JPH0412827B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for displaying images of various types of polar coordinate display devices in which directions are expressed in various formats on a single orthogonal coordinate display device. The present invention relates to a direction recognition method suitable for.

[Prior Art] As a conversion display device for displaying polar coordinates to orthogonal coordinates, there is one shown in FIG. 2, for example. What is shown in this figure is an example used in a radar device.

In FIG. 2, antenna 50 is connected to an analog-to-digital converter 52, where the heading signal is converted to a digital signal.

Next, the analog-to-digital converter 52 is connected to the SIN/COS converter 56 of the scan converter 54, and the SIN/COS converter 56 is connected to the coordinate converter 58.
It is connected to the. Above SIN/COS converter 5
6. Coordinate data in rectangular coordinate display is now calculated from the digitized azimuth signal, that is, coordinate data in polar coordinate display, by the scan conversion unit 54 constituted by the coordinate conversion unit 58. There is.

Next, the coordinate conversion unit 58 is connected to the video memory 60, and output data indicating the converted coordinates of the coordinate conversion unit 58 is inputted as address data to the video memory 60. The video memory 60 displays the orthogonal coordinates.
Connected to CRT62.

On the other hand, a transceiver 64 is connected to the antenna 50. Radio waves are emitted from the antenna 50 based on the trigger signal generated within the transceiver 64, and the radio waves reflected by the observation object are received, and the video signal of the object is sent to the transceiver 64 along with the trigger signal. It is now output from . The trigger signal is input to a clock circuit 66, and the video signal is input to an analog-to-digital converter 68.
has been entered.

Next, the clock circuit 66 is connected to the coordinate conversion section 58 of the scan conversion section 54, and the clock signal generated based on the trigger signal is sent to the coordinate conversion section 58.
It is now entered into .

Analog-to-digital converter 68 is connected to video memory 60 via buffer memory 70. In this buffer memory 70, for example, a video signal for one sweep corresponding to one trigger signal is temporarily stored in the real time of signal reception at the transceiver 64, and is read out at a predetermined timing and stored in the video memory. 60.

A synchronization circuit 72 is connected to each of the video memory 60 and CRT 62, and an address signal for reading out the stored video signal is sent to the video memory 60.
The synchronizing signal is output to the CRT62. The address signal is output in response to the synchronization signal output.
Cartesian coordinate display is performed on the CRT 62 based on the video signal stored in the video memory 60.

Next, the operation of the above device will be explained. Generally, radar images are expressed in polar coordinates, that is, angles and distances from the center. In contrast, CRT
62 is a rectangular coordinate display. Therefore, the scan converter 54 performs coordinate conversion of the display position of the video signal.

An azimuth signal representing the angular position of the antenna 50 is converted into a digital signal by an analog-to-digital converter 52 and input to a SIN/COS converter 56, where the values of COS and SIN at the angle are determined.

Then, based on this value, the coordinate conversion unit 58 determines the orthogonal coordinate values of the sampling points of the video signal on the angle. At this time, the distance of the sampling point from the center of the polar coordinates is given by the output signal of the clock circuit 66.

The orthogonal coordinate values obtained by the coordinate conversion section 58 as described above are input to the video memory 60 as a write address.

On the other hand, the video signal at each coordinate is converted into a digital signal by an analog-to-digital converter 68, stored once in a buffer memory 70, and then input to the video memory 60. At this time, a signal is output from the clock circuit 66 so that the operating timing of the analog-to-digital converter 68 corresponds to the operating timing of the coordinate conversion section 58. By this operation, the video signal of the corresponding orthogonal coordinate value is stored in each address of the video memory 60.

Next, the video signal stored in the video memory 60 is read out at high speed in synchronization with the scanning of the CRT 62 by the read address signal output from the synchronization circuit 72, and is input to the CRT 62 to display high-brightness signals based on orthogonal coordinates. Display is performed.

[Problems to be Solved by the Invention] By the way, the direction signal output from the antenna 50 may be a synchro signal, a resolver signal, or
It varies depending on the model, such as a pulse signal using a shaft encoder, which is used recently because it is inexpensive.

However, especially in the case of a remote display, it is desirable to be able to connect to various radars, but if the format of the direction signal of the radar to be connected differs, the conversion device must also be changed. conversion equipment is required.

In this case, an S/D converter or an R/D converter is used to digitize the synchronization signal or the resolver signal from the viewpoints of being able to select a wide range of input signals and of accuracy and reliability.

On the other hand, in the case of a pulse type direction signal, the third
A pulse counter method as shown in the figure is generally used. In FIG. 3, the counter 74 is reset and cleared by a zero degree signal serving as a reference, and is counted up by a pulse signal inputted thereafter.
Then, the count value is output as angle data.

However, even if such a conversion device as described above is used, it is necessary to align the angular units per bit for the azimuth signal in the operation conversion section.

