JP5163017B2 - Chirp radar external interference wave removing method and apparatus - Google Patents

Description

  The present invention relates to a chirp radar external interference wave removing method and apparatus.

  In the chirp radar, as shown in FIG. 8, the chirp signal generated by the chirp signal generation unit 50 of the transmitter is frequency-converted and amplified by the frequency conversion / amplification unit 51, and the antenna 54 is connected via the transmission / reception switching unit 52 and the circulator 53. A pulsed transmission wave is transmitted from. The reflected wave reflected by the target is received by the antenna 54, and the received wave is input to the frequency conversion / amplification unit 56 via the circulator 53 and the transmission / reception switching unit 55, and the frequency conversion is performed by the frequency conversion / amplification unit 56. Then, the signal is amplified by the sampling unit 57 and then sampled by the sampling unit 57, and the target is detected based on the radar reception data R.

  When an external interference wave is present in addition to the pulsed transmission wave transmitted from the transmitter, the external interference wave becomes a noise source, and the S / N (signal-to-noise ratio) deteriorates. In order to improve S / N, chirp radars such as SAR (Synthetic Aperture Radar) use a wide frequency bandwidth, perform Fourier transform of the received signal, and use external interference waves in the frequency domain. Only the frequency component of is removed.

  A method of removing interference waves in the synthetic aperture radar disclosed in Patent Document 1 will be described with reference to FIG. In FIG. 10, reference numeral 60 denotes an original data signal, and 61 denotes an interference wave superimposed on the signal 60.

First, before performing compression processing in the SAR reproduction processing, fast Fourier transform is performed on one line of data, frequency domain data is calculated, and a power spectrum of the frequency domain data is calculated. Next, the power spectrum distribution data is subjected to a one-dimensional filtering process for the purpose of smoothing to set the smoothed data 62 as a comparison level, and the difference between the smoothed data 62 and the power spectrum distribution data or Calculate the ratio. Next, processing for detecting a frequency having a strong line spectrum in the power spectrum distribution data is performed. Then, it is checked whether the calculated difference or ratio is equal to or greater than a certain value, and it is assumed that a line spectrum exists in a portion where the difference or ratio is larger than the certain value. Thereby, an interference wave is determined.
Japanese Patent Laid-Open No. 7-27858

  However, as shown in FIG. 10, since the frequency of the interference wave is determined by comparing the power spectrum with a one-dimensional filtered level, depending on the situation of the interference wave, if the comparison level of the determination is high, the interference If the wave cannot be completely removed (A in FIG. 10) and the comparison level is too low, it may be determined as an interference wave up to a frequency band that is not an external interference wave (B in FIG. 10).

  In particular, when the interference wave is not the line spectrum C but has a wide bandwidth D to some extent, it is dragged by the interference wave and the one-dimensional filtered level is increased, making it difficult to determine the interference wave.

  As described above, in Patent Document 1, it is difficult to specify the band of the external interference wave and the external interference wave cannot be removed, or conversely, the frequency band that is not the external interference wave is scraped and the resolution is deteriorated. there were.

  An object of the present invention is to provide a chirp radar extraneous interference wave removal method and apparatus that removes extraneous interference waves contained in chirp radar received data with high accuracy.

In order to achieve the above object, a chirp radar extraneous interference wave elimination method according to the present invention provides a chirp radar extraneous interference elimination method that removes extraneous interference waves superimposed on a reflected wave reflected by a target when transmitting a pulsed transmission wave. A method,
Generate a frequency mask for removing the extraneous interference wave based on the frequency domain data of the reflected wave and the frequency domain data of the transmission wave,
The external interference wave is removed by removing a value corresponding to the frequency of the frequency mask from the frequency domain data of the reflected wave.

