Radar signal processing device, radar device, radar signal processing method, and radar signal processing program

Abstract

To detect targets more accurately based on beat signals.SOLUTION: A radar signal processing device includes: an extracted signal generation unit that generates a plurality of extraction beat signals extracted based on a plurality of different time ranges from a processing signal generated based on a beat signal of a transmission signal and a reception signal; a conversion unit that converts the plurality of extraction beat signals into amplitude data indicating a relation between a distance and an amplitude; and an integrated data generation unit that generates integrated data obtained by integrating the plurality of amplitude data.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a radar signal processing device, a radar device, a radar signal processing method, and a radar signal processing program. [Background technology]

[0002] Conventionally, a technique for removing interference waves from a beat signal is known. For example, Patent Document 1 (US Pat. No. 9,442,191) discloses a radar system as follows. That is, in each of a first signal processing path and a second signal processing path which are parallel signal processing circuits, the radar system removes interference from a copy of a beat signal, selects at least one window function from a plurality of window functions having different frequency responses and applies it to the beat signal, and converts the beat signal from the time domain to the frequency domain. Then, the radar system combines the output of the first signal processing path and the output of the second signal processing path to generate an output beat signal. Here, in each of the first signal processing path and the second signal processing path in the radar system, an interference removal method and a window function different from those of the other parallel signal processing paths are applied. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 9,442,191 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, by removing interference waves from a beat signal, the range side lobes in the power spectrum generated based on the beat signal increase, and there are cases in which it is not possible to accurately detect a target. There is a demand for a technology that goes beyond the technology described in Patent Document 1 and is capable of detecting a target based on a beat signal more accurately.

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a radar signal processing device, a radar device, a radar signal processing method, and a radar signal processing program that are capable of more accurately detecting a target based on a beat signal. [Means for solving the problem]

[0006] In order to solve the above problem, a radar signal processing device according to an aspect of the present invention includes an extracted signal generation unit that generates a plurality of extracted beat signals extracted based on a plurality of different time ranges from a processed signal generated on the basis of a beat signal between a transmitted signal and a received signal, a conversion unit that converts the plurality of extracted beat signals into amplitude data indicating the relationship between distance and amplitude, and an integrated data generation unit that generates integrated data by integrating the plurality of amplitude data.

[0007] In this way, a configuration is configured to generate a plurality of extracted beat signals extracted based on a plurality of different time ranges from a processed signal based on a beat signal, convert each of the extracted beat signals into amplitude data, and generate integrated data by integrating the plurality of amplitude data, so that the integrated data can be generated using amplitude data based on extracted beat signals that do not include beat signals whose amplitudes have been replaced with zero to remove interference components, thereby suppressing an increase in range side lobes in the integrated data caused by replacing the amplitude of a portion of the beat signals with zero, and making it possible to more accurately detect targets based on integrated data with small range side lobes.As a result, it is possible to more accurately detect targets based on beat signals. Effect of the Invention

[0008] According to the present invention, a target can be detected more accurately based on a beat signal. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a configuration of a radar device according to an embodiment of the present invention. [Diagram 2]FIG. 2 is a diagram showing a configuration of a signal processing unit in the radar device according to the embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing a configuration of a window function / FFT processing unit in the signal processing unit according to the embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing an example of a beat signal that the window function / FFT processor in the signal processor according to the embodiment of the present invention receives from the interference remover. [Diagram 5] FIG. 5 is a diagram showing an example of a beat signal that the window function / FFT processor in the signal processor according to the embodiment of the present invention receives from the interference remover. [Figure 6] FIG. 6 is a diagram showing an example of a window function used in the window function / FFT processing section of the signal processing section according to the embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing an example of amplitude data generated in the window function / FFT processing unit of the signal processing unit according to the embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing an example of integrated data generated in the window function / FFT processing unit of the signal processing unit according to the embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing an example of integrated data generated in the window function / FFT processing unit of the signal processing unit according to the embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing an example of integrated data generated in the window function / FFT processing unit of the signal processing unit according to the embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing an example of integrated data generated in the window function / FFT processing unit of the signal processing unit according to the embodiment of the present invention. [Figure 12] FIG. 12 is a flowchart defining an example of an operation procedure when the radar device according to the embodiment of the present invention generates integrated data. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference characters and their description will not be repeated. In addition, at least some of the embodiments described below may be arbitrarily combined.

[0011] [Configuration and basic operation] <Radar device> FIG. 1 is a diagram showing a configuration of a radar device according to an embodiment of the present invention.

[0012] 1, the radar device 300 includes a radar unit 201 and a display processing unit 202. The radar unit 201 includes a signal generating unit 110, a transmitting unit 120, a transmitting antenna 130, a receiving antenna 140, a receiving unit 150, a mixer unit 160, an A / D (Analog to Digital) conversion unit 170, and a signal processing unit 100. The signal processing unit 100 is an example of a radar signal processing device. For example, the radar device 300 is an FM-CW (Frequency Modulated Continuous Wave) radar device and is mounted on a ship. The radar device 300 performs a process of displaying, on a display device (not shown), an echo image indicating the presence or absence of a target in a detection target area that is an area monitored by the ship and the distance between the radar device 300 and the target.

