JP2002116251A - Radar signal processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radar signal processing device for removing blurring and bleeding of images by reducing errors in calculating the amount of phase correction due to the drift of a detected reference point frequency. SOLUTION: After observation time is expanded by inserting zero data in the time direction of a reception signal by a zero insertion circuit 22, frequency is analyzed by a division-frequency analysis circuit 9. A high-frequency component is removed from a waveform, having frequency and amplitude obtained by the division frequency analysis circuit 9 by a low-pass filter 23, and data are cut for a region, where each amplitude value exceeds a threshold, that has been set by a threshold-setting circuit 15 by a data-cutting circuit 14. A maximum point frequency detection circuit 16 detects all maximum points to a waveform which have the cut frequency and amplitude, and frequency at that point is calculated. An average frequency detection circuit 17 detects the average value of frequency at all maximum points being detected by a maximum point frequency detection circuit 16 as the reference point frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to correction of a phase shift of a target reception signal in, for example, a radar signal processing device of a high-resolution radar device.

[0002]

2. Description of the Related Art FIG. 13 is a block diagram of a radar signal processing device of a high-resolution radar device. In the drawing, reference numeral 1 denotes a data interface unit for converting a target reception signal input from the radar device into a data format that can be processed internally. Reference numeral 2 denotes a pulse compression unit for pulse-compressing the target reception signal converted by the data interface unit 1. Reference numeral 3 denotes a distance correction unit for correcting a time-dependent distance shift of the target reception signal pulse-compressed by the pulse compression unit 2. A phase correction unit for correcting a phase shift due to time of the target reception signal corrected by the distance correction unit 3; a frequency analysis unit 5 for separating the Doppler frequency of the target reception signal corrected by the phase correction unit 4; A detector for converting the frequency spectrum of the target reception signal, which has been frequency-analyzed by the unit 5, into image data; and 7, an interface between the image data obtained by the detector 6 and the display. A display interface unit for adjusting display data and generating display image data; SM, a target reception signal input from the radar device; RS, a target reception signal whose distance deviation due to time has been corrected by the distance correction unit 3; An initial distance from the target center of gravity, RD is a target reception signal whose phase shift due to time has been corrected by the phase correction unit 4, and D is display image data.

FIG. 14 is a configuration diagram of a conventional phase correction unit 4 in the radar signal processing apparatus of FIG.
RG, RD and 4 are the same as those in FIG. 13, and 8 is an initial distance RG between the radar and the target center of gravity, which is the target reception signal RS and the distance deviation due to time output from the distance correction unit 3 and has been corrected.
9 is a divided frequency analysis circuit that analyzes the frequency of a target received signal at an initial distance RG between the radar output from the buffer circuit 8 and the target center of gravity in a small section in the time direction, and 10 is a divided frequency analysis circuit 9 A maximum amplitude value detection circuit for detecting, as a reference point frequency, a frequency having the maximum amplitude value with respect to the waveform of the frequency and amplitude obtained in the step 11;
Is a smoothing circuit for smoothing the trajectory of the reference point frequency detected by the maximum amplitude value detection circuit 10 in the time direction, and 12 is a phase correction amount based on the trajectory of the reference point frequency smoothed by the smoothing circuit 11 in the time direction. Is a phase correction circuit for calculating the phase of the target reception signal output from the buffer circuit 8 using the phase correction amount calculated by the phase correction amount calculation circuit 12, and GS is a radar. This is a target reception signal at an initial distance RG from the target center of gravity.

Next, the operation will be described. The target reception signal SM input from the radar device is converted into a data format that can be processed internally by the data interface unit 1, pulse-compressed by the pulse compression unit 2, and corrected by the distance correction unit 3 for a distance shift due to time. The signal is output to the phase correction unit 4 as the target reception signal RS. Further, the distance correction unit 3 calculates an initial distance RG between the radar and the target center of gravity, and outputs the calculated initial distance RG to the phase correction unit 4. The phase correction unit 4 corrects the time-dependent phase shift of the target reception signal RS using the target reception signal RS whose distance shift due to time has been corrected and the initial distance RG between the radar and the target center of gravity, and performs frequency analysis as the target reception signal RD. Output to section 5.

[0005] The target reception signal RD is subjected to frequency analysis by the frequency analysis unit 5 to be converted into a frequency spectrum, and is converted into image data by the detection unit 6, and then interfaced with the display by the display interface unit 7. It is adjusted and output as display image data D.

Next, the operation of the phase correction section 4 will be described. The target reception signal RS and the initial distance RG between the radar and the target center of gravity, the distance of which has been corrected by the time input from the distance correction unit 3, are stored in the buffer circuit 8, and the initial reception signal RS and the initial distance between the radar and the target center of gravity are stored. It is output as the target reception signal GS at the distance RG.

The target reception signal GS at the initial distance RG between the radar and the target center of gravity is subjected to frequency analysis in a small section in the time direction by the divided frequency analysis circuit 9, and the maximum amplitude value is detected for the obtained frequency and amplitude waveforms. After the frequency at which the amplitude value becomes maximum is detected as the reference point frequency by the circuit 10, it is output to the smoothing circuit 11. The smoothing circuit 11 smoothes the locus of the reference point frequency in the time direction, and the phase correction amount calculating circuit 12 calculates the phase correction amount from the smoothed locus.

[0008] The phase correction circuit 13 is a phase correction amount calculation circuit 1
Using the phase correction amount calculated in step 2, the phase of the target received signal RS output from the buffer circuit 8 and corrected for the distance shift due to time is corrected, and the frequency analysis is performed as the target received signal RD corrected for the phase shift due to time. Output to the unit 5.

Further, the phase correction section 4 will be described with reference to FIG. FIG. 15 is a diagram illustrating a processing method of the phase correction unit 4. Target received signal RS in which distance deviation due to time has been corrected
(Where, i is the range bin number, j is the pulse hit numbers, i, j is a natural number.) The S _{i, j,} when the range bin numbers that exist in the initial distance RG between the radar and the target center of gravity is defined as r radar The target reception signal GS at the initial distance RG between the target and the target center of gravity is represented as _{Sr, j,} and a waveform as shown in FIG. When frequency analysis of S _{r, j} is performed in a small section in the time direction (pulse hit direction) by the divided frequency analysis circuit 9, a waveform as shown in FIG. 15B is obtained, and the frequency f _m and the amplitude A _m ^k are obtained. (Where k is the division frequency analysis number, m
Is a frequency bin number, and k and m are natural numbers. ) Is represented by “Equation 1”.

[0010]

(Equation 1)

[0011] In the amplitude maximum detection circuit 10 for each division frequency analysis number k, and detects the frequency when the amplitude A _m ^k takes a maximum value, when it as a reference point frequency f ^k, the time t _k and the reference The relationship between the point frequencies f ^k is as shown in the plot of FIG. In the smoothing circuit 11, the plot of FIG.
When smoothing the waveform shown by the solid line shown in FIG. 15 (c) is obtained, the relationship between the time t _k and the frequency f ^'k is expressed by "Equation 2".

[0012]

(Equation 2)

In the phase correction amount calculating circuit 12, the phase correction amount is calculated.
W _j is calculated by “Equation 3”.

[0014]

(Equation 3)

The phase correction circuit 13 corrects the phase of S _{i, j} by “Equation 4” using the phase correction amount W _j . However, the target received signal RD in which the phase shift due to time has been corrected is defined as S ′ _{i, j} .

[0016]

(Equation 4)

[0017]

In the conventional radar signal processing apparatus as described above, the frequency and amplitude waveforms after the divided frequency analysis have multiple peaks, and the position of the peak having the maximum amplitude value is determined every time. In the case of a large fluctuation, the detected reference point frequency fluctuates, so that an accurate phase correction amount cannot be calculated, and there is a problem that an image is blurred or blurred.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and it has been found that the detected reference frequency fluctuates, so that an accurate phase correction amount cannot be calculated and an image is blurred or blurred. It is an object of the present invention to obtain a radar signal processing device for preventing such a problem.

