JP2013200207A - Motion estimation apparatus, signal processing apparatus, computer program and motion estimation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly estimate a moving speed of a whole target even in the case where a target itself is rotating.SOLUTION: A degree of correlation maximum speed determining section 45 (partial speed estimation section), regarding each of azimuth lines (partial signal) divided by an azimuth line dividing section 42, estimates moving speed (partial speed) of a part of a target that a synthetic aperture radar 21 observed corresponding to the azimuth line. An approximation straight line section 50 (motion separating section) separates a motion of a whole target from a rotational motion of the target itself based on the speed estimated by the degree of correlation maximum speed determining section 45. A moving speed calculating section 52, based on the motion of the whole target separated by the approximation straight line calculating section 50, calculates moving speed by the motion of the whole target.

Description

  The present invention relates to a motion estimation apparatus that estimates a target speed and angular velocity from observation results obtained by a synthetic aperture radar.

In the azimuth compression of the observation signal from the synthetic aperture radar, the resolution can be increased by using a reference function that matches the relative velocity between the synthetic aperture radar and the target. Usually, since the moving speed of the synthetic aperture radar itself is known, it is important to correctly estimate the moving speed of the target.
Assuming multiple speeds as target movement speeds, azimuth compression is performed using a reference function that matches each of the assumed speeds, and the peak value of the signal after azimuth compression is compared. There is a technique for determining that the speed is a target moving speed.

JP 2007-114093 A Japanese Patent Laid-Open No. 2007-114098 JP 2007-292532 A JP 2011-191267 A

In the conventional technique, if the moving speed differs for each part of the target such as the target itself rotating in addition to the movement of the entire target, the moving speed of the target may not be correctly determined. For example, if reflection from a certain part is strong, there is a possibility that the moving speed of that part is determined to be the moving speed of the entire target.
An object of the present invention is to correctly estimate the moving speed of the entire target even when the target itself is rotating, for example.

The motion estimation apparatus according to the present invention includes:
A partial speed estimation unit, a motion separation unit, and a movement speed calculation unit;
The partial velocity estimation unit estimates the moving speed of the portion for each of a plurality of portions obtained by dividing the target observed by the synthetic aperture radar based on the signal output by the synthetic aperture radar,
The motion separation unit separates the motion of the entire target and the rotational motion of the target itself based on the speed estimated by the partial speed estimation unit for each of the plurality of portions.
The moving speed calculation unit calculates a moving speed due to the movement of the entire target based on the movement of the entire target separated by the movement separating unit.

The partial speed estimation unit divides the target into the plurality of parts based on the distance in the range direction,
The motion separation unit calculates a linear function that approximates the moving speed estimated by the partial speed estimation unit for each of the plurality of parts as a function of the distance in the range direction,
The moving speed calculating unit calculates a moving speed of a portion that is the center of the target based on the linear function calculated by the motion separating unit, and sets the moving speed by the movement of the entire target. .

The motion estimation apparatus further includes a signal dividing unit,
The signal dividing unit divides the signal before azimuth compression based on the signal output from the synthetic aperture radar into a plurality of partial signals based on the distance in the range direction,
The partial speed estimation unit estimates a moving speed of the target portion corresponding to the partial signal based on each of the plurality of partial signals divided by the signal division unit.

  The moving speed calculation unit calculates the moving speed in the range direction due to the movement of the entire target, assuming that the entire target does not move in the height direction, and calculates the moving speed in the range direction to the ground range. It is characterized by converting to a moving speed in the direction.

The motion estimation device further includes an angular velocity calculation unit,
The angular velocity calculation unit calculates an angular velocity due to the rotational motion of the target itself based on the rotational motion of the target itself separated by the motion separation unit.

  The angular velocity calculation unit is configured to determine an angular velocity due to the rotational motion of the target itself based on a change rate of a difference between the movement velocity estimated by the partial velocity estimation unit for each of the plurality of portions and the movement velocity due to the motion of the entire target. Is calculated.

The signal processing apparatus according to the present invention is:
The motion estimation device;
An azimuth compression unit that compresses a signal before azimuth compression based on a signal output from the synthetic aperture radar on the assumption that the moving speed of the entire target estimated by the motion estimation device is the target speed. It is characterized by having.

The computer program according to the present invention is:
When executed by the computer, the computer functions as the motion estimation device or the signal processing device.

The motion estimation method according to the present invention includes:
In the motion estimation method for estimating the motion of the target observed by the synthetic aperture radar based on the signal output by the synthetic aperture radar,
Based on the signal output by the synthetic aperture radar, for each of a plurality of portions obtained by dividing the target observed by the synthetic aperture radar, the moving speed of the portion is estimated,
Based on the speed estimated for each of the plurality of parts, the overall movement of the target and the rotational movement of the target itself are separated,
Based on the separated movement of the entire target, a moving speed due to the movement of the entire target is calculated.

  The movement speed of the entire target is separated from the rotational movement of the target itself, and the movement speed due to the movement of the entire target is calculated. it can.

1 is a configuration diagram illustrating an example of an overall configuration of a synthetic aperture radar observation system 10 according to a first embodiment. FIG. 3 is a hardware configuration diagram illustrating an example of hardware resources of the signal processing device 13 according to the first embodiment. FIG. 3 is a block configuration diagram showing an example of functional blocks of a motion estimation device 34 in the first embodiment. The figure for demonstrating the operation principle of the motion estimation apparatus in Embodiment 1. FIG. The figure for demonstrating the operation principle of the motion estimation apparatus in Embodiment 1. FIG. FIG. 3 is a flowchart showing an example of a flow of motion estimation processing S10 in the first embodiment. The block block diagram which shows an example of the functional block of the motion estimation apparatus 34 in Embodiment 2. FIG. FIG. 11 is a flowchart showing an example of a flow of motion estimation processing S10 in the second embodiment.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

  FIG. 1 is a configuration diagram showing an example of the overall configuration of a synthetic aperture radar observation system 10 in this embodiment.

The synthetic aperture radar observation system 10 is a system that observes the target 70 and the like using the synthetic aperture radar 21. The synthetic aperture radar observation system 10 includes, for example, an observation satellite 12 and a signal processing device 13.
The observation satellite 12 is equipped with a synthetic aperture radar 21. The observation satellite 12 is an example of a platform. The observation satellite 12 orbits the low orbit, for example. The observation satellite 12 is moving at a speed of 76. The direction in which the observation satellite 12 is moving is called the “azimuth direction”.
The synthetic aperture radar 21 transmits a pulse 61 obtained by chirp-modulating a radio wave such as a microwave toward the ground surface, for example, and receives a reflected wave 62 reflected by the pulse 61 hitting the target 70 or the like. The synthetic aperture radar 21 outputs a signal 81 indicating the intensity of the received reflected wave 62.

