WO2021214960A1 - Signal generation device, signal generation method, and signal generation program - Google Patents

Signal generation device, signal generation method, and signal generation program Download PDF

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Publication number
WO2021214960A1
WO2021214960A1 PCT/JP2020/017602 JP2020017602W WO2021214960A1 WO 2021214960 A1 WO2021214960 A1 WO 2021214960A1 JP 2020017602 W JP2020017602 W JP 2020017602W WO 2021214960 A1 WO2021214960 A1 WO 2021214960A1
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Prior art keywords
frequency
time response
pulse
signal generation
linear
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PCT/JP2020/017602
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French (fr)
Japanese (ja)
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智也 山岡
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三菱電機株式会社
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Priority to PCT/JP2020/017602 priority Critical patent/WO2021214960A1/en
Publication of WO2021214960A1 publication Critical patent/WO2021214960A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G01S13/26—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
    • G01S13/28—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses

Definitions

  • the present disclosure relates to a signal generator, a signal generation method, and a signal generation program that generate a non-linear chirped pulse.
  • a radar device that uses a chirped pulse as a radar signal. If the side lobe of the chirped pulse can be reduced, the target detection performance in the radar device can be improved.
  • a chirped pulse with reduced side lobes there is a non-linear chirped pulse in which the frequency power distribution is biased.
  • the non-linear chirped pulse needs to be sampled at equal time intervals in practical use. In order to generate a nonlinear chirped pulse sampled at equal time intervals, it is necessary to determine the time response of the phase in the nonlinear chirped pulse.
  • Non-Patent Document 1 discloses a method of approximating the time response of a phase in a nonlinear chirped pulse by a polynomial having a Taylor weight.
  • Non-Patent Document 1 since the time response of the phase in the nonlinear charp pulse is approximated by a polynomial, an error is included in the time response of the phase. There is a problem that the signal waveform of the nonlinear chirped pulse is deteriorated due to the inclusion of an error in the time response of the phase.
  • the present disclosure has been made to solve the above-mentioned problems, and is a signal generator and a signal capable of preventing deterioration of the signal waveform of a non-linear chap pulse due to an error in the time response of the phase.
  • the purpose is to obtain a generation method and a signal generation program.
  • the signal generator includes a time response calculation unit and a time response calculation unit that calculate the time response of the frequency in the non-linear chirp pulse by using the power characteristic of the frequency in the non-linear chirp pulse having a bias in the power distribution of the frequency. Using the time response of the frequency calculated by To prepare.
  • FIG. 5 is a hardware configuration diagram of a computer when the signal generator 1 is realized by software, firmware, or the like. It is a flowchart which shows the signal generation method which is the processing procedure of the signal generation apparatus 1 which concerns on Embodiment 1.
  • FIG. It is explanatory drawing which shows the time frequency characteristic of the radar signal s (m) generated by the signal generation unit 13. It is explanatory drawing which shows the electric power characteristic on the frequency in the radar signal s (m) generated by the signal generation unit 13.
  • FIGS. 8A and 8B are explanatory diagram showing an example of a window function W (f (m)) having a single peak shape.
  • FIGS. 9A and 9B is an explanatory diagram showing an example of a window function W (f (m)) having a compound peak shape.
  • FIG. It is a hardware block diagram which shows the hardware of the signal generation apparatus 1 which concerns on Embodiment 2.
  • FIG. It is explanatory drawing which shows an example of the function R (f). It is explanatory drawing which shows the time ⁇ T n required for the frequency transition, and the frequency change amount ⁇ F n.
  • FIG. 1 is a configuration diagram showing a radar system including the signal generation device 1 according to the first embodiment.
  • FIG. 2 is a hardware configuration diagram showing the hardware of the signal generation device 1 according to the first embodiment.
  • the radar system includes a signal generation device 1, a storage unit 2, a radar signal processing unit 3, a radar unit 4, and a display unit 5.
  • the signal generation device 1 generates a non-linear chirped pulse and outputs the non-linear chirped pulse as a radar signal to the storage unit 2.
  • the storage unit 2 is realized by, for example, a storage processing circuit.
  • the storage unit 2 stores each of the window function, the radar signal generated by the signal generation device 1, and the display data generated by the radar signal processing unit 3.
  • the storage processing circuit includes, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Flexible Memory), an EEPROM (Electrically Flexible Memory), or the like.
  • a semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versaille Disc) is applicable.
  • the radar signal processing unit 3 outputs the radar signal stored in the storage unit 2 to the radar unit 4, and acquires the received signal output from the radar unit 4.
  • the radar signal processing unit 3 uses each of the radar signal and the received signal to perform target detection processing, synthetic aperture radar image generation processing, and the like.
  • the radar signal processing unit 3 generates display data for displaying the target detection processing result or display data for displaying the synthetic aperture radar image, and outputs the generated display data to the storage unit 2.
  • the radar unit 4 radiates radio waves related to the radar signal output from the radar signal processing unit 3 into space, and receives the radio waves reflected by the target.
  • the radar unit 4 outputs a radio wave reception signal to the radar signal processing unit 3.
  • the display unit 5 includes, for example, a liquid crystal display.
  • the display unit 5 displays the target detection processing result or the synthetic aperture radar image on the liquid crystal display according to the display data stored in the storage unit 2.
  • the signal generation device 1 includes an initial value setting unit 11, a time response calculation unit 12, and a signal generation unit 13.
  • the initial value setting unit 11 is realized by, for example, the initial value setting circuit 31 shown in FIG.
  • the internal memory of the initial value setting unit 11 stores each of the frequency bandwidth B of the non-linear charp pulse, the pulse time width T of the non-linear charp pulse, and the oversampling rate ⁇ as design specifications.
  • the initial value setting unit 11 sets the sampling interval Dt of the nonlinear chirped pulse from the frequency bandwidth B and the oversampling rate ⁇ .
  • the initial value setting unit 11 sets a provisional chirp rate ⁇ 0 from the frequency bandwidth B and the pulse time width T.
  • the initial value setting unit 11 outputs each of the sampling interval Dt and the provisional chirp rate ⁇ 0 to the time response calculation unit 12.
  • the internal memory of the initial value setting unit 11 stores each of the frequency bandwidth B, the pulse time width T, and the oversampling rate ⁇ .
  • each of the frequency bandwidth B, the pulse time width T, and the oversampling rate ⁇ may be given from the outside of the signal generation device 1.
  • the time response calculation unit 12 is realized by, for example, the time response calculation circuit 32 shown in FIG.
  • the time response calculation unit 12 calculates the frequency f (m) at the sampling time m ⁇ Dt as the time response of the frequency in the nonlinear charp pulse by using the power characteristic of the frequency in the nonlinear charp pulse.
  • m is an integer within the range of M 0 ⁇ m ⁇ M 1.
  • M 0 and M 1 is an integer. That is, the time response calculation unit 12 acquires each of the sampling interval Dt output from the initial value setting unit 11 and the provisional charp rate ⁇ 0 , and is stored by the window function holding unit 21 of the storage unit 2. W (f (m)) is acquired.
  • the window function W (f (m)) shows the power characteristic of the frequency f (m) in the nonlinear chirped pulse in which the power distribution of the frequency is biased. Then, the time response calculation unit 12 uses each of the provisional chirp rate ⁇ 0 and the window function W (f (m)) to determine the amount of change Df (m) of the frequency changing during the sampling interval Dt. calculate. Then, the time response calculation unit 12 calculates the frequency f (m) at the sampling time m ⁇ Dt as the time response of the frequency in the non-linear chap pulse from the frequency change amount Df (m). The time response calculation unit 12 outputs each of the frequency f (m) and the sampling interval Dt at the sampling time m ⁇ Dt to the signal generation unit 13.
  • the signal generation unit 13 is realized by, for example, the signal generation circuit 33 shown in FIG.
  • the signal generation unit 13 calculates the time response p (m) of the phase in the nonlinear charp pulse by using the time response of the frequency calculated by the time response calculation unit 12 and the sampling interval Dt of the nonlinear charp pulse.
  • the phase time response p (m) is calculated for each sampling time m ⁇ Dt.
  • the signal generation unit 13 generates a non-linear chirped pulse having a phase time response p (m) as a radar signal s (m).
  • the signal generation unit 13 outputs the generated nonlinear chirped pulse as a radar signal s (m) to the radar signal holding unit 22 of the storage unit 2.
  • the storage unit 2 includes a window function holding unit 21, a radar signal holding unit 22, and a display data holding unit 23.
  • the window function holding unit 21 stores the window function W (f).
  • the radar signal holding unit 22 stores the radar signal s (m) generated by the signal generating unit 13.
  • the display data holding unit 23 stores the display data generated by the radar signal processing unit 3.
  • each of the initial value setting unit 11, the time response calculation unit 12, and the signal generation unit 13, which are the components of the signal generation device 1, is realized by dedicated hardware as shown in FIG. doing. That is, it is assumed that the signal generation device 1 is realized by the initial value setting circuit 31, the time response calculation circuit 32, and the signal generation circuit 33.
  • Each of the initial value setting circuit 31, the time response calculation circuit 32, and the signal generation circuit 33 includes, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), and an FPGA (FPGA). Field-Programmable Gate Array) or a combination of these is applicable.
  • the components of the signal generator 1 are not limited to those realized by dedicated hardware, but the signal generator 1 is realized by software, firmware, or a combination of software and firmware. It is also good.
  • the software or firmware is stored as a program in the memory of the computer.
  • a computer means hardware that executes 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 the signal generation device 1 is realized by software, firmware, or the like.
  • a program for causing a computer to execute each processing procedure in the initial value setting unit 11, the time response calculation unit 12, and the signal generation unit 13 is stored in the memory 41. Will be done.
  • the processor 42 of the computer executes the program stored in the memory 41.
  • FIG. 2 shows an example in which each of the components of the signal generation device 1 is realized by dedicated hardware
  • FIG. 3 shows an example in which the signal generation device 1 is realized by software, firmware, or the like. ..
  • this is only an example, and some components in the signal generation device 1 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, or the like.
  • FIG. 4 is a flowchart showing a signal generation method which is a processing procedure of the signal generation device 1 according to the first embodiment.
  • the initial value setting unit 11 sets the sampling interval Dt of the nonlinear chirped pulse from the frequency bandwidth B of the nonlinear chirped pulse and the oversampling rate ⁇ (step of FIG. 4). ST1). As shown in the following equation (2), the initial value setting unit 11 sets a provisional chirp rate ⁇ 0 from the frequency bandwidth B of the nonlinear chirp pulse and the pulse time width T of the nonlinear chirp pulse (FIG. Step 4 ST1). The initial value setting unit 11 outputs each of the sampling interval Dt and the provisional chirp rate ⁇ 0 to the time response calculation unit 12.
  • the time response calculation unit 12 acquires each of the sampling interval Dt output from the initial value setting unit 11 and the provisional charp rate ⁇ 0 , and the window function W (f (m)) stored by the window function holding unit 21. ) To get.
  • the window function W (f (m)) shows the power characteristic of the frequency f (m) in the nonlinear chirped pulse in which the power distribution of the frequency is biased.
  • the signal generator 1 shown in FIG. 1 is premised on an equivalent low frequency system in which the center frequency of the frequency f (m) is 0 [Hz].
  • the band of the frequency f (m) is ⁇ B / 2 ⁇ f (m) ⁇ B / 2.
  • the time response calculation unit 12 changes during the sampling interval Dt using each of the provisional chirp rate ⁇ 0 and the window function W (f (m)).
  • the amount of change in frequency Df (m) is calculated (step ST2 in FIG. 4).
  • Wave is the average value of the window function W (f (m)) in the band of ⁇ B / 2 ⁇ f (m) ⁇ B / 2.
  • the time response calculation unit 12 calculates the frequency f (m) at the sampling time m ⁇ Dt as the time response of the frequency in the nonlinear chap pulse from the frequency change amount Df (m) (step ST3 in FIG. 4).
  • the time response calculation unit 12 outputs each of the frequency f (m) and the sampling interval Dt at the sampling time m ⁇ Dt to the signal generation unit 13.
  • the calculation process of the frequency f (m) by the time response calculation unit 12 will be specifically described.
  • the time response calculation unit 12 calculates the frequency f (0). Since the signal generator 1 shown in FIG. 1 is premised on the fact that the center frequency of the frequency f (m) is an equivalent low frequency system of 0 [Hz], the frequency f (0) is expressed by the following equation (4). As shown in, it is 0.
