JP2000321353A - Radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar device capable of automatically identifying an observation target such as a ship rocked by waves in real time. SOLUTION: In this radar device for observing a floating target such as a ship, a target rock estimation means 16 estimates movement of the rocking observation target on the basis of a database on target tracking means outputs, state information about waves and structure parameters of various targets, so that kinds of assumed movement are reduced to create a reference image compared and collated with a radar image. Accordingly, the rocking floating target can be automatically identified in real time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar apparatus for obtaining a radar image of an observation target and automatically recognizing and identifying the target, and more particularly to an automatic identification of an observation target such as a ship swaying by waves.

[0002]

2. Description of the Related Art Conventionally, as this type of radar apparatus, there is one disclosed in Japanese Patent Publication No. 2738244. FIG.
FIG. 4 is a diagram described in the above document. In FIG.
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 unit, 6 is a correlation operation unit, 7 is a target tracking unit, 8 is a point image response estimation unit, and 9 is a target. Aspect angle estimating means, 10 is RCS (Radar Cross Section is abbreviated to RCS as appropriate) calculating means, 11 is target shape database, 12 is convolution integrator, 13 is maximum value detecting means, and 14 is target identification result. Output means. FIGS. 15 and 16 are diagrams for explaining the observation geometry in this conventional apparatus.
4 is a transmitting / receiving antenna and 35 is an observation target. FIG. 17 is a diagram showing a detailed configuration of the image reproducing means 5 in FIG. 14. 36 is a range compressing means, 37 is a motion compensating means, 38 is a cross range compressing means, and 39 is a two-dimensional storage means.

Next, the operation of this conventional device will be described with reference to FIG.
This will be described with reference to FIGS. The high-frequency signal generated by the transmitter 1 is radiated from the transmission / reception antenna 4 to the observation target 35 via the transmission / reception switch 3. A part of the high-frequency signal applied to the observation target is reflected by the observation target, received again by the transmission / reception antenna 4, amplified and detected by the receiver 2 via the transmission / reception switch 3, and then reproduced by the image reproducing means 5. It is converted to a radar image representing the above RCS distribution.

[0004] The operation of the image reproducing means 5 will be described below. As shown in FIG. 17, the received signal output from the receiver 2 is input to the image reproducing unit 5, and the range compression unit 36 first performs a process of improving the range resolution, that is, a pulse compression. The received signal after range compression is stored in the two-dimensional storage means 39 by the range bin number m and the pulse hit number n.
Is stored according to. In order to remove random components harmful to image reproduction from the movement of the observation target 35, the received signal is 2
Phase compensation and range bin rearrangement are performed by the motion compensator 35 so that the Doppler frequency of the center point 20 of the observation target 35 is read out from the dimension storage means 39 and stored in the two-dimensional storage means 39 again. You.

Now, as shown in FIG.
Assuming that is rotated by a swiveling motion, different points on the target that are in the same range bin will produce reflected waves of different Doppler frequencies. Similarly, even when the observation target 35 is moving straight, different points on the target existing in the same range bin generate reflected waves having different Doppler frequencies. This is because the motion of the observation target shown in FIG.
It can be understood from the fact that the operation becomes equivalent to the movement of the observation target shown in FIG.

Utilizing this, the cross range compression means 38
Performs the FFT (Fast Fourier Transform of Fast Fourier Transform as appropriate, abbreviated as FFT) on the range-combined signal for each range bin, thereby improving the resolution of the cross range in the direction orthogonal to the range. By these processes, the received signal is increased in resolution in both the range and cross range directions, and the RC of each point on the observation target is
It is converted to a radar image representing the S distribution.

[0007] On the other hand, the target tracking means 7 measures the distance and direction of the observation target from the received signal and their temporal changes, and obtains the movement characteristics of the observation target 35, such as the moving direction, position, speed, and acceleration. A point image response function corresponding to the impulse response of the radar device is calculated by the point image response estimating means 8 from the result and the specifications of the radar device. Also,
The target aspect angle estimating means 9 estimates the target aspect angle from the moving direction and the position of the observation target 35 calculated by the target tracking means 7. The RCS calculating means 10 sequentially reads out the target three-dimensional shape data stored in the target shape database 11, and calculates the RCS distribution on the observation target based on the estimated target aspect angle and radar specifications. RCS
To calculate the distribution, for example, GTD (Geometrical Theory
f Diffraction) and PTD (Physical Theory of Diffra)
ction) can be used.