[0019]

According to a first aspect of the present invention, there is provided a radar signal processing apparatus comprising: a phase correction means for storing a target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity; A divided frequency analysis means for frequency-analyzing a target reception signal at an initial distance between the radar and the target center of gravity output from the storage means in a small section in the time direction, a reception signal to be subjected to frequency analysis by the division frequency analysis means Time extension means for extending the observation time in the time direction, high-frequency component removal means for removing high-frequency components from the frequency and amplitude waveforms obtained by the divided frequency analysis means, and frequency and amplitude output from the high-frequency component removal means Data extracting means for extracting data based on a threshold value for the waveform of the waveform, and setting the maximum of the extracted frequency and amplitude waveforms. A maximum point frequency detection means for detecting a point at which the maximum point frequency is detected, and an average frequency detection means using a mean value of the frequencies detected by the maximum point frequency detection means as a reference point frequency. Things.

A radar signal processing device according to a second aspect of the present invention comprises:
In the first invention, the phase correction means includes a smoothing means for smoothing a trajectory of the reference point frequency detected by the average frequency detection means in a time direction, a time of the reference point frequency smoothed by the smoothing means. Phase correction amount calculation means for calculating a phase correction amount from a trajectory in a direction, and a phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means Is provided.

A radar signal processing apparatus according to a third aspect of the present invention comprises:
In the first invention, the phase correction means includes a buffer circuit for storing the target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity, and a buffer between the radar output from the buffer circuit and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target received signal at an initial distance in a small section in the time direction, and inserting 0 data in the time direction of a target received signal when frequency analysis is performed by the above-described divided frequency analysis circuit, and observing time. A low-pass filter that removes high-frequency components from the frequency and amplitude waveforms obtained by the above-described divided frequency analysis circuit, and a frequency and amplitude waveform from which high-frequency components are removed by the low-pass filter. A data extraction circuit for extracting data, and a threshold necessary for extracting data with the data extraction circuit. A value setting circuit, a maximum point frequency detection circuit that detects a maximum point in the frequency and amplitude waveforms cut out by the data extraction circuit and calculates the frequency at that time, and an average of the frequencies detected by the maximum point frequency detection circuit. An average frequency detection circuit having a value as a reference point frequency, a smoothing circuit for smoothing a locus in the time direction of the reference point frequency detected by the average frequency detection circuit, and a reference point frequency smoothed by the smoothing circuit. A phase correction amount calculation circuit for calculating a phase correction amount from a trajectory in the time direction, and a phase correction for correcting the phase of the target reception signal output from the buffer circuit using the phase correction amount calculated by the phase correction amount calculation circuit And a circuit.

A radar signal processing device according to a fourth aspect of the present invention comprises:
The phase correction means stores the target reception signal corrected by the distance correction means and the initial distance between the radar and the target center of gravity, and the target reception signal at the initial distance between the radar and the target center of gravity output from the storage means. A divided frequency analyzing means for performing frequency analysis in a small section in the time direction, a time extending means for extending an observation time in a time direction of a target signal to be subjected to frequency analysis by the divided frequency analyzing means, and a divided frequency analyzing means. High-frequency component removing means for removing high-frequency components for the waveform of the frequency and amplitude, data extracting means for extracting data based on the threshold value of the frequency and amplitude waveforms output from the high-frequency component removing means, the cut-off frequency and Maximum point frequency detection that detects the maximum point in the amplitude waveform and calculates the frequency of the maximum point Stage, which is constituted by a center frequency detecting unit for the reference-point frequency center value of the frequency detected by the maximum point frequency detecting means.

A radar signal processing device according to a fifth aspect of the present invention
In the fourth aspect, the phase correction means includes a smoothing means for smoothing a trajectory of the reference point frequency detected by the center frequency detection means in a time direction, a time of the reference point frequency smoothed by the smoothing means. Phase correction amount calculation means for calculating a phase correction amount from a trajectory in a direction, and a phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means Is provided.

According to a sixth aspect of the present invention, there is provided a radar signal processing apparatus comprising:
In a fourth aspect, the phase correction means includes a buffer circuit for storing the target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity, and a buffer circuit for storing the radar output from the buffer circuit and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target received signal at an initial distance in a small section in the time direction, and inserting 0 data in the time direction of a target received signal when frequency analysis is performed by the above-described divided frequency analysis circuit, and observing time. A low-pass filter that removes high-frequency components from the frequency and amplitude waveforms obtained by the above-described divided frequency analysis circuit, and a frequency and amplitude waveform from which high-frequency components are removed by the low-pass filter. A data extraction circuit for extracting data, and a threshold necessary for extracting data with the data extraction circuit. A value setting circuit, a maximum point frequency detection circuit that detects a maximum point of the frequency and amplitude waveforms cut out by the data extraction circuit and calculates the frequency at that time, and a center of the frequency detected by the maximum point frequency detection circuit. A center frequency detection circuit having a value as a reference point frequency, a smoothing circuit for smoothing a locus in the time direction of the reference point frequency detected by the center frequency detection circuit, and a reference point frequency smoothed by the smoothing circuit. A phase correction amount calculation circuit for calculating a phase correction amount from a trajectory in the time direction, and a phase correction for correcting the phase of the target reception signal output from the buffer circuit using the phase correction amount calculated by the phase correction amount calculation circuit And a circuit.

According to a seventh aspect of the present invention, there is provided a radar signal processing apparatus comprising:
The phase correction means stores the target reception signal corrected by the distance correction means and the initial distance between the radar and the target center of gravity, and the target reception signal at the initial distance between the radar and the target center of gravity output from the storage means. A divided frequency analyzing means for performing frequency analysis in a small section in the time direction, a time extending means for extending an observation time in a time direction of a target signal to be subjected to frequency analysis by the divided frequency analyzing means, and a divided frequency analyzing means. High-frequency component removing means for removing high-frequency components for the waveform of the frequency and amplitude, data extracting means for extracting data based on the threshold value of the frequency and amplitude waveforms output from the high-frequency component removing means, the cut-off frequency and Maximum point frequency detection that detects the maximum point in the amplitude waveform and calculates the frequency of the maximum point Stage, which is constituted by the minimum frequency detecting means as a reference point frequency the minimum frequency detected by the maximum point frequency detecting means.

According to an eighth aspect of the present invention, there is provided a radar signal processing apparatus comprising:
In the seventh invention, the phase correction means includes a smoothing means for smoothing a trajectory of the reference point frequency detected by the minimum frequency detection means in a time direction, a time of the reference point frequency smoothed by the smoothing means. Phase correction amount calculation means for calculating a phase correction amount from a trajectory in a direction, and a phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means Is provided.

The radar signal processing apparatus according to the ninth aspect is
In the seventh invention, the phase correction means includes a buffer circuit for storing the target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity, and a buffer circuit for storing the radar output from the buffer circuit and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target received signal at an initial distance in a small section in the time direction, and inserting 0 data in the time direction of a target received signal when frequency analysis is performed by the above-described divided frequency analysis circuit, and observing time. A low-pass filter that removes high-frequency components from the frequency and amplitude waveforms obtained by the above-described divided frequency analysis circuit, and a frequency and amplitude waveform from which high-frequency components are removed by the low-pass filter. A data extraction circuit for extracting data, and a threshold necessary for extracting data with the data extraction circuit. A value setting circuit, a maximum point frequency detection circuit that detects a maximum point in the frequency and amplitude waveforms cut out by the data extraction circuit and calculates the frequency at that time, and a minimum frequency detected by the maximum point frequency detection circuit. A minimum frequency detection circuit having a value as a reference point frequency, a smoothing circuit for smoothing a trajectory in the time direction of the reference point frequency detected by the minimum frequency detection circuit, and a reference point frequency smoothed by the smoothing circuit. A phase correction amount calculation circuit for calculating a phase correction amount from a trajectory in the time direction, and a phase correction for correcting the phase of the target reception signal output from the buffer circuit using the phase correction amount calculated by the phase correction amount calculation circuit And a circuit.