In addition, a chirp radar extraneous interference wave canceling apparatus that implements the chirp radar extraneous interference wave elimination method according to the present invention is a chirp that removes extraneous interference waves superimposed on a reflected wave reflected by a target when transmitting a pulse-like transmission wave. A radar external interference wave canceller,
Mask generating means for generating a frequency mask for removing the extraneous interference wave based on the frequency domain data of the reflected wave and the frequency domain data of the transmission wave;
And removing means for removing the external interference wave by removing a value corresponding to the frequency of the frequency mask from the frequency domain data of the reflected wave.

  According to the present invention, it is possible to remove the external interference wave included in the received data of the radar with high accuracy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The chirp radar extraneous interference wave elimination device according to the embodiment of the present invention is intended for a chirp radar extraneous interference wave elimination device that removes extraneous interference waves superimposed on a reflected wave reflected by a target when a pulsed transmission wave is transmitted. As shown in FIGS. 1, 4, 5, and 6, the basic configuration includes a mask generation unit 3 and a removal unit 24.

  In the chirp radar, as shown in FIG. 8, the chirp signal generated by the chirp signal generation unit 50 of the transmitter is frequency-converted and amplified by the frequency conversion / amplification unit 51, and the antenna 54 is connected via the transmission / reception switching unit 52 and the circulator 53. A pulsed transmission wave is transmitted from. The reflected wave reflected by the target is received by the antenna 54, and the received wave is input to the frequency conversion / amplification unit 56 via the circulator 53 and the transmission / reception switching unit 55, and the frequency conversion is performed by the frequency conversion / amplification unit 56. Then, the signal is amplified by the sampling unit 57 and then sampled by the sampling unit 57, and the target is detected based on the radar reception data R.

  When the reflected wave reflected by the target propagates in the air, an external interference wave existing in the air may be superimposed on the reflected wave. Since the chirp radar detects the target by correlating the transmitted wave and the reflected wave, if an external interference wave is superimposed on the reflected wave, the signal-to-noise ratio (S / N) degradation and the correlation error are detected. Thus, a phenomenon such as the appearance of a false image occurs and it becomes impossible to detect the target accurately. Therefore, it is necessary to remove the external interference wave superimposed on the reflected wave.

  A case will be described in which a chirp radar extraneous interference wave removing method for removing extraneous interference waves superimposed on a reflected wave is performed using the chirp radar extraneous interference wave removing apparatus according to the embodiment of the present invention.

  When the frequency domain data of the reflected wave (the waveform is W2 in FIG. 2) and the acquisition data of the transmission waveform (the waveform is W4 in FIG. 2) are input to the mask generation unit 3, the mask generation unit 3 is powered.・ External interference wave is removed based on the averaged reflected wave frequency domain data (the waveform is W9 in FIGS. 2 and 3) and the transmission wave frequency domain data (the waveform is W7 in FIGS. 2 and 3). A frequency mask 23 (the waveform is W14 in FIGS. 2 and 3) is generated (steps S6 to S15 in FIG. 2).

  The frequency domain data of the reflected wave (the waveform is W2 in FIG. 2) and the data of the frequency mask 2 are input to the removing means 24. The removing unit 24 removes a value corresponding to the frequency of the frequency mask 23 (the waveform is W14 in FIG. 2 and FIG. 3) from the frequency domain data (the waveform is W2 in FIG. 2) of the reflected wave, thereby removing the external interference. The wave is removed from the reflected wave data (step S16 in FIG. 2).

  This will be specifically described with reference to FIGS. In FIG. 3, the horizontal axis represents frequency and the vertical axis represents signal level. The reflected wave reflected by the target is subjected to frequency conversion processing by the frequency conversion / amplification unit 56 shown in FIG. 9, and the signal is sampled to obtain the radar reception data R. The radar reception data (reflected wave) R is time domain data, which is the waveform W1 shown in FIG. 2, and is converted into frequency domain data. The waveform of this frequency domain data is W2 shown in FIG. When the power spectrum generation process and the averaging process are performed on the waveform W2 of the frequency domain data, the waveform W9 is obtained by superimposing the external interference waves N1 and N2 (N) on the reflected wave R as shown in FIG. The reflected wave R which is the original data shown in FIG. 3 has the characteristics of a transmission wave transmitted from the chirp radar.

