JP6218207B2 - Synthetic aperture radar system, traveling direction velocity calculation device, and traveling direction velocity estimation method - Google Patents

Description

  The present invention relates to a Synthetic Aperture Radar (SAR) system mounted on a moving platform such as an aircraft, and more specifically, information for accurately calculating a traveling direction velocity of an object observed with a Synthetic Aperture Radar system. It relates to a processing system.

  A system has been developed that uses a synthetic aperture radar system mounted on a satellite, an aircraft, or the like to identify a target as a detection target moving on the ground or the sea, and to estimate a moving speed, together with image formation.

Such a technique is described in Patent Document 1 and Patent Document 2, for example.
In the synthetic aperture radar system disclosed in Patent Document 1, the speed and direction of a moving target are estimated in addition to a still state image. When estimating the speed and direction of the target, a shift amount (movement amount) of the target in the image at two different time points is identified, and processing for obtaining the speed and direction from the information is performed. Note that this document also describes the configuration of a synthetic aperture radar system, range compression processing, azimuth compression processing, and the like.
In the synthetic aperture radar system described in Patent Document 2, each received signal is acquired and recorded and stored using an aperture antenna that can be divided in the moving direction of the platform, and the stored data is used after range compression in the distance direction. While detecting a moving target, the speed of what is rough accuracy is calculated | required from the distance with an antenna.

  Further, regarding synthetic aperture radar systems, techniques related to Patent Documents 3 to 5 are also disclosed.

JP-A-10-206539 JP 2009-026720 A JP-A-10-148673 JP 2001-004398 A JP 2003-227872 A

  One problem with existing synthetic aperture radar systems is the accuracy of detection of a moving target (target) on the ground or sea, and the accuracy of information on the speed and direction (velocity vector) of the moving target.

  Among these, with respect to the current usage mode, among the velocity components of the movement target, the irradiation direction component of the radio wave from the platform to the movement target such as a car or a ship can be obtained with a certain degree of accuracy. For example, it may be obtained using a known along track interferometry technique.

On the other hand, there is a problem with respect to the extraction accuracy of the component perpendicular to it, that is, the moving direction velocity component of the platform that the moving target has.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a synthetic aperture radar system that can accurately calculate the speed of a moving target in the traveling direction from acquired data.

  It is another object of the present invention to provide a synthetic aperture radar system capable of accurately obtaining a velocity vector of a moving target using the obtained velocity in the traveling direction.

  It is another object of the present invention to provide a synthetic aperture radar system capable of obtaining an accurate moving target image based on the obtained speed in the traveling direction.

The synthetic aperture radar system according to the present invention uses a plurality of processing parameters assuming a platform traveling direction velocity component of a target to convert amplitude image data for each processing parameter into SAR image reproduction processing and amplitude conversion processing for each processing parameter. The target position information is received, the target position information is referenced, the amplitude image data near the target for each generated processing parameter is compared, and the reaction occurring in the vicinity of the target is detected. About the peak value of the set of amplitude values with respect to the position in the platform traveling direction The velocity calculation in the traveling direction is performed to consider the platform traveling direction velocity component indicated by the processing parameter of the stronger amplitude image data as the platform traveling direction velocity component of the target. SAR / GMTI processing means Comprising a portion from the acquired data from the antenna, the process velocity of the target, to the platform distance direction velocity component of the target is calculated separately from the platform process velocity component of the target is calculated by the process direction velocity calculating means It is characterized by calculating based on.

A traveling direction velocity calculation apparatus according to the present invention uses a plurality of processing parameters assuming a platform traveling direction velocity component of a target, and converts amplitude image data for each processing parameter into SAR image reproduction processing for each processing parameter. And means for generating by executing amplitude conversion processing, and target position information generated by the SAR / GMTI processing unit is received, the target position information is referred to, and amplitude image data near the target for each generated processing parameter The peak value of the set of amplitude values relative to the position in the platform traveling direction of the reaction that occurs in the vicinity of the target by comparing each other. The amplitude image data of the amplitude image data that is stronger or narrower when there is nothing with a predetermined intensity The platform traveling direction velocity component indicated by the processing parameter is Characterized in that it comprises means for performing platform traveling direction velocity component and considered to processing target.

The traveling direction velocity estimation method according to the present invention uses a plurality of processing parameters assuming a target platform traveling direction velocity component, and converts amplitude image data for each processing parameter into SAR image reproduction processing for each processing parameter. Generated by executing the amplitude conversion process, receiving the target position information, referring to the target position information, and comparing the amplitude image data in the vicinity of the target for each generated processing parameter to generate in the vicinity of the target. The peak value of the set of amplitude values relative to the position of the platform direction of the response of the response is the velocity component of the platform direction indicated by the processing parameter of the amplitude image data, which is stronger or narrower when there is nothing with a predetermined intensity. Progress of the target platform Run incorporate direction velocity component regarded be processed SAR / GMTI treatment, this is characterized in that to calculate the platform traveling direction velocity component of the target.

ADVANTAGE OF THE INVENTION According to this invention, the synthetic aperture radar system which can calculate the platform advancing direction speed component of a moving target from acquisition data with high definition can be provided.

In addition, it is possible to provide a synthetic aperture radar system that can accurately determine the velocity vector of the moving target using the platform moving direction velocity component of the determined moving target.

In addition, it is possible to provide a synthetic aperture radar system that can obtain an accurate moving target image based on the platform moving direction velocity component of the moving target thus obtained.

It is a block diagram which shows the apparatus structure of the synthetic aperture radar system of one form of the actual form of this invention. It is a block diagram which shows the apparatus structure of the SAR / GMTI process part of one form of the actual field. It is a block diagram which shows the apparatus structure of the advancing direction speed calculation part of one form of the actual field. It is a schematic diagram which shows the state which the aircraft which is a platform is detecting the ground target which is a movement target. It is explanatory drawing explaining the amplitude image data which concern on the target detected by each target amplitude detection part. It is explanatory drawing which illustrates the threshold value used for the amplitude image data which concerns on a target. It is explanatory drawing which illustrates the speed calculation concept from the several amplitude image data which concern on a target. It is a block diagram which shows the apparatus structure of the SAR / GMTI process part containing the input parameter conversion part of 2nd Embodiment. It is a block diagram which shows the apparatus structure of the advancing direction speed calculation part containing the drawing correction part of 3rd Embodiment. It is a block diagram which shows the apparatus structure of the drawing correction | amendment part of 3rd Embodiment.

