JPH07325143A - Radar video transmission system - Google Patents

Abstract

PURPOSE:To realize remote transmission of an azimuth signal, e.g. an ARP (azimuth reference pulse) or an ACP (azimuth minimum variation pulse), on a same remote transmission line as the video signal and to realize a high quality radar image composition using a normal quality transmission line as the remote transmission line. CONSTITUTION:A trigger signal and an ARP are encoded and an ACP is subjected to frequency division by (n) at a transmission interface 16. The trigger signal, the ARP, the ACP and a monitor signal are synthesized through a synthesis circuit 22 into a video signal. The composite video signal thus produced is transmitted on a single remote transmission line 28 to a receiving interface 18. The receiving interface 18 separates other signals from the video signal and decodes the trigger signal and the ARP. PLLs 34, 36 are phase locked with the trigger signal and the ARP. A multiply by (n) circuit 42 multiplies the separated ACP by (n) to recover the original period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar video transmission method for remotely transmitting a video signal obtained by a radar device.

[0002]

2. Description of the Related Art A radar device has been conventionally known as a device for searching for the presence of a target in the surroundings and its position (distance, direction). As the radar device, for example,
There is a configuration in which a radio signal is transmitted while rotating the antenna and the reflected wave is received to generate a radar image. In such a configuration, when a wireless signal is transmitted, a radar image of the antenna azimuth at that time is obtained, and when the antenna makes one rotation, a radar image of all azimuths is obtained. One transmission of a radio signal is called a sweep, and a cycle in which the antenna makes one rotation is called a scan.

The radar image obtained by such transmission / reception, to be exact, a video signal indicating the radar image is a signal in polar coordinate format. That is, when focusing on a certain sweep, the video signal of that sweep represents a radar image of the antenna direction at the time of transmission / reception, and the time from transmission to reception represents the distance to the target. On the other hand, as a device for displaying radar images, a raster scan type display device such as a CRT is generally used. Since this type of display device is basically a display device of a rectangular coordinate format, it is necessary to convert a video signal from a polar coordinate format to a rectangular coordinate format in order to display a radar image on its screen. In order to perform this coordinate conversion, it is necessary to know the transmission timing and the antenna azimuth. The former is obtained by the trigger signal and the latter by the azimuth signal.

Therefore, when the video signal is transmitted in the state before the coordinate conversion and the radar image is displayed on the display device at a remote place, not only the video signal but also the trigger signal and the direction signal are transmitted. There is a need to. FIG. 4 shows an example configuration of a system for performing such remote transmission.

In the system shown in this figure, the video signal obtained by the radar device 10 is remotely transmitted to the display device 14 together with other signals through the remote multiplex transmission line 12 such as a wireless transmission line and an optical transmission line. . At that time, the transmission interface 16 provided on the radar device 10 side synthesizes the trigger signal and the monitor signal with the video signal, and the reception interface 18 provided on the display device 14 side synthesizes the composite video signal (the trigger signal and the monitor signal are synthesized. The generated video signal: the trigger signal and the monitor signal are separated from the video signal (see FIG. 5A). That is, the transmission interface 16 encodes the trigger signal by the coder 20 and then synthesizes the trigger signal and the monitor signal into the video signal by the synthesis circuit 22, and the reception interface 18 triggers from the video signal by the separation circuit 24. The signal and the monitor signal are separated, and the decoder 26 decodes the trigger signal. The monitor signal is a signal for carrying the status of the radar device 10 and various messages.

The direction signals ARP and ACP are transmitted on a channel different from that of the composite video signal.
Here, ARP is the azimuth reference pulse, and ACP is the azimuth minimum change pulse. That is, ARP is a pulse generated when the antenna faces a certain reference azimuth, and ACP is a pulse generated when the antenna azimuth changes by a very small unit. Therefore, a predetermined number of A
CP occurs. In order to accurately form a radar image on the display device 14 side, in addition to the trigger signal, these ARP
And ACP must be reproducible. Also, in general,
The ACP cycle is shorter than the repetition cycle of the trigger signal as shown in FIG.

[0007]

When transmitting a video signal in such a format, a multiplex transmission line must be used as a remote transmission line, which increases the transmission cost. That is, in addition to the video signal transmission line, a line such as a voice band transmission line must be used for transmitting the azimuth signal. Further, when a microwave multiplex line is used as a multiplex transmission line, it is difficult to maintain the line quality under normal specifications, so the line margin must be increased.