  In the portion of signal 81 corresponding to one cycle of transmission of pulse 61, the delay time from transmission of pulse 61 to reception of reflected wave 62 represents the distance (range direction distance) from synthetic aperture radar 21 to target 70. . At the time of transmission of the next pulse 61, the observation satellite 12 is moving in the azimuth direction, so that the position of the target 70 in the azimuth direction is known from the change in the range direction distance. Of the signal 81, a portion obtained by extracting a portion having the same delay time from the transmission of the pulse 61 from each cycle of the transmission of the pulse 61 is referred to as an “azimuth line”. The azimuth line includes reflections from the target 70 at the same range direction distance.

The signal processing device 13 processes the signal output from the synthetic aperture radar 21 to generate, for example, an image of the ground surface observed by the synthetic aperture radar 21. Further, the signal processing device 13 outputs additional information such as the moving speed and rotational speed of the target 70 observed by the synthetic aperture radar 21. The signal processing device 13 may be configured to be mounted on the observation satellite 12.
For example, the signal processing device 13 includes a range compression unit 31, a first azimuth compression unit 32, a target extraction unit 33, a motion estimation device 34, a second azimuth compression unit 35, an image generation unit 36, and additional information. And a generation unit 37.

The range compressor 31 receives the signal 81 from the synthetic aperture radar 21 and performs range compression. Range compression increases the resolution in the range direction.
The first azimuth compressing unit 32 inputs the signal 82 compressed by the range compressing unit 31 and performs azimuth compression. The first azimuth compression unit 32 performs azimuth compression using a reference signal that assumes that the target 70 is stationary. Since the azimuth compression is performed on the assumption that the target 70 is stationary, the lower the moving speed 71 of the target 70, the higher the resolution in the azimuth direction.
The target extraction unit 33 extracts a portion that is a reflection from the target 70 from the signal 83 azimuth-compressed by the first azimuth compression unit 32.

  The motion estimation device 34 receives a signal 84 indicating which part the target extraction unit 33 has extracted. The motion estimation device 34 inputs a signal 82 corresponding to a portion extracted by the target extraction unit 33 in the signal 82 subjected to range compression by the range compression unit 31. The motion estimation device 34 estimates the moving speed 71 and the rotational speed of the target 70 based on the signal 82. The motion estimation device 34 estimates, for example, a velocity vector having components of the azimuth direction velocity 72 and the range direction velocity 73 of the target 70. In addition, the motion estimation device 34 estimates, for example, the angular velocity of the target 70 with the azimuth direction as an axis and the angular velocity of the target 70 with the height direction as an axis.

  The second azimuth compression unit 35 (azimuth compression unit) receives a signal 84 indicating which part the target extraction unit 33 has extracted. The second azimuth compression unit 35 receives a signal 85 representing the moving speed 71 and the angular speed estimated by the motion estimation device 34. The second azimuth compression unit 35 inputs a signal 82 corresponding to a portion extracted by the target extraction unit 33 in the signal 82 subjected to range compression by the range compression unit 31. The second azimuth compressing unit 35 performs azimuth compression on the input signal 82 using a reference signal that assumes that the target 70 is moving at the moving speed 71 estimated by the motion estimation device 34.

  The image generation unit 36 receives the signal 83 compressed by the first azimuth compression unit 32 and the signal 86 compressed by the second azimuth compression unit 35 and generates an image. By using the signal 86 for the part extracted by the target extraction unit 33 and using the signal 83 for the other part, the image generation unit 36 generates a clear image with high overall resolution.

  The additional information generation unit 37 receives a signal 85 representing the moving speed 71 and the angular speed estimated by the motion estimation device 34. The additional information generation unit 37 generates and outputs information indicating the moving speed 71 and the angular speed of the target 70 represented by the input signal 85.

  As will be described later, the motion estimation device 34 azimuthally compresses the signal 82 in order to estimate the moving speed 71 of the target 70. Therefore, the motion estimation device 34 may be configured to output the azimuth compressed signal 86. In that case, the 2nd azimuth compression part 35 does not need to be.

  FIG. 2 is a hardware configuration diagram illustrating an example of hardware resources of the signal processing device 13 according to this embodiment.

The signal processing device 13 includes, for example, a processing device 91, an input device 92, an output device 93, and a storage device 94.
The processing device 91 processes the data by executing a program (computer program) stored in the storage device 94 and controls the input device 92 and the output device 93.
The storage device 94 stores a program executed by the processing device 91 and data processed by the processing device 91. The storage device 94 is, for example, a semiconductor memory, a magnetic disk device, an optical disk device, or the like.
The input device 92 inputs a signal from the outside and converts it into data that can be processed by the processing device 91. The data converted by the input device 92 may be processed directly by the processing device 91 or may be stored temporarily by the storage device 94. The input device 92 is, for example, a keyboard, a mouse, a camera, a scanner, a microphone, a sensor, an analog / digital conversion circuit, a receiving device, or the like.
The output device 93 converts the data processed by the processing device 91 and the data stored in the storage device 94 and outputs them to the outside. The output device 93 is, for example, an image display device, a printer, a speaker, a digital / analog conversion circuit, a transmission device, or the like.

  The blocks constituting the signal processing device 13 such as the motion estimation device 34 can be realized by the processing device 91 executing the program stored in the storage device 94. In addition, you may implement | achieve the block which comprises the signal processing apparatus 13 by another structure.

  FIG. 3 is a block configuration diagram showing an example of functional blocks of the motion estimation device 34 in this embodiment.

  The motion estimation device 34 includes, for example, a signal input unit 41, an azimuth line dividing unit 42, a speed assumption unit 43, a correlation degree calculation unit 44, a correlation degree maximum speed determination unit 45, an approximate straight line calculation unit 50, The center determination unit 51, the movement speed calculation unit 52, the angular velocity calculation unit 53, and the motion output unit 54 are included.

The signal input unit 41 inputs the signal 82 before azimuth compression that has been subjected to range compression by the range compression unit 31 and the signal 84 that has been output by the target extraction unit 33. Based on the signal 84, the signal input unit 41 cuts out a signal corresponding to the portion extracted by the target extraction unit 33 from the input signal 82.
The reflection from the target 70 has a certain width in each of the azimuth direction and the range direction. The signal input unit 41 divides the signal 82 for each pulse 61 transmission cycle, and cuts out signals having a plurality of cycles that fall within a certain range in the azimuth direction distance. Further, the signal input unit 41 cuts out a signal of a portion that falls within a certain range in the range direction distance from the cut out signals of each cycle.