  • the time response calculation unit 12 calculates all frequencies greater than 0 and B / 2 or less as frequencies f (m) in the positive frequency domain. That is, the time response calculation unit 12 repeatedly calculates the frequency f (m) at the sampling time m ⁇ Dt, as shown in the following equation (5).
  • the frequency f (m) at the sampling time m ⁇ Dt, as shown in the following equation (5).
  • f (m + 1) exceeds the B / 2
  • f (m + 1) does not exceed B / 2 do.
  • the time response calculation unit 12 calculates all frequencies smaller than 0 and greater than or equal to ⁇ B / 2 as the frequency f (m) in the negative frequency region. That is, the time response calculation unit 12 repeatedly calculates the frequency f (m) at the sampling time m ⁇ Dt, as shown in the following equation (7).
  • f (m-1) is less than ⁇ B / 2
  • f (m-1) is ⁇ B / 2. It shall not be less than.
  • the time response calculation unit 12 outputs each of the frequency f (m) and the sampling interval Dt at the sampling time m ⁇ Dt calculated repeatedly to the signal generation unit 13.
  • the frequency f (m) at the sampling time m ⁇ Dt repeatedly calculated by the time response calculation unit 12 is a frequency of a plurality of times different by the sampling interval Dt. Therefore, the frequency f (m) at the sampling time m ⁇ Dt repeatedly calculated by the time response calculation unit 12 is the window function W (f (m)) even though the sampling is performed at equal time intervals. It correlates with the amount of change Df (m) weighted by the reciprocal.
  • the time response calculation unit 12 calculates the frequency f (m) in the positive frequency domain by the equation (5), and the frequency f (m) in the negative frequency domain is calculated by the equation (7). ) Is calculated.
  • W (f (m)) W ( ⁇ f (m)
  • the frequency f (m) in the positive frequency domain Is calculated by the equation (5), and then the frequency f (m) in the negative frequency region may be given as shown in the following equation (9).
  • the f ( ⁇ m) on the right side of the equation (9) is obtained by replacing m at the frequency f (m) in the positive frequency domain with ⁇ m.
  • the signal generation unit 13 acquires the frequency f (m) and the sampling interval Dt at the sampling time m ⁇ Dt output from the time response calculation unit 12.
  • the signal generation unit 13 calculates the time response p (m) of the phase in the non-linear chap pulse by using the frequency f (m) at the sampling time m ⁇ Dt and the sampling interval Dt (step ST4 in FIG. 4).
  • the phase time response p (m) is a plurality of time phases that differ by the sampling interval Dt.
  • the process of calculating the phase time response p (m) by the signal generation unit 13 will be specifically described.
  • the signal generation unit 13 assumes that m changes by 1 in the range of M 0 + 1 ⁇ m ⁇ M 1, and as shown in the following equations (12) and (13), the amount of phase change.
  • D p (m) and the phase time response p (m) is calculated.
  • the signal generation unit 13 assumes that m changes by 1 in the range of M 0 ⁇ m ⁇ M 1, and as shown in the following equation (14), the phase of the radar signal s (m) is changed.
  • a non-linear chirped pulse having a time response p (m) is generated (step ST5 in FIG. 4).
  • the signal generation unit 13 outputs the generated nonlinear chirped pulse as a radar signal s (m) to the radar signal holding unit 22 of the storage unit 2.
  • FIG. 5 is an explanatory diagram showing the time-frequency characteristics of the radar signal s (m) generated by the signal generation unit 13.
  • the horizontal axis represents time and the vertical axis represents frequency.
  • the thick line shows the time-frequency characteristics of the radar signal s (m) when the Hamming window is used as the window function W (f (m)).
  • the thin line shows the time-frequency characteristics of the linear chirp.
  • FIG. 6 is an explanatory diagram showing the power characteristics on the frequency of the radar signal s (m) generated by the signal generation unit 13.
  • the horizontal axis represents the frequency and the vertical axis represents the normalized amplitude after pulse compression. The normalized amplitude is equivalent to the normalized power before pulse compression.
  • the thick line shows the power characteristic on the frequency in the radar signal s (m) shown by the thick line in FIG.
  • the thin line is the Hamming window.
  • the radar signal s (m) when the Hamming window is used as the window function W (f (m)) obtains a signal component similar to that of the humming window on the frequency.
  • FIG. 7 is an explanatory diagram showing a radar signal s (m)'after pulse compression.
  • the horizontal axis represents the range and the vertical axis represents the normalized power.
  • the thick line indicates the radar signal s (m)'which is the signal after pulse compression of the radar signal s (m) shown by the thick line in FIG. 5, and the thin line is the signal after pulse compression of the linear chirp provided with the Hamming window. Is shown.
  • the radar signal s (m)'after pulse compression has substantially the same characteristics as the signal after pulse compression of a linear chirp provided with a Hamming window. That is, the radar signal s (m)'after pulse compression has a sidelobe reduction effect similar to the signal after pulse compression of the linear chirp provided with the Hamming window.
  • the shape of the power distribution on the frequency in the radar signal s (m) generated by the signal generation unit 13 has the same shape as the window function W (f (m)). Therefore, if the shape indicated by the window function W (f (m)) is, for example, a single peak type as shown in FIG. 8A or FIG. 8B, the shape of the power distribution on the frequency in the radar signal s (m) is , Becomes a single peak type. If the shape indicated by the window function W (f (m)) is, for example, a double peak type as shown in FIG. 9A or FIG. 9B, the shape of the power distribution on the frequency in the radar signal s (m) is double. It becomes a peak type.
  • FIGS. 9A and 9B is an explanatory diagram showing an example of a window function W (f (m)) having a single peak shape.
  • FIGS. 9A and 9B is an explanatory diagram showing an example of a window function W (f (m)) having a compound peak shape.
  • the time response calculation unit 12 and the time response calculation unit 12 that calculate the time response of the frequency in the non-linear charp pulse by using the power characteristic of the frequency in the non-linear chirp pulse having a bias in the power distribution of the frequency.
  • the signal generation unit 13 that calculates the time response of the phase in the non-linear charp pulse and generates the non-linear chap pulse having the time response of the phase.
  • the signal generation device 1 is configured to include the above. Therefore, the signal generation device 1 can prevent deterioration of the signal waveform of the nonlinear chirped pulse due to the inclusion of an error in the time response of the phase.
  • the time response calculation unit 14 calculates the rate of change of the frequency using the power characteristic of the frequency in the non-linear chirp pulse, and calculates the time response of the frequency in the non-linear chirp pulse from the rate of change of the frequency.
  • the generation device 1 will be illustrated.
  • FIG. 10 is a configuration diagram showing a radar system including the signal generation device 1 according to the second embodiment.
  • the same reference numerals as those in FIG. 1 indicate the same or corresponding parts, and thus the description thereof will be omitted.
  • FIG. 11 is a hardware configuration diagram showing the hardware of the signal generation device 1 according to the second embodiment. In FIG. 11, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts, and thus the description thereof will be omitted.
  • the storage unit 2 includes a power characteristic holding unit 24, a radar signal holding unit 22, and a display data holding unit 23.
  • the power characteristic holding unit 24 holds a function R (f) indicating the power corresponding to each frequency in the nonlinear chirped pulse as the power characteristic of the frequency in the nonlinear chirped pulse.
  • the time response calculation unit 14 is realized by, for example, the time response calculation circuit 34 shown in FIG.
  • the time response calculation unit 14 acquires each of the pulse time width T and the sampling interval Dt in the nonlinear chirped pulse output from the initial value setting unit 11.
  • the time response calculation unit 14 acquires the function R (f) stored by the power characteristic holding unit 24.
  • the time response calculation unit 14 uses the power characteristic of the frequency indicated by the function R (f), and uses the frequency change rate ⁇ F n / ⁇ T n (n is a natural number satisfying 1 ⁇ n ⁇ N: N is 3 or more. Calculate the natural number).
  • the time response calculation unit 14 calculates the time response f (t) of the frequency in the nonlinear chirped pulse from the rate of change ⁇ F n / ⁇ T n of the frequency.
  • the time response calculation unit 14 outputs the time response f (t) of the frequency to the signal generation unit 13.
  • each of the initial value setting unit 11, the time response calculation unit 14, and the signal generation unit 13, which are the components of the signal generation device 1, is realized by dedicated hardware as shown in FIG. doing. That is, it is assumed that the signal generation device 1 is realized by the initial value setting circuit 31, the time response calculation circuit 34, and the signal generation circuit 33.
  • Each of the initial value setting circuit 31, the time response calculation circuit 34, and the signal generation circuit 33 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. The thing is applicable.
  • the components of the signal generator 1 are not limited to those realized by dedicated hardware, but the signal generator 1 is realized by software, firmware, or a combination of software and firmware. It is also good.
  • FIG. 3 shows a program for causing a computer to execute each processing procedure in the initial value setting unit 11, the time response calculation unit 14, and the signal generation unit 13. It is stored in the memory 41. Then, the processor 42 shown in FIG. 3 executes the program stored in the memory 41.
  • FIG. 11 shows an example in which each of the components of the signal generation device 1 is realized by dedicated hardware
  • FIG. 3 shows an example in which the signal generation device 1 is realized by software, firmware, or the like. ..
  • this is only an example, and some components in the signal generation device 1 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, or the like.
  • the initial value setting unit 11 sets the sampling interval Dt of the nonlinear chirped pulse from the frequency bandwidth B of the nonlinear chirped pulse and the oversampling rate ⁇ .
  • the initial value setting unit 11 outputs each of the pulse time width T and the sampling interval Dt in the nonlinear chirped pulse to the time response calculation unit 14.
  • the time response calculation unit 14 acquires each of the pulse time width T and the sampling interval Dt in the nonlinear chirped pulse output from the initial value setting unit 11.
  • the time response calculation unit 14 acquires the function R (f) stored by the power characteristic holding unit 24.
  • FIG. 12 is an explanatory diagram showing an example of the function R (f).
  • the horizontal axis represents frequency and the vertical axis represents electric power.
  • the function R (f) shown in FIG. 12 shows each power in N frequency domains.
  • R (f 1 ) P 1 (F 0 ⁇ f 1 ⁇ F 1 )
  • R (f 2 ) P 2 (F 1 ⁇ f 2 ⁇ F 2 ) :
  • R (f N ) P N (F N-1 ⁇ f N ⁇ F N )
  • the time response calculation unit 14 calculates the amount of change ⁇ F n between the frequency F n and the frequency F n-1 .
  • n 1, 2, ..., N.
  • ⁇ F N F N ⁇ F N-1
  • the function R (f) represents the electric power corresponding to each frequency in a rectangular shape.
  • the time response calculation unit 14 calculates the frequency change rate ⁇ F n / ⁇ T n , assuming that the time required for the frequency transition is ⁇ T n (see FIG. 13) in the N frequency domains.
  • the following c is an arbitrary constant.
  • ⁇ F N / ⁇ T N c / P N
  • FIG. 13 is an explanatory diagram showing the time ⁇ T n required for the frequency transition and the frequency change amount ⁇ F n.
  • the horizontal axis represents time and the vertical axis represents frequency.
  • each of the time required for the transition frequency is ⁇ T 1 ⁇ ⁇ T N
  • the total time of ⁇ T 1 ⁇ ⁇ T N is the pulse time width T of the nonlinear chirp pulse.
  • the time response calculation unit 14 calculates the time response f (t) of the frequency in the nonlinear chirped pulse from the char plate ⁇ n having the frequency change rate ⁇ F n / ⁇ T n. ..
  • the time response calculation unit 14 outputs each of the frequency time response f (t) and the sampling interval Dt to the signal generation unit 13.
  • the signal generation unit 13 acquires each of the time response f (t) of the frequency output from the time response calculation unit 14 and the sampling interval Dt. As shown in the following equation (20), the signal generation unit 13 calculates the phase change amount D p (g) using each of the frequency time response f (t) and the sampling interval Dt.
  • the signal generation unit 13 adds the phase change amount D p (g) to the initial value p (0) of the phase time response shown in the following equation (21) to obtain the phase time response p (g). Is calculated.
  • the signal generation unit 13 generates a non-linear chirped pulse having a phase time response p (g) as the radar signal s (m).
  • the signal generation unit 13 outputs the generated nonlinear chirped pulse as a radar signal s (m) to the radar signal holding unit 22 of the storage unit 2.
  • the time response calculation unit 14 calculates the rate of change of the frequency using the power characteristic of the frequency in the non-linear chirp pulse, and calculates the time response of the frequency in the non-linear chirp pulse from the rate of change of the frequency.
  • the signal generation device 1 shown in FIG. 10 was configured. Therefore, the signal generation device 1 shown in FIG. 10 can prevent deterioration of the signal waveform of the nonlinear chirped pulse due to the inclusion of an error in the time response of the phase, similarly to the signal generation device 1 shown in FIG. ..
  • the present disclosure is suitable for a signal generator, a signal generation method, and a signal generation program that generate a non-linear chirped pulse.