In a radar signal processing apparatus according to a tenth aspect of the present invention, the phase correction means stores the target reception signal corrected by the distance correction means and the initial distance between the radar and the target center of gravity, and is output from the storage means. A divided frequency analysis means for frequency-analyzing a target reception signal in a small section in the time direction at an initial distance between the radar and the target center of gravity, and an observation time in a time direction of the reception signal to be subjected to frequency analysis by the above-mentioned division frequency analysis means. Time expansion means for expanding the high frequency component removal means for removing high frequency components for the frequency and amplitude waveforms obtained by the above-mentioned division frequency analysis means,
A data cutout unit that cuts out the data of the frequency and amplitude waveforms output from the high frequency component removing unit based on a threshold value, and detects a point at which the cutoff frequency and amplitude waveform has a maximum, and detects the maximum point. The maximum point frequency detecting means for calculating the frequency, and the maximum frequency detecting means using the maximum value of the frequency detected by the maximum point frequency detecting means as a reference point frequency.

The radar signal processing apparatus according to an eleventh aspect of the present invention is the radar signal processing apparatus according to the tenth aspect, wherein the phase correction means includes a smoothing means for smoothing a trajectory in the time direction of the reference point frequency detected by the maximum frequency detection means. Phase correction amount calculating means for calculating a phase correction amount from a locus in the time direction of the reference point frequency smoothed by the smoothing means,
A phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means.

In a radar signal processing apparatus according to a twelfth aspect, in the tenth aspect, the phase correction means includes a buffer circuit for storing the target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target reception signal at an initial distance between the radar output from the buffer circuit and the target center of gravity in a small section in the time direction, and a reception target when the frequency analysis is performed by the divided frequency analysis circuit A zeroing circuit for extending the observation time by inserting data of zero in the time direction of the signal, a low-pass filter for removing high-frequency components from the frequency and amplitude waveforms obtained by the above-mentioned divisional frequency analysis circuit,
A data cutout circuit for cutting out data on the waveform of the frequency and amplitude from which the high-frequency component has been removed by the low-pass filter, a threshold setting circuit for setting a threshold necessary for cutting out data with the data cutout circuit, A maximum point frequency detection circuit that detects a maximum point in the cut-out frequency and amplitude waveforms and calculates the frequency at that time, and a maximum frequency that uses the maximum value of the frequency detected by the maximum point frequency detection circuit as a reference point frequency A detection circuit, a smoothing circuit for smoothing a trajectory in the time direction of the reference point frequency detected by the maximum frequency detection circuit, and a phase correction amount from the trajectory in the time direction of the reference point frequency smoothed by the smoothing circuit. Phase correction amount calculation circuit to calculate, phase correction calculated by the phase correction amount calculation circuit Is obtained constituted by a phase correction circuit for correcting the phase of the target received signal output from the buffer circuit by using.

In a radar signal processing apparatus according to a thirteenth aspect of the present invention, the phase correction means stores the target reception signal corrected by the distance correction means and the initial distance between the radar and the target center of gravity, and is output from the storage means. A divided frequency analysis means for frequency-analyzing a target reception signal in a small section in the time direction at an initial distance between the radar and the target center of gravity, and an observation time in a time direction of the reception signal to be subjected to frequency analysis by the above-mentioned division frequency analysis means. Time expansion means for expanding the high frequency component removal means for removing high frequency components for the frequency and amplitude waveforms obtained by the above-mentioned division frequency analysis means,
A data cutout unit that cuts out the data of the frequency and amplitude waveforms output from the high frequency component removing unit based on a threshold value, and detects a point at which the cutoff frequency and amplitude waveform has a maximum, and detects the maximum point. It comprises a maximum point frequency detecting means for calculating a frequency, and a central frequency detecting means using a median of the frequencies detected by the maximum point frequency detecting means as a reference point frequency.

A radar signal processing apparatus according to a fourteenth invention is the radar signal processing apparatus according to the thirteenth invention, wherein the phase correction means includes a smoothing means for smoothing a trajectory in the time direction of the reference point frequency detected by the center frequency detection means, Phase correction amount calculating means for calculating a phase correction amount from a locus in the time direction of the reference point frequency smoothed by the smoothing means,
A phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means.

According to a fifteenth aspect of the present invention, in the radar signal processing apparatus according to the thirteenth aspect, the phase correction means includes a buffer circuit for storing the target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target reception signal at an initial distance between the radar output from the buffer circuit and the target center of gravity in a small section in the time direction, and a reception target when the frequency analysis is performed by the divided frequency analysis circuit A zeroing circuit for extending the observation time by inserting data of zero in the time direction of the signal, a low-pass filter for removing high-frequency components from the frequency and amplitude waveforms obtained by the above-mentioned divisional frequency analysis circuit,
A data cutout circuit for cutting out data on the waveform of the frequency and amplitude from which the high-frequency component has been removed by the low-pass filter, a threshold setting circuit for setting a threshold necessary for cutting out data with the data cutout circuit, A maximum point frequency detection circuit that detects a maximum point of the cut-out frequency and amplitude waveforms and calculates the frequency at that time, a center frequency having a median value of the frequencies detected by the maximum point frequency detection circuit as a reference point frequency A detection circuit, a smoothing circuit for smoothing a trajectory in the time direction of the reference point frequency detected by the center frequency detection circuit, and a phase correction amount from the trajectory in the time direction of the reference point frequency smoothed by the smoothing circuit. Phase correction amount calculation circuit to calculate, phase correction calculated by the phase correction amount calculation circuit Is obtained constituted by a phase correction circuit for correcting the phase of the target received signal output from the buffer circuit by using.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows an embodiment of the phase correction unit of the present invention in the radar signal processing device shown in FIG. In the figure, 4, R
S, RG, and RD are the same as those in FIGS. In the figure, 8, 9, 11, 12, 13 and GS are the same as those in FIG. Reference numeral 22 denotes a zeroing circuit for extending the observation time by inserting zero data in the time direction of the target reception signal when the frequency analysis is performed by the divided frequency analysis circuit 9.
Is a low-pass filter for removing high-frequency components from the frequency and amplitude waveforms obtained by the section frequency analysis circuit 9;
Is a data cutout circuit that cuts out data on the waveform of the frequency and amplitude from which the high-frequency component has been removed by the low-pass filter 23, 15 is a threshold setting circuit that sets a threshold necessary for cutting out data with the data cutout circuit 14, and 16 is A maximum point frequency detection circuit that detects a maximum point in the waveform of the frequency and amplitude extracted by the data extraction circuit 14 and calculates the frequency at that time. Reference numeral 17 denotes an average value of the frequencies detected by the maximum point frequency detection circuit 16. This is an average frequency detection circuit that serves as a reference point frequency.

Next, the operation of the phase corrector 4 configured as shown in FIG. 1 will be described. The target reception signal R in which the distance shift due to the time input from the distance correction unit 3 has been corrected.
S and the initial distance RG between the radar and the target center of gravity are stored in the buffer circuit 8, and output as the target reception signal RS and the target reception signal GS at the initial distance RG between the radar and the target center of gravity.

In the target reception signal GS at the initial distance RG between the radar and the target center of gravity, zero data is inserted in the time direction by the zeroing circuit 22 to extend the observation time. After the frequency analysis is performed in a small section, and the high-frequency component is further removed by the low-pass filter 23, each amplitude value is set by the data cutout circuit 14 with the threshold setting circuit 15 with respect to the obtained frequency and amplitude waveforms. Data is cut out for a region exceeding the threshold.

In the threshold setting circuit 15, for example, a fixed threshold for setting a constant threshold between the main lobe level and the side lobe level, a CFAR (Constant False Alarm Rate) for adaptively setting a threshold, and the like are used. A threshold is set for each waveform after frequency analysis. The local maximum frequency detecting circuit 16 detects all local maximums of the frequency and amplitude waveforms extracted by the data extracting circuit 14, and calculates the frequency at that time. The average frequency detection circuit 17 detects the average frequency as the reference point frequency for the frequencies at all the maximum points calculated by the maximum point frequency detection circuit 16, and outputs the detected frequency to the smoothing circuit 11.

The smoothing circuit 11 smoothes the locus of the reference point frequency in the time direction, and the phase correction amount calculating circuit 12 calculates the phase correction amount from the smoothed locus. The phase correction circuit 13 uses the phase correction amount calculated by the phase correction amount calculation circuit 12 to correct the phase of the target reception signal RS whose distance deviation due to time output from the buffer circuit 8 has been corrected,
The signal is output to the frequency analysis unit 5 as the target reception signal RD in which the phase shift due to time has been corrected.

