KR102156490B1 - Image decoding apparatus based on airborn and differential method of decoding image using the same - Google Patents

Abstract

Aircraft-based segmented image restoration device includes waveform generator, distributor, antenna member, mixer, raw data generation unit, vibration correction unit, preliminary reverse projection unit, preliminary image restoration unit, distance direction rotation component detection unit, azimuth direction rotation component detection unit, and correction data. It includes a generator. The shaking motion correction unit is connected to the raw data generation unit, and generates a plurality of partition raw data by dividing the raw data according to a preset spatial reference value. The preliminary reverse projection unit calculates a plurality of pre-correction reverse projection functions by performing a matching filter process for each segment raw data. The distance direction rotation component detector sets an angle in which the distance direction component of each of the segment preliminary images is inclined from an ideal distance direction as the distance direction rotation angle of the corresponding segment preliminary image. The azimuth direction rotation component detection unit sets an angle in which the azimuth direction component of each segment preliminary image is inclined from an ideal azimuth direction as an azimuth direction rotation angle of the corresponding segment preliminary image. The correction data generator corrects the positions of each of the pixels using the distance direction rotation angle and the azimuth rotation angle for each division preliminary image, and matches each division preliminary image according to the corrected position of each pixel. A filtering process is performed to generate the corrected reverse projection function for each pixel as corrected segment data.

Description

Aircraft-based segmented image restoration device and segmented image restoration method using the same {IMAGE DECODING APPARATUS BASED ON AIRBORN AND DIFFERENTIAL METHOD OF DECODING IMAGE USING THE SAME}

The present invention relates to an aircraft-based segmented image restoration apparatus and a segmented image restoration method using the same, and more particularly, to a Squint Error of FMCW-SAR (Frequency Modulated Continuous Wave-Synthetic Aperture Radar) data measured by an aircraft. ), and a split image restoration method using the same.

The global environment survey is a field that investigates geology, oceans, and ecology of a vast area, and includes field surveys, indoor experiments, and remote sensing.

Site surveys include direct visits to sites such as surface exploration, boring, and physical exploration, and surveys using the naked eye or various survey equipment. Because of its high accuracy, field surveys are still widely used when precise measurements are required. In indoor experiments, chemical and physical properties that are difficult to measure directly in the field are measured using precision measuring equipment in the laboratory. Field surveys and indoor experiments have the advantage of high accuracy, but due to temporal and spatial constraints, they are not easy to apply to large areas, remote areas, remote areas, and oceans.

In recent years, due to the development of remote sensing technology, remote sensing using aircraft has been widely used. In particular, remote sensing is very useful in disaster situations such as volcanic eruptions, earthquakes, typhoons, and environmental monitoring such as glaciers, tides, waves, and marine pollution.

General remote sensing equipment uses satellites or radar mounted on aircraft. In the case of an artificial satellite, it is possible to measure a large area from a distance, but it is difficult to obtain precise data because it is expensive and the distance from the measurement point is far.

In the case of an aircraft, it has the advantage of being able to measure near-distance at a relatively low price compared to satellites. However, during the operation of the aircraft, continuous fluctuations and vibrations occur due to atmospheric conditions, weather, engines, etc. The vibration and vibration of the aircraft degrade the quality of the data, but it is impossible to completely eliminate them due to the nature of the aircraft operating in the air.

Among these problems, especially when a squint error occurs due to a twisting of the radar's irradiation direction, the azimuth direction and the distance direction are twisted at the same time due to the fact that the data obtained through the aircraft has a three-dimensional shape, There is a problem that the data itself cannot be used.

Moreover, it has been known that data correction is very difficult when there is not only an orientation angle error, but also the vibration of the aircraft, and since there are many errors in the result of the correction attempt, it is virtually impossible to reuse.

This is a problem that cannot be solved even by cross-validation of data, and conventionally, when a heading angle error appears in data inspection, the data is discarded and the SAR radar is physically corrected to collect flight data again.

However, there is a need for technology development for correcting the orientation angle error, because a considerable cost is required to operate the aircraft.

Korean Patent Registration No. 10-1785684 (2017. 9. 29.)

An object of the present invention is to provide a segmented image restoration apparatus for correcting a Squint Error of FMCW-SAR (Frequency Modulated Continuous Wave-Synthetic Aperture Radar) data measured by an aircraft.

An object of the present invention is to provide a segmented image restoration method using a segmented image restoration apparatus for correcting a Squint Error of FMCW-SAR (Frequency Modulated Continuous Wave-Synthetic Aperture Radar) data measured by an aircraft.

An aircraft-based segmented image restoration apparatus according to an embodiment of the present invention includes a waveform generator, a distributor, an antenna member, a mixer, a raw data generation unit, a rotation correction unit, a preliminary reverse projection unit, a preliminary image restoration unit, a distance direction rotation component detection unit, and a bearing. And a direction rotation component detection unit, and a correction data generation unit. The waveform generator generates a signal having the same waveform as the transmission wave. The divider is connected to the waveform generator, and receives and distributes a signal generated from the waveform generator. The antenna member is connected to the splitter, and includes a transmission antenna receiving the distributed signal from the splitter and transmitting the transmission wave to the ground surface, and a reception antenna receiving a reception wave reflected from the ground surface. The mixer is connected to the distributor and the reception antenna, and mixes the distributed signal received from the distributor and the reception wave received from the reception antenna. The raw data generator is connected to the mixer, receives the mixed signal from the mixer, measures a distance for each pixel on the ground surface, and generates raw data corresponding to the received signal for each pixel. The shaking motion correction unit is connected to the raw data generation unit, and generates a plurality of partition raw data by dividing the raw data according to a preset spatial reference value. The preliminary reverse projection unit calculates a plurality of pre-correction reverse projection functions by performing a matching filter process for each segment raw data. The preliminary image restoration unit projects the pre-correction reverse projection functions for each pixel to generate a partition preliminary image for each of the divided composite openings. The distance direction rotation component detector sets an angle in which the distance direction component of each of the segment preliminary images is inclined from an ideal distance direction as the distance direction rotation angle of the corresponding segment preliminary image. The azimuth direction rotation component detection unit sets an angle in which the azimuth direction component of each segment preliminary image is inclined from an ideal azimuth direction as an azimuth direction rotation angle of the corresponding segment preliminary image. The correction data generator corrects the positions of each of the pixels using the distance direction rotation angle and the azimuth rotation angle for each division preliminary image, and matches each division preliminary image according to the corrected position of each pixel. A filtering process is performed to generate the corrected reverse projection function for each pixel as corrected segment data. In one embodiment, the pre-correction data generator may further generate a corrected image on the composite opening surface by projecting the corrected segment data for each corrected pixel.

In one embodiment, the preliminary reverse projection unit is in the raw data (S _IF,r (ω, _u'Mp ); ω is the frequency, _u'Mp is the position of the receiving antenna)), [Equation 1], and [Equation 2] By performing the matched filter process of, the pre-correction reverse projection function f(x' _i , _y'j ) for each pixel (x' _i , _y'j ) for each segment raw data can be calculated.

[Equation 1]

[Equation 2]

(In [Equation 1] and [Equation 2], K denotes the number of segmented raw data divided by 1/M by the shaking _{motion compensation unit} , and _u'Mp denotes the position of the receiving antenna at the time the p-th received wave is received. And t _dij represents the delay time of the i,j-th pixel, (x' _i ,y' _j ) represents the position (coordinate) of the i,j-th pixel on the raw data, and Wp is the signal measured by the receiving antenna denotes a window function of the intensity, t denotes a sampling time, ω denotes the frequency, u _'Mp denotes the location of the receiving antenna mounted on the aircraft in each block of raw _{data, S IF, r (ω,} u _'Mp) is the receive antenna u' the delay time of the received signal represents the raw data for a, t _dij (u _'Mp) is located (u of the receive antennas mounted on the aircraft' _Mp) of the case which is located _Mp Indicate)

In one embodiment, the correction data generation unit performs a matching filter process of [Equation 3] to [Equation 6] on the raw data (S _IF,r (ω, _u'Mp )) to each corrected pixel (x _i ,y _j ) inverse projection function f(x _i ,y _j ) is generated as corrected segment data, and the corrected segment data is projected for each of the corrected pixels (x _i ,y _j ), The corrected image may be generated.

[Equation 3]

_u'Mp =u _Mp -R _g tanφ _yaw

[Equation 4]

[Equation 5]

[Equation 6]

(In [Equation 3] to [Equation 6], u _Mp (u _x , u _y , u _z ) represents the coordinates corrected for the position of the reception antenna at the time point at which the p-th received wave is received, and u _Mp (u' _{x, u 'y, u'} z) represents the coordinates p-th received wave does not correct the position of the receiving antenna at the point to be received, R _g indicates the length of the received wave projected onto the ground surface, (x _c, y _c ) represents the coordinates of the reference point on the ground surface, (x _i ,y _j ) represents the coordinates of the corrected i,jth pixel, and f(x _i ,y _j ) represents the corrected i,jth reverse projection Represents a function)

In one embodiment, the correction data generation unit is to restore the i, j-th coordinates in the FMCW-SAR (Frequency Modulated Continuous Wave-Synthetic Aperture Radar) image by repeatedly calculating [Equation 3] to [Equation 6] through numerical analysis. I can.

In one embodiment, the distance direction rotation component detection unit may set the horizontal direction of each of the section preliminary images as a distance direction, and set an angle in which the distance direction component is inclined from the horizontal direction as the distance direction rotation angle (φ _rg ). have.

In one embodiment, the azimuth direction rotation component detection unit may set a vertical direction of each of the section preliminary images as an azimuth direction, and an angle in which the azimuth direction component is inclined from the vertical direction as the azimuth direction rotation angle (φ _yaw ). have.

In one embodiment, the raw data may include Frequency Modulated Continuous Wave-Synthetic Aperture Rader (FMCW-SAR) data measured by an aircraft.