[First Embodiment]
An embodiment of the present invention will be described with reference to FIGS.

[Description of configuration]
First, as shown in FIG. 1, the synthetic aperture radar system 1 of this embodiment includes a plurality of antennas (antenna unit 2 and antenna unit 3) and is mounted on a moving platform. A transmitting / receiving unit 4 and a signal processing unit 6 are connected to the antenna unit 2 in order. In addition, a receiving unit 5 and a signal processing unit 7 are connected to the antenna unit 3 in order.

  A SAR / GMTI processing unit 8 that is a signal processing device is connected to the signal processing unit 6 and the signal processing unit 7. The SAR / GMTI processing unit 8 includes a flight information detection unit 9 which is a movement information detection means for detecting the movement speed of the platform, a display / recording unit 10, and various parameters for obtaining the traveling direction speed of the target. A parameter input unit 11 for input is connected.

The SAR / GMTI processing unit 8 is provided with a traveling direction velocity calculation unit 24, and outputs the output data 108 of the flight information detection unit 9 with respect to the output signal 106 of the signal processing unit 6 and the output signal 106 of the signal processing unit 7. In addition to executing image processing similar to that of the existing synthetic aperture radar system, the moving target detection processing and the traveling speed of the target are calculated.
As shown in FIG. 2, the SAR / GMTI processing unit 8 includes a SAR image reproduction processing unit 21, and the signal processing unit 6 and the flight information detection unit 9 are connected as inputs. The output of the SAR image reproduction processing unit 21 is connected to the moving target detection / distance direction speed calculation unit 23 and the image generation unit 26, and the complex image data 201 reproduced from the signal processing unit output signal 106 from the signal processing unit 6 is obtained. Output.

  The SAR / GMTI processing unit 8 includes a SAR image reproduction processing unit 22, and the signal processing unit 7 and the flight information detection unit 9 are connected as inputs. The output of the SAR image reproduction processing unit 22 is connected to the movement target detection and distance direction velocity calculation unit 23 and outputs complex image data 202 reproduced from the signal processing unit output signal 107 from the signal processing unit 7.

  The outputs of the SAR image reproduction processing unit 21 and the SAR image reproduction processing unit 22 are connected to one moving target detection and distance direction speed calculation unit 23. The moving target detection and distance direction speed calculation unit 23 receives inputs from the SAR image reproduction processing units 21 to 22 and the parameter input unit 11, outputs target position information 203 to the traveling direction speed calculation unit 24, and performs speed synthesis. The distance direction speed information 205 is output to the unit 25. Note that as the moving target detection process, a rough traveling direction speed of the target may be obtained.

  The traveling direction speed calculation unit 24 is connected to the signal processing unit 6, the flight information detection unit 9, the parameter input unit 11, the movement target detection and distance direction speed calculation unit 23 as inputs, and to the speed synthesis unit 25 as outputs. Connected, the traveling direction speed information 204 is output to the speed synthesis unit 25.

  The speed compositing unit 25 receives the distance direction speed information 205 from the moving target detection and distance direction speed calculation unit 23 and the travel direction speed information 204 from the travel direction speed calculation unit 24 as inputs, performs a compositing process, and performs target processing. Output as GMTI data 110.

  The image generation unit 26 performs an amplitude conversion process on the complex image data 201 and outputs the result as amplitude image data 109.

Here, the configuration of the traveling direction speed calculation unit 24 will be described in detail.
As shown in FIG. 3, the traveling direction speed calculation unit 24 includes an image reproduction processing parameter calculation unit 31, SAR image reproduction processing units 32-34, image generation units 35-37, target amplitude detection units 38-40, and speed determination. Part 41 is provided. As shown in the figure, three sets of SAR image reproduction processing units 32 to 34, image generation units 35 to 37, and target amplitude detection units 38 to 40 are provided in parallel.

  The image reproduction processing parameter calculation unit 31 is connected to the flight information detection unit 9, the parameter input unit 11, and the three SAR image reproduction processing units 32 to 34, and outputs the flight information detection unit 9 and the parameter input unit 11. The corrected flight information detection unit output data 301 to 303 are output to the respective sets of SAR image reproduction processing units 32 to 34 as input.

The corrected flight information detection unit output data 301 to 303 are respective processing parameters assuming the traveling direction velocity of the target input to each SAR image reproduction processing unit.
Each processing parameter here is an input parameter from the flight information detection unit normally given to the SAR image reproduction processing unit (for example, flight information detection unit output data 108 from the flight information detection unit 9 given to the SAR image reproduction processing unit 21). ), And the image reproduction processing parameter calculation unit 31 converts the reference parameter (assumed target traveling direction speed) input to the parameter input unit 11 and a parameter reflecting its surrounding values.
Here, it is derived whether or not any of the velocities individually reflected in the respective processing parameters is close to the true traveling direction speed of the target by the processing of the speed determining unit 41 described later, and which is closer.

  The SAR image reproduction processing units 32 to 34 receive the corrected flight information detection unit output data and the signal output unit output signal 106 from the signal processing unit 6 as inputs, and input complex image data to the image generation units 35 to 37. Output. The image generation units 35 to 37 have target amplitude detection units 38 to 40 on the respective output sides, generate amplitude image data from the received complex image data, and output the amplitude image data to the target amplitude detection units 38 to 40, respectively. .

  Each of the target amplitude detectors 38 to 40 receives the amplitude image data generated by the image generators 35 to 37 as input, and the target position information 203 from the moving target detection and distance direction speed calculator 23 and the parameter input unit 11. Based on the parameter input unit output data 111 including information such as a threshold value used as an amplitude extraction reference, the amplitude in the vicinity of the target to be compared is extracted, and the target amplitude extraction result information 310 is sent to the speed determination unit 41. ~ 312 are output.

The speed determination unit 41 includes parameter input unit output data 111 including information necessary for determination such as weighting for determining the priority of data acquired on the basis of amplitude extraction from the parameter input unit 11, and a target amplitude detection unit. The target amplitude extraction result information having an element closer to the ideal shape is selected by comparison by receiving inputs from 38 to 40, and the traveling direction speed indicated by the processing parameter of the selected target amplitude extraction result information is determined as the target traveling direction. The speed is recognized and output to the speed synthesizer 25 as traveling direction speed information 204.
Based on the traveling direction velocity of the target obtained by the velocity determining unit 41, the velocity of the target combined with the distance direction velocity can be obtained with high accuracy by the velocity synthesis unit 25.