Next, the phase corrector 4 configured as shown in FIG. 1 will be described with reference to FIGS. 15, 6, 7 and 8. FIG. 15 shows the processing method of the phase correction unit 4, FIG. 6 shows the operation of the zeroing circuit 22, and FIG.
8 is a diagram showing a method of detecting the maximum point frequency, and FIG. 8 is a diagram showing a method of detecting the reference point frequency in the average frequency detecting circuit 17.

S _{i, j} (where i is the range bin number, j is the pulse hit number, and i, j are natural numbers), the target received signal RS whose distance deviation due to time has been corrected, the radar and the target centroid If the range bin number where the initial distance RG exists is defined as r, the target reception signal GS at the initial distance RG between the radar and the target center of gravity is expressed as S _{r, j,} and FIG.
Is obtained. When frequency analysis of S _{r, j} is performed in a small section in the time direction (pulse hit direction) by the divided frequency analysis circuit 9, a waveform as shown in FIG. 15B is obtained, and the frequency f _m and the amplitude A _m ^k are obtained. (Where k is a division frequency analysis number, m is a frequency bin number, and k and m are natural numbers).
Is represented by “Equation 1”.

When frequency analysis is performed by the divisional frequency analysis circuit 9, data of 0 is inserted in the time direction of the target reception signal using the zeroing circuit 22 as shown in FIG. To expand. When the frequency of the zero-numbered received signal is analyzed by the division frequency analysis circuit 9, the frequency resolution is improved in accordance with the extended observation time as shown in FIG. 6B.

For example, assuming that the observation time of the target reception signal in the division frequency analysis circuit 9 is T, the frequency resolution Δf
Is given by “Equation 5”.

[0043]

(Equation 5)

Using the zeroing circuit 22 to extend the observation time of the target received signal by the divisional frequency analysis circuit 9 by 2 to 2T, the frequency resolution Δf ′ becomes “Equation 6”.
It can be seen that the frequency resolution is doubled as compared with “Equation 5”. Therefore, the detection accuracy of the local maximum point frequency in the local maximum point frequency detection circuit 16 at the subsequent stage is improved.

[0045]

(Equation 6)

In FIG. 6, zero is added after the target reception signal in the divided frequency analysis circuit 9, but it may be zero before or on both sides of the reception signal.

The frequency f _{m at} each section frequency analysis number k
The waveform of the amplitude A _m ^k is expressed as in FIG. 7 (a). FIG.
7B shows a waveform obtained by removing a high-frequency component from the waveform shown in FIG. In FIG. 7C, the frequency domain in which each amplitude value exceeds the threshold value set by the threshold value setting circuit 15 (for example, the dashed line u in FIG. 7C) with respect to the waveform shown in FIG. The data extraction circuit 14 performs data extraction, and then the maximum point frequency detection circuit 16 detects all the maximum points in the extracted frequency region, and determines the frequency at that time.
f ′ _n ^k (where n = 1,..., N, n is the maximum point number, N is the maximum point number, and n and N are natural numbers).

In the average frequency detecting circuit 17, the maximum point frequency detected by the maximum point frequency detecting circuit 16 as shown in FIG.
with f _'n ^k, calculates a reference-point frequency f ^k by "Number 7".

[0049]

(Equation 7)

FIG. 15 shows the relationship between time t _k and reference point frequency f ^k .
It becomes like the plot of (c). FIG.
When smoothing is performed on the plot of FIG.
Waveform shown by the solid line is obtained in (c), the time t _k and the frequency f ^'
The relationship of ^k is represented by “Equation 2”.

In the phase correction amount calculation circuit 12, the phase correction amount
W _j is calculated by “Equation 3”.

The phase correction circuit 13 corrects the phase of S _{i, j} by “Equation 4” using the phase correction amount W _j . However, the target received signal RD in which the phase shift due to time has been corrected is defined as S ′ _{i, j} .

Embodiment 2 In the embodiment shown in FIG. 2, as the reference point frequency detection means of the phase correction unit 4 in the first embodiment, the average frequency detection circuit 17 uses the center value of the frequency detected by the local maximum frequency detection circuit 16 as a reference. A center frequency detection circuit 18 which is a point frequency is replaced. According to such an embodiment, since the frequency resolution is improved in accordance with the observation time extended by the zeroing, the detection accuracy of the maximum point frequency is improved.

Since the high-frequency component is removed from the frequency and amplitude waveforms after the division frequency analysis by the low-pass filter 23, the reference point frequency is determined by focusing only on the frequency at the maximum point. Erroneous detection of the local maximum point due to the above, and a stable reference point frequency independent of the amplitude value of the waveform can be detected. Further, since the center frequency is detected from the frequency of the local maximum point, the calculation amount can be reduced.

Next, the operation of the phase corrector 4 configured as shown in FIG. 2 will be described. The target reception signal R in which the distance shift due to the time input from the distance correction unit 3 has been corrected.
S and the initial distance RG between the radar and the target center of gravity are stored in the buffer circuit 8, and output as the target reception signal RS and the target reception signal GS at the initial distance RG between the radar and the target center of gravity.

The target reception signal GS at the initial distance RG between the radar and the target center of gravity is inserted with zero data in the time direction by the zeroing circuit 22 and the observation time is extended. After the frequency analysis is performed in a small section, and the high-frequency component is further removed by the low-pass filter 23, each amplitude value is set by the data cutout circuit 14 with the threshold setting circuit 15 with respect to the obtained frequency and amplitude waveforms. Data is cut out for a region exceeding the threshold.

The threshold setting circuit 15 uses, for example, a fixed threshold for setting a constant threshold between the main lobe level and the side lobe level, a CFAR (Constant False Alarm Rate) for adaptively setting a threshold, and the like. A threshold is set for each waveform after frequency analysis. The local maximum frequency detecting circuit 16 detects all local maximums of the frequency and amplitude waveforms extracted by the data extracting circuit 14, and calculates the frequency at that time.

The center frequency detecting circuit 18 detects the center frequencies of the frequencies at all the local maximum points calculated by the local maximum point frequency detecting circuit 16 as the reference point frequencies, and outputs them to the smoothing circuit 11. The smoothing circuit 11 smoothes the locus of the reference point frequency in the time direction, and the phase correction amount calculating circuit 12 calculates the phase correction amount from the smoothed locus.

The phase correction circuit 13 is a phase correction amount calculation circuit 1
Using the phase correction amount calculated in step 2, the phase of the target received signal RS output from the buffer circuit 8 and corrected for the distance shift due to time is corrected, and the frequency analysis is performed as the target received signal RD corrected for the phase shift due to time. Output to the unit 5.

Next, the phase corrector 4 configured as shown in FIG. 2 will be described with reference to FIGS. FIG. 9 is a diagram showing a method of detecting the reference point frequency in the center frequency detection circuit 18. Frequency at each division frequency analysis number k
waveform f _m and the amplitude A _m ^k can be expressed as in FIG. 7 (a). FIG. 7B shows a waveform obtained by removing a high-frequency component from the waveform shown in FIG. In FIG. 7C, the frequency domain in which each amplitude value exceeds the threshold value set by the threshold value setting circuit 15 (for example, the dashed line u in FIG. 7C) with respect to the waveform shown in FIG. The data extraction circuit 14 performs data extraction, and then the maximum point frequency detection circuit 16 detects all the maximum points in the extracted frequency region, and determines the frequency at that time.
f ′ _n ^k (where n = 1,..., N, n is the maximum point number, N is the maximum point number, and n and N are natural numbers).

In the center frequency detecting circuit 18, the maximum point frequency detected by the maximum point frequency detecting circuit 16 as shown in FIG.
with f _'n ^k, calculates a reference-point frequency f ^k by "number 8".

[0062]

(Equation 8)

Embodiment 3 In the embodiment shown in FIG. 3, as the reference point frequency detecting means of the phase correction unit 4 in the first embodiment, the average frequency detecting circuit 17 uses the minimum value of the frequency detected by the local maximum frequency detecting circuit 16 as a reference. The minimum frequency detection circuit 19 for setting the point frequency is replaced.