  The mask generation means 3 uses the frequency domain data of the reflected wave (the waveform is W2 in FIG. 2) and the acquired data of the transmission waveform (the waveform is W4 in FIG. 2), respectively. Based on the data (the waveform is W9 in FIGS. 2 and 3) and the frequency domain data of the transmission wave (the waveform is W7 in FIGS. 2 and 3), the frequency mask 23 for removing the external interference wave shown in FIG. (The waveform is W14 in FIGS. 2 and 3).

  The removing means 24 compares the frequency mask 23 and the reflected wave R (the waveform is the waveform W2 in FIG. 2) (interference wave determination) to determine the frequency of the external interference wave (the determined interference wave frequencies N1, N2). ) Is removed, and the external interference wave is removed from the reflected wave R by removing the value corresponding to the frequency of the frequency mask 23 from the frequency domain data of the reflected wave. The waveform of the reflected wave 13 after removing the external interference wave is W15 in FIG.

  Comparing the waveform of the reflected wave 13 shown in FIG. 3 with the reflected wave R before removal processing, the external interference wave N1 having a line spectrum exceeding the level of the reflected wave R is removed by comparing the frequency mask 23 and the reflected wave R. I understand that Further, it can be seen that the external interference wave N2 in the band spectrum is also removed.

Therefore, according to the embodiment of the present invention, since the extraneous interference wave is removed based on the spectrum of the transmission wave, the extraneous interference wave (external interference wave N1 of the line spectrum in FIG. 3) that cannot be completely removed by the related technology. Not only can the external interference waves N1 and N2 be removed without unnecessarily deleting the frequency band of the reflected waves. That is, according to the embodiment of the present invention, the external interference wave included in the received data of the radar can be removed with high accuracy. This is because the signal component of the radar reception data R is a reflected wave based on the transmission wave, and its spectrum is substantially the same as the spectrum of the transmission wave within the signal band, but the external interference wave is unrelated to the transmission wave. This is because of focusing on
(Embodiment 1)

  Next, a case where the power spectrum of the transmission wave is generated based on the actually transmitted pulsed transmission wave will be described as a first embodiment.

  As shown in FIG. 1, the chirp radar extraneous interference wave removing apparatus according to Embodiment 1 of the present invention has a mask generating means 3 and a removing means 24. The mask generating means 3 is a power spectrum generating means. 31, averaging processing means 32, calculation means 33, and frequency setting means 34. The mask generating means 3 includes a Fourier transform means 41, a power spectrum generating means 42, and an averaging processing means 43.

  In addition, a Fourier transform unit 21 is provided upstream of the mask generation unit 3, and an inverse Fourier unit 25 is provided downstream of the removal unit 24.

  Further, the radar reception data (reflected wave) R is input to the Fourier transform means 21, and the transmission waveform acquisition data 12 is input to the mask generation means 3.

  Acquisition of the radar reception data R will be described. In the chirp radar, as shown in FIG. 8, the chirp signal generated by the chirp signal generation unit 50 of the transmitter is frequency-converted and amplified by the frequency conversion / amplification unit 51, and the antenna 54 is connected via the transmission / reception switching unit 52 and the circulator 53. A pulsed transmission wave is transmitted from. The reflected wave reflected by the target is received by the antenna 54, and the received wave is input to the frequency conversion / amplification unit 56 via the circulator 53 and the transmission / reception switching unit 55, and the frequency conversion is performed by the frequency conversion / amplification unit 56. Then, the signal is amplified by the sampling unit 57 and then sampled by the sampling unit 57 to obtain the radar reception data R.

