JPH01201181A - Moving target tracking device - Google Patents

Abstract

PURPOSE:To extract numbers of targets in real time by providing a distance window table which stores prediction range data in the distance directions of the targets by unit angles over the prediction range of angle directions. CONSTITUTION:A target extraction processing part 100 has a distance window table constituted in a specific area of a RAM 9 and a CPU 8 reads data out of a distance data stack 20 and a direction counter 7 according to the program in a ROM 10 and also extracts a target from the distance window table. A CPU 12 finds the predicted position, etc., of the target according to target extraction data outputted by the target extraction processing part 100. Thus, the linear distance window table is used to track the target, so the arithmetic processing required for the tracking is simplified and even when the number of targets to be tracked increases, the target extraction by the window is performed in real time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a moving target tracking device that measures the position of a target and tracks the target by transmitting and receiving traveling waves such as radio waves and sound waves.

(b) Conventional technology Conventionally, for example, in collision prevention systems using radar,
In addition to measuring the positions of other ships and other targets around the ship at regular intervals, it also tracks each target to determine its direction and speed of movement.

In order to track each target in real time by measuring the positions of a plurality of targets at regular time intervals in this way, the processing time for tracking must be short. For example, if the antenna makes one revolution in 2 seconds and 2000 pulses are generated during that time, the target must be extracted within 1 m5eC.

For this reason, conventional methods calculate a window with a predetermined spread corresponding to the predicted position of the target to be detected next time, and check whether the position (distance, angle) of the detected target is within this window. The target object is tracked by determining whether or not the window exists and extracting the target object that exists within the window.

(C) Problem to be solved by the invention However, since the window is a two-dimensional window with a constant width in both the distance direction and the angular direction,
Determining whether or not the position (distance, angle) of the detected target exists within the window requires a lot of calculation processing and takes a long time. Therefore, if a large number of windows are created, it is difficult to perform tracking processing in real time, and the number of targets that can be tracked is limited to a small number.

An object of the present invention is to provide a moving target tracking device that can track a large number of targets by reducing the number of calculations required for real-time processing.

(Means for Solving Problem d1) The moving target tracking device of the present invention includes a target position measuring means for measuring the polar coordinate position of the target by transmitting and receiving traveling waves in the radial direction centering on an observation point. , a distance window table that stores predicted range data in the distance direction of the target object for each unit angle within the predicted range in the angular direction; and reading distance window data corresponding to the angular direction of arrival of the reflected wave from the distance window table;
Target extraction means for extracting a target existing within a distance window based on distance data of the target obtained by the target position measuring means; Deleting distance window data regarding the extracted target from a distance window table and extracting it. The present invention is characterized by being provided with distance window table updating means for writing predicted range data in the distance direction into the distance window table for each unit angle within the predicted range in the angular direction based on new position data of the target object.

fe+ Effect FIGS. 1 to 3 are diagrams for explaining the effect of the moving target tracking device of the present invention.

Figure 1 shows the relationship between each means. The target position measuring means measures the polar coordinate position of the target by transmitting and receiving traveling waves in a radial direction centered on the observation point, and obtains distance data and angle data. The distance window table stores predicted range data of the target in the distance direction within the predicted range in the angular direction for each unit angle. The target extracting means reads the data of the distance window table selected by the angle data, and extracts the target existing within the distance window based on the distance data. The distance window table updating means deletes the distance window data regarding the extracted target from the distance window table, and updates the predicted range data in the distance direction in units within the predicted range in the angular direction based on the new position data of the extracted target. Write to the distance window table for each angle. FIGS. 2 and 3 show specific examples of the contents of the target position and distance window table. Second
In the figure, A and B represent the positions of targets, respectively. Target A is located at a distance of 20 miles and an angle of 10 degrees, and target B is located at a distance of 21 miles and an angle of 11 degrees. ± distance window
If the distance is 0.3 miles, the contents of the distance window table will be as shown in FIG. 3, for example. Here, the unit angle is 1 degree, and the predicted range of the angular direction is ±1 degree. Therefore, for target A, distance window data of 20 miles in distance and ±0.3 miles in width are stored at 9 degrees, 10 degrees, and 11 degrees, and for target B, distance window data is stored at 9 degrees, 10 degrees, and 11 degrees.
Distance window data of a distance of 621 miles and a width of ±0.3 miles are stored for each of degrees and 12 degrees.

In the example of the distance window table above, if the measurement result of the target position measuring means shown in Figure 1 is, for example, a distance of 20.2 miles and an angle of 11 degrees (point A' in Figure 2), the target is extracted. The means recognizes that this is target A by extracting distance window data including 20.2 miles from the distance window data at 11 degrees in the distance window table shown in FIG. Thereafter, the distance into-table updating means deletes the distance window data regarding the target A from the distance window table and writes new distance window data centered on the position A' of the target A.

By making the window only one-dimensional in the distance direction in this way, the process of target extraction using the window is simplified and a large number of targets can be extracted in real time. Note that it is necessary to convert a window having a certain extent in the distance direction and angular direction into one-dimensional one, but this process can be completed within one period of the antenna, for example.
Real-time performance is not required.

Embodiment FIG. 4 is a block diagram of a moving target tracking device according to an embodiment of the present invention, and FIGS. 5 to 7 are flowcharts showing processing procedures of each CPU in FIG. 4.

In FIG. 4, a pulse generating circuit 1 is a circuit that generates a timing pulse for emitting radio waves from an antenna 3, and a transmitting circuit 2 is triggered by this pulse signal to cause the antenna 3 to emit radio waves. The receiving circuit 4 is a circuit that receives reflected waves received by the antenna 3, and outputs a trigger signal to the distance data stack 20 if there is an echo. The distance counter 5 is triggered by a pulse generated from the pulse generating circuit 1 and counts a value corresponding to the distance from the reflecting object. The distance data stack 20 is a circuit that sequentially stores the data of the distance counter 5 every time a trigger signal is generated from the receiving circuit 4.