According to such an embodiment, since the frequency resolution is improved in accordance with the observation time extended by the zeroing, the detection accuracy of the maximum point frequency is improved. Also, after removing the high-frequency components from the frequency and amplitude waveforms after the division frequency analysis by the low-pass filter 23, the reference point frequency is determined by focusing only on the frequency of the local maximum point. Erroneous detection, and a stable reference point frequency independent of the amplitude value of the waveform can be detected. Further, since the minimum frequency is detected from the frequency of the local maximum point, the amount of calculation can be reduced.

Next, the operation of the phase corrector 4 configured as shown in FIG. 3 will be described. The target reception signal R in which the distance shift due to the time input from the distance correction unit 3 has been corrected.
S and the initial distance RG between the radar and the target center of gravity are stored in the buffer circuit 8, and output as the target reception signal RS and the target reception signal GS at the initial distance RG between the radar and the target center of gravity.

The target reception signal GS at the initial distance RG between the radar and the target center of gravity is inserted with zero data in the time direction by the zeroing circuit 22 to extend the observation time. After the frequency analysis is performed in a small section, and the high-frequency component is further removed by the low-pass filter 23, each amplitude value is set by the data cutout circuit 14 with the threshold setting circuit 15 with respect to the obtained frequency and amplitude waveforms. Data is cut out for a region exceeding the threshold.

The threshold setting circuit 15 uses, for example, a fixed threshold for setting a constant threshold between the main lobe level and the side lobe level, and a CFAR (Constant False Alarm Rate) for adaptively setting a threshold. A threshold is set for each waveform after frequency analysis. The local maximum frequency detecting circuit 16 detects all local maximums of the frequency and amplitude waveforms extracted by the data extracting circuit 14, and calculates the frequency at that time.

The minimum frequency detection circuit 19 detects the minimum frequencies as the reference point frequencies for the frequencies at all the maximum points calculated by the maximum point frequency detection circuit 16 and outputs the detected frequencies to the smoothing circuit 11. The smoothing circuit 11 smoothes the locus of the reference point frequency in the time direction, and the phase correction amount calculating circuit 12 calculates the phase correction amount from the smoothed locus.

The phase correction circuit 13 is a phase correction amount calculation circuit 1
Using the phase correction amount calculated in step 2, the phase of the target received signal RS output from the buffer circuit 8 and corrected for the distance shift due to time is corrected, and the frequency analysis is performed as the target received signal RD corrected for the phase shift due to time. Output to the unit 5.

Next, the phase corrector 4 configured as shown in FIG. 3 will be described with reference to FIGS. FIG. 10 is a diagram showing a method of detecting the reference point frequency in the minimum frequency detection circuit 19. Waveform of the frequency f _m and the amplitude A _m ^k at each division frequency analysis number k is represented as shown in FIG. 7 (a). FIG. 7B shows a waveform obtained by removing a high-frequency component from the waveform shown in FIG. In FIG. 7C, the frequency domain in which each amplitude value exceeds the threshold value set by the threshold value setting circuit 15 (for example, the dashed line u in FIG. 7C) with respect to the waveform shown in FIG. performs data extraction with data extraction circuit 14 for, detect all local maximum points for the next cut the frequency domain at the maximum point frequency detection circuit 16, a frequency f _'n ^k at that time (here, n = 1, · , N, where n is the maximum point number, N is the maximum point number, and n and N are natural numbers.

[0071] In the minimum frequency detecting circuit 19, using a maximum point frequency f _'n ^k detected by the maximum point frequency detecting circuit 16 as shown in FIG. 10, and calculates the reference point frequency f ^k by "Number 9".

[0072]

(Equation 9)

Embodiment 4 In the embodiment shown in FIG. 4, as the reference point frequency detecting means of the phase correction unit 4 in the first embodiment, the average frequency detecting circuit 17 uses the maximum value of the frequency detected by the local maximum frequency detecting circuit 16 as a reference. The maximum frequency detection circuit 20 for setting the point frequency is replaced.

According to such an embodiment, since the frequency resolution is improved in accordance with the observation time extended by the zeroing, the detection accuracy of the maximum point frequency is improved. Also, after removing the high-frequency components from the frequency and amplitude waveforms after the division frequency analysis by the low-pass filter 23, the reference point frequency is determined by focusing only on the frequency of the local maximum point. Erroneous detection, and a stable reference point frequency independent of the amplitude value of the waveform can be detected. Further, since the maximum frequency is detected from the frequency of the local maximum point, the amount of calculation can be reduced.

Next, the operation of the phase corrector 4 configured as shown in FIG. 4 will be described. The target reception signal R in which the distance shift due to the time input from the distance correction unit 3 has been corrected.
S and the initial distance RG between the radar and the target center of gravity are stored in the buffer circuit 8, and output as the target reception signal RS and the target reception signal GS at the initial distance RG between the radar and the target center of gravity.

The target reception signal GS at the initial distance RG between the radar and the target center of gravity is inserted with zero data in the time direction by the zeroing circuit 22 to extend the observation time. After the frequency analysis is performed in a small section, and the high-frequency component is further removed by the low-pass filter 23, each amplitude value is set by the data cutout circuit 14 with the threshold setting circuit 15 with respect to the obtained frequency and amplitude waveforms. Data is cut out for a region exceeding the threshold.

The threshold setting circuit 15 uses, for example, a fixed threshold for setting a constant threshold between the main lobe level and the side lobe level, and a CFAR (Constant False Alarm Rate) for adaptively setting a threshold. A threshold is set for each waveform after frequency analysis. The local maximum frequency detecting circuit 16 detects all local maximums of the frequency and amplitude waveforms extracted by the data extracting circuit 14, and calculates the frequency at that time.

The maximum frequency detection circuit 20 detects the maximum frequencies as the reference point frequencies for the frequencies at all the maximum points calculated by the maximum point frequency detection circuit 16 and outputs the detected frequencies to the smoothing circuit 11. The smoothing circuit 11 smoothes the locus of the reference point frequency in the time direction, and the phase correction amount calculating circuit 12 calculates the phase correction amount from the smoothed locus.

The phase correction circuit 13 is a phase correction amount calculation circuit 1
Using the phase correction amount calculated in step 2, the phase of the target received signal RS output from the buffer circuit 8 and corrected for the distance shift due to time is corrected, and the frequency analysis is performed as the target received signal RD corrected for the phase shift due to time. Output to the unit 5.

Next, the phase corrector 4 configured as shown in FIG. 4 will be described with reference to FIGS. FIG. 11 is a diagram illustrating a method of detecting the reference point frequency in the maximum frequency detection circuit 20. Waveform of the frequency f _m and the amplitude A _m ^k at each division frequency analysis number k is represented as shown in FIG. 7 (a). FIG. 7B shows a waveform obtained by removing a high-frequency component from the waveform shown in FIG. In FIG. 7C, the frequency domain in which each amplitude value exceeds the threshold value set by the threshold value setting circuit 15 (for example, the dashed line u in FIG. 7C) with respect to the waveform shown in FIG. performs data extraction with data extraction circuit 14 for, detect all local maximum points for the next cut the frequency domain at the maximum point frequency detection circuit 16, a frequency f _'n ^k at that time (here, n = 1, · , N, where n is the maximum point number, N is the maximum point number, and n and N are natural numbers.

[0081] In the maximum frequency detecting circuit 20, using a maximum point frequency f _'n ^k detected by the maximum point frequency detecting circuit 16 as shown in FIG. 11, and calculates the reference point frequency f ^k by "number 10".

[0082]

(Equation 10)

Embodiment 5 In the embodiment shown in FIG. 5, as the reference point frequency detecting means of the phase correction unit 4 in the first embodiment, the average frequency detecting circuit 17 uses the median of the frequencies detected by the local maximum frequency detecting circuit 16 as a reference. It is replaced by a center frequency detection circuit 21 which is a point frequency.

According to such an embodiment, since the frequency resolution is improved in accordance with the observation time extended by the zeroing, the detection accuracy of the maximum point frequency is improved. Also, after removing the high-frequency components from the frequency and amplitude waveforms after the division frequency analysis by the low-pass filter 23, the reference point frequency is determined by focusing only on the frequency of the local maximum point. Erroneous detection, and a stable reference point frequency independent of the amplitude value of the waveform can be detected. Further, since the center frequency is detected from the frequency at the maximum point, the amount of calculation can be reduced.