  Acquisition of the transmission waveform acquisition data 12 will be described. The chirp radar operates in a transmission waveform acquisition mode as shown in FIG. In this transmission waveform acquisition mode, the frequency-converted / amplified chirp signal is input to the receiver via the transmission / reception switching units 52, 53, not the transmitter antenna 54, and the receiver performs frequency conversion / amplification. Is sampled. The sampled data is output as transmission waveform acquisition data 12. The transmission waveform acquisition data 12 is data indicating the characteristics of the transmission wave, and is used for calibration by means such as a reference signal for chirp compression processing. Note that the observation operation as a chirp radar and the transmission waveform acquisition mode are generally performed in different modes, but there are also cases where they are performed simultaneously by time division or the like. In either case, it is only necessary to obtain the transmission waveform acquisition data 12 in the first embodiment of the present invention.

  A case where a chirp radar extraneous interference wave removing method for removing extraneous interference waves superimposed on a reflected wave using the chirp radar extraneous interference wave removing apparatus according to Embodiment 1 of the present invention is implemented based on FIGS. 1 and 2. explain. In FIG. 2, the horizontal axis of the characteristic diagram showing the waveforms W2, W3, and W5 to W14 indicates the frequency, and the vertical axis indicates the signal level. The horizontal axis of the characteristic diagram showing the waveform W1 of the radar reception data R, the waveform W4 of the transmission waveform data 12, and the waveform W15 of the radar reception data after removing the interference wave indicates time, and the vertical axis indicates the signal level.

  When transmission waveform data (chirp replica; hereinafter referred to as a transmission wave) 12 acquired in the transmission waveform acquisition mode is input to the mask generation means 3 (step S5 in FIG. 2), the time domain of the transmission wave 12 is obtained by the Fourier transform means 41. Data is converted into frequency domain data (step S6 in FIG. 2). Since the transmission wave 12 acquired in the transmission waveform acquisition mode has no external interference wave superimposed thereon as shown by the waveform W4 in FIG. 2, the waveform W4 is not disturbed. As shown by a waveform W5 in FIG. 2, the Fourier-transformed transmission wave is converted from time-domain data to frequency-domain data and is decomposed into a continuous spectrum of the frequency component (F7 in FIG. 2).

Based on the frequency domain data of the transmission wave 12 subjected to Fourier transform, the power spectrum generation means 42 is represented by a waveform W6 by the sum of the square of the in-phase component I and the square of the quadrature component Q (I ² + Q ² ). A power spectrum is generated (step S8 in FIG. 2). Next, the averaging processing means 43 integrates (averages) the results of generating the power spectrum in the PRI direction, thereby reducing random noise on the power spectrum (waveform W6) (step S9 in FIG. 2). It can be seen that the waveform W7 of the power spectrum with reduced random noise is smoother than the waveform W6 of the power spectrum before averaging, that is, the random noise is reduced.

  The radar reception data R is data reproduced based on the reflected wave reflected by the target when the pulsed transmission wave is transmitted. When the radar reception data R is input (step S1 in FIG. 2), the Fourier transform means 21 Fourier-transforms the time domain data of the radar reception data R into frequency domain data (step S2 in FIG. 2). As shown in the waveform W1 of FIG. 2, the radar reception data (hereinafter referred to as a reflected wave) R has a disturbance in the waveform as compared with the waveform W5 because the external interference wave is superimposed. As shown by the waveform W2 in FIG. 2, the Fourier-transformed reflected wave R is converted from time-domain data to frequency-domain data and is decomposed into a continuous spectrum of the frequency component (F2 in FIG. 2). .

When the mask generation means 3 acquires the power spectrum of the transmission wave from the averaging processing means 43 and then receives the reflected wave R that has undergone Fourier transform from the Fourier means 21, the spectrum generation means 31 of the mask generation means 3 causes the radar reception data R to be received. On the basis of the frequency domain data, a power spectrum indicated by the waveform W8 is generated by the sum of the square of the in-phase component I and the square of the quadrature component Q (I ² + Q ² ) (step S10 in FIG. 2).

  Next, the averaging processing means 32 integrates (averages) the results of generating the power spectrum of the reflected wave R in the PRI direction, thereby reducing random noise on the power spectrum (waveform W8) of the reflected wave R. (Step S11 in FIG. 2). It can be seen that the waveform W9 of the power spectrum with reduced random noise is smoother than the waveform W8 of the power spectrum before averaging, that is, the random noise is reduced. However, it can be seen that the waveform W9 of the power spectrum of the reflected wave R is superimposed with the external interference wave N as compared with the waveform W7 of the power spectrum of the transmission wave 12.

