JPH07181252A - Target tracking device - Google Patents

Abstract

PURPOSE:To obtain a target tracking device with an improved tracking accuracy by performing correlation processing using the position energy and momentum of a ship. CONSTITUTION:The area of an image observed by a radar antenna 1 is obtained by a ship characteristic calculation part 7, the ship characteristic calculation part 7 obtains the area of the image of the ship as the parameter of position energy of the ship, and at the same time it obtains the traveling speed of the ship image according to the image position of the current ship and the previous image position of the ship. Then, the product of the traveling speed of the ship image and the area of the obtained ship image is obtained as the momentum parameter of the ship, a first tracking part 19 stores both parameters as the characteristic parameters of ship, and then the previous characteristic parameter and the current characteristic parameter are correlated for tracking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a target tracking device using a radar, and more particularly to a target tracking device that tracks using the potential energy and kinetic energy of a ship.

[0002]

2. Description of the Related Art FIG. 5 is an explanatory diagram of a tracking processing method. In the figure, Xp (n-1) is the last smoothed position, XS (n) is the predicted position obtained last time, Xp (n) is the smoothed position, XD (n) is the measured position, and XS (n + 1) is Next predicted position, n is sample time, X
i (n) is the observation position. As shown in the figure, the tracking process is the measured position XD (n) and the predicted position X obtained last time.
The positional correlation with S (n) is taken. For example, when there is a positional correlation, based on the measured position XD (n) and the predicted position XS (n) obtained last time, as shown in the following formula, Smooth position X
D (n) is obtained, and the next predicted position XS (n + 1) is obtained and tracked from the smoothed position XD (n) and the previous or past tracking information.

Xp (n) = α × XD (n) + (1−α) × XS (n) where 0 ≦ α ≦ 1 By the way, the basic principle of mechanics is that the temporal change rate of momentum is equal to force. It is represented by the equation of motion of the form. Further, the acting force is the same as the opposite force acting in the opposite direction. And on the earth, the mass m (K
The magnitude of the attractive force acting on the mass point M in g) is F = mg [N]
Is. This force is called the gravity of the earth and g is called the constant of gravity. Further, the potential energy U of the mass m (Kg) at the height h (m) is mgh [J], and the kinetic energy E of the mass m (Kg) moving at the speed V (m / s) is E = 1. / (2mv ² ) [J], these kinetic energy E and potential energy U
The sum of is preserved and constant. And momentum (mv)
Is the product of mass (m) and velocity (v), and the mass of an object is the product of density and volume. If the density is constant, the mass is the volume. Proportional to.

Further, this volume is represented by the product of the length and the cross-sectional area, and if this length is also constant, the mass is proportional to the cross-sectional area.
Then, the speed is expressed by distance / time, and if this time is constant, the speed is proportional to the distance. An object has something called inertia, and its resistance force is called inertial force, which is the product of mass and acceleration. In other words, the position is also determined depending on the above mechanical parameter.

[0005]

The above-described conventional target tracking device performs tracking processing on a target whose position correlation can be obtained. That is, in the target tracking device using the radar of the related art, it is used only as an observing device for the position of the target, and the information is converted into only the position information expressed as a point for tracking. Therefore, actually, the obtained smoothed position, predicted position, or actually measured position is a position having an area that is the product of distance and azimuth, but using mechanical parameters (potential energy and momentum) However, there is a problem that the tracking result becomes unstable. In other words, processing was performed with the available information missing, and no technically satisfactory information was obtained. The present invention has been made to solve the above problems, and an object of the present invention is to obtain a target tracking device in which tracking accuracy is improved by performing correlation processing using the potential energy and momentum of a ship.