  The azimuth line dividing unit 42 divides the signal cut out by the signal input unit 41 into a plurality of parts (partial signals). The azimuth line dividing unit 42 is an example of a signal dividing unit. The azimuth line dividing unit 42 divides the signal cut out by the signal input unit 41 into azimuth lines. The azimuth line dividing unit 42 divides the signal extracted by the signal input unit 41 for each predetermined sampling period, and classifies the divided signal for each range direction distance. The azimuth line dividing unit 42 combines signals classified into the same range direction distance into one azimuth line. When the range of the range direction distance cut out by the signal input unit 41 corresponds to m times the sampling period, the azimuth line dividing unit 42 divides the signal cut out by the signal input unit 41 into m azimuth lines.

The speed assumption unit 43 assumes a plurality of speeds within a predetermined range as the speed of the target 70. For example, when the maximum value of the range direction speed 73 is set to v _{r, max} and the step size is set to Δv _r , the speed assumption unit 43 is greater than −v _{r, max} and less than v _{r, max} and is an integral multiple of Δv _r . V _r (−v _{r, max} ≦ v _r ≦ v _{r, max} , v _r = k _r · Δv _r , k _r is an integer) is assumed to be the range direction speed 73 of the target 70. Also, if you set the maximum value of azimuthal velocity 72 _{v a, max,} the step size in Delta] v _a, velocity assumption section _{43, -v a, max} above and _{v a,} with _max or less, an integral multiple of Delta] v _a suppose _{v a (-v a, max ≦} v a ≦ v a, max, v a = k a · Δv a, k is an integer.), and the azimuth direction velocity 72 of the target 70 is. Assume velocity _{v r} is _(2n r +1) pieces as the range direction velocity 73 of the target 70 (although, _{n r is, v r,} the maximum integer not exceeding _max / _{Δv r.),} Assumed as the azimuth direction velocity 72 velocity _{v a} is _(2n a +1) number (where, _{n a is, v a, max} / Delta] v _a maximum integer not exceeding.) since, it is assumed speed as the moving speed 71 of the speed assumption unit 43 the target 70 The number of v is (2n _r +1) × (2n _a +1), which is a combination of all of these.

The degree-of-correlation calculation unit 44 compresses each azimuth line divided by the azimuth line division unit 42 using a reference signal that matches each speed assumed by the speed assumption unit 43. When there are m azimuth lines divided by the azimuth line dividing unit 42 and n speeds assumed by the speed assumption unit 43, the correlation degree calculation unit 44 performs azimuth compression m × n times.
The correlation degree calculation unit 44 calculates the maximum value of the amplitude in each azimuth-compressed signal. The maximum value calculated by the correlation degree calculation unit 44 is referred to as “speed correlation degree”. When there are n speeds assumed by the speed assumption unit 43, the correlation degree calculation unit 44 calculates n speed correlation degrees for each azimuth line. When there are m azimuth lines divided by the azimuth line dividing unit 42, the correlation degree calculating unit 44 calculates m × n velocity correlation degrees in total.

The correlation degree maximum speed determination unit 45 determines the largest speed correlation degree from the speed correlation degrees calculated by the correlation degree calculation unit 44 for each of the azimuth lines divided by the azimuth line division unit 42. The correlation degree maximum speed determination unit 45 is an example of a partial speed estimation unit. The speed correlation degree determined by the correlation degree maximum speed determination unit 45 is referred to as “maximum correlation degree”.
The correlation degree maximum speed determination unit 45 sets the speed correlation degree calculated by the correlation degree calculation unit 44 to the maximum correlation degree from the speeds assumed by the speed assumption part 43 for each azimuth line divided by the azimuth line division part. Determine the speed to be. The speed determined by the correlation degree maximum speed determination unit 45 is referred to as “correlation degree maximum speed”. Since the speed correlation degree calculated by the correlation degree calculation unit 44 is a real number, it is assumed that the speed correlation degrees calculated by the correlation degree calculation unit 44 for different speeds are not completely equal. That is, the maximum correlation degree speed is determined to be one for one azimuth line.
If there are m azimuth lines divided by the azimuth line dividing unit 42, the correlation maximum speed determination unit 45 determines m maximum correlations and m correlation maximum speeds.

  Each azimuth line includes reflections from a portion of the target that has approximately the same range direction distance. Therefore, the maximum correlation degree speed calculated by the maximum correlation degree speed determination unit 45 represents the speed of each part obtained by dividing the target based on the range direction distance. Therefore, the maximum correlation degree speed is also referred to as “partial speed” for the azimuth line.

  The approximate straight line calculation unit 50 approximates the partial speed determined by the maximum correlation degree speed determination unit 45 for each azimuth line divided by the azimuth line division unit 42 as a function of the range direction distance corresponding to the azimuth line. calculate. For example, the approximate straight line calculation unit 50 calculates a coefficient of a linear function representing the approximate straight line. The approximate straight line calculation unit 50 is an example of a motion separation unit.

  For each azimuth line divided by the azimuth line dividing unit 42, the center determination unit 51 determines the maximum correlation degree speed determined by the correlation degree maximum speed determination unit 45 from the signals after azimuth compression performed by the correlation degree calculation unit 44. Get a signal about (partial velocity). The center determination unit 51 determines the center position of the target 70 based on the acquired signal. For example, the center determination unit 51 calculates a range in which the reflection from the target 70 is distributed in the range direction, and sets the center of the calculated range as the center position of the target 70 in the range direction.

  The movement speed calculation unit 52 calculates the movement speed of the entire target 70 based on the straight line calculated by the approximate straight line calculation unit 50. For example, the moving speed calculation unit 52 substitutes the speed calculated by substituting the range direction distance of the target 70 determined by the center determination unit 51 into a linear function represented by the coefficient calculated by the approximate straight line calculation unit 50. The moving speed.

  The angular velocity calculation unit 53 calculates the rotation speed of the target 70 itself based on the straight line calculated by the approximate straight line calculation unit 50. For example, the angular velocity calculation unit 53 determines the difference between the velocity at the center of the target 70 and the velocity at a position away from the center of the target 70 by a predetermined distance in the range direction based on the slope of the straight line calculated by the approximate line calculation unit 50. And the rotational speed of the target 70 itself is obtained based on the calculated difference.

  FIG. 4 is a diagram for explaining the operating principle of the motion estimation device 34 in this embodiment.

