JP2001141820A - Image radar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image radar in which the motion of a target can be determined. SOLUTION: The image radar comprises means 21 for acquiring the radar image of a target continuously, means 22 for obtaining the speed distribution of bright point on a radar image based on the positional variation thereof by comparing two continuous radar images, a data base 23 prestoring the shape of a plurality of targets, means 24 for making the bright point on the radar image to correspond with the shape of target in the shape data base 24, and means 25a, 26a, 27 for estimating the motion of the target based on the radar image, the speed distribution and the shaper of the target.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image radar apparatus for observing a distant target and obtaining a radar image of the target, and more particularly to an image radar apparatus capable of obtaining a target motion.

[0002]

2. Description of the Related Art FIG. 17 is a block diagram of a conventional radar device described in, for example, Japanese Patent No. 2738244. In FIG. 17, 1 is a transmitter, 2 is a receiver, 3 is a transmission / reception switch, 4 is a transmission / reception antenna, 5 is an image reproducing means, 6
Is a correlation calculating means, 7 is a target tracking means, 8 is a point image response estimating means, 9 is a target aspect angle estimating means, 10 is an RCS calculating means, 11 is a target shape data accumulating means, 12 is a convolution integrating means, and 13 is a maximum. The value detection means 14 is a target identification result output means.

FIGS. 18 and 19 are diagrams for explaining the geometry of observation by the conventional radar apparatus. In the figure, 4 is a transmitting / receiving antenna, and 19 is a target.

FIG. 20 is a block diagram showing a detailed configuration of the image reproducing means 5 of FIG. In FIG.
15 is a range compression means, 16 is a motion compensation means, 17 is a cross range compression means, and 18 is a two-dimensional storage means.

Next, the operation will be described. The high-frequency signal generated by the transmitter 1 is radiated from the transmission / reception antenna 4 to the target 19 via the transmission / reception switch 3. A part of the high-frequency signal applied to the target 19 is reflected by the target 19 and received again by the transmission / reception antenna 4, and passes through the transmission / reception switch 3 to the receiver 2.
After amplification and detection by the image reproducing means 5, the radio wave scattering cross section (RCS: Radar Cross Sectio
n) Converted to a radar image representing the distribution. Hereinafter, a method of reproducing an image will be described in detail.

[0006] The received signal output from the receiver 2 is input to the image reproducing means 5, and first, processing for improving the range resolution, that is, pulse compression is performed by the range compressing means 15. The received signal after range compression is stored in the two-dimensional storage means 18 according to the range bin number m and the pulse hit number n. In order to remove random components harmful to image reproduction from the movement of the target 19, the received signal is stored in the two-dimensional storage unit 1.
8, phase compensation and rearrangement of range bins are performed by the motion compensating means 16 so that the Doppler frequency of the center point 20 of the target 19 becomes zero, and stored in the two-dimensional storage means 18 again.

Now, as shown in FIG. 18, if it is assumed that the target 19 is rotated by a turning motion, different points on the target existing in the same range bin generate reflected waves having different Doppler frequencies. Goal 19
Similarly, different points on the target present in the same range bin will produce reflected waves of different Doppler frequencies, even if is moving straight. This is shown in FIG.
It can be understood that the motion shown in FIG. 19A is equivalent to the motion shown in FIG.

Using this, the cross range compression means 17
Uses the FFT (Fast)
By performing Fourier Transform, the resolution of a cross range that is a direction orthogonal to the range is improved. Through these processes, the resolution of the received signal is increased in both the range and cross-range directions, and the received signal is converted into a radar image representing the RCS distribution of each point on the target.

On the other hand, the means from the target tracking means 7 to the convolution integration means 12 generate pseudo radar images of various targets under given observation conditions. Although not described in detail because it is not directly related to the present invention, the target tracking means 7 calculates the speed of the target 19, the point image response estimating means 8 calculates the point image response of the radar image, and the target aspect angle estimating means 9 Estimate the target aspect angle. The RCS calculating means 10 calculates a target RCS distribution using the target three-dimensional shape stored in the target shape data accumulating means 11, and the convolution integrator 12 performs convolution integration of the point image response on the RCS distribution. Generate a pseudo radar image for collation.

The correlation calculating means 6 calculates a correlation value between the radar image and the pseudo radar image which is sequentially generated, and the maximum value detecting means 13 detects a maximum value among the sequentially calculated correlation values. Then, the target identification result output means 14 reads target information corresponding to the dictionary image having the maximum correlation value, for example, a shape and a name from the target shape data storage means 11 and outputs the read information. Achieve automatic goal identification.

[0011]

A conventional radar device is:
With the above-described configuration, the target can be identified, but the movement of the target cannot be known.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide an image radar apparatus capable of obtaining a target motion.