  When the power spectrum of the reflected wave R (the waveform is W9 in FIG. 2) and the power spectrum of the transmission wave 12 (the waveform is W7 in FIG. 2) are input, the calculation means 33 transmits the frequency domain data of the reflected wave R and the transmission. Based on the frequency domain data of the wave 12, a frequency mask (its waveform is W14 in FIG. 2) for removing the external interference wave N is generated.

  Specifically, first, the calculating means 33 calculates a deviation value by obtaining a ratio of the power spectrum of the reflected wave R to the power spectrum of the transmission wave 12. That is, the calculation means 33 divides the power spectrum waveform averaged by the averaging processing means 43 for each frequency by the power spectrum waveform averaged by the averaging processing means 32 (step S12 in FIG. 2). The waveform resulting from the division is the waveform 10 in FIG. The division process at this time includes a measure for zero division. For example, when the denominator is 0, this procedure outputs the maximum value set internally.

  Next, the calculation means 33 performs chirp bandwidth limitation that sets a value other than the preset chirp bandwidth L to 0 as necessary (step S13 in FIG. 2). The waveform after the chirp band limitation is the waveform W11 in FIG.

  Next, the calculating means 33 obtains a deviation value at each frequency for the result after the chirp band limiting process (step S14 in FIG. 2). The deviation value H at each frequency is W12 shown in FIG. Further, the frequency setting unit 34 receives the result of the calculation unit 33, sets a frequency exceeding a preset threshold D as a mask frequency, and generates a frequency mask 23 (see FIG. 2). 2 step S15). The spectrum of the frequency mask 23 is W14 in FIG.

  The removing unit 24 removes a value corresponding to the frequency of the frequency mask 23 from the frequency domain data of the reflected wave R Fourier-transformed by the Fourier transform unit 21 (step S16 in FIG. 2). The waveform is W3 in FIG.

  The inverse Fourier transform unit 25 performs an inverse Fourier transform on the result of the removal process performed by the removal unit 24, and returns the data in the frequency domain to the data in the time domain, thereby obtaining the radar reception data 13 from which the external interference wave is removed. (Step S17 in FIG. 2). The waveform of the radar reception data 13 after removing the interference wave is W15 in FIG.

  This will be specifically described with reference to FIG. The mask generation means 3 generates a frequency mask (whose waveform is W14) in FIG. 3 in order to remove the external interference wave based on the frequency domain data of the reflected wave and the frequency data of the transmission wave (FIG. 2). Step S15).

  The removing unit 24 compares the frequency mask 23 and the reflected wave R (determination of interference wave) to determine the frequency of the external interference wave (determined interference wave frequencies N1 and N2), and the frequency region of the reflected wave By removing the value corresponding to the frequency of the frequency mask 23 from the data, the external interference wave is removed from the reflected wave data R (step S16 in FIG. 2). The waveform of the reflected wave 13 after removing the external interference wave is W15 in FIG.

  Comparing the waveform of the reflected wave 13 shown in FIG. 3 with the reflected wave R before removal processing, the external interference wave N1 having a line spectrum exceeding the level of the reflected wave R is removed by comparing the frequency mask 23 and the reflected wave R. I understand that Further, it can be seen that the external interference wave N2 in the band spectrum is also removed.

  Therefore, according to Embodiment 1 of the present invention, since the external interference wave is removed based on the spectrum of the transmission wave, the external interference wave that cannot be completely removed by the related technology (external interference wave N1 of the line spectrum in FIG. 3). In addition, the external interference waves N1 and N2 can be removed without unnecessarily deleting the frequency band of the reflected wave. That is, according to the first embodiment of the present invention, it is possible to remove the external interference wave included in the received data of the radar with high accuracy.