Next, the operation of the phase corrector 4 configured as shown in FIG. 5 will be described. The target reception signal R in which the distance shift due to the time input from the distance correction unit 3 has been corrected.
S and the initial distance RG between the radar and the target center of gravity are stored in the buffer circuit 8, and output as the target reception signal RS and the target reception signal GS at the initial distance RG between the radar and the target center of gravity.

The target reception signal GS at the initial distance RG between the radar and the target center of gravity is inserted with zero data in the time direction by the zeroing circuit 22 to extend the observation time. After the frequency analysis is performed in a small section, and the high-frequency component is further removed by the low-pass filter 23, each amplitude value is set by the data cutout circuit 14 with the threshold setting circuit 15 with respect to the obtained frequency and amplitude waveforms. Data is cut out for a region exceeding the threshold.

The threshold setting circuit 15 uses, for example, a fixed threshold for setting a constant threshold between the main lobe level and the side lobe level, a CFAR (Constant False Alarm Rate) for adaptively setting a threshold, and the like. A threshold is set for each waveform after frequency analysis. The local maximum frequency detecting circuit 16 detects all local maximums of the frequency and amplitude waveforms extracted by the data extracting circuit 14, and calculates the frequency at that time.

The center frequency detecting circuit 21 detects the center frequencies of the frequencies at all the local maximum points calculated by the local maximum point frequency detecting circuit 16 as the reference point frequencies, and then outputs them to the smoothing circuit 11. The smoothing circuit 11 smoothes the locus of the reference point frequency in the time direction, and the phase correction amount calculating circuit 12 calculates the phase correction amount from the smoothed locus.

The phase correction circuit 13 is a phase correction amount calculation circuit 1
Using the phase correction amount calculated in step 2, the phase of the target received signal RS output from the buffer circuit 8 and corrected for the distance shift due to time is corrected, and the frequency analysis is performed as the target received signal RD corrected for the phase shift due to time. Output to the unit 5.

Next, the phase corrector 4 configured as shown in FIG. 5 will be described with reference to FIGS. FIG. 12 is a diagram showing a method of detecting the reference point frequency in the center frequency detection circuit 21. Waveform of the frequency f _m and the amplitude A _m ^k at each division frequency analysis number k is represented as shown in FIG. 7 (a). FIG. 7B shows a waveform obtained by removing a high-frequency component from the waveform shown in FIG. In FIG. 7C, the frequency domain in which each amplitude value exceeds the threshold value set by the threshold value setting circuit 15 (for example, the dashed line u in FIG. 7C) with respect to the waveform shown in FIG. performs data extraction with data extraction circuit 14 for, detect all local maximum points for the next cut the frequency domain at the maximum point frequency detection circuit 16, a frequency f _'n ^k at that time (here, n = 1, · , N, where n is the maximum point number, N is the maximum point number, and n and N are natural numbers.

[0091] In the central frequency detection circuit 21, using a maximum point frequency f _'n ^k detected by the maximum point frequency detection circuit 16 calculates a reference-point frequency f ^k by "number 11".

[0092]

[Equation 11]

When the maximum number N of points is an odd number on the right side of “Equation 11,” (1 + N) / 2 = n is an integer.
The corresponding maximum point frequency f _'n ^k is present. Therefore, the reference point frequency ^fk can be easily calculated. However, if the maximum number N is even, (1 + N) / 2 = n is not an integer (not divisible by 2, a real number) for the corresponding maximum point frequency f _'n ^k does not exist. Therefore, when the maximum number of points N is an even number, for example, of the following methods,
The reference point frequency ^fk may be calculated by any method.

A method of rounding down the decimal point of (1 + N) / 2 to “Expression 12”, a method of rounding up the decimal point of (1 + N) / 2 to “Expression 13”, “Expression 12” and “Expression 13” of “Expression 14” Is shown. In FIG. 12, the reference point frequency f ^k is calculated using “Equation 14”.

[0095]

(Equation 12)

[0096]

(Equation 13)

[0097]

[Equation 14]

[0098]

According to the first to third aspects of the present invention, the frequency resolution is improved according to the observation time, so that the detection accuracy of the maximum point frequency is improved. In addition, after removing high-frequency components from the frequency and amplitude waveforms after the segmented frequency analysis, data is cut out based on the set thresholds, and the average value of the frequencies at all the local maximum points is focused on the local maximum points of the extracted waveform. Since detection is performed as a point frequency, erroneous detection of a maximum point due to a high-frequency component can be reduced. Furthermore, even when the waveform of the frequency and the amplitude is multi-peak and the position of the peak where the amplitude value is maximum fluctuates greatly with time, it is hardly affected by the fluctuation, and the reference point frequency is detected stably. Thus, there is an effect that blur and blur of an image can be removed.

In the fourth to sixth inventions, the frequency resolution is improved in accordance with the extended observation time, so that the detection accuracy of the maximum point frequency is improved. In addition, after removing high-frequency components from the frequency and amplitude waveforms after the segmented frequency analysis, data is cut out based on the set threshold, and the center value of the frequency at all the maximal points is focused on by focusing on the maximal points of the cut out waveform. Since the detection is performed as the point frequency, erroneous detection of the maximum point due to the high frequency component can be reduced and the amount of calculation can be reduced. Furthermore, even when the waveform of the frequency and the amplitude is multi-peak and the position of the peak where the amplitude value is maximum fluctuates greatly with time, it is hardly affected by the fluctuation, and the reference point frequency is detected stably. Thus, there is an effect that blur and blur of an image can be removed.

In the seventh to ninth aspects, the frequency resolution is improved in accordance with the extended observation time, so that the detection accuracy of the maximum point frequency is improved. Also, after removing high-frequency components from the frequency and amplitude waveforms after the segmented frequency analysis using a low-pass filter, cut out data based on the set threshold, and pay attention to the local maximum points of the cut-out waveform. Is detected as the reference point frequency,
It is possible to reduce the erroneous detection of the maximum point due to the high frequency component and to reduce the amount of calculation. Furthermore, even when the waveform of the frequency and the amplitude is multi-peak and the position of the peak where the amplitude value is maximum fluctuates greatly with time, it is hardly affected by the fluctuation, and the reference point frequency is detected stably. Thus, there is an effect that blur and blur of an image can be removed.

In the tenth to twelfth inventions, the frequency resolution is improved in accordance with the extended observation time, so that the detection accuracy of the maximum point frequency is improved. Also, after removing high-frequency components from the frequency and amplitude waveforms after the segmented frequency analysis using a low-pass filter, cut out data based on the set threshold, and pay attention to the local maximum points of the cut-out waveform. Is detected as the reference point frequency, so that the erroneous detection of the local maximum point due to the high frequency component can be reduced and the calculation amount can be reduced. Furthermore, even when the waveform of the frequency and the amplitude is multi-peak and the position of the peak where the amplitude value is maximum fluctuates greatly with time, it is hardly affected by the fluctuation, and the reference point frequency is detected stably. Thus, there is an effect that blur and blur of an image can be removed.

In the thirteenth to fifteenth aspects, the frequency resolution is improved in accordance with the extended observation time, so that the detection accuracy of the maximum point frequency is improved. Also, after removing high-frequency components from the frequency and amplitude waveforms after the segmented frequency analysis using a low-pass filter, cut out data based on the set threshold, and pay attention to the local maximum points of the cut-out waveform. Is detected as the reference point frequency, so that erroneous detection of the local maximum point due to the high frequency component can be reduced and the calculation amount can be reduced. Furthermore, even when the waveform of the frequency and the amplitude is multi-peak, and the position of the peak at which the amplitude value is maximum fluctuates greatly with time, it is hardly affected by the fluctuation,
There is an effect that the reference point frequency can be stably detected, and blur and blur of an image can be removed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a phase correction unit according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of a phase correction unit according to the second embodiment of the present invention.

FIG. 3 is a configuration diagram of a phase correction unit according to the third embodiment of the present invention.

FIG. 4 is a configuration diagram of a phase correction unit according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of a phase correction unit according to the fifth embodiment of the present invention.

FIG. 6 is a diagram illustrating an operation of a zero-based circuit.

FIG. 7 is a diagram illustrating an operation of a low-pass filter and a method of detecting a maximum point frequency.

FIG. 8 is a diagram illustrating a method of detecting a reference point frequency in an average frequency detection circuit.