[0006]

A target tracking apparatus according to the present invention supplies transmission power to a radar antenna at predetermined intervals and receives an image based on a received signal from the target received by the radar antenna. In the radar system that displays on the display screen corresponding to the position based on the time and the angle of the radar antenna, the position of the image is stored, the moving speed is calculated based on the position of the previous image and the position of the current image, and The area is obtained, the product of the moving speed and the area of the image is obtained as the parameter of the momentum of the target, and the area of the image is obtained as the parameter of the potential energy of the target. The ship characteristic calculation unit that obtains the ship characteristic parameter and the ship characteristic parameter from the ship characteristic calculation unit are stored as tracking information, and the characteristic parameters of the ship are stored as tracking information. The smoothing position of this time is obtained based on the characteristic parameter of the previous ship, and the first tracking unit that predicts the next position based on this smoothing position, and the video code based on this tracking information are created, and the video code is calculated. And an image creation unit for displaying the image on the display screen based on the smoothed position. Further, instead of the first tracking unit, when the position correlation between the position of the image and the predicted position obtained last time is obtained, correlation determination is performed by adding the characteristic parameter of the ship obtained by the ship characteristic calculation unit, and the smooth position is calculated. And based on this smooth position,
It is provided with a second tracking section for obtaining the next predicted position.

[0007]

In the present invention, the area of the image of the ship observed by the radar is obtained, the area of the image is obtained as a parameter of the potential energy of the ship, and the image position of the current ship and the previous image position The moving speed of the image is obtained, and the product of the moving speed of the image and the obtained area of the image is obtained as the parameter of the momentum of the target. Both of these parameters are stored as the characteristic parameters of the ship. In order to correlate with the ship's characteristic parameters, the correlation is tracked to correlate with the ship's potential energy and momentum. Further, when the position correlation between the position of the ship image and the previously calculated predicted position is obtained, since the correlation determination is performed by adding the calculated characteristic parameter of the ship, the judgment amount of the position correlation and the judgment amount of the characteristic parameter of the ship are The added smoothed position is obtained, and the next predicted position is obtained based on this smoothed position.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention does not consider that the position of the target obtained by the radar is actually a position having an area rather than a point, and the tracking is performed by using the basic principle of dynamics. In order to eliminate the fact that the tracking result became unstable due to the lack of the amount of information to be handled in tracking, the potential energy of the ship was calculated based on the ship echo area observed by the radar and its traveled distance. In addition to the conventional correlation processing of ship echo position by calculating the momentum of kinetic energy, it also provides a method of correlation processing of the newly obtained energy value of the ship, and adopts an optimal echo compared to conventional tracking In order to achieve stable tracking, the embodiment will be described below.

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention. In the figure, 1 is a radar antenna, 3 is a transmitting / receiving unit, and 5 is a display unit. Reference numeral 7 is a ship feature calculation unit. The ship characteristic calculation unit 7 has at least the following configuration. Reference numeral 9 is a speed calculation unit. The speed calculator 9 is the transmitter / receiver 3
Depending on the antenna angle and the radio wave arrival time of the received data (including the antenna angle, the radio wave arrival time, the reflected signal) from
The position XD (n) of the target (hereinafter referred to as the ship) is calculated, and the ship image velocity VE (n) is calculated based on the positional relationship with the previous XD (n-1) that correlates to this position XD (n). . Reference numeral 11 is an image area calculating means. The image area calculation means 11 obtains the image area SE (n) of the ship based on the reflection signal from the received data, and outputs this image area SE (n) as a parameter proportional to the potential energy of the ship. Reference numeral 13 is a momentum calculation means.
The momentum calculating means 13 outputs the product of the image area SE (n) of the ship and the image speed VE (n) of the ship as a motion parameter proportional to the momentum of the kinetic energy of the ship. Reference numeral 17 is a ship feature specifying means. The ship characteristic determining means 17 specifies the characteristics of the ship image (hereinafter referred to as ship parameter) based on the obtained parameters of the potential energy of the ship and the motion parameters. Reference numeral 19 is a first tracking unit.
The first tracking unit 19 has energy correlation means 23 that sequentially stores the obtained ship parameters as tracking information in the memory 21 and determines the previous ship parameters that are correlated with the current ship parameters. The smoothed position XD (n) of this time is obtained from the ship parameters, and the next predicted position X is calculated from this smoothed position XD (n) and the previous or past tracking information.
Track for S (n + 1). At this time, since the kinetic energy correlating unit 7 has notified which of the previous received data that is kinematically correlated, even if the position correlation is simply taken, the kinematically based position correlation is performed. Will be. Reference numeral 25 is a video creation unit. Video creation unit 25
When the smoothed position of the radar antenna 1 for each rotation is obtained, the video code is created based on the tracking information and output to the display unit 5.