[Description of operation]
Next, the overall operation of the synthetic aperture radar system 1 will be described with reference to FIG. 4 in addition to FIGS. 1 to 3.
As shown in FIG. 4, the synthetic aperture radar system 1 is mounted on a moving platform 12, and transmits a radar wave to the ground 13 that is a target surface for searching for a target via the antenna unit 2 described above. At the same time, the radar waves reflected by the antenna unit 2 and the antenna unit 3 are received. The synthetic aperture radar system 1 analyzes the received radar wave and searches for the target in parallel with the generation of the image of the target surface to obtain the position, moving direction, and moving speed. At this time, the traveling direction speed is obtained by a processing method not performed in the existing technology, and the moving speed is obtained with high definition. The operation of each part at this time will be described in detail.

As shown in FIG. 1, the transmission / reception unit 4 outputs a transmission wave 101 to the antenna unit 2, receives a reception wave 102, and outputs a video signal 104 to the signal processing unit 6. The signal processing unit 6 performs predetermined signal processing on the received video signal 104 and outputs the signal received by the antenna unit 2 to the SAR / GMTI processing unit 8 as a signal processing unit output signal 106.
The receiving unit 5 receives the received wave 103 from the antenna unit 3 and outputs a video signal 105 to the signal processing unit 7. Similarly to the signal processing unit 6, the signal processing unit 7 performs predetermined signal processing on the received video signal 105, and uses the signal received by the antenna unit 3 as the signal processing unit output signal 107 as the SAR / GMTI processing unit 8. Output to.
The flight information detection unit 9 detects various data related to the movement of the platform 12 and outputs the data as flight information detection unit output data 108 to the SAR / GMTI processing unit 8. For example, the flight information detection unit 9 includes various sensor devices such as aircraft GPS and gyroscopes, and various data related to the movement of the platform 12 includes the position, speed, acceleration, and sway (pitch, roll) , Yaw angle), etc. are output as flight information detector output data 108. These pieces of information may be received from other systems (groups) and used.

  The SAR / GMTI processing unit 8 uses the flight information detection unit output data 108 from the flight information detection unit 9 for the output signals of the signal processing unit 6 and the signal processing unit 7 and is similar to the existing synthetic aperture radar system. While performing image processing, the generation processing of the vector information regarding the movement of the target 14 which is a movement target is performed. At this time, the traveling direction speed information 204 and the distance direction speed information 205 are separately calculated and added together to obtain highly accurate vector information of the target 14.

When this processing is performed, the parameter input unit 11 receives parameter input unit output data 111 for controlling the SAR / GMTI processing unit 8 (traveling direction velocity calculation unit 24).
The parameter input unit 11 may input the target traveling direction speed assumed by the operator using an input device such as a keyboard as an initial parameter, or the system may select and input a speed as an initial parameter. May be. The initial parameter may be input by obtaining a parameter with high accuracy from a target rough velocity vector obtained by an existing method in terms of the system, or may sequentially input a parameter group prepared in advance. Moreover, it is good also as inputting initial parameters, such as a deviation, with the advancing direction estimated speed calculated | required from the speed calculation result of the same target performed last time as an initial value.

  The display / recording unit 10 displays and prints on the screen the amplitude image data 109 and the GMTI data 110 corresponding to the processing results performed by the SAR / GMTI processing unit 8 using a recording device such as a display, a printer, and a hard disk. Then, display and recording of data such as traveling direction speed information 204 and distance direction speed information 205 are executed.

Next, the operation of the SAR / GMTI processing unit 8 will be described in detail. The flow of signals related to the SAR / GMTI processing unit 8 is as shown in FIG.
The SAR image reproduction processing unit 21 and the SAR image reproduction processing unit 22 use the flight information detection unit output data 108 from the flight information detection unit 9 for the output signals from the signal processing unit 6 and the signal processing unit 7. Then, the image reproduction process of the existing synthetic aperture radar is executed, and the complex image data 201 and the complex image data 202 are output to the moving target detection and distance direction velocity calculation unit 23, respectively.
The moving target detection and distance direction speed calculation unit 23 uses the flight information detection unit output data 108 for the complex image data 201 and the complex image data 202 to perform known along track interferometry processing or known DPCA processing. The distance direction speed information 205 indicating the speed in the distance direction of the target 14 is output to the speed synthesis unit 25 and the target position information 203 is output to the traveling direction speed calculation unit 24.
The traveling direction speed calculation unit 24 uses the flight information detection unit output data 108, the parameter input unit output data 111, and the target position information 203 for the output signal from the signal processing unit 6, and the traveling direction of the target 14. Is calculated and output to the speed synthesizer 25 as traveling direction speed information 204.
The image generation unit 26 performs an amplitude conversion process on the complex image data 201 and outputs the result as amplitude image data 109. Specifically, the image generation unit 26 calculates the amplitude R by the calculation “R = sqrt (I ² + Q ² )” where the real part and the imaginary part of the complex image data 201 are I and Q, respectively. And amplitude image data 109 is output.

  The speed synthesizing unit 25 synthesizes the traveling direction speed information 204 that is the output of the traveling direction speed calculating unit 24 and the distance direction speed information 205 that is the output of the moving target detection and distance direction speed calculating unit 23 to perform the processing of the moving target. The speed and direction (speed vector) are obtained, and the result is output as GMTI data 110.

Next, the operation of the traveling direction speed calculation unit 24 will be described in detail. The flow of signals related to the traveling direction velocity calculation unit 24 is as shown in FIG.
The image reproduction processing parameter calculation unit 31 outputs the processing parameters as the corrected flight information detection unit output data 301 using the parameter input unit output data 111 and the flight information detection unit output data 108. Similarly, the corrected flight information detection unit output data 302 and the corrected flight information detection unit output data 303 are output. The corrected flight information detection unit output data 301 to 303 are a plurality of processing parameters using the flight information detection unit output data 108 and assuming the traveling speed of the target.

  In this description, as the processing in the image reproduction processing parameter calculation unit 31, a target traveling direction estimated speed initial value VE and a speed deviation ΔV are received from the parameter input unit output data 111, and a plurality of processing parameters are generated. Even if the speed deviation ΔV is not accepted, for example, three different types of initial parameters are accepted, or the deviation or speed difference is held in advance as a specified value, etc. If a plurality of parameters can be generated, a plurality of processing parameters may be generated by other methods.