In the segmented image restoration method using the aircraft-based segmented image restoration apparatus according to an embodiment of the present invention, the aircraft-based segmented image restoration apparatus receives a transmission antenna that transmits a transmission wave to a ground surface and a reception wave reflected from the ground surface. An antenna member including a receiving antenna; and a source data generator configured to generate source data corresponding to the received signal for each pixel by receiving the received wave and measuring a distance for each pixel on the ground surface; and A shaking motion correction unit that is authorized to generate a plurality of segment raw data, a reverse projection unit that calculates a reverse projection function for each pixel for each segment raw data by performing a matching filter process, and the reverse projection function for each of the original data. An image restoration unit that projects each pixel to generate an image on the composite aperture, and sets the angle of inclination of the inclination of the propagation inphase line in contact with the ground surface of the received wave for each segment raw data as a distance direction rotation angle. A distance direction rotational component detection unit, an azimuth direction rotational component detection unit for setting an inclined angle of a projection line vertically projecting the received wave onto the ground surface for each of the divisional raw data as an azimuth rotational angle, and the respective divisional raw data Each pixel includes a correction data generator for correcting the position of each pixel using the distance direction rotation angle and the azimuth direction rotation angle. In the split image restoration method, first, the transmission wave is transmitted onto the ground surface using the transmission antenna, and the reception wave reflected from the ground surface is received through the reception antenna. Subsequently, the distance of each pixel between the receiving antenna and the ground surface is measured using the received wave to generate raw data corresponding to the received signal for each pixel. Thereafter, the original data are divided according to a preset spatial reference value using the shaking motion correction unit to generate the divided raw data. Subsequently, a matching filter process is performed on each of the segment raw data using the reverse projection unit and the image restoration unit to generate segment preliminary images. Subsequently, the respective segment preliminary images are applied to the distance direction rotation component detection unit to set the distance direction rotation angle for each segment preliminary image. Thereafter, each of the segment preliminary images is applied to the azimuth direction rotation component detection unit to set an azimuth direction rotation angle for each segment preliminary image. Subsequently, the distance direction rotation angle and the azimuth direction rotation angle are applied to the correction data generator for each of the divided raw data to correct the positions of the pixels for each of the divided raw data. Subsequently, a matching filter process is performed according to the position of each corrected pixel for each of the divided raw data, and each of the divided data on which the matching filter process is performed for each of the divided raw data is projected for each of the corrected pixels, Generates a corrected image on a spherical surface.

In one embodiment, the step of generating the segment preliminary images by performing a matching filter process on each segment raw data comprises: the original data (S _IF,r (ω, _u'Mp ); ω is a frequency, _u'Mp is The matching filter process of [Equation 1] and [Equation 2] is performed on the position of the receiving antenna)), and the inverse projection function f(x' before correction for each pixel (x' _i ,y' _j ) for each segment raw data is performed. _i ,y' _j ) can be calculated.

[Equation 1]

[Equation 2]

(In [Equation 1] and [Equation 2], K denotes the number of segmented raw data divided by 1/M by the shaking _{motion compensation unit} , and _u'Mp denotes the position of the receiving antenna at the time the p-th received wave is received. And t _dij represents the delay time of the i,j-th pixel, (x' _i ,y' _j ) represents the position (coordinate) of the i,j-th pixel on the raw data, and Wp is the signal measured by the receiving antenna denotes a window function of the intensity, t denotes a sampling time, ω denotes the frequency, u _'Mp denotes the location of the receiving antenna mounted on the aircraft in each block of raw _{data, S IF, r (ω,} u _'Mp) is the receive antenna u' the delay time of the received signal represents the raw data for a, t _dij (u _'Mp) is located (u of the receive antennas mounted on the aircraft' _Mp) of the case which is located _Mp Indicate)

In an embodiment, the step of correcting the position of each pixel for each segment raw data includes matching filters of [Equation 3] to [Equation 6] in the raw data (S _IF,r (ω, _u'Mp )) By performing a process, the reverse projection function f(x _i ,y _j ) for each corrected pixel (x _i ,y _j ) is generated as corrected segment data, and the corrected segment data is converted into the corrected segment data (x _i , The corrected image on the composite opening surface may be generated by projecting for each y _j ).

[Equation 3]

_u'Mp =u _Mp -R _g tanφ _yaw

[Equation 4]

[Equation 5]

[Equation 6]

(In [Equation 3] to [Equation 6], u _Mp (u _x , u _y , u _z ) represents the coordinates corrected for the position of the reception antenna at the time point at which the p-th received wave is received, and u _Mp (u' _{x, u 'y, u'} z) represents the coordinates p-th received wave does not correct the position of the receiving antenna at the point to be received, R _g indicates the length of the received wave projected onto the ground surface, (x _c, y _c ) represents the coordinates of the reference point on the ground surface, (x _i ,y _j ) represents the coordinates of the corrected i,jth pixel, and f(x _i ,y _j ) represents the corrected i,jth reverse projection Represents a function)

According to the present invention as described above, in the aircraft-based segmented image restoration apparatus, even if the irradiation direction of the radar is distorted and a directing angle error occurs, or an error due to aircraft fluctuation occurs, a corrected reverse projection image can be obtained without additional physical measures. I can.

Since it is virtually impossible to remove the orientation angle error or the error due to the aircraft fluctuation through cross-validation due to the characteristic that the propagation phase plane propagates in a twisted state to the ground surface, conventionally, if errors due to the orientation angle error and/or aircraft fluctuation are found. Data was discarded without being reusable. Therefore, in the past, if an error due to orientation angle error or aircraft fluctuation is found in the reverse-projected image, it is necessary to adjust the direction of the transmission antenna and then depart the aircraft again to obtain new data. And cost. However, according to the exemplary embodiment of the present invention, since it is possible to obtain a back-projection image in which an error due to an orientation angle error and/or an error due to aircraft oscillation is eliminated by using the data obtained in one operation, time and cost are reduced.

Errors caused by aircraft fluctuations basically have the same aspect as the orientation angle error when differentiating aircraft operation. That is, the error caused by the aircraft oscillation caused by tilting the antenna member during the inclining process of the aircraft and the directing angle error caused by tilting the antenna member itself show the same result in terms of raw data. However, the orientation angle error is inclined at the same angle throughout the flight of the aircraft, but the only difference is that the error due to aircraft fluctuation changes with time.

In the present invention, by dividing the raw data obtained in the course of aircraft operation and dividing it into a kind of derivative, errors due to aircraft fluctuations are treated in the same manner as the orientation angle error.

In addition, by performing the preliminary matching filter process and the correction matching filter process together using one integrated reverse projection unit, the structure of the aircraft-based segmented image restoration apparatus is simplified and cost is reduced.

1 is a block diagram showing an aircraft-based split image restoration apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a process in which a squint error occurs in frequency modulated continuous wave-synthetic aperture radar (FMCW-SAR) data measured by an aircraft according to an embodiment of the present invention in a geometric structure.
3 is a reverse projection (BPA) image showing ideal data obtained when there is no orientation angle error in an aircraft according to an embodiment of the present invention in a distance direction and an azimuth direction.
FIG. 4 is an image obtained by projecting raw data obtained when a 45 degree orientation angle error exists in the aircraft shown in FIG. 2 in a distance direction and an azimuth direction.
FIG. 5 is a reverse projection (BPA) image showing data obtained when there is a 45-degree orientation angle error in the aircraft shown in FIG. 2 in the distance direction and the azimuth direction.
6 is a geometric image showing an azimuth angle when there is an orientation angle error in the segmented image restoration apparatus shown in FIG. 1.
FIG. 7 is a geometry image showing a radiation pattern in the azimuth direction of a transmission wave when there is an orientation angle error in the divided image restoration apparatus of the geometry shown in FIG. 6.
8 to 11 are geometric images showing a method of obtaining a distance direction rotation component φ _rg according to an embodiment of the present invention.
12 is a flowchart illustrating a method of restoring a segmented image using the aircraft-based segmented image restoration device shown in FIG. 1.
13 is a block diagram showing an aircraft-based split image restoration apparatus according to another embodiment of the present invention.
14 is a flow chart showing a split image restoration method using the aircraft-based split image restoration apparatus shown in FIG. 13.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. In the present invention, various modifications may be made and various forms may be applied, and specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form disclosed, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing each drawing, similar reference numerals have been used for similar elements. In the accompanying drawings, the dimensions of the structures are shown to be enlarged compared to the actual size for clarity of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of being added.

In addition, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

1 is a block diagram showing an aircraft-based image restoration apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the aircraft-based split image restoration apparatus includes an antenna member 110 and 120, a waveform generator 150, a distributor 160, a mixer 205, a raw data generator 210, and a vibration correction unit 290. ), preliminary reverse projection unit 220, preliminary image restoration unit 230, error determination unit 240, distance direction rotation component detection unit 250, orientation direction rotation component detection unit 260, correction data generation unit 270, And a corrected image restoration unit 280.

The waveform generator 150 generates a signal having the same waveform as the transmission wave 2. The waveform generator 150 may generate various signals such as a triangular wave, a sawtooth wave, and the like. For example, a sawtooth wave refers to a waveform in which the frequency increases constantly over time, and then the frequency is initialized every predetermined period and then increases constantly. Since the sawtooth wave can directly measure the Doppler frequency according to the distance, it can provide velocity information according to the distance.

The splitter 160 is connected to the waveform generator 150, the transmission antenna 110 of the antenna members 110 and 120, and a mixer 205. The divider 160 receives the signal generated from the waveform generator 150 and distributes it to the transmission antenna 110 and the mixer 205.

The antenna members 110 and 120 transmit the transmission wave 2 of the signal applied from the distributor 160 and receive the reception wave 4 reflected from the ground surface. In this embodiment, the antenna members 110 and 120 include a transmission antenna 110 for transmitting the transmission wave 2 and a reception antenna 120 for receiving the reception wave 4.

The mixer 205 mixes the signal received through the distributor 160 and the received wave 4 applied from the reception antenna 120 and transmits the mixture to the raw data generator 210.