[0013] The radar unit 201 outputs echo data indicating the detection result of a target in a divided target area, which is a region obtained by dividing the detection target area into a plurality of areas, to the display processing unit 202. The transmitting antenna 130 and the receiving antenna 140 rotate so that the azimuth angle of the radiation direction of radio waves from the transmitting antenna 130 changes by a predetermined angle for each predetermined sweep period T. The radar unit 201 outputs the echo data in each of the plurality of divided target areas for each sweep period T to the display processing unit 202.

[0014] The display processing unit 202 performs processing for displaying an echo image in the detection target area on a display device based on the multiple echo data received from the radar unit 201 .

[0015] <Radar section> The signal generating unit 110 repeatedly generates an analog signal of a predetermined pattern and outputs it to the transmitting unit 120. More specifically, the signal generating unit 110 outputs to the transmitting unit 120, during a sweep period T, an analog signal whose frequency increases by a predetermined amount per unit time, the analog signal having been generated using, for example, an FM-CW modulation method. Specifically, for example, the signal generating unit 110 includes a voltage generating unit and a VCO (Voltage-Controlled Oscillator). During the sweep period T, the voltage generating unit generates an FM modulated voltage whose magnitude increases at a constant rate and outputs it to the VCO. The VCO generates an analog signal having a frequency according to the magnitude of the FM modulated voltage received from the voltage generating unit and outputs it to the transmitting unit 120.

[0016] The transmitting unit 120 transmits a transmission signal. More specifically, during a sweep period T, the transmitting unit 120 generates a transmission signal in the RF (Radio Frequency) band based on an analog signal received from the signal generating unit 110, and outputs the generated transmission signal in the RF band to the division target area via the transmitting antenna 130 that rotates with the rotation of the radar unit 201. The transmitting unit 120 also outputs the generated transmission signal in the RF band to the mixer unit 160. Specifically, for example, the transmitting unit 120 includes a mixer and a power amplifier. The mixer generates a transmission signal in the RF band based on the analog signal received from the signal generating unit 110, and outputs the generated transmission signal to the power amplifier and the mixer unit 160. In the transmitting unit 120, the power amplifier amplifies the transmission signal received from the mixer, and outputs the amplified transmission signal to the division target area via the transmitting antenna 130.

[0017] The receiving unit 150 receives a reflected signal, which is a signal obtained by reflecting a transmission signal from a target object. More specifically, the receiving unit 150 receives a reflected signal in the RF band, which is a signal obtained by reflecting a transmission signal transmitted from the transmitting antenna 130 from a target object in the division target area, via the receiving antenna 140 that rotates with the rotation of the radar unit 201. The receiving unit 150 may also receive an interference wave transmitted by an interfering object via the receiving antenna 140. The interfering object may be, for example, a pulse radar device located within or outside the division target area. The receiving unit 150 outputs a signal received via the receiving antenna 140 to the mixer unit 160. Specifically, for example, the receiving unit 150 includes a low-noise amplifier. The low-noise amplifier amplifies the RF band received signal received via the receiving antenna 140, and outputs the amplified received signal to the mixer unit 160.

[0018] The mixer unit 160 generates a beat signal between the transmission signal transmitted from the radar device 300 and the reception signal received by the radar device 300. Here, the beat signal is a signal having a frequency component that is the difference between the frequency component of the transmission signal transmitted by the transmitter unit 120 and the frequency component of the reception signal received by the receiver unit 150. More specifically, the mixer unit 160 includes, for example, two mixers. A branching unit (not shown) branches the transmission signal output from the transmitter unit 120 and outputs the branched transmission signal to each mixer in the mixer unit 160 after imparting a phase difference of 90° to the branched transmission signal. In addition, a branching unit (not shown) branches the reception signal output from the receiver unit 150 and outputs the branched reception signal to each mixer in the mixer unit 160. The two mixers in the mixer unit 160 multiply the transmission signal and the reception signal, respectively, to generate an analog beat signal SA consisting of a set of an I signal Si and a Q signal Sq, and output the analog beat signal SA to the A / D conversion unit 170.

[0019] The A / D conversion unit 170 converts the analog beat signal SA received from the mixer unit 160 into a beat signal SD, which is a digital signal consisting of a set of I signals Si and Q signals Sq. More specifically, the A / D conversion unit 170 generates N beat signals SD consisting of a set of N I signals Si and N Q signals Sq by performing sampling at a predetermined sampling frequency for each sweep period T, and outputs the N beat signals SD to the signal processing unit 100. N is an integer equal to or greater than 2.

[0020] The signal processing unit 100 processes the N beat signals SD received from the A / D conversion unit 170 in each sweep period T to generate echo data indicating the detection result of the target in the divided target area for each sweep period T. The signal processing unit 100 outputs the generated echo data to the display processing unit 202. Hereinafter, the beat signal SD with sample number n received by the signal processing unit 100 from the A / D conversion unit 170 in the sweep period T is also referred to as beat signal SD(n). n is an integer greater than or equal to 1 and less than or equal to N, and corresponds to the elapsed time from the start of the sweep period T. The beat signal SD(n) is a signal consisting of a set of an I signal Si(n) with sample number n and a Q signal Sq(n) with sample number n.

[0021] The radar device 300 may be configured to include one antenna that functions as the transmitting antenna 130 and the receiving antenna 140, instead of the transmitting antenna 130 and the receiving antenna 140. In this case, for example, the transmitting unit 120 transmits a transmission signal to the transmitting antenna 130 via a circulator. Also, for example, the receiving unit 150 receives a reception signal from the receiving antenna 140 via a circulator.