For example, as the S/D and R/D converters mentioned above, 12-bit binary type converters are usually used, and the minimum unit corresponds to 0.0878 degrees. On the other hand, in the case of the pulse method, the number of pulses per radar rotation varies, such as 360, 450, 1080, 1024, etc., and when one rotation is expressed as 360 pulses,
The pulse is 1 degree, and in 450 pulses, 1 pulse is
0.8 degree, even with 1024 pulses it is 0.35 degree.

Next, for example, in the case of a pulse method, when one rotation is expressed by 360 pulses, one pulse is 1
If this alone is used as azimuth data, the accuracy of coordinate transformation will be significantly impaired.

However, in order to realize this improvement in angular accuracy using a circuit, complicated logic is required, and there is a disadvantage that the logic needs to be changed if the rotation angle per pulse is different.

The present invention has been made in view of these points, and provides an azimuth recognition method suitable for a device that displays a plurality of images displayed in polar coordinates based on azimuth signals having different representation formats in a single orthogonal coordinate format. Its purpose is to

[Means for Solving the Problems] The present invention focuses on the fact that a calculation means (CPU) is used in recent radar devices, collision prevention assist devices (ARPA), etc., and uses this calculation means to calculate orthogonal coordinates. It is intended to obtain a single orthogonal coordinate data in the display.

The present invention provides a form instruction means for instructing the form of azimuth data, a data interpolation means for interpolating data according to the form of the azimuth data during data conversion, and obtaining interpolated azimuth data; and data conversion means for performing data conversion using the interpolated azimuth data in accordance with the form specified by the form instruction means to obtain the orthogonal coordinate data. It is something.

[Effect] The format of the orientation data of the target polar coordinate display is
It is indicated by the form indicating means.

The data interpolation means performs interpolation of azimuth data according to the input azimuth data. The orientation data to be interpolated is orientation data at an angle other than the input orientation data.

Cartesian coordinate data in a single form is obtained by a data conversion means using input azimuth data and interpolated azimuth data.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the invention. In this figure, an analog-to-digital converter 10 to which an azimuth signal is input is connected to a buffer circuit 12.
The direction signal is digitized and temporarily stored in the buffer circuit 12.

The analog-to-digital converter 10 converts S/D according to the format of the azimuth signal of the device to be displayed.
Either a D converter, an R/D converter, or a pulse counter is selected.

The buffer circuit 12 is connected to the data bus 16 of the CPU 14, and when the CPU 14 receives an interrupt signal such as a transmission trigger signal,
Raw orientation data is read from the buffer circuit 12.

Next, a setting switch 18 is connected to the data bus 16 of the CPU 14, and the setting switch 18 is designed to specify which form the raw orientation data is in.

Furthermore, a processing table 20 is connected to the data bus 16.
are connected as necessary, and are referenced as necessary by the CPU 14 and used for processing direction data.

The processed standard orientation data is transferred to the data bus 16.
The signal is temporarily stored in a latch circuit 22 connected to the scan converter 24, and then input to the scan converter 24. This scan converter 24 corresponds to the scan converter 54 in FIG. 2 and has similar functions.

Next, the operation of the above embodiment will be explained. In this embodiment, the following processing is performed on various raw orientation data to obtain standardized orientation data. Then, this standard orientation data is converted to obtain position data for orthogonal coordinate display, that is, orthogonal coordinate data corresponding to the address data of the video memory 60.

First, a method for standardizing the format of orientation data will be explained.

Generally, the output of an S/D converter or R/D converter is a pure binary type, and the output is 10 or more.
It is 12 bits. If it is 12 bits, the MSB is
If it is 180°, then 360/2 ¹² = 0.0878°,
0.0878° per LSB bit.

On the other hand, in the case of the pulse method, if it is of the type with 1024 to 2048 pulses/rotation, it can be handled in the same way as ²¹² type data by multiplying it by a power of 2 to obtain azimuth data. In addition, in the case of a type that is not a power of 2 such as 360 or 450 pulses/rotation, if the number of pulses per rotation is N and the direction at pulse count M is D (degrees), then D = (360/ It can be expressed as N)×M...(1).

On the other hand, if we express this direction D in 2 ¹² type, D=360/4096×d...(2), and d is the number of counts when one rotation is 4096 pulses, so d=4096/N× M...(3) If we convert the count number M to 2 ¹²
It can be used as the type of orientation data d.

Next, interpolation of orientation data will be explained. In the case of radar, the number of repetitions of the transmitted pulse is 500 or more.
4000PPS, and the antenna generally rotates smoothly at 24 rpm, or about 2.5 seconds per rotation. Even in the case of 500pps, which is the lowest number of transmission repetitions, the azimuth accuracy of video data is 360°÷1250=0.288°...(4).

However, if the number of pulses output per antenna rotation is 360 or 450 pulses,
The angle is 1° or 0.8° per pulse, and the azimuth interval becomes large, so the display accuracy is not necessarily good.

Therefore, an azimuth corresponding to a trigger signal is set and interpolated between the azimuths specified by each pulse, and video data existing between them is effectively utilized.

Next, interpolation of the orientation data as described above will be described in detail with reference to FIGS. 4 and 5.

