JPS62161071A - Apparatus for processing radar information - Google Patents

Abstract

PURPOSE:To rapidly obtain accurate data relating to rainfall amount by providing a first gate means, a memory, an integrating means and a second gate means, etc. CONSTITUTION:A data processing circuit 30 is constituted of a first gate circuit 31, an adder 32, a correction value memory 33, an integrator 34 and a second gate circuit 35 etc. The circuit 31 provides a threshold value of a predetermined level to radar video data RVD to remove a noise component. At the same time, the circuit 31 outputs an enable signal EN to the circuit 35 corresponding to the passing time of effective data exceeding the threshold value. The adder 32 adds the output of the circuit 35 to the output (radar video data RVD') of the circuit 31 on the basis of the sampling timing ST of a sampling signal. Next, the added value is outputted to a radar indicator as rainfall amount data RD at any time. Further, the integrator 34 cumulates and adds the value read from the memory 33 on the basis of the sampling timing ST. The circuit 35 receives the cumulated value of the integrator 34 to permit the passage thereof during a time when the signal EN added from the circuit 31 is a 1 level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The radar information processing device according to the present invention is a processing device particularly suitable for use in a weather radar to obtain data regarding rainfall accurately and easily.

[Conventional technology]

To measure the amount of rainfall using the above-mentioned weather radar, the radar radio waves (generally pulse modulated) irradiated to the target rain clouds and their rainfall are received, and the reflected radio waves from these rain clouds and rainfall are received. It is well known to measure the amount of rainfall based on the power intensity of radio waves. FIGS. 4 and 5 show a conventional general configuration of a radar information processing apparatus that processes such received radio waves to measure rainfall.

FIG. 4 shows the general configuration of a so-called small-scale system that is mounted on, for example, an aircraft and measures the appearance of rain clouds and the amount of rainfall. As shown in the figure, this system is broadly composed of a receiver 10 that demodulates the received radio waves, and a radar indicator 20 that displays this demodulated signal through a cathode ray tube or the like, and usually displays the shape of the rain cloud in question. It has become possible to measure rainfall amounts in real time.

FIG. 5 shows the general configuration of a so-called large-scale system that is mounted, for example, on the ground or on a ship to measure the appearance of rain clouds and the amount of rainfall.

In this system, as shown in the figure, after a demodulated signal from a receiver IO is converted into a digital signal by an A/D converter 11, a computer 12 performs necessary processing such as adding various corrections to the digital signal. It is normal that the state of the rain clouds and the amount of rainfall can be displayed on the total radar indicator 20 as more accurate information.

[Problem that the invention seeks to solve]

Assuming that there is no attenuation due to rain between the rain and the radar device (hereinafter referred to as rain on the way), the received power of the reflected radio waves due to the rain is as shown by the line R1 in Figure 3. The attenuation occurs in approximately direct proportion to the relative distance between the radar IT and the radar IT, but normally, in addition to the attenuation that accompanies the wavelength of the relative distance, the attenuation due to the above-mentioned rain along the way also acts to a non-negligible extent. , in fact, the third
Attenuation becomes greater in the manner shown by line R2 in the figure. For example, in the X band, the attenuation fL due to rain on the way (not including the attenuation due to the above-mentioned relative separation) is 1.3 L#2x0.007xRx r (dB) = (1
) However, it is known that R = amount of rainfall on the way (m) r: relative distance between the target rainfall and the radar device (Km).

However, considering the conventional radar information processing devices mentioned above, for example, the small-scale system shown in FIG. , as well as accurate rainfall amounts.

It was also difficult to obtain accurate information about the appearance of rain clouds (for example, rain clouds behind large rain clouds appear smaller than they actually are on the indicator), and the large-scale system shown in Figure 5 also Now, although it is possible to obtain accurate information regarding the amount of rainfall, etc. by using the computer 12 to correct power attenuation due to rainfall during the process and other various factors using software, the computer 12 itself Obtaining such information in real time has been difficult due to issues such as computational speed. Of course, if a computer 12 capable of high-speed calculations is used, real-time processing of the same information becomes possible, but this would not only make the system large-scale but also expensive, making it impractical.

As described above, in the past, it has not been possible to easily obtain accurate data regarding rainfall in real time.