In order to identify the type of the target, it is necessary to compare and collate the radar image obtained by the image reproducing means 5 with the RCS distribution. However, since the range resolution of the radar image is determined depending on the transmission bandwidth and the cross-range resolution is determined depending on the movement of the target, the resolution of the RCS distribution, that is, the resolution of the target shape data does not generally match, Cannot compare / collate. Therefore, in order to match this, the convolution integrator 12 performs convolution integration of a point spread response function on the RCS distribution to generate a reference image for comparison / collation.

The correlation calculating means 6 calculates a correlation value between the radar image and the sequentially generated reference image, and the maximum value detecting means 13 specifies a maximum reference image from the sequentially calculated correlation values. The target identification result output means 14 reads target information corresponding to the specified reference image, for example, a shape and a name from the target shape database 11 and outputs it, thereby obtaining a radar image of the observation target and obtaining the target image. A radar device for automatically recognizing and identifying the object can be realized.

[0010]

The conventional apparatus is configured as described above. In order to observe and identify a water target such as a ship, any set of roll, pitch and yaw movements by waves is required. Assuming matching, it is necessary to generate a reference image to be compared and matched with the radar image, and there is a problem that automatic recognition and identification of a target cannot be performed in real time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a radar apparatus which can observe a moving water target such as a ship and can automatically recognize and identify the target in real time. With the goal. It is another object of the present invention to obtain a radar device that improves the performance of identifying a moving water target.

[0012]

According to a first aspect of the present invention, there is provided a radar apparatus for observing a water target such as a ship. Image reproducing means for reproducing the radar image of the above, measuring the distance and azimuth of the observation target and their time change from the received signal, the position of the observation target,
Target tracking means for obtaining movement characteristics such as moving direction and speed; target aspect angle estimating means for estimating an angle between a line of sight and the moving direction of the observation target based on the output of the target tracking means; and the target tracking means Target sway estimating means for estimating the sway of the observation target based on the output, the state information of the wave on the water surface, and a database in which the structural parameters of various targets on the water are stored in advance; A point image response estimating means for estimating a point image response function of the radar image based on the output; and a database storing the target aspect angle and target shape data to be recognized / identified in advance. Means for calculating a radar cross section distribution of the radar image, and a convolution product of the radar cross section distribution on the observation target and the point image response function of the radar image. Means for generating a reference image to be compared and collated with the radar image of the image reproduction means outputting performed,
Correlation calculation means for obtaining a correlation between the radar image of the observation target and the reference image, maximum value detection means for specifying a reference image having the maximum correlation, information on a target corresponding to the specified reference image And a target identification result output means for reading out and outputting from the target shape database.

The radar apparatus according to a second aspect of the present invention is the radar apparatus according to the first aspect, further comprising a water surface measuring means for measuring and outputting a period and a direction of a wave on the water surface from a reception signal of the radar device. Features.

According to a third aspect of the present invention, in the radar apparatus according to the first aspect, the image reproducing parameter of the image reproducing means for reproducing the radar image of the observation target is adjusted based on the estimation result of the fluctuation of the observation target. It is characterized by being performed.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the transmission parameters of the transmitter of the radar apparatus are adjusted based on the estimation result of the fluctuation of the observation target. I do.

According to a fifth aspect of the present invention, in the radar apparatus according to the first aspect, the estimation result of the fluctuation of the observation target is obtained by:
Priority control means for controlling output to the point image response estimating means in order from the motion corresponding to the Doppler frequency having a high appearance frequency is provided.

According to a sixth aspect of the present invention, in the radar apparatus according to the first aspect, the target aspect angle is estimated based on information from the target tracking means and weather information on the ocean current or the wind. Features.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration block diagram showing a first embodiment of the radar apparatus of the present invention. In FIG. 1, 1 to 7, 9 to 14 are the same or equivalent means as those of the conventional apparatus shown in FIG. 1
Reference numeral 5 denotes a database in which structural parameters of various targets on the water are stored in advance, and reference numeral 16 denotes an observation target based on an output of the target tracking means 7, wave state information on the water surface, and a database in which structural parameters of various targets on the water are stored in advance. Is a target fluctuation estimating means for estimating a period and an angular amplitude of the movement of the pitch and roll. 8a estimates the point image response function of the radar image based on the output of the target tracking means 7 and the output of the target fluctuation estimating means 16.