Each processing parameter generated by the image reproduction processing parameter calculation unit 31 is a processing parameter obtained by changing the correction to the flight information detection unit output data 108 (processing parameter) used by the SAR image reproduction processing unit 21 for image formation.
For example, when the corrected flight information detection unit output data 301 is set to the target traveling direction estimated speed initial value VE as the initial parameter, the traveling direction estimated speed initial value VE and its deviation ΔV are used to determine the target traveling direction initial value VE. Assuming that the speed is VT1, the parameter value can be determined by the calculation “ VT1 = VE + ΔV”.
Parameter values, the process velocity component VP from the flight information detector output data 108 platform, "VP ← VP + VT1" made by replacing it Ri by the calculation.
Similarly, as the corrected flight information detection unit output data 302, the assumed target traveling direction speed VT2 is obtained by calculation “ VT2 = VE (± 0)”, and the platform progress in the flight information detection unit output data 108 is obtained. A signal in which the direction velocity component VP is similarly replaced is output.
Similarly, as the post-correction flight information detection unit output data 303, the assumed target traveling direction speed VT3 is obtained by the calculation “ VT3 = VE−ΔV”, and the platform traveling direction speed in the flight information detection unit output data 108 is obtained. Output the component VP similarly replaced.

  In this way, a plurality of processing parameters are generated with VT1, VT2, and VT3 as the target traveling direction speeds, respectively, and which of the assumed speeds is closer to the true speed of the target is processed as follows. Obtained from the amplitude image data.

  The SAR image reproduction processing unit 32 uses the post-correction flight information detection unit output data 301 of the image reproduction processing parameter calculation unit 31 for the signal processing unit output signal 106 from the signal processing unit 6, and the existing synthetic aperture. Radar image reproduction processing is performed, and complex image data 304 is output. Similarly, the SAR image reproduction processing unit 33 and the SAR image reproduction processing unit 34 use the corrected flight information detection unit output data 302 and 303 with respect to the signal processing unit output signal 106, and the existing synthetic aperture radar. Image reproduction processing is performed, and complex image data 305 and 306 are output.

  The image generation units 35 to 37 perform amplitude conversion processing on the complex image data 304 to 306, respectively, and output amplitude image data 307 to 309.

  Each of the target amplitude detection units 38 to 40 uses the target position information 203 and the parameter input unit output data 111 to appropriately extract the amplitude portion in the vicinity of the target from the amplitude image data 307 to 309, and target amplitude extraction result information 310 to 312 is output.

  The speed determination unit 41 receives the target amplitude extraction result information 310, the target amplitude extraction result information 311 and the target amplitude extraction result information 312 as input, and an image figure closer to the ideal shape is obtained by the comparison operation. The processing parameter (assumed speed) is calculated as the target traveling speed and output as traveling direction speed information 204.

Here, processing operation examples of the target amplitude detection units 38 to 40 and the speed determination unit 41 will be described.
FIG. 5 is an explanatory diagram for explaining detection of amplitude image data relating to a target by each of the target amplitude detection units 38 to 40. As shown in FIG. 5, the amplitude in each diagram in the vicinity of the position (X, Y) indicated by the target position information 203 from each of the amplitude image data 307 to 309 spreads around the peak and the peak. Data processing is performed based on the viewpoint (the viewpoint for obtaining the ideal shape), and the result is output as the target amplitude extraction results 310 to 312.
At this time, with respect to the desired peak and spread, one or more threshold values may be used to eliminate unnecessary data and to improve comparison accuracy.

The threshold value can be set as shown in the concept shown in FIG. There are three types of threshold values shown in FIG. 6, which may be defined values or accept values from the parameter input unit 11 each time.
The first threshold value in this figure is a threshold value that determines the lower limit of the amplitude peak of the target amplitude extraction results 310 to 312 to be compared.
The second threshold value is a threshold value that defines a lower limit that is a range for calculating the sum of amplitudes of the target amplitude extraction results 310 to 312 to be compared.
The third threshold value is a threshold value that determines the upper limit of the difference in amplitude peak between the target amplitude extraction results 310 to 312 to be compared.
Note that the comparison may be performed using only one or two of the threshold values. In addition, a threshold value for obtaining amplitude image data closer to the ideal shape, a threshold value for reducing the amount of calculation processing, and the like may be added as appropriate. These values are input as parameter input unit output data 111.

FIG. 7 is an explanatory diagram showing a speed calculation method from amplitude image data related to each target using the three types of thresholds exemplified.
Each target amplitude detection unit 38 to 40 uses the first threshold value and the second threshold value, and uses the first threshold value and the second threshold value in the vicinity of the position (X, Y) indicated by the target position information 203 from the amplitude image data 307 to 309. Extract the target amplitude by calculating the peak amplitudes P1 to P3, the spread around the peak (half-value width from the peak amplitude) W1 to W3, and the sum of the amplitudes S1 to S3 in the range including the peak It outputs as result information 310-311. In this example, the values of P1 to P3 to be converted into data are larger than the first threshold value, and the values of S1 to S3 are larger than the second threshold value.

  The speed determination unit 41 receives the target amplitude extraction result information 310 to 311 as input, compares the values of P1, P2, and P3, and the target traveling direction speed VTX when the value is the largest (here, X is 1 to 1). 3) is output as traveling direction speed information 204. At this time, if there is a combination that exceeds the third threshold, the difference based on the maximum value of P1, P2, and P3 is compared between the combinations that do not exceed, but still exceeds the third threshold Judges that the assumed speed is far from the ideal shape, and determines the combination by removing the data. For example, if the third threshold value is exceeded between P1 and P2 and the third threshold value is not exceeded between P1 and P3, a determination is made between P1, P2, and P3, but between P1 and P2 If the third threshold value is exceeded and the third threshold value is also exceeded between P1 and P3, P1 is removed and the determination is made between P2 and P3. When the third threshold value is exceeded in any combination, the values of W1, W2, and W3 are compared, and the target traveling direction speed VTX at the smallest value is output as the traveling direction speed information 204. If none of the peak amplitudes exceeds the first threshold, the values of S1, S2, and S3 are compared, and the target traveling direction velocity VTX when the value is the largest is output as the traveling direction velocity information 204. .

