-1 and 8-2 will be described.

FIG. 9 is a configuration diagram showing a radar device including the signal processing device 20 according to the second embodiment.
In FIG. 9, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts, and thus the description thereof will be omitted.
After receiving the trigger signal from the trigger generation circuit 33, the optical switch 61 receives the transmission pulse output from the transmission / reception separation unit 7 until the range bin information output unit 26b receives the completion signal indicating that the atmospheric measurement is completed. The light is output to the inlet / outlet 8-1a of the telescope 8-1, and the scattered pulse light output from the inlet / outlet 8-1a of the telescope 8-1 is output to the receiving optical system 10.
When the optical switch 61 receives a completion signal from the range bin information output unit 26b indicating that the atmospheric measurement is completed, the optical switch 61 transmits the transmission pulse light output from the transmission / reception separation unit 7 to the inlet / outlet 8-2a of the telescope 8-2. It is output, and the scattered pulse light output from the inlet / outlet 8-2a of the telescope 8-2 is output to the receiving side optical system 10.

The telescope 8-1 includes inlets and outlets 8-1a and 8-1b.
The telescope 8-1 is installed so that the directivity direction of the transmitted pulse light is directed to the direction in which the measurement target does not exist.
When the transmission pulse light is output from the optical switch 61 to the inlet / outlet 8-1a, the telescope 8-1 expands the beam diameter of the transmission pulse light and transmits the transmission pulse light after the beam diameter expansion to the inlet / outlet 8- It radiates from 1b into the atmosphere in the direction where the measurement target does not exist.
The transmitted pulsed light emitted from the inlet / outlet 8-1b of the telescope 8-1 is scattered by the atmosphere. The transmitted pulsed light scattered by the atmosphere returns to the inlet / outlet 8-1b of the telescope 8-1 as the scattered pulsed light.
The telescope 8-1 receives the returned scattered pulse light, reduces the beam diameter of the scattered pulse light, and outputs the scattered pulse light after the beam diameter reduction from the inlet / outlet 8-1a to the optical switch 61.

The telescope 8-2 includes inlets and outlets 8-2a and 8-2b.
The telescope 8-2 is installed so that the directivity direction of the transmitted pulse light faces the direction in which the measurement target exists.
When the transmission pulse light is output from the optical switch 61 to the inlet / outlet 8-2a, the telescope 8-2 expands the beam diameter of the transmission pulse light and transmits the transmission pulse light after the beam diameter expansion to the inlet / outlet 8-2. It radiates from 2b into the atmosphere in the direction in which the measurement target exists.
The transmitted pulsed light emitted from the inlet / outlet 8-2b of the telescope 8-2 is scattered by the measurement target or by the atmosphere. The transmission pulse light scattered by the measurement target or the transmission pulse light scattered by the atmosphere returns to the inlet / outlet 8-2b of the telescope 8-2 as the scattered pulse light.
The telescope 8-2 receives the returned scattered pulse light, reduces the beam diameter of the scattered pulse light, and outputs the scattered pulse light after the beam diameter reduction from the inlet / outlet 8-2a to the optical switch 61.

In the radar device shown in FIG. 9, the transmission / reception unit 5 includes one optical switch 61 and two telescopes 8-1 and 8-2, and does not include the scanner 9 and the directivity control unit 34. It is different from the radar device shown in FIG.
The radar device shown in FIG. 9 differs from the radar device shown in FIG. 1 in that the trigger generation circuit 33 outputs the trigger signal to the optical switch 61 instead of outputting the trigger signal to the directional control unit 34.
In the radar device shown in FIG. 9, the range bin information output unit 26b outputs the completion signal to the optical switch 61 instead of outputting the completion signal indicating that the atmospheric measurement is completed to the directional control unit 34. It is different from the radar device shown in FIG.
In other respects, the operation of the radar device shown in FIG. 9 and the operation of the radar device shown in FIG. 1 are the same.
Since the radar device shown in FIG. 9 does not require the scanner 9 and the directivity direction control unit 34, mechanical scanning of the transmitted pulse light becomes unnecessary.

It should be noted that, within the scope of the present invention, any combination of embodiments can be freely combined, any component of each embodiment can be modified, or any component can be omitted in each embodiment. ..

The present invention is suitable for a signal processing device, a signal processing method, and a radar device for calculating the moving speed of a measurement target.

1 Transmission pulse light generator, 2 Light source, 3 Optical distributor, 4 Pulse modulator, 5 Transmission / reception unit, 6 Transmission side optical system, 7 Transmission / reception separation unit, 8,8-1,8-2 Telescope, 8a, 8b , 8-1a, 8-2a, 8-1b, 8-2b inlet / outlet, 9 scanner, 10 receiving side optical system, 11 optical coupler, 11a input port, 12 light receiving unit, 20 signal processing device, 21 AD conversion unit, 22 Signal division unit, 23 Range bin identification unit, 24 Frequency region signal output unit, 25 Range bin specification processing unit, 26a Distance characteristic calculation unit, 26b Range bin information output unit, 27 Pulse width control unit, 28 Speed calculation unit, 29 Complex signal generation Unit, 30 phase data calculation unit, 31 frequency calculation unit, 32 movement speed calculation unit, 33 trigger generation circuit, 34 directional control unit, 41 signal division circuit, 42 frequency region signal output circuit, 43 distance characteristic calculation circuit, 44 range bin. Information output circuit, 45 pulse width control circuit, 46 complex signal generation circuit, 47 phase data calculation circuit, 48 frequency calculation circuit, 49 moving speed calculation circuit, 51 memory, 52 processor, 61 optical switch.