Figure 4 shows the direction data per rotation of the antenna.
The interpolation time chart is shown in the case of 360 pulses and the standard azimuth data for the necessary coordinate transformation is 500 Hz, and Figure 5 shows the flow chart of the interpolation calculation procedure. .

Assuming that one rotation of the antenna takes about 2.5 seconds,
Approximately three trigger pulses are input to the CPU 14 during one pulse period of the azimuth data (see FIGS. 4A and 4C).

In this example, the analog-to-digital converter 10 is composed of a pulse counter, and counting is performed every time the azimuth data pulse shown in FIG. 4A is input (see FIG. 4B).

Here, without interpolation, count values M1, M
If only the 2nd class is used as direction data,
The azimuth values of the video signals V1, V2, etc. (see D in the same figure) at times T1 and T2, etc. in the same figure (see C in the same figure) are the same as those indicated by the count value M1, but are actually different azimuths. Even though the video data is in the same direction, it is treated as video data in the same direction.

Therefore, the conversion formula in equation (3) is replaced with d=4096/n×m...(5) n=N×k...(6) m=k×M+i...(7). Here, k is a multiple indicating how many transmit trigger pulses are present between azimuth data pulses. In the example of FIG. 4, k=3 (see A and C in the same figure).

As shown in the flowchart of FIG. 5, first, when the count data M changes,
Adopt a new M with i=0 (step in the same figure)
(See SA, SB). For example, at time T4, the count data changes from M1 to M2, so M2 is adopted (see FIG. 4B).

Next, when there is no change in the count data M,
By incrementing the previous value of m by 1, the direction data is advanced in a pseudo manner (see step SC in FIG. 5).

Through the above operations, the azimuth accuracy of the 360 pulses of the present invention is improved to three times the azimuth accuracy, which is equivalent to 1080 pulses. Similarly, for other pulse numbers, the magnification k of n and m may be selected using the setting switch 18.

The orientation data whose format has been changed and the necessary interpolation performed by the CPU 14 as described above, that is, the standard orientation data, is input to the scan converter 24 via the latch circuit 22. Then, the scan converter 24
By calculating or referring to the processing table 20,
The SIN and COS values of that direction are determined, and furthermore, the orthogonal coordinate values are determined.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, the analog-digital converter 10 and buffer circuit 12 of the embodiment shown in FIG. 1 are replaced with analog-digital converters 30, 32 and a selector 34.

In FIG. 6, the first form of orientation data is
The second form of orientation data is adapted to be input to an analog-to-digital converter 30 , and the second form of orientation data is adapted to be input to an analog-to-digital converter 32 .

The analog-to-digital converters 30 and 32 are
Each is connected to the selector 34, and the CPU 14
Any one of the azimuth data is output to the data bus 16 according to a command from the controller.

Further, the CPU 14 is provided with a changeover switch 36, and by switching the changeover switch 36, a command to change over the selector 34 is issued.

In this example, even if different types of azimuth data are input, they can all be displayed orthogonally by operating the changeover switch 36 and selecting and processing them with the selector 34.

If further required, a third, fourth, etc. converter may be connected and an appropriate one may be selected depending on the format of the input direction data.

Note that the present invention is also effective when a plurality of images displayed in polar coordinates based on azimuth data of different formats are simultaneously displayed in orthogonal coordinates on a single device.

[Effects of the Invention] As explained above, according to the present invention, even if the azimuth data is in various forms, it is converted into standardized azimuth data, and the azimuth data is interpolated as necessary. , has the following effects.

(1) Even if it is connected to a radar with a different orientation data format, it can be easily handled without changing the circuit configuration of the device.

(2) Even if the accuracy of the orientation data is lower than the display capability of the display device based on orthogonal coordinates, by performing interpolation, it is possible to avoid a significant decrease in the display capability of the device.

(3) It is possible to easily select and switch between different types of radar, which was considered complicated and difficult with conventional equipment.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Fig. 2 is a block diagram showing an example of a conventional device, Fig. 3 is a block diagram showing an example of a pulse counting method,
FIG. 4 is a time chart showing data interpolation, FIG. 5 is a flow chart showing the interpolation procedure, and FIG. 6 is a block diagram showing another embodiment of the present invention.
DESCRIPTION OF SYMBOLS 10... Analog-digital converter, 12... Buffer circuit, 14... CPU, 18... Setting switch, 20... Processing table, 24... Scan converter, 34... Selector.

Claims (1)

[Scope of Claims] 1. In an orientation recognition method for obtaining orthogonal coordinate data in a single format in orthogonal coordinate display from orientation data in different formats in polar coordinate display, a format indicating means for indicating the format of the orientation data; At the time of data conversion, data interpolation means interpolates data according to the form of the azimuth data to obtain interpolated azimuth data; and the form instruction means uses the azimuth data and the interpolated azimuth data. 1. A direction recognition method, comprising: data conversion means for converting data in accordance with a form indicated by the data and obtaining the orthogonal coordinate data.