Abstract

A signal generation device (1) comprises: a time response calculation unit (12) for using power characteristics of a frequency in a non-linear chirp pulse with asymmetry power distribution of frequency to calculate a time response of the frequency in the non-linear chirp pulse; and a signal generation unit (13) for using the time response of the frequency calculated by the time response calculation unit (12) and a sampling period of the non-linear chirp pulse to calculate a time response of a phase in the non-linear chirp pulse and generate a non-linear chirp pulse having the time response of the phase.

Description

信号生成装置、信号生成方法及び信号生成プログラムSignal generator, signal generation method and signal generation program
　本開示は、非線形チャープパルスを生成する信号生成装置、信号生成方法及び信号生成プログラムに関するものである。 The present disclosure relates to a signal generator, a signal generation method, and a signal generation program that generate a non-linear chirped pulse.
　従来のレーダ装置の中には、レーダ信号として、チャープパルスを用いるレーダ装置がある。チャープパルスのサイドローブを低減できれば、レーダ装置における目標の検出性能等を高めることができる。サイドローブが低減されているチャープパルスとして、周波数の電力分布に偏りがある非線形チャープパルスがある。レーダ信号として、非線形チャープパルスを用いる場合、非線形チャープパルスは、実用上、等時間間隔でサンプリングされている必要がある。等時間間隔でサンプリングされている非線形チャープパルスを生成するには、非線形チャープパルスにおける位相の時間応答を決定する必要がある。 Among conventional radar devices, there is a radar device that uses a chirped pulse as a radar signal. If the side lobe of the chirped pulse can be reduced, the target detection performance in the radar device can be improved. As a chirped pulse with reduced side lobes, there is a non-linear chirped pulse in which the frequency power distribution is biased. When a non-linear chirped pulse is used as a radar signal, the non-linear chirped pulse needs to be sampled at equal time intervals in practical use. In order to generate a nonlinear chirped pulse sampled at equal time intervals, it is necessary to determine the time response of the phase in the nonlinear chirped pulse.
　以下の非特許文献１には、非線形チャープパルスにおける位相の時間応答を、テイラー重みを有する多項式によって近似する方法が開示されている。 The following Non-Patent Document 1 discloses a method of approximating the time response of a phase in a nonlinear chirped pulse by a polynomial having a Taylor weight.
　非特許文献１に開示されている方法では、非線形チャープパルスにおける位相の時間応答を多項式で近似しているため、位相の時間応答に誤差が含まれる。位相の時間応答に誤差が含まれることによって、非線形チャープパルスの信号波形が劣化してしまうという課題があった。 In the method disclosed in Non-Patent Document 1, since the time response of the phase in the nonlinear charp pulse is approximated by a polynomial, an error is included in the time response of the phase. There is a problem that the signal waveform of the nonlinear chirped pulse is deteriorated due to the inclusion of an error in the time response of the phase.
　本開示は、上記のような課題を解決するためになされたもので、位相の時間応答に誤差が含まれることに伴う、非線形チャープパルスの信号波形の劣化を防ぐことができる信号生成装置、信号生成方法及び信号生成プログラムを得ることを目的とする。 The present disclosure has been made to solve the above-mentioned problems, and is a signal generator and a signal capable of preventing deterioration of the signal waveform of a non-linear chap pulse due to an error in the time response of the phase. The purpose is to obtain a generation method and a signal generation program.
　本開示に係る信号生成装置は、周波数の電力分布に偏りがある非線形チャープパルスにおける周波数の電力特性を用いて、非線形チャープパルスにおける周波数の時間応答を算出する時間応答算出部と、時間応答算出部により算出された周波数の時間応答と、非線形チャープパルスのサンプリング間隔とを用いて、非線形チャープパルスにおける位相の時間応答を算出し、位相の時間応答を有する非線形チャープパルスを生成する信号生成部とを備えるものである。 The signal generator according to the present disclosure includes a time response calculation unit and a time response calculation unit that calculate the time response of the frequency in the non-linear chirp pulse by using the power characteristic of the frequency in the non-linear chirp pulse having a bias in the power distribution of the frequency. Using the time response of the frequency calculated by To prepare.
　本開示によれば、位相の時間応答に誤差が含まれることに伴う、非線形チャープパルスの信号波形の劣化を防ぐことができる。 According to the present disclosure, it is possible to prevent deterioration of the signal waveform of the nonlinear chirped pulse due to the inclusion of an error in the time response of the phase.
実施の形態１に係る信号生成装置１を含むレーダシステムを示す構成図である。It is a block diagram which shows the radar system which includes the signal generation apparatus 1 which concerns on Embodiment 1. FIG. 実施の形態１に係る信号生成装置１のハードウェアを示すハードウェア構成図である。It is a hardware block diagram which shows the hardware of the signal generation apparatus 1 which concerns on Embodiment 1. FIG. 信号生成装置１が、ソフトウェア又はファームウェア等によって実現される場合のコンピュータのハードウェア構成図である。FIG. 5 is a hardware configuration diagram of a computer when the signal generator 1 is realized by software, firmware, or the like. 実施の形態１に係る信号生成装置１の処理手順である信号生成方法を示すフローチャートである。It is a flowchart which shows the signal generation method which is the processing procedure of the signal generation apparatus 1 which concerns on Embodiment 1. FIG. 信号生成部１３により生成されたレーダ信号ｓ（ｍ）の時間周波数特性を示す説明図である。It is explanatory drawing which shows the time frequency characteristic of the radar signal s (m) generated by the signal generation unit 13. 信号生成部１３により生成されたレーダ信号ｓ（ｍ）における周波数上の電力特性を示す説明図である。It is explanatory drawing which shows the electric power characteristic on the frequency in the radar signal s (m) generated by the signal generation unit 13. パルス圧縮後のレーダ信号ｓ（ｍ）’を示す説明図である。It is explanatory drawing which shows the radar signal s (m)' after pulse compression. 図８Ａ及び図８Ｂのそれぞれは、形状が単峰型である窓関数Ｗ（ｆ（ｍ））の一例を示す説明図である。Each of FIGS. 8A and 8B is an explanatory diagram showing an example of a window function W (f (m)) having a single peak shape. 図９Ａ及び図９Ｂのそれぞれは、形状が複峰型である窓関数Ｗ（ｆ（ｍ））の一例を示す説明図である。Each of FIGS. 9A and 9B is an explanatory diagram showing an example of a window function W (f (m)) having a compound peak shape. 実施の形態２に係る信号生成装置１を含むレーダシステムを示す構成図である。It is a block diagram which shows the radar system which includes the signal generation apparatus 1 which concerns on Embodiment 2. FIG. 実施の形態２に係る信号生成装置１のハードウェアを示すハードウェア構成図である。It is a hardware block diagram which shows the hardware of the signal generation apparatus 1 which concerns on Embodiment 2. FIG. 関数Ｒ（ｆ）の一例を示す説明図である。It is explanatory drawing which shows an example of the function R (f). 周波数の遷移に要する時間ΔＴｎと、周波数の変化量ΔＦｎとを示す説明図である。It is explanatory drawing which shows the time ΔT n required for the frequency transition, and the frequency change amount ΔF n.
　以下、本開示をより詳細に説明するために、本開示を実施するための形態について、添付の図面に従って説明する。 Hereinafter, in order to explain the present disclosure in more detail, a mode for carrying out the present disclosure will be described with reference to the attached drawings.
実施の形態１．
　図１は、実施の形態１に係る信号生成装置１を含むレーダシステムを示す構成図である。
　図２は、実施の形態１に係る信号生成装置１のハードウェアを示すハードウェア構成図である。
　レーダシステムは、信号生成装置１、記憶部２、レーダ信号処理部３、レーダ部４及び表示部５を備えている。
　信号生成装置１は、非線形チャープパルスを生成し、非線形チャープパルスをレーダ信号として、記憶部２に出力する。 Embodiment 1.
FIG. 1 is a configuration diagram showing a radar system including the signal generation device 1 according to the first embodiment.
FIG. 2 is a hardware configuration diagram showing the hardware of the signal generation device 1 according to the first embodiment.
The radar system includes a signal generation device 1, a storage unit 2, a radar signal processing unit 3, a radar unit 4, and a display unit 5.
The signal generation device 1 generates a non-linear chirped pulse and outputs the non-linear chirped pulse as a radar signal to the storage unit 2.
　記憶部２は、例えば、記憶処理回路によって実現される。
　記憶部２は、窓関数、信号生成装置１により生成されたレーダ信号及びレーダ信号処理部３により生成された表示データのそれぞれを記憶している。
　記憶処理回路は、例えば、ＲＡＭ（Ｒａｎｄｏｍ　Ａｃｃｅｓｓ　Ｍｅｍｏｒｙ）、ＲＯＭ（Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒｙ）、フラッシュメモリ、ＥＰＲＯＭ（Ｅｒａｓａｂｌｅ　Ｐｒｏｇｒａｍｍａｂｌｅ　Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒｙ）、ＥＥＰＲＯＭ（Ｅｌｅｃｔｒｉｃａｌｌｙ　Ｅｒａｓａｂｌｅ　Ｐｒｏｇｒａｍｍａｂｌｅ　Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒy）等の不揮発性又は揮発性の半導体メモリ、磁気ディスク、フレキシブルディスク、光ディスク、コンパクトディスク、ミニディスク、あるいは、ＤＶＤ（Ｄｉｇｉｔａｌ　Ｖｅｒｓａｔｉｌｅ　Ｄｉｓｃ）が該当する。 The storage unit 2 is realized by, for example, a storage processing circuit.
The storage unit 2 stores each of the window function, the radar signal generated by the signal generation device 1, and the display data generated by the radar signal processing unit 3.
The storage processing circuit includes, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Flexible Memory), an EEPROM (Electrically Flexible Memory), or the like. A semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versaille Disc) is applicable.
　レーダ信号処理部３は、記憶部２により記憶されているレーダ信号をレーダ部４に出力し、レーダ部４から出力された受信信号を取得する。
　レーダ信号処理部３は、レーダ信号及び受信信号のそれぞれを用いて、目標の検出処理、あるいは、合成開口レーダ画像の生成処理等を実施する。
　レーダ信号処理部３は、目標の検出処理結果を表示するための表示データ、あるいは、合成開口レーダ画像を表示するための表示データを生成し、生成した表示データを記憶部２に出力する。 The radar signal processing unit 3 outputs the radar signal stored in the storage unit 2 to the radar unit 4, and acquires the received signal output from the radar unit 4.
The radar signal processing unit 3 uses each of the radar signal and the received signal to perform target detection processing, synthetic aperture radar image generation processing, and the like.
The radar signal processing unit 3 generates display data for displaying the target detection processing result or display data for displaying the synthetic aperture radar image, and outputs the generated display data to the storage unit 2.
　レーダ部４は、レーダ信号処理部３から出力されたレーダ信号に係る電波を空間に放射し、目標に反射された電波を受信する。
　レーダ部４は、電波の受信信号をレーダ信号処理部３に出力する。
　表示部５は、例えば、液晶ディスプレイを備えている。
　表示部５は、記憶部２により記憶されている表示データに従って、目標の検出処理結果、あるいは、合成開口レーダ画像を液晶ディスプレイに表示させる。 The radar unit 4 radiates radio waves related to the radar signal output from the radar signal processing unit 3 into space, and receives the radio waves reflected by the target.
The radar unit 4 outputs a radio wave reception signal to the radar signal processing unit 3.