FIG. 2 is a diagram for explaining the fluctuation of the observation target on the water and the observation geometry of the waves in the first embodiment. In FIG. 2, 17 is an observation target on water, 18
Is a line of sight (hereinafter referred to as a line of sight) connecting the transmitting / receiving antenna 4 of the radar and the observation target 17.
Is abbreviated as LOS), 19 is the movement direction of the observation target 17 and the aspect angle formed by the LOS, 20 is the movement of the target roll, 21 is the movement of the target pitch, 22
Is the yaw motion of the target, 23 is the angle between the direction of the wave on the water surface and the moving direction of the observation target, 24 is the period of the wave, and 25 is the height of the wave.

Next, the operation will be described with reference to FIGS. In FIG. 1, the operations of means 1 to 7 and 9 to 14 are the same as those of the conventional apparatus shown in FIG. The radar image of the observation target is reproduced from the reception signal of the receiver output,
On the other hand, a reference image to be compared and collated with the radar image of this observation target is generated, a mutual correlation is obtained, a reference image having the maximum correlation is specified, and information on a target corresponding to the specified reference image is identified. As a result, it is read from the target shape database and output. In generating a reference image to be compared and collated with the radar image, a target tracking means output,
Operation of the newly configured target fluctuation estimating means 16 for estimating and outputting the roll and pitch movements of the observation target based on the state information of the wave on the water surface and the database in which the structural parameters of various targets on the water are stored in advance. Will be described in detail below.

The operation of the target fluctuation estimating means 16 will be described in detail. Here, it is assumed that the target is observed from the front or the rear, that is, the case where the aspect angle 19 is near 0 or π in FIG. this is,
There are two reasons. First, the radar image consists of a range or distance on one axis and a cross-range on the other, but the cross-range is an unstable axis that changes with the movement of the target, so it is elongated like a ship. When observing the target of the shape, it is desirable to observe such that the stable range axis is in the longitudinal direction. Second, in the radar apparatus of the present invention, the motion of a ship is predicted from its structure and the state of the waves. However, it is difficult to predict the yaw motion as compared with the roll and pitch because the yaw motion mainly depends on steering. Therefore, the direction in which the target is observed from the front or the rear, where the influence of the yaw motion is unlikely to appear in the radar image, is selected.

First, the pitch movement will be described. It is known that the movement of the pitch of the water target is mainly determined by the wave condition. The pitch period T _P when the ship motion is synchronized with the wave is given by the following equation. This formula can be found in, for example, Kansai Shipbuilding Association, “Shipbuilding Design Handbook (4th edition)”, Kaibundo Shuppan
This is a modification of the equation described in pp. 413 (1983).

[0023]

(Equation 1)

Here, V is the moving speed of the target, θ is the angle 23 between the direction of the wave on the water surface and the moving direction of the target, and g is the gravitational acceleration. _TW is the time period of the wave and is given by the following equation.

[0025]

(Equation 2)

Here, _LW is the wave period 24. It is also known that the shape of the water surface can be approximated by a sine wave when the wave height H _W (25 in FIG. 2) is smaller than the wave period L _W (24 in FIG. 2). . Therefore, the total length of the target is the cycle L _W
If the pitch angle is sufficiently short as compared with, the pitch angle amplitude _AP is approximately given by the following equation, considering that the pitch angle matches the inclination of the water surface.

[0027]

(Equation 3)

From the above, the wave period L _W and the wave height
And H _W, if angle between the directions and the moving direction of the target wave θ is known, it is possible to estimate the period and angle amplitude of the pitch movement of the observation target.

Next, the movement of the roll will be described. It is known that the roll motion of a water target depends on the structure of the hull. The roll period _Tr is given by the following equation.
This formula is, for example, pp.4 of the above shipbuilding design handbook (4th edition)
14.