FIG. 9 is a diagram illustrating a method of detecting a reference point frequency in a center frequency detection circuit.

FIG. 10 is a diagram illustrating a method of detecting a reference point frequency in a minimum frequency detection circuit.

FIG. 11 is a diagram illustrating a method of detecting a reference point frequency in a maximum frequency detection circuit.

FIG. 12 is a diagram illustrating a method of detecting a reference point frequency in a center frequency detection circuit.

FIG. 13 is a configuration diagram of a radar signal processing device in the high-resolution radar device.

FIG. 14 is a configuration diagram of a conventional phase correction unit.

FIG. 15 is a diagram illustrating a processing method of a phase correction unit.

[Explanation of symbols]

Reference Signs List 1 data interface unit, 2 pulse compression unit, 3 distance correction unit, 4 phase correction unit, 5 frequency analysis unit, 6 detection unit, 7 display interface unit, 8 buffer circuit, 9
Classification frequency analysis circuit, 10 Maximum amplitude value detection circuit, 11
Smoothing circuit, 12 phase correction amount calculation circuit, 13 phase correction circuit, 14 data cutout circuit, 15 threshold value setting circuit, 16 maximum point frequency detection circuit, 17 average frequency detection circuit, 18 center frequency detection circuit, 19 minimum frequency detection circuit , 20 maximum frequency detection circuit, 21 center frequency detection circuit, 220 fold circuit, 23 low pass filter.

Claims (15)