[0013]

According to the present invention, there is provided an image radar apparatus for observing a target and obtaining the radar image, comprising: a continuous image obtaining means for continuously obtaining a target radar image; Comparing the radar images,
Velocity distribution acquisition means for obtaining a velocity distribution of a luminescent spot based on a change in the position of a luminescent spot on a radar image; a shape database in which a plurality of target shapes are stored in advance; And a motion estimating means for obtaining a target motion from a radar image, a velocity distribution, and a target shape.

Further, the apparatus further comprises a feedback loop from the motion estimating means to the corresponding means, and when the output of the motion estimating means does not satisfy the predetermined condition, the corresponding means re-associates with the target shape.

The motion estimating means includes attitude estimating means for obtaining a target attitude based on the positional relationship of the bright spots on the radar image in the range direction.

The motion estimating means has an angular velocity estimating means for obtaining a target rotational angular velocity based on a positional relationship of a bright spot on the radar image in a cross range direction.

Tracking means for obtaining the target moving speed; distance measuring means for measuring the distance to the target; and angular velocity correcting means for correcting the rotational angular velocity of the target based on the target moving speed and the distance to the target. Is further provided.

The motion estimating means has an angular acceleration estimating means for obtaining a target rotational angular acceleration based on a changing speed of a bright spot on the radar image in a cross range direction.

Tracking means for obtaining the moving speed of the target; distance measuring means for measuring the distance to the target; and angular acceleration correcting means for correcting the rotational angular acceleration of the target based on the moving speed and the distance to the target. Is further provided.

The shape database stores at least three radio wave scatterers having different radio wave scattering cross-sectional areas of each target as a target shape, and the corresponding means stores at least three bright spots on the radar image in the shape database. Correlate with the target shape.

Further, the shape database stores a plurality of dense radio wave scatterers of each target as a target shape, and the corresponding means stores a plurality of dense luminescent spots on the radar image with the target shape of the shape database. Correspond.

Further, the shape database stores the radio wave scatterers distributed in different numbers at at least three places of each target as the target shape, and the corresponding means stores the different numbers of radio wave scatterers in at least three places on the radar image. The distributed bright spots are associated with target shapes in the shape database.

Further, the shape database stores the distribution pattern of the radio wave scatterers of each target as the target shape, and the correspondence unit associates the distribution pattern of the bright spots on the radar image with the target shape in the shape database.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram showing an image radar apparatus according to the present invention. In FIG. 1, 1 is a transmitter, 2 is a receiver, 3 is a transmission / reception switch, 4 is a transmission / reception antenna, and 5 is an image reproducing means. These are the same as or equivalent to the conventional radar device shown in FIG.

Reference numeral 21 denotes an image delaying means as an image continuous obtaining means for continuously obtaining a target radar image; 22, an image comparing means as a speed distribution obtaining means for obtaining a speed distribution of bright spots; A bright spot selection means as correspondence means for associating a bright spot on a radar image with a target shape in the shape database 23; a posture estimating means 25a for finding a desired attitude; 26a is an angular velocity estimating means for obtaining a target angular velocity, and 27 is an angular acceleration estimating means for obtaining a target angular acceleration. The attitude estimating means 25a and the angular velocity estimating means 26a
The angular acceleration estimating means 27 constitutes a motion estimating means for obtaining a target motion.

FIG. 2 is a diagram for explaining a temporal change of an image according to the first embodiment of the present invention. FIG. 2 is an example of a radar image of a ship, where the horizontal axis u is a range and the vertical axis v is a cross range. Further, it can be seen that the density represents the RCS, and the two-dimensional image of the ship is shown in shades. (A) and (b) are two images observed with a slight time difference, and it can be seen that (b) is slightly rotated with respect to (a). Reference numeral 28 denotes a position vector in the image (a) near the bow.

(C) is a diagram for explaining the velocity vector of the image detected from the difference between the two images (a) and (b), and 29 is the point of the position vector 28 of the image (a). It is a velocity vector.

FIG. 3 is a block diagram showing a detailed configuration of the posture estimating means 25a of FIG. FIG. 4 is a block diagram showing a detailed configuration of the angular velocity estimating means 26a of FIG. FIG. 5 is a block diagram showing a detailed configuration of the angular acceleration estimating means 27 of FIG. In these figures, 30 is a matrix transposing means, 31 is a matrix multiplying means, 32 is an inverse matrix calculating means, 34 is a Λ matrix generating means, 35 is a Q matrix generating means, 3
Reference numeral 6 denotes a matrix addition unit. Note that the matrix multiplication means 31
It is assumed that a matrix input from the left or a matrix input from the bottom is multiplied by a matrix input from the left.

FIGS. 6 and 7 are views for explaining the observation coordinate system according to the first embodiment of the present invention. FIG. 6 is a diagram showing the positional relationship between the transmitting and receiving antennas of the radar and the target. In FIG. X, Y, and Z are coordinate systems based on the target center point 37, Ω1, Ω2, and Ω3 are rotational angular velocities around the X, Y, and Z axes, respectively, and W1, W2, and W3 are X and Y, respectively.
The translation speed along the Y and Z axes. S is an azimuth vector that looks at the transmission / reception antenna 38 from the target center point 37, and corresponds to a target posture based on a line connecting the transmission / reception antenna and the target.

