KR101712084B1 - Method and Apparatus for Correcting Ionospheric Distortion based on multiple aperture interferometry - Google Patents

Abstract

The present invention relates to a method and an apparatus for correcting ion distortion based on a multi-interference technique, and more particularly, to a method and an apparatus for correcting ion distortion based on a multi-interference technique based on a multi- A method for correcting ion distortion, and a device therefor.
In order to achieve the above object, an ion distortion correction apparatus based on a multi-interference technique according to an embodiment of the present invention calculates a differential value for a flight direction from a satellite radar interference map produced using SAR (Synthetic Aperture Radar) A filtered directional phase difference calculation unit, a filtered MAI interference degree acquisition unit that obtains a filtered MAI interference degree using a multiple aperture interferometry (MAI) interference degree produced using the satellite radar interference degree, a differential value And a model generating unit for generating a model including an ion distortion phase and an orbital distortion phase based on the filtered MAI interference degree, and a model generating unit for generating an integrated MAI interference map by integrating the filtered MAI interference map based on the generated model, An integrated MAI interference level acquiring unit for acquiring the satellite radar interference level, Satellite radar interference correction for obtaining a degree of coherence may also include an acquisition.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and an apparatus for correcting ion distortion based on a multi-

The present invention relates to a method and an apparatus for correcting ion distortion based on a multi-interference technique, and more particularly, to a method and an apparatus for correcting ion distortion based on a multi-interference technique based on a multi- A method for correcting ion distortion, and a device therefor.

The satellite radar interference techniques developed in recent years (Interferometric Synthetic Aperture Radar; InSAR) has been successfully used to observe the number of surface displacements said Genie a measurement sensitivity of about sip km ² be greater than or equal to the number of cm to over a wide area mm in two dimensions come.

Over the past 15 years, radar interference techniques have been used for earthquakes, volcanoes, glaciers, landslides, groundwater pumping, landfill subsidence, and abandoned mine sinks. The data generated by this radar interference technique is called radar interference, from which it is possible to observe the precise surface displacement with the line-of-sight (LOS) of the antenna.

However, since this technique can only observe one-dimensional surface displacements in the observation direction, there is a limit to the three-dimensional analysis of the mechanism of surface displacement in seismic activity, volcanic eruption, landslide, and glacier movement. Many researchers have been actively studying 2D or 3D surface displacements to overcome these drawbacks.

For example, there has been proposed a method of determining the landward displacement in the direction of the ground range and the vertical direction of the land by using radar interferometry from a plurality of images having different paths, There is a drawback that it can not be done. In addition, a method of using the correlation coefficient between two images or several images has been proposed in order to observe the three-dimensional surface displacement, but the accuracy of the measured surface displacement is very low and can be applied only to surface displacements of several tens cm or more.

Meanwhile, the MAI (multi-aperture interferometry) technique, which improves the accuracy of observation of the displacement of the surface in the newly developed flight direction, produces forward-looking interference and backward-looking interference through split-beam InSAR processing. Lt; RTI ID = 0.0 > MAI < / RTI > This method is very accurate compared with the method using the correlation coefficient. In case of using the ERS SAR satellite image, the indicator displacement in the flight direction can be observed with a precision of about 8 cm at a coherence of 0.6, When ALOS PALSAR satellite images are used, it is known that 3-D surface displacements can be observed with accuracy of about 2 cm in the east and vertical directions and about 4 cm or less in the north direction.

In Korean Patent No. 10-1111689 entitled " 3-Dimensional Surface Displacement Extraction Method and Apparatus ", satellite radar interference and MAI interference are used to extract the gaze direction displacement and the flight direction displacement, A technique for accurately extracting displacement is presented.

However, although the prior art has an advantage in that it can observe precise displacement of the land using the satellite radar interference degree, there is a disadvantage that the satellite radar interference degree can be seriously distorted by the change of the ion layer due to the stripe effect . That is, the prior art has proposed an effort to eliminate the flat phase and the altitude phase and remove the residual phase caused by the matching error in the process of manufacturing the MAI data, but the distortion effect due to the change of the ionosphere But it has not been solved fundamentally.

Distortion in the satellite radar interference figure should be corrected, but until now there has not been developed a technique that can efficiently remove the ion layer distortion due to the precision problem. Accordingly, there is a need for a technique capable of satisfying the accuracy while correcting the phenomenon of ion layer distortion appearing in the satellite radar interference degree.

Korean Registered Patent No. 10-1111689 (Registered on Feb. 2015)

It is an object of the present invention to provide a method and an apparatus for correcting ion distortion based on a multi-interference technique.

An object of the present invention is to supplement the ion distortion correction technique based on the multi-interference technique so as to obtain a better quality radar image for an image including an area where interference can not be generated, such as the sea and the lake.

The present invention relates to a technique capable of improving the quality of satellite radar interference and a technique applicable to various environments and disaster observation fields such as land surface displacement observation, landslide observation, tree height observation, ground subsidence observation, The purpose of this paper is to provide

The present invention aims at acquiring a radar image with higher accuracy and usability by simultaneously calculating an error component due to satellite orbit error and ion layer phase distortion.

The object of the present invention is to compensate for the disadvantage that discontinuity may appear in the flight direction adjacent pixels by simultaneously considering the viewing direction and the flying direction in the process of determining the integral constant.

In order to achieve the above object, an ion distortion correction apparatus based on a multi-interference technique according to an embodiment of the present invention calculates a differential value for a flight direction from a satellite radar interference map produced using SAR (Synthetic Aperture Radar) A filtered directional phase difference calculation unit, a filtered MAI interference degree acquisition unit that obtains a filtered MAI interference degree using a multiple aperture interferometry (MAI) interference degree produced using the satellite radar interference degree, a differential value And a model generating unit for generating a model including an ion distortion phase and an orbital distortion phase based on the filtered MAI interference degree, and a model generating unit for generating an integrated MAI interference map by integrating the filtered MAI interference map based on the generated model, An integrated MAI interference level acquiring unit for acquiring the satellite radar interference level, Satellite radar interference correction for obtaining a degree of coherence may also include an acquisition.

In this case, the integrated MAI interference level acquisition unit estimates the integration constant included in the integrated MAI interference level in consideration of the azimuth direction and the range direction based on the multiple regression equation, Wherein the controller is operable to reduce an integration error of the azimuth direction due to the noise of the filtered MAI interference degree and to remove an orbital distortion phase of the satellite radar interference degree, The value of the ion distortion phase and the value of the orbital distortion phase can be calculated.

The model generator may generate the model including the ion distortion phase and the orbital distortion phase using a quadratic polynomial model, and the model including the ion distortion phase and the orbital distortion phase may be generated by the satellite radar The interference and the filtered MAI interference may also be generated for each. In addition, the flight direction phase difference calculation unit may calculate the phase difference of the satellite radar interference degree along the flight direction by using an azimuth direction and a range direction in the SAR image.