The display unit 5 includes, for example, a liquid crystal display.
The display unit 5 displays the target detection processing result or the synthetic aperture radar image on the liquid crystal display according to the display data stored in the storage unit 2.
　信号生成装置１は、初期値設定部１１、時間応答算出部１２及び信号生成部１３を備えている。
　初期値設定部１１は、例えば、図２に示す初期値設定回路３１によって実現される。
　初期値設定部１１の内部メモリは、設計諸元として、非線形チャープパルスの周波数帯域幅Ｂ、非線形チャープパルスのパルス時間幅Ｔ及びオーバーサンプリング率αのそれぞれを記憶している。
　初期値設定部１１は、周波数帯域幅Ｂとオーバーサンプリング率αとから、非線形チャープパルスのサンプリング間隔Ｄｔを設定する。
　初期値設定部１１は、周波数帯域幅Ｂとパルス時間幅Ｔとから、暫定のチャープ率γ０を設定する。
　初期値設定部１１は、サンプリング間隔Ｄｔ及び暫定のチャープ率γ０のそれぞれを時間応答算出部１２に出力する。
　図１に示す信号生成装置１では、初期値設定部１１の内部メモリが、周波数帯域幅Ｂ、パルス時間幅Ｔ及びオーバーサンプリング率αのそれぞれを記憶している。しかし、これは一例に過ぎず、周波数帯域幅Ｂ、パルス時間幅Ｔ及びオーバーサンプリング率αのそれぞれは、信号生成装置１の外部から与えられるものであってもよい。 The signal generation device 1 includes an initial value setting unit 11, a time response calculation unit 12, and a signal generation unit 13.
The initial value setting unit 11 is realized by, for example, the initial value setting circuit 31 shown in FIG.
The internal memory of the initial value setting unit 11 stores each of the frequency bandwidth B of the non-linear charp pulse, the pulse time width T of the non-linear charp pulse, and the oversampling rate α as design specifications.
The initial value setting unit 11 sets the sampling interval Dt of the nonlinear chirped pulse from the frequency bandwidth B and the oversampling rate α.
The initial value setting unit 11 sets a provisional chirp rate γ 0 from the frequency bandwidth B and the pulse time width T.
The initial value setting unit 11 outputs each of the sampling interval Dt and the provisional chirp rate γ 0 to the time response calculation unit 12.
In the signal generation device 1 shown in FIG. 1, the internal memory of the initial value setting unit 11 stores each of the frequency bandwidth B, the pulse time width T, and the oversampling rate α. However, this is only an example, and each of the frequency bandwidth B, the pulse time width T, and the oversampling rate α may be given from the outside of the signal generation device 1.
　時間応答算出部１２は、例えば、図２に示す時間応答算出回路３２によって実現される。
　時間応答算出部１２は、非線形チャープパルスにおける周波数の電力特性を用いて、非線形チャープパルスにおける周波数の時間応答として、サンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）を算出する。ｍは、Ｍ０≦ｍ≦Ｍ１の範囲内の整数である。Ｍ０及びＭ１のそれぞれは整数である。
　即ち、時間応答算出部１２は、初期値設定部１１から出力されたサンプリング間隔Ｄｔ及び暫定のチャープ率γ０のそれぞれを取得し、記憶部２の窓関数保持部２１により記憶されている窓関数Ｗ（ｆ（ｍ））を取得する。窓関数Ｗ（ｆ（ｍ））は、周波数の電力分布に偏りがある非線形チャープパルスにおける周波数ｆ（ｍ）の電力特性を示すものである。
　そして、時間応答算出部１２は、暫定のチャープ率γ０及び窓関数Ｗ（ｆ（ｍ））のそれぞれを用いて、サンプリング間隔Ｄｔの間に変化している周波数の変化量Ｄｆ（ｍ）を算出する。
　そして、時間応答算出部１２は、周波数の変化量Ｄｆ（ｍ）から非線形チャープパルスにおける周波数の時間応答として、サンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）を算出する。
　時間応答算出部１２は、サンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）及びサンプリング間隔Ｄｔのそれぞれを信号生成部１３に出力する。 The time response calculation unit 12 is realized by, for example, the time response calculation circuit 32 shown in FIG.
The time response calculation unit 12 calculates the frequency f (m) at the sampling time m × Dt as the time response of the frequency in the nonlinear charp pulse by using the power characteristic of the frequency in the nonlinear charp pulse. m is an integer within the range of M 0 ≤ m ≤ M 1. Each of M 0 and M 1 is an integer.
That is, the time response calculation unit 12 acquires each of the sampling interval Dt output from the initial value setting unit 11 and the provisional charp rate γ 0 , and is stored by the window function holding unit 21 of the storage unit 2. W (f (m)) is acquired. The window function W (f (m)) shows the power characteristic of the frequency f (m) in the nonlinear chirped pulse in which the power distribution of the frequency is biased.
Then, the time response calculation unit 12 uses each of the provisional chirp rate γ 0 and the window function W (f (m)) to determine the amount of change Df (m) of the frequency changing during the sampling interval Dt. calculate.
Then, the time response calculation unit 12 calculates the frequency f (m) at the sampling time m × Dt as the time response of the frequency in the non-linear chap pulse from the frequency change amount Df (m).
The time response calculation unit 12 outputs each of the frequency f (m) and the sampling interval Dt at the sampling time m × Dt to the signal generation unit 13.
　信号生成部１３は、例えば、図２に示す信号生成回路３３によって実現される。
　信号生成部１３は、時間応答算出部１２により算出された周波数の時間応答と、非線形チャープパルスのサンプリング間隔Ｄｔとを用いて、非線形チャープパルスにおける位相の時間応答ｐ（ｍ）を算出する。位相の時間応答ｐ（ｍ）は、それぞれのサンプリング時刻ｍ×Ｄｔについて算出される。
　信号生成部１３は、レーダ信号ｓ（ｍ）として、位相の時間応答ｐ（ｍ）を有する非線形チャープパルスを生成する。
　信号生成部１３は、生成した非線形チャープパルスをレーダ信号ｓ（ｍ）として、記憶部２のレーダ信号保持部２２に出力する。 The signal generation unit 13 is realized by, for example, the signal generation circuit 33 shown in FIG.
The signal generation unit 13 calculates the time response p (m) of the phase in the nonlinear charp pulse by using the time response of the frequency calculated by the time response calculation unit 12 and the sampling interval Dt of the nonlinear charp pulse. The phase time response p (m) is calculated for each sampling time m × Dt.
The signal generation unit 13 generates a non-linear chirped pulse having a phase time response p (m) as a radar signal s (m).
The signal generation unit 13 outputs the generated nonlinear chirped pulse as a radar signal s (m) to the radar signal holding unit 22 of the storage unit 2.
　記憶部２は、窓関数保持部２１、レーダ信号保持部２２及び表示データ保持部２３を備えている。
　窓関数保持部２１は、窓関数Ｗ（ｆ）を記憶している。
　レーダ信号保持部２２は、信号生成部１３により生成されたレーダ信号ｓ（ｍ）を記憶する。
　表示データ保持部２３は、レーダ信号処理部３により生成された表示データを記憶する。 The storage unit 2 includes a window function holding unit 21, a radar signal holding unit 22, and a display data holding unit 23.
The window function holding unit 21 stores the window function W (f).
The radar signal holding unit 22 stores the radar signal s (m) generated by the signal generating unit 13.
The display data holding unit 23 stores the display data generated by the radar signal processing unit 3.
　図１では、信号生成装置１の構成要素である初期値設定部１１、時間応答算出部１２及び信号生成部１３のそれぞれが、図２に示すような専用のハードウェアによって実現されるものを想定している。即ち、信号生成装置１が、初期値設定回路３１、時間応答算出回路３２及び信号生成回路３３によって実現されるものを想定している。
　初期値設定回路３１、時間応答算出回路３２及び信号生成回路３３のそれぞれは、例えば、単一回路、複合回路、プログラム化したプロセッサ、並列プログラム化したプロセッサ、ＡＳＩＣ（Ａｐｐｌｉｃａｔｉｏｎ　Ｓｐｅｃｉｆｉｃ　Ｉｎｔｅｇｒａｔｅｄ　Ｃｉｒｃｕｉｔ）、ＦＰＧＡ（Ｆｉｅｌｄ－Ｐｒｏｇｒａｍｍａｂｌｅ　Ｇａｔｅ　Ａｒｒａｙ）、又は、これらを組み合わせたものが該当する。 In FIG. 1, it is assumed that each of the initial value setting unit 11, the time response calculation unit 12, and the signal generation unit 13, which are the components of the signal generation device 1, is realized by dedicated hardware as shown in FIG. doing. That is, it is assumed that the signal generation device 1 is realized by the initial value setting circuit 31, the time response calculation circuit 32, and the signal generation circuit 33.
Each of the initial value setting circuit 31, the time response calculation circuit 32, and the signal generation circuit 33 includes, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), and an FPGA (FPGA). Field-Programmable Gate Array) or a combination of these is applicable.
　信号生成装置１の構成要素は、専用のハードウェアによって実現されるものに限るものではなく、信号生成装置１が、ソフトウェア、ファームウェア、又は、ソフトウェアとファームウェアとの組み合わせによって実現されるものであってもよい。
　ソフトウェア又はファームウェアは、プログラムとして、コンピュータのメモリに格納される。コンピュータは、プログラムを実行するハードウェアを意味し、例えば、ＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）、中央処理装置、処理装置、演算装置、マイクロプロセッサ、マイクロコンピュータ、プロセッサ、あるいは、ＤＳＰ（Ｄｉｇｉｔａｌ　Ｓｉｇｎａｌ　Ｐｒｏｃｅｓｓｏｒ）が該当する。 The components of the signal generator 1 are not limited to those realized by dedicated hardware, but the signal generator 1 is realized by software, firmware, or a combination of software and firmware. It is also good.
The software or firmware is stored as a program in the memory of the computer. A computer means hardware that executes 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.
　図３は、信号生成装置１が、ソフトウェア又はファームウェア等によって実現される場合のコンピュータのハードウェア構成図である。
　信号生成装置１が、ソフトウェア又はファームウェア等によって実現される場合、初期値設定部１１、時間応答算出部１２及び信号生成部１３におけるそれぞれの処理手順をコンピュータに実行させるためのプログラムがメモリ４１に格納される。そして、コンピュータのプロセッサ４２がメモリ４１に格納されているプログラムを実行する。 FIG. 3 is a hardware configuration diagram of a computer when the signal generation device 1 is realized by software, firmware, or the like.
When the signal generation device 1 is realized by software, firmware, or the like, a program for causing a computer to execute each processing procedure in the initial value setting unit 11, the time response calculation unit 12, and the signal generation unit 13 is stored in the memory 41. Will be done. Then, the processor 42 of the computer executes the program stored in the memory 41.
　また、図２では、信号生成装置１の構成要素のそれぞれが専用のハードウェアによって実現される例を示し、図３では、信号生成装置１がソフトウェア又はファームウェア等によって実現される例を示している。しかし、これは一例に過ぎず、信号生成装置１における一部の構成要素が専用のハードウェアによって実現され、残りの構成要素がソフトウェア又はファームウェア等によって実現されるものであってもよい。 Further, FIG. 2 shows an example in which each of the components of the signal generation device 1 is realized by dedicated hardware, and FIG. 3 shows an example in which the signal generation device 1 is realized by software, firmware, or the like. .. However, this is only an example, and some components in the signal generation device 1 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, or the like.
　次に、図１に示す信号生成装置１の動作について説明する。
　図４は、実施の形態１に係る信号生成装置１の処理手順である信号生成方法を示すフローチャートである。 Next, the operation of the signal generation device 1 shown in FIG. 1 will be described.
FIG. 4 is a flowchart showing a signal generation method which is a processing procedure of the signal generation device 1 according to the first embodiment.
　初期値設定部１１は、以下の式（１）に示すように、非線形チャープパルスの周波数帯域幅Ｂと、オーバーサンプリング率αとから、非線形チャープパルスのサンプリング間隔Ｄｔを設定する（図４のステップＳＴ１）。