FIG. 2 is a diagram showing a state in which a Squint Angle exists in Frequency Modulated Continuous Wave-Synthetic Aperture Radar (FMCW-SAR) data measured by an aircraft according to an embodiment of the present invention, as a geometry. In Fig. 2, the y-axis is the traveling direction of the aircraft, the x-axis is a direction perpendicular to the traveling direction of the aircraft on a plane, the z-axis is a direction from the ground to the aircraft, and f(x _c , y _c ) is a reflection of the electromagnetic waves of the radar on the surface. It represents an irradiation reference point where an object exists, and an arbitrary irradiation point f(x ₀ , y ₀ ) located on the same line in the y-axis direction as the irradiation reference point. In the present embodiment, the directing angle of FIG. 2 is a case where a directing angle error exists because the antenna members 110 and 120 themselves are twisted, or when a disturbance occurs in the directing direction of the antenna members 110 and 120 due to aircraft fluctuation. Can be caused by

2, the actual coordinates of the aircraft _{(u 'x, u' y} , u 'z) and, oriented ideal coordinates to be the position of aircraft in the absence of each error (u _x, u _y, u _z )to be. The split image restoration apparatus according to an embodiment of the present invention moves in the u direction while being loaded on an aircraft. The survey reference point f(x _c , y _c ) to be investigated is located on the surface (z _c = 0).

1 and 2, the raw data generation unit 210 measures the distance between the reception antenna 120 and the irradiation reference point f(x _c , y _c ) on the ground surface from a signal received from the mixer 205 Raw data representing the location of the survey reference point f(x _c , y _c ) are generated. The raw data may be FMCW-SAR (Frequency Modulated Continuous Wave-Synthetic Aperture Radar) data measured by the aircraft.

In order to generate raw data in the FMCW-SAR format, the raw data generator 210 first generates raw data by applying a signal received from the mixer 205 to the following [Equations 1] to [Equations 4]. In [Equation 1] to [Equation 4], i, j represents the position of each pixel of the reconstructed image obtained as a 2D preliminary image (x' _i , _y'j ), t is the sampling time, f ₀ is the center frequency , K _r is the modulation rate, u'is the antenna position, τ is the target delay time, IF is the intermediate frequency, and c is the speed of light. In this embodiment, since the reconstructed image is in a two-dimensional form, it is represented by two variables (i, j), and since the antenna position is a three-dimensional form according to the movement of the aircraft, three variables (u' _px , _u'py , _u'pz ).

Referring to [Equation 1] to [Equation 4], the raw data generation unit 210 receives the reference transmission signal and the reception wave 4 distributed from the mixer 205 and directly performs frequency down conversion. , A beat frequency component corresponding to the difference between the two signals is received and sampled to generate raw data.

[Equation 1]

In [Equation 1], S _t (t) is a transmission signal and becomes a reference signal to be used as a matched filter during the process of generating a bit frequency and processing a radar signal. In this embodiment, a delayed de-chirp is used to effectively process an intermediate frequency (IF) received signal by delaying a reference signal using a delay line d.

[Equation 2]

In [Equation 2], S _r (t) represents a received signal to which the target delay time (τ _n ) is applied in [Equation 1].

[Equation 3]

In [Equation 3], S _IF and _r (t,u') represent raw data as a received signal of an intermediate frequency (IF). The intermediate frequency (IF) is obtained by down-converting the transmission and reception signals.

[Equation 4]

In [Equation 4], τ _n (u') is the relative distance between the irradiation reference point (x _n , y _n , z _n ) and the position (u') of the antenna members 110 and 120 as the delay time of the n-th target It is represented by In [Equation 4], the irradiation reference point (x _n , y _n , z _n ) is expressed in a three-dimensional coordinate system, but if the irradiation reference point is located on the ground surface, the z component may be omitted for convenience.

In [Equation 1] to [Equation 4], the signal strength component is omitted for convenience. For those with ordinary knowledge and experience in the art, although not considered in [Equation 1] to [Equation 4], signal strength components, antenna beam patterns, target distance attenuation, reflectivity, etc. may be additionally considered. You will be able to understand.

The shaking motion correction unit 290 is connected to the raw data generation unit 210, divides the raw data according to a preset spatial reference value M, and sets the divided raw data as partition raw data. In this embodiment, the shaking motion correction unit 290 divides the raw data into 1/4 to 1/8 size. The shaking motion correction unit 290 may generate M divided raw data by uniformly dividing the raw data, and in another embodiment, only raw data of a limited size (sub-aperture) among the raw data are consecutive. It can also be extracted and used as segmented raw data.

For example, when the length of the composite opening is 500 m, the shaking motion correction unit 290 may generate segmented raw data having a length of 100 m by dividing the spatial reference value M by 1/5.

The first reason for converting raw data into segmented raw data is to perform a kind of differentiation on the raw data according to the flight path of the aircraft to process errors caused by aircraft fluctuations together with the orientation angle errors.

The second reason for setting the divided raw data is that the importance of the data adjacent to the survey control point is the highest among the raw data by the received wave (4) in restoring the image, and the importance of the data is lower as the distance from the survey control point increases. . In the conventional matched filter process, iterative calculation is performed on the entire data, which, apart from the fact that the calculation process becomes complicated, the reliability of the reconstructed image is degraded because errors caused by aircraft fluctuations are included in the calculation process as they are.

3 is a conceptual diagram showing a reverse projection image of a transmission wave and an irradiation reference point according to the movement of the aircraft when there is no error due to an orientation angle error or an aircraft oscillation in the aircraft according to an embodiment of the present invention. This is a reverse projection (BPA) image showing ideal raw data obtained in the case where there is no error due to a direction angle error or an error due to aircraft oscillation in the aircraft according to an embodiment of the present invention. In FIG. 4, the size of one pixel in the azimuth direction and the distance direction is 0.2m.

1, 3, and 4, when there is no error due to an orientation angle error or aircraft oscillation, a transmission wave 2 is transmitted from the transmission antenna 110 to the irradiation reference point f(x _c , y _c ). . If there is no error due to the orientation angle error or the aircraft fluctuation, the transmission wave 2 travels in a direction perpendicular to the travel direction of the aircraft.

The transmission wave 2 radiated by the transmission antenna 110 is reflected at the irradiation reference point f(x _c , y _c ) to become a reception wave 4 and is received by the reception antenna 120. The position of the aircraft, the farther from the irradiation reference point f (x _c, y _c) weakens the strength of the reflected wave of the irradiated reference point _{f (x c, y c)} .

Becomes the strength of the reflected waves gradually stronger as the aircraft moves in the u _c points from the u _'c point, the strength of the reflected wave maximum at the point in time at which the SAR radar aircraft exactly passes through the irradiation reference point f (x _c, y _c) Show. That is, when there is no directing angle error, the strongest reflected wave 4 is received when the aircraft passes the irradiation reference point f (x _c , y _c ) and the point (u _c ) located in a row in the x-axis direction.

Therefore, when the reflected wave data of the SAR radar, which does not have an error due to a directing angle error or an error due to aircraft oscillation, are projected back according to the direction of azimuth and distance (BPA), it shows a cross shape where the vertical line and the horizontal line cross each other.

5 is a conceptual diagram showing a reverse projection image of a transmission wave and an irradiation reference point according to the movement of the aircraft when there is only an orientation angle error in the aircraft according to an embodiment of the present invention, and FIG. 6 is a 45 degree view in the aircraft shown in FIG. It is an image of projecting raw data obtained when only the orientation angle error exists in the distance direction and the azimuth direction, and FIG. 7 shows the data obtained when only the orientation angle error of 45 degrees exists in the aircraft shown in FIG. 1 in the distance direction and the azimuth direction. This is the reverse projection (BPA) image shown. In Fig. 7, the size of one pixel in the azimuth direction and the distance direction is 0.2m.

Referring to FIG. 6, if the raw data S _IF , _r (t, u') are projected in the distance direction and the azimuth direction as they are, they are displayed in an inclined straight line shape. Although not shown, if a person with ordinary knowledge and experience in the art projects the raw data without orientation angle error as it is, it can be seen that it is displayed in a straight line in the vertical direction. will be.

Referring to FIGS. 1, 5, and 7, the error determination unit 240 includes an orientation angle error and/or when two lines intersect in an inclined state based on the investigation reference point f(x _c , y _c ). Alternatively, it is determined that there is an error due to aircraft fluctuations (Fig. 7).

8 is a conceptual diagram showing a reverse projection image of a transmission wave and an irradiation reference point according to the movement of the aircraft when an error due to an orientation angle error and an aircraft oscillation exist in the aircraft according to an embodiment of the present invention, and FIG. This is a full-aperture image obtained by performing reverse-projection (BPA) of all the segment raw data obtained in the case where an error due to an orientation angle error and an error due to aircraft oscillation exist in the aircraft shown in FIG.

Referring to FIGS. 8 and 9, a divisional operation method using the shaking motion correction unit 290 is used, but each segment raw data is transmitted to the preliminary reverse projection unit 220, and the matching filter process is not performed. When the data is transmitted to the preliminary reverse projection unit 220 as it is to perform a matching filter process, the preliminary reverse projection unit 220 performs the i, j-th pixel (coordinates (x' _i ,y' _j ) in the FMCW-SAR preliminary image. )), the matched filter process of [Equation 15] and [Equation 16] is performed.

In [Equation 15] and [Equation 16], M denotes the ratio at which the raw data of the segment generated by the shaking motion correction unit 290 is reduced compared to the original data, and _u'Mp is the p-th transmission wave from the raw data of the M-th segment. _Denotes the reference antenna position of, t _dij denotes the delay time of the i,j-th pixel, and (x' _i ,y' _j ) denotes the position (coordinate) of the pixel on the raw data.

[Equation 15]

[Equation 16]

In [Equation 15], Wp represents the window function for the signal strength measured by the receiving antenna 120, t represents the sampling time, ω represents the frequency, and S _IF,r (ω, _u'Mp ) is _Represents the phase component (or raw data) of the received signal when the receiving antenna 120 is located at _u'Mp .