[0022] <Display processing section> The display processing unit 202 generates integrated data, which is the echo data in the detection target area, based on the echo data for each divided target area received from the signal processing unit 100, and performs processing to display an echo image in the detection target area on a display device (not shown) based on the generated integrated data.

[0023] <Signal processing section> 2 is a diagram showing a configuration of a signal processing unit in a radar device according to an embodiment of the present invention. Referring to Fig. 2, a signal processing unit 100 includes an interference removal unit 20, a window function / FFT (Fast Fourier Transform) processing unit 30, and an absolute value / logarithm conversion unit 40.

[0024] The interference removal unit 20 receives N beat signals SD from the A / D conversion unit 170 for each sweep period T, and performs FFT pre-processing to remove interference components, which are components based on interference waves, from the components of the received beat signals SD. For example, when the interference removal unit 20 detects a beat signal SD(n) containing an interference wave in the FFT pre-processing, it replaces the amplitudes of the I signal Si(n) and the Q signal Sq(n) in the beat signal SD(n) containing the interference wave with zero to remove the interference components. The interference removal unit 20 outputs the beat signal SD(n) after the FFT pre-processing to the window function / FFT processing unit 30.

[0025] The window function / FFT processing unit 30 performs window function processing for multiplying the N beat signals SD(n) after FFT pre-processing received from the interference removal unit 20 by a predetermined window function for each sweep period T, and generates integrated data DI by performing processing such as FFT processing on the beat signals SD(n) after window function processing. The window function / FFT processing unit 30 outputs the generated integrated data DI to the absolute value / logarithm conversion unit 40. Details of the window function processing and FFT processing by the window function / FFT processing unit 30 will be described later.

[0026] The absolute value / logarithm converter 40 generates echo data by logarithmically converting the absolute value of the integrated data DI received from the window function / FFT processor 30 , and outputs the generated echo data to the display processor 202 .

[0027] <Window function / FFT processing section> Fig. 3 is a diagram showing a configuration of a window function / FFT processing unit in a signal processing unit according to an embodiment of the present invention. With reference to Fig. 3, window function / FFT processing unit 30 includes an extracted signal generating unit 31, a transforming unit 32, and an integrated data generating unit 33. Extracted signal generating unit 31 includes window function processing units 31A, 31B, and 31C. Transforming unit 32 includes FFT processing units 32A, 32B, and 32C.

[0028] (Extraction signal generation section) The extracted signal generating unit 31 generates a plurality of extracted beat signals E extracted based on a plurality of different time ranges from a processed signal generated based on a beat signal. For example, based on a beat signal SD(n) in a target time region Ta, the extracted signal generating unit 31 generates a plurality of extracted beat signals E each based on the beat signal SD(n) in a plurality of different time ranges in the target time region Ta. The beat signal SD(n) in the target time region Ta is an example of a processed signal.

[0029] More specifically, each of the window function processing units 31A, 31B, and 31C receives a beat signal SD(n) from the interference removal unit 20, and generates an extracted beat signal E based on a beat signal SD(n) of a predetermined target time region Ta, which is a part or all of the received beat signal SD(n). As an example, each of the window function processing units 31A, 31B, and 31C generates an extracted beat signal E consisting of a set of an extracted I signal Ei and an extracted Q signal Eq, based on the beat signal SD(n) of the target time region Ta, which is all of the N beat signals SD(n) received from the interference removal unit 20.

[0030] Here, the window function processing units 31A, 31B, and 31C may receive from the interference removal unit 20, as the beat signal SD(n) from which the interference components have been removed, for example, a beat signal SD(n) in which the amplitudes of some of the I signals Si(n) and Q signals Sq(n) have been replaced with zero.

[0031] Figures 4 and 5 are diagrams showing an example of a beat signal received from an interference removal section by a window function / FFT processing section in a signal processing section according to an embodiment of the present invention. Figure 5 is an enlarged view of region R1 in Figure 4. In Figures 4 and 5, the horizontal axis represents the value of sample number n of beat signal SD(n), and the vertical axis represents amplitude. The solid lines in Figures 4 and 5 indicate the I signal Si(n) in beat signal SD(n). The dashed lines in Figures 4 and 5 indicate the Q signal Sq(n) in beat signal SD(n).

[0032] 4 and 5, as an example, window function processing units 31A, 31B, and 31C receive from interference removal unit 20 beat signal SD(n) in which the amplitudes of I signal Si(n) and Q signal Sq(n) with sample numbers n of 170 to 175 have been replaced with zero.

[0033] For example, the window function processing units 31A, 31B, and 31C perform window function processing on the beat signal SD(n) received from the interference removal unit 20. Each of the window function processing units 31A, 31B, and 31C generates a plurality of extracted beat signals E by multiplying the beat signal SD(n) by a plurality of window functions Wf having different pass time domains. That is, in the window function processing, each of the window function processing units 31A, 31B, and 31C generates the extracted beat signal E by multiplying the N beat signals SD(n) received from the interference removal unit 20 by window functions Wf having mutually different pass time domains TP, which are the time domains serving as the pass bands.

[0034] More specifically, the window function processing unit 31A generates an extracted beat signal EA, which is an extracted beat signal E consisting of a pair of an extracted I signal EiA and an extracted Q signal EqA, by multiplying the I signal Si(n) and the Q signal Sq(n) in the beat signal SD(n) by a window function WfA.