The filtered MAI interference level acquisition unit may mask and remove the surface displacement distortion phase and the atmospheric distortion phase included in the satellite radar interference level and the surface displacement distortion phase included in the MAI interference level, The filtered MAI interference level can be obtained by masking an area having low coherence or a large area locally in the MAI interference degree and then applying a directional filter.

Also, the filtered MAI interference level obtaining unit may use the MAI interference level produced by using the phase difference between the front observation radar interference and the rear observation radar interference of the satellite radar interference degree, The front observation SAR image is generated by compressing only the number of times observed from the front of the center of the beam during the number of times the center of the beam is captured, and the front observation radar interference generated from the calculated phase difference by observing the forward observation SAR image twice, A rear observation SAR image is produced by compressing only the number of times observed from the rear of the center of the beam among the number of times the first target is photographed, and the rear observation radar interference generated from the calculated phase difference by observing the rear observation SAR image twice The MAI interference figure may be used.

Meanwhile, a method for correcting ion distortion based on a multi-interference technique according to an embodiment of the present invention includes calculating a differential value for a flight direction from a satellite radar interference map produced using a SAR (Synthetic Aperture Radar) image, Obtaining a filtered MAI interferometry using a multiple aperture interferometry (MAI) interferometry produced using a radar interference diagram, calculating an ion distortion phase And generating a model including an orbital distortion phase; integrating the filtered MAI interference figure based on the generated model to obtain an integrated MAI interference map; And removing the MAI interference to obtain a corrected satellite radar interference figure.

In this case, the step of acquiring the integrated MAI interference degree includes estimating an integration constant included in the integrated MAI interference degree in consideration of an azimuth direction and a range direction based on a multiple regression equation And the integration error of the azimuth direction due to the noise of the filtered MAI interference degree is reduced through the integration constant and the orbital distortion phase of the satellite radar interference degree can be removed. In addition, the step of acquiring the integrated MAI interference figure may calculate the values of the ion distortion phase and the orbital distortion phase included in the satellite radar interference diagram through the integrated MAI interference diagram.

Also, the generating of the model may generate the model including the ion distortion phase and the orbital distortion phase using a quadratic polynomial model, and the model including the ion distortion phase and the orbital distortion phase Satellite radar interference and the filtered MAI interference may also be generated for each. In addition, the step of calculating the derivative value with respect to the flight direction may calculate a phase difference of the satellite radar interference according to the flight direction using an azimuth direction and a range direction in the SAR image.

In addition, the step of acquiring the filtered MAI interference degree may include masking and removing the surface displacement distortion phase and the atmospheric distortion phase included in the satellite radar interference map, and the surface displacement distortion phase included in the MAI interference map And the filtered MAI interference level can be obtained by masking an area having a low degree of coherence or a large area locally in the MAI interference degree and then applying a directional filter thereto .

In addition, the step of acquiring the filtered MAI interference degree may use the MAI interference degree produced by using the front observation radar interference of the satellite radar interference degree and the phase difference of the rear observation radar interference degree. To this end, the step of acquiring the filtered MAI interference degree produces a forward observation SAR image by compressing only the number of times observed from the front of the center of the beam among the number of times the SAR sensor has photographed the first target, Generating a backward observation SAR image by compressing only the number of times observed from the rear of the center of the beam among the number of times the SAR sensor has photographed the first target, Generating a rear observation radar interference figure from the calculated phase difference by observing the rear observation SAR image twice and generating the MAI interference degree using the front observation radar interference and the rear observation radar interference degree; Step < / RTI >

The present invention relates to a method and an apparatus for correcting ion distortion based on a multi-interference technique, and is capable of acquiring a better quality radar image for an image including an area where interference can not be generated, such as sea and lake.

The present invention can be applied to a variety of environments and disaster observation fields such as an indicator displacement observation, a landslide observation, a tree height observation, and a subsidence observation which can utilize satellite radar interference degree as a source technology for improving the quality of satellite radar interference. There is an effect.

The present invention has the effect of acquiring more accurate and usable radar images by simultaneously compensating the ion distortion correction technique based on the multi-interference technique by simultaneously calculating the error components due to the satellite orbit error and the ion-phase phase distortion.

In the process of determining the integral constant, the present invention takes into account both the viewing direction and the flying direction, thereby making it possible to compensate for the disadvantage that discontinuity may appear in the adjacent pixels in the flight direction.

The present invention reduces the error by establishing a model including the satellite orbit error and the ionospheric distortion error, and corrects the ionospheric distortion even in the image including the region where interference generation is impossible by using the direction filter, Ion distortion correction can be applied to various regions.

The present invention can be used for more accurate measurement of surface displacement and ground subsidence by acquiring a good quality radar interference degree. In particular, when calculating the time series surface displacement, the result is changed according to the radar interference degree. There is an effect that can be applied to various fields.

A lot of efforts are being made to obtain satellite radar images by installing radar sensors on satellites not only in Korea but also around the world, and many satellites equipped with long-wave band radar sensors will be launched. However, in the case of a radar image system with a long wavelength band, errors due to the ionosphere are very large, and a method for solving the problem is needed. Accordingly, the present invention has the effect of improving the usability of the radar image of the long wavelength band.

The present invention has the effect of reducing the error caused by the ionosphere in the satellite radar, contributing to expansion of the national satellite industry and activation of related companies.

1 is a schematic block diagram of an ion distortion correction apparatus based on a multi-interference technique according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a method for correcting ion distortion based on a multi-interference technique according to an embodiment of the present invention.
FIG. 3 is a view showing a data acquisition area and a coherence map of ALOS PALSAR according to one embodiment of the present invention.
4 is a diagram illustrating a satellite radar interference map, a MAI interference map, and a filtered MAI interference map generated according to an embodiment of the present invention.
FIG. 5 is a diagram showing a flight direction differential image, an image including an ionospheric distortion phase and an orbital distortion phase, and an orbital distortion phase image using a second-order polynomial model generated according to an embodiment of the present invention.
6 is a diagram showing an interferogram image of a satellite radar interference diagram (InSAR) generated according to an embodiment of the present invention and an interferogram image of InSAR generated by correcting only the orbital distortion phase.
FIG. 7 is a view showing a profile value distribution in a flight direction for analyzing a correction effect of a phase error by an ion layer according to an embodiment of the present invention. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In the following description of the embodiments of the present invention, specific values are only examples.

The radar interference degree includes various errors such as atmospheric error, satellite orbit error, and processing error. Particularly, since the phase delay error due to the ion layer is proportional to the wavelength, correction of the above- .

However, since the correction method using the linear relationship between the radar interference and the MAI interference in the ionospheric phase error correction technique based on the multi-aperture interferometry (MAI) does not consider the error due to the phase trajectory, There is a problem that the radar interference degree is not corrected properly when the MAI interference degree includes a large area such as a lake or sea where interference can not be generated.

Accordingly, it is an object of the present invention to provide a method and an apparatus for correcting ion distortion based on a multi-interference technique in which a phase orbit error is taken into consideration, more specifically, to simultaneously calculate error components due to satellite orbit error and ion- A directional filter is applied to an image including an area in which no image can be generated, thereby providing a technique capable of obtaining a good quality radar interference degree with improved accuracy.