The present invention has been made to solve the above problems, and it is possible to stably transmit a video signal, a trigger signal, an azimuth signal, etc. by only one transmission line having a normal quality. The purpose is to

[0009]

In order to achieve such an object, a radar video transfer method according to the present invention compares an azimuth change signal indicating a change in antenna azimuth in a radar device with a repetition period of a video signal. It is characterized in that the frequency is divided to have a sufficiently long cycle, and then remote transmission is performed using the same remote transmission path as that of the video signal, and the remotely transmitted azimuth change signal is multiplied and returned to the cycle before division.

The radar video transmission method according to the present invention further encodes the trigger signal indicating the transmission timing in the radar device and the azimuth reference signal indicating the reference of the antenna azimuth in the radar device, and encodes the same signal as the video signal. The remote transmission path is used to decode the trigger signal and the azimuth reference signal transmitted remotely.

The present invention is characterized in that it is phase-synchronized with the azimuth change signal, the trigger signal and the azimuth reference signal transmitted remotely.

[0012]

In the present invention, the azimuth change signal is frequency-divided so that it has a period sufficiently longer than the repetition period of the video signal, and is transmitted remotely using the same remote transmission path as that of the video signal. The azimuth change signal transmitted by remote control is multiplied so as to have a period before frequency division. Therefore, in the present invention, although the same remote transmission line as the video signal is used for transmission, the direction change signal can be transmitted with high quality, and the remote transmission line 1 having normal quality can be obtained. Suitable transmission can be performed only by using the channel.

Further, in the present invention, in addition to the azimuth change signal, the trigger signal and the azimuth reference signal are also remotely transmitted through the same remote transmission path as the video signal. At this time, the trigger signal and the azimuth reference signal are encoded / combined. Therefore, in the present invention, all the signals necessary for displaying the radar image are remotely transmitted using the single remote transmission path.

In the present invention, the phase synchronization with the azimuth change signal, the trigger signal and the azimuth reference signal transmitted remotely is ensured. Therefore, even if the azimuth change signal, trigger signal and azimuth reference signal are missing on the remote transmission line due to noise, disturbance, etc. Since it is possible to make up for it, the quality becomes high when a radar image is constructed on the receiving side.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. It should be noted that the same or corresponding configurations as those of the conventional example shown in FIGS. 4 and 5 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows the configuration of a system according to an embodiment of the present invention. In this embodiment, the radar device 10 and the display device 14 include a transmission interface 16
And a single remote transmission line 28 via the receiving interface 18. As the remote transmission line 28, for example, a wireless transmission line, an optical transmission line, or the like can be used.

The transmission interface 16 includes a coder 20,
In addition to the synthesizing circuit 22, the coder 30 and the n frequency dividing circuit 32 are included. The coder 30 is a circuit that encodes ARP, and the n-divider circuit is a circuit that divides ACP by n. The combining circuit 22 combines the encoded trigger signal, the video signal and the monitor signal, as well as the encoded ARP and the n-divided ACP, and sends them to the remote transmission line 28. The reception interface 18 has PLL circuits 34 and 36, a sweep memory 38, a decoder 40, and an n multiplication circuit 42 in addition to the separation circuit 24 and the decoder 26. The separation circuit 24 separates the trigger signal, ARP, ACP, and monitor signal from the video signal received via the remote transmission path 28. The decoder 26 decodes the trigger signal and the PLL 34 is phase-locked with the decoded trigger signal. The video signal separated by the separation circuit 24 is stored in the sweep memory 38 for one sweep. The decoder 40 uses the ARP separated by the separation circuit 24.
, And the PLL 36 is phase locked to the output of the decoder 40. The n multiplication circuit 42 multiplies the separated ACP by n,
Return to the same cycle as ACP before dividing by n. Display device 14
Is the trigger signal, the video signal,
A radar image is displayed on the screen based on the ARP, ACP and monitor signals.