In [Equation 16], t _dij (u' _Mp ) represents the delay time according to the position (u' _Mp ) of the reception antenna 120 mounted on the aircraft.

[Expression 15], and reference to [expression 16], Reserve projection unit 220 'in the _(Mp, the received signal (S _{IF, r} (ω, u each point u) "to the aircraft movement _Mp)) and a matched filter ^{_{(S * M (t dij (}} u '(i, y Mp))) x coordinates by summing the product of the'_'j) of i, j-th pixel of the preliminary image f (x a' _i, y It is obtained by the inverse projection function of ' _j ).

In the case of performing the matched filter process by using the divisional operation technique, but not performing the matched filter process for each subdivision raw data, and performing the matched filter process by transmitting all subdivision raw data as it is to the preliminary reverse projection unit 220, the entire composite opening ( The same result as the case of backprojecting the raw data of full-aperture appears. Therefore, as shown in FIG. 9, the reverse projection image appears in a distorted form.

FIG. 10 is a diagram illustrating a matching filter process by dividing raw data into four and using a divisional operation technique by dividing raw data into four, and setting partition raw data to perform a matching filter process when there is no orientation angle error and only an error due to aircraft fluctuations. Fig. 11 shows the reverse projection image of the case, and FIG. 11 is a case where only an error due to aircraft oscillation without an orientation angle error exists, according to an embodiment of the present invention, the raw data is divided into 8 to use a division operation technique, and the division raw data is It shows the reverse projection image when setting and performing the matched filter process.

In an embodiment of the present invention, the preliminary reverse projection unit 220 performs a matching filter process for each segment raw data with reference to [Equation 17] and [Equation 18] (1 <K <M).

In [Equation 17] and [Equation 18], K represents the number of the segment raw data divided by 1/M by the shaking motion correction unit 290, and _u'Kp is the reference of the p-th transmission wave in the K-th raw data _{Represents the} antenna position, t _dij represents the delay time of the i,j-th pixel, and (x' _i ,y' _j ) represents the position (coordinate) of the pixel on the raw data.

[Equation 17]

[Equation 18]

In [Equation 17], Wp represents the window function for the signal strength measured by the receiving antenna 120, t represents the sampling time, ω represents the frequency, and S _IF,r (ω, _u'Kp ) is _Represents the phase component (or raw data) of the received signal when the receiving antenna 120 is located at _u'Kp .

In [Equation 18], t _dij (u' _Mp ) represents the delay time according to the position (u' _Mp ) of the reception antenna 120 mounted on the aircraft.

1, [Equation 17], and [Equation 18], the preliminary reverse projection unit 220 at each point (u' _Kp ) the aircraft moves, the received signal (S _{IF, r} (ω, _u'Kp) )) and the matching filter (S ^* _M (t _dij (u' _Kp ))) are summed and the preliminary image of the i,j-th pixel with the coordinates (x' _i ,y' _j ) is f(x' _It is found by the reverse projection function of _i ,y' _j ).

In an exemplary embodiment of the present invention, the preliminary reverse projection unit 220 uses a divisional operation technique and performs a matching filter process on each of the divided raw data.

Referring to the reverse-projection image of the matched filter process using the segmented raw data generated by dividing the raw data corresponding to the composite opening surface into four as shown in FIG. 10, it is possible to restore an image from which an error caused by aircraft fluctuation has been removed.

Referring to the reverse-projection image of the matched filter process using the segmented raw data generated by dividing the raw data corresponding to the composite opening surface as shown in FIG. 11, the aircraft fluctuation is removed, but the azimuth resolution is lowered, resulting in a decrease in image accuracy. .

If the number M in which the original data is divided is too small, errors due to the motion of the aircraft are not eliminated, and if the number M in which the original data is divided is too large, the azimuth resolution is lowered and the accuracy of the image is degraded. In this embodiment, the number M in which the original data is partitioned may be 4 to 6. Preferably, the number M in which the raw data is partitioned may be 5.

Since the raw data corresponds to the composite opening surface, when the number (M) where the raw data is divided increases, the interval between which the composite opening surface is divided decreases, and when the number (M) where the raw data is divided decreases, the composite opening surface is divided. The gap becomes wider. If the distance between which the composite opening is divided is too narrow, the azimuth direction resolution is lowered and the accuracy of the image is deteriorated.

For example, the raw data may be partitioned at intervals of 20 m to 50 m based on the composite opening surface. When the interval at which the composite opening is partitioned is less than 20m, the azimuth resolution of the reconstructed image is degraded. If the distance between which the composite opening is divided is greater than 50m, the error due to aircraft oscillation is not eliminated.

In this embodiment, the preliminary back-projection 220 is repeatedly performed on the pixels of each composite aperture divided into M pieces. The divided composite opening is a synthesis of the raw data measured on the path of the aircraft, and the width of the composite opening is the width that can be detected by the beam of the FMCW radar. The length of is corresponding to the length of the aircraft's travel distance divided into M pieces. The input signal represents segment raw data (or radar received signal, etc.) and can be expressed as S _IF,r (ω, _u'Mp ).

Preliminary image restoring unit 230 to restore the reserve projection 220 of each pixel by back-projection function f (x _'i, y' _j) dividing the preliminary image for each of the compartments synthesis opening surface obtained by, one M One preliminary image is generated by combining the partition preliminary images for each divided area.

One composite opening corresponds to the M compartment composite openings divided according to the track the aircraft moves during a certain operating time.

The error determination unit 240 analyzes the preliminary image and determines whether or not there is an error due to an orientation angle error and/or an aircraft motion. Hereinafter, a method of determining an error due to an orientation angle error and/or an aircraft oscillation in one compartment preliminary image is described, but if a person with ordinary knowledge and experience in the art, the orientation angle error and /Or you may find that you can judge the error caused by the aircraft fluctuation.

1, 3, and 4, the error determination unit 240 determines a point where the intensity of the reflected wave 4 is high in each segment preliminary image reconstructed by the preliminary image restoration unit 230 as a reference point f ( When x _c , y _c ) is set and the vertical line and the horizontal line intersect based on the irradiation reference point f (x _c , y _c ), it is determined that there is no error due to an orientation angle error or aircraft oscillation (Fig. 4).

1, 5, and 7, the error determination unit 240 has a directing angle error when two lines intersect in an inclined state based on the investigation reference point f(x _c , y _c ). It is determined to be done (Fig. 7).

1, 8, and 9, the preliminary reverse projection unit 220 performs a matching filter process for each of the divided raw data according to [Equation 17] and [Equation 18]. In comparison, when the image is not constant and an image where several lines intersect, it is determined that there is an error due to aircraft shaking (FIG. 9). In another embodiment, the preliminary reverse projection unit 220 transmits the entire segment raw data as it is to the preliminary reverse projection unit 220 according to [Equation 15] and [Equation 16] to further perform a matching filter process to prevent aircraft oscillation. It can also be determined whether there is an error due to.

In an embodiment of the present invention, when the movement trajectory of the aircraft is differentiated, that is, when the composite opening surface is divided according to the traveling direction of the aircraft, an error due to aircraft fluctuation is taken as a directing angle error. In other words, without the need to distinguish between the directing angle error of the transmitting antenna 110 and the error caused by aircraft oscillation, the directivity angle from which the transmitted wave 2 is transmitted can be obtained by analyzing the straight lines of each segment preliminary image. It is possible to correct errors.

Referring again to FIG. 2, when the antenna members 110 and 120 of the split image restoration apparatus are inclined by the orientation angle (φ _sq ), the survey reference point is not the time when the aircraft passes the irradiation reference point f(x _c , y _c ). The strongest reflected wave is received at the irradiation point f(x ₀ , y ₀ ) that is less than f(x _c , y _c ) and the point located in a row in the x-axis direction. That is, the strongest reflected wave 4 is received when the antenna members 110 and 120 of the divided image restoration apparatus are inclined by the irradiation reference point f(x _c , y _c ) and the directivity angle (φ _sq ).

In simple geometric terms, the orientation angle (φ _sq ) is the inclination (θ _inc ) projecting the position of the aircraft in the vertical direction, and the azimuth rotation from the point on the projected surface to the irradiation reference point f(x _c , y _c ). It seems that it can be obtained using the angle (φ _yaw ).

However, if an orientation angle error appears in the antenna members 110 and 120 of the segmented image restoration device, the radio wave motion phase surface of the transmission wave 2 irradiated from the corresponding transmission antenna 110 is not in a direction perpendicular to the ground surface. It is not possible to obtain the orientation angle (φ _sq ) simply by projecting the position of φ to the ground surface.

12 is a graph showing a distance direction rotation angle (φ _rg ) and an azimuth direction rotation angle (φ _yaw ) in the section preliminary image shown in FIG. 10.

2 and 12, since the propagation in-phase plane (5 in FIG. *) is not in a direction perpendicular to the ground surface, when the received wave 4 data obtained through the receiving antenna 120 is processed and back-projected, the actual An intersection is formed as if there is an irradiation reference point at a point preceding the location, and the shape of the intersection is also distorted.

When the error determination unit 240 according to the embodiment of the present invention determines that there is an error due to an orientation angle error and/or aircraft oscillation, the distance direction rotation component detection unit 250 and the azimuth direction rotation component detection unit 260 are used. Therefore, by taking into account the radio wave motion phase plane (5 in Fig. *), the distance direction rotation angle (φ _rg ) and the azimuth direction rotation angle (φ _yaw ) are obtained, and by using this, due to the error due to the orientation angle error and/or the aircraft oscillation. Correct the error that occurs.