1 is a schematic block diagram of an ion distortion correction apparatus based on a multi-interference technique according to an embodiment of the present invention.

Referring to FIG. 1, an ion distortion correction apparatus 100 based on a multi-interference technique according to an exemplary embodiment of the present invention includes a satellite radar interference pattern production unit 110, a MAI interference pattern production unit 120, And may include a calculation unit 130, a filtered MAI interference level acquisition unit 140, a model generation unit 150, an error calculation unit 160, and a corrected satellite radar interference level acquisition unit 170, The radar interference figure production section 110 may include a front observation radar interference pattern production section 111 and a rear observation radar interference pattern production section 112. Each configuration is as follows.

The interferometric synthetic aperture radar (InSAR) production unit 110 includes a front observation radar interference plotting unit 111 and a rear observation radar interference plotting unit 112.

SAR (Synthetic Aperture Radar) image is a high resolution radar image produced by shooting a microwave from a sensor, capturing a target thousands of times and compressing it. SAR images are made up of complex numbers with magnitude and phase, the size means the reflectivity of the surface, and the phase means that it is expressed in one cycle of a sine or cosine curve. The satellite radar interference degree is data prepared from the phase difference of the SAR image by observing the SAR image twice. The method of producing such a satellite radar interference degree is well known in the field of the present invention, and will not be described below.

Forward-looking Radar Interference Mapping Unit 111 creates a forward observation SAR image by compressing only the number of times observed from the center of the beam in the number of times the SAR sensor has photographed a target, And the front-view radar interference figure is constructed from the calculated phase difference.

The backward-looking radar interference figure production unit 112 is fabricated in the same manner as the above-described production of the front observation radar interference figure, except that the number of times the SAR sensor observed from the rear of the center of the beam, And the backward observation SAR image is observed twice, and the backward observation radar interference is constructed from the phase difference calculated by observing the backward observation SAR image twice.

The multiple aperture interferometry (MAI) interference pattern generation unit 120 generates a frontal observation radar interference pattern and a rear observation radar interference pattern produced by the front observation radar interference pattern production unit 111 and a phase difference of the rear observation radar interference pattern produced by the rear observation radar interference production unit 1120 Calculate the MAI interference figure. The MAI interference degree is used to observe the surface displacement in the flight direction or the velocity of the object. The method of making the MAI interference degree is described in detail in Korean Patent No. 10-1111689, A description thereof will be omitted.

The filtered MAI interference level acquisition unit 140 may be configured to receive the MAI interference level from the MAI interference level produced by the MAI interference level production unit 120 in a region having a low coherence or a region having a large local displacement such as a sea, And then applying a directional filter to obtain a filtered MAI interference degree. That is, the filtered MAI interference level acquisition unit 140 applies a directional filter to the masked MAI interference level to obtain a filtered MAI interference level. In this case, when a specific pattern is seen in a diagonal direction (or vertical or horizontal direction) in the MAI interference diagram, the direction filter holds a pixel in the range (horizontal direction) and holds the pixel in the azimuth (vertical direction) (I.e., holding a pixel in a rectangular shape) to perform interpolation, i.e., performing interpolation while maintaining the pattern.

The filtered MAI interference degree obtaining section 140 applies a direction filter to an area where the Null value such as the sea or the lake is empty in the MAI interference diagram and thus the interference can not be generated, It is possible to generate a pattern value. In addition, the filtered MAI interference degree acquisition section 140 can obtain a filtered MAI interference degree with various kinds of noise reduced by applying a directional filter to the MAI interference degree.

In other words, by applying a directional filter to the MAI interference map, the present invention can be applied to a MAI interference map including regions where large values are locally large, or areas where interference can not be generated, such as low- It is possible to perform ionospheric distortion correction on the degree of interference.

Meanwhile, before generating the filtered MAI interference diagram, the following assumption may be made in the present invention.

That is, as described above, various errors (or distortions) are included in the radar interference degree. To provide an ion distortion correction apparatus 100 based on a multi-interference technique in which a phase orbit error is considered, The following assumptions are made in consideration of the satellite orbit error.

The satellite radar interference level produced by the satellite radar interference level production unit 110 can be expressed as Equation 1 below and the MAI interference level produced by the MAI interference level production unit 120 can be expressed as Equation 2 below.

[Formula 1]

[Formula 2]

)은 위성레이더 간섭도에서 이온층(ION)에 의한 왜곡 위상(

), 궤도 오차(ORB)에 의한 왜곡 위상(

), 지표변위(DEFOR)에 의한 왜곡 위상(

), 대기(TRO)에 의한 왜곡 위상(

)의 합으로 표현할 수 있다.In this case, in the case of Equation 1, the phase of the satellite radar interference degree (InSAR)

) Is the distortion phase due to the ionosphere (ION) in the satellite radar interference figure

), The distortion phase (ORB)

), The distortion phase due to the surface displacement (DEFOR)

), The distortion phase (TRO)

). ≪ / RTI >

)은 MAI 간섭도에서 이온층(ION)에 의한 왜곡 위상(

), 궤도 오차 (ORB)에 의한 왜곡 위상(

), 지표변위(DEFOR)에 의한 왜곡 위상(

)의 합으로 표현할 수 있다.In the case of Equation 2, the phase of the MAI interference figure

) Is the distortion phase due to the ion layer (ION) at the MAI interference level

), The distortion phase (ORB)

), The distortion phase due to the surface displacement (DEFOR)

). ≪ / RTI >

At this time, the filtered MAI interference degree obtaining section 140 of the present invention calculates the MAI interference degree from the DEFOR and DEFOR in the satellite radar interference diagram and the distortion component due to the atmosphere (TRO) ) Can be regarded as a noise component. In addition, the filtered MAI interference level acquisition unit 140 may remove the noise components locally generated as described above from the MAI interference level through masking. The filtered MAI interference level acquisition unit 140 ) May obtain a filtered MAI interference figure by applying a directional filter to the masked MAI interference map to perform interpolation.

)를 계산하며, 이는 식 22와 같이 정의된다.The flight direction phase difference calculation unit 130 calculates a differential value with respect to the flight direction from the satellite radar interference figure produced by the satellite radar interference level production unit 110. [ In other words, the flight direction phase difference calculation unit 130 calculates the phase difference of the satellite radar interference degree

), Which is defined as Equation (22).

[Formula 22]

Here, (x, r) denotes the position in the azimuth direction and the range direction in the SAR image coordinate system.

Next, the model generation unit 150 generates a model capable of simultaneously calculating the distortion component due to the ion layer and the distortion component due to the orbit error. That is, the model generating unit 150 can determine a model parameter between the satellite radar interference and the filtered MAI interference, and the model parameter value can be calculated in consideration of the distortion due to the orbit error. The model generation unit 150 generates the phase difference value of the satellite radar interference according to the flight direction calculated by the flight direction phase difference calculation unit 130 and the filtered MAI interference obtained by the filtered MAI interference level acquisition unit 140 The model parameters can be determined using the diagram. A more detailed description follows.

