Transmitter for meteorological radar and transmission power adjustment method in transmitter for meteorological radar

Abstract

To provide a transmitter for a meteorological radar and a transmission power adjustment method in the transmitter for the meteorological radar, capable of keeping a transmission power level constant.SOLUTION: A transmitter 1 for a meteorological radar for receiving a pulse signal from a pulse generator 2, and amplifying and transmitting it, includes: a variable ATT 11 for attenuating the pulse signal; an FET device 12 for amplifying the pulse signal from the variable ATT 11; a peak power value detection part 14 for detecting a peak power value of the pulse signal output from the FET device 12 during pulse signal transmission, by referring to a gate signal which notifies of timing at which the pulse signal is transmitted from the pulse generator 2; and an adjustment part 15 for adjusting an attenuation amount by the variable ATT 11 so that a power value of the pulse signal output from the FET device 12 becomes a predetermined power reference value, based on the peak power value and the predetermined power reference value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a transmitter for a weather radar and a method for adjusting transmission power in a transmitter for a weather radar. [Background technology]

[0002] Weather radars perform observations by repeatedly transmitting pulse signals, reflecting them off of rain or snow, measuring the distance to the rain or snow from the time it takes for the reflected pulse to return, and measuring the amount of rain or snow from the amount of reflected pulses (Non-Patent Document 1). For this reason, weather radar transmitters are required to have a stable transmission power level (gain) over the long term.

[0003] However, the transmission power level of a transmitter usually varies slightly due to various external factors such as aging, temperature changes, and changes in PRF (pulse repetition frequency) and pulse width.

[0004] Figure 6 is a graph showing the relationship between the transmission power level and the pulse duty ratio (pulse width x PRF) in a conventional typical weather radar transmitter. As shown in Figure 6, this weather radar transmitter alternately transmits long and short pulse signals with different pulse duty ratios, so the transmission power level fluctuates by about 0.1 dB during one observation (5 minutes).

[0005] If no measures are taken to deal with such fluctuations in the transmission power level, the transmission power level will gradually decrease, which will eventually result in the weather radar being unable to make accurate measurements and the observation quality will deteriorate. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Japan Meteorological Agency, "Weather radar", [online], [Retrieved October 16, 2023], Internet<URL:https: / / www.jma.go.jp / jma / kishou / know / radar / kaisetsu.html> Summary of the Invention [Problem to be solved by the invention]

[0007] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a weather radar transmitter capable of maintaining a constant transmission power level and a method of adjusting transmission power in a weather radar transmitter. [Means for solving the problem]

[0008] In order to solve the above problem, the invention recited in claim 1 is a weather radar transmitter that receives a pulse signal from a pulse generator, amplifies the signal, and transmits it, comprising: an attenuator that attenuates the pulse signal; an amplifier that amplifies the pulse signal from the attenuator; peak power value detection means that refers to a gate signal that indicates the timing at which the pulse signal is transmitted from the pulse generator and detects a peak power value of the pulse signal output from the amplifier while the pulse signal is being transmitted; and adjustment means that adjusts an amount of attenuation by the attenuator based on the peak power value and a predetermined power reference value so that the power value of the pulse signal output from the amplifier becomes the predetermined power reference value.

[0009] The invention described in claim 2 is characterized in that, in the weather radar transmitter described in claim 1, it further comprises an average value calculation means for calculating an average value of the peak power value while the pulse signal is being transmitted, and the adjustment means adjusts the amount of attenuation based on the average value and the predetermined power reference value.

[0010] The invention described in claim 3 is a transmission power adjustment method for a weather radar transmitter that receives a pulse signal from a pulse generating device, amplifies the pulse signal, and transmits the amplifying signal, comprising: an attenuation step of attenuating the pulse signal; an amplification step of amplifying the pulse signal after the attenuation step; a peak power value detection step of detecting a peak power value of the pulse signal after the amplification step while the pulse signal is being transmitted, by referring to a gate signal that indicates a timing at which the pulse signal is transmitted from the pulse generating device; and an adjustment step of adjusting an amount of attenuation in the attenuation step based on the peak power value and a predetermined power reference value so that the power value of the pulse signal output from the amplification step becomes the predetermined power reference value. Effect of the Invention

[0011] According to the inventions described in claims 1 and 3, the weather radar transmitter is provided with an automatic control function for keeping the transmission power level constant, so that even if the transmission power level fluctuates due to an external factor, the transmission power level can be adjusted so as not to decrease accordingly, and the observation quality of the weather radar can be maintained. In addition, the transmission power is adjusted only while the pulse signal is being transmitted by referring to a gate signal that indicates the timing at which the pulse signal is transmitted from the pulse generator, so that no extra power is consumed and power saving is possible. In addition, since the peak power value is detected while the pulse signal is being transmitted, an accurate peak power value can be detected even in a weather radar equipped with a blanking function that does not radiate a pulse signal in only a specific direction, and the accuracy of the transmission power adjustment can be improved.