[0030]

(Equation 4)

Here, GM is a hull structural parameter representing the distance between the center of gravity of the hull and the center of moment. K _XX is the apparent radius of gyration around the vertical axis passing through the center of gravity, and is given by the following equation.

[0032]

(Equation 5)

Here, B is the full width of the hull. In addition, c is a coefficient determined by the type of ship and the loading state, and a typical value is described in pp. 414 of the aforementioned Shipbuilding Design Handbook (4th edition).

[0034] The angle amplitude A _r of the roll is approximately given by the following equation. This equation is described in, for example, pp. 417 of the aforementioned Shipbuilding Design Handbook (4th edition), and can be solved using an iterative method or the like.

[0035]

(Equation 6)

However, N is an extinction coefficient, and its typical value depends on the type of ship, and is described in pp. 415 of the aforementioned Shipbuilding Design Handbook (4th edition).
It is described in. Θ is the maximum wave inclination angle and is given by the following equation.

[0037]

(Equation 7)

Γ is the effective slope coefficient of the wave, which is approximated by the following equation.

[0039]

(Equation 8)

Where OG is the height of the center of gravity with respect to the water surface,
d is the draft.

From the above, the wave period L _W and the wave height H
_W , the angle θ between the direction of the wave and the target moving direction, the distance GM between the center of gravity of the hull and the moment center, the total width B of the hull, the coefficient c determined by the type and loading state of the ship, the extinction coefficient N, and the water surface as a reference. If the height of the center of gravity OG and the draft d are known, the period and the angular amplitude of the roll motion of the observation target can be estimated.

Various structural parameters necessary for estimating the pitch, roll period, and angular amplitude of the observation target are stored in the database 15 in advance, and are provided to the target motion estimation means 16. In the first embodiment, the direction, cycle, and height of the wave information of the water surface wave are externally provided to the target sway estimating means 16 as weather information.

As described above, the period and angle amplitude of the roll and pitch of the observation target can be estimated, and the point image response function corresponding to the impulse response of the radar apparatus is estimated from the result and the specifications of the radar apparatus. It is calculated by the means 8a. Then, the convolution integrator 12 performs convolution integration of the point spread response function on the RCS distribution on the observation target, and generates a reference image for comparison / collation.

The correlation calculating means 6 calculates the correlation between the radar image and the sequentially generated reference image, the maximum value detecting means 17 specifies the reference image having the maximum correlation, and the target identification result output means 14 determines the correlation. The target information corresponding to the specified reference image, for example, the shape and the name are read out from the target shape database 11 and output.

In the above, an example has been described in which the wave state information on the water surface is obtained from external weather information to estimate the motion (sway) of the observation target. Since it is known that there is a relationship, it is also possible to estimate the motion (sway) of the observation target by obtaining information on the wind above the water from external weather information.

As described above, according to the first embodiment of the present invention, the period and angular amplitude of the roll and pitch movements of the observation target on the water can be estimated by the target fluctuation estimating means. It is no longer necessary to assume any combination of exercises, rolls, and pitches, greatly reducing the types of exercises that can be assumed, and generating reference images that can be compared and matched with radar images. Automatic recognition and identification of targets can be performed in real time.

Embodiment 2 FIG. 3 is a block diagram showing a second embodiment of the radar apparatus according to the present invention. In FIG. 3, reference numerals 1 to 7, 8a, and 9 to 16 are the same or equivalent means as those of the first embodiment shown in FIG. 26 is a water level measuring means.

FIG. 4 is a view for explaining the observation geometry of the water level measuring means 26 according to the second embodiment of the present invention. In FIG. 4, reference numeral 27 denotes a platform on which a radar device is mounted, and reference numerals 28a, 28b, and 28c denote three footprints of antennas for observing the water surface.

Next, the operation will be described. In FIG. 3, the operation of each means except the water level measuring means 26 is as follows.
This is the same as or equivalent to that described in Embodiment 1 with reference to FIG. The water level measuring means 26 measures the state of the water level in the observation water area using the received signal of the radar device.