  In other words, when the speed determination unit 41 compares the amplitude image data for each processing parameter detected using the three types of threshold values, the speed determination unit 41 starts from the highest peak value of the plurality of amplitude image data to be compared. When there is an amplitude image in which the difference exceeds the third threshold value, the assumed speed of the processing parameter that has the highest peak value among the plurality of amplitude image data to be compared and exceeds the first threshold value is set as the target. Calculated as the speed in the direction of travel. In addition, when the difference between the peaks of the plurality of amplitude image data to be compared exceeds the third threshold, the determination is made between those not exceeding the third threshold. Further, when the combination between all the peaks exceeds the third threshold value, the assumed speed of the processing parameter having a narrow amplitude spread is calculated and output as the traveling direction speed information 204 indicating the traveling direction speed of the target. . When there is no amplitude image exceeding the first threshold, the assumed speed of the processing parameter including a peak of amplitude among the plurality of amplitude image data to be compared and having a large sum of amplitudes in the range exceeding the second threshold The traveling direction speed information 204 indicating the traveling direction speed of the target is calculated and output.

  This data processing is an example, and any data format may be used as long as the amplitude image data for each processing parameter can be significantly compared.

As described above, the process of selecting image data closer to the ideal shape using the target amplitude extraction result information 310 to 312 includes the amplitude intensity and the spread of the moving target object reflected in the image that can be acquired by the synthetic aperture radar, the image The correlation between the speed used in the reproduction process and the actual speed is used. In other words, the correlation between the speed used in the image reproduction process and the actual speed (the true speed of the target) is obtained so that the closer to the actual speed, the higher the intensity and the narrower the image data.
Therefore, from the amplitude image data relating to the target in the image obtained as a result of the SAR image reproduction processing using a plurality of processing parameters (a plurality of assumed speed information) assuming the traveling direction speed of the target, as described above. A processing parameter capable of obtaining amplitude image data close to the ideal shape is derived, and the velocity component in the traveling direction is calculated from the value. For this reason, it is calculated | required with high precision rather than detecting the speed information of the advancing direction of a target with another method.
That is, it is possible to provide a synthetic aperture radar system that can calculate the moving direction speed of the moving target with high definition from the acquired data.

  Next, a plurality of other embodiments of the present invention will be described.

[Second Embodiment]
FIG. 8 is an explanatory diagram for explaining the second embodiment. In the second embodiment, in addition to the configuration of the first embodiment described above, the initial parameter given to the traveling direction velocity calculation unit 24 is the rough velocity of the target obtained from the SAR / GMTI processing unit 8 or another system. The input parameter conversion unit 27 is selected systematically using the.

  The input parameter conversion unit 27 includes the parameters previously given to the traveling direction speed calculation unit 24, the target traveling direction speed information 204 obtained from the traveling direction speed calculation unit 24, the movement target and distance direction speed calculation unit 23, and other systems. Using the target speed or the traveling direction speed obtained from the above, the conversion is performed to adaptively adjust the initial speed and deviation in the parameter input unit output data 111, and the converted parameters are input to the traveling direction speed calculation unit 24 as parameters. Input as partial output data 112. The adjustment here may be performed by changing the initial speed, limiting the deviation, or setting the estimated speed to the initial speed when the target acceleration is known.

  The traveling direction speed calculation unit 24 receives an initial parameter (adjusted initial parameter) assuming the traveling direction speed of the target in the converted parameter input unit output data 112 from the input parameter conversion unit 27, and receives the initial parameter and the platform. A plurality of processing parameters assuming the traveling direction speed of the target determined based on the speed of 12 are generated and used to calculate the traveling direction speed of the target.

By such processing, the SAR / GMTI processing unit 8 uses the target traveling direction velocity calculated by the above processing to obtain a high-precision target velocity that is closer to the true velocity of the target in the image from the rough velocity of the target. Can be identified.
In other words, since the input parameter conversion unit 27 selects a better initial parameter from the input speed or the like, it is possible to obtain a speed with higher accuracy even from a speed (approximately the same level as the existing technology). It becomes possible with the amount of calculation.

[Third Embodiment]
FIG. 9 is an explanatory diagram for explaining the third embodiment. In the third embodiment, an image of a portion including a target performed by the SAR / GMTI processing unit 8 (image generation unit 26) using the highly accurate target traveling direction velocity information calculated by the traveling direction velocity calculation unit 24. A drawing correction unit 45 that corrects (complements) the drawing is provided.

  The drawing correction unit 45 may be provided in the traveling direction speed calculation unit 24 as illustrated, or may be provided outside the traveling direction speed calculation unit 24 such as in the image generation unit 26.

From the traveling direction speed calculation unit 24 shown in FIG. 9, which target amplitude detection unit, that is, from which image generation unit the amplitude data is adopted as a source when the optimum assumed speed selection process is performed. Is output to the drawing correction unit 45.
Based on the selection number 320, the drawing correction unit 45 extracts an image related to the vicinity of the target from the amplitude image data of the processing parameter regarded as the traveling direction speed of the target, and outputs it as the selected target amplitude image 602.
The display / recording unit 10 may combine the selected target amplitude image 602 and the amplitude image data 109 to generate a single image, or display only the corresponding portion as a separate frame.

FIG. 10 is a block diagram illustrating a configuration example of the drawing correction unit 45.
An image selection unit 61 shown in the figure receives input of amplitude image data 307 to 309 and selection number 320 output from the image generation units 35 to 37.
The image selection unit 61 selects any one of the amplitude image data 307 to 308 based on the selection number 320 and outputs a selected amplitude image 601.
The image cutout unit 62 receives the selected amplitude image 601 and the target position information 203, performs a process of cutting out a certain area centered on the target from the selected amplitude image 601, and outputs the cut out image as the selected target amplitude image 602. To do.

  Further, as the drawing correction means, an image obtained by correcting the depiction of the portion in the vicinity of the target from the complex image data obtained from the SAR image reproduction processing unit, using the traveling direction velocity of the target obtained by the traveling direction velocity calculation unit 24. You may replace with.

  By performing such correction, it is possible to obtain a high-definition image in which the image depiction in the vicinity of the target is corrected and the target is stationary.

  Although a plurality of embodiments have been described above, the present invention is not limited to the above-described embodiments, and various modifications such as separation / merging of block configurations and replacement of procedures are allowed without departing from the scope of the invention. is there.

  In each of the above embodiments, the SAR / GMTI processing unit is described as being formed by dedicated hardware, but this can also be realized by installing appropriate software in a general computer system. is there.

  In this case, the traveling direction speed calculation program is expanded in the RAM of the information processing apparatus that operates as the traveling direction speed calculation device, and hardware such as a control unit (CPU) is operated based on the program. Thus, each unit is operated as various means. Further, this program may be recorded on a storage medium and distributed. The program recorded on the recording medium is read into a memory via a wired, wireless, or recording medium itself, and operates a control unit or the like.