[Means and effects for solving the problem] In the present invention, the above-mentioned received radio waves are sampled at predetermined distance intervals with respect to the relative distance between the radar device and the target rainfall, and are converted into digital signals. A first gate that sets a predetermined threshold for the sampled received radio waves, removes noise components contained therein, and outputs an appropriate enable signal in response to the transit time of the effective radio waves exceeding the threshold. means, a memory storing a plurality of values indicating the amount of power attenuation over a predetermined distance corresponding to the sampling interval of the received radio wave in a table shape corresponding to each power value of the received radio wave, and the above-mentioned power read from the memory. an integrating means for accumulating (for example, cumulatively adding) a value indicative of the amount of attenuation based on the sampling timing; and receiving the accumulated value of the integrating means, and outputting the enable signal from the first gate means. The second
gate means, and replenishment for replenishing (for example, adding) the cumulative value that has passed through the second gate means of the integrating means to the sample received radio wave that has passed through the first gate means, based on the timing of the sampling. A hardware circulation circuit is constituted by the replenishing means, and the replenishment results from the replenishment means are outputted as data indicating the amount of rainfall in question, and the memory is sequentially accessed based on the replenishment results at any time.

As a result, even if the sample power intensity of the received radio wave is attenuated at each distance corresponding to the sampling interval, the intensity is replenished by the amount corresponding to the amount of attenuation each time. Even if the noise is mixed in, the influence of the noise on the rainfall amount data and the cumulative value of the integration means can be effectively avoided. Therefore, the values obtained as rainfall data will be maintained at accurate values corresponding to the actual rainfall in the target area.

〔Effect of the invention〕

As described above, according to the radar information processing apparatus according to the present invention, accurate data regarding rainfall amount can be quickly obtained in real time by simply providing a simple hardware circuit.

This processing device can be used in both the small-scale system and the large-scale system mentioned above, but the device itself can be made very small and lightweight, and the change in the relative distance between the radar device and the target rainfall is important. Considering the fact that it can quickly follow even when the speed is high, it can be said that it is more suitable to be adopted in a small-scale system mounted on an aircraft.

〔Example〕

FIG. 1 shows an embodiment of a radar information processing device according to the present invention.

In this embodiment device, in addition to the demodulation function described above, the receiver 10 also has a function of logarithmically (LOG) compressing the demodulated signal, and a function of compressing the received 11E power due to the relative distance between the radar device and the target rain. It is assumed that a function for correcting attenuation (a well-known function in general radar equipment) is also provided. Therefore, the radar video signal RVS output from the receiver 10 has a LOG characteristic with respect to the received power and is a signal subjected to distance attenuation correction.

This signal vS is converted from analog to digital by the A/D converter 11 based on the sample timing ST of the sampling signal, which is emitted every time the relative distance between the radar device and the target rainfall changes by a predetermined distance. It is added to the data processing circuit 30 as video data RVD.

As shown in FIG. 1, the data processing circuit 30 is composed of a circulation circuit including a first gate circuit 31, an adder 32, a correction value memory 33, an integrator 34, and a second gate circuit 35. Among these, the first gate circuit 31 receives the analog/digital converted radar video data R.
A threshold of a predetermined level is set for VD to remove the noise component normally included, and in response to the passage time of valid data exceeding the threshold, for example, "1" is set at the logic level.
The enable signal BN at level 2 is sent to the second gate circuit 3.
5, and the adder 32 outputs the first signal based on the sample timing ST of the sampling signal.
Output of gate circuit 31 (radar video data RVD'
) is added to the output of the second gate circuit 35, and this is outputted to a radar indicator, etc. (not shown) as rainfall amount data RD at any time. A plurality of values indicating the amount of power attenuation over a predetermined distance (which can be calculated as appropriate based on the formula 0), etc.) are stored in advance in a table shape corresponding to each power value of the same received radio wave. Based on the sample timing 8T of the sampling signal, the addition output (rainfall amount data RD) of the adder 32 is used as address data, and a stored value corresponding to the indicated power value (a value indicating the amount of power attenuation - this becomes the correction value) ), and the integrator 34 cumulatively adds the value (the correction value) read from the memory 33 based on the sample timing ST of the sampling signal,
The second gate circuit 35 receives the accumulated value of the integrator 34, and while the enable signal EN applied from the gate circuit 31 of @1 is at the logic level "1" on the same side. This is what allows it to pass. Please refer to Figure 2 below for this data processing time! ! The operation of 630 will be explained in detail.

Here, the device of this embodiment is employed in a small-scale system mounted on an aircraft, etc., and the relative distance r between the radar device and the rainfall to be measured changes approximately in proportion to time (for example, as the distance increases, become).