FIG. 7 is a supplementary diagram for explaining the observation coordinate system. In the drawing, reference numeral 39 denotes a virtual screen on which a radar image is projected. P is a position vector of a certain reflection point on the target, and p corresponds to a position vector 28 of this reflection point on the radar image shown in FIG.

Next, the operation will be described. In the apparatus shown in FIG. 1, a transmitter 1, a receiver 2, a transmission / reception switch 3, a transmission / reception antenna 4, and an image reproducing means 5 are the same as those of the conventional apparatus shown in FIG. To play. Since the delay means 21 delays the obtained radar image for a certain period of time, two radar images having a time difference are obtained at the input and output terminals as shown in FIG.

Next, the image comparison means 22 compares the two images to obtain a velocity vector 29 of the reflection point 28.
This method can be realized by, for example, pattern matching based on the shape and reflection intensity around the reflection point. Alternatively, a method such as an optical flow known in an optical image can be used. A set of speed vectors obtained in this manner is a speed distribution.

The bright spot selecting means 24 outputs the obtained ray.
From the image, a bright spot that can correspond to the shape database 23
Select three or more position vectors in the three-dimensional space
Le P _i= (X_i, Y_i, Z_i) And the vector in the radar image
Torr p_i= (U_i, V_i) Is output. Where i is a bright spot
Ordinal number introduced to distinguish between

The posture estimating means 25a calculates a target posture S from the position vector of the selected bright spot and the range coordinates in the radar image. The detailed operation will be described with reference to FIG. However, gamma is a matrix composed of a position vector P of the selected bright spots, u is a matrix composed of range coordinates u _i in the radar images of the selected bright spots.

The matrix transpose means 30 calculates the transpose of the matrix Γ
^Ask for ^T. The matrix multiplying means 31a multiplies Γ ^T by Γ.
The inverse matrix calculation means 32 calculates an inverse matrix ((Γ ^T )) of the matrix (Γ ^T ) Γ
Gamma) seeking ^-1, matrix multiplication unit 31b is (((Γ ^T) Γ)
^-1) multiplied by gamma ^T, further matrix multiplication means 31c multiplies the u, target posture vector S is output as a result.

Next, the angular velocity estimating means 26a calculates a target rotational angular velocity Ω tilde from the position vector of the selected luminescent spot, the cross range coordinates in the radar image, and the target attitude vector S. The detailed operation will be described with reference to FIG. v is a matrix composed of cross-range coordinate v _i in the radar images of the selected bright spots.

The matrix generating means 34 generates a matrix composed of elements of the target posture vector S. The matrix multiplying means 31a multiplies Γ and Λ.

The matrix transpose means 30 finds a transposed matrix (ΓΛ) ^T of the matrix ΓΛ. The matrix multiplying means 31b multiplies (ΓΛ) ^T by ΓΛ. The inverse matrix calculation means 32 calculates the matrix (ΓΛ) ^T
The inverse matrix ((ΓΛ) ^T (ΓΛ)) ^-1 of (ΓΛ) is obtained, and the matrix multiplication means 31c calculates ((ΓΛ) ^T (ΓΛ)) ^-1 and (Γ
Λ) Multiply by ^T , and the matrix multiplying means 31d multiplies by v. As a result, the target rotational angular velocity Ω tilde is output.

Finally, the angular acceleration estimating means 27 calculates the position vector of the selected bright spot, the moving speed of the radar image in the cross range direction, and the target posture vector S
Then, the target rotational angular acceleration Ω tilde dot is calculated from the target rotational angular velocity Ω tilde. The detailed operation will be described with reference to FIG. v dot is a matrix composed of cross-range direction of the moving velocity v _i dots in the radar images of the selected bright spots.

The matrix generating means 34 generates a matrix composed of the elements of the target posture vector S.

The Q matrix generation means 35 generates a matrix Q composed of elements of the target posture vector S and elements of the target rotational angular velocity Ω tilde. The matrix multiplying means 31e calculates Γ and Q
, And the matrix addition means 36 subtracts the matrix ΓQ from vdots.

The matrix multiplying means 31a multiplies Γ by Λ, and the matrix transposing means 30 obtains a transposed matrix (ΓΛ) ^T of the matrix ΓΛ. The matrix multiplying means 31b multiplies (ΓΛ) ^T by ΓΛ. Inverse matrix calculating unit 32 obtains the inverse matrix of ^{((ΓΛ) T (ΓΛ)} ) -1 matrix (ΓΛ) ^T (ΓΛ), matrix multiplication means 3
1c multiplies ((ΓΛ) ^T (ΓΛ)) ^-1 by (ΓΛ) ^T ,
Further, the matrix multiplying means 31d multiplies the matrix (vdot−ΔQ), and as a result, outputs the target rotational angular acceleration Ω tilde dot.