The operation of the water level measuring means 26 will be described below with reference to FIGS. 4, the water measuring means 26, based on the direction of the wave, and the region 28a of the angle theta _1, directed to the antenna to angle theta ₂ of the region 28b, obtains the distance distribution of each of the reflected power. Since the reflection coefficient of the water surface depends on the difference between the water surface and the incident angle of the radio wave, the period of the wave on the water surface in the radio wave incident direction can be known from the distance distribution of the reflected power. FIG. 5 is a diagram for explaining the principle of measuring the wave period in FIG. FIG.
5A shows the distance distribution of the reflected power in the region 28a shown in FIG. 4, and FIG. 5B shows the distance distribution of the reflected power in the region 28b shown in FIG. Now, assuming that the period of the wave is L _W , the measured value of the period of the wave in the region 28a is L _W1 , and the measured value of the period of the wave in the region 28b is L _W2 , the following relationship is established.

[0051]

(Equation 9)

Here, the following equation is obtained by introducing the difference Δθ between the angles θ ₁ and θ ₂ .

[0053]

(Equation 10)

[0054] Since the unknown variable in the equation (11) is only the period L _W of the wave can be obtained this from the equation (11). Further, the result is expressed by equation (9) or equation (1).
By substituting into 0), the direction of the wave can be obtained.

Next, referring to FIG.
Measures the distance (height) to the water surface by directing the antenna to the area 28c immediately below. By changing the measurement position or time several times, it is possible to obtain a change in the distance to the water surface as shown in FIG. From this graph, the wave height H _W can be obtained.

As described above, according to the second embodiment of the present invention, in addition to the effects of the first embodiment, a real-time signal from the water surface measuring means for measuring the state of the water surface in the observation water area from the received signal of the radar device is provided. By using the wave information, the identification performance of the observation target on the oscillating water can be improved.

Embodiment 3 FIG. 7 is a configuration block diagram showing a third embodiment of the radar apparatus of the present invention. 7, reference numerals 1 to 4, 6, 7, 8a, and 9 to 16 are the same or equivalent means as those in the first embodiment shown in FIG.
5a will be described below.

Next, the operation will be described. In FIG. 7, the operation of all means except the image reproducing means 5 is the same as that of the first embodiment shown in FIG. In the third embodiment, when reproducing the radar image of the observation target from the reception signal output from the receiver, the image reproduction unit 5a uses the image reproduction parameter based on the estimation result of the fluctuation of the observation target by the target fluctuation estimation unit 16. It is characterized by being adjusted.

For example, the data length used for image reproduction is determined as follows. In radar images, the cross range of the observation target is represented by the Doppler frequency, so its resolution is determined by the length of the data used for image reconstruction (observation time). In general, the longer the data length, the higher the cross range resolution improves. On the other hand, when the movement of the target is periodic such as a roll or a pitch, the Doppler frequency of the target changes with time, so that if the length of data is increased, a phenomenon that an image is blurred in the cross range occurs. Therefore, by adjusting the data length in proportion to the period of the roll or the pitch, the blur of the image on the cross range axis can be made constant.

The data length used for image reproduction may be determined as follows. Now, assuming that the observation target is performing a pendulum motion having a period T and an angular amplitude A, the Doppler frequency at a point separated by a distance r from the center of rotation is represented by the following equation (1).
Given in 2).

[0061]

[Equation 11]

Here, λ is the transmission wavelength. Therefore, the resolution Δr of the cross range is given by the following equation.

[0063]

(Equation 12)

Since the resolution of the Doppler frequency is given by the reciprocal of the data length, in order to keep the cross range resolution constant, the data length may be determined so as to be proportional to T / A.

As described above, according to the third embodiment of the present invention, in addition to the effect of the first embodiment, the image reproduction for reproducing the radar image of the observation target based on the estimation result of the fluctuation of the observation target By adjusting the image reproduction parameters of the means, the blur of the image on the cross-range axis can be made constant, and when the observation target is performing a pendulum motion with a period T and an angular amplitude A, the cross-range resolution Can be made constant, and the discrimination performance of a moving water target can be improved.

Embodiment 4 FIG. 8 is a configuration block diagram showing a fourth embodiment of the radar apparatus of the present invention. In FIG. 8, reference numerals 2 to 7, 8a, and 9 to 16 are the same as or equivalent to those of the apparatus of the first embodiment shown in FIG. 1a
Will be described below.