[0035] In addition, the window function processing unit 31B generates an extracted beat signal EB, which is an extracted beat signal E consisting of a pair of an extracted I signal EiB and an extracted Q signal EqB, by multiplying the I signal Si(n) and the Q signal Sq(n) in the beat signal SD(n) by a window function WfB.

[0036] In addition, the window function processing unit 31C generates an extracted beat signal EC, which is an extracted beat signal E consisting of a pair of an extracted I signal EiC and an extracted Q signal EqC, by multiplying the I signal Si(n) and the Q signal Sq(n) in the beat signal SD(n) by a window function WfC.

[0037] FIG. 6 is a diagram showing an example of a window function used in the window function / FFT processing unit of the signal processing unit according to the embodiment of the present invention. In FIG. 6, the horizontal axis is the value of sample number n of the beat signal SD(n), and the vertical axis is the window weight of the window function Wf. As described above, the sample number n corresponds to the elapsed time from the start of the sweep period T. The solid line in FIG. 6 indicates the window function WfA used in the window function processing by the window function processing unit 31A. The dashed line in FIG. 6 indicates the window function WfB used in the window function processing by the window function processing unit 31B. The dashed line in FIG. 6 indicates the window function WfC used in the window function processing by the window function processing unit 31C.

[0038] Referring to FIG. 6, the passing time domain TPA, which is the passing time domain TP of the window function WfA, is the time from time t0 corresponding to sample number n=zero to time tN corresponding to sample number n=N. The passing time domain TPB, which is the passing time domain TP of the window function WfB, is the time from time t0 corresponding to sample number n=zero to time tk corresponding to sample number n=k. The passing time domain TPC, which is the passing time domain TP of the window function WfC, is the time from time t(k+1) corresponding to sample number n=(k+1) to time tN corresponding to sample number n=N. Here, k is an integer equal to or greater than 2 and less than N, for example, an integer closest to N / 2. That is, the passing time domains TPA, TPB, and TPC correspond to the entire time domain of the target time domain Ta, the first half of the target time domain Ta, and the second half of the target time domain Ta, respectively. For example, the multiple window functions Wf include those having the same shape design. In the example shown in Fig. 6, the window functions WfB and WfC have the same shape in the passing time domains TPB and TPC. Note that the shapes of the window functions WfA, WfB, and WfC are not limited to those shown in Fig. 6 and may be other shapes.

[0039] For example, the extracted signal generating unit 31 generates a plurality of extracted beat signals E extracted based on a temporally continuous time range. That is, the extracted signal generating unit 31 generates a plurality of extracted beat signals E each based on a beat signal (n) in a plurality of temporally continuous time ranges. More specifically, a passing time domain TPB, which is the time from time t0 to time tk, and a passing time domain TPC, which is the time from time t(k+1) to time tN, are temporally continuous time domains in this order. The window function processing units 31B and 31C multiply the beat signal SD(n) by window functions WfB and WfC, respectively, to generate extracted beat signals EB and EC each based on a beat signal (n) in a plurality of temporally continuous time ranges.

[0040] For example, the extracted signal generating unit 31 generates an extracted beat signal E extracted based on a time range including a plurality of time ranges as one of the extracted beat signals E. That is, the extracted signal generating unit 31 generates an extracted beat signal E based on a beat signal SD(n) of the target time region Ta as one of the plurality of extracted beat signals E. More specifically, the passing time region TPA is a time region corresponding to the target time region Ta. The window function processing unit 31A generates an extracted beat signal EA based on the beat signal SD(n) of the target time region Ta by multiplying the beat signal SD(n) by a window function WfA.

[0041] For example, the passing time domains TPA and TPB include times when sample number n corresponds to 170 to 175, while the passing time domain TPC does not include times when sample number n corresponds to 170 to 175. In other words, the extracted beat signals EA and EB include the I signal Si(n) and the Q signal Sq(n) whose amplitudes have been replaced with zero, while the extracted beat signal EC does not include the I signal Si(n) and the Q signal Sq(n) whose amplitudes have been replaced with zero.

[0042] The window function processing units 31A, 31B, and 31C output the generated extracted beat signals EA, EB, and EC to the FFT processing units 32A, 32B, and 32C in the conversion unit 32, respectively.

[0043] (Conversion section) The converter 32 converts the extracted beat signals E into amplitude data DS indicating the relationship between distance and amplitude. That is, the converter 32 converts each of the extracted beat signals E, which are complex signals, into amplitude data DS indicating the relationship between the distance d from the radar device 300 and the amplitude.

[0044] More specifically, the conversion unit 32 receives a plurality of extracted beat signals E from the extraction signal generation unit 31, and generates a power spectrum P, which is a complex signal, by performing FFT processing on the received extracted beat signals E. The conversion unit 32 then performs processing such as multiplying the frequency in each power spectrum P generated for each extracted beat signal E by a coefficient C to convert the frequency into a distance d, thereby generating amplitude data DS, which is a complex signal, for each extracted beat signal E.

[0045] Specifically, the FFT processing unit 32A receives the extracted beat signal EA from the window function processing unit 31A, and performs FFT processing on the received extracted beat signal EA to generate a power spectrum PA. The FFT processing unit 32A then multiplies the frequency in the generated power spectrum PA by a coefficient C to convert the frequency into a distance d, thereby generating amplitude data DSA indicating the relationship between the distance d and the amplitude.

