JPS5858635B2 - radar couch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radar device suitable for a weather radar or the like, and particularly to a radar device that processes quantitatively averaged radar signals so as to be suitable for display.

Conventionally, in a radar device such as a weather radar that targets reflective objects with a wide area, as shown in FIG. In the case of weather radar, the power reflected by reflective objects such as rain and clouds in space is captured by the antenna 3, guided to the receiver 4 via the transmitter/receiver switch 2, where it undergoes frequency conversion and signal amplification. Furthermore, the logarithmically amplified and detected signal is detected by a logarithmic amplifier 5 and is supplied to a processing display device 7 via a low-pass filter 6.
Here, it is configured to perform processes such as iso-echo line generation and PPI display.

However, in the case of weather radar, such radar equipment does not require much quantitative accuracy regarding information such as rain intensity and rainfall amount, so emphasis has been placed on simply improving the image quality of PPI images. , quantitative averaging of radar received signals was not considered.

In other words, with conventional radar equipment, the amplitude information of the radar reflected waves obtained from the inherent properties of the target, such as rain, clouds, and snow, is not constant, so the image in the PPI image becomes unstable, resulting in a significant drop in image quality. become.

Therefore, in order to avoid this, we adopted a strategy of constructing the low-pass filter 6 shown in Figure 1 with a resistor R and a capacitor C, and adding this to the subsequent stage of the logarithmic amplifier 5 to utilize the integration effect of the time constant due to this RC. Was.

Incidentally, in this case, the time constant determined by RC is generally set to several times the transmission pulse width of the radar from the viewpoint of stabilizing image quality, so that a considerable tail is left in the time axis of the radar, that is, in the distance direction.

Therefore, the received signal of reflected waves from a reflecting object having a wide area such as a rain cloud is affected by this tail, and it is not possible to obtain a true averaging effect of the received signal.

Therefore, such a radar device is unsuitable for quantitative measurement, and in the past, no radar device has been found that can be processed to be suitable for display when quantitative averaging is performed.

The present invention has been made in view of the above points, and an object of the present invention is to provide a radar device that can process quantitatively averaged radar signals in a manner suitable for display.

An embodiment of the present invention will be described in detail below with reference to the drawings.

That is, in FIG. 2, the same components as in FIG. 1 are given the same numbers and the explanation is omitted.
- A quantitative averaging device 11 consisting of a D converter 8 and an azimuthal averaging circuit 10 is added after the logarithmic amplifier 5, and a buffer register 12 with feedback and a D- A (digital-analog) converter 13
A processing display device 15 consisting of a display device 14 and a display device 14 is added.

In the above, the quantitative averaging device 11 converts the output video signal obtained from the logarithmic amplifier 5 from an analog quantity to a digital quantity by sampling the amplitude at a predetermined time interval with the A-D converter 8, and calculates the azimuth direction average. The radar signal is quantitatively converted by calculating the average of a predetermined number of times in which the digital quantities are sequentially received in the azimuth direction in the conversion circuit 10.

The azimuth direction averaging circuit 10 calculates the total sum in the azimuth direction of data in the same distance category obtained from the received signals for consecutive M (M is an integer of 2 or more) transmission pulses, and calculates the average sum for each M transmission pulse repetition. This outputs averaged data in the same distance category.

Since the data obtained in the above manner is obtained by digitally averaging radar signals with quantitative precision in terms of azimuth, it can be directly applied to, for example, a PPI display and displayed. be able to.

However, if the averaged output in the azimuth direction from the quantitative averaging device 11 is simply added directly to the PPI display and displayed, the averaged output for the same distance segment will be the number of pulse hits, for example, M (M is 2 or more). (a positive integer), the display is actually swept only once during M sweeps, which degrades the quality of the display and is not practical for PPI graphics.

Therefore, the present invention provides the quantitative averaging device 11 as described above.
A buffer register 12 with feedback and D-A are further provided at the subsequent stage.
The present invention is characterized in that a processing display device 15 is added to the display device 14, such as a PPI display device, via a converter 13, so that the display can be displayed without deteriorating the quality of the display.

That is, the average output from the azimuth direction averaging circuit 10 is supplied to a buffer register 12 (for example, a shift register) having a predetermined number of bits corresponding to the number of distance divisions, and is temporarily stored therein.