First, the distortion component due to the ion layer appearing in the satellite radar interference and the filtered MAI interference can be divided into a low frequency component and a high frequency component as shown in the following Equation 3 and Equation 4, respectively.

[Formula 3]

[Formula 4]

각각은 위성레이더 간섭도의 이온층에 의한 왜곡 위상(

)의 저주파 성분과 고주파 성분을 의미하며, 식 4에서

와

는 필터링된 MAI 간섭도의 이온층에 의한 왜곡 위상(

)의 저주파 성분과 고주파 성분을 의미한다.In this case, Wow

Each represents the distortion phase due to the ionosphere of satellite radar interference

) And the high-frequency component of Equation 4. In Equation 4,

Wow

Is the distortion phase due to the ionized layer of filtered MAI interference (

Frequency component and high-frequency component of the signal.

In Equation (1) and (3), the low-frequency components of the distortion due to the track error of the satellite radar interference and the distorted phase due to the ionosphere appear at the same time as low-frequency waves, and they are spatially random signals It can not be separated. Therefore, the model generation unit 150 of the present invention generates a model capable of simultaneously calculating the two components (that is, the low frequency component of the distortion phase due to the track error and the distortion phase due to the ionosphere of the satellite radar interference degree) Can be generated using a difference polynomial model. That is, the two-dimensional polynomial model applied to each of the satellite radar interference and the filtered MAI interference so as to simultaneously model the two components is expressed by the following equations (5) and (6).

[Formula 5]

Equation (5) is a model simultaneously considering a distortion component due to the track error of the satellite radar interference degree and a low-frequency component of the distortion phase due to the ion layer, where a ₀ , a _{1, ... ,} a ₆ is the model parameter, and h (x, r) is the height value at the (x, r) image position. In this case, the phase difference of the satellite radar interference according to the flight direction calculated by the flight direction phase difference calculation unit 130 is considered in h (x, r). In the present invention, by using h (x, r) It is possible to reduce the atmospheric effect caused by the air.

[Formula 6]

Equation (6) is a model simultaneously considering a distortion component due to the trajectory error of the filtered MAI interference degree and a low-frequency component of the distortion phase due to the ion layer, where b ₀ , b _{1, ... ,} B ₃ is a model parameter, h (x, r) is (x, r) means the height value at the image position, the h (x, r) is g (interferogram as forward-looking and backward-looking interface And the error due to the matching difference of the first and second embodiments can be reduced.

Next, the integrated MAI interference degree acquisition section 160 obtains the integrated MAI interference degree by integrating the filtered MAI interference degree, and obtains the distortion phase value by the ion layer of the satellite radar interference degree from the integrated MAI interference degree And the distortion phase value due to the orbit error can be calculated. Hereinafter, a calculation process by the integrated MAI interference level acquisition unit 160 will be described.

The integrated MAI interference level acquisition unit 160 first transforms the following equation (7) into the following equation (8).

[Equation 7]

)이 비행방향의 변위(

)와 선형 관계가 있음을 나타낸 것으로서, 여기서

는 위성레이더의 파장을 나타내고,

는 위성레이더 시스템과 촬영 기하에 따라 달라지는 파라미터를 나타내며, 비행방향의 변위(

)는 필터링된 MAI 간섭도의 위상 값으로부터 계산이 가능하다. 이에 따라 적분된 MAI 간섭도 획득부(160)는 식 7을 식 8과 같이 변형할 수 있다.Equation (7) shows the differential value of the flight direction when an error is caused by the ionosphere in the satellite radar interference degree (InSAR)

The displacement of this flight direction

), Which indicates that there is a linear relationship with

Represents the wavelength of the satellite radar,

Indicates the parameters that depend on the satellite radar system and the imaging geometry, and the displacement in the flight direction (

) Can be calculated from the phase value of the filtered MAI interference figure. Accordingly, the integrated MAI interference level acquisition unit 160 can transform Equation (7) into Equation (8).

[Equation 8]

At this time, since the amount of distortion due to the ion layer can be divided into a low frequency component and a high frequency component, the integrated MAI interference level acquisition unit 160 can transform Equation 8 into Equation (9).

[Equation 9]

Next, the integrated MAI interference level acquisition unit 160 can transform Equation (9) into Equation (10) using Equations (1) to (4).

[Equation 10]

In this case, the distortion phase due to the surface displacement of the satellite radar interference degree in Equation 1, the distortion phase due to the atmosphere, and the distortion phase due to the surface displacement of the MAI interference degree in Equation 2 are small noise and masking masking), it is not considered in Equation 10.

Next, the integrated MAI interference level acquisition unit 160 can derive Equation (11) by substituting Equation (5) and Equation (6) into Equation (10).

[Equation 11]

Expression 12 and Expression 13 are as follows.

[Equation 12]

[Formula 13]

는 모델 파라미터를 나타내며, 적분된 MAI 간섭도 획득부(160)는 식 12 및 식 13에서 필터링된 MAI 간섭도를 적분함으로써 획득한 적분된 MAI 간섭도로부터 위성레이더 간섭도의 이온층에 의한 왜곡 위상 값과 궤도 오차에 의한 왜곡 위상 값을 계산할 수 있다. 적분된 MAI 간섭도는 식 12와 식 13을 식 14와 같이 변형함으로써 획득할 수 있다.here,

And the integrated MAI interference degree acquisition section 160 calculates the distortion phase value due to the ion layer of the satellite radar interference degree from the integrated MAI interference map obtained by integrating the filtered MAI interference maps in Equations 12 and 13 And the distortion phase value due to the orbit error can be calculated. The integrated MAI interference figure can be obtained by modifying Equation (12) and Equation (13) as Equation (14).

[Equation 14]

In this case, the model parameters in Equation 13 can be calculated through polynomial estimation, and if Equation 14 is solved using the estimated model parameters, the distortion phase value due to the ion layer of the satellite radar interference degree and the distortion phase value due to the orbital error are expressed by Equation 15 can be expressed as follows.

[Formula 15]

Here, C (x, r) denotes an integral constant, which includes a distortion component due to an orbit error. And the integral constant can be defined as shown in Equation 16 below.

[Formula 16]

Here, C ₀ , C _{1, ... ,} C ₄ represents the model parameter, and C ₀ and C ₁ represent functions according to the range position change. In addition, the C ₀ and C ₁ are used to reduce the integration error of the orientation caused by the noise of the filtered MAI interference degree (azimuth) direction, at the other model parameters _{(C 2, C 3, C} 4) Is used to eliminate the orbit error of satellite radar interference. It can be seen that the present invention considers both azimuth direction and range direction positions unlike the conventional method.

More specifically, in the case of the conventional method, since the integration constant according to the distance position is estimated from the difference value between the MAI interference and the satellite radar interference, a discontinuity occurs when the correlation difference between adjacent pixels in the azimuth direction is large there was. On the other hand, according to the present invention, the integration constant determined by the integrated MAI interference level acquisition unit 160 is estimated in consideration of both the azimuth direction and the distance direction based on the multiple regression equation, thereby obtaining an integration constant having no discontinuity There is a feature that can be estimated.