When there is an error due to a directivity angle error and/or aircraft oscillation, the image appears distorted because the radio wave motion phase plane is tilted. Specifically, if the section preliminary image obtained by the preliminary image restoration unit 230 is projected on a graph in the distance direction (horizontal direction on the graph) and the azimuth direction (vertical direction on the graph), the distance direction component of the section preliminary image is ideal. It is inclined by the distance direction rotation angle (φ _rg ) from the distance direction (horizontal direction on the graph), and the azimuth direction component of the segment preliminary image is inclined by the azimuth rotation angle (φ _yaw ) from the ideal direction (vertical direction on the graph). It is displayed as a status.

The distance direction rotation component detection unit 250 optically analyzes each segment preliminary image obtained by the preliminary image restoration unit 230, and the distance direction component of each segment preliminary image is inclined from the ideal distance direction (horizontal direction on the graph). Is set as the distance direction rotation angle (φ _rg ) of the corresponding section preliminary image.

The azimuth direction rotation component detection unit 260 optically analyzes each preliminary image obtained by the preliminary image restoration unit 230 to determine the angle in which the azimuth direction component of the subdivision preliminary image is inclined from the ideal azimuth direction (vertical direction on the graph). Set the azimuth rotation angle (φ _yaw ) of the preliminary section.

Although it is not intended to limit the scope of the present invention by theory, a process in which an error due to an orientation angle error and/or an aircraft oscillation is projected onto the compartmental preliminary image obtained by the preliminary reverse projection unit 220 and the preliminary image restoration unit 230 Is described using the drawings and equations as follows.

Errors caused by aircraft fluctuations basically have the same aspect as the orientation angle error when differentiating aircraft operation. That is, the error caused by the aircraft oscillation caused by the antenna member 110 tilting during the inclining process of the aircraft and the directing angle error caused by tilting the antenna member 110 itself show the same result in terms of raw data. However, the orientation angle error is inclined at the same angle throughout the flight of the aircraft, but the only difference is that the error due to aircraft fluctuation changes with time.

In the present invention, by dividing the raw data obtained in the course of aircraft operation and dividing it into a kind of derivative, errors due to aircraft fluctuations are treated in the same manner as the orientation angle error.

FIG. 13 is a geometric image showing an azimuth angle when there is an error due to an orientation angle error and/or an aircraft oscillation in the divided image restoration apparatus shown in FIG. 1.

1 and 13, the azimuth rotation angle (φ _yaw ) in the error due to the orientation angle error and/or the aircraft oscillation is between the antenna members 110 and 120 and the irradiation reference point f(x _c , y _c ). Distance R, the height H ₀ from the ground to the antenna members 110, 120, the horizontal distance R _g from the point where the antenna members 110, 120 are projected onto the ground to the irradiation reference point f(x _c , y _c ), the antenna The distance R ₀ between the irradiation points f(x ₀ , y ₀ ) by extending from the position of the members 110 and 120 toward the ground in a direction perpendicular to the direction of the aircraft travel, by the orientation angle (φ _sq ) [Equation 5] and It can be represented by [Equation 6].

[Equation 5]

[Equation 6]

14 is a geometric structure image showing a radiation pattern in the azimuth direction of a transmission wave when there is an error due to an orientation angle error and/or an aircraft oscillation in the segmented image restoration apparatus of the geometric structure shown in FIG. 13.

1, 13, and 14, when there is an error due to an orientation angle error and/or an aircraft oscillation in the divided image restoration apparatus, the magnitude function (An) characteristic of the intermediate frequency received signal of [Equation 3] If modeled mathematically, it can be expressed as [Equation 7].

[Equation 7]

In [Equation 7], when there is an error due to an orientation angle error and/or aircraft oscillation in the segmented image restoration device, the magnitude function (An) of the intermediate frequency received signal is the radar cross-sectional area (σ) of the target located on the irradiation reference point It is proportional to and inversely proportional to the distance squared (I/R ² ), and can be expressed as a value obtained by applying the antenna radiation pattern ( sinc2( )φ _n θ _n ) and the correction constant (C). Here, when the reflectivity of the target located on the irradiation reference point and the correction constant are normalized, the relative size change of the size function depends on the distance and the radiation pattern. Therefore, if there is an error due to the orientation angle error and/or the motion of the aircraft in the segmented image restoration device, the antenna radiation pattern reflecting the change in the elevation angle (θ) and azimuth angle (φ) of the transmission wave (2) according to the target position in the geometry Model modification is required.

When there is an error due to the orientation angle error and/or the motion of the aircraft in the segmented image restoration device, the change in the elevation angle (θ) and the azimuth angle (φ) of the transmission wave (2) according to the position of the target located on the survey reference point in the geometry When reflecting, the elevation angle and the azimuth angle can be expressed as [Equation 8] and [Equation 9]. [Equation 8] and [Equation 9] are corrected for the angle of incidence (θ _inc ) and the angle of directivity (φ _sq ) so that the error due to the orientation angle error and/or the aircraft oscillation is reflected in the existing radiation pattern model.

[Equation 8]

[Equation 9]

50˚)을 갖도록 설계되어 거리에 대한 변화량에 둔감한 특성이 있다. 반면에 방위각 방향 안테나 방사패턴의 경우, 좁은 빔 폭(예,

10˚)의 적용과 거리에 따른 지향각도가 변화하는 특성이 있어서 [식 9]의 우변에서 두 번째 항(φ_sq(R), [식 10] 참조)과 [식 5]의 관계식을 통해 재정의하여 수정된 모델에 적용한다.In general, high-angle antenna radiation patterns have a wide beam width (e.g.,

It is designed to have 50˚) and is insensitive to the amount of change over distance. On the other hand, in the case of the azimuth direction antenna radiation pattern, a narrow beam width (e.g.,

10˚) is applied and the orientation angle varies depending on the distance, so the second term from the right side of [Equation 9] (Refer to φ _sq (R), [Equation 10]) and [Equation 5] Applied to the model modified by

[Equation 10]

15 to 18 are geometric images showing a method of obtaining a rotational component φ _rg in a distance direction according to an exemplary embodiment of the present invention.

In the present invention, the characteristic change due to the orientation angle error and/or the error caused by the aircraft motion of the segmented image restoration device is analyzed through image restoration using a reverse projection algorithm, and the composite opening is divided along the direction of the aircraft travel. Additional calculation techniques are applied.

When the original data of the segment with errors due to the orientation angle error and/or the aircraft oscillation are inserted into [Equation 17] and [Equation 18] and projected back, the degree of rotation is different from the orientation component. The reason is that the transmitted wave (2) is spatially inclined back to a predetermined angle by the antenna squint-angle in the slant-range, along the equi-phase plane. This is because the trail of the transmission wave 2 is projected along the tangent line (6 in Fig. 16) where the inclined in-phase surface and the ground surface contact each other. Specific details will be described in detail with reference to the accompanying drawings.

FIG. 15 is a diagram illustrating a beam angle (φ _sq ) in the case where there is an error due to a beam angle error and/or an aircraft oscillation. In FIG. 15, the directing angle (φ _sq ) is an angle obtained by adding the angle in which the antenna member is inclined due to a directing angle error and the angle in which the antenna is inclined by the aircraft oscillation.

Referring to FIG. 15, k _i represents the vector component in the direction in which the transmission wave (2') travels when there is no directivity angle (φ _sq = 0), and k _i,sq represents the vector component in which the directivity angle exists. In case (φ _sq > 0°), it represents the vector component of the direction in which the transmission wave 2 travels. Since the vector components (k _i , k _{i, sq} ) of the two transmission waves (2', 2) are located on the same plane, the two vector components (k _i , k _{i, sq} ) have a common vertical vector ( n) has a component. In other words, there is no change in characteristics of the vertical in-phase plane of the two transmission waves 2'and 2 based on the inclined propagation plane, and only the propagation direction of the transmission wave is moved by the orientation angle (φ _sq ).

16 is a geometric structure showing an in-phase plane according to an error due to an orientation angle error and/or an aircraft oscillation when the observation reference plane is the ground surface.

Referring to FIG. 16, when the observation reference plane according to the directivity angle φ _sq is the ground surface GR, the in-phase plane 5 in the vertical direction of the vector component k _{i,sq in the} traveling direction of the transmission wave 2 is Rather than being perpendicular to the ground surface (GR), it is inclined at a predetermined angle from a plane perpendicular to the ground surface (G0-u' _c (u _x ,u _y ,u _z )-f(x _c ,y _c )) It becomes the true plane (the plane connecting G _sq -u' _c (u _x ,u _y ,u _z )-f(x _c ,y _c )).

A plane inclined at a predetermined angle from a plane perpendicular to the ground surface (G0-u' _c (u _x ,u _y ,u _z )-f(x _c ,y _c )) (G _sq -u' _c The plane connecting (u _x ,u _y ,u _z )-f(x _c ,y _c )) becomes the in-phase plane (5) in the vertical direction of the transmission wave (2) according to the directivity angle, and is in contact with the ground surface (GR). Traces of the transmission wave 2 traveling in the distance direction along the radio wave in-phase line 6 are projected onto the ground surface 5.

In an embodiment of the present invention, the distance direction rotation component (φ _rg ) extracted by the distance direction rotation component detection unit 250 is a vertical direction of the transmission wave 2 including an error due to a direction angle error and/or an aircraft oscillation. It corresponds to the angle at the irradiation reference point f(x _c , y _c ), which becomes the intersection point between the in-phase surface 5 and the ground surface GR.

That is, the received wave 4 detected by the reflection of the transmitted wave 2 is not a projection line 6'connecting the vertical point G0 and the irradiation reference point f(x _c , y _c ) of the segmented image restoration device, but is inclined. The vibrational phase surface 5 propagates along the radio wave motion phase line 6 projected on the ground surface GR, and becomes a signal that detects an object on the radio wave motion phase line 6.

The distance direction rotation component φ _rg may be calculated using the location of the irradiation reference point f(x _c , y _c ) and coordinate information of the point B. The process of calculating the coordinate information of the point B will be described with reference to FIG. 10.

17 and 18 are geometric structures showing a process of calculating the coordinates of a point B on a tangent line projected on the ground surface from an arbitrary point A on a path along which the transmission wave 2 travels.