The antenna drive circuit 6 is a circuit that rotationally drives the antenna 3, and the direction counter 7 is a circuit that counts a value corresponding to the direction of the antenna (for example, the direction of the antenna with north as a reference). 100 is a target extraction processing unit which outputs an interrupt signal INT to the CPU;
A distance window table is configured in a specific area of the RAM 9, and the CPU 8 reads data from the distance data stack 20 and direction counter 7 according to the program in the ROM 10, and extracts targets from the distance window table. This processing is performed by interrupt processing, which will be described later, when the output signal INT of the direction counter 7 is generated. 1
01 is a processing unit for target tracking, and CPU12 is a ROM1
According to the program No. 3, the estimated position of the target is determined based on the target extraction data output from the target extraction processing section 100. Note that the RAM 14 is used for temporary storage of target extraction data output from the target extraction processing section 100. 102 is a table update processing unit that updates the distance window table, and the CPU 16 updates the distance window table based on data such as the current position of the target output from the target tracking processing unit 101 according to the program in the ROM 17. I do.

FIG. 5 is a flowchart showing the processing procedure of the CPUA, and when the direction counter 7 generates the interrupt signal INT, this interrupt processing is performed. First, the antenna direction θ is read from the direction counter 7, and it is determined whether data exists in the distance data stack 20 (nl-n2). If data exists in the data stack 20, the distance data r is read (n3). Next, when reading data from the table slot of the distance window table, reset i, which is used as a data pointer, and read data from the distance window table (n4→n
5). Here, the distance window table is basically the third
As shown in the figure, the unit angle is (360/2000) Jf, assuming that 2000 pulses are generated by one round of the antenna. In addition, 10 distance window data can be stored for each unit angle.
Individually.

After that, calculate the difference between the table distance data rd and the measured distance data r, and if the value is less than the table width data W, read out the measured target position (distance r, circumferential angle) and the table. The target object code is output to the target object tracking processing unit 101 (n6→n7).

If the absolute value of rd-r is greater than or equal to W, it is assumed that the table data is valid and i is incremented.
Read the following table data and perform a similar comparison (
n8→n9→n5). This process continues until i=10.
That is, all the table data at the angle θ are compared.

Note that the series of processes shown in FIG. 5 is completed within the radio wave emission interval, for example, 1 m5 ec.

The CPU 12 of the target tracking processing section 101 performs processing according to the procedure shown in FIGS. 6(A) and 6(B). As shown in FIG. 6(A), the data output from the target object extraction processing section 100 is inputted by interrupt processing and accumulated at - time. Then, as shown in Fig. 6 (CB) except during interrupt processing, the stored target object extraction data is sequentially read out, and this latest target position data is filtered to determine the current position of the target (r c, θC ) (n10→n11
). Furthermore, based on the accuracy of the current target position, the window size, that is, the width in the distance direction Δr and the width in the angular direction Δθ
is calculated and outputs the target code together with these data to the table update processing unit 102 (n12→n13). The above processing is sequentially performed on newly input target extraction data.

The CPU 16 of the table update processing section 102 performs processing according to the procedure shown in FIG. The estimated target position (rc, θC), window size (Δr, Δθ), and target code are read from the target tracking processing unit 101 (n14).
, the window data regarding this target is deleted from the distance window table (n15). Further, prediction range data in the distance direction represented by rc and Δr is written in the distance window table for each unit angle over the angle range defined by θC and Δθ read in n14 (n1
6). The above processing is performed every time data is read from the target tracking processing unit 101.

The series of processes shown in FIGS. 6(B) and 7 described above are completed within one period of the antenna, for example, 2 seconds.

In the embodiment, the target object extraction processing section gave the extracted target data to a single target tracking processing section, but even if there are multiple target tracking processing sections, each of them can perform the requested object data. Target extraction data in the window can be passed to each.

In addition, although the example uses a radar device to track a target such as another ship, the present invention can be similarly applied to other cases where a sonar device is used to track an underwater target such as a school of fish. Can be done.

(g1 Effects of the invention As described above, according to this invention, since the target object is tracked using a -dimensional distance window table, the arithmetic processing necessary for tracking is simplified, and the object to be tracked is Even if there are a large number of targets, target extraction can be performed in real time using a window.

Further, since a window having an arbitrary size can be set for each target object, tracking according to the movement characteristics of the target object is possible.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams for explaining the invention in detail, with Figure 1 showing the configuration of the invention, Figure 2 showing examples of targets and windows, and Figure 3. shows an example of a distance window table. FIG. 4 is a block diagram of a moving target tracking device according to an embodiment of the present invention, and FIGS. 5 to 7 are flowcharts showing processing procedures of the device.

Claims (1)

[Claims] (1) A target position measuring means that measures the polar coordinate position of a target by transmitting and receiving traveling waves in the radial direction centered on an observation point, and a means for measuring the target's predicted range in the distance direction and the predicted range in the angular direction. a distance window table stored for each unit angle within the range, and reading distance window data corresponding to the direction of the arrival angle of the reflected wave from the distance window table,
Target extraction means for extracting a target existing within a distance window based on distance data of the target obtained by the target position measuring means; Deleting distance window data regarding the extracted target from a distance window table and extracting it. a distance window table updating means for writing predicted range data in the distance direction into a distance window table for each unit angle within the predicted range in the angular direction based on new position data of the target object. Target tracking device.