  The horizontal axis g indicates the ground range direction. The vertical axis z indicates the height direction. The azimuth direction is a direction perpendicular to the paper surface. The direction of the synthetic aperture radar 21 relative to the zenith as viewed from the target 70, that is, the incident angle of the pulse 61 transmitted by the synthetic aperture radar 21 is θ. The axis r indicates the range direction. The axis z 'indicates a direction perpendicular to the range direction (and azimuth direction).

Ground range of each portion of the target 70 - Height moving speed in the plane v _gz includes a moving velocity v _g of the overall target 70 to the ground range direction, the angular velocity around the vertical central axis 74 to the paper This is a combination with the velocity v _z resulting from the rotational motion of ω _gz .
Here, a relationship of v _z = ω _gz · Δg (where Δg represents a distance from the central axis 74) is established between the angular velocity ω _gz and the velocity v _z .

The range direction speed v _r that is the range direction component of the partial speed estimated by the correlation degree maximum speed determination unit 45 is the range direction component of the moving speed v _gz . Between the range direction velocity v _r and the moving velocity v _g and velocity v _z , v _r = v _g · sin θ−v _z · cos θ (wherein sin represents a sine function. Cos represents a cosine function. This represents the relationship.
Since v _z = ω _gz · Δg, v _r = v _g · sin θ−ω _gz · Δg · cos θ.
Also, Δr = Δg · sin θ (where Δr represents the distance from the central axis 74 in the range direction), so v _r = v _g · sin θ−ω _gz · Δr · cot θ (where cot is the cotangent) Represents a function).
That is, there is a relationship represented by the straight line L ₁ : v _r = a ₁ · r + b ₁ between the range direction velocity v _r and the range direction distance r.
Since there is actually an influence of an observation error, the approximate line calculation unit 50 calculates the coefficients a ₁ and b ₁ of the linear function a ₁ · r + b ₁ representing the straight line L ₁ using, for example, the least square method. .

Moving velocity v _g of the target 70 whole ground range direction is, for example, be calculated as follows.
The moving speed calculation unit 52 calculates the range direction speed v _ro in the central axis 74 based on the values of the coefficients a ₁ and b ₁ calculated by the approximate straight line calculation unit 50 and the range direction distance r ₀ of the central axis 74. To do. The moving speed calculation unit 52 calculates a value a ₁ · r ₀ + b ₁ obtained by adding the coefficient b ₁ to the product a ₁ · r ₀ of the coefficient a ₁ and the range direction distance r ₀ to obtain the range direction speed v _ro. And
Since Δr = 0 on the central axis 74, v _ro = v _g · sin θ. Moving speed computing unit 52, the range direction velocity v _ro the calculated, based on the incident angle theta, and calculates the moving velocity v _g of the ground range direction of the entire target 70. The moving speed calculation unit 52 calculates a quotient v _ro / sin θ obtained by dividing the range direction speed v _ro by the sine sin θ of the incident angle θ to obtain the moving speed v _g of the entire target 70 in the ground range direction.

Further, the angular velocity ω _gz of the target 70 itself in the ground range-height plane is calculated as follows, for example.
The moving speed calculation unit 52 calculates the angular velocity ω _gz based on the coefficient a ₁ calculated by the approximate line calculation unit 50 and the incident angle θ. The moving speed calculation unit 52 calculates the product a ₁ · tan θ of the tangent tan θ of the incident angle θ and the coefficient a _1, and reverses the positive / negative sign to obtain the angular speed ω _gz .

  FIG. 5 is a diagram for explaining the operating principle of the motion estimation device 34 in this embodiment.

  The horizontal axis g indicates the ground range direction. The vertical axis a indicates the azimuth direction. The height direction is a direction perpendicular to the paper surface.

The movement speed v _aω in the horizontal plane of each part of the target 70 is the movement speed v _{ao in} the azimuth direction of the entire target 70 and an angular speed ω _ga centered on an axis perpendicular to the paper surface passing through the center point 75. This is a combination with the velocity v _ω resulting from the rotational motion.
Azimuth direction velocity v _a is the azimuth direction component of the partial rate of correlation maximum speed determining unit 45 has estimated a azimuth direction component of the moving velocity v _Aw. And azimuth direction velocity _{v a,} between the moving velocity _{v ao} and velocity v _{omega is,} v _{a = v} holds relationship ao + v ω · _cosφ.
Here, the angular velocity omega _ga, between the velocity _{v ω, v ω = ω ga} · Δg / cosφ ( although, Delta] g is .Fai representing the distance from the center point 75 in ground range direction is the center point This represents the angle with respect to the ground range direction as viewed from 75.)

Thus, the azimuth direction velocity _{v a} is estimated from observations by the synthetic aperture radar 21, between the moving velocity _{v ao} and the angular velocity omega _{ga is, v a = v ao + ω} ga · Δr / sinθ ( although, [Delta] r is Represents the distance from the center point 75 in the range direction). This relationship does not depend on the angle φ.
Since the correlation degree maximum speed determination unit 45 estimates the movement speed based on the azimuth line, for example, the azimuth direction speed is calculated without distinguishing the portion in the region surrounded by the broken line 77. If the range direction distance is the same, the azimuth direction speed is the same regardless of the positional relationship with the center point 75, so the azimuth direction speed estimated by the correlation degree maximum speed determination unit 45 is any of the areas enclosed by the broken line 77. It is not necessary to determine whether the speed is the azimuth direction speed of the point or the average of the azimuth direction speeds of a plurality of points.

Between the azimuth direction velocity _{v a} and range direction distance r linearly _{L 2:} v relationship represented by _{a = a 2 · r + b} 2.
Since there is actually an influence of an observation error, the approximate line calculation unit 50 calculates the coefficients a ₂ and b ₂ of the linear function a ₂ · r + b ₂ representing the straight line L ₂ using, for example, the least square method. .

The moving speed _{vao in} the azimuth direction of the entire target 70 is calculated as follows, for example.
The moving speed calculation unit 52 calculates the azimuth direction speed at the center point 75 based on the values of the coefficients a ₂ and b ₂ calculated by the approximate line calculation unit 50 and the range direction distance r ₀ of the center point 75. , The moving speed v _{ao in} the azimuth direction of the entire target 70 is set. The moving speed calculation unit 52 calculates a value a ₂ · r ₀ + b ₂ obtained by adding the coefficient b ₂ to the product a ₂ · r ₀ of the coefficient a ₂ and the range direction distance r ₀ to obtain the azimuth direction velocity v _ao. And

Further, the angular velocity _ωga in the horizontal plane of the target 70 itself is calculated as follows, for example.
Moving speed computing unit 52, the coefficient a ₂ of the approximate line calculation unit 50 is calculated, based on the incident angle theta, calculates an angular velocity omega _ga. The moving speed calculation unit 52 calculates a product a ₂ · sin θ of the sine sin θ of the incident angle θ and the coefficient a ₂ to obtain an angular speed ω _ga .