Referring to FIG. 17, a vector component (p) connecting an arbitrary point A on the path where the transmission wave 2 travels and a point B on the tangent line projected on the ground surface GR is the same as the vertical vector n. . In the embodiments of the present invention, the distance direction rotation angle (φ _rg ) is an ideal distance direction in which the propagation in-phase line 6 of the received wave 2 in contact with the ground surface GR does not have a directivity angle. It means the inclined angle from (φ _rg ). In addition, the orientation direction angle of rotation (φ _yaw) refers to the angle (φ _yaw) inclined from the receiving wave (2) the ground (GR) the ideal orientation direction does not have this orientation angles tuyoungseon (6 ') a vertical projection with a do.

When the position of the point A is determined, the coordinates of the intersection point B with the ground surface GR can be calculated using the vertical vector n. [Equation 11] and [Equation 12] are equations for storing the coordinate information of the point A (x _A , y _A , z _A ) located on the path where the transmission wave 2 travels. First determined as a point in the coordinate information of the _{y A (u 'y <y} A <y c) range (see Fig. 9). Transmission connecting the center of the composite opening surface (u' _c (u' _x ,u' _y ,u' _z )), which is the area on the plane where the radar image is obtained, and the center of the target on the irradiation control point (f(x _c , y _c )) The coordinate information of the point A on the wave (2) progress path (u' _c → f _c ) is calculated using a conditional expression such as [Equation 11].

[Equation 11]

[Equation 12]

[Equation 12] can obtain the x-coordinate component (x _A ) of the point A by solving three equations in which the size of the 3D vector component is 0 using the conditional expression of [Equation 11].

Referring to the first equation of [Equation 12], the x-coordinate component (x _A ) of the point A is the y-coordinate component (y _A ) of the point A, and the coordinates of the center of the composite opening surface (u' _x ,u' _y , u can be expressed by the _'z), and coordinates of the target on the irradiation reference point _{(x c, y c, z} c).

Referring to the second equation of [Equation 12], the z coordinate component (z _A ) of the point A is the x coordinate component (x _A ) and the coordinates of the center of the composite opening (u' _x ,u' _y ,u' _z) Can be represented by ).

Referring to FIG. 18, the coordinates of the point B from the coordinate information of the point A (x _A , y _A , z _A ) using the geometry (y=y _A ) on the xz plane where the component in the y-axis direction is y _A Information (x _B , y _B , z _B ) can be obtained. The coordinate information (x _B , y _B , z _B ) of the point _B can be calculated by obtaining the intersection of the extension line of the vertical vector (n) component and the ground surface from the coordinate information (x _A , y _A , z _A ) of the point A. Therefore, it is possible to calculate the coordinate information (x _B , y _B , z _B ) of the point B that changes according to the setting value of the incident angle (θ _inc ) of the transmission wave 2.

Of the coordinate information of point B (x _B , y _B , z _B ), the y-axis coordinate component (y _B ) and the z-axis coordinate component (z _B ) are from the coordinate information of point A (x _A , y _A , z _A ). Can be calculated. Of the coordinate information of the point B (x _B , y _B , z _B ), the x-axis coordinate component (x _B ) can be calculated through the geometry of FIG. 18 and [Equation 13].

[Equation 13]

On the other hand, the y-axis direction component (y _B ) of point _B is the same as the y-axis direction component (y _A ) of point A (y _B =x _B ), and point B is projected onto the ground surface (GR) (z _B = 0), so the coordinates of the point B can be expressed as (x _B , y _A , 0). When the coordinates of the irradiation reference point f(x _c , y _c ) are displayed in three dimensions, the coordinates of the target can be expressed as (x _c , y _c , 0).

If the coordinates of the point B (x _B , y _A , 0) and the coordinates of the target (x _c , y _c , 0) are applied to [Equation 14], the propagation path of the transmission wave (2) projected on the ground surface (GR) Distance direction rotation angle (φ _rg ) can be obtained.

[Equation 14]

In the present embodiment, by applying the distance direction rotation angle (φ _rg ) obtained by the distance direction rotation component detection unit 250 to [Equation 14], the coordinates of the point B (x _B , y _A , 0) and the coordinates of the target ( You can find the relationship between x _c , y _c , and 0).

Referring back to FIG. 2, [Equation 17] shows that the transmission wave (2) is from the point of u _Mp (u _x , u _y , u _z ) in the case of not taking into account the error due to the orientation angle error or the aircraft fluctuation. It proceeds to f(x _c , y _c )), and reverse projection is performed using the ideal segmented raw data.

However, oriented as shown in the embodiment of the present invention contain any error due to each error and / or aircraft oscillation, the transmission wave (2) is directed from the u _'Mp (u' _x, u _'y, u' _z) point In a state that is inclined by an angle (φ _sq ), it proceeds to the irradiation reference point (f(x _c , y _c )) to generate distorted segmented raw data.

If u _Mp (u _x , u _y , u _z ) is applied as it is to the position of the segmented image restoration apparatus in [Equation 17] for the distorted segmented raw data, a distorted reverse projection image is obtained. Therefore, when applied as a _{u Mp (u x, u y} , u z) to the position of the divided image decoding device in the expression 17] designed _{u 'Mp (u' x,} u 'y, u' z) correction after applying We need to find the u _Mp (u _x , u _y , u _z ).

_Mp u (u _x, u _y, u _z) and _{u Mp (u 'x, u} ' y, u 'z) corresponding to raw data blocks on the corrected geometry satisfies the formula (19).

[Equation 19]

_u'Mp =u _Mp -R _g tanφ _yaw

In [Equation 19], R _g represents the length of the received wave 2 projected onto the ground surface GR.

Referring back to FIGS. 17 and 18, point A (x _A , y _A ) in [Equation 19] is represented by (x' _i ,y' _j ) corresponding to the segment raw data, and point B (x _B , y _B ) May be represented by (x _i ,y _j ) corresponding to the corrected segment data. Point A(x' _i ,y' _j ) is corrected by point B(x _i ,y _j ) on the propagation in-phase line (6) where the vertical in-phase plane (5) of the transmitting wave (2) is in contact with the ground surface (GR) It should be, and referring to [Equation 14], the x-axis coordinate x _i of the point B can be expressed as [Equation 20].

[Equation 20]

Similarly, in [Equation 19] and [Equation 20], instead of the point A(xi', yj') corresponding to the segment raw data, the point B(xi, yj) corresponding to the corrected segment data is expressed as [Equation 21 ], [Equation 22].

[Equation 21]

[Equation 22]

The correction data generation unit 270 generates the corrected segment data in consideration of the orientation angle from the segment raw data using [Equation 19] to [Equation 22]. In this embodiment, the correction data generation unit 270 repeatedly calculates [Equation 19] to [Equation 22] through numerical analysis, so that the i, j-th pixels (coordinates (x _i , y _j )) in the FMCW-SAR image Restore. The correction data generator 270 may generate corrected segment data for each of the M segment raw data, and add the corrected segment data to obtain the corrected composite opening surface image data. In this embodiment, the correction data generation unit 270 corrects the position of each pixel using [Equation 19] and [Equation 20], and each corrected segment using [Equation 21] and [Equation 22]. Together, the process of performing backprojection of data is performed.

The image restoration unit 280 receives the corrected segment data by summing the inverse projection function f(x _i , y _j ) for each pixel generated by the correction data generation unit 270 for each segment, and receives M corrected segment data. The segment data are summed and reconstructed into a corrected image on the composite opening surface.

In this embodiment, it is shown that the preliminary reverse projection unit 220, the preliminary image restoration unit 230, and the correction data generation unit 270 are divided. A person with ordinary knowledge and experience in the art can use the same hardware to perform the functions of the preliminary reverse projection unit 220, the preliminary image restoration unit 230, and the correction data generation unit 270 as one component or two. It will be appreciated that it can be divided into three components.

Hereinafter, a split image restoration method using an aircraft-based split image restoration apparatus according to an embodiment of the present invention will be described.

FIG. 19 is a flowchart illustrating a method of restoring a segmented image using the aircraft-based segmented image restoration device shown in FIG. 1.

1 to 19, in the split image restoration method using an aircraft-based split image restoration apparatus, a transmission wave 2 is first transmitted to an irradiation reference point f(x _c , y _c ) on the ground surface (S100).

Specifically, in order to generate the transmission wave 2, a signal having the same waveform as the transmission wave 2 is generated using the waveform generator 150.

The signal having the same waveform as the transmission wave 2 generated from the waveform generator 150 is distributed to the transmission antenna 110 and the mixer 205 using the divider 160 (step S110).

Among the signals distributed using the divider 160, a signal applied to the transmission antenna 110 becomes a transmission wave 2 and is transmitted to the irradiation reference point f(x _c , y _c ) on the ground surface.

Subsequently, the received wave 4 reflected from the irradiation reference point f(x _c , y _c ) on the ground surface is received using the receiving antenna 120 (step S110).

Thereafter, raw data is generated from the received wave 4 (step S120).

Specifically, the distributed signal received from the distributor 160 and the received wave 4 received from the receiving antenna 120 are mixed using the mixer 205.

By using the raw data generator 210 from a signal mixed by the mixer 205 measures the respective pixels _{(x 'i, y' j} ) by the distance of the surface to calculate the [formula 1] to [Expression 4] To generate raw data S _IF , _r (t, u') representing the distances for each pixel (x' _i , _y'j ).

Subsequently, the raw data S _IF , _r (t, u') are divided according to a preset spatial reference value M using the shaking motion correction unit 290 to generate a plurality of divided raw data (S125).

Subsequently, each segment preliminary image is generated by back-projecting each segment raw data (S130).

Specifically, each section of the FMCW-SAR is applied by applying the raw data of each section approved from the original data generation section 210 using the preliminary reverse projection unit 220 to [Equation 17] and [Equation 18] to perform a matching filter process. The i and j-th pixels (coordinates (x' _i ,y' _j )) corresponding to the preliminary image are restored.