[Claims] 1. A pulse compression means for pulse-compressing a target reception signal input from a radar apparatus, a distance correction means for correcting a time-dependent distance shift of the target reception signal pulse-compressed by the pulse compression means, and the distance A radar signal processing device comprising: a phase correction unit that corrects a phase shift due to time of the target reception signal corrected by the correction unit; wherein the phase correction unit includes the target reception signal and the radar corrected by the distance correction unit. Storage means for storing an initial distance from the target center of gravity, a divided frequency analysis means for frequency-analyzing a target reception signal at an initial distance between the radar and the target center of gravity output from the storage means in a small section in the time direction,
Time extension means for extending the observation time in the time direction of a reception signal to be subjected to frequency analysis by the divided frequency analysis means, and high frequency for removing high frequency components from the frequency and amplitude waveforms obtained by the divided frequency analysis means Component removing means, data extracting means for extracting data of the frequency and amplitude waveforms output from the high-frequency component removing means on the basis of a threshold, detecting a point at which the extracted frequency and amplitude waveforms have a maximum, and detecting the maximum. Radar signal processing, comprising: a maximum point frequency detecting means for calculating a frequency of a point to be obtained; and an average frequency detecting means using an average value of the frequencies detected by the maximum point frequency detecting means as a reference point frequency. apparatus. 2. The phase correction means includes: a smoothing means for smoothing a trajectory of the reference point frequency detected by the average frequency detection means in a time direction; and a time of the reference point frequency smoothed by the smoothing means. Phase correction amount calculation means for calculating a phase correction amount from a trajectory in a direction, and a phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means The radar signal processing apparatus according to claim 1, further comprising: 3. A buffer circuit for storing a target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity, and a phase difference between the radar output from the buffer circuit and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target received signal at an initial distance in a small section in the time direction, and inserting 0 data in the time direction of a target received signal when frequency analysis is performed by the above-described divided frequency analysis circuit, and observing time. A low-pass filter that removes high-frequency components from the frequency and amplitude waveforms obtained by the above-described divided frequency analysis circuit, and a frequency and amplitude waveform from which high-frequency components are removed by the low-pass filter. A data extraction circuit for extracting data, and a threshold setting for setting a threshold necessary for extracting data by the data extraction circuit. A constant circuit, a maximum point frequency detection circuit that detects a maximum point in the frequency and amplitude waveforms cut out by the data extraction circuit and calculates the frequency at that time, and an average value of the frequencies detected by the maximum point frequency detection circuit. An average frequency detection circuit having a reference point frequency, a smoothing circuit for smoothing a trajectory in the time direction of the reference point frequency detected by the average frequency detection circuit,
A phase correction amount calculating circuit for calculating a phase correction amount from a locus in the time direction of the reference point frequency smoothed by the smoothing circuit; and the buffer circuit using the phase correction amount calculated by the phase correction amount calculating circuit. 2. The radar signal processing device according to claim 1, further comprising a phase correction circuit for correcting the phase of the output target reception signal. 4. A pulse compression means for pulse-compressing a target reception signal input from a radar device, a distance correction means for correcting a time-dependent distance shift of the target reception signal pulse-compressed by the pulse compression means, and the distance A radar signal processing device comprising: a phase correction unit that corrects a phase shift due to time of the target reception signal corrected by the correction unit; wherein the phase correction unit includes the target reception signal and the radar corrected by the distance correction unit. Storage means for storing an initial distance from the target center of gravity, a divided frequency analysis means for frequency-analyzing a target reception signal at an initial distance between the radar and the target center of gravity output from the storage means in a small section in the time direction,
Time extension means for extending the observation time in the time direction of a reception signal to be subjected to frequency analysis by the divided frequency analysis means, and high frequency for removing high frequency components from the frequency and amplitude waveforms obtained by the divided frequency analysis means Component removing means, data extracting means for extracting data of the frequency and amplitude waveforms output from the high-frequency component removing means on the basis of a threshold, detecting a point at which the extracted frequency and amplitude waveforms have a maximum, and detecting the maximum. Radar signal processing comprising: a maximum point frequency detecting means for calculating a frequency of a point to be obtained; and a central frequency detecting means for setting a center value of the frequency detected by the maximum point frequency detecting means to a reference point frequency. apparatus. 5. The phase correction means includes: a smoothing means for smoothing a trajectory of the reference point frequency detected by the center frequency detection means in a time direction; and a time of the reference point frequency smoothed by the smoothing means. Phase correction amount calculation means for calculating a phase correction amount from a trajectory in a direction, and a phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means 5. The radar signal processing device according to claim 4, comprising: 6. A buffer circuit for storing a target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity, and a phase difference between the radar output from the buffer circuit and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target received signal at an initial distance in a small section in the time direction, and inserting 0 data in the time direction of a target received signal when frequency analysis is performed by the above-described divided frequency analysis circuit, and observing time. A low-pass filter that removes high-frequency components from the frequency and amplitude waveforms obtained by the above-described divided frequency analysis circuit, and a frequency and amplitude waveform from which high-frequency components are removed by the low-pass filter. A data extraction circuit for extracting data, and a threshold setting for setting a threshold necessary for extracting data by the data extraction circuit. A constant circuit, a maximum point frequency detection circuit that detects a maximum point for the frequency and amplitude waveforms cut out by the data extraction circuit and calculates the frequency at that time, and a center value of the frequency detected by the maximum point frequency detection circuit. A center frequency detection circuit having a reference point frequency, a smoothing circuit for smoothing a locus in the time direction of the reference point frequency detected by the center frequency detection circuit,
A phase correction amount calculating circuit for calculating a phase correction amount from a locus in the time direction of the reference point frequency smoothed by the smoothing circuit; and the buffer circuit using the phase correction amount calculated by the phase correction amount calculating circuit. 5. The radar signal processing device according to claim 4, further comprising a phase correction circuit for correcting the phase of the output target reception signal. 7. A pulse compression means for pulse-compressing a target reception signal input from a radar device, a distance correction means for correcting a time-dependent distance shift of the target reception signal pulse-compressed by the pulse compression means, and the distance A radar signal processing device comprising: a phase correction unit that corrects a phase shift due to time of the target reception signal corrected by the correction unit; wherein the phase correction unit includes the target reception signal and the radar corrected by the distance correction unit. Storage means for storing an initial distance from the target center of gravity, a divided frequency analysis means for frequency-analyzing a target reception signal at an initial distance between the radar and the target center of gravity output from the storage means in a small section in the time direction,
Time extension means for extending the observation time in the time direction of a reception signal to be subjected to frequency analysis by the divided frequency analysis means, and high frequency for removing high frequency components from the frequency and amplitude waveforms obtained by the divided frequency analysis means Component removing means, data extracting means for extracting data of the frequency and amplitude waveforms output from the high-frequency component removing means on the basis of a threshold, detecting a point at which the extracted frequency and amplitude waveforms have a maximum, and detecting the maximum. Radar signal processing comprising: a maximum point frequency detecting means for calculating a frequency of a point to be obtained; and a minimum frequency detecting means using a minimum value of the frequency detected by the maximum point frequency detecting means as a reference point frequency. apparatus. 8. The phase correction means includes: a smoothing means for smoothing a trajectory of the reference point frequency detected by the minimum frequency detection means in a time direction; and a time of the reference point frequency smoothed by the smoothing means. Phase correction amount calculation means for calculating a phase correction amount from a trajectory in a direction, and a phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means The radar signal processing device according to claim 7, comprising: 9. A buffer circuit for storing the target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity, and a phase difference between the radar output from the buffer circuit and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target received signal at an initial distance in a small section in the time direction, and inserting 0 data in the time direction of a target received signal when frequency analysis is performed by the above-described divided frequency analysis circuit, and observing time. A low-pass filter that removes high-frequency components from the frequency and amplitude waveforms obtained by the above-described divided frequency analysis circuit, and a frequency and amplitude waveform from which high-frequency components are removed by the low-pass filter. A data extraction circuit for extracting data, and a threshold setting for setting a threshold necessary for extracting data by the data extraction circuit. A constant circuit, a maximum point frequency detection circuit that detects a maximum point in the waveform of the frequency and amplitude extracted by the data extraction circuit and calculates the frequency at that time, and a minimum value of the frequency detected by the maximum point frequency detection circuit. A minimum frequency detection circuit having a reference point frequency, a smoothing circuit for smoothing a locus in the time direction of the reference point frequency detected by the minimum frequency detection circuit,
A phase correction amount calculating circuit for calculating a phase correction amount from a locus in the time direction of the reference point frequency smoothed by the smoothing circuit; and the buffer circuit using the phase correction amount calculated by the phase correction amount calculating circuit. 8. The radar signal processing device according to claim 7, further comprising a phase correction circuit for correcting the phase of the output target reception signal. 10. A pulse compression means for pulse-compressing a target reception signal input from a radar device, a distance correction means for correcting a time-dependent distance shift of the target reception signal pulse-compressed by the pulse compression means, and the distance A radar signal processing device comprising: a phase correction unit that corrects a phase shift due to time of the target reception signal corrected by the correction unit; wherein the phase correction unit includes the target reception signal and the radar corrected by the distance correction unit. Storage means for storing an initial distance from the target center of gravity, a divided frequency analysis means for frequency-analyzing a target received signal output from the storage means at an initial distance between the radar and the target center of gravity in a small section in the time direction, Time extending means for extending an observation time in a time direction of a received signal to be subjected to frequency analysis by means, A high-frequency component removing unit that removes high-frequency components from the frequency and amplitude waveforms obtained by the frequency analyzing unit; a data extracting unit that extracts data based on a threshold from the frequency and amplitude waveforms output from the high-frequency component removing unit; A maximum point frequency detecting means for detecting a maximum point of the cut-out frequency and amplitude waveforms and calculating a frequency of the maximum point, and a maximum value of the frequency detected by the maximum point frequency detecting means as a reference point. A radar signal processing device comprising: a maximum frequency detecting means for setting a frequency. 11. The phase correction means includes: a smoothing means for smoothing a trajectory of the reference point frequency detected by the maximum frequency detection means in a time direction; and a time of the reference point frequency smoothed by the smoothing means. Phase correction amount calculation means for calculating a phase correction amount from a trajectory in a direction, and a phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means 2. The method according to claim 1, further comprising:
0. A radar signal processing apparatus according to item 0. 12. A buffer circuit for storing a target reception signal corrected by the distance correction means and an initial distance between the radar and the target center of gravity, and a phase difference between the radar output from the buffer circuit and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target received signal at an initial distance in a small section in the time direction, and inserting 0 data in the time direction of a target received signal when frequency analysis is performed by the above-described divided frequency analysis circuit, and observing time. A low-pass filter that removes high-frequency components from the frequency and amplitude waveforms obtained by the above-described divided frequency analysis circuit, and a frequency and amplitude waveform from which high-frequency components are removed by the low-pass filter. A data extraction circuit for extracting data,
A threshold setting circuit for setting a threshold necessary when data is cut out by the data cut-out circuit, a local maximum frequency for detecting a point where a waveform of the frequency and amplitude cut out by the data cut-out circuit becomes a maximum and calculating a frequency at that time A detection circuit, a maximum frequency detection circuit that uses the maximum value of the frequency detected by the local maximum frequency detection circuit as a reference point frequency, and a smoothing unit that smoothes a locus in the time direction of the reference point frequency detected by the maximum frequency detection circuit. Circuit,
A phase correction amount calculating circuit for calculating a phase correction amount from a locus in the time direction of the reference point frequency smoothed by the smoothing circuit; and the buffer circuit using the phase correction amount calculated by the phase correction amount calculating circuit. 11. The radar signal processing device according to claim 10, further comprising a phase correction circuit that corrects the phase of the output target reception signal. 13. A pulse compression means for pulse-compressing a target reception signal input from a radar device, a distance correction means for correcting a time-dependent distance shift of the target reception signal pulse-compressed by the pulse compression means, and the distance A radar signal processing device comprising: a phase correction unit that corrects a phase shift due to time of the target reception signal corrected by the correction unit; wherein the phase correction unit includes the target reception signal and the radar corrected by the distance correction unit. Storage means for storing an initial distance from the target center of gravity, a divided frequency analysis means for frequency-analyzing a target received signal output from the storage means at an initial distance between the radar and the target center of gravity in a small section in the time direction, Time extending means for extending an observation time in a time direction of a reception signal to be subjected to frequency analysis by means, A high-frequency component removing unit that removes high-frequency components from the frequency and amplitude waveforms obtained by the frequency analyzing unit; a data extracting unit that extracts data based on a threshold from the frequency and amplitude waveforms output from the high-frequency component removing unit; A maximum point frequency detecting means for detecting a local maximum point of the cut-out frequency and amplitude waveforms and calculating the frequency of the local maximum point, and a median value of the frequencies detected by the local maximum frequency detecting means as a reference point. A radar signal processing device comprising: a center frequency detecting means for setting a frequency. 14. The phase correction means includes: a smoothing means for smoothing a trajectory of the reference point frequency detected by the center frequency detection means in a time direction; and a time of the reference point frequency smoothed by the smoothing means. Phase correction amount calculation means for calculating a phase correction amount from a trajectory in a direction, and a phase correction circuit for correcting the phase of the target reception signal output from the storage means using the phase correction amount calculated by the phase correction amount calculation means 2. The method according to claim 1, further comprising:
4. The radar signal processing device according to 3. 15. A buffer circuit for storing a target reception signal corrected by the distance correction means and an initial distance between a radar and a target center of gravity, and a phase shifter between the radar output from the buffer circuit and the target center of gravity. A divided frequency analysis circuit for frequency-analyzing a target received signal at an initial distance in a small section in the time direction, and inserting 0 data in the time direction of a target received signal when frequency analysis is performed by the above-described divided frequency analysis circuit, and observing time. A low-pass filter that removes high-frequency components from the frequency and amplitude waveforms obtained by the above-described divided frequency analysis circuit, and a frequency and amplitude waveform from which high-frequency components are removed by the low-pass filter. A data extraction circuit for extracting data,
A threshold setting circuit for setting a threshold necessary when data is cut out by the data cut-out circuit, a local maximum frequency for detecting a point where a waveform of the frequency and amplitude cut out by the data cut-out circuit becomes a maximum and calculating a frequency at that time A detection circuit, a center frequency detection circuit that uses a median of the frequencies detected by the local maximum frequency detection circuit as a reference point frequency, and a smoothing unit that smoothes a locus in the time direction of the reference point frequency detected by the center frequency detection circuit. Circuit,
A phase correction amount calculating circuit for calculating a phase correction amount from a locus in the time direction of the reference point frequency smoothed by the smoothing circuit; and the buffer circuit using the phase correction amount calculated by the phase correction amount calculating circuit. 14. The radar signal processing device according to claim 13, further comprising a phase correction circuit that corrects the phase of the output target reception signal.