Next, the corrected satellite radar interference level acquisition unit 170 acquires the integrated MAI interference level obtained through the MAI interference level acquisition unit 160 integrated in the satellite radar interference level produced by the satellite radar interference level production unit 110 That is, the integrated MAI interference figure including the distortion phase value due to the ion layer of the satellite radar interference degree and the distortion phase value due to the orbital error), thereby obtaining the corrected satellite radar interference degree. Hereinafter, the corrected satellite radar interference level obtaining unit 170 may obtain the corrected satellite radar interference level through the following procedure.

For example, if the size of the satellite radar interference is N pixels in the azimuth direction and M pixels in the direction of the distance, C ₀ (a), ... , C ₀ (M), C ₁ (1), ... , C ₁ (M), C ₂ , C ₃ , and C ₄ . At this time, the corrected satellite radar interference degree obtaining unit 170 may construct a matrix as shown in Equation 17 to use a multiple regression equation.

[Formula 17]

는 (M·N)의 벡터로서 식 20과 같이 정의할 수 있다.Here, A can be defined as a planning matrix as (18) as (M · N) × (2M + 3) and c can be defined as a (2M + 3) vector parameter as shown in equation

Can be defined as the expression (20) as a vector of (M · N).

[Formula 18]

[Formula 19]

[Formula 20]

은

이고,

는

가 된다.here,

silver

ego,

The

.

Accordingly, the corrected satellite radar interference level acquisition unit 170 can define the corrected satellite radar interference level as shown in Equation (21).

[Formula 21]

)에서 적분된 MAI 간섭도 획득부(160)를 통하여 획득한 적분된 MAI 간섭도(

)를 제거함으로써, 위성레이더 간섭도에서 이온층에 의한 왜곡 위상 값과 궤도 오차에 의한 왜곡 위상 값이 보정된 보정 위성레이더 간섭도(

)를 획득할 수 있다.That is, according to Equation (21), the corrected satellite radar interference level acquisition section 170 acquires the satellite radar interference level (

The integrated MAI interference degree obtained through the integrated MAI interference degree acquisition unit 160

The corrected satellite radar interference figure in which the distortion phase value due to the ion layer and the distortion phase value due to the orbital error are corrected in the satellite radar interference degree

Can be obtained.

The apparatus for correcting ion distortion 100 based on the multi-interference technique according to an embodiment of the present invention has the following advantages. First, the ion distortion correcting apparatus 100 of the present invention can eliminate the phase error due to the satellite orbit generated when applying the conventional technique by simultaneously calculating the satellite orbital error component and the error component due to the ionospheric phase distortion, Images can be acquired. Second, the ion distortion correction apparatus 100 of the present invention applies a direction filter to an area where masking of a flight direction displacement occurring locally or an area where interference generation is not possible, such as a wide area, a lake, By doing this, we can apply the technique to more diverse regions. Finally, the ion distortion correction apparatus 100 of the present invention estimates an integral constant having no discontinuous points by considering both the azimuth direction and the position in the distance direction based on the multiple regression equation, Which can solve the discontinuity that can be shown.

Hereinafter, the operation flow diagram of the present invention will be described in detail based on the contents described above in detail.

FIG. 2 is a flowchart illustrating a method for correcting ion distortion based on a multi-interference technique according to an embodiment of the present invention.

Referring to FIG. 2, an ion distortion correction apparatus 100 based on a multi-interference technique according to an embodiment of the present invention firstly uses a SAR (Synthetic Aperture Radar) image by a flight direction phase difference calculation unit 130 A differential value with respect to the flight direction is calculated from the satellite radar interference degree produced (S210).

At this time, in step S210, the satellite radar interference figure production unit 110 may generate the satellite radar interference figure, and the satellite radar interference figure production unit 110 generates the front observation radar interference figure And the rear observation radar interference figure can be produced through the rear observation radar interference figure production part 112. [

SAR (Synthetic Aperture Radar) image is a high resolution radar image produced by shooting a microwave from a sensor, capturing a target thousands of times and compressing it. SAR images are made up of complex numbers with magnitude and phase, the size means the reflectivity of the surface, and the phase means that it is expressed in one cycle of a sine or cosine curve. The satellite radar interference degree is data prepared from the phase difference of the SAR image by observing the SAR image twice. The method of producing such a satellite radar interference degree is well known in the field of the present invention, and will not be described below.

Accordingly, the front observation radar interference figure production unit 111 produces a front observation SAR image by compressing only the number of times observed from the front of the center of the beam among the number of times the SAR sensor has photographed one target, And the rear observation radar interference figure production unit 112 is fabricated in the same manner as the production of the front observation radar interference figure, A rear observation SAR image is produced by compressing only the number observed from the rear of the center of the beam during the number of times the target is photographed and the rear observation radar interference degree is calculated from the phase difference calculated by observing the rearward observation SAR image twice And make them.

Thereafter, the flight direction phase difference calculation unit 130 calculates the derivative value with respect to the flight direction from the satellite radar interference figure produced by the satellite radar interference figure production unit 110. [ That is, in step S210, the flight direction phase difference calculation unit 130 calculates the phase difference of the satellite radar interference degree in accordance with the flight direction. At this time, the azimuth direction and the range direction are used in the SAR image, The phase difference of the satellite radar interference degree according to the flying direction can be calculated. A more detailed description will be given with reference to the description of FIG.

Next, the ion distortion correction apparatus 100 according to the present invention is applied to the ion distortion correction apparatus 100 through the filtered MIA interference degree acquisition unit 140, The MAI interference degree is obtained (S220).

At this time, in step S220, the MIA interference figure can be produced by the MIA interference figure production unit 120, and the MAI interference figure production unit 120 can detect the front observation radar interference produced by the front observation radar interference figure production unit 111, The MAI interference figure is produced by calculating the phase difference of the rear observation radar interference degree produced by the radar interference degree production section 1120. The MAI interference degree is used to observe the surface displacement in the flight direction or the velocity of the object. The method of making the MAI interference degree is described in detail in Korean Patent No. 10-1111689, A description thereof will be omitted.

In step S220, the filtered MIA interference level acquisition unit 140 may mask the surface displacement distortion phase and the atmospheric distortion phase included in the MAI interference level.

In step S220, the filtered MIA interference level acquisition unit 140 masks an area having a low degree of coherence or an area having a large displacement locally in the MAI interference map, To obtain the filtered MAI interference figure.

Next, the ion distortion correction apparatus 100 of the present invention includes an ion distortion phase and an orbital distortion phase through the model generation unit 150 based on the differential value for the flight direction and the filtered MAI interference level (S230).

At this time, in step S230, the model generating unit 150 may generate the model including the ion distortion phase and the orbital distortion phase using the second-order polynomial model, and the model including the ion distortion phase and the orbital distortion phase Model may be generated for each of the satellite radar interference and the filtered MAI interference.