Next, the operation will be described. 8, the operation of all means except the transmitter 1 is the same as that of the first embodiment shown in FIG. In the third embodiment, the transmitter 1a of the radar device generates a high-frequency pulse signal.
The feature is that adjustment is made based on the estimation result of the fluctuation of the observation target of No. 6.

For example, the pulse repetition frequency of the transmitter 1a is determined as follows. As described in the third embodiment, in the radar image, the target cross range is represented by the Doppler frequency. Therefore, if the pulse repetition frequency is higher than the maximum value of the target Doppler frequency, image aliasing occurs. The target identification performance is degraded. Therefore, the pulse repetition frequency must be chosen to be greater than the target Doppler frequency maximum. Now, assuming that the observation target is performing a pendulum motion having a period T and an angular amplitude A, the Doppler frequency at a point separated by a distance r from the rotation center is given by Expression (12). May be determined in proportion to.

As described above, according to the fourth embodiment of the present invention, in addition to the effect of the first embodiment, the transmission parameter of the transmitter of the radar device is set based on the estimation result of the fluctuation of the observation target. By performing the adjustment, it is possible to obtain a radar image having no aliasing of the image, and it is possible to improve the identification performance of a moving water target.

Embodiment 5 FIG. FIG. 9 is a configuration block diagram showing a fifth embodiment of the radar apparatus of the present invention. In FIG. 9, reference numerals 1 to 7, 8a, and 9 to 16 are the same as or equivalent to those of the first embodiment shown in FIG. 29 is a priority control means.

Next, the operation will be described. In FIG. 9, the operations of all the units except the priority control unit 29 are as follows.
This is the same as Embodiment 1 shown in FIG. In the fifth embodiment, the priority control unit 29 includes the target sway estimation unit 1.
The control is such that the estimation result of the motion of the observation target of No. 6 is output to the point image response estimating means in order from the motion (motion) corresponding to the Doppler frequency with the highest frequency of appearance.

FIG. 1 shows the operation of the priority control means 29.
0, and will be described with reference to FIG. FIG. 10 is a diagram for explaining an example of a temporal change of the Doppler frequency caused by the movement (oscillation) of the roll and the pitch of the observation target. In FIG. 10, reference numeral 30 denotes a Doppler frequency due to, for example, a pitch motion, and reference numeral 31 denotes a Doppler frequency due to, for example, a roll. Since the phase relationship between 30 and 31 is undefined, these 2
The sum of the two Doppler frequencies is distributed in the region indicated by 32, and the motion of the target is not necessarily determined uniquely. The estimated value of the period and angle amplitude of the roll and the pitch of the observation target is obtained by the target fluctuation estimating means 16. The Doppler frequency of a point is given by the sum of the respective sinusoidal frequency changes caused by roll and pitch.

FIG. 11 is a diagram for explaining an example of the appearance frequency of the Doppler frequency in FIG. In FIG. 10, the time width in which a certain Doppler frequency exists is known, and the appearance frequency of the Doppler frequency is known. As shown in FIG. 11, the appearance frequency of the Doppler frequency generally has a difference. For example, in the example shown in FIG. 11, the appearance frequency of f _d0 is the highest. The priority control unit 29 first outputs the motion corresponding to the Doppler frequency with the highest appearance frequency to the point image response estimating unit 8a to identify the target. Subsequently, the motion corresponding to the Doppler frequency is output to the point image response estimating means 8 in descending order of appearance frequency, and the target is identified in order. When the frequency of appearance is equal to or less than a predetermined threshold, it is possible to control so that the motion corresponding to the Doppler frequency is not identified.

As described above, according to the fifth embodiment of the present invention, in addition to the effect of the first embodiment, the priority control means uses the estimation result of the fluctuation of the observation target as the Doppler frequency having a high appearance frequency. Since the exercise is controlled so as to output to the inspection response estimating means in order from the exercise corresponding to the above, the identification can be realized even if the exercise is not uniquely determined, and the identification performance of the moving water target can be improved. Further, since the discrimination is not performed for the motion corresponding to the Doppler frequency having a low appearance frequency, the calculation time for the discrimination can be reduced.