[0012] Furthermore, according to the invention as recited in claim 2, when adjusting the transmission power, the amount of attenuation by the attenuator is adjusted using the average value of the peak power value. This eliminates variation in the peak power value used, making it possible to adjust to a more accurate amount of attenuation, thereby improving the accuracy of the adjustment of the transmission power. [Brief description of the drawings]

[0013] [Figure 1]1 is a block diagram showing a schematic configuration of a weather radar transmitter according to a first embodiment of the present invention. [Diagram 2] FIG. 3 is a diagram for explaining detection of a peak power value in the weather radar transmitter according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a process diagram showing a procedure of transmission power adjustment performed in the weather radar transmitter according to the first embodiment of the present invention. [Figure 4] FIG. 11 is a block diagram showing a schematic configuration of a weather radar transmitter according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is a process diagram showing a procedure of transmission power adjustment performed in a weather radar transmitter according to a second embodiment of the present invention. [Figure 6] 1 is a graph showing the relationship between the transmission power level and the pulse duty ratio in a conventional weather radar transmitter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the present invention will be described based on the illustrated embodiment.

[0015] (Embodiment 1) 1 to 3 show a first embodiment of the present invention, and Fig. 1 is a block diagram showing a schematic configuration of a weather radar transmitter 1 according to the present embodiment. The weather radar transmitter 1 mainly includes a variable ATT (attenuator) 11, a FET device (amplifier) ​​12, a detection section 13, a peak power value detection section (peak power value detection means) 14, and an adjustment section (adjustment means) 15.

[0016] The variable ATT 11 and the FET device 12 are configured to output the pulse signal received from the pulse generator 2 toward a transmitting antenna (not shown).

[0017] The variable ATT 11 attenuates and outputs the pulse signal output from the pulse generator 2. The amount of attenuation in the variable ATT 11 is adjusted by the adjustment unit 15, which will be described later.

[0018] The FET device 12 amplifies the pulse signal attenuated by the variable ATT 11 and outputs it to the transmitting antenna. In order to save power, the FET device 12 is activated by applying a gate-source bias voltage only while the pulse signal is being transmitted. The FET device 12 receives the gate signal from the pulse generator 2 as the activation timing.

[0019] The detection unit 13, the peak power value detection unit 14 and the adjustment unit 15 are components for adjusting the transmission power of the weather radar transmitter 1. The adjustment of the transmission power is performed using a part of the pulse signal output from the FET device 12.

[0020] A part of the pulse signal output from the FET device 12 is detected by the detection section 13. The peak power value detection section 14 detects the peak power value of the detected pulse signal.

[0021] Fig. 2 is a diagram for explaining detection of peak power values ​​by the peak power value detector 14 in the weather radar transmitter 1 of this embodiment. As shown in Fig. 2, the weather radar transmitter 1 according to this embodiment alternately receives, at intervals, a short pulse (P0N) for short-distance observation and a long pulse (Q0N) for long-distance observation from the pulse generator 2, and also receives a gate signal that indicates the timing at which a pulse signal (short pulse or long pulse) is transmitted.

[0022] The correspondence between the pulse signal and the gate signal is as follows. The gate signal is transmitted at the same timing as the transmission of the pulse signal, and continues to be transmitted until the transmission of the pulse signal ends. When the gate signal is transmitted, it is said that the gate is open, and when the transmission of the gate signal ends, it is said that the gate is closed. In the following explanation, the section in which the gate is open (a, c in Figure 2) will be simply referred to as the "gate". The width of the gate (the time the gate is open) is proportional to the transmission time of the pulse signal, so the width a of the gate corresponding to the transmission of a short pulse is relatively short, and the width c of the gate corresponding to the transmission of a long pulse is relatively long. In addition, the time the gate is closed is proportional to the reception time of the pulse signal, so the width b of the section corresponding to the reception of a short pulse is relatively short, and the width d of the section corresponding to the reception of a long pulse is relatively long.