Figure JPOXMLDOC01-appb-I000001
　初期値設定部１１は、以下の式（２）に示すように、非線形チャープパルスの周波数帯域幅Ｂと、非線形チャープパルスのパルス時間幅Ｔとから、暫定のチャープ率γ０を設定する（図４のステップＳＴ１）。

Figure JPOXMLDOC01-appb-I000002
　初期値設定部１１は、サンプリング間隔Ｄｔ及び暫定のチャープ率γ０のそれぞれを時間応答算出部１２に出力する。 As shown in the following equation (1), the initial value setting unit 11 sets the sampling interval Dt of the nonlinear chirped pulse from the frequency bandwidth B of the nonlinear chirped pulse and the oversampling rate α (step of FIG. 4). ST1).

Figure JPOXMLDOC01-appb-I000001
As shown in the following equation (2), the initial value setting unit 11 sets a provisional chirp rate γ 0 from the frequency bandwidth B of the nonlinear chirp pulse and the pulse time width T of the nonlinear chirp pulse (FIG. Step 4 ST1).

Figure JPOXMLDOC01-appb-I000002
The initial value setting unit 11 outputs each of the sampling interval Dt and the provisional chirp rate γ 0 to the time response calculation unit 12.
　時間応答算出部１２は、初期値設定部１１から出力されたサンプリング間隔Ｄｔ及び暫定のチャープ率γ０のそれぞれを取得し、窓関数保持部２１により記憶されている窓関数Ｗ（ｆ（ｍ））を取得する。
　窓関数Ｗ（ｆ（ｍ））は、周波数の電力分布に偏りがある非線形チャープパルスにおける周波数ｆ（ｍ）の電力特性を示すものである。
　図１に示す信号生成装置１は、周波数ｆ（ｍ）の中心周波数が０［Ｈｚ］の等価低域系であることを前提とする。周波数ｆ（ｍ）の帯域は、－Ｂ／２≦ｆ（ｍ）≦Ｂ／２である。 The time response calculation unit 12 acquires each of the sampling interval Dt output from the initial value setting unit 11 and the provisional charp rate γ 0 , and the window function W (f (m)) stored by the window function holding unit 21. ) To get.
The window function W (f (m)) shows the power characteristic of the frequency f (m) in the nonlinear chirped pulse in which the power distribution of the frequency is biased.
The signal generator 1 shown in FIG. 1 is premised on an equivalent low frequency system in which the center frequency of the frequency f (m) is 0 [Hz]. The band of the frequency f (m) is −B / 2 ≦ f (m) ≦ B / 2.
　時間応答算出部１２は、以下の式（３）に示すように、暫定のチャープ率γ０及び窓関数Ｗ（ｆ（ｍ））のそれぞれを用いて、サンプリング間隔Ｄｔの間に変化している周波数の変化量Ｄｆ（ｍ）を算出する（図４のステップＳＴ２）。

Figure JPOXMLDOC01-appb-I000003
　式（３）において、Ｗａｖｅは、－Ｂ／２≦ｆ（ｍ）≦Ｂ／２の帯域における窓関数Ｗ（ｆ（ｍ））の平均値である。 As shown in the following equation (3), the time response calculation unit 12 changes during the sampling interval Dt using each of the provisional chirp rate γ 0 and the window function W (f (m)). The amount of change in frequency Df (m) is calculated (step ST2 in FIG. 4).

Figure JPOXMLDOC01-appb-I000003
In the formula (3), Wave is the average value of the window function W (f (m)) in the band of −B / 2 ≦ f (m) ≦ B / 2.
　時間応答算出部１２は、周波数の変化量Ｄｆ（ｍ）から非線形チャープパルスにおける周波数の時間応答として、サンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）を算出する（図４のステップＳＴ３）。
　時間応答算出部１２は、サンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）及びサンプリング間隔Ｄｔのそれぞれを信号生成部１３に出力する。
　以下、時間応答算出部１２による周波数ｆ（ｍ）の算出処理を具体的に説明する。 The time response calculation unit 12 calculates the frequency f (m) at the sampling time m × Dt as the time response of the frequency in the nonlinear chap pulse from the frequency change amount Df (m) (step ST3 in FIG. 4).
The time response calculation unit 12 outputs each of the frequency f (m) and the sampling interval Dt at the sampling time m × Dt to the signal generation unit 13.
Hereinafter, the calculation process of the frequency f (m) by the time response calculation unit 12 will be specifically described.
　まず、時間応答算出部１２は、周波数ｆ（０）を算出する。図１に示す信号生成装置１では、周波数ｆ（ｍ）の中心周波数が０［Ｈｚ］の等価低域系であることを前提としているため、周波数ｆ（０）は、以下の式（４）に示すように、０である。

Figure JPOXMLDOC01-appb-I000004
First, the time response calculation unit 12 calculates the frequency f (0). Since the signal generator 1 shown in FIG. 1 is premised on the fact that the center frequency of the frequency f (m) is an equivalent low frequency system of 0 [Hz], the frequency f (0) is expressed by the following equation (4). As shown in, it is 0.

Figure JPOXMLDOC01-appb-I000004
　次に、時間応答算出部１２は、正の周波数領域の周波数ｆ（ｍ）として、０よりも大きく、かつ、Ｂ／２以下の周波数の全てを算出する。即ち、時間応答算出部１２は、以下の式（５）に示すように、サンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）を繰り返し算出する。

Figure JPOXMLDOC01-appb-I000005
　図１に示す信号生成装置１では、ｍ＝Ｍ１のとき、ｆ（ｍ＋１）がＢ／２を上回り、ｍ＝Ｍ１－１のとき、ｆ（ｍ＋１）がＢ／２を上回らないものとする。 Next, the time response calculation unit 12 calculates all frequencies greater than 0 and B / 2 or less as frequencies f (m) in the positive frequency domain. That is, the time response calculation unit 12 repeatedly calculates the frequency f (m) at the sampling time m × Dt, as shown in the following equation (5).

Figure JPOXMLDOC01-appb-I000005
In the signal generation device 1 shown in FIG. 1, when m = M 1, f (m + 1) exceeds the B / 2, when m = M 1 -1, and that f (m + 1) does not exceed B / 2 do.
　時間応答算出部１２は、負の周波数領域の周波数ｆ（ｍ）として、０よりも小さく、かつ、－Ｂ／２以上の周波数の全てを算出する。即ち、時間応答算出部１２は、以下の式（７）に示すように、サンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）を繰り返し算出する。

Figure JPOXMLDOC01-appb-I000006
　図１に示す信号生成装置１では、ｍ＝Ｍ０のとき、ｆ（ｍ－１）が－Ｂ／２を下回り、ｍ＝Ｍ０＋１のとき、ｆ（ｍ－１）が－Ｂ／２を下回らないものとする。 The time response calculation unit 12 calculates all frequencies smaller than 0 and greater than or equal to −B / 2 as the frequency f (m) in the negative frequency region. That is, the time response calculation unit 12 repeatedly calculates the frequency f (m) at the sampling time m × Dt, as shown in the following equation (7).

Figure JPOXMLDOC01-appb-I000006
In the signal generator 1 shown in FIG. 1, when m = M 0 , f (m-1) is less than −B / 2, and when m = M 0 + 1, f (m-1) is −B / 2. It shall not be less than.
　時間応答算出部１２は、繰り返し算出したサンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）及びサンプリング間隔Ｄｔのそれぞれを信号生成部１３に出力する。
　時間応答算出部１２により繰り返し算出されたサンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）は、サンプリング間隔Ｄｔだけ異なる複数の時刻の周波数である。このため、時間応答算出部１２により繰り返し算出されたサンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）は、等時間間隔でサンプリングが行われたものでありながら、窓関数Ｗ（ｆ（ｍ））の逆数によって重みが付けられている変化量Ｄｆ（ｍ）と相関がある。 The time response calculation unit 12 outputs each of the frequency f (m) and the sampling interval Dt at the sampling time m × Dt calculated repeatedly to the signal generation unit 13.
The frequency f (m) at the sampling time m × Dt repeatedly calculated by the time response calculation unit 12 is a frequency of a plurality of times different by the sampling interval Dt. Therefore, the frequency f (m) at the sampling time m × Dt repeatedly calculated by the time response calculation unit 12 is the window function W (f (m)) even though the sampling is performed at equal time intervals. It correlates with the amount of change Df (m) weighted by the reciprocal.
　図１に示す信号生成装置１では、時間応答算出部１２が、正の周波数領域の周波数ｆ（ｍ）を式（５）によって算出し、負の周波数領域の周波数ｆ（ｍ）を式（７）によって算出している。しかし、これは一例に過ぎず、例えば、Ｗ（ｆ（ｍ））＝Ｗ（－ｆ（ｍ））のように、電力分布に対称性がある場合、正の周波数領域の周波数ｆ（ｍ）を式（５）によって算出したのち、負の周波数領域の周波数ｆ（ｍ）を、以下の式（９）に示すように与えてもよい。

Figure JPOXMLDOC01-appb-I000007
　式（９）の右辺におけるｆ（－ｍ）は、正の周波数領域の周波数ｆ（ｍ）におけるｍを－ｍに置き換えたものである。 In the signal generator 1 shown in FIG. 1, the time response calculation unit 12 calculates the frequency f (m) in the positive frequency domain by the equation (5), and the frequency f (m) in the negative frequency domain is calculated by the equation (7). ) Is calculated. However, this is only an example, and when the power distribution is symmetric, for example, W (f (m)) = W (−f (m)), the frequency f (m) in the positive frequency domain. Is calculated by the equation (5), and then the frequency f (m) in the negative frequency region may be given as shown in the following equation (9).