Embodiment 6 FIG. FIG. 12 is a configuration block diagram showing a sixth embodiment of the radar apparatus of the present invention. In the figure, reference numerals 1 to 7, 8a, and 10 to 16 are the same as or equivalent to those of the first embodiment shown in FIG.
9a will be described below.

Next, the operation will be described. In FIG. 12, the operation of all means except the target aspect angle estimating means is the same as that of the first embodiment shown in FIG. In the sixth embodiment, the target aspect angle estimating means 9a may estimate the target aspect angle based on the target velocity vector output from the target tracking means 7 and the direction of the ocean current or wind in the weather information. It is a feature.

FIG. 13 is a view for explaining the observation geometry of the sixth embodiment. In the figure, reference numeral 17 denotes an observation target. In this figure, it is assumed that the observation target 17 is sailing on the surface of the sea current, and an example is shown in which the sea current is flowing slightly downstream (in the counterclockwise direction in FIG. 13) from the direction of the bow. ing. In the radar apparatuses according to the first to fifth embodiments, the aspect angle between the target and the LOS is estimated based on the target velocity vector of the output of the target tracking means 7, and as shown in FIG. In contrast to the case where a small value is estimated, in the sixth embodiment, the target aspect angle estimating means obtains information on the ocean current from an external system such as weather information or the like described in the second embodiment. The information measured by the water level measuring means of the radar device is obtained, and the estimation error of the aspect angle due to the influence of the ocean current is corrected. In addition, it is possible to obtain wind information from an external system such as weather information, and similarly correct an estimation error of the aspect angle due to the influence of the wind.

As described above, according to the sixth embodiment of the present invention, in addition to the effect of the first aspect of the present invention, the target aspect angle estimating means outputs the target velocity vector of the output of the target tracking means and the weather information. By estimating the target aspect angle based on the direction of the ocean current or wind, the error of the target aspect angle due to the influence of the ocean current or wind direction is corrected, and the automatic recognition and identification performance of the observation target on the oscillating water is improved. Can be improved.

[0079]

As described above, according to the first aspect of the present invention, the target motion estimation means is provided to estimate the motion of the observation target on the water that shakes, thereby greatly reducing the types of motions to be assumed. To generate a reference image to be compared and matched with the radar image.
A radar device that can perform identification in real time can be obtained.

According to the invention of claim 2, according to claim 1,
In addition to the effects of the invention, it is possible to obtain a radar apparatus with improved identification performance of a moving water target by using real-time wave information from a water surface measurement unit that measures the state of the water surface of the observation water area from the received signal. I can do it.

According to the third aspect of the present invention, the first aspect
In addition to the effect of the invention, the image reproduction parameter of the image reproduction means of the radar image of the observation target is adjusted based on the estimation result of the fluctuation of the observation target, so that the image of the cross range axis due to the fluctuation of the observation target is adjusted. It is possible to obtain a radar apparatus in which the blur and cross-range resolution can be kept constant and the discrimination performance of a moving water target is improved.

Further, according to the invention of claim 4, according to claim 1,
In addition to the effect of the invention, the transmission parameters of the transmitter of the radar apparatus are adjusted based on the estimation result of the fluctuation of the observation target, so that it is possible to obtain a radar image without image aliasing and to fluctuate. It is possible to obtain a radar device in which the performance of identifying a water target is improved.

According to the invention of claim 5, according to claim 1,
In addition to the effect of the invention, the priority control means controls to output the estimation result of the fluctuation of the observation target to the inspection response estimating means in order from the motion corresponding to the Doppler frequency with a high appearance frequency. Can be realized even if is not uniquely determined, and it is possible to obtain a radar device with improved identification performance of a moving water target.

According to the invention of claim 6, according to claim 1,
In addition to the effects of the invention, the target aspect angle estimating means estimates the target aspect angle based on the speed vector of the target output from the target tracking means and the direction of the ocean current or wind in the weather information, so that the ocean current or wind By correcting an error of the target aspect angle due to the influence of the direction of the radar, it is possible to obtain a radar device with improved identification performance of a moving water target.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the sway of a water surface observation target and the geometry of a wave according to the first embodiment.

FIG. 3 is a configuration block diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram for explaining an observation geometry of a wave on a water surface according to the second embodiment.