  In other words, the information processing apparatus operating as the traveling direction speed calculating device is based on the traveling direction speed calculating program developed in the RAM, and the traveling direction speed calculating means (image reproduction processing parameter) is described. The calculation means can be realized by operating the control unit as SAR image reproduction processing means, image generation means, target amplitude detection means, speed determination means), input parameter conversion means, drawing correction means, and the like.

  Also, the processing performed by dedicated hardware and software can be appropriately configured by appropriately combining them.

  In the above embodiment, the entire synthetic aperture radar system 1 is mounted on the platform 12. For example, the mobile platform 12 includes only the components related to the measurement of the antenna unit 2, the flight information detection unit 9, and the like. The SAR / GMTI processing unit 8 and the display / recording unit 10 can be installed in a distributed manner such that the SAR / GMTI processing unit 8 and the display / recording unit 10 are installed in an information processing center on the ground that wirelessly communicates with the platform 12. .

  In addition, in the traveling direction velocity calculation unit 24 in FIG. 3, the SAR image reproduction processing units 32 to 34, the image generation units 35 to 37, and the target amplitude detection units 38 to 40 detect the velocity from the three amplitude data. However, for example, each configuration may be two or four or more, and the number of simultaneous parallel processes may be adjusted. Note that the comparison is not the amplitude image data near the target obtained by simultaneous parallel processing, but the amplitude image data near the target obtained from the same measurement data using a plurality of processing parameters assuming the traveling speed of the target. Can be used. For this reason, it is also possible to calculate the target traveling direction speed by sequentially detecting the amplitude data of a plurality of processing parameters using the same SAR image reproduction processing unit or the like and comparing them.

  In the above-described embodiment, the reception unit 5 and the signal processing unit 7 are mounted in the synthetic aperture radar system 1 and the reception wave 103 from the antenna unit 3 is received and processed. Thus, the reception wave 5 from the antenna unit 2 and the reception wave 103 from the antenna unit 3 are received while being switched, and the signal processing unit 6 performs predetermined signal processing, so that the reception unit 5 and the signal processing unit 7 are not required. A configuration is also possible.

  Further, as flight information detection unit output data 108 from the flight information detection unit 9 in FIG. 1, accuracy is improved by known post-processing on the ground in addition to directly using information from a sensor device mounted on the platform. It is also possible to use location information.

  Moreover, although the said embodiment limited and demonstrated the target to one, you may process in parallel about several targets simultaneously. In this case, it is possible to obtain and use the highly accurate traveling direction speed of each of the plurality of targets included in the image to be drawn.

  In addition, although the aircraft is illustrated in FIG. 4 as the moving platform 12, a satellite or other flying object may be used. In the case of a satellite, in addition to using a sensor device mounted on the satellite, it is possible to use position information with higher accuracy by known post-processing on the ground. Further, as post-processing on the ground, it can be obtained by the traveling direction speed estimation method using a plurality of assumed processing parameters as described above, or a description image can be corrected.

  As described above, the target traveling direction speed is determined by comparing the difference in amplitude and amplitude spread of the target on the image caused by the difference in the assumed traveling direction speed of the target. In order to use the intensity and spread of the moving target in this synthetic aperture radar image, in multiple images acquired from the results of SAR image reproduction processing using multiple assumed multiple processing parameters (assumed velocity information) Amplitude image data of the target is obtained and compared.

  By combining the target traveling direction velocity and the distance direction velocity in the SAR image by such hardware or software processing or a combination thereof, it is possible to calculate the target velocity vector and generate the image with high accuracy. For this reason, the reliability of the speed detection of the moving object in the synthetic aperture radar image can be improved.

  Such image processing may be performed in real time on the moving platform, or may be performed later on a system outside the platform. When performing this image processing on the platform, high-precision, high-definition functions such as target detection, moving direction display, moving speed display, enlarged image display, etc. are obtained in real time from the acquired data obtained from the antenna of the synthetic aperture radar. Can be done.

As described above, according to the present invention, it is possible to provide a synthetic aperture radar system capable of calculating the moving direction speed of a moving target with high definition from acquired data.
In addition, it is possible to provide a synthetic aperture radar system that can accurately determine a velocity vector of a moving target using the velocity in the obtained traveling direction.
In addition, it is possible to provide a synthetic aperture radar system that can obtain an accurate moving target image based on the obtained speed in the traveling direction.

A part or all of the above-described embodiments can be described as follows. Note that the following supplementary notes do not limit the present invention.
[Appendix 1]
Using a plurality of processing parameters assuming the traveling speed of the target, amplitude image data in the vicinity of the target is detected for each processing parameter, and a plurality of amplitude image data for each detected processing parameter is compared to find an ideal A traveling direction speed calculating means for performing processing for regarding the traveling direction speed indicated by the processing parameter of the amplitude image data close to the shape as the traveling direction speed of the target;
A synthetic aperture radar system characterized in that the speed in the direction of travel of a target is calculated from acquired data obtained from an antenna.

[Appendix 2]
The traveling direction speed calculating means, when comparing the amplitude image data for each detected processing parameter,
Using the first threshold value that defines the lower limit of the amplitude peak of the amplitude image data to be compared and the second threshold value that defines the lower limit of the range of the total sum calculation of the amplitude of the amplitude image data to be compared,
The assumed speed of the processing parameter that exceeds the first threshold and has the highest peak value in the amplitude image data to be compared is calculated as the traveling direction speed of the target,
When there is no amplitude image exceeding the first threshold value, the assumed speed of the processing parameter having a narrow amplitude spread in the range exceeding the second threshold value among the plurality of amplitude image data to be compared is set as the target progresses. The synthetic aperture radar system according to the above supplementary note, wherein the synthetic aperture radar system is calculated as a directional velocity.