Figure JPOXMLDOC01-appb-I000007
The f (−m) on the right side of the equation (9) is obtained by replacing m at the frequency f (m) in the positive frequency domain with −m.
　信号生成部１３は、時間応答算出部１２から出力されたサンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）及びサンプリング間隔Ｄｔのそれぞれを取得する。
　信号生成部１３は、サンプリング時刻ｍ×Ｄｔにおける周波数ｆ（ｍ）とサンプリング間隔Ｄｔとを用いて、非線形チャープパルスにおける位相の時間応答ｐ（ｍ）を算出する（図４のステップＳＴ４）。位相の時間応答ｐ（ｍ）は、サンプリング間隔Ｄｔだけ異なる複数の時刻の位相である。
　以下、信号生成部１３による位相の時間応答ｐ（ｍ）の算出処理を具体的に説明する。 The signal generation unit 13 acquires the frequency f (m) and the sampling interval Dt at the sampling time m × Dt output from the time response calculation unit 12.
The signal generation unit 13 calculates the time response p (m) of the phase in the non-linear chap pulse by using the frequency f (m) at the sampling time m × Dt and the sampling interval Dt (step ST4 in FIG. 4). The phase time response p (m) is a plurality of time phases that differ by the sampling interval Dt.
Hereinafter, the process of calculating the phase time response p (m) by the signal generation unit 13 will be specifically described.
　まず、信号生成部１３は、周波数ｆ（ｍ）によって与えられる位相の変化量をＤｐ（ｍ）として、以下の式（１０）及び式（１１）に示すように、ｍ＝Ｍ０のときの、位相の変化量Ｄｐ（Ｍ０）及び位相の時間応答ｐ（Ｍ０）のそれぞれを算出する。

Figure JPOXMLDOC01-appb-I000008
First, the signal generation unit 13 sets the amount of phase change given by the frequency f (m) as D p (m), and when m = M 0 as shown in the following equations (10) and (11). Each of the phase change amount D p (M 0 ) and the phase time response p (M 0 ) is calculated.

Figure JPOXMLDOC01-appb-I000008
　次に、信号生成部１３は、Ｍ０＋１≦ｍ≦Ｍ１の範囲で、ｍが１ずつ変化するものとして、以下の式（１２）及び式（１３）に示すように、位相の変化量Ｄｐ（ｍ）及び位相の時間応答ｐ（ｍ）のそれぞれを算出する。

Figure JPOXMLDOC01-appb-I000009
Next, the signal generation unit 13 assumes that m changes by 1 in the range of M 0 + 1 ≦ m ≦ M 1, and as shown in the following equations (12) and (13), the amount of phase change. Each of D p (m) and the phase time response p (m) is calculated.

Figure JPOXMLDOC01-appb-I000009
　次に、信号生成部１３は、Ｍ０≦ｍ≦Ｍ１の範囲で、ｍが１ずつ変化するものとして、以下の式（１４）に示すように、レーダ信号ｓ（ｍ）として、位相の時間応答ｐ（ｍ）を有する非線形チャープパルスを生成する（図４のステップＳＴ５）。

Figure JPOXMLDOC01-appb-I000010
　信号生成部１３は、生成した非線形チャープパルスをレーダ信号ｓ（ｍ）として、記憶部２のレーダ信号保持部２２に出力する。 Next, the signal generation unit 13 assumes that m changes by 1 in the range of M 0 ≤ m ≤ M 1, and as shown in the following equation (14), the phase of the radar signal s (m) is changed. A non-linear chirped pulse having a time response p (m) is generated (step ST5 in FIG. 4).