Next, the ion distortion correcting apparatus 100 of the present invention integrates the filtered MAI interference map based on the generated model by the integrated MAI interference map obtaining unit 160 to obtain the integrated MAI interference map (S240).

At this time, the MAI interference degree acquisition unit 160 integrated in step S240 estimates the integration constant included in the integrated MAI interference degree in consideration of the azimuth direction and the range direction based on the multiple regression equation Wherein the integration constant reduces the integration error in the azimuth direction due to the noise of the filtered MAI interference degree and removes the orbital distortion phase of the satellite radar interference degree.

The integrated MAI interference level acquisition unit 160 may calculate the value of the ion distortion phase and the value of the orbital distortion phase included in the satellite radar interference level through the integrated MAI interference level.

Next, the ion distortion correction apparatus 100 of the present invention calculates the corrected satellite radar interference degree by removing the integrated MAI interference degree in the satellite radar interference degree through the corrected satellite radar interference degree obtaining section 170 (S250).

That is, in step S250, the corrected satellite radar interference level acquisition unit 170 acquires the integrated MAI interference obtained through the MAI interference level acquisition unit 160 integrated in the satellite radar interference level produced by the satellite radar interference level production unit 110 (I. E., The integrated MAI interference figure including the distortion phase value due to the ion layer of the satellite radar interference degree and the distortion phase value due to the orbital error).

The present invention can acquire a better quality radar image for an image including an area where interference can not be generated, such as sea and lake, and simultaneously calculates an error component due to satellite orbit error and ion layer phase distortion, , It is possible to acquire radar images with higher accuracy and usability. Further, in the process of determining the integral constant, the present invention can compensate for the disadvantage that discontinuity may appear for the adjacent pixels in the flight direction by simultaneously considering the viewing direction and the flying direction.

In addition, the present invention reduces errors by establishing a model including satellite orbit error and ion layer distortion error, and makes it possible to correct ionospheric distortion even in an image including an area where interference can not be generated by using a direction filter, It is possible to apply the ion distortion correction to more various regions within the region.

Hereinafter, an ion distortion correction method based on a multi-interference technique according to an embodiment of the present invention and experimental results performed to verify effects of the ion distortion correction method will be described in detail.

In this experiment, we used the ALOS (Advanced Land Observing Satellite Array) type L-band Synthetic Aperture Radar (ALOS) data obtained on June 22, 2009 and June 25, And the results were verified. Table 1 below shows the characteristics of the ALOS PALSAR image used in the experiment to apply the ion distortion correction method based on the multi-interference technique proposed in the present invention. Two images (ie, master and slave images) obtained from the ascending orbit of the satellite were taken at a time interval of about one year, and the vertical base line distance is about -700 m.

Master Slave B _T
(Days) B _⊥
(m) f _{DC, f}
(Hz) f _{DC, c}
(Hz) f _{DC, b}
(Hz) June 22, 2008 June 25, 2009 368 -699.9 432.48 31.43 -373.85

Where B _T means the time base line between the master and slave SAR pairs, B _⊥ means the vertical baseline between the master and slave SAR pairs, f _{DC, f} , f _{DC, c} And f _{DC, b} mean forward, averaged and rearward Doppler centers.

FIG. 3 is a view showing a data acquisition area and a coherence map of ALOS PALSAR according to one embodiment of the present invention. The satellite radar interference distortion caused by the ionosphere occurs mainly in polar regions, equatorial regions, or large fault zones. However, in Korea, which is in the mid - latitude region due to solar activity, radar interference errors are sometimes caused by the ionosphere. In the study area of the experiment, the intensities are more than 0.4 in urban areas such as Seoul and Incheon, but the other areas are relatively less intact. The low degree of tightness causes the increase of the noise of the interference degree. Moreover, since there are many regions adjacent to the sea in Korea, it is difficult to directly apply the existing MAI based ionospheric correction technique.

Therefore, the present invention generates satellite radar interference and MAI interference in order to check the distortion of the interference caused by the ionosphere using ALOS PALSAR data. At this time, the satellite radar interference level is generated by the satellite radar interference level production unit 110 of the ion distortion correction apparatus 100 of the present invention, and the MAI interference level can be generated by the MAI interference level production unit 120.

At this time, the satellite radar interference level production unit 110 adjusts the satellite radar interference level to 5 in the view direction in order to increase the tightness of the spatial resolution of the view direction and the flight direction in the initially generated SLA (Single Look Complex) And 20 lines of multi - look processing in the flight direction. Accordingly, the pixel size of the satellite radar interference degree is about 45 m × 60 m in both the viewing direction and the flying direction, and the MAI interference level is also subjected to the same multi-look processing by the MAI interference level producing unit 120. In order to correct the phase effect due to the terrain of the satellite radar interference degree, the ion distortion correction apparatus 100 of the present invention uses the SRTM DEM (Shuttle Radar Topography Mission Digital Elevation Model) In order to improve the tightness of the satellite radar interference, the Goldstein filter was applied and then the MCF (Minimum Cost Flow) algorithm was used to perform phase unwrapping.

The MAI interference generator 120 generates two SCL images using a different Doppler center frequency from a pair of ALOS PALSAR RAW data to generate the MAI interference, and the forward-looking SLC and the backward-looking It was generated from Doppler center frequency of SLC using flight direction distance bandwidth of 798.9 Hz by common directional band filtering. After performing multi-look from each forward-looking SLC and backward-looking SLC image, Forward and Backward interference maps are generated, and MAI interference maps are generated with flat-earth and topological phase removed. At this time, the MAI interference also applies the Goldstein filter and the MCF algorithm as well as the satellite radar interference.

4 is a diagram illustrating a satellite radar interference map, a MAI interference map, and a filtered MAI interference map generated according to an embodiment of the present invention. 4 (a) can be obtained by the satellite radar interference plot 110, FIG. 4 (b) can be obtained by the MAI interference plot 120, and FIG. 4 (c) Filter can be obtained by the filtered MAI interference acquisition section 140. [

As shown in FIG. 4 (a), when the phase changes according to the flight direction, it is generally possible to estimate an error due to a large-scale fault zone or a satellite orbit. However, in the case of the present study, Because there is no area, it is impossible to guess by satellite orbit error. However, in the MAI interference diagram of FIG. 4 (b), the streaking phenomenon appears in the direction of the image from the entire image in the direction similar to the satellite radar interference, and the phase is changed. This phenomenon has been reported as a phase error pattern by a typical ionosphere. In order to obtain higher quality satellite radar interference, it is necessary to correct the satellite radar interference degree for this phenomenon.

Since SAR images used in this experiment include the West Sea region, there are areas where interference can not be generated. For this reason, the conventional MAI-based ionospheric phase-distortion correction scheme can not be applied directly. Thus, the filtered MAI-interference-point obtaining unit 140 of the present invention applies the directional filter to the MAI- , The interpolated MAI is generated as shown in FIG. 4 (c).