The reverse projection function f(x' _i ,y' _j ) for each pixel (x' _i ,y' _j ) corresponding to each segment preliminary image obtained by the preliminary reverse projection unit 220 is the preliminary image restoration unit 230 It is reconstructed as a preliminary image on the compartment synthesis opening surface.

Thereafter, it is determined whether or not an orientation angle error exists in each of the segment preliminary images by analyzing each segment preliminary image (S140).

Specifically, by analyzing the reconstructed preliminary image for each segment using the error determination unit 240, the point where the intensity of the reflected wave 4 is high is set as the investigation reference point f(x _c , y _c ), and the investigation reference point f(x _{Based on c} , y _c ), it examines whether the vertical line and the horizontal line intersect, and determines whether or not there is an error due to the orientation angle error and/or the aircraft oscillation. If the vertical line and the horizontal line intersect based on the survey control point f(x _c , y _c ) in each section preliminary image, it is judged that there is no error due to the orientation angle error or the aircraft oscillation, and the survey control point f (x _When two straight lines inclined based on _c , y _c ) intersect, it is judged that there is an error due to a heading angle error or aircraft oscillation.

When there is no error due to the orientation angle error or the aircraft oscillation, the preliminary images for each section are combined and output as a final image (S150).

When there is an error due to the orientation angle error or the aircraft oscillation, the distance direction rotation angle (φ _rg ) and the azimuth direction rotation angle (φ _yaw ) for each compartment preliminary image are analyzed by analyzing each compartment preliminary image (S160).

Specifically, by optically analyzing each segment preliminary image obtained by the preliminary image restoration unit 230 using the distance direction rotation component detection unit 250, the distance direction component of each segment preliminary image is the ideal distance direction (horizontal direction on the graph). Set the angle inclined from) to the distance direction rotation angle (φ _rg ) of the preliminary section.

In addition, by optically analyzing each segment preliminary image obtained by the preliminary image restoration unit 230 using the azimuth direction rotation component detection unit 260, the azimuth direction component of each segment preliminary image is the ideal azimuth direction (vertical direction on the graph). The angle inclined from is set as the azimuth rotation angle (φ _yaw ) of the preliminary image.

Subsequently, corrected segment data is generated in consideration of the error of the orientation angle and/or the error due to the motion of the aircraft (S170).

Specifically, each division raw data, each distance direction rotation angle (φ _rg ), and each azimuth direction rotation angle (φ _yaw ) are applied to [Equation 19] to [Equation 22] using the correction data generation unit 270 As a result, corrected segment data having the corrected reverse projection function f(x _i , y _j ) for each pixel is generated. In this embodiment, the corrected segment data has a form of reverse projection (BPA).

Subsequently, a corrected image is generated by combining the segment synthesis opening surface obtained from the corrected segment data (S180).

Specifically, by using the image restoration unit 280, the corrected segment data obtained by the correction data generating unit 270 is restored to a corrected image on the segment synthesis opening surface. In this embodiment, the corrected segment data has the form of an inverse projection function f(x _i ,y _j ) for each pixel.

According to an embodiment of the present invention as described above, in the aircraft-based segmented image restoration apparatus, even if a direction angle error occurs due to a twisted irradiation direction of a radar, or an error due to aircraft oscillation occurs, corrected reverse projection without separate physical measures You can get the image.

Since it is virtually impossible to remove the orientation angle error or the error due to the aircraft fluctuation through cross-validation due to the characteristic that the propagation phase plane propagates in a twisted state to the ground surface, conventionally, if errors due to the orientation angle error and/or aircraft fluctuation are found. Data was discarded without being able to be reused. Therefore, conventionally, if an error due to orientation angle error or aircraft fluctuation is found in the reverse-projected image, it is necessary to adjust the direction of the transmission antenna and then leave the aircraft again to obtain new data. And cost. However, according to the embodiment of the present invention, since it is possible to obtain a back-projection image in which an error due to a directing angle error and/or an error due to aircraft oscillation is eliminated by using the data obtained in one operation, time and cost are reduced.

The aircraft-based segmented image restoration apparatus according to an embodiment of the present invention includes an antenna member 110 and 120, a waveform generator 150, a distributor 160, a mixer 205, a raw data generator 210, and a vibration correction unit ( 290), preliminary reverse projection unit 220, preliminary image restoration unit 230, error determination unit 240, distance direction rotation component detection unit 250, azimuth direction rotation component detection unit 260, correction data generation unit 270 , And a correction image restoration unit 280. In another embodiment, the preliminary reverse projection unit 220 is replaced with an integrated reverse projection unit (not shown), and the integrated reverse projection unit (not shown) performs a preliminary matching filter process using segment raw data and correction using the corrected segment data It is also possible to perform the matched filter process together. In addition, the preliminary image restoration unit 230 is replaced with an integrated image restoration unit (not shown), and the integrated image restoration unit (not shown) provides a function of displaying the preliminary image and the corrected image on the compartment synthesis opening surface. You can also perform the display function together.

Experimental example

FIG. 20 is a graph showing a reverse projection image having a resolution of 0.2m horizontally and vertically when an aircraft moves a flight path having a sine function with an amplitude of 5m to the left and right with a length of 200m and an orientation angle error of 3°. 21 is a full-aperture image obtained by performing reverse-projection (BPA) of all the segmented raw data of FIG. 20 as it is through a matching filter process. In Figs. 20 and 21, the error due to the orientation angle error and the aircraft oscillation are summed, and if only the part due to the orientation angle error is projected and extracted from the summed error on the ground surface, the part due to the theoretical orientation angle error in the restored image Becomes 2.122°.

Referring to Figs. 20 and 21, the horizontal and vertical lines are distorted because the orientation angle error and the error due to the aircraft oscillation are included together.

FIG. 22 is a reverse projection image in the case of performing a matching filter process by using a division calculation technique by dividing raw data in the case of only aircraft oscillation without an orientation angle error (0°) in FIG. 20 and setting the division raw data 22 shows a reverse projection image when the original data of FIG. 20 is divided into four to use a division operation technique, and a matching filter process is performed by setting the divided raw data. Comparing FIGS. 22 and 23, a portion due only to the orientation angle error in the reconstructed image can be obtained.

Referring to FIGS. 22 and 23, the angle of the sum of the error of the orientation angle and the error due to the aircraft oscillation was 4.3596°, and the angle due only to the error due to the aircraft oscillation without the directivity angle error was 6.4327°.

If the angle of FIG. 22 was subtracted from the angle of FIG. 23 and the angle due to the directing angle error was obtained, it was 2.13°, which was almost similar to the theoretical angle of 2.122° obtained when the directing angle 3° was projected onto the ground surface.

As described above, in the case of the embodiment of the present invention, it is possible to accurately analyze the error due to the orientation angle error and the aircraft oscillation.

According to an embodiment of the present invention as described above, in the aircraft-based segmented image restoration apparatus, even if a direction angle error occurs due to a twisted irradiation direction of a radar, or an error due to aircraft oscillation occurs, corrected reverse projection without separate physical measures You can get the image.

Since it is virtually impossible to remove the orientation angle error or the error due to the aircraft fluctuation through cross-validation due to the characteristic that the propagation phase plane propagates in a twisted state to the ground surface, conventionally, if errors due to the orientation angle error and/or aircraft fluctuation are found. Data was discarded without being able to be reused. Therefore, conventionally, if an error due to orientation angle error or aircraft fluctuation is found in the reverse-projected image, it is necessary to adjust the direction of the transmission antenna and then leave the aircraft again to obtain new data. And cost. However, according to the embodiment of the present invention, since it is possible to obtain a back-projection image in which an error due to a directing angle error and/or an error due to aircraft oscillation is eliminated by using the data obtained in one operation, time and cost are reduced.

Errors caused by aircraft fluctuations basically have the same aspect as the orientation angle error when differentiating aircraft operation. That is, the error caused by the aircraft oscillation caused by tilting the antenna member during the inclining process of the aircraft and the directing angle error caused by tilting the antenna member itself show the same result in terms of raw data. However, the orientation angle error is inclined at the same angle throughout the flight of the aircraft, but the only difference is that the error due to aircraft fluctuation changes with time.

In the present invention, by dividing the raw data obtained in the course of aircraft operation and dividing it into a kind of derivative, errors due to aircraft fluctuations are treated in the same manner as the orientation angle error.

In addition, by performing the preliminary matching filter process and the correction matching filter process together using one integrated reverse projection unit, the structure of the aircraft-based segmented image restoration apparatus is simplified and cost is reduced.

The present invention has industrial applicability that can be used for purposes such as aerial view, topographic map creation, marine exploration, remote exploration, satellite exploration, aircraft exploration, exploration using floating test equipment, bird exploration, meteorological exploration, military use, and the like.

Although the above has been described with reference to Examples, those skilled in the art can variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the scope of the utility model registration request below. You will understand that there is.