[0046] Furthermore, the FFT processing unit 32B receives the extracted beat signal EB from the window function processing unit 31B, and performs FFT processing on the received extracted beat signal EB to generate a power spectrum PB. The FFT processing unit 32B then multiplies the frequency in the generated power spectrum PB by a coefficient C to convert the frequency into a distance d, and performs processing to double the I data and Q data in the power spectrum PB, respectively, to generate amplitude data DSB indicating the relationship between the distance d and the amplitude. Here, since the passing time domain TPB of the window function WfB is 1 / 2 the passing time domain TPA of the window function WfA, the output of the power spectrum PB is 1 / 2 the power spectrum PA. Therefore, the FFT processing unit 32B performs processing to double the I data and Q data in the power spectrum PB in order to compensate for the ratio of the power spectrum P caused by the ratio of the passing time domain TP of the window function Wf. For example, when the passing time domain TPB of the window function WfB is 1 / K of the passing time domain TPA of the window function WfA, the FFT processing unit 32B performs a process of multiplying the I data and Q data in the power spectrum PB by K in order to compensate for the ratio between the output of the power spectrum PB and the power spectrum PA.

[0047] Furthermore, the FFT processing unit 32C receives the extracted beat signal EC from the window function processing unit 31C, and performs FFT processing on the received extracted beat signal EC to generate a power spectrum PC. The FFT processing unit 32C then multiplies the frequency in the generated power spectrum PC by a coefficient C to convert the frequency into a distance d, and, similarly to the FFT processing unit 32B, doubles each of the I data and Q data in the power spectrum PC to generate amplitude data DSC indicating the relationship between the distance d and the amplitude.

[0048] Fig. 7 is a diagram showing an example of amplitude data generated in a window function / FFT processing unit of a signal processing unit according to an embodiment of the present invention. In Fig. 7, the horizontal axis is distance d [m], and the vertical axis is amplitude [dB]. The dashed line in Fig. 7 indicates amplitude Xa of the amplitude data DSA. The dashed line in Fig. 7 indicates amplitude Xb of the amplitude data DSB. The two-dot chain line in Fig. 7 indicates amplitude Xc of the amplitude data DSC.

[0049] 7, the amplitude data DSC has smaller range side lobes than the amplitude data DSA and DSB, because, as described above, the extracted beat signals EA and EB include the I signal Si(n) and the Q signal Sq(n) whose amplitudes have been replaced with zero, while the extracted beat signal EC does not include the I signal Si(n) and the Q signal Sq(n) whose amplitudes have been replaced with zero.

[0050] The FFT processing units 32A, 32B, and 32C output the generated amplitude data DSA, DSB, and DSC to the integrated data generating unit 33, respectively.

[0051] (Integrated Data Generation Division) The integrated data generating unit 33 generates integrated data by integrating a plurality of amplitude data. More specifically, the integrated data generating unit 33 generates integrated data DI indicating a relationship between the distance d and the amplitude based on the amplitude for each distance d in the amplitude data DSA, DSB, and DSC.

[0052] For example, the integrated data generating unit 33 generates the integrated data DI by selecting one of the amplitude data DSA, DSB, and DSC for each distance d. As an example, the integrated data generating unit 33 takes the minimum value of the amplitude data DSA, DSB, and DSC to generate the integrated data DI, which is a collection of the minimum values ​​of the amplitude data DSA, DSB, and DSC.

[0053] More specifically, the integrated data generation unit 33 calculates the amplitude absolute value ampA(d) for each distance d of the amplitude data DSA represented by the following equation (1), the amplitude absolute value ampB(d) for each distance d of the amplitude data DSB represented by the following equation (2), and the amplitude absolute value ampC(d) for each distance d of the amplitude data DSC represented by the following equation (3). ampA(d)=(Ia)^2+(Qa)^2 ··· (1) ampB(d)=(Ib)^2+(Qb)^2 ··· (2) ampC(d)=(Ic)^2+(Qc)^2 ··· (3)

[0054] Here, (Ia)^2+(Qa)^2 is the sum of the square of the I data in the amplitude data DSA and the square of the Q data in the amplitude data DSA. (Ib)^2+(Qb)^2 is the sum of the square of the I data in the amplitude data DSB and the square of the Q data in the amplitude data DSB. (Ic)^2+(Qc)^2 is the sum of the square of the I data in the amplitude data DSC and the square of the Q data in the amplitude data DSC.

[0055] Then, the integrated data generating unit 33 selects the minimum value of the amplitude absolute values ​​ampA(d), ampB(d), and ampC(d) for each distance d. Hereinafter, the distance d when the minimum value of the amplitude absolute values ​​ampA(d), ampB(d), and ampC(d) is the amplitude absolute value ampA(d) is defined as distance da, the distance d when the minimum value of the amplitude absolute values ​​ampA(d), ampB(d), and ampC(d) is the amplitude absolute value ampB(d) is defined as distance db, and the distance d when the minimum value of the amplitude absolute values ​​ampA(d), ampB(d), and ampC(d) is the amplitude absolute value ampC(d) is defined as distance dc.

[0056] That is, the integrated data generating unit 33 determines the distance d to be one of the distances da, db, and dc based on the comparison result between the amplitude absolute values ​​ampA(d), ampB(d), and ampC(d).

[0057] Then, the integrated data generation unit 33 selects an amplitude corresponding to the distance da in the amplitude data DSA, an amplitude corresponding to the distance db in the amplitude data DSB, and an amplitude corresponding to the distance dc in the amplitude data DSC, and generates integrated data DI consisting of the selected amplitudes.