As described above, in this embodiment, in addition to the trigger signal, the video signal and the monitor signal, the ACP and A
The composite video signal (see FIG. 2) in which the RP is further combined is transmitted through the single remote transmission line 28. This kind of transmission is possible because n
This is because the frequency is divided and n is multiplied after separation. That is, the ACP is frequency-divided so as to have a cycle sufficiently longer than the repetition cycle of the trigger signal, that is, the repetition cycle of the video signal, and is divided and transmitted to the remote transmission line 28. Since the n-multiplier circuit 42 of the reception interface 18 multiplies this by n and reproduces the ACP before frequency division by n, even though the remote transmission line 28 common to the video signal is used,
Since P is transmitted with high quality, the radar image can be accurately reproduced on the display device 14 side.

The n multiplication circuit 42 can be realized, for example, as a configuration shown in FIG. That is, the ACP separated by the separation circuit 24 is first input to the phase detector 44. The phase detector 44 includes an n frequency dividing circuit 50.
ACP is phase-detected using the output of the VCO, the signal obtained as a result is smoothed by the loop filter 46, and then the VCO is
48. The VCO 48 converts the voltage of the signal supplied from the phase detector 44 via the loop filter 46 into a frequency, and outputs this as ACP. Also, VC
The output of O48 is supplied to the n frequency dividing circuit 50, and supplies the reference phase when the phase detector 44 performs the phase detection.
With such a configuration, even if the ACP is lost on the remote transmission line 28, the ACP with the missing supplemented is reproduced on the display device 14 side, which causes a momentary interruption or disturbance. It becomes a strong device.

The PLLs 34 and 36 provided on the output sides of the decoders 26 and 40 are circuits for compensating for the loss of the trigger signal or ARP decoded by the decoder 26 or 40. That is, the PLLs 34 and 36
Since the phase synchronization of the trigger signal and ARP is ensured by the above, even if the trigger signal or ARP is lost due to noise or the like on the remote transmission line 28, these signals are supplemented to realize an accurate radar image device. can do.

As described above, according to the present embodiment, high-quality radar is achieved by using the remote transmission line 28 having normal quality by the transmission by the ACP frequency division / multiplication and the phase synchronization using the PLL. Video display can be realized.

[0022]

As described above, according to the present invention,
Since the azimuth change signal is frequency-divided so that it has a period sufficiently longer than the repetition period of the video signal, it is transmitted remotely using the same remote transmission line as the video signal. It becomes possible to transmit the direction change signal.

Further, according to the present invention, in addition to the video signal and the trigger signal, the azimuth change signal and the azimuth reference signal are remotely transmitted through the same remote transmission path, so that various signals necessary for the construction of the radar image are transmitted. Since the remote transmission is performed by a single remote transmission line, a system with low line cost can be obtained.

Furthermore, by ensuring phase synchronization by using a PLL circuit or the like on the receiving side, it is possible to realize a high quality radar image structure using a remote transmission line of normal quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a signal in this embodiment.

FIG. 3 is a block diagram showing a configuration of an n multiplication circuit.

FIG. 4 is a diagram showing a configuration of a system according to a conventional example.

FIG. 5 is a diagram showing a signal configuration in this conventional example.

[Explanation of symbols]

 10 radar device 14 display device 16 transmission interface 18 reception interface 20, 30 coder 22 synthesis circuit 24 separation circuit 26, 40 decoder 28 remote transmission line 32 n frequency division circuit 34, 36 PLL 38 sweep memory 42 n multiplication circuit ARP azimuth reference pulse ACP minimum change pulse

Claims (3)

[Claims] 1. A radar video transmission method for remotely transmitting a video signal representing a radar image obtained by a radar device, wherein a direction change signal indicating a change in antenna direction in the radar device has a cycle sufficiently longer than a repetition cycle of the video signal. The radar video transmission method is characterized in that the frequency division is performed so that it is remote-transmitted using the same remote transmission path as the video signal, and the remote-transmitted direction change signal is multiplied and returned to the period before the frequency division. . 2. The radar video transmission method according to claim 1, wherein a trigger signal indicating a transmission timing in the radar device and an azimuth reference signal indicating a reference of an antenna azimuth in the radar device are encoded and are the same as the video signal. A radar video transmission method characterized by performing remote transmission using a remote transmission path and decoding the remotely transmitted trigger signal and azimuth reference signal. 3. The radar video transmission method according to claim 2, wherein the phase synchronization is carried out with respect to the azimuth change signal, the trigger signal and the azimuth reference signal transmitted by remote control.