Next, the principle of this operation will be described. First, a velocity vector distribution in a radar image is obtained.
In the coordinate system shown in FIG. 6, X, Y, and Z are coordinate systems based on the target, Ω = (Ω ₁ , Ω ₂ , Ω ₃ ) is the angular velocity of the rotational motion of the target, and W = (W ₁ , W ₂ , W ₃ ) is the velocity representing the translation of the target, and P is the position vector of a point on the target. X
An antenna is located at a distance r ₀ from the origin of the YZ coordinates, and the unit vector on the LOS (Line of Sight) connecting the target origin and the antenna is S.

At this time, the radar image can be handled as an image obtained by projecting the target RCS distribution on a screen having the following vectors u and v as coordinate axes.

[0045]

(Equation 1)

However, since v is the axis of the Doppler frequency, it should be noted that it expands and contracts according to the rotational angular velocity, and its magnitude is not 1. Ω tilde is a vector given by the following equation, and is a rotational angular velocity obtained by combining Ω and W.

[0047]

(Equation 2)

FIG. 7 shows the concept of a radar image screen. In FIG. 7, p = (u, v) is a point target image of the position vector P = (X, Y, Z) projected on the screen. At this time, the coordinates (u,
v) is represented by the following equation.

[0049]

(Equation 3)

The speed of the image on the screen can be obtained by differentiating the equations (4) and (5) with respect to time. First, for the u axis,

[0051]

(Equation 4)

In

[0053]

(Equation 5)

The following equation is obtained using

[0055]

(Equation 6)

The v-axis is also obtained as follows.

[0057]

(Equation 7)

The radar image and its velocity distribution are given by the following four equations: Equation (4), Equation (5), Equation (9), and Equation (10). , And there are at most three independent equations. Then, when simultaneously observing n reflection points (n ≧ 3) whose positions on the target are known, it can be written as follows.

[0059]

(Equation 8)

Here, each matrix is defined as follows.

[0061]

(Equation 9)

However, the subscripts 1, 2, and 3 in the S, Ω tilde, and Ω tilde dots are X, Y, and Z axis elements in the respective vectors. The subscript numbers in the other variables are ordinal numbers for distinguishing the n reflection points.

Here, the target posture S can be obtained by solving the equation (11). The number n of reflection points is n ≧ 3
If so, it can be solved using the well-known least squares method, and the estimated value S of S is given by the following equation.

[0064]

(Equation 10)

That is, the posture estimating means 25a calculates Expression (23) with the configuration of FIG. 3 to obtain an estimated value of the target posture S.

Similarly, the target angular velocity Ω tilde can be obtained by solving equation (12). Number of reflection points n
Can be solved using the well-known least squares method, and the estimated value of Ω tilde Ω tilder bar is given by:

[0067]

[Equation 11]

That is, the angular velocity estimating means 26a
Equation (24) is calculated by the configuration of (2) to obtain an estimated value of the target angular velocity Ω tilde.

Similarly, the target angular acceleration Ω tilde dot can be obtained by solving equation (13). If the number n of the reflection points is n ≧ 3, it can be solved by using the well-known least square method, and the estimated value of the Ω tilde dot is given by the following equation.

[0070]

(Equation 12)

That is, the angular acceleration estimating means 27
Equation (25) is calculated by the configuration of (1) to obtain an estimated value of the target angular velocity Ω tilde dot.

As described above, if there are three or more reflection points whose positions are known or measurable on the target and the radar image and the velocity vector distribution of the bright spots on the image can be observed,
It is understood that the target posture, angular velocity, and angular acceleration can be obtained under the conditions of Expressions (24) and (26).

As described above, according to the configuration of the present embodiment,
The bright spot selecting means 24 obtains the vectors P = (X, Y, Z) and p = (u, v), the image comparing means 22 obtains v dots, and the attitude estimating means 25a obtains the target attitude according to the equation (23). The angular velocity estimating means 26a calculates the target angular velocity according to the equation (24), and the angular acceleration estimating means 27 calculates the equation (2).
Since the target angular acceleration is obtained according to 5), it is possible to obtain a radar device for measuring the movement of the target.

Embodiment 2 FIG. 8 is a block diagram showing another example of the image radar device of the present invention. FIG. 9 is a block diagram showing a detailed configuration of the posture estimating means 25b of FIG. FIG. 10 is a block diagram showing a detailed configuration of the angular velocity estimating means 26b of FIG. In the present embodiment, a determinant evaluation unit 33 is added to the posture estimation unit 25b and the angular velocity estimation unit 26b, and the posture estimation unit 25b and the angular velocity estimation unit 2
6b, a feedback loop is added from the determinant evaluation means 33 to the bright spot selection means 24, respectively. Other configurations are the same as those of the first embodiment.