[0058] Figures 8 and 9 are diagrams showing an example of integrated data generated in a window function / FFT processing unit of a signal processing unit according to an embodiment of the present invention. Figure 9 is an enlarged view of region R2 in Figure 8. In Figures 8 and 9, the horizontal axis is distance d [m] and the vertical axis is amplitude [dB]. The solid line in Figures 8 and 9 indicates the amplitude of the integrated data DI. The dashed line in Figures 8 and 9 indicates the amplitude of the amplitude data DSA. The dashed line in Figures 8 and 9 indicates the amplitude of the amplitude data DSB. The two-dot chain line in Figures 8 and 9 indicates the amplitude of the amplitude data DSC.

[0059] 8 and 9, integrated data generator 33 generates integrated data DI which is a collection of the minimum values ​​of the amplitudes of amplitude data DSA, amplitude data DSB, and amplitude data DSC.

[0060] The integrated data generating unit 33 outputs the generated integrated data DI to the absolute value / logarithm conversion unit 40.

[0061] 10 and 11 are diagrams showing an example of integrated data generated in a window function / FFT processing unit of a signal processing unit according to an embodiment of the present invention. FIG. 10 is an enlarged view of a region R3 in FIG. 11. In FIG. 10 and FIG. 11, the horizontal axis is distance d [m], and the vertical axis is amplitude [dB]. The solid lines in FIG. 10 and FIG. 11 indicate the amplitude of the integrated data DI. The dashed lines in FIG. 10 and FIG. 11 indicate amplitude data DSA_1 generated by performing FFT processing or the like on an extracted beat signal EA based on a beat signal SD(n) containing interference and having its regions replaced with zero. The dashed lines in FIG. 10 and FIG. 11 indicate amplitude data DSA_2 generated by performing FFT processing or the like on an extracted beat signal EA based on an ideal beat signal SD(n) containing no interference and having no regions replaced with zero.

[0062] 10 and 11, the amplitude data DSA_1 generated based on the beat signal SD(n) from which the interference components have been removed has a larger range side lobe than the amplitude data DSA_2. Meanwhile, the integrated data DI has a peak shape similar to that of the amplitude data DSA_1 and DSA_2, and has a smaller range side lobe than the amplitude data DSA_1. Therefore, in the radar device 100 according to the embodiment of the present invention, it is possible to generate integrated data DI having a small range side lobe while maintaining a peak shape similar to that of an ideal beat signal not containing interference, based on the beat signal SD(n) from which the interference components have been removed, and therefore it is possible to more accurately detect targets based on the integrated data DI.

[0063] [Operation flow] The radar device according to the embodiment of the present invention includes a computer including a memory, and a processor such as a CPU in the computer reads out from the memory and executes a program including some or all of the steps of the following flowcharts and sequences. This program can be installed from an external source. This program is distributed in a state stored on a recording medium or via a communication line.

[0064] FIG. 12 is a flowchart defining an example of an operation procedure when the radar device according to the embodiment of the present invention generates integrated data.

[0065] 12, first, the radar device 300 generates extracted beat signals EA, EB, and EC by multiplying the beat signal SD(n) by window functions WfA, WfB, and WfC, respectively (step S102).

[0066] Next, the radar device 300 performs FFT processing or the like on the extracted beat signals EA, EB, EC to convert the extracted beat signals EA, EB, EC into amplitude data DSA, DSB, DSC (step S104).

[0067] Next, the radar device 300 calculates the amplitude absolute value ampA(d) for each distance d of the amplitude data DSA, the amplitude absolute value ampB(d) for each distance d of the amplitude data DSB, and the amplitude absolute value ampC(d) for each distance d of the amplitude data DSC (step S106).

[0068] Next, the radar device 300 selects the minimum value of the amplitude absolute values ​​ampA(d), ampB(d), and ampC(d) for each distance d, thereby dividing the distance d into one of distances da, db, and dc (step S108).

[0069] Next, the radar device 300 generates integrated data DI including the amplitude corresponding to the distance da in the amplitude data DSA, the amplitude corresponding to the distance db in the amplitude data DSB, and the amplitude corresponding to the distance dc in the amplitude data DSC (step S110).

[0070] In the signal processing unit 100 according to the embodiment of the present invention, the extracted signal generating unit 31 is configured to generate the extracted beat signals EA, EB, EC by multiplying the beat signal SD(n) by window functions WfA, WfB, WfC having different time domains as passbands, but this is not limited to the above. The extracted signal generating unit 31 may be configured to generate the extracted beat signals EA, EB, EC, which are beat signals SD(n) in a plurality of different time ranges by extracting a part or all of the beat signal SD(n) without using the window functions WfA, WfB, WfC.

[0071] In the signal processing unit 100 according to the embodiment of the present invention, the extracted signal generating unit 31 is configured to generate extracted beat signals EB, EC based on beat signals (n) in a plurality of time ranges that are consecutive in time, but the present invention is not limited to this. The extracted signal generating unit 31 may be configured to generate extracted beat signals EB, EC based on beat signals (n) in a plurality of time ranges that partially overlap. In other words, the passing time domains TPB, TPC may overlap in time. However, by configuring the extracted signal generating unit 31 to generate extracted beat signals EB, EC based on beat signals (n) in a plurality of time ranges that are consecutive in time, it is possible to prevent the same I signal Si(n) and Q signal Sq(n) whose amplitudes have been replaced with zero by the interference removing unit 20 from being included in both the extracted beat signals EB, EC.