[Appendix 3]
The traveling direction speed calculating means, when comparing the amplitude image data for each detected processing parameter,
A first threshold value that defines a lower limit of an amplitude peak of amplitude image data to be compared, a second threshold value that defines a lower limit that is a range for calculating the sum of amplitudes of amplitude image data to be compared, and an amplitude to be compared Using a third threshold that defines the upper limit of the difference in amplitude peaks between image data,
When there is an amplitude image in which the difference between the peaks of the plurality of amplitude image data to be compared exceeds the third threshold value, a comparison is made between combinations of amplitude image data that do not exceed the third threshold value. An assumed speed of a processing parameter exceeding the threshold value of 1 and having the highest peak value in the amplitude image data to be compared is calculated as a traveling direction speed of the target;
A plurality of amplitudes to be compared when only a combination in which a difference between peaks of a plurality of amplitude image data to be compared exceeds the third threshold value and when there is no amplitude image data exceeding the first threshold value The synthetic aperture radar system according to the above supplementary note, wherein an assumed speed of a processing parameter having a narrow amplitude spread in a range exceeding the second threshold in image data is calculated as a target traveling direction speed.

[Appendix 4]
The advancing direction speed calculation means calculates an assumed speed of a processing parameter having a high peak value as a traveling direction speed of the target when comparing the detected amplitude image data for each processing parameter. The described synthetic aperture radar system.

[Appendix 5]
The traveling direction speed calculating means calculates an assumed speed of a processing parameter having a narrow amplitude spread width as a traveling direction speed of the target when comparing the amplitude image data for each detected processing parameter. The synthetic aperture radar system as described in the above supplementary note.

[Appendix 6]
As the MTI (Moving Target Indicator) processing unit for performing the moving target detection processing, the traveling direction speed calculation means is included,
An input parameter converting means for automatically selecting an initial parameter to be given to the traveling direction speed calculating means using a target speed obtained from the moving target detection process;
The traveling direction speed calculating means receives an initial parameter assuming the converted target traveling speed from the input parameter converting means, and assumes a target traveling speed determined based on the initial parameter and the platform speed. Generate and use multiple processing parameters, and calculate the target traveling direction speed,
The synthetic aperture radar system according to the above supplementary note, wherein the MTI processing unit specifies a target velocity that is finer than the target velocity obtained from the processing, using the calculated target traveling velocity.

[Appendix 7]
The synthetic aperture radar system according to the above supplementary note, further comprising: a drawing correction unit that corrects the drawing of the image related to the target based on the calculation result of the traveling direction velocity calculation unit.

[Appendix 8]
An image reproduction processing parameter calculation unit that generates and processes a plurality of processing parameters assuming a traveling direction speed of the target;
Using each processing parameter assuming the traveling direction speed of the target, a SAR image reproduction processing unit group that reproduces a plurality of complex image data,
A group of image generation units for generating and processing amplitude image data from each of a plurality of reproduced complex image data;
A target amplitude detector group for extracting amplitude image data in the vicinity of the target from each of the reproduced plurality of amplitude image data;
The generated amplitude image data regarding the target for each of the plurality of processing parameters is compared so as to select amplitude image data close to an ideal shape, and the traveling direction speed indicated by the processing parameter specified by the comparison is determined as the progress of the target. A speed determining unit that outputs as a direction speed;
A synthetic aperture radar system comprising:

[Appendix 9]
Means for detecting amplitude image data in the vicinity of the target for each of the processing parameters using a plurality of processing parameters assuming a traveling direction speed of the target;
Comparing a plurality of amplitude image data for each detected processing parameter, and comprising means for performing processing that considers the traveling direction speed indicated by the processing parameter of the amplitude image data close to the ideal shape as the traveling direction speed of the target,
A traveling direction velocity calculating apparatus that calculates a traveling direction velocity of a target from acquired data obtained from a synthetic aperture radar.

[Appendix 10]
An image reproduction processing parameter calculation unit that generates and processes a plurality of processing parameters assuming a traveling direction speed of the target;
Using each processing parameter assuming the traveling direction speed of the target, a SAR image reproduction processing unit group that reproduces a plurality of complex image data,
A group of image generation units for generating and processing amplitude image data from each of a plurality of reproduced complex image data;
A target amplitude detector group for extracting amplitude image data in the vicinity of the target from each of the reproduced plurality of amplitude image data;
The generated amplitude image data regarding the target for each of the plurality of processing parameters is compared so as to select amplitude image data close to an ideal shape, and the traveling direction speed indicated by the processing parameter specified by the comparison is determined as the progress of the target. A speed determining unit that outputs as a direction speed;
A traveling direction velocity calculation device comprising:

[Appendix 11]
Using a plurality of processing parameters assuming the traveling speed of the target, amplitude image data in the vicinity of the target is detected for each processing parameter,
Comparing a plurality of detected amplitude image data for each processing parameter, performing a process that considers the traveling direction speed indicated by the processing parameter of the amplitude image data close to the ideal shape as the traveling direction speed of the target,
A traveling direction velocity estimation method, wherein the traveling direction velocity of a target is calculated from acquired data obtained from a synthetic aperture radar.

[Appendix 12]
Generate and process multiple processing parameters assuming the target traveling speed
As processing parameters given to the SAR image playback processing unit, using each processing parameter assuming the traveling speed of the target, playback processing of a plurality of complex image data,
Amplitude image data is generated from each of the reproduced complex image data,
Extract the amplitude image data near the target from each of the reproduced multiple amplitude image data,
Amplitude image data related to the target for each of the plurality of processing parameters is compared so as to select amplitude image data close to an ideal shape, and the traveling direction speed indicated by the processing parameter specified in the comparison is determined as the traveling direction of the target. A traveling direction speed estimation method, characterized in that a traveling direction speed of a target is calculated from acquired data obtained from a synthetic aperture radar by outputting as a speed.

  The present invention can be used for analysis of measurement data acquired by a synthetic aperture radar system. This analysis can be performed in real time or can be performed after the fact.

1 Synthetic Aperture Radar System 2, 3 Antenna Unit (Radio Wave Transmitter / Receiver)
4 Transmitter / receiver (radio wave transmission means)
5 Receiving part (Radio wave receiving means)
6, 7 Signal processing unit (signal processing means)
8 SAR / GMTI processing part (SAR processing means / GMTI processing means)
9 Flight information detection unit (flight information detection means, movement information detection means)
10 Display / Recording Unit (Display Unit / Recording Unit)
11 Parameter input section (parameter input means)
DESCRIPTION OF SYMBOLS 12 Mobile platform 13 Ground 14 which is object surface Targets 21 and 22 which are movement targets SAR image reproduction | regeneration processing part (SAR image reproduction | regeneration processing means)
23 Moving target detection and distance direction speed calculation unit (moving target detection means / distance direction speed calculation means)
24 Traveling direction speed calculation unit (traveling direction speed calculation means)
25 Speed synthesis unit (speed synthesis means)
26 Image generation unit (image generation means)
27 Input parameter converter (input parameter converter)
31 Image reproduction processing parameter calculation unit (image reproduction processing parameter calculation means)
32-34 SAR image reproduction processing unit (SAR image reproduction processing means)
35-37 Image generation part (image generation means)
38 to 40 target amplitude detector (target amplitude detector)
41 Speed determining unit (speed determining means)
45 Drawing Correction Unit (Drawing Correction Unit)
61 Image selection unit (image selection means)
62 Image cutout part (image cutout means)
101 Transmission wave 102, 103 Reception wave 104, 105 Video signal 106, 107 Signal processing unit output signal 108 Flight information detection unit output data 109 Amplitude image data 110 GMTI data 111 Parameter input unit output data 201, 202 Complex image data 203 Target position Information 204 Traveling direction velocity information 205 Distance direction velocity information 301 to 303 Corrected flight information detection unit output data 304 to 306 Complex image data 307 to 309 Amplitude image data 310 to 312 Target amplitude extraction result information 320 Selection number 601 Selection amplitude image 602 Selected target amplitude image