As in the first embodiment, the posture estimating means 25b calculates the expression (23) to obtain the target posture. However, in order to calculate the expression (23), the matrix ({ ^T )} Must exist. The condition is that the determinant of ({ ^T )} is not zero, and is expressed by the following equation.

[0076]

(Equation 13)

This means that the positional relationship between the selected bright spots is restricted. That is, the posture estimating means 25b calculates the expression (23) by the configuration of FIG. 9 to obtain an estimated value of the target posture S, but calculates the condition of the expression (26), and if the condition is not satisfied, , And instructs the bright spot selecting means 24 to reselect a bright spot through a feedback loop. Therefore, there is an effect that a bright spot satisfying the condition of the equation (26) is always selected, and a target posture can be stably obtained.

That is, the determinant evaluation means 33 calculates the determinant of the matrix ({ ^T )}. If the value is zero, the determinant evaluation means 33 instructs the bright spot selection means 24 to select a bright spot. Tell them to change.

Similarly, the angular velocity estimating means 26b calculates the equation (2)
4) is calculated to obtain the target angular velocity. In order to calculate the equation (24), it is necessary that an inverse matrix of the matrix (ΓΛ) ^T (ΓΛ) exists. The condition is that the determinant of (ΓΛ) ^T (ΓΛ) is not zero, and is expressed by the following equation.

[0080]

[Equation 14]

This means that the combination of the positional relationship and the posture of the selected bright spot is restricted. That is, the angular velocity estimating means 26b calculates Eq. (24) using the configuration of FIG. 10 to obtain an estimated value of the target angular velocity Ω tilde. If the condition of Eq. Instructs the bright spot selecting means 24 to reselect a bright spot via a feedback loop. Therefore, equation (2)
There is an effect that a bright spot satisfying the condition 7) is always selected, and a target angular velocity can be stably obtained.

That is, the determinant evaluation means 33 calculates the determinant of the matrix (ΓΛ) ^T (ΓΛ). Instruct them to change their selection.

Further, similarly, the angular acceleration estimating means 27
Calculates the target angular acceleration by calculating equation (25).
To calculate equation (25), a matrix (ΓΛ) ^T (Γ
The inverse matrix of i) must exist. The condition is given by equation (2)
7) The angular velocity estimating means 26b has already evaluated. Therefore, the angular acceleration estimating means 27 calculates the equation (2)
7) The feedback loop to the evaluation and the bright spot selection means 24 is not required.

As described above, according to the configuration of the present embodiment,
The posture estimating means 25b calculates the condition of the equation (26). If the condition is not satisfied, the posture estimating means 25b instructs the bright spot selecting means 24 to reselect a bright spot via a feedback loop, and the angular velocity estimating means 26b calculates the equation (26). If the condition of (27) is calculated and the condition is not satisfied, the bright-point selecting means 24 is instructed to reselect a bright point via a feedback loop. There is an effect that the desired exercise can be stably obtained when selected.

Embodiment 3 FIG. 11 is a block diagram showing another example of the image radar device of the present invention. In FIG. 11, reference numeral 40 denotes target distance measuring means (distance measuring means), 41 denotes coordinate conversion means, 42 denotes angular velocity correcting means, and 43 denotes angular acceleration correcting means. Other configurations are the same as those of the first embodiment.

Next, the operation will be described. Embodiment 1
As described above, the target posture S from the posture estimating means 25a, the target angular velocity Ω tilde from the angular velocity estimating means 26a, and the target angular acceleration Ω from the angular acceleration estimating means 27.
A tilde dot is obtained respectively.

However, as defined in equation (3), the Ω tilde is a combination of the target rotational angular speed Ω and the translation speed W, and
It is an angular velocity based on S. Therefore, in order to obtain the target rotational angular velocity Ω, the following equation derived from equation (3) may be calculated.

[0088]

(Equation 15)

Then, the target tracking means 7 measures the translation speed W of the target, the target distance measuring means 40 measures the distance r ₀ to the target, and the angular velocity correcting means 42 calculates the target angular velocity Ω by the equation (28). calculate.

However, the translation speed of the target which can be measured by the target tracking means 7 is the coordinate system {η} unique to the radar shown in FIG.
Is a value W ′. On the other hand, since the translation speed W of the target required in Expression (28) is defined by the coordinate system XYZ unique to the target, the coordinate system needs to be converted. In general, conversion by rotation of two orthogonal coordinate systems having the same origin is given by the following equation, and three independent variables are θ, φ, and ψ.