Further, in this example, as shown in FIG. 2, a case is shown in which the same amount of rainfall is measured intermittently over a relatively wide range.

Now, in this embodiment device, under these conditions, the receiver 1
The demodulated signal (radar video signal) 1 (, V8) is sampled, subjected to analog/digital conversion, and taken into the data processing circuit 30.

That is, the distance change timing by each predetermined distance Δr becomes the sample timing ST of the above-mentioned sampling signal in the same embodiment device. Radar video data R sampled and analog/digital converted
VD corresponds to the predetermined distance Δr and is input to the data processing circuit 30 as a digital signal indicating the level content shown in FIG. 2 (→) in correspondence with the rain area.

Management, this radar video data RVD is shown in Figure 2 (
A noise component as shown in a) is also included.

The first gate circuit 31 of the data processing circuit 30 is a gate circuit that removes a loud noise component from the radar video data RVD and adds only its effective component to the adder 32 at the next stage. 2. Set the B level as shown in Fig. 2 (a) (this setting can be done as appropriate based on the empirically known noise level) and remove signal components (noise components) below this level, Figure 2 υ
) is output to the adder 32. Further, in parallel with this, in the first gate circuit 31, the logic level becomes 111 as shown in FIG. 2(C), that is, in synchronization with the transit time (existence time) of the radar video data RVD' Enable signal EN that is at logic @O” level at other times
is output to the second gate circuit 35. Note that the level difference at each sampling point of the radar video data RVD' is determined by the attenuation amount L(
3 and equation (1)), and the level difference corresponding to this attenuation -iL is equal to (dL) corresponding to the time interval t of the sample timing ST.
/di). For example, if 1゜3, in the X band (d (2x0.007xk xr
)/dt).

On the other hand, in the correction value memory 33, attenuation values (dL/dt) corresponding to these sampling intervals are stored as correction values for each power value of received radio waves (radar video data RVD').
A plurality of values are stored in advance in the form of a table corresponding to each digital value (indicated by ). These correction values are read out at any time by using the output data of the adder 32 as address data and corresponding to the contents thereof. These read correction values (dL/dt) are sequentially cumulatively added to the integrator 34 in the manner shown in FIG. Figure 2 (e
).

Therefore, along with the above-mentioned sampling, radar video data RVD' as shown in FIG. 2(b)/)
is obtained, the radar video data RVD of the
/ and the integral value of the integrator 34 at that point Σ=/(dL/d
t)d t=Σ', that is, Fig. 2(d) and (e
) The value shown in ■ is "0" (at this point, the correction value memory 33
No value is read from adder 3.
2, and the data indicating the value shown in ■ in FIG. and the corresponding correction value (d
L/d t ) is read from the memory 33. This read value is transferred to the integrator 3 at the next sample timing.
4, and this cumulative addition value (the value marked with ■ in Fig. 2 (d) and (e)) is the radar video data R at that time.
VD/ and is added in the adder 32.

That is, if radar video data RVD' as shown in ■ in FIG. 2(b) is obtained by the second sampling, the radar video data RVD/ in FIG. The cumulative addition value shown in (2) is added by the adder 32. This addition value becomes the value shown in (2) in Figure 2 (0), and the data showing this value is the rainfall amount by the second sampling. The data is output as data RD from the data processing circuit 30. The same processing as described above is repeated for the third and subsequent samplings.

However, in this example, for example, corresponding to the 4th to 10th samplings, the radar video data RVI)/ is maintained at the "0" level as shown in FIG. 2(b). , Correspondingly, the logic level of the enable signal EN becomes 10'' level (inactive level) as shown in FIG. 2(C), so that the correction value read from the correction value memory 33 during this time (aL/dt) is “0
” (or no value is read out (state)), and therefore the cumulative value of the integrator 34 is also accumulated corresponding to the previous third sampling as shown in FIG. 2(d). However, since the second gate circuit 35 prohibits the accumulated value from passing as shown in FIG. 2(e), the output of the adder 32, that is, the amount of rainfall During this period, the data RD is also maintained at "0" as shown in FIG. 2 (0).

Even if the radar video data RVD contains noise components as shown in FIG. 2(a), the above correction amount Σ(
This means that it is possible to increase the correction amount Σ(Σ') to a maximum of (maximum output value of adder 32) - (threshold B level), which in turn expands the dynamic range of the correction amount Σ(Σ') and This means that rainfall measurements can be made with very high precision. Then, in response to the eleventh sampling, the same process as in the previous first sampling is started again, and thereafter, the correction amount Σ(Σ') is replenished in the same manner.