  FIG. 6 is a flowchart showing an example of the flow of the motion estimation process S10 in this embodiment.

  In the motion estimation process S10, the motion estimation device 34 estimates the moving speed of the entire target 70 and the angular speed of the target 70 itself. The motion estimation process S10 includes, for example, an azimuth line selection step S11, a maximum correlation degree initialization step S12, an assumed speed selection step S13, a correlation degree calculation step S14, an approximate straight line calculation step S15, and a center determination step S17. The moving speed calculating step S18 and the angular velocity calculating step S19 are included.

  The motion estimation device 34 selects the azimuth lines divided by the azimuth line dividing unit 42 one by one, and estimates the speed of the portion of the target 70 corresponding to the azimuth line.

In the azimuth line selection step S11, the azimuth line dividing unit 42 selects one azimuth line from among the plurality of divided azimuth lines.
If all the azimuth lines have been selected and there is no azimuth line that has not been selected, the azimuth line dividing unit 42 proceeds to the approximate straight line calculation step S15.
If there is an azimuth line that has not yet been selected, the azimuth line dividing unit 42 selects one azimuth line from among the azimuth lines that have not yet been selected, and proceeds to the maximum correlation degree initialization step S12.

  In the maximum correlation degree initialization step S12, the correlation degree maximum speed determination unit 45 initializes the maximum correlation degree and the correlation degree maximum speed. For example, the correlation maximum speed determination unit 45 stores 0 as the initial value of the maximum correlation.

  The motion estimation device 34 selects a speed one by one from a plurality of speeds, and the selected speed corresponds to the portion of the target 70 corresponding to the azimuth line selected by the azimuth line dividing unit 42 in the azimuth line selection step S11. The maximum correlation degree and the maximum correlation degree speed are obtained by calculating the speed correlation degree on the assumption of the speed.

In the assumed speed selection step S13, the speed assumption unit 43 selects one speed that has not yet been selected from a plurality of predetermined speeds.
When all the speeds have been selected and there is no speed that has not yet been selected, the correlation degree maximum speed determination unit 45 divides the stored temporary value of the correlation degree maximum speed in the azimuth line selection step S11. The partial speed for the azimuth line selected by the unit 42 is used. The azimuth line dividing unit 42 returns the process to the azimuth line selection step S11 and selects the next azimuth line.
If there is a speed that has not yet been selected, the speed assumption unit 43 selects one speed from the speeds that have not yet been selected, and proceeds to the correlation degree calculation step S14.

In the correlation calculation step S14, the correlation calculation unit 44 determines that the speed selected by the speed assumption unit 43 in the assumed speed selection step S13 corresponds to the azimuth line selected by the azimuth line division unit 42 in the azimuth line selection step S11. Assuming a rate of 70 parts, a reference signal is generated. The correlation calculation unit 44 azimuth-compresses the azimuth line selected by the azimuth line dividing unit 42 in the azimuth line selection step S11 using the generated reference signal. The correlation degree calculation unit 44 sets the maximum value of the amplitude of the azimuth-compressed signal after azimuth compression as the speed correlation degree.
The correlation degree maximum speed determination unit 45 compares the stored maximum correlation degree with the speed correlation degree calculated by the correlation degree calculation unit 44. When the speed correlation degree calculated by the correlation degree calculation unit 44 is larger, the correlation degree maximum speed determination unit 45 stores the speed correlation degree calculated by the correlation degree calculation unit 44 as the maximum correlation degree. The correlation degree maximum speed determination unit 45 stores the speed selected by the speed assumption unit 43 in the assumed speed selection step S13 as a provisional value of the correlation degree maximum speed.
The speed assumption unit 43 returns the process to the assumed speed selection step S13, and selects the next speed.

In the approximate straight line calculation step S15, the approximate straight line calculation unit 50 sets the range direction component of the partial speed based on the partial speed calculated by the correlation degree maximum speed determination unit 45 for each azimuth line divided by the azimuth line division unit 42. the straight line L ₁ be approximated as a function of the direction distance, it calculates a straight line L ₂ which approximates the azimuth direction component of the partial rate as a function of range direction distance.

  In the center determination step S17, the center determination unit 51 determines the center point 75 of the rotation of the target 70 itself. The center determination unit 51 calculates the range direction distance between the center axis 74 and the center point 75. If the central axis 74 passes through the central point 75, the range direction distance of the central axis 74 and the range direction distance of the central point 75 are the same.

In the moving velocity calculation step S18, the moving velocity calculation unit 52, approximated straight line L ₁ to the approximate line calculation unit 50 is calculated by the straight line calculating step S15, the range of center determining step S17 the central axis 74 of the central determination unit 51 is calculated by based on the direction distance, to calculate the ground range direction velocity v _g of the overall target 70.
Moving speed computing unit 52, the straight line L ₂ of the approximate line calculation unit 50 is calculated by the approximation line calculating step S15, based on the range direction distance between the center point 75 of central determination unit 51 in the center determining step S17 is calculated, The azimuth direction velocity _vao of the entire target 70 is calculated.
The motor output unit 54 outputs the ground range direction velocity v _g of the moving velocity calculation unit 52 calculates a signal representing the azimuth direction velocity v _ao.

Calculating an angular velocity omega _gz at the height plane - an angular velocity calculation step S19, the angular velocity calculating section 53, based on the straight line L ₁ to the approximate line calculation unit 50 is calculated by the approximation line calculating step S15, the target 70 itself ground range To do.
Angular velocity calculating section 53, an approximate line calculation unit 50 in the approximate straight line calculating step S15 based on the straight line L ₂ calculated, calculates an angular velocity omega _ga at the target 70 itself in the horizontal plane.
The motion output unit 54 outputs a signal representing the angular velocity ω _gz in the ground range-height plane calculated by the angular velocity calculating unit 53 and the angular velocity ω _ga in the horizontal plane.

  Thus, by separating the motion of the entire target 70 and the rotational motion of the target 70 itself, the moving speed due to the motion of the entire target 70 can be correctly estimated.

  Since the moving speed of the entire target 70 can be correctly estimated, it is possible to automate the focusing of the image generated based on the observation result by the synthetic aperture radar 21.