Thereafter, the stored contents of the buffer register 12 are synchronized with the operation of the azimuth direction averaging circuit 10 and are shifted one bit at a time in the distance direction, that is, the data arranged in the order of the distance direction is shifted in order, and the data for each distance division is sequentially D. -A converter 13.

As a result, data in the distance direction is output from the buffer register 12 one after another in the order of distance, and the display device 14 can display data for one sweep period.

However, if this continues, the buffer register 12 will become 1.
If the data for the sweep is output, there will be no stored data, so the display device 14 cannot display data continuously for M sweep periods.

Therefore, at the same time as the data stored in the buffer register 12 is output, the data is fed back to the input of the buffer register 12 again to circulate the stored contents.

As a result, the averaged video converted from a digital quantity to an analog quantity is outputted one after another from the D-A converter 13 even after one sweep period, so that the display device 14 displays data one after another even after one sweep period. becomes possible.

Therefore, by repeating the above processing in correspondence with the quantitative averaging number M, that is, by making the same data circulate through the buffer register 12 M times, during the M sweep period of the current signal averaging period, , it becomes possible to display for each sweep the signal average data of the same distance section, which has already been signal averaged over the past M times.

FIG. 3 shows an example of such a display. In this case, the azimuth direction is divided into n equal parts clockwise, the distance direction is divided into four equal parts in the radial direction, and the numbers 2 to 6 in the figure indicate the specific azimuth direction and This shows the average value in a specific distance direction.

On the other hand, after repeating M times, all of the data for one sweep period in the buffer register 12 is updated to new data averaged over M times of signals, and from this point on, this new data is displayed at the next averaging period timing. It will be displayed every time depending on the .

Therefore, according to the present invention as described above, although the radar signal is quantitatively averaged, the display is also done in accordance with the display timing, so that the output with true signal averaging effect can be obtained. Stable, high-quality images can be displayed without deteriorating display quality.

Note that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the gist of the present invention.

For example, in the embodiment described above, a PPI display device is used as the display device, but other display devices may be used.

Furthermore, in the above embodiment, the case where an azimuth direction averaging circuit is used as the quantitative averaging device has been described, but a distance direction averaging circuit may be added as necessary before or after the azimuth direction averaging circuit. Good too.

Further, in the above embodiment, a case has been described in which a logarithmic amplifier is used to amplify the radar reception signal, but this logarithmic amplifier is not necessarily required to achieve the object of the present invention.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing a conventional radar device, FIG. 2 is a configuration explanatory diagram showing an embodiment of the radar device of the present invention, and FIG. 3 is a diagram showing an example of the display of the radar device according to the present invention. be. 1...Transmitter, 2...Transmit/receive switch, 3
...Antenna, 4...Receiver, 5...
...logarithmic amplifier, 8...A-reverse converter, 10
...Azimuth direction averaging circuit, 11...Quantitative averaging device, 12...Buffer register,
13...D-A converter, 14...Display device, 15...Processing display device.

Claims (1)

[Claims] 1 In a radar device that receives reflected waves from reflective objects that exist over a wide area of space, such as rain and clouds, and performs signal processing to display weather data, analog amplitude information of the radar reception signal caused by the reflected waves is digitally transmitted. A means for converting into a signal, and addition of quantitative data in the same distance category in the azimuth direction among the data obtained from the received signal for continuous M (M is an integer of 2 or more) transmitted pulses to which the output signal of this means is supplied. an averaging means for averaging quantitative data regarding reflective objects existing over the wide area by calculating an average, and outputting an averaged digital signal every M transmission pulse repetitions; and an output signal of the averaging means. is supplied, and only the averaged data as many as the number of distance divisions are arranged and stored in the order of the distance direction, and by sequentially shifting the stored data in the distance direction and returning the read data to the input terminal, data for each adjacent distance division can be calculated. The data of the same distance division is read out in synchronization with the sweep repetition of the display means, which will be described later, and all of the stored data is updated to the latest averaged data every M transmission pulse repetitions. a converter for converting the digital signal read by the storage means into an analog signal; and a converter for converting the digital signal read by the storage means into an analog signal; and a display means for displaying each sweep repetition.