[0072] In addition, in the signal processing unit 100 according to the embodiment of the present invention, the extracted signal generating unit 31 is configured to generate the extracted beat signal EA based on the beat signal SD(n) in the target time region Ta, but this is not limited to the above. The extracted signal generating unit 31 may be configured to generate the extracted beat signals EB and EC but not to generate the extracted beat signal EA. In other words, the extracted signal generating unit 31 may not include the window function processing unit 31A.

[0073] In addition, in the signal processing unit 100 according to the embodiment of the present invention, the extracted signal generating unit 31 is configured to generate the extracted beat signals EA, EB, and EC, but this is not limited thereto. The extracted signal generating unit 31 may be configured to generate two or four or more extracted beat signals E. For example, the extracted signal generating unit 31 may be configured to generate M extracted beat signals E based on beat signals SD(n) in M ​​different time ranges obtained by dividing the target time domain Ta into M. That is, the extracted signal generating unit 31 may be configured to include M window function processing units that generate beat signals E by multiplying the beat signal SD(n) by M window functions Wf having different passing time domains TP. Here, M is an integer equal to or greater than 2. The larger M is, the more integrated data DI with smaller range side lobes can be generated even if the beat signal SD(n) contains more interference waves. On the other hand, the smaller M is, the more simplified the configuration of the window function / FFT processing unit 30 can be.

[0074] In the signal processing unit 100 according to the embodiment of the present invention, the integrated data generating unit 33 is configured to generate the integrated data DI which is a set of minimum values ​​of the amplitudes of the amplitude data DSA, DSB, and DSC, but this is not limited to the above. The integrated data generating unit 33 may be configured to generate the integrated data DI by performing arithmetic processing such as calculating an average value on the amplitudes of the amplitude data DSA, DSB, and DSC.

[0075] Meanwhile, a technique capable of more accurately detecting a target based on a beat signal is desired.

[0076] For example, the radar system described in Patent Document 1 is configured to include a signal processing path that removes interference waves from beat signals and a signal processing path that does not remove interference waves from beat signals. In such a configuration, the range side lobes in the power spectrum generated based on the beat signals increase, and it may not be possible to accurately detect targets.

[0077] In contrast, in the signal processing unit 100 according to the embodiment of the present invention, the extracted signal generating unit 31 generates extracted beat signals EA, EB, EC extracted based on a plurality of different time ranges from a processed signal generated based on a beat signal between a transmitted signal and a received signal. The converting unit 32 converts the extracted beat signals EA, EB, EC into amplitude data DSA, DSB, DSC indicating the relationship between the distance d and the amplitude. The integrated data generating unit 33 generates integrated data DI by integrating the amplitude data DSA, DSB, DSC.

[0078] In this manner, extracted beat signals EA, EB, EC extracted based on a plurality of different time ranges are generated from a processed signal based on a beat signal, the extracted beat signals EA, EB, EC are converted into amplitude data DSA, DSB, DSC, respectively, and integrated data DI is generated by integrating the plurality of amplitude data DSA, DSB, DSC. This configuration makes it possible to generate the integrated data DI using amplitude data DSC based on the extracted beat signal EC that does not include beat signals SD(n) whose amplitudes have been replaced with zero to remove interference components, for example. This makes it possible to suppress an increase in range side lobes in the integrated data DI caused by replacing a portion of the amplitude of the beat signal SD(n) with zero, and to more accurately detect targets based on the integrated data DI with small range side lobes. Therefore, targets can be more accurately detected based on the beat signal SD(n).

[0079] Furthermore, in the signal processing unit 100 according to the embodiment of the present invention, the extracted signal generating unit 31 generates extracted beat signals EA, EB, and EC by multiplying the processed signal by a plurality of window functions having different pass time domains.

[0080] With this configuration, for example, by performing a Fourier transform on the extracted beat signals EA, EB, EC generated using an appropriate window function, it is possible to generate amplitude data DSA, DSB, DSC with smaller errors.

[0081] Furthermore, in the signal processing unit 100 according to the embodiment of the present invention, the integrated data generating unit 33 generates the integrated data DI by selecting one amplitude from among the amplitude data DSA, DSB, and DSC for each distance d.

[0082] With this configuration, for example, the amplitude data DS with the smallest range side lobes can be selectively used to easily generate integrated data DI with smaller range side lobes.

[0083] Moreover, in the signal processing unit 100 according to the embodiment of the present invention, the extracted signal generating unit 31 generates the extracted beat signals EB, EC extracted based on a temporally continuous time range.

[0084] With such a configuration, it is possible to prevent one beat signal SD(n), the amplitude of which has been replaced with zero in order to remove interference components, from being included in both of the extracted beat signals EB, EC, and therefore it is possible to prevent an increase in range side lobes in at least one of the amplitude data DSB, DSC based on the extracted beat signals EB, EC, caused by the amplitude of the beat signal SD(n) being replaced with zero.

[0085] Furthermore, in the signal processing section 100 according to the embodiment of the present invention, the extracted signal generating section 31 generates, as one of the extracted beat signals E, an extracted beat signal EA extracted based on a time range that includes a plurality of time ranges.

[0086] With this configuration, amplitude data DSA with higher distance resolution can be generated based on extracted data EA that is based on beat signals SD(n) with a larger number of samples, so that integrated data DI with higher distance resolution can be generated using the amplitude data DSA.

[0087] Moreover, in the signal processing unit 100 according to the embodiment of the present invention, the window functions include those having the same design shape.