  When the moving speed of the entire target 70 cannot be estimated correctly, the image generated based on the observation result by the synthetic aperture radar 21 is out of focus, resulting in an unclear image. In such a case, for example, when a human sees the generated image, it is determined whether or not the image is clear. If it is determined that the image is not clear, a manual operation such as instructing the re-estimation of the moving speed of the target 70 is performed. I need it.

  Since the motion estimation device 34 correctly estimates the moving speed of the entire target 70, the signal processing device 13 can generate a clear image mechanically and automatically without the need for manual work.

The method in which the azimuth line dividing unit 42 divides the signal 82 before azimuth compression is not limited to the method of dividing the signal 82 into azimuth lines, and other methods may be used. However, it is desirable that the azimuth line dividing unit 42 divides long in the azimuth direction and short in the range direction.
This is because when the target 70 itself is rotating in a horizontal plane, the azimuth direction velocity is determined by the range direction distance regardless of the azimuth direction distance. Further, when the target 70 itself is rotating in the ground range-height plane, the range direction speed is determined by the range direction distance regardless of the azimuth direction distance.
Therefore, if the division is made long in the azimuth direction and short in the range direction, the variation in the speed of the portion of the target 70 included in each divided signal becomes small, and the estimation accuracy becomes high.

  Further, by separating the motion of the entire target 70 and the rotational motion of the target 70 itself, not only the moving speed due to the motion of the entire target 70 but also the angular velocity due to the rotational motion of the target 70 itself can be correctly estimated. .

  The angular velocity due to the rotational motion of the target 70 itself can be used as follows, for example.

  Prediction of the direction of travel of the target 70. Rotating the target 70 itself in the horizontal plane often means turning the target 70. Therefore, if the rotation of the target 70 itself in the horizontal plane is known, a change in the traveling direction of the target 70 can be predicted.

  Estimation of target 70 mass. Rotation of the target 70 itself in the vertical plane often means that the target 70 is swinging. If the angular velocity of the target 70 in the vertical plane is large, it can be estimated that the vibration frequency is high and the target 70 is light. Conversely, if the angular velocity of the target 70 in the vertical plane is small, it can be estimated that the vibration frequency is low and the target 70 is heavy. Thereby, for example, it can be determined whether the target 70 is in an empty state or a full load state.

The signal processing apparatus in this embodiment uses a refocus ISAR (Inverse Synthetic Aperture Radar) to extract a target velocity vector for each azimuth line and estimate a target rotational motion.
The angular velocity in the target horizontal plane (yaw direction) is estimated by combining the velocity vectors in the azimuth direction. Further, the angular velocity in the target ground range-height plane (pitch direction or roll direction) is estimated by combining speed vectors in the range direction. Furthermore, the target highly accurate speed is estimated by using the approximate straight line at the time of angular speed extraction.

  Since it is possible to estimate the rotational motion and the highly accurate speed of the target, it is possible to perform a detailed analysis of the moving body.

Embodiment 2. FIG.
The second embodiment will be described with reference to FIGS.
In addition, about the part which is common in Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  FIG. 7 is a block configuration diagram showing an example of functional blocks of the motion estimation device 34 in this embodiment.

  The motion estimation device 34 includes a rotation calculation unit 49 instead of the approximate straight line calculation unit 50 described in the first embodiment.

  The rotation calculation unit 49 calculates the rotation axis and angular velocity of the rotational movement of the target 70. Note that the rotational motion of the target 70 calculated by the rotation calculation unit 49 includes not only the rotational motion of the target 70 itself but also the motion of the entire target 70.

For example, the rotation calculation unit 49 performs the rotational motion of the target 70 in a three-dimensional coordinate space including a range direction axis r, an azimuth direction axis a, and an axis z ′ orthogonal to both the range direction axis and the azimuth direction axis. For the rotation axis, a unit vector (q _r , q _a , q _{z ′} ) representing the direction of the rotation axis and coordinates (r _x , a _x , z ′ _x ) of the position closest to the origin on the rotation axis are used. To express. From the definition, the following equation holds.

q _r ² + q _a ² + q _{z ′} ² = 1
_{q r · r x + q a} · a x + q z '· z' x = 0

  There are seven unknowns including the angular velocity ω, and the degree of freedom is five.

ただし、Ｐ（ｔ）は、ｔ＝０のとき座標（ｒ，ａ，ｚ’）にあった点のｔ秒後の位置を表わす四元数であり、Ｐ（０）＝（０；ｒ，ａ，ｚ’）である。Ｒ（ｔ）は、回転を表わす四元数であり、次の式で表わされる。

また、上に横棒を付したＲ（ｔ）は、Ｒ（ｔ）の共役四元数を表わす。・は、四元数の乗算を表わす。 The position after t seconds of the point of coordinates (r, a, z ′) can be expressed by the following equation.

However, P (t) is a quaternion representing the position after t seconds of the point at the coordinates (r, a, z ′) when t = 0, and P (0) = (0; r, a, z ′). R (t) is a quaternion representing rotation and is represented by the following equation.

R (t) with a horizontal bar on it represents the conjugated quaternion of R (t).・ Represents quaternion multiplication.

By differentiating P (t) with respect to t and substituting t = 0, the moving speed (v _r , v _a , v _{z ′} ) of the point of coordinates (r, a, z ′) at t = 0 is obtained. Can be sought. From this, the following equation holds.

The rotation calculating unit 49 calculates the range direction distance r corresponding to each azimuth line divided by the azimuth line dividing unit 42.
Further, the rotation calculation unit 49 is a signal regarding the maximum correlation degree speed (partial speed) determined by the correlation degree maximum speed determination unit 45 among the plurality of azimuth-compressed signals compressed by the correlation degree calculation unit 44. The position where the velocity correlation degree is maximized is determined, and the azimuth direction distance a corresponding to the position is calculated. The azimuth direction distance a is the position in the azimuth direction where the amplitude is maximum in the signal after azimuth compression using the reference signal based on the speed at which the velocity correlation degree is maximum for the azimuth line.
The distance z ′ in the z′-axis direction cannot be calculated and is therefore unknown. Rotation calculation unit 49, the range direction velocity v _r and the azimuth direction velocity v _a, use the partial rate of degree of correlation maximum speed determining unit 45 determines. However, the velocity v _{z ′} in the z′-axis direction is unknown.
Therefore, for each azimuth line, equations for v _r and v _a are established and z ′ is added to the unknown. The formula for v _{z ′} is not used. That is, every time the azimuth line increases by one, the number of equations increases by two and the number of unknowns increases by one.