Claims (8)

Amplitude image data for each processing parameter is generated by executing SAR image reproduction processing and amplitude conversion processing for each processing parameter using a plurality of processing parameters assuming a target platform traveling direction velocity component, and the target The position information is received, the target position information is referred to, the amplitude image data in the vicinity of the target for each generated processing parameter are compared, and the set of amplitude values for the position in the platform traveling direction of the reaction occurring in the vicinity of the target About the peak value SAR / GMTI (Synthetic Aperture Radar / Synthetic Aperture Radar / Ground Moving Target Indicator) Prepare in the processing section,
From the acquired data obtained from the antenna, the target traveling direction speed is calculated based on the target platform traveling direction speed component calculated by the traveling direction speed calculating means and the target platform distance direction speed component calculated separately. A synthetic aperture radar system characterized by that. The advancing direction speed calculating means compares the amplitude image data for each processing parameter with each other and compares the amplitude image data for each processing parameter with the platform indicated by the target position information detected in the moving target detection processing from the amplitude image data for each processing parameter. By referring to the peak values of each amplitude value set appearing in the position coordinates in the traveling direction, the amplitude image data having a stronger amplitude value is identified, and the platform traveling direction indicated by the processing parameter of the amplitude image data The synthetic aperture radar system according to claim 1, wherein the velocity component is identified as a velocity component in the direction of travel of the platform of the target. The advancing direction speed calculation means indicates the target position information detected by the moving target detection process in which the amplitude image data for each processing parameter satisfies a predetermined criterion when comparing the amplitude image data for each processing parameter. In the case of a combination of amplitude image data that does not have any peak value of each amplitude value set appearing in the position coordinates in the platform traveling direction, the moving target detection processing is performed from the amplitude image data for each processing parameter. The amplitude image data having a narrower amplitude set is identified by referring to the widths of the respective amplitude value sets shown in the position coordinates of the platform traveling direction indicated by the detected target position information, and the amplitude The platform traveling direction speed component indicated by the processing parameter of the image data is the platform traveling direction speed component of the target. Synthetic aperture radar system according to claim 1 or 2, characterized in that identified. The traveling direction speed calculation means, when comparing the generated amplitude image data for each processing parameter,
A first threshold value that defines a lower limit value of a peak of an amplitude value set that determines whether or not to use each amplitude image data to be compared; and a smaller value than the first threshold value for each amplitude image data to be compared With a second threshold that defines the lower limit of the amplitude spread range,
The value of the assumed speed of the processing parameter that exceeds the first threshold and has the highest peak value among the amplitude image data for each processing parameter to be compared is used as the platform traveling direction speed component of the target. Identify and
When there is no amplitude image data exceeding the first threshold, the assumed speed of the processing parameter with the narrowest amplitude spread in the range exceeding the second threshold among the amplitude image data for each processing parameter to be compared The synthetic aperture radar system according to any one of claims 1 to 3, characterized in that is identified as a velocity component in a traveling direction of the target. The traveling direction speed calculation means, when comparing the generated amplitude image data for each processing parameter,
A first threshold value that defines a lower limit value of a peak of an amplitude value set that determines whether or not to use each amplitude image data to be compared; and a smaller value than the first threshold value for each amplitude image data to be compared In addition to the second threshold value that defines the lower limit of the amplitude spread range,
Based on the maximum amplitude peak value between the respective amplitude image data to be compared, the third threshold is used to determine the allowable difference between the amplitude peak values of the other amplitude image data with respect to the maximum amplitude peak value. The synthetic aperture radar system according to claim 4, wherein the synthetic aperture radar system is identified as a directional velocity component. The SAR / GMTI processing unit includes an input parameter conversion unit that inputs a processing parameter converted based on a target platform traveling direction speed component output from the traveling direction speed calculating unit to the traveling direction speed calculation unit,
The synthetic aperture radar system according to any one of claims 1 to 5, wherein the SAR / GMTI processing unit repeats parameter adjustment given to the traveling direction velocity calculation unit via the input parameter conversion unit. . 7. The SAR / GMTI processing unit, for a plurality of targets, identifies the platform traveling direction speed component of each target using the traveling direction speed calculating means by simultaneous parallel processing. The synthetic aperture radar system according to claim 1. An image reproduction processing parameter calculation unit for generating and processing a plurality of processing parameters assuming a target platform traveling direction velocity component;
SAR image reproduction processing unit group that reproduces complex image data for each processing parameter by SAR image reproduction processing, using each processing parameter assuming a target platform traveling direction velocity component;
An image generation unit group that generates and processes amplitude image data from the reproduced complex image data for each processing parameter, respectively, by amplitude conversion processing;
The target position information generated by the SAR / GMTI process is received, the target position information is referred to, and each amplitude value set appearing in the position coordinates in the platform traveling direction from the generated amplitude image data for each processing parameter. A target amplitude detection unit group that respectively extracts and
The extracted amplitude value sets for each processing parameter are compared so as to select amplitude image data of the processing parameter that has a stronger intensity or a narrower width when there is no one having a predetermined intensity. A speed determining unit that outputs a platform traveling direction speed component indicated by the selected processing parameter as a platform traveling direction speed component of the target;
In the SAR / GMTI processing section ,
From the acquired data obtained from the antenna, the target traveling direction speed is calculated based on the target platform traveling direction speed component calculated by the speed determining unit and the target platform distance direction speed component calculated separately <br> A synthetic aperture radar system characterized by the above.

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