The target tracking device configured as described above will be described below. FIG. 2 is an explanatory diagram of correspondence between a ship and radar images of the ship. (A) of the figure shows a schematic diagram of a ship which is a moving object, L is the ship length, S is the cross-sectional area of the ship,
W is the ship width and H is the ship height above the sea level. (B) of the figure shows the radar image of the ship of (a) obtained by the radar, SE is an echo image (ship image) obtained when a radio wave is emitted to the ship, and LE is a ship image SE.
, WE is the width of the ship image SE. Then, as shown in the figure, the radar image of the ship corresponds to the ship length L, the cross-sectional area S of the ship, and the ship width W. next,
The relationship between the momentum and mass of the ship shown in FIG. 2A will be described below. FIG. 3 is an explanatory diagram illustrating the relationship between the momentum and the mass of the ship. The figure shows, for example, an approximate three-dimensional shape of the ship shown in FIG. 2 (a). Since the ship is floating on the water surface, the height from the water surface may be constant,
Further, since the height H from the water surface, the mass m and the width W, and the volume density (hereinafter simply referred to as density) of the ship do not change, the potential energy of the ship is always constant even if the ship is moving. is there. However, when the ship is moving, the speed V generally changes. That is, the only parameter that changes with time is the velocity V.

The mass of the ship is generally based on the size of the ship. Therefore, the ship changed,
If the size is different and the ship moves at the speed V in the same manner, the product of the cross-sectional area S of the ship and the moving speed V is different from the product of the cross-sectional area of the ship and the moving speed. . Further, the momentum of the ship is indicated by the product of the mass m of the ship and the moving speed V of the ship,
If only the mass of the ship changes, the momentum (m
V) is also different. Therefore, the momentum (mV) of the ship is the cross-sectional area S of the ship and its moving speed V.
Is proportional to the product of Further, the area SE of the ship image by the ship echo shown in FIG. 2B corresponds to the cross-sectional area S of the ship, and the moving speed VE of the ship image obtained with the movement of the ship image is generally the ship speed V. The product of the area SE of the ship image and the moving speed VE of the ship image is proportional to the momentum (mV) of the ship.

Therefore, the product of the obtained area SE of the ship image and the moving speed VE of the ship image is a value corresponding to the momentum of the kinetic energy of the ship, and the area SE of the ship image is a value corresponding to the potential energy of the ship. If the momentum and potential energy (collectively, ship parameters) based on this ship image are the characteristics of the ship, when there are multiple ships in the monitoring area and the tracking process of a specific ship is performed, the position correlation as in the past is used. Even if tracking is not performed by the processing, the tracking processing described above can be performed by the correlation of the ship parameters described above, so that tracking accuracy is improved. Therefore, in this embodiment,
The speed calculating means 9 calculates the moving speed VE of the ship image, the momentum calculating means 13 calculates the product of the moving area VE and the image area SE of the ship, and this value is used as the motion parameter associated with the movement of the ship in the ship feature specifying means 17. Output.

Then, the ship feature specifying means 17 specifies the ship feature based on the product of the parameter of the image area SE (n) corresponding to the potential energy of the ship and the motion parameter, and the tracking section 19 determines this ship. Tracking processing is performed based on the ship parameter indicating the feature and the previous ship parameter that is correlated. In other words, by using the echo area of the ship observed by the radar and its travel distance (when the speed is determined), the energy of the position of the ship and the energy of motion are calculated, and the input echo that matches this energy is adopted. It is designed so that it can be tracked. Also,
In addition to the conventional position correlation, tracking may be performed by correlation of ship energy parameters (ship parameters).
This tracking will be described below with reference to the drawings.

FIG. 4 is a schematic configuration diagram of the second embodiment.
In the figure, 1 to 25 are the same as above. Thirty
Is a second tracking unit. The second tracking unit 30 sequentially stores the obtained ship parameters in the memory 21, and finds a previous ship parameter that correlates with the current ship parameter by the energy correlating unit 23 and the ship parameter in the memory 21 based on the position correlation. The determination unit 34 has a correction unit 32 for correcting the position when the position correlation is present, and based on the measured position XD (n) of the correlation position determined by the position correlation determination unit 34, the current smoothed position XD (n) is obtained, and the next predicted position XS (n + 1) is obtained from the smoothed position XD (n) and the previous or past tracking information to perform tracking. Therefore, since the previous received data that is kinematically correlated is informed, even if the position correlation is simply obtained, it means that the position correlation is based on kinematics.