[0023] The peak power value detection unit 14 refers to this gate signal to grasp the timing at which the pulse signal is transmitted, measures the power value of the pulse signal output from the FET device 12 and detected by the detection unit 13 while the pulse signal is being transmitted (i.e., while the gate is open), and detects the peak power value, which is the highest power value within the gate, among the power values. The peak power value detected in this manner is regarded as representing the current transmission power of the weather radar transmitter 1.

[0024] Peak power detection unit 14 detects the peak power value while a long pulse is being transmitted (peak power value of a long pulse) separately from the peak power value while a short pulse is being transmitted (peak power value of a short pulse). This is because when adjusting the transmission power in adjustment unit 15, which will be described later, it is necessary to use the peak power value of a short pulse to adjust the transmission power of a short pulse, and to use the peak power value of a long pulse to adjust the transmission power of a long pulse. In the example shown in Fig. 2, the peak power value P of a long pulse is detected, but it is also possible to detect the peak power value of a short pulse.

[0025] The adjustment unit 15 has a function of adjusting the current transmission power of the weather radar transmitter 1, and first compares the peak power value corresponding to the current transmission power with a predetermined power reference value. Here, as the predetermined power reference value, a desired power value is set as the transmission power of the weather radar transmitter 1. Then, the peak power value of a short pulse needs to be compared with the predetermined power reference value for a short pulse, and the peak power value of a long pulse needs to be compared with the predetermined power reference value for a long pulse.

[0026] The adjustment unit 15 increases or decreases the amount of attenuation by the variable ATT 11 according to the result of the comparison, and adjusts the transmission power so that the power value output from the FET device 12, i.e., the transmission power value of the weather radar transmitter 1, always becomes the predetermined power reference value. Here, when the transmission power of the short pulse is adjusted by comparing the peak power value of the short pulse with the predetermined power reference value for the short pulse, the attenuation amount for the short pulse in the variable ATT 11 must be increased or decreased, and when the transmission power of the long pulse is adjusted by comparing the peak power value of the long pulse with the predetermined power reference value for the long pulse, the attenuation amount for the long pulse in the variable ATT 11 must be increased or decreased. In that case, it is necessary to distinguish between the transmission of the short pulse and the transmission of the long pulse. For example, since the period from the end of the transmission of the long pulse to the start of the transmission of the short pulse (d in FIG. 2) is relatively long, the time can be measured by a timer or the like, and the first gate signal after the time has passed is for notifying the timing of the transmission of the short pulse, and the second gate signal is for notifying the timing of the transmission of the long pulse.

[0027] To explain the adjustment of the transmission power in the adjustment unit 15 with a specific example, when the peak power value is 4.9 kW and the predetermined power reference value is 5 kW, the current transmission power of the weather radar transmitter 1 is 0.1 kW less than the predetermined power reference value, so the transmission power is adjusted by reducing the amount of attenuation by the variable ATT 11 so that the power value output from the FET device 12 becomes 5 kW. Note that, for convenience of explanation, no distinction is made between short pulses and long pulses here.

[0028] Next, the operation of the weather radar transmitter 1 in the above embodiment will be described with reference to the flowchart of FIG.

[0029] When the weather radar transmitter 1 receives a pulse signal from the pulse generator 2, it attenuates the pulse signal in the variable ATT 11 (step S1), amplifies the attenuated pulse signal in the FET device 12 (step S2), and outputs it to the transmitting antenna (step S3).

[0030] In parallel with the above steps, the weather radar transmitter 1 adjusts the transmission power. Specifically, the peak power value detection unit 14 refers to a gate signal that indicates the timing at which the pulse signal is transmitted, and detects the peak power value of the pulse signal output from the FET device 12 while the pulse signal is being transmitted (step S4), and the adjustment unit 15 adjusts the attenuation amount by the variable ATT 11 based on the peak power value and a predetermined power reference value so that the power value output from the FET device 12 becomes the predetermined power reference value (step S5).