[0091]

(Equation 16)

Here, θ, φ, and ψ are angles generally called Euler angles, and the relationship is shown in FIG. Also,
Since the target tracking means 7 can measure the azimuth of the target as viewed from the antenna, it can know the element of the vector S in FIG. 6 in the {η} coordinate system. Therefore, the coordinate conversion means 41
The element of S output by the target tracking means 7 is substituted for {η} on the right side of the equation (29), and the attitude estimating means 25a is substituted for XYZ on the left side.
By substituting the element of S output by the above equation, three variables θ, φ, and ψ are obtained by solving a cubic simultaneous equation. continue,
The coordinate conversion unit 41 substitutes the element of the target translation speed W ′ output by the target tracking unit 7 into {η} on the right side of Expression (29), and obtains the translation speed W on the left side. Then, the angular velocity correcting means 42 can calculate the target angular velocity Ω by equation (28).

Similarly, a target rotational angular acceleration Ω dot can be obtained. Equation (28) is differentiated with respect to time to obtain the following equation.

[0094]

[Equation 17]

Then, the target tracking means 7 measures the translation speed W 'of the target, the coordinate conversion means 41 converts it into the translation speed W, and the target distance measurement means 40 measures the distance r ₀ to the target.
The delay means 21b and the matrix addition means 36a determine the time differential S dot of the target posture S, the delay means 21c and the matrix addition means 36b determine the time differential W dot of the target translation speed W, and the angular acceleration correction means 43 calculates The target angular acceleration Ω dot is calculated by (30).

As described above, according to the configuration of the present embodiment,
The target rotational angular velocity Ω and the target rotational angular acceleration Ω dot can be obtained, and in addition to the effect of the first embodiment, the target motion not including the translational motion component and the translational motion can be separated. A radar device having the desired effect can be obtained.

Embodiment 4 FIG. 13 is a block diagram showing the configuration of the bright spot selecting means 24 and the shape database 23 showing another example of the image radar apparatus of the present invention. In FIG. 13, reference numeral 44 denotes an RCS added to the shape database 23.
The database 45 is an RCS comparing means. FIG. 14 is a schematic diagram of a target observed by the image radar device according to this embodiment. In FIG. 14, 46a, 46b, 4
6c are three reflection points (radio wave scatterers) on the target,
The CS differs according to the size of the illustrated sphere.

The coordinates of these reflection points and their RCS are stored in the shape database 23 and the RCS database 44, respectively. For this purpose, the coordinates and RCS of some parts of the target may be measured in advance and stored in the shape database 23, or a radar reflector having a RCS conveniently designed may be installed on the target and the coordinates thereof determined. May be recorded and stored in the shape database 23.

Next, the operation will be described. In the apparatus shown in FIG. 13, the RCS comparing unit 45 compares the luminance of each reflection point of the input radar image, that is, RCS, with the RCS recorded in the RCS database 44, and, if the luminance coincides with the RCS, the RCS The coordinates (u,
v) and the coordinates (X, Y, Z) of the reflection point on the target are output.

That is, the bright spot selecting means 24 selects a bright spot using the recorded RCS as a clue, and further associates the bright spot on the radar image with the reflection point on the target to obtain a vector P = (X, Y, Z) and p = (u, v).

As described above, according to the configuration of the present embodiment,
Since the bright spot selecting means 24 selects the bright spot using the recorded RCS as a clue, in addition to the effect of the invention of the first embodiment, the bright spot selection becomes more reliable and the movement of the target can be improved. It is possible to obtain a radar device having an effect required for stability.

Embodiment 5 FIG. FIG. 15 is a block diagram showing the configuration of the bright spot selection means 24 and the shape database 23 showing another example of the image radar apparatus of the present invention. In FIG. 15, reference numeral 47 denotes a reflection point number database added to the shape database 23, and reference numeral 48 denotes a reflection point number comparison unit. FIG. 16 is a schematic diagram of a target observed by the image radar apparatus according to this embodiment. In FIG. 16, 49a, 49
b, 49c, 49d, 49e, and 49f are a plurality of dense reflection points on the target.

In the apparatus shown in FIG. 13 of the fourth embodiment, the bright point selecting means 24 selects a bright point using the recorded RCS as a clue, but in the apparatus shown in FIG. Bright spots are selected based on the number of densely reflecting points.

Therefore, it is assumed that the coordinates and the number of these reflection points are stored in the shape database 23 and the reflection point number database 47, respectively. For this purpose, the coordinates and the number of reflection points for three or more target portions may be measured and stored in the shape database 23 in advance, or a plurality of radar reflectors may be installed for each of the three or more target portions. Alternatively, the coordinates and the number may be recorded and stored in the shape database 23.

Next, the operation will be described. In the apparatus shown in FIG. 15, the number-of-reflection-points comparison means 47 compares the number of reflection points appearing densely on the input radar image with the number of reflection points recorded in the reflection-point number database 47, and, for those which agree with each other, The coordinates (u,
v) and the coordinates (X, Y, Z) of the reflection point on the target are output.