Claims (9)

The transmitted pulse light generated by pulse-modulating the continuous light is the light scattered by the measurement target, and the received signal obtained by heterodyne detection with the continuous light is converted into a complex signal. A complex signal generator that outputs a complex signal,
A phase data calculation unit that calculates the phase data of the complex signal from the real part signal of the complex signal and the imaginary part signal of the complex signal output from the complex signal generation unit.
A frequency calculation unit that calculates the frequency of the received signal based on the phase data calculated by the phase data calculation unit, and a frequency calculation unit.
From the frequency of the received signal calculated by the frequency calculation unit, the Doppler shift frequency generated by the movement of the measurement target is calculated, and the movement speed of the measurement target is calculated from the Doppler shift frequency. When
A frequency domain signal output unit that converts the received signal into a signal in the frequency domain and outputs the signal in the frequency domain.
A range bin specifying processing unit that specifies a range bin including a distance from the measurement target based on a signal in the frequency domain output from the frequency domain signal output unit.
A signal dividing unit that cuts out the received signal of the range bin specified by the range bin specifying processing unit from the received signals and outputs the cut out received signal to the complex signal generation unit.
A signal processing device equipped with. The complex signal generation unit combines the scattered pulse light, which is the light scattered by the measurement target for the transmission pulse light generated by pulse-modulating the continuous light, and the received signal obtained by heterodyne detection with the continuous light. Convert to a signal, output the complex signal,
The phase data calculation unit calculates the phase data of the complex signal from the real part signal in the complex signal and the imaginary part signal in the complex signal output from the complex signal generation unit.
The frequency calculation unit calculates the frequency of the received signal based on the phase data calculated by the phase data calculation unit.
The moving speed calculation unit calculates the Doppler shift frequency generated by the movement of the measurement target from the frequency of the received signal calculated by the frequency calculation unit, and calculates the movement speed of the measurement target from the Doppler shift frequency. Calculate and
The frequency domain signal output unit converts the received signal into a signal in the frequency domain and outputs the signal in the frequency domain.
The range bin specifying processing unit identifies the range bin including the distance to the measurement target based on the signal in the frequency domain output from the frequency domain signal output unit.
The signal dividing unit cuts out the received signal of the range bin specified by the range bin specifying processing unit from the received signals, and outputs the cut out received signal to the complex signal generation unit.
Signal processing method. A transmission pulse light generator that generates transmission pulse light by pulse-modulating continuous light,
After radiating the transmission pulse light generated by the transmission pulse light generation unit, the scattered pulse light which is the transmission pulse light scattered by the measurement target is received, and the heterodyne detection of the scattered pulse light and the continuous light is received. And the transmitter / receiver that obtains the received signal by
A complex signal generation unit that converts the received signal obtained by the transmission / reception unit into a complex signal and outputs the complex signal.
A phase data calculation unit that calculates the phase data of the complex signal from the real part signal of the complex signal and the imaginary part signal of the complex signal output from the complex signal generation unit.
A frequency calculation unit that calculates the frequency of the received signal based on the phase data calculated by the phase data calculation unit, and a frequency calculation unit.
From the frequency of the received signal calculated by the frequency calculation unit, the Doppler shift frequency generated by the movement of the measurement target is calculated, and the movement speed of the measurement target is calculated from the Doppler shift frequency. When
A frequency domain signal output unit that converts the received signal into a signal in the frequency domain and outputs the signal in the frequency domain.
A range bin specifying processing unit that specifies a range bin including a distance from the measurement target based on a signal in the frequency domain output from the frequency domain signal output unit.
A signal dividing unit that cuts out the received signal of the range bin specified by the range bin specifying processing unit from the received signals and outputs the cut out received signal to the complex signal generation unit.
Radar device equipped with. Each time the received signal is obtained by the transmission / reception unit, the complex signal generation unit converts the obtained received signal into the complex signal and outputs the complex signal.
Each time the complex signal is output from the complex signal generation unit, the phase data calculation unit uses the real part signal of the output complex signal and the imaginary part signal of the output complex signal. The phase data of the output complex signal is calculated, and the phase data is calculated.
The frequency calculation unit calculates the frequency of the obtained received signal based on the calculated phase data each time the phase data calculation unit calculates the phase data, and the calculated frequencies are plurality of. Generates a probability density distribution of
The moving speed calculation unit calculates the Doppler shift frequency from the peak frequency of the probability density distribution generated by the frequency calculation unit .
The radar device according to claim 3 . The phase data calculation unit converts the phase data into linear waveform phase data.
The frequency calculation unit calculates the frequency of the received signal based on the slope of the phase data of the linear waveform .
The radar device according to claim 3 . The frequency domain signal output unit that converts the received signal obtained by the transmission / reception unit into a signal in the frequency domain and outputs the signal in the frequency domain.
Based on the frequency domain signal output from the frequency domain signal output unit, the range bin specifying processing unit that specifies the range bin including the distance to the measurement target, and the range bin specifying processing unit.
From the received signals obtained by the transmitting / receiving unit, a signal dividing unit that cuts out the received signal of the range bin specified by the range bin specifying processing unit and outputs the cut out received signal to the complex signal generation unit . Prepared
The radar device according to claim 3 . After the range bin is specified by the range bin specifying processing unit, a pulse width control unit that controls the transmission pulse light generation unit is provided so that the pulse width of the transmission pulse light generated by the transmission pulse light generation unit is narrowed. Prepared
The radar device according to claim 6 . A directivity control unit for controlling the directivity of the transmission pulse light radiated from the transmission / reception unit is provided .
The radar device according to claim 3 . The transmission / reception unit includes a plurality of telescopes that radiate the transmission pulse light generated by the transmission pulse light generation unit in different directions .
The radar device according to claim 3 .

Images