5: radio wave in-phase plane 6: radio wave in-phase line
6': projection line 110, 120: antenna member
150: waveform generator 160: divider
205: mixer 210: raw data generation unit
220: reserve reverse projection section 1220: integrated reverse projection section
230: preliminary image restoration unit 1230: integrated image restoration unit
240: error determination unit 250: distance direction rotation component detection unit
260: azimuth direction rotation component detection unit 270, 1270: correction data generation unit
280: Correction image restoration unit 290: Yodong correction unit
Gr: surface f(x ₀ , y ₀ ): irradiation point
f(x _c , y _c ): Reference point φ _rg : Rotation component in distance direction
φ _yaw : Directional rotation component φ _sq : Directional angle

Claims (10)

A waveform generator that generates a signal having the same waveform as the transmission wave;
A divider connected to the waveform generator and configured to receive and distribute a signal generated from the waveform generator;
An antenna member connected to the distributor and including a transmission antenna for receiving the distributed signal from the distributor and transmitting the transmission wave to the ground surface, and a reception antenna for receiving a reception wave reflected from the ground surface;
A mixer connected to the distributor and the reception antenna, and mixing the distributed signal received from the distributor and the reception wave received from the reception antenna;
A raw data generator connected to the mixer, receiving the mixed signal from the mixer, measuring a distance of each pixel on the ground surface, and generating raw data corresponding to the received signal for each pixel;
A shaking motion correction unit connected to the raw data generating unit and generating a plurality of partition raw data by dividing the raw data according to a preset spatial reference value;
A preliminary reverse projection unit for calculating a plurality of pre-correction reverse projection functions (f( _x'i , _y'j )) by performing a matching filter process for each of the segment raw data;
Preliminary image restoration in which each of the pre-correction reverse projection functions (f(x' _i , _y'j )) is projected onto the composite opening as a preliminary image for each pixel to generate a partition preliminary image for each of the divided composite openings part;
A distance direction rotation component detection unit for setting an angle in which the distance direction component of each of the preliminary sections is inclined from an ideal distance direction as a distance direction rotation angle of the preliminary section images;
An azimuth direction rotation component detection unit for setting an angle in which the azimuth direction component of each of the subdivision preliminary images is inclined from an ideal azimuth direction as an azimuth direction rotation angle of the corresponding subdivision preliminary image; And
The positions of the respective pixels are corrected using the distance direction rotation angle and the azimuth rotation angle for each of the preliminary division images, and the position of the reverse projection function (f(x _i , y _j )) for each corrected pixel A correction data generator configured to generate the corrected reverse projection function (f(x _i ,y _j )) for each pixel as corrected segment data by performing a matching filter process for each segment preliminary image according to the method,
((x' _i ,y' _j ) represents the position (coordinate) of the i,j-th pixel on the raw data, and (x _i ,y _j ) represents the coordinates of the i,j-th pixel corrected on the composite opening surface. Indicates)
The preliminary reverse projection unit performs the matching filter processes of [Equation 1] and [Equation 2] on the raw data (S _IF,r (ω, _u'Mp ); ω is the frequency, _u'Mp is the position of the receiving antenna)). And calculate the pre-correction reverse projection function f(x' _i ,y' _j ) for each pixel (x' _i ,y' _j ) for each segmented raw data,
[Equation 1]

[Equation 2]

(In [Equation 1] and [Equation 2], K denotes the number of segmented raw data divided by 1/M by the shaking _{motion compensation unit} , and _u'Mp denotes the position of the receiving antenna at the time the p-th received wave is received. And t _dij represents the delay time of the i,j-th pixel, (x' _i ,y' _j ) represents the position (coordinate) of the i,j-th pixel on the raw data, and Wp is the signal measured by the receiving antenna denotes a window function of the intensity, t denotes a sampling time, ω denotes the frequency, u _'Mp denotes the location of the receiving antenna mounted on the aircraft in each block of raw _{data, S IF, r (ω,} u _'Mp) is the receive antenna u' the delay time of the received signal represents the raw data for a, t _dij (u _'Mp) is located (u of the receive antennas mounted on the aircraft' _Mp) of the case which is located _Mp Indicate)
The correction data generation unit performs a matching filter process of [Equation 3] to [Equation 6] on the raw data (S _IF,r (ω, _u'Mp )) to each corrected pixel (x _i , y _j ). An inverse projection function f(x _i , y _j ) is generated as corrected segment data, and the corrected segment data is projected for each of the corrected pixels (x _i , y _j ) to obtain the corrected image on the composite opening surface. Aircraft-based split image restoration device, characterized in that to generate.
[Equation 3]
_u'Mp =u _Mp -R _g tanφ _yaw
[Equation 4]

[Equation 5]

[Equation 6]

(In [Equation 3] to [Equation 6], u _Mp (u _x , u _y , u _z ) represents the coordinates corrected for the position of the reception antenna at the time point at which the p-th received wave is received, and u _Mp (u' _{x, u 'y, u'} z) represents the coordinates p-th received wave does not correct the position of the receiving antenna at the point to be received, R _g indicates the length of the received wave projected onto the ground surface, (x _c, y _c ) represents the coordinates of the reference point on the ground surface, (x _i ,y _j ) represents the coordinates of the corrected i,jth pixel, and f(x _i ,y _j ) represents the corrected i,jth reverse projection Represents a function) delete delete The method of claim 1, wherein the correction data generator reconstructs the i,j-th coordinates in the frequency modulated continuous wave-synthetic aperture radar (FMCW-SAR) image by repeatedly calculating [Equation 3] to [Equation 6] through numerical analysis. Aircraft-based split image restoration device, characterized in that. The method of claim 1, wherein the distance direction rotation component detection unit sets the horizontal direction of each preliminary image to the distance direction, and sets an angle in which the distance direction component is inclined from the horizontal direction as the distance direction rotation angle (φ _rg ). Aircraft-based split image restoration device, characterized in that. The azimuth direction rotation component detection unit of claim 1, wherein the azimuth direction rotation component detection unit sets a vertical direction of each preliminary image to an azimuth direction, and sets an angle in which the azimuth direction component is inclined from the vertical direction as the azimuth direction rotation angle (φ _yaw ). Aircraft-based split image restoration device, characterized in that. The aircraft-based segmented image restoration apparatus according to claim 1, wherein the raw data includes FMCW-SAR (Frequency Modulated Continuous Wave-Synthetic Aperture Rader) data measured by an aircraft. An antenna member including a transmission antenna that transmits a transmission wave to the ground surface and a reception antenna that receives a reception wave reflected from the ground surface, and receives the reception wave by measuring a distance for each pixel on the ground surface to receive each pixel A raw data generator for generating raw data corresponding to a signal, a motion correction part for generating a plurality of segment raw data by receiving the raw data, and reverse projection for each pixel for each segment raw data by performing a matching filter process A reverse projection unit for calculating a function; an image restoration unit for generating an image on a composite opening surface by projecting the reverse projection function for each pixel of each of the raw data; and a propagation in-phase plane of the received wave for each of the divided raw data A distance direction rotation component detection unit that sets the angle at which the radio wave motion phase line in contact with the ground surface is inclined as a distance direction rotation angle, and the angle at which the projection line vertically projecting the received wave onto the ground surface for each segment raw data is inclined. An aircraft-based aircraft comprising an azimuth rotation component detection unit for setting an azimuth rotation angle, and a correction data generation unit for correcting the position of each pixel using the distance direction rotation angle and the azimuth rotation angle for each segment raw data In the split image restoration method using the split image restoration device,
Transmitting the transmission wave onto the ground surface using the transmission antenna and receiving the received wave reflected from the ground surface through the reception antenna;
Generating raw data corresponding to the received signal for each pixel by measuring a distance for each pixel between the receiving antenna and the ground surface using the received wave;
Generating the divided raw data by dividing the raw data according to a predetermined spatial reference value using the shaking motion correction unit;
Generating partition preliminary images by performing a matching filter process on the respective partition raw data using the reverse projection unit and the image restoration unit;
Applying the respective segment preliminary images to the distance direction rotation component detection unit to set a distance direction rotation angle for each segment preliminary image;
Setting an azimuth rotation angle for each of the compartment preliminary images by applying the respective partition preliminary images to the azimuth direction rotation component detection unit;
Applying the distance direction rotation angle and the azimuth direction rotation angle to the correction data generator for each of the divided raw data to correct the positions of the pixels for each of the divided raw data; And
A matching filter process is performed according to the position of each corrected pixel for each of the divided raw data, and each of the divided data subjected to the matching filter process for each of the divided raw data is projected onto the composite opening surface for each of the corrected pixels. And generating a corrected image on the composite opening surface,
The step of generating the segment preliminary images by performing a matching filter process on each segment raw data includes the raw data (S _IF,r (ω, _u'Mp ); ω is the frequency, _u'Mp is the position of the receiving antenna) ) By performing the matching filter process of [Equation 1] and [Equation 2], the inverse projection function f(x' _i ,y' _j ) before correction for each pixel (x' _i ,y' _j ) for each segmented raw data ),
[Equation 1]

[Equation 2]

(In [Equation 1] and [Equation 2], K denotes the number of segmented raw data divided by 1/M by the shaking _{motion compensation unit} , and _u'Mp denotes the position of the receiving antenna at the time the p-th received wave is received. And t _dij represents the delay time of the i,j-th pixel, (x' _i ,y' _j ) represents the position (coordinate) of the i,j-th pixel on the raw data, and Wp is the signal measured by the receiving antenna denotes a window function of the intensity, t denotes a sampling time, ω denotes the frequency, u _'Mp denotes the location of the receiving antenna mounted on the aircraft in each block of raw _{data, S IF, r (ω,} u _'Mp) is the receive antenna u' the delay time of the received signal represents the raw data for a, t _dij (u _'Mp) is located (u of the receive antennas mounted on the aircraft' _Mp) of the case which is located _Mp Indicate)
The step of correcting the position of each pixel for each segment raw data includes performing the matching filter process of [Equation 3] to [Equation 6] on the raw data (S _IF,r (ω, _u'Mp )). the corrected pixel (x _i, y _j) by back-projection function f (x _i, y _j) to produce a corrected segment data and projected by each of the corrected pixel (x _i, y _j) the corrected segment data And generating the corrected image on the composite opening surface.
[Equation 3]
_u'Mp =u _Mp -R _g tanφ _yaw
[Equation 4]

[Equation 5]

[Equation 6]

(In [Equation 3] to [Equation 6], u _Mp (u _x , u _y , u _z ) represents the coordinates corrected for the position of the reception antenna at the time point at which the p-th received wave is received, and u _Mp (u' _{x, u 'y, u'} z) represents the coordinates p-th received wave does not correct the position of the receiving antenna at the point to be received, R _g indicates the length of the received wave projected onto the ground surface, (x _c, y _c ) represents the coordinates of the reference point on the ground surface, (x _i ,y _j ) represents the coordinates of the corrected i,jth pixel, and f(x _i ,y _j ) represents the corrected i,jth reverse projection Represents a function)
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