Therefore, if there are five azimuth lines divided by the azimuth line dividing unit 42, the number of equations is equal to 12 and the number of unknowns is equal to 12, so that all unknowns can be obtained by solving simultaneous equations. However, there are normally six or more azimuth lines divided by the azimuth line dividing unit 42, and there is a possibility that no solution exists. Therefore, the rotation calculation unit 49 obtains the unknown using, for example, a least square method.
For example, the rotation calculation unit 49 calculates the rotation axis, the angular velocity, and the z′-axis coordinates of each point so that the sum of squares of the errors of the range direction velocity v _r and the azimuth direction velocity v _a of each point is minimized.

  The center determination unit 51 determines the center point of the target 70 based on the coordinates of each point calculated by the rotation calculation unit 49. For example, the center determination unit 51 sets a point obtained by averaging the coordinates of each point as the center point of the target 70.

  The movement speed calculation unit 52 calculates the movement speed of the entire target 70 based on the rotational motion calculated by the rotation calculation unit 49 and the center point calculated by the center determination unit 51. For example, the moving speed calculation unit 52 calculates the moving speed of the center point of the target 70 and sets it as the moving speed of the entire target 70.

  The angular velocity calculation unit 53 calculates the rotational motion of the target 70 itself in a predetermined plane based on the rotational motion calculated by the rotation calculation unit 49. For example, the angular velocity calculator 53 converts the rotational motion calculated by the rotation calculator 49 into an angular velocity in the horizontal plane of the target 70, an angular velocity in the ground range-height plane, and an angular velocity in the azimuth-height plane. .

  FIG. 8 is a flowchart showing an example of the flow of the motion estimation process S10 in this embodiment.

  The motion estimation process S10 does not include the approximate straight line calculation step S15 among the steps described in the first embodiment, but includes a rotation calculation step S16 instead. Note that description of steps similar to those described in Embodiment 1 is omitted.

  In the maximum correlation degree initialization step S12, the rotation calculation unit 49 initializes the range direction distance and the azimuth direction distance of the point corresponding to the azimuth line selected by the azimuth line division unit 42 in the azimuth line selection step S11. For example, the rotation calculation unit 49 calculates the range direction distance of the azimuth line and stores it as the range direction distance of the point corresponding to the azimuth line.

  In the correlation calculation step S14, when the velocity correlation is larger than the temporarily stored maximum correlation, the rotation calculation unit 49 determines that the amplitude of the azimuth-compressed signal obtained by the correlation calculation unit 44 is azimuth-compressed. The azimuth direction distance corresponding to the maximum position is calculated. The rotation calculation unit 49 stores the calculated azimuth direction distance as the azimuth direction distance of the point corresponding to the azimuth line.

  In the rotation calculation step S <b> 16, the rotation calculation unit 49 regards the partial speed calculated by the correlation degree maximum speed determination unit 45 for each azimuth line as the moving speed of the point corresponding to the azimuth line, and sets the target 70. Calculate the rotational motion.

  In the center determination step S17, the center determination unit 51 determines the center point of the rotational motion of the target 70 itself based on the rotational motion calculated by the rotation calculation unit 49 in the rotation calculation step S16.

  Thus, assuming that the target 70 is a rigid body, the rotational motion of the target 70 is estimated from the position and speed of each point of the target 70. Thereby, even when the height of the target 70 and the moving speed in the height direction are unknown, the moving speed and angular velocity of the target 70 can be correctly estimated.

The rotation calculation unit 49 may be configured to weight each point and calculate the rotational motion of the target 70 by the least square method. For example, the rotation calculation unit 49 sets the maximum correlation degree of each azimuth line as the weight w of the point extracted from the azimuth line. Rotation calculation unit 49, so that the product sum of multiplied by weight w to the square of the error in the range direction velocity v _r and the azimuth direction velocity v _a of each point is minimized, the rotation axis and the angular velocity and z 'coordinates of each point Is calculated.

  In addition, when there are a plurality of signal peaks in one azimuth line, the rotation calculation unit 49 not only detects the position of the point corresponding to the position where the amplitude of the signal after azimuth compression is maximized (azimuth direction distance), but also all the peaks. The configuration may be such that the position of the point corresponding to the peak is calculated. In this case, for example, the correlation degree calculation unit 44 does not calculate one maximum correlation degree speed for one azimuth line, but calculates a speed at which the peak is maximum for each peak. The rotation calculation unit 49 calculates the rotational axis and angular velocity of the rotational motion of the target 70 by using the speed calculated by the correlation degree calculation unit 44 for each peak as the speed at that point.

  As described above, the configuration described in each embodiment is an example, and another configuration may be used. For example, the structure which combined the structure demonstrated in different embodiment may be sufficient, and the structure which replaced the structure of the non-essential part with the other structure may be sufficient.

The motion estimation device (34) described above includes a partial speed estimation unit (maximum correlation degree speed determination unit 45), a motion separation unit (approximate straight line calculation unit 50), and a movement speed calculation unit (52).
The partial velocity estimation unit calculates the moving speed of the portion for each of a plurality of portions obtained by dividing the target (70) observed by the synthetic aperture radar based on the signal (81) output by the synthetic aperture radar (21). presume.
The motion separation unit separates the motion of the entire target and the rotational motion of the target itself based on the speed estimated by the partial speed estimation unit for each of the plurality of portions.
The movement speed calculation unit calculates a movement speed due to the movement of the entire target based on the movement of the entire target separated by the movement separation unit.

  The movement speed of the entire target is separated from the rotational movement of the target itself, and the movement speed due to the movement of the entire target is calculated. it can.

The partial speed estimation unit (45) divides the target (70) into the plurality of parts based on the distance in the range direction.
The motion separation unit (50) calculates a linear function that approximates the moving speed estimated by the partial speed estimation unit for each of the plurality of parts as a function of the distance in the range direction.
The moving speed calculation unit (52) calculates a moving speed of a portion that is the center of the target (70) based on the linear function calculated by the motion separating unit, To do.

  By approximating the moving speed with a linear function as a function of the distance in the range direction, the motion of the entire target is reflected in the constant term, and the rotational motion of the target itself is reflected in the coefficient of the primary term. Thereby, the motion of the whole target and the rotational motion of the target itself can be separated.

The motion estimation device (34) further includes a signal dividing unit (azimuth line dividing unit 42).
The signal dividing unit divides the signal (82) before azimuth compression based on the signal (81) output from the synthetic aperture radar (21) into a plurality of partial signals (azimuth lines) based on the distance in the range direction. .
The partial speed estimation unit (45) estimates the moving speed of the part of the target (70) corresponding to the partial signal based on each of the plurality of partial signals divided by the signal division unit.