  Furthermore, according to the first embodiment of the present invention, after the random noise on the power spectrum is reduced, the deviation value is calculated by obtaining the ratio of the power spectrum of the reflected wave to the power spectrum of the transmission wave. As a result, the external interference wave included in the received data of the radar can be removed with high accuracy.

Furthermore, according to the first embodiment of the present invention, since the removal is performed based on the spectrum of the transmission waveform acquisition data, it is possible to improve the removal accuracy even for interference waves having a somewhat wide bandwidth.
(Embodiment 2)

  In the first embodiment of the present invention, the case where the power spectrum of the transmission wave is generated based on the actually transmitted pulsed transmission wave has been described, but the present invention is not limited to this.

In Embodiment 2 of the present invention, instead of the configuration in which the mask frequency for interference wave removal is determined based on the power spectrum generated based on the transmission waveform acquisition data, the power spectrum of the transmission wave is changed as shown in FIG. It may be generated based on the modeled transmission wave and directly input as the reference spectrum 14. The reference spectrum 14 may be used after partially correcting or changing the power spectrum generated based on the transmission waveform acquisition data, or a theoretically conceivable power spectrum may be used. The reference spectrum 14 may use the spectrum of the transmission waveform confirmed in the ground test. The spectrum of the modeled transmission wave is the waveform W7 in FIG.
(Embodiment 3)

  It is also possible to implement the interference wave removal method according to the embodiment of the present invention during the chirp compression process. This example will be described as a third embodiment.

  In the chirp compression process, the radar reception data (reflected wave) R is usually subjected to Fourier transform by the Fourier transform means 21, and the correlation with the frequency domain signal 15 of the reference signal is correlated in the frequency domain of the reflected wave R subjected to the Fourier transform. The chirp compression is performed by taking the processing means 26 and performing the inverse Fourier transform by the inverse Fourier transform means 25 (16).

  In the third embodiment of the present invention, as shown in FIG. 5, the reflected wave using the frequency mask 23 generated by the mask generation processing unit 3 is applied to the Fourier transform result of the radar reception data (reflected wave) R by the Fourier transform unit 21. The external interference wave of R is removed, the result is correlated with the frequency domain signal of the reference signal, and inverse Fourier transform is performed to perform chirp compression. The configuration and method for removing the external interference wave superimposed on the reflected wave R are the same as those shown in FIGS.

According to the third embodiment of the present invention, it is possible to remove the external interference wave included in the received data of the radar with high accuracy, thereby accurately performing the correlation process with the frequency domain signal of the reference signal. .
(Embodiment 4)

  The transmission waveform acquisition data 12 is often used as a reference signal for chirp compression, and the configuration in that case is shown in FIG.

In Embodiment 4 of the present invention, as shown in FIG. 6, the Fourier transform means 41 of the mask generation means 3 performs the Fourier transform of the transmission waveform acquisition data 12 as the frequency domain signal 15 of the reference signal, and the correlation process. Used for chirp compression. The transmission wave system acquisition data 12 subjected to Fourier transform may be integrated (averaged) in the PRI direction, and the result may be used as the frequency domain signal 15 of the reference signal in FIG. 6 for correlation processing.
(Embodiment 5)

  In the first embodiment shown in FIG. 1, the transmission waveform data 12 is Fourier-transformed by the Fourier transform means 41 of the mask generating means 3 and the power spectrum is generated by the power spectrum generating means 42. However, the present invention is not limited to this (FIG. 1). 7 right).

  Before the Fourier transform is performed on the transmission waveform data 12, the averaging processing means 43 integrates (averages) in the PRI direction, and the processing of the Fourier transform means 41 and the power spectrum generation means 42 is executed on the result. It is good (left side of FIG. 7).

  According to the fifth embodiment of the present invention, noise in the transmission waveform data 12 can be removed before the processing of the Fourier transform unit 41 and the power spectrum generation unit 42 is executed.

  According to the present invention, it is easy to specify the band of the external interference wave, the external interference wave can be removed with high accuracy, and the frequency band that is not the external interference wave is not cut, and the resolution is improved. it can.