At this time, when a specific pattern is seen in a diagonal direction (or a vertical direction or a horizontal direction) as shown in FIG. 4 (b), the direction filter holds a pixel in a range (horizontal direction) and holds a pixel in azimuth (I.e., holding a pixel in a rectangular shape) to perform interpolation, i.e., performing interpolation while maintaining the pattern. For example, in the upper left corner of FIG. 4 (b), the Null value is empty in the sea area, and such an empty value has a great influence on the integration. Thus, the present invention performs a directional filter on the empty value as described above , As shown in Fig. 4 (c), it is possible to generate a value of the same pattern for a portion having no value. Further, in the present invention, by applying the direction filter, various noises are reduced.

FIG. 5 is a graph showing the relationship between the flight direction differential image of the satellite radar interference diagram (InSAR) generated according to an embodiment of the present invention, the image including the ionic layer distortion phase and the orbital distortion phase, and the orbital distortion phase image using the second- Fig.

That is, FIG. 5 (a) is an image obtained by the flight direction phase difference calculation unit 130 of the present invention, and the satellite direction radar interference degree (that is, FIG. And a derivative value was generated. 6 (b) is an image obtained by the integrated MAI interference degree obtaining section 160 of the present invention, which can be obtained by calculating a correction value including an ion phase distortion error and an orbital phase error from Equation 14 have. 6 (c) is an image obtained by the integrated MAI interference level acquisition unit 160, which can be obtained by calculating a satellite orbit error based on the two-dimensional polynomial correction method and using Equation 15 have.

FIG. 6 is a diagram showing an interferogram image of a satellite radar interference diagram (InSAR) generated according to an embodiment of the present invention, and an interferogram image of InSAR generated by correcting only the orbital distortion phase.

6 (a) shows the corrected satellite radar interference degree obtained by the corrected satellite radar interference degree obtaining section 170 of the present invention, which is derived by considering the phase distortion error value and the orbital phase error value by the ion layer Lt; / RTI > 6 (b) shows the corrected satellite radar interference level generated using only the orbit error value calculated by the polynomial fitting method.

In this case, in the case of the image corrected by considering both the phase distortion error value by the ion layer and the orbital phase error value (i.e., FIG. 6 (a)), no particular pattern was observed in the satellite radar interference full image, 6 (b), it can be seen that the stripe pattern remains in the flight direction in the entire region of the interference degree. In the case where only the orbital error is corrected, the satellite radar interference Therefore, the ion interference correction method based on the multi-interference technique proposed in the present invention performs correction by considering both the distortion phase due to the ion layer and the distortion phase due to the orbit error , It is possible to correct ion distortion of satellite radar interference with better quality.

FIG. 7 is a view showing a profile value distribution in a flight direction for analyzing a correction effect of a phase error by an ion layer according to an embodiment of the present invention. FIG. This shows a distribution diagram for the section A-A 'shown in Fig. 6 (a).

Referring to FIG. 7, in order to analyze a phase change pattern, an average value is displayed every 100 pixels in a direction of a range along the direction of the flight direction by 10 pixels.

)은 약 -2.5 rad~1 rad 사이에 분포되어 있으며, 저주파 sin 형태의 패턴이 확인되었다. 이러한 결과는 이온층에 의한 위상 왜곡이 저주파 형태로 나타나며, 이와 같은 형태로 발생하는 궤도 오차는 분리할 수 없음을 의미한다. 그리고, 다항식 접합(polynomial fitting)을 이용하여 위성레이더 간섭도에서 궤도 오차만을 수행한 경우(

)에는 위상 분포 범위가 조금 줄어든 정도에 불과함을 확인할 수 있다.The phase of the initial satellite radar interference figure

) Was distributed between about -2.5 rad and 1 rad, and a pattern of a low frequency sin pattern was confirmed. These results indicate that the phase distortion due to the ionosphere is in the form of low frequency, and that the orbit error occurring in this form can not be separated. And, in case of using only polynomial fitting, orbit error in satellite radar interference

), The phase distribution range is only slightly reduced.

)에는 위상의 변화 범위가 ±1 rad으로 비교적 안정되어 있으며, 저주파 sin 형태의 패턴이 없어졌음을 확인할 수 있다. 이는 초기 레이더 간섭도에서 발생하는 저주파 형태의 오차 보정이 효과적으로 되었음을 의미하며, 궤도 오차만을 이용한 간섭도 보정 기법에 비하여 더욱 향상된 결과를 획득할 수 있었다.On the other hand, when the satellite radar interference is corrected by considering the ion distortion error and the orbit error using the technique of the present invention

), The phase change range is relatively stable at ± 1 rad, and it can be confirmed that the low-frequency sin-like pattern is eliminated. This means that the low - frequency error correction that occurred in the initial radar interference is effective, and the improved results can be obtained compared to the interference correction method using only the orbit error.

In conclusion, there is a growing interest in satellite radar interferometry as a method for surface monitoring. Especially, the radar interference technique using the long wavelength band like L-band keeps a relatively high degree of tightness compared with the acquisition time difference between two images, and thus its utilization is attracting attention. However, satellite radar images contain phase errors due to the ionosphere, and they are proportional to the wavelength length. Therefore, SAR images using long wavelengths are characterized in that the errors in the satellite radar interference degree are rapidly increased. Do.

Accordingly, the present invention uses a directional filter so that interference can be generated in an area where interference can not be generated. In the experiment, satellite radar interference and MAI interference were generated from the L-band ALOS PALSAR interference pair obtained in June 2008 and June 2009. As a result, in the satellite radar interference map, In the MAI interference diagram, we confirmed that the streaking effect in the flight direction causes the phase distortion effect by the ion layer. In addition, since the image used in this experiment includes the West Sea region where interference can not be generated, interpolated MAI interference, ie filtered MAI interference, is applied using a directional filter.

Also, when the orbital error correction was performed using the two-dimensional polynomial correction technique, the phase change in the flight direction was similar to the initial radar interference distribution, and the low frequency sin pattern remained unchanged. On the other hand, in the case of applying the method of the present invention, a stable phase change value between ± 1 rad was calculated, and it was confirmed that a specific pattern was lost in the entire image.

ALOS PALSAR, which is currently in operation, and ALOS PALSAR-2, which is currently in operation, as well as SAOCOM and MapSAR, which are expected to be launched soon, are very attracting attention to long-wavelength SAR satellites, Therefore, a correction method for this is indispensably required. Accordingly, the method and apparatus for correcting ion distortion based on the multi-interference technique proposed by the present invention can increase the accuracy of the satellite radar interference degree and thus can be widely used.