That is, the bright spot selecting means 24 selects a bright spot using the recorded number of reflection points as a clue, and further associates the bright spot on the radar image with the reflection point on the target to obtain a vector P = (X , Y, Z) and p = (u, v).

As described above, according to the configuration of the present embodiment,
Since the bright spot selecting means 24 selects the bright spot based on the recorded number of reflection points, in addition to the effect of the invention of the first embodiment, the selection of the bright spot becomes more reliable and the movement of the target can be performed. It is possible to obtain a radar device having an effect required more stably.

Note that not only the number of reflection points but also the distribution pattern can be used as a clue to select a bright point.

[0109]

According to the present invention, there is provided an image radar apparatus for observing a target and obtaining the radar image.
Image continuous acquisition means for continuously obtaining a target radar image,
A speed distribution acquisition unit that compares two consecutive radar images and obtains a speed distribution of the bright spots based on a change in the position of the bright spots on the radar image; and a shape database in which a plurality of target shapes are stored in advance. And a motion estimating means for obtaining a target motion from the radar image, the velocity distribution, and the target shape. Therefore, it is possible to obtain an image radar device that measures a target motion.

Further, a feedback loop from the motion estimating means to the corresponding means is further provided, and when the output of the motion estimating means does not satisfy a predetermined condition, the corresponding means re-associates with the target shape. Therefore, there is an effect that a bright point satisfying a predetermined condition is always selected, and a desired movement can be stably obtained.

Further, the motion estimating means has an attitude estimating means for obtaining a target attitude based on the positional relationship of the bright spots on the radar image in the range direction. Therefore, it is possible to obtain an image radar device that obtains a target posture.

The motion estimating means has an angular velocity estimating means for obtaining a target rotational angular velocity based on the positional relationship of the bright spot on the radar image in the cross range direction. Therefore, it is possible to obtain an image radar device that obtains a target rotational angular velocity.

Tracking means for obtaining the target moving speed; distance measuring means for measuring the distance to the target; and angular velocity correcting means for correcting the rotational angular velocity of the target based on the moving speed of the target and the distance to the target. Is further provided. Therefore, it is possible to obtain an image radar device that accurately obtains the target rotational angular velocity.

Further, the motion estimating means has an angular acceleration estimating means for obtaining a target rotational angular acceleration based on a changing speed of a luminescent spot on the radar image in a cross range direction. Therefore, it is possible to obtain an image radar device that obtains a target rotational angular acceleration.

Further, tracking means for obtaining the moving speed of the target, distance measuring means for measuring the distance to the target, and angular acceleration correcting means for correcting the rotational angular acceleration of the target based on the moving speed and the distance to the target. Is further provided. Therefore, it is possible to obtain an image radar device that accurately obtains a target rotational angular acceleration.

The shape database stores at least three radio wave scatterers having different radio wave scattering cross-sectional areas of each target as a target shape, and the corresponding means stores at least three bright spots on the radar image in the shape database. Correlate with the target shape. For this reason, it is possible to obtain a radar device having an effect that the association is more reliably performed and the target motion is more stably obtained.

Further, the shape database stores a plurality of dense radio wave scatterers of each target as a target shape, and the corresponding means stores a plurality of dense luminescent spots on the radar image with the target shape of the shape database. Correspond. For this reason, it is possible to obtain a radar device having an effect that the association is more reliably performed and the target motion is more stably obtained.

Further, the shape database stores the radio wave scatterers distributed in different numbers in at least three places of each target as the target shape, and the corresponding means uses the different numbers in at least three places on the radar image. The distributed bright spots are associated with target shapes in the shape database.
Therefore, the association is further ensured, and it is possible to obtain a radar apparatus having an effect of more stably obtaining a target motion.

Furthermore, the shape database stores the distribution pattern of the radio wave scatterers of each target as the target shape, and the correspondence unit associates the distribution pattern of the bright spots on the radar image with the target shape in the shape database. Therefore, the association is further ensured, and it is possible to obtain a radar apparatus having an effect of more stably obtaining a target motion.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an image radar apparatus according to the present invention.

FIG. 2 is a diagram illustrating a temporal change of an image according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a detailed configuration of a posture estimating unit in FIG. 1;

FIG. 4 is a block diagram illustrating a detailed configuration of an angular velocity estimating unit in FIG. 1;

FIG. 5 is a block diagram showing a detailed configuration of an angular acceleration estimating unit of FIG. 1;

FIG. 6 is a diagram illustrating a positional relationship between a transmitting / receiving antenna of a radar and a target for explaining an observation coordinate system according to the first embodiment of the present invention.

FIG. 7 is an auxiliary diagram illustrating an observation coordinate system according to the first embodiment of the present invention.

FIG. 8 is a block diagram showing another example of the image radar device of the present invention.

FIG. 9 is a block diagram illustrating a detailed configuration of a posture estimating unit in FIG. 8;

FIG. 10 is a block diagram illustrating a detailed configuration of an angular velocity estimating unit in FIG. 8;

FIG. 11 is a block diagram showing another example of the image radar device of the present invention.