Figure JPOXMLDOC01-appb-I000010
The signal generation unit 13 outputs the generated nonlinear chirped pulse as a radar signal s (m) to the radar signal holding unit 22 of the storage unit 2.
　図５は、信号生成部１３により生成されたレーダ信号ｓ（ｍ）の時間周波数特性を示す説明図である。
　図５において、横軸は時間を示し、縦軸は周波数を示している。
　太線は、窓関数Ｗ（ｆ（ｍ））として、Ｈａｍｍｉｎｇ窓を用いた場合のレーダ信号ｓ（ｍ）の時間周波数特性を示している。細線は、線形チャープの時間周波数特性を示している。
　図６は、信号生成部１３により生成されたレーダ信号ｓ（ｍ）における周波数上の電力特性を示す説明図である。
　図６において、横軸は周波数を示し、縦軸はパルス圧縮後の正規化振幅を示している。当該正規化振幅は、パルス圧縮前の正規化電力と等価である。
　太線は、図５の太線が示すレーダ信号ｓ（ｍ）における周波数上の電力特性を示している。細線は、Ｈａｍｍｉｎｇ窓である。
　窓関数Ｗ（ｆ（ｍ））として、Ｈａｍｍｉｎｇ窓を用いた場合のレーダ信号ｓ（ｍ）は、図６に示すように、ハミング窓と同様の信号成分を周波数上で得ている。 FIG. 5 is an explanatory diagram showing the time-frequency characteristics of the radar signal s (m) generated by the signal generation unit 13.
In FIG. 5, the horizontal axis represents time and the vertical axis represents frequency.
The thick line shows the time-frequency characteristics of the radar signal s (m) when the Hamming window is used as the window function W (f (m)). The thin line shows the time-frequency characteristics of the linear chirp.
FIG. 6 is an explanatory diagram showing the power characteristics on the frequency of the radar signal s (m) generated by the signal generation unit 13.
In FIG. 6, the horizontal axis represents the frequency and the vertical axis represents the normalized amplitude after pulse compression. The normalized amplitude is equivalent to the normalized power before pulse compression.
The thick line shows the power characteristic on the frequency in the radar signal s (m) shown by the thick line in FIG. The thin line is the Hamming window.
As shown in FIG. 6, the radar signal s (m) when the Hamming window is used as the window function W (f (m)) obtains a signal component similar to that of the humming window on the frequency.
　図７は、パルス圧縮後のレーダ信号ｓ（ｍ）’を示す説明図である。
　図７において、横軸はレンジを示し、縦軸は規格化電力を示している。
　太線は、図５の太線が示すレーダ信号ｓ（ｍ）のパルス圧縮後の信号であるレーダ信号ｓ（ｍ）’を示し、細線は、Ｈａｍｍｉｎｇ窓が施された線形チャープのパルス圧縮後の信号を示している。
　パルス圧縮後のレーダ信号ｓ（ｍ）’は、図７に示すように、Ｈａｍｍｉｎｇ窓が施された線形チャープのパルス圧縮後の信号とほぼ同様の特性が得られている。即ち、パルス圧縮後のレーダ信号ｓ（ｍ）’は、Ｈａｍｍｉｎｇ窓が施された線形チャープのパルス圧縮後の信号と同様に、サイドローブの低減効果が得られている。 FIG. 7 is an explanatory diagram showing a radar signal s (m)'after pulse compression.
In FIG. 7, the horizontal axis represents the range and the vertical axis represents the normalized power.
The thick line indicates the radar signal s (m)'which is the signal after pulse compression of the radar signal s (m) shown by the thick line in FIG. 5, and the thin line is the signal after pulse compression of the linear chirp provided with the Hamming window. Is shown.
As shown in FIG. 7, the radar signal s (m)'after pulse compression has substantially the same characteristics as the signal after pulse compression of a linear chirp provided with a Hamming window. That is, the radar signal s (m)'after pulse compression has a sidelobe reduction effect similar to the signal after pulse compression of the linear chirp provided with the Hamming window.
　信号生成部１３により生成されたレーダ信号ｓ（ｍ）における周波数上の電力分布の形状は、窓関数Ｗ（ｆ（ｍ））と同様の形状となる。したがって、窓関数Ｗ（ｆ（ｍ））が示す形状が、例えば、図８Ａ又は図８Ｂに示すように、単峰型であれば、レーダ信号ｓ（ｍ）における周波数上の電力分布の形状は、単峰型となる。
　窓関数Ｗ（ｆ（ｍ））が示す形状が、例えば、図９Ａ又は図９Ｂに示すように、複峰型であれば、レーダ信号ｓ（ｍ）における周波数上の電力分布の形状は、複峰型となる。
　図８Ａ及び図８Ｂのそれぞれは、形状が単峰型である窓関数Ｗ（ｆ（ｍ））の一例を示す説明図である。
　図９Ａ及び図９Ｂのそれぞれは、形状が複峰型である窓関数Ｗ（ｆ（ｍ））の一例を示す説明図である。
　干渉が発生する観測状況下において、あらかじめ干渉の発生する周波数帯域が分かっている場合、形状が複峰型である窓関数Ｗ（ｆ（ｍ））を用いることによって、干渉の影響を低減した状態での観測が可能になる。即ち、電力が高い２つの周波数帯域の間の周波数帯域に、干渉の発生する周波数帯域を合わせることにより、干渉の影響を低減した状態での観測が可能になる。 The shape of the power distribution on the frequency in the radar signal s (m) generated by the signal generation unit 13 has the same shape as the window function W (f (m)). Therefore, if the shape indicated by the window function W (f (m)) is, for example, a single peak type as shown in FIG. 8A or FIG. 8B, the shape of the power distribution on the frequency in the radar signal s (m) is , Becomes a single peak type.
If the shape indicated by the window function W (f (m)) is, for example, a double peak type as shown in FIG. 9A or FIG. 9B, the shape of the power distribution on the frequency in the radar signal s (m) is double. It becomes a peak type.
Each of FIGS. 8A and 8B is an explanatory diagram showing an example of a window function W (f (m)) having a single peak shape.
Each of FIGS. 9A and 9B is an explanatory diagram showing an example of a window function W (f (m)) having a compound peak shape.
In the observation situation where interference occurs, when the frequency band where interference occurs is known in advance, the influence of interference is reduced by using the window function W (f (m)) whose shape is a compound peak type. Can be observed at. That is, by matching the frequency band where the interference occurs to the frequency band between the two frequency bands having high power, observation in a state where the influence of the interference is reduced becomes possible.
　以上の実施の形態１では、周波数の電力分布に偏りがある非線形チャープパルスにおける周波数の電力特性を用いて、非線形チャープパルスにおける周波数の時間応答を算出する時間応答算出部１２と、時間応答算出部１２により算出された周波数の時間応答と、非線形チャープパルスのサンプリング間隔とを用いて、非線形チャープパルスにおける位相の時間応答を算出し、位相の時間応答を有する非線形チャープパルスを生成する信号生成部１３とを備えるように、信号生成装置１を構成した。したがって、信号生成装置１は、位相の時間応答に誤差が含まれることに伴う、非線形チャープパルスの信号波形の劣化を防ぐことができる。 In the above-described first embodiment, the time response calculation unit 12 and the time response calculation unit 12 that calculate the time response of the frequency in the non-linear charp pulse by using the power characteristic of the frequency in the non-linear chirp pulse having a bias in the power distribution of the frequency. Using the time response of the frequency calculated by 12 and the sampling interval of the non-linear chap pulse, the signal generation unit 13 that calculates the time response of the phase in the non-linear charp pulse and generates the non-linear chap pulse having the time response of the phase. The signal generation device 1 is configured to include the above. Therefore, the signal generation device 1 can prevent deterioration of the signal waveform of the nonlinear chirped pulse due to the inclusion of an error in the time response of the phase.
実施の形態２．
　実施の形態２では、時間応答算出部１４が、非線形チャープパルスにおける周波数の電力特性を用いて、周波数の変化率を算出し、周波数の変化率から非線形チャープパルスにおける周波数の時間応答を算出する信号生成装置１について説明図する。 Embodiment 2.
In the second embodiment, the time response calculation unit 14 calculates the rate of change of the frequency using the power characteristic of the frequency in the non-linear chirp pulse, and calculates the time response of the frequency in the non-linear chirp pulse from the rate of change of the frequency. The generation device 1 will be illustrated.
　図１０は、実施の形態２に係る信号生成装置１を含むレーダシステムを示す構成図である。図１０において、図１と同一符号は同一又は相当部分を示すので説明を省略する。
　図１１は、実施の形態２に係る信号生成装置１のハードウェアを示すハードウェア構成図である。図１１において、図２と同一符号は同一又は相当部分を示すので説明を省略する。 FIG. 10 is a configuration diagram showing a radar system including the signal generation device 1 according to the second embodiment. In FIG. 10, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts, and thus the description thereof will be omitted.
FIG. 11 is a hardware configuration diagram showing the hardware of the signal generation device 1 according to the second embodiment. In FIG. 11, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts, and thus the description thereof will be omitted.
　記憶部２は、電力特性保持部２４、レーダ信号保持部２２及び表示データ保持部２３を備えている。
　電力特性保持部２４は、非線形チャープパルスにおける周波数の電力特性として、非線形チャープパルスにおけるそれぞれの周波数に対応する電力を示す関数Ｒ（ｆ）を保持している。 The storage unit 2 includes a power characteristic holding unit 24, a radar signal holding unit 22, and a display data holding unit 23.
The power characteristic holding unit 24 holds a function R (f) indicating the power corresponding to each frequency in the nonlinear chirped pulse as the power characteristic of the frequency in the nonlinear chirped pulse.
　時間応答算出部１４は、例えば、図１１に示す時間応答算出回路３４によって実現される。
　時間応答算出部１４は、初期値設定部１１から出力された非線形チャープパルスにおけるパルス時間幅Ｔ及びサンプリング間隔Ｄｔのそれぞれを取得する。
　時間応答算出部１４は、電力特性保持部２４により記憶されている関数Ｒ（ｆ）を取得する。
　時間応答算出部１４は、関数Ｒ（ｆ）が示す周波数の電力特性を用いて、周波数の変化率ΔＦｎ／ΔＴｎ（ｎは、１≦ｎ≦Ｎを満たす自然数：Ｎは、３以上の自然数）を算出する。
　時間応答算出部１４は、周波数の変化率ΔＦｎ／ΔＴｎから非線形チャープパルスにおける周波数の時間応答ｆ（ｔ）を算出する。
　時間応答算出部１４は、周波数の時間応答ｆ（ｔ）を信号生成部１３に出力する。 The time response calculation unit 14 is realized by, for example, the time response calculation circuit 34 shown in FIG.
The time response calculation unit 14 acquires each of the pulse time width T and the sampling interval Dt in the nonlinear chirped pulse output from the initial value setting unit 11.
The time response calculation unit 14 acquires the function R (f) stored by the power characteristic holding unit 24.
The time response calculation unit 14 uses the power characteristic of the frequency indicated by the function R (f), and uses the frequency change rate ΔF n / ΔT n (n is a natural number satisfying 1 ≦ n ≦ N: N is 3 or more. Calculate the natural number).
The time response calculation unit 14 calculates the time response f (t) of the frequency in the nonlinear chirped pulse from the rate of change ΔF n / ΔT n of the frequency.
The time response calculation unit 14 outputs the time response f (t) of the frequency to the signal generation unit 13.
　図１０では、信号生成装置１の構成要素である初期値設定部１１、時間応答算出部１４及び信号生成部１３のそれぞれが、図１１に示すような専用のハードウェアによって実現されるものを想定している。即ち、信号生成装置１が、初期値設定回路３１、時間応答算出回路３４及び信号生成回路３３によって実現されるものを想定している。
　初期値設定回路３１、時間応答算出回路３４及び信号生成回路３３のそれぞれは、例えば、単一回路、複合回路、プログラム化したプロセッサ、並列プログラム化したプロセッサ、ＡＳＩＣ、ＦＰＧＡ、又は、これらを組み合わせたものが該当する。 In FIG. 10, it is assumed that each of the initial value setting unit 11, the time response calculation unit 14, and the signal generation unit 13, which are the components of the signal generation device 1, is realized by dedicated hardware as shown in FIG. doing. That is, it is assumed that the signal generation device 1 is realized by the initial value setting circuit 31, the time response calculation circuit 34, and the signal generation circuit 33.
Each of the initial value setting circuit 31, the time response calculation circuit 34, and the signal generation circuit 33 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. The thing is applicable.
　信号生成装置１の構成要素は、専用のハードウェアによって実現されるものに限るものではなく、信号生成装置１が、ソフトウェア、ファームウェア、又は、ソフトウェアとファームウェアとの組み合わせによって実現されるものであってもよい。
　信号生成装置１が、ソフトウェア又はファームウェア等によって実現される場合、初期値設定部１１、時間応答算出部１４及び信号生成部１３におけるそれぞれの処理手順をコンピュータに実行させるためのプログラムが図３に示すメモリ４１に格納される。そして、図３に示すプロセッサ４２がメモリ４１に格納されているプログラムを実行する。 The components of the signal generator 1 are not limited to those realized by dedicated hardware, but the signal generator 1 is realized by software, firmware, or a combination of software and firmware. It is also good.
When the signal generation device 1 is realized by software, firmware, or the like, FIG. 3 shows a program for causing a computer to execute each processing procedure in the initial value setting unit 11, the time response calculation unit 14, and the signal generation unit 13. It is stored in the memory 41. Then, the processor 42 shown in FIG. 3 executes the program stored in the memory 41.
　また、図１１では、信号生成装置１の構成要素のそれぞれが専用のハードウェアによって実現される例を示し、図３では、信号生成装置１がソフトウェア又はファームウェア等によって実現される例を示している。しかし、これは一例に過ぎず、信号生成装置１における一部の構成要素が専用のハードウェアによって実現され、残りの構成要素がソフトウェア又はファームウェア等によって実現されるものであってもよい。 Further, FIG. 11 shows an example in which each of the components of the signal generation device 1 is realized by dedicated hardware, and FIG. 3 shows an example in which the signal generation device 1 is realized by software, firmware, or the like. .. However, this is only an example, and some components in the signal generation device 1 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, or the like.
　次に、図１０に示す信号生成装置１の動作について説明する。
　初期値設定部１１は、式（１）に示すように、非線形チャープパルスの周波数帯域幅Ｂと、オーバーサンプリング率αとから、非線形チャープパルスのサンプリング間隔Ｄｔを設定する。
　初期値設定部１１は、非線形チャープパルスにおけるパルス時間幅Ｔ及びサンプリング間隔Ｄｔのそれぞれを時間応答算出部１４に出力する。 Next, the operation of the signal generation device 1 shown in FIG. 10 will be described.
As shown in the equation (1), the initial value setting unit 11 sets the sampling interval Dt of the nonlinear chirped pulse from the frequency bandwidth B of the nonlinear chirped pulse and the oversampling rate α.
The initial value setting unit 11 outputs each of the pulse time width T and the sampling interval Dt in the nonlinear chirped pulse to the time response calculation unit 14.
　時間応答算出部１４は、初期値設定部１１から出力された非線形チャープパルスにおけるパルス時間幅Ｔ及びサンプリング間隔Ｄｔのそれぞれを取得する。
　時間応答算出部１４は、電力特性保持部２４により記憶されている関数Ｒ（ｆ）を取得する。
　図１２は、関数Ｒ（ｆ）の一例を示す説明図である。
　図１２において、横軸は周波数を示し、縦軸は電力を示している。
　図１２に示す関数Ｒ（ｆ）は、Ｎ個の周波数領域におけるそれぞれの電力を示している。
　Ｒ（ｆ１）＝Ｐ１　　（Ｆ０≦ｆ１＜Ｆ１）
　Ｒ（ｆ２）＝Ｐ２　　（Ｆ１≦ｆ２＜Ｆ２）
　　　　：
　Ｒ（ｆＮ）＝ＰＮ　　（ＦＮ－１≦ｆＮ＜ＦＮ） The time response calculation unit 14 acquires each of the pulse time width T and the sampling interval Dt in the nonlinear chirped pulse output from the initial value setting unit 11.
The time response calculation unit 14 acquires the function R (f) stored by the power characteristic holding unit 24.
FIG. 12 is an explanatory diagram showing an example of the function R (f).
In FIG. 12, the horizontal axis represents frequency and the vertical axis represents electric power.
The function R (f) shown in FIG. 12 shows each power in N frequency domains.
R (f 1 ) = P 1 (F 0 ≤ f 1 <F 1 )
R (f 2 ) = P 2 (F 1 ≤ f 2 <F 2 )
:
R (f N ) = P N (F N-1 ≤ f N <F N )
　時間応答算出部１４は、周波数Ｆｎと周波数Ｆｎ－１との変化量ΔＦｎを算出する。ｎ＝
１，２，・・・，Ｎである。
　ΔＦ１＝Ｆ１－Ｆ０
　ΔＦ２＝Ｆ２－Ｆ１
　　　　：
　ΔＦＮ＝ＦＮ－ＦＮ－１
　図１２では、関数Ｒ（ｆ）が、それぞれの周波数に対応する電力を矩形の形状で表している。変化量ΔＦｎを小さくすれば、それぞれの周波数に対応する電力を所望の形状で表すことができる。 The time response calculation unit 14 calculates the amount of change ΔF n between the frequency F n and the frequency F n-1 . n =
1, 2, ..., N.
ΔF 1 = F 1 −F 0
ΔF 2 = F 2- F 1
:
ΔF N = F N −F N-1
In FIG. 12, the function R (f) represents the electric power corresponding to each frequency in a rectangular shape. By reducing the amount of change ΔF n , the electric power corresponding to each frequency can be expressed in a desired shape.
　次に、時間応答算出部１４は、Ｎ個の周波数領域において、周波数の遷移に要する時間がΔＴｎ（図１３を参照）であるとして、周波数の変化率ΔＦｎ／ΔＴｎを算出する。以下のｃは、任意の定数である。

　ΔＦ１／ΔＴ１＝ｃ／Ｐ１
　ΔＦ２／ΔＴ２＝ｃ／Ｐ２
　　　　：
　ΔＦＮ／ΔＴＮ＝ｃ／ＰＮ

　図１３は、周波数の遷移に要する時間ΔＴｎと、周波数の変化量ΔＦｎとを示す説明図である。
　図１３において、横軸は時間を示し、縦軸は周波数を示している。 Next, the time response calculation unit 14 calculates the frequency change rate ΔF n / ΔT n , assuming that the time required for the frequency transition is ΔT n (see FIG. 13) in the N frequency domains. The following c is an arbitrary constant.

ΔF 1 / ΔT 1 = c / P 1
ΔF 2 / ΔT 2 = c / P 2
:
ΔF N / ΔT N = c / P N

FIG. 13 is an explanatory diagram showing the time ΔT n required for the frequency transition and the frequency change amount ΔF n.
In FIG. 13, the horizontal axis represents time and the vertical axis represents frequency.
　図１３の例では、周波数の遷移に要する時間のそれぞれがΔＴ１～ΔＴＮであり、ΔＴ１～ΔＴＮの合計の時間が、非線形チャープパルスのパルス時間幅Ｔである。以下に示す式（１５）～式（１７）が成立する。

Figure JPOXMLDOC01-appb-I000011
　したがって、周波数の変化率ΔＦｎ／ΔＴｎであるチャープレートγｎは、以下の式（１８）のように表される。

Figure JPOXMLDOC01-appb-I000012
In the example of FIG. 13, each of the time required for the transition frequency is ΔT 1 ~ ΔT N, the total time of ΔT 1 ~ ΔT N is the pulse time width T of the nonlinear chirp pulse. The following equations (15) to (17) are established.