In this way, according to this embodiment device, even if the power intensity of the received radio waves is attenuated due to rain, the power can be adjusted in real time and over a wide dynamic range at any time according to the relative distance between the radar location and the target rain. The attenuation of the sleeve can be reduced.

In the above example, the case where the device of this embodiment is adopted in a small-scale system is shown, but it goes without saying that the device of this embodiment can be similarly adopted in a large-scale system placed on a ship or on the ground. Incidentally, in this case, the relative distance between the above-mentioned radar device and the target rainfall changes due to the movement of the rain cloud itself, etc. Also, on the same side, for convenience, the relative distance between the above-mentioned radar device and the target rainfall changes over time. Although we have explained the operation on the assumption that the relative distance increases with the passage of time, Figure 2 shows how each data changes as a function of the relative distance, and conversely, the same relative distance increases over time. Even if the radar equipment approaches the target rainfall and then moves away from it, etc., it is actually effective based on the relationship shown in Figure 2. data can be processed.

Of course, in this case, under the condition that the relative distance is gradually reduced, a value having a negative sign is used as the correction value (aL/dt).

Further, in the above-described embodiment, the receiver 10 already has the function of logarithmically compressing the demodulated signal and the function of performing distance correction, but it is of course possible to provide these functions to the data processing circuit 30. . For example, if the radar video signal RVS output from the receiver 10 has linear characteristics with respect to received power, a multiplier is used in place of the adder 32 as the power value replenishment means, and The integrator 34 can be logarithmically compressed by replacing the above-mentioned addition type with a multiplication type, and as the data stored in the correction value memory 33 in advance, the data shown on the line R1 in FIG. Distance correction can also be performed at the same time by using a method that also takes into account received power attenuation due to the relative distance between the radar device and the target rainfall. However, the logarithmic compression itself may be performed at a later stage of the data processing circuit 30. However, in this case, the correction value stored in advance in the correction value memory 33 is also set and registered as a value corresponding to the amount of attenuation based on the linear characteristic.

In addition, in the same embodiment device, a first gate circuit 31 is provided between the A/D converter 11 and the adder 32, and the above-mentioned noise based on an appropriate threshold is added to the analog/digital converted radar video data VD. Although component removal processing is performed, another example is to provide an analog circuit corresponding to the first gate circuit between the receiver 10 and the A/D converter 11,
Of course, the radar video signal RVS, which is an analog signal, may be subjected to similar processing in an analog manner. The enable signal EN may have any form as long as it can open and close the second gate circuit 35 in the manner described above.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a radar information processing device according to the present invention, FIG. 2 is a diagram showing an example of the operation of the device, and FIG. 4 and 5 are block diagrams showing configuration examples of conventional radar information processing devices, respectively. 10...Receiver, 11..., A/D converter, 3o...
・Data processing circuit, 31...first gate circuit, 32・
... Adder, 33... Correction value memory, 34... Integrator, 35... Second gate circuit. ...'Representative Patent Attorney Takahisa Kimura ;,,11j・2

Claims (1)

[Claims] Receiving radio waves reflected by the rain clouds and rainfall of radar radio waves irradiated to the rain clouds and the rainfall,
A radar information processing device that samples the received radio waves at predetermined distances with respect to the relative distance between the radar device and these rain clouds and rainfall, and forms digital rainfall amount data corresponding to the power intensity, a first gate means that sets a predetermined threshold value to remove noise components contained therein, and outputs an appropriate enable signal in response to the passage time of the effective radio wave exceeding the threshold; a memory storing a plurality of values indicating the amount of power attenuation over a predetermined distance corresponding to the sampling interval in a table shape corresponding to each power value of the received radio wave; and a value indicating the amount of power attenuation read from the memory. an integrating means that accumulates based on the timing of the sampling; a second gate means that receives the accumulated value of the integrating means and allows it to pass while the enable signal is output from the first gate means; replenishment means for replenishing the power value of the received radio waves that have passed through the first gate means with the cumulative value that has passed through the second gate means of the integration means, based on the timing of the sampling; A radar information processing device that outputs the results of replenishment at any time by the replenishment means as the rainfall amount data, and accesses the memory based on the results of the replenishment at any time.