The ion distortion correction method based on the multi-interference technique according to an exemplary embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims. They should not be understood individually.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

100: Ion distortion correction device based on multi-interference technique
110: satellite radar interference diagram production part 120: MAI interference diagram production part
130: flight direction phase difference calculation unit 140: filtered MAI interference degree acquisition unit
150: model generation unit 160: integrated MAI interference degree acquisition unit
170: corrected satellite radar interference degree obtaining section

Claims (21)

A flight direction phase difference calculation unit for calculating a differential value with respect to a flight direction from a satellite radar interference figure produced using a SAR (Synthetic Aperture Radar) image;
A filtered MAI interference level acquisition unit for obtaining a filtered MAI interference level using a multiple aperture interferometry (MAI) interference degree produced using the satellite radar interference level;
A model generating unit for generating a model including an ion distortion phase and an orbital distortion phase based on the differential value for the flight direction and the filtered MAI interference level;
An integrated MAI interference level acquisition unit for integrating the filtered MAI interference level based on the generated model to obtain an integrated MAI interference level; And
A corrected satellite radar interference level acquiring unit for deriving the corrected satellite radar interference level by removing the integrated MAI interference level in the satellite radar interference level;
And an ion distortion correction unit based on a multi-interference technique. The method according to claim 1,
The integrated MAI interference degree obtaining unit
Estimating an integration constant included in the integrated MAI interference degree in consideration of an azimuth direction and a range direction based on a multiple regression equation and estimating an integration constant based on a noise of the filtered MAI interference degree through the integration constant; Reducing the integration error in the azimuth direction and removing the orbital distortion phase of the satellite radar interference degree
Wherein the ion distortion correction device is based on a multi-interference technique. The method according to claim 1,
The integrated MAI interference degree obtaining unit
Calculating a value of an ion distortion phase and an orbital distortion phase included in the satellite radar interference degree through the integrated MAI interference diagram
Wherein the ion distortion correction device is based on a multi-interference technique. The method according to claim 1,
The model generation unit
Generating the model including the ionic distortion phase and the orbital distortion phase using a quadratic polynomial model
Wherein the ion distortion correction device is based on a multi-interference technique. The method according to claim 1,
The model generation unit
Generating a model including the ion distortion phase and the orbital distortion phase for each of the satellite radar interference and the filtered MAI interference,
Wherein the ion distortion correction device is based on a multi-interference technique. The method according to claim 1,
The flight direction phase difference calculation unit
Calculating a phase difference of the satellite radar interference degree along the flight direction using an azimuth direction and a range direction in the SAR image
Wherein the ion distortion correction device is based on a multi-interference technique. The method according to claim 1,
The filtered MAI interference degree obtaining unit
Masking and removing the surface displacement distortion phase and the atmospheric distortion phase included in the satellite radar interference diagram and the surface displacement distortion phase included in the MAI interference diagram
Wherein the ion distortion correction device is based on a multi-interference technique. The method according to claim 1,
The filtered MAI interference degree obtaining unit
Masking a region having a low coherence or a region having a large displacement locally in the MAI interference degree to obtain the filtered MAI interference degree by applying a directional filter
Wherein the ion distortion correction device is based on a multi-interference technique. The method according to claim 1,
The filtered MAI interference degree obtaining unit
Using the MAI interference degree produced by using the phase difference between the front observation radar interference and the rear observation radar interference of the satellite radar interference degree
Wherein the ion distortion correction device is based on a multi-interference technique. 10. The method of claim 9,
The filtered MAI interference degree obtaining unit
A forward observation SAR image is produced by compressing only the number of times observed from the front of the center of the beam among the number of times the SAR sensor has photographed the first target and a forward observation SAR image is generated by observing the forward observation SAR image twice, Wherein the backward SAR image is generated by compressing only the number of times of interference and the number of times the SAR sensor has photographed the first target from the rear of the center of the beam to produce a rearward SAR image, Using the MAI interference figure produced based on the produced rear observation radar interference figure
Wherein the ion distortion correction device is based on a multi-interference technique. Calculating differential values for the flight direction from the satellite radar interference map produced using a SAR (Synthetic Aperture Radar) image;
Obtaining a filtered MAI interference level using a multiple aperture interferometry (MAI) interference degree produced using the satellite radar interference degree;
Generating a model including an ion distortion phase and an orbital distortion phase based on the differential value for the flight direction and the filtered MAI interference level;
Acquiring an integrated MAI interference level by integrating the filtered MAI interference level based on the generated model; And
Obtaining the corrected satellite radar interference figure by removing the integrated MAI interference map in the satellite radar interference map;
A method of ion distortion correction based on a multi-interference technique. 12. The method of claim 11,
The step of obtaining the integrated MAI interference figure
Estimating an integral constant included in the integrated MAI interference degree in consideration of an azimuth direction and a range direction based on a multiple regression equation;
Lt; / RTI >
Reducing the integration error in the azimuth direction due to the noise of the filtered MAI interference degree through the integration constant and removing the orbital distortion phase of the satellite radar interference degree
Wherein the ionic distortion correction method is based on a multi-interference technique. 12. The method of claim 11,
The step of obtaining the integrated MAI interference figure
Calculating a value of an ion distortion phase and an orbital distortion phase included in the satellite radar interference degree through the integrated MAI interference diagram
Wherein the ionic distortion correction method is based on a multi-interference technique. 12. The method of claim 11,
The step of generating the model
Generating the model including the ionic distortion phase and the orbital distortion phase using a quadratic polynomial model
Wherein the ionic distortion correction method is based on a multi-interference technique. 12. The method of claim 11,
The step of generating the model
Generating a model including the ion distortion phase and the orbital distortion phase for each of the satellite radar interference and the filtered MAI interference,
Wherein the ionic distortion correction method is based on a multi-interference technique. 12. The method of claim 11,
The step of calculating a derivative value for the flight direction
Calculating a phase difference of the satellite radar interference degree along the flight direction using an azimuth direction and a range direction in the SAR image
Wherein the ionic distortion correction method is based on a multi-interference technique. 12. The method of claim 11,
The step of obtaining the filtered MAI interference figure
Masking and removing the surface displacement distortion phase and the atmospheric distortion phase included in the satellite radar interference diagram and the surface displacement distortion phase included in the MAI interference diagram
Wherein the ionic distortion correction method is based on a multi-interference technique. 12. The method of claim 11,
The step of obtaining the filtered MAI interference figure
Masking a region having a low coherence or a region having a large displacement locally in the MAI interference degree to obtain the filtered MAI interference degree by applying a directional filter
Wherein the ionic distortion correction method is based on a multi-interference technique. 12. The method of claim 11,
The step of obtaining the filtered MAI interference figure
Using the MAI interference degree produced by using the phase difference between the front observation radar interference and the rear observation radar interference of the satellite radar interference degree
Wherein the ionic distortion correction method is based on a multi-interference technique. 20. The method of claim 19,
The step of obtaining the filtered MAI interference figure
A forward observation SAR image is produced by compressing only the number of times observed from the front of the center of the beam among the number of times the SAR sensor has photographed the first target and a front observation SAR image is generated from the front observation SAR image, ;
A rear observation SAR image is generated by compressing only the number of times that the SAR sensor has photographed the first target from the rear of the center of the beam, and the backward observation SAR image is observed twice from the calculated front- Producing a radar interference figure; And
Producing the MAI interference figure using the front observation radar interference and the rear observation radar interference;
A method of ion distortion correction based on a multi-interference technique. A computer-readable recording medium storing a program for executing the method according to any one of claims 11 to 20.

Images