It is a block diagram which shows the chirp radar extraneous interference wave removal apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the chirp radar external interference wave removal apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the process of removing an external interference wave. It is a block diagram which shows the chirp radar extraneous interference wave removal apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the structure which implements the interference wave removal method regarding embodiment of this invention in a chirp compression process. It is a block diagram which shows the example of a change of embodiment shown in FIG. It is a block diagram which shows the example of a change of embodiment shown in FIG. It is a block diagram which shows a chirp radar. It is a block diagram which shows the transmission waveform acquisition mode operation state in a chirp radar. It is a flowchart which shows the related extraneous interference wave removal method.

Explanation of symbols

3 Mask generation means 23 Frequency mask 24 Removal means 31 Power spectrum generation means 32 Averaging processing means 33 Calculation means 34 Frequency setting means

Claims (10)

A chirp radar external interference wave removing method for removing an external interference wave superimposed on a reflected wave reflected by a target when transmitting a pulsed transmission wave,
Generate a power spectrum based on the frequency domain data of the reflected wave, generate a power spectrum based on the frequency domain data of the transmission wave,
Reduce random noise on the power spectrum of both,
Calculate the deviation value by calculating the ratio of the power spectrum of the reflected wave to the power spectrum of the transmission wave,
By setting a frequency at which the deviation value exceeds a threshold value as a mask frequency, a frequency mask for removing the external interference wave is generated,
A chirp radar extraneous interference wave removing method, wherein the extraneous interference wave is eliminated by removing a value corresponding to the frequency of the frequency mask from the frequency domain data of the reflected wave. Average the power spectrum of the reflected wave and the power spectrum of the transmission wave,
The chirp radar extraneous interference wave elimination method according to claim 1 , wherein the deviation value at each frequency is calculated by performing division processing for each frequency based on the averaged power spectrum. By limiting the chirp bandwidth, chirp radar foreign interference wave removal process according to claim 1 for calculating a deviation value seeking the ratio of the power spectrum of the reflected wave with respect to the power spectrum of the transmission wave. The chirp radar extraneous interference wave elimination method according to claim 1 , wherein a power spectrum of the transmission wave is generated based on a transmission wave actually transmitted. The chirp radar extraneous interference wave elimination method according to claim 1 , wherein the power spectrum of the transmission wave is generated based on the modeled transmission wave. A chirp radar external interference wave removing device that removes an external interference wave superimposed on a reflected wave reflected by a target when transmitting a pulsed transmission wave,
A mask generation means for generating a power spectrum based on the frequency domain data of the reflected wave, and generating a power spectrum based on the frequency domain data of the transmission wave;
Averaging processing means for reducing random noise on the power spectrum of both,
Calculating means for calculating a deviation value by calculating a ratio of the power spectrum of the reflected wave to the power spectrum of the transmission wave;
A frequency mask for removing the extraneous interference wave is generated by setting a frequency at which the deviation value exceeds a threshold as a mask frequency, and corresponds to the frequency of the frequency mask from the frequency domain data of the reflected wave A chirp radar extraneous interference wave removing apparatus, comprising: an interference wave removing means for removing the extraneous interference wave by removing the value. The chirp radar extraneous interference wave removing apparatus according to claim 6 , wherein the calculating means calculates the deviation value at each frequency by performing a division process for each frequency based on the averaged power spectrum. 7. The chirp radar extraneous interference wave canceling apparatus according to claim 6 , wherein the calculating means calculates a deviation value by limiting a chirp bandwidth and obtaining a ratio of a power spectrum of the reflected wave to a power spectrum of the transmission wave. The chirp radar extraneous interference wave canceling apparatus according to claim 6 , wherein the mask generating means uses a power spectrum of a transmission wave generated based on a transmission wave actually transmitted. The chirp radar extraneous interference wave canceling apparatus according to claim 6 , wherein the mask generation unit uses a modeled power spectrum of a transmission wave.

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