Figure JPOXMLDOC01-appb-I000011
Therefore, the char plate γ n having the frequency change rate ΔF n / ΔT n is expressed by the following equation (18).

Figure JPOXMLDOC01-appb-I000012
　時間応答算出部１４は、以下の式（１９）に示すように、周波数の変化率ΔＦｎ／ΔＴｎであるチャープレートγｎから、非線形チャープパルスにおける周波数の時間応答ｆ（ｔ）を算出する。

Figure JPOXMLDOC01-appb-I000013
　時間応答算出部１４は、周波数の時間応答ｆ（ｔ）及びサンプリング間隔Ｄｔのそれぞれを信号生成部１３に出力する。 As shown in the following equation (19), the time response calculation unit 14 calculates the time response f (t) of the frequency in the nonlinear chirped pulse from the char plate γ n having the frequency change rate ΔF n / ΔT n. ..

Figure JPOXMLDOC01-appb-I000013
The time response calculation unit 14 outputs each of the frequency time response f (t) and the sampling interval Dt to the signal generation unit 13.
　信号生成部１３は、時間応答算出部１４から出力された周波数の時間応答ｆ（ｔ）及びサンプリング間隔Ｄｔのそれぞれを取得する。
　信号生成部１３は、以下の式（２０）に示すように、周波数の時間応答ｆ（ｔ）及びサンプリング間隔Ｄｔのそれぞれを用いて、位相の変化量Ｄｐ（ｇ）を算出する。

Figure JPOXMLDOC01-appb-I000014
The signal generation unit 13 acquires each of the time response f (t) of the frequency output from the time response calculation unit 14 and the sampling interval Dt.
As shown in the following equation (20), the signal generation unit 13 calculates the phase change amount D p (g) using each of the frequency time response f (t) and the sampling interval Dt.

Figure JPOXMLDOC01-appb-I000014
　信号生成部１３は、以下の式（２１）に示す位相の時間応答の初期値ｐ（０）に、位相の変化量Ｄｐ（ｇ）を加算することによって、位相の時間応答ｐ（ｇ）を算出する。

Figure JPOXMLDOC01-appb-I000015
 The signal generation unit 13 adds the phase change amount D p (g) to the initial value p (0) of the phase time response shown in the following equation (21) to obtain the phase time response p (g). Is calculated.

Figure JPOXMLDOC01-appb-I000015
　信号生成部１３は、以下の式（２３）に示すように、レーダ信号ｓ（ｍ）として、位相の時間応答ｐ（ｇ）を有する非線形チャープパルスを生成する。

Figure JPOXMLDOC01-appb-I000016
　信号生成部１３は、生成した非線形チャープパルスをレーダ信号ｓ（ｍ）として、記憶部２のレーダ信号保持部２２に出力する。 As shown in the following equation (23), the signal generation unit 13 generates a non-linear chirped pulse having a phase time response p (g) as the radar signal s (m).

Figure JPOXMLDOC01-appb-I000016
The signal generation unit 13 outputs the generated nonlinear chirped pulse as a radar signal s (m) to the radar signal holding unit 22 of the storage unit 2.
　以上の実施の形態２では、時間応答算出部１４が、非線形チャープパルスにおける周波数の電力特性を用いて、周波数の変化率を算出し、周波数の変化率から非線形チャープパルスにおける周波数の時間応答を算出するように、図１０に示す信号生成装置１を構成した。したがって、図１０に示す信号生成装置１は、図１に示す信号生成装置１と同様に、位相の時間応答に誤差が含まれることに伴う、非線形チャープパルスの信号波形の劣化を防ぐことができる。 In the second embodiment, the time response calculation unit 14 calculates the rate of change of the frequency using the power characteristic of the frequency in the non-linear chirp pulse, and calculates the time response of the frequency in the non-linear chirp pulse from the rate of change of the frequency. As such, the signal generation device 1 shown in FIG. 10 was configured. Therefore, the signal generation device 1 shown in FIG. 10 can prevent deterioration of the signal waveform of the nonlinear chirped pulse due to the inclusion of an error in the time response of the phase, similarly to the signal generation device 1 shown in FIG. ..
　なお、本開示は、各実施の形態の自由な組み合わせ、あるいは各実施の形態の任意の構成要素の変形、もしくは各実施の形態において任意の構成要素の省略が可能である。 In the present disclosure, it is possible to freely combine the embodiments, modify any component of each embodiment, or omit any component in each embodiment.
　本開示は、非線形チャープパルスを生成する信号生成装置、信号生成方法及び信号生成プログラムに適している。 The present disclosure is suitable for a signal generator, a signal generation method, and a signal generation program that generate a non-linear chirped pulse.
　１　信号生成装置、２　記憶部、３　レーダ信号処理部、４　レーダ部、５　表示部、１１　初期値設定部、１２　時間応答算出部、１３　信号生成部、１４　時間応答算出部、２１　窓関数保持部、２２　レーダ信号保持部、２３　表示データ保持部、２４　電力特性保持部、３１　初期値設定回路、３２　時間応答算出回路、３３　信号生成回路、３４　時間応答算出回路、４１　メモリ、４２　プロセッサ。 1 signal generator, 2 storage unit, 3 radar signal processing unit, 4 radar unit, 5 display unit, 11 initial value setting unit, 12 time response calculation unit, 13 signal generation unit, 14 time response calculation unit, 21 window function holding Unit, 22 radar signal holding unit, 23 display data holding unit, 24 power characteristic holding unit, 31 initial value setting circuit, 32 time response calculation circuit, 33 signal generation circuit, 34 time response calculation circuit, 41 memory, 42 processor.

Claims (7)

  1. 　周波数の電力分布に偏りがある非線形チャープパルスにおける周波数の電力特性を用いて、前記非線形チャープパルスにおける周波数の時間応答を算出する時間応答算出部と、
    　前記時間応答算出部により算出された周波数の時間応答と、前記非線形チャープパルスのサンプリング間隔とを用いて、前記非線形チャープパルスにおける位相の時間応答を算出し、前記位相の時間応答を有する非線形チャープパルスを生成する信号生成部と
    　を備えた信号生成装置。     A time response calculation unit that calculates the time response of the frequency in the nonlinear chirped pulse using the power characteristics of the frequency in the nonlinear chirped pulse whose frequency power distribution is biased.
    Using the time response of the frequency calculated by the time response calculation unit and the sampling interval of the non-linear chap pulse, the time response of the phase in the non-linear chap pulse is calculated, and the non-linear chap pulse having the time response of the phase is obtained. A signal generator equipped with a signal generator that generates a signal.
  2. 　前記時間応答算出部は、
    　前記非線形チャープパルスにおける周波数の電力特性を用いて、前記サンプリング間隔の間に変化している周波数の変化量を算出し、前記周波数の変化量から前記非線形チャープパルスにおける周波数の時間応答を算出することを特徴とする請求項１記載の信号生成装置。     The time response calculation unit
    Using the power characteristics of the frequency in the nonlinear chirp pulse, the amount of change in the frequency changing during the sampling interval is calculated, and the time response of the frequency in the nonlinear chirp pulse is calculated from the amount of change in the frequency. The signal generator according to claim 1.
  3. 　前記時間応答算出部は、
    　前記非線形チャープパルスにおける周波数の電力特性を用いて、前記周波数の変化率を算出し、前記周波数の変化率から前記非線形チャープパルスにおける周波数の時間応答を算出することを特徴とする請求項１記載の信号生成装置。     The time response calculation unit
    The first aspect of the present invention, wherein the rate of change of the frequency is calculated by using the power characteristic of the frequency in the non-linear chap pulse, and the time response of the frequency in the non-linear charp pulse is calculated from the rate of change of the frequency. Signal generator.
  4. 　前記非線形チャープパルスにおける周波数の電力特性が示す電力分布の形状が、単峰型であることを特徴とする請求項１記載の信号生成装置。 The signal generation device according to claim 1, wherein the shape of the power distribution indicated by the power characteristic of the frequency in the nonlinear chirped pulse is a single peak type.
  5. 　前記非線形チャープパルスにおける周波数の電力特性が示す電力分布の形状が、複峰型であることを特徴とする請求項１記載の信号生成装置。 The signal generation device according to claim 1, wherein the shape of the power distribution indicated by the power characteristic of the frequency in the nonlinear chirped pulse is a compound peak type.
  6. 　時間応答算出部が、周波数の電力分布に偏りがある非線形チャープパルスにおける周波数の電力特性を用いて、前記非線形チャープパルスにおける周波数の時間応答を算出し、
    　信号生成部が、前記時間応答算出部により算出された周波数の時間応答と、前記非線形チャープパルスのサンプリング間隔とを用いて、前記非線形チャープパルスにおける位相の時間応答を算出し、前記位相の時間応答を有する非線形チャープパルスを生成する
    　信号生成方法。     The time response calculation unit calculates the time response of the frequency in the non-linear chirped pulse by using the power characteristic of the frequency in the non-linear chirped pulse having a bias in the power distribution of the frequency.
    The signal generation unit calculates the time response of the phase in the non-linear charp pulse by using the time response of the frequency calculated by the time response calculation unit and the sampling interval of the non-linear charp pulse, and the time response of the phase. A signal generation method that produces a non-linear chap pulse with.
  7. 　時間応答算出部が、周波数の電力分布に偏りがある非線形チャープパルスにおける周波数の電力特性を用いて、前記非線形チャープパルスにおける周波数の時間応答を算出する処理手順と、
    　信号生成部が、前記時間応答算出部により算出された周波数の時間応答と、前記非線形チャープパルスのサンプリング間隔とを用いて、前記非線形チャープパルスにおける位相の時間応答を算出し、前記位相の時間応答を有する非線形チャープパルスを生成する処理手順と
    　をコンピュータに実行させるための信号生成プログラム。     A processing procedure in which the time response calculation unit calculates the time response of the frequency in the non-linear chap pulse using the power characteristic of the frequency in the non-linear chap pulse having a bias in the power distribution of the frequency.
    The signal generation unit calculates the time response of the phase in the non-linear charp pulse by using the time response of the frequency calculated by the time response calculation unit and the sampling interval of the non-linear charp pulse, and the time response of the phase. A signal generation program for causing a computer to perform a processing procedure to generate a non-linear chap pulse with.
PCT/JP2020/017602 2020-04-24 2020-04-24 Signal generation device, signal generation method, and signal generation program WO2021214960A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004077775A1 (en) * 2003-02-25 2004-09-10 Yokohama Tlo Company, Ltd. Pulse waveform producing method
US7880672B1 (en) * 2007-09-17 2011-02-01 Sandia Corporation Generating nonlinear FM chirp radar signals by multiple integrations
JP2011038948A (en) * 2009-08-14 2011-02-24 Tokyo Keiki Inc Transmission waveform generation method in pulse compression, transmission waveform generation program, and pulse compression device manufactured by the transmission waveform generation method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004077775A1 (en) * 2003-02-25 2004-09-10 Yokohama Tlo Company, Ltd. Pulse waveform producing method
US7880672B1 (en) * 2007-09-17 2011-02-01 Sandia Corporation Generating nonlinear FM chirp radar signals by multiple integrations
JP2011038948A (en) * 2009-08-14 2011-02-24 Tokyo Keiki Inc Transmission waveform generation method in pulse compression, transmission waveform generation program, and pulse compression device manufactured by the transmission waveform generation method

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