FIG. 12 is a diagram showing a relationship among Euler angles θ, φ, and 用 い used for conversion by rotation of two orthogonal coordinate systems having the same origin.

FIG. 13 is a block diagram showing a configuration of a bright spot selection unit and a shape database showing another example of the image radar apparatus of the present invention.

FIG. 14 is a schematic diagram of a target observed by the image radar device.

FIG. 15 is a block diagram showing a configuration of a bright spot selection unit and a shape database showing another example of the image radar apparatus of the present invention.

FIG. 16 is a schematic diagram of a target observed by the image radar device.

FIG. 17 is a block diagram of a conventional radar device.

FIG. 18 is a diagram for explaining the geometry of observation by a conventional radar device.

FIG. 19 is a diagram for explaining the geometry of observation by a conventional radar device.

FIG. 20 is a block diagram illustrating a detailed configuration of an image reproducing unit.

[Explanation of symbols]

7 Target tracking means (tracking means), 21 delay means (continuous image obtaining means), 22 image comparing means (speed distribution obtaining means), 23 shape database, 24 bright spot selecting means (corresponding means), 25, 25a, 25b Posture Estimation means (motion estimation means), 26, 26a, 26b angular velocity estimation means (motion estimation means), 27 angular acceleration estimation means (motion estimation means), 40 target distance measurement means (distance measurement means), 42
Angular velocity correction means, 43 angular acceleration correction means;

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Seiji Suganuma 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 5J070 AC01 AC02 AC06 AC07 AC11 AC13 AC20 AE02 AH50 AJ02 AJ13 AK04 AK40 BA10 BB02 BB03 BB04 BB05 BB20 BE01 BE03 BG06

Claims (11)

[Claims] 1. A radar apparatus for observing a target and obtaining a radar image of the target, comprising: a continuous image obtaining unit for continuously obtaining the target radar image; A speed distribution obtaining means for obtaining a speed distribution of the bright spot based on a change in position of the bright spot on the image; a shape database in which a plurality of target shapes are stored in advance; An image radar apparatus comprising: a correspondence unit that associates with a target shape; and a motion estimation unit that obtains a target motion from the radar image, the velocity distribution, and the target shape. 2. The apparatus according to claim 1, further comprising a feedback loop from the motion estimating unit to the corresponding unit, wherein the corresponding unit re-associates with a target shape when an output of the motion estimating unit does not satisfy a predetermined condition. The image radar device according to claim 1, wherein: 3. The apparatus according to claim 1, wherein the motion estimating means includes attitude estimating means for obtaining a target attitude based on a positional relationship of a luminescent spot on the radar image in a range direction.
Or the image radar device according to 2. 4. An apparatus according to claim 1, wherein said motion estimating means has an angular velocity estimating means for obtaining a target rotational angular velocity based on a positional relationship of a luminescent spot on the radar image in a cross range direction. The image radar device according to any one of the above. 5. A tracking means for obtaining a moving speed of a target, a distance measuring means for measuring a distance to the target, and an angular velocity for correcting the rotational angular speed of the target based on the moving speed of the target and the distance to the target. The image radar apparatus according to claim 4, further comprising a correction unit. 6. The motion estimation unit according to claim 1, wherein the motion estimation unit includes an angular acceleration estimation unit that obtains a target rotational angular acceleration based on a change speed of a luminescent spot on the radar image in a cross range direction. 6. The image radar device according to any one of 5. 7. A tracking means for obtaining a target moving speed, a distance measuring means for measuring a distance to the target, and an angular acceleration for correcting the rotational angular acceleration of the target based on the moving speed and the distance to the target. 7. The image radar apparatus according to claim 6, further comprising a correction unit. 8. The shape database stores at least three radio wave scatterers having different radio wave scattering cross-sectional areas of each target as the shape of the target, and the correspondence unit stores at least three bright spots on the radar image. 8. The image radar apparatus according to claim 1, wherein the image radar is associated with the target shape in the shape database. 9. The shape database stores a plurality of dense radio wave scatterers of each target as the shape of the target, and the correspondence unit stores a plurality of dense luminescent spots on the radar image in the shape database. 8. The image radar device according to claim 1, wherein the image radar device is associated with the target shape. 10. The shape database stores radio wave scatterers distributed in different numbers in at least three places of each target as the shape of the target, and the correspondence unit stores the radio wave scatterers in at least three places on the radar image. 8. The image radar apparatus according to claim 1, wherein bright spots distributed in different numbers are associated with the target shapes in the shape database. 11. The shape database stores a distribution pattern of radio wave scatterers of each target as the shape of the target, and the correspondence unit stores a distribution pattern of bright spots on the radar image in the shape database. 8. The image radar device according to claim 1, wherein the image radar device is associated with a target shape.