FIG. 5 is a diagram for explaining the principle of measuring the wave period in FIG. 4;

FIG. 6 is a diagram for explaining the principle of measuring the wave height in FIG. 4;

FIG. 7 is a configuration block diagram showing a third embodiment of the present invention.

FIG. 8 is a configuration block diagram showing a fourth embodiment of the present invention.

FIG. 9 is a configuration block diagram showing a fifth embodiment of the present invention.

FIG. 10 is a diagram illustrating an example of a temporal change in Doppler frequency caused by the movement (wobble) of an observation target according to the fifth embodiment.

FIG. 11 is a diagram illustrating an example of the appearance frequency of a Doppler frequency generated by the movement (sway) of an observation target according to the fifth embodiment.

FIG. 12 is a configuration block diagram showing a sixth embodiment of the present invention.

FIG. 13 is a diagram for describing an observation geometry according to the sixth embodiment.

FIG. 14 is a block diagram showing a configuration of a conventional radar device.

FIG. 15 is a diagram for explaining an observation geometry in a conventional radar device.

FIG. 16 is a diagram illustrating an observation geometry in a conventional radar device.

FIG. 17 is a block diagram showing the internal configuration of the image reproducing means 5 shown in FIG.

[Explanation of symbols]

1, 1a transmitter, 2 receiver, 4 transmitting / receiving antenna,
5, 5a image reproducing means, 6 correlation calculating means, 7 target tracking means, 8a point image response estimating means, 9, 9a target aspect angle estimating means, 10 RCS calculating means, 12 convolution integrating means, 13 maximum value detecting means, 14 Target identification result output means, 16 target sway estimation means, 17 observation targets, 26 water level measurement means, 29 priority control means.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuro Kirimoto 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Ken Ashizawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F term in Mitsubishi Electric Corporation (reference) 5J070 AC01 AC02 AC06 AC11 AC13 AC15 AE02 AE07 AH02 AH04 AH14 AH19 AJ13 AK04 AK36 BA01 BB04 BB06 BG02

Claims (6)

[Claims] 1. A radar apparatus for observing a water target such as a ship, an image reproducing means for reproducing a radar image of the observation target from a reception signal of a receiver output, and a distance and an azimuth of the observation target from the reception signal. A target tracking means for measuring the time change of the target to obtain the motion characteristics such as the position, the moving direction and the speed of the observation target; and forming a line-of-sight and a moving direction of the observation target based on the output of the target tracking means. A target aspect angle estimating means for estimating an angle, and a target shaking for estimating the shaking of the observation target based on the output of the target tracking means, the wave state information of the water surface, and a database in which structural parameters of various targets on the water are stored in advance. Estimating means; point image response estimating means for estimating a point image response function of the radar image based on the output of the target tracking means and the output of the target fluctuation estimating means; Means for calculating a radar cross-section distribution on the observation target based on the target aspect angle and a database storing target shape data to be recognized / identified in advance; and a radar cross-section distribution on the observation target and the radar image Means for performing a convolution integral with the point image response function of the above to generate a reference image to be compared and collated with the radar image output from the image reproducing means, and a correlation calculating means for obtaining a correlation between the radar image of the observation target and the reference image And maximum value detection means for specifying a reference image having the maximum correlation, and target identification result output means for reading and outputting target information corresponding to the specified reference image from a target shape database. A radar device characterized by the above-mentioned. 2. The radar apparatus according to claim 1, further comprising a water surface measuring means for measuring and outputting a period and a direction of a wave on the water surface from a reception signal of the radar apparatus. 3. Based on the estimation result of the fluctuation of the observation target,
2. The radar apparatus according to claim 1, wherein an image reproduction parameter of an image reproducing means for reproducing a radar image of the observation target is adjusted. 4. Based on the estimation result of the fluctuation of the observation target,
The radar device according to claim 1, wherein a transmission parameter of a transmitter of the radar device is adjusted. 5. A priority control means for controlling the estimation result of the fluctuation of the observation target to be output to the point image response estimation means in order from the motion corresponding to the Doppler frequency having a high appearance frequency. The radar device according to claim 1, wherein: 6. The radar apparatus according to claim 1, wherein the target aspect angle is estimated based on information from the target tracking means and weather information on the ocean current or the wind.