  By dividing the signal before azimuth compression based on the distance in the range direction, the target portion whose reflection is included in the partial signal is divided based on the distance in the range direction. Thereby, the variation in the speed of the target portion is reduced, and the estimation accuracy of the moving speed of the entire target and the angular speed of the target itself is increased.

  The moving speed calculation unit (52) calculates the moving speed in the range direction due to the movement of the entire target, assuming that the entire target (70) does not move in the height direction, and calculates the calculated range direction. The movement speed of is converted to the movement speed in the ground range direction.

  Thereby, for example, it is possible to accurately estimate the moving speed of a ship that navigates the sea, a vehicle that travels on a road with a small gradient, and the like.

The motion estimation device (34) further includes an angular velocity calculation unit (53).
The angular velocity calculation unit calculates an angular velocity due to the rotational motion of the target itself based on the rotational motion of the target (70) itself separated by the motion separation unit (50).

  Thereby, the advancing direction of a target can be estimated or the mass of a target can be estimated.

  The angular velocity calculation unit (53) is based on a change rate of a difference between the movement velocity estimated by the partial velocity estimation unit (45) for each of the plurality of portions and the movement velocity due to the movement of the entire target (70). The angular velocity due to the rotational motion of the target itself is calculated.

  Thereby, the angular velocity by the rotational motion of the target itself can be calculated with high accuracy.

The signal processing device (13) described above is
The motion estimation device (34);
Assuming that the moving speed of the entire target (70) estimated by the motion estimation device is the target speed, before the azimuth compression based on the signal (81) output by the synthetic aperture radar (21). The azimuth compression part (second azimuth compression part 35) which compresses the signal (82) of azimuth.

  Since the motion estimation device accurately estimates the target moving speed, the resolution in the azimuth direction can be increased.

  Since the present invention specifically performs information processing based on the physical property or technical property of the target (synthetic aperture radar), it is a creation of a technical idea utilizing the laws of nature.

  DESCRIPTION OF SYMBOLS 10 Synthetic aperture radar observation system, 12 Observation satellite, 13 Signal processing apparatus, 21 Synthetic aperture radar, 31 Range compression part, 32 1st azimuth compression part, 33 Target extraction part, 34 Motion estimation apparatus, 35 2nd azimuth compression part, 36 image generation unit, 37 additional information generation unit, 41 signal input unit, 42 azimuth line division unit, 43 speed assumption unit, 44 correlation degree calculation unit, 45 correlation degree maximum speed determination unit, 49 rotation calculation unit, 50 approximate line calculation Part, 51 center determination part, 52 movement speed calculation part, 53 angular velocity calculation part, 54 motion output part, 61 pulse, 62 reflected wave, 70 target, 71 movement speed, 72 azimuth direction speed, 73 range direction speed, 74 center axis 75 center point, 76 speed, 77 broken line, 81-86 signal, 91 processing device, 92 input device, 93 output device 94 storage device, S10 motion estimation process, S11 azimuth line selection step, S12 maximum correlation degree initialization step, S13 assumed speed selection step, S14 correlation degree calculation step, S15 approximate line calculation step, S16 rotation calculation step, S17 center determination step , S18 Movement speed calculation step, S19 Angular velocity calculation step.

Claims (9)

A partial speed estimation unit, a motion separation unit, and a movement speed calculation unit;
The partial velocity estimation unit estimates the moving speed of the portion for each of a plurality of portions obtained by dividing the target observed by the synthetic aperture radar based on the signal output by the synthetic aperture radar,
The motion separation unit separates the motion of the entire target and the rotational motion of the target itself based on the speed estimated by the partial speed estimation unit for each of the plurality of portions.
The movement estimation device, wherein the movement speed calculation unit calculates a movement speed due to the movement of the entire target based on the movement of the entire target separated by the movement separation unit. The partial speed estimation unit divides the target into the plurality of parts based on the distance in the range direction,
The motion separation unit calculates a linear function that approximates the moving speed estimated by the partial speed estimation unit for each of the plurality of parts as a function of the distance in the range direction,
The moving speed calculating unit calculates a moving speed of a portion that is the center of the target based on the linear function calculated by the motion separating unit, and sets the moving speed by the movement of the entire target. The motion estimation apparatus according to claim 1. The motion estimation apparatus further includes a signal dividing unit,
The signal dividing unit divides the signal before azimuth compression based on the signal output from the synthetic aperture radar into a plurality of partial signals based on the distance in the range direction,
The said partial speed estimation part estimates the moving speed of the said target part corresponding to the said partial signal based on each of the some partial signal which the said signal division part divided | segmented, The Claim 2 characterized by the above-mentioned. Motion estimation device.   The moving speed calculation unit calculates the moving speed in the range direction due to the movement of the entire target, assuming that the entire target does not move in the height direction, and calculates the moving speed in the range direction to the ground range. The motion estimation apparatus according to claim 1, wherein the motion estimation apparatus converts the movement speed in a direction. The motion estimation device further includes an angular velocity calculation unit,
The angular velocity calculation unit calculates an angular velocity due to the rotational motion of the target itself based on the rotational motion of the target itself separated by the motion separation unit. The motion estimation apparatus described.   The angular velocity calculation unit is configured to determine an angular velocity due to the rotational motion of the target itself based on a change rate of a difference between the movement velocity estimated by the partial velocity estimation unit for each of the plurality of portions and the movement velocity due to the motion of the entire target. The motion estimation apparatus according to claim 5, wherein: The motion estimation device according to any one of claims 1 to 6,
An azimuth compression unit that compresses a signal before azimuth compression based on a signal output from the synthetic aperture radar on the assumption that the moving speed of the entire target estimated by the motion estimation device is the target speed. And a signal processing device.   A computer program that, when executed by a computer, causes the computer to function as the motion estimation device according to any one of claims 1 to 6 or the signal processing device according to claim 7. In the motion estimation method for estimating the motion of the target observed by the synthetic aperture radar based on the signal output by the synthetic aperture radar,
Based on the signal output by the synthetic aperture radar, for each of a plurality of portions obtained by dividing the target observed by the synthetic aperture radar, the moving speed of the portion is estimated,
Based on the speed estimated for each of the plurality of parts, the overall movement of the target and the rotational movement of the target itself are separated,
A motion estimation method, wherein a movement speed due to the motion of the entire target is calculated based on the separated motion of the entire target.

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