That is, according to the present invention, the echo area of the ship and its moving speed observed by the radar are obtained, and the value of the potential energy of the ship is proportional to the echo area, and the value of the kinetic energy (momentum) of the ship is echoed. It is more optimal than the conventional tracking based on the position-only correlation by newly adding the processing of the correlation of the ship energy value in the same manner as the position correlation of the prior art by using the proportionality to the area and its moving speed. Stable tracking is adopted by adopting such an echo, and in the prior art, the processing method regarding the value of the energy of the ship was unknown, and there was no choice but to track only by the correlation of the position while leaving that information missing, Since the present invention doubles the amount and quality of information, more stable tracking can be realized. Further, it can be understood that the processing cycle is constant, and that the moving speed (v) of the ship can be considered to be substantially constant before and after the processing if it is a short time.
Actually, although there is an error between the predicted speed and area and the actually measured speed and area, this correlation processing is also similar to the position correlation of the prior art.

[0016]

As described above, according to the present invention, the area of the image of the ship observed by the radar is obtained, the area of the image of the ship is obtained as a parameter of the potential energy of the ship, and the image position of the ship at this time is obtained. Then, the moving speed of the ship image is obtained from the previous image position of the ship, and the product of the moving speed of the ship image and the area shape of the obtained ship image is obtained as a parameter of the momentum of the ship. Since it is stored as a characteristic parameter and the tracking is performed by correlating the characteristic parameter of the previous time and the characteristic parameter of the current ship, since the information of the momentum of the past potential energy and kinetic energy of the ship is inherited,
The effect that the tracking accuracy is improved and stable tracking can be achieved is obtained as compared with the conventional tracking based on the correlation only with the position. Also, when the position correlation between the position of the ship image and the previously calculated predicted position is obtained, correlation is judged by adding the characteristic parameter of the calculated ship, the smooth position is calculated, and the next prediction is performed based on this smooth position. Since the position is obtained, the effect that the tracking accuracy is further improved is obtained.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of correspondence between a ship and radar images of the ship.

FIG. 3 is an explanatory diagram illustrating the relationship between the momentum and mass of a ship.

FIG. 4 is a schematic configuration diagram of a second embodiment.

FIG. 5 is an explanatory diagram of a tracking processing method.

[Explanation of symbols]

 1 Radar Antenna 3 Transmitter / Receiver 5 Display 7 Vessel Characteristic Calculator 9 Velocity Calculator 11 Video Area Calculator 13 Momentum Calculator 17 Ship Characteristic Specifier 19 First Tracker 23 Energy Correlator 25 Video Creator 30 Second Tracking unit

Claims (2)

[Claims] 1. A transmission power is supplied to a radar antenna at predetermined intervals, and an image based on a received signal from a target received by the radar antenna corresponds to a position based on a reception time and an angle of the radar antenna. In a radar system to be displayed on a display screen, the position of the image is stored, the moving speed is obtained based on the position of the previous image and the position of the current image, the area of the image is obtained, and the moving speed and the image are obtained. Is calculated as a parameter of the momentum of the target, and the area of the image is calculated as a parameter of the potential energy of the target, and a ship characteristic calculation unit for calculating a characteristic parameter of the ship based on these parameters And storing the characteristic parameters of the vessel from the vessel characteristic calculation unit as tracking information, and correlating them with the characteristic parameters of the vessel this time. The first tracking unit that obtains the current smoothed position based on the characteristic parameters of the ship and predicts the next position based on the smoothed position, and a video code based on the tracking information is created. A target tracking device, comprising: a video creating unit for displaying on the display screen based on a smooth position. 2. When the position correlation between the position of the image and the predicted position obtained last time is taken instead of the first tracking unit, the correlation is performed by adding the characteristic parameter of the ship obtained by the ship characteristic calculation unit. The target tracking device according to claim 1, further comprising a second tracking unit that determines and determines a smoothed position and, based on the smoothed position, a next predicted position.