[0088] With this configuration, it is no longer necessary to perform processing such as correction of the extracted beat signal in accordance with differences in the shapes of the window functions, and the integrated data DI can be generated with a simple configuration and processing.

[0089] Moreover, the radar device 300 according to the embodiment of the present invention includes a signal processing unit 100, a transmitting unit 120, and a receiving unit 150. The transmitting unit 120 transmits a transmission signal. The receiving unit 150 receives a reflected signal, which is a signal that is the transmitted transmission signal reflected by a target.

[0090] With this configuration, it is possible to realize a radar device 300 that can more accurately detect a target based on the beat signal SD(n).

[0091] In the radar device 300 according to the embodiment of the present invention, the transmitter 120 transmits a transmission signal via the rotating transmission antenna 130. The receiver 150 receives a reflected signal via the rotating reception antenna 140.

[0092] With this configuration, it is possible to transmit signals in various directions and receive reflected signals, making it possible to detect targets over a wider range.

[0093] Moreover, a radar signal processing method according to an embodiment of the present invention is a radar signal processing method in a signal processing unit 100 used in a radar device 300. In this radar signal processing method, first, the signal processing unit 100 The signal processor 100 generates extracted beat signals EA, EB, and EC based on different time ranges from a processed signal generated based on a beat signal between a transmitted signal and a received signal. The signal processor 100 then converts the extracted beat signals EA, EB, and EC into amplitude data indicating the relationship between the distance d and the amplitude. The signal processor 100 then generates integrated data DI by integrating the amplitude data DSA, DSB, and DSC.

[0094] In this way, the method of generating extracted beat signals EA, EB, EC extracted based on a plurality of different time ranges from a processed signal based on a beat signal, converting the extracted beat signals EA, EB, EC into amplitude data DSA, DSB, DSC, respectively, and generating integrated data DI by integrating the plurality of amplitude data DSA, DSB, DSC makes it possible to generate the integrated data DI using amplitude data DSC based on the extracted beat signal EC that does not include beat signals SD(n) whose amplitudes have been replaced with zero to remove interference components, for example, thereby suppressing an increase in range side lobes in the integrated data DI caused by replacing a portion of the amplitude of the beat signal SD(n) with zero, and making it possible to more accurately detect targets based on the integrated data DI with small range side lobes. Therefore, it is possible to more accurately detect targets based on the beat signal SD(n).

[0095] The above-described embodiments should be considered as illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0096] 20 Interference removal section 30 Window function / FFT processing section 31 Extraction signal processing section 31A, 31B, 31C Window function processing section 32 Conversion section 32A,32B,32C FFT processing section 33 Integrated Data Generation Department 40 Absolute value / logarithm conversion section 100 Signal processing section 110 Signal Generator 120 Transmitter 130 Transmitting Antenna 140 Receiving Antenna 150 Receiver 160 Mixer section 170 A / D conversion section 201 Radar Section 202 Display processing unit 300 Radar Equipment

Claims

1. an extracted signal generating unit that generates a plurality of extracted beat signals based on a plurality of different time ranges from a processed signal that is generated based on a beat signal between a transmission signal and a reception signal; a conversion unit that converts the extracted beat signals into amplitude data that indicates a relationship between distance and amplitude; an integrated data generating unit that generates integrated data by integrating a plurality of the amplitude data; The extracted signal generating unit generates the extracted beat signals from the processed signal by multiplying the processed signal by a plurality of window functions having different pass time domains.

2. The radar signal processing device according to claim 1 , wherein the integrated data generating unit generates the integrated data by selecting one of the amplitudes of the plurality of amplitude data for each distance.

3. 3. The radar signal processing device according to claim 1, wherein the extracted signal generating unit generates a plurality of the extracted beat signals extracted based on the time range that is continuous in time.

4. 4. The radar signal processing device according to claim 1, wherein the extracted signal generating unit generates, as one of the extracted beat signals, an extracted beat signal extracted based on a time range that includes a plurality of the time ranges.

5. The radar signal processing device according to claim 1 , wherein the plurality of window functions include those having the same shape design.

6. A radar signal processing device according to any one of claims 1 to 5, A transmitter for transmitting the transmission signal; a receiving unit that receives a reflected signal, which is a signal that is the transmitted signal reflected by a target.

7. The transmitter transmits the transmission signal via a rotating antenna, The radar device according to claim 6 , wherein the receiver receives the reflected signal via a rotating antenna.

8. A radar signal processing method in a radar signal processing device, comprising: generating a plurality of extracted beat signals based on a plurality of different time ranges from a processed signal generated based on a beat signal between a transmission signal and a reception signal; converting the plurality of extracted beat signals into amplitude data indicating a relationship between distance and amplitude; Generating integrated data by integrating a plurality of the amplitude data; a radar signal processing method for generating a plurality of extracted beat signals from the processed signal by multiplying the processed signal by a plurality of window functions having different passing time domains;

9. A radar signal processing program for use in a radar signal processing device, comprising: generating a plurality of extracted beat signals based on a plurality of different time ranges from a processed signal generated based on a beat signal between a transmission signal and a reception signal; converting the plurality of extracted beat signals into amplitude data indicating a relationship between distance and amplitude; and generating integrated data by integrating a plurality of the amplitude data. a radar signal processing program for generating a plurality of extracted beat signals from the processed signal by multiplying the processed signal by a plurality of window functions having different passing time domains;

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