[0031] As described above, the weather radar transmitter 1 according to the present embodiment has an automatic control function for keeping the transmission power level constant, so that even if the transmission power level fluctuates due to an external factor, the transmission power level can be adjusted so as not to fall accordingly, and the observation quality of the weather radar can be maintained. In addition, the transmission power is adjusted only while the pulse signal is being transmitted by referring to a gate signal that indicates the timing at which the pulse signal is transmitted from the pulse generator 2, so that no extra power is consumed and power saving is possible. In addition, since the peak power value is detected while the pulse signal is being transmitted, an accurate peak power value can be detected even in a weather radar equipped with a blanking function that does not radiate a pulse signal in only a specific direction, and the accuracy of the transmission power adjustment can be improved.

[0032] (Embodiment 2) Next, a weather radar transmitter 1 according to a second embodiment of the present invention will be described. Note that the same components as those in the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted.

[0033] Fig. 4 is a block diagram showing a schematic configuration of a weather radar transmitter 1 according to this embodiment. As shown in Fig. 4, the weather radar transmitter 1 according to this embodiment differs from the first embodiment in that it includes an average value calculation unit (average value calculation means) 16 that calculates an average value of peak power values ​​detected in a peak power value detection unit 14.

[0034] The average value calculation unit 16 calculates the average value of the peak power values ​​while the pulse signal is being transmitted. When short pulses and long pulses are alternately transmitted as the pulse signal as shown in Fig. 2, the short pulses and long pulses are also distinguished in calculating the average value, and the average value of the short pulses is calculated by averaging the peak power values ​​of multiple short pulses, or the average value of the long pulses is calculated by averaging the peak power values ​​of multiple long pulses.

[0035] Based on the calculated average value and a predetermined power reference value, adjustment unit 15 adjusts the amount of attenuation by variable ATT 11. Again, when the calculated average value is the average value of short pulses, it is compared with the power reference value for short pulses to increase or decrease the amount of attenuation for short pulses in variable ATT 11 to adjust the transmission power of the short pulses, and when the calculated average value is the average value of long pulses, it is compared with the power reference value for long pulses to increase or decrease the amount of attenuation for long pulses in variable ATT 11 to adjust the transmission power of the long pulses.

[0036] Next, the operation of the weather radar transmitter 1 in the above embodiment will be described with reference to the flowchart of FIG.

[0037] The weather radar transmitter 1 outputs the pulse signal received from the pulse generator 2 to the transmitting antenna in the procedure described in the first embodiment (steps S1 to S3), and adjusts the transmission power in parallel with this. As for the adjustment of the transmission power, after detecting a peak power value as in the first embodiment (step S4), in this embodiment, the average value calculation unit 16 calculates the average value of a plurality of peak power values ​​(step S6), and the adjustment unit 15 adjusts the attenuation amount by the variable ATT 11 based on the average value and a predetermined power reference value so that the power value output from the FET device 12 becomes the predetermined power reference value (step S5).

[0038] As described above, according to the weather radar transmitter 1 of this embodiment, when adjusting the transmission power, the attenuation amount by the variable ATT 11 is adjusted using the average value of the peak power value. This eliminates the variation in the peak power value used, and allows adjustment to a more accurate attenuation amount, thereby making it possible to improve the accuracy of the adjustment of the transmission power.

[0039] Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there are design changes and the like within the scope of the gist of the present invention, they are included in the present invention. [Explanation of symbols]

[0040] 1 Weather radar transmitter 11 Variable ATT (attenuator) 12 FET devices (amplifiers) 13 Detector 14 Peak power value detection unit (peak power value detection means) 15 Adjustment section (adjustment means) 16 Average value calculation unit (average value calculation means) 2. Pulse generator

Claims

1. A weather radar transmitter that receives a pulse signal from a pulse generator, amplifies the pulse signal, and transmits the pulse signal, an attenuator for attenuating the pulse signal; an amplifier for amplifying the pulse signal from the attenuator; a peak power value detection means for detecting a peak power value of the pulse signal output from the amplifier while the pulse signal is being transmitted, by referring to a gate signal that indicates a timing at which the pulse signal is transmitted from the pulse generator; an adjustment means for adjusting an amount of attenuation by the attenuator based on the peak power value and a predetermined power reference value so that the power value of the pulse signal output from the amplifier becomes the predetermined power reference value. A weather radar transmitter comprising:

2. an average value calculation means for calculating an average value of the peak power value during the transmission of the pulse signal; the adjusting means adjusts the amount of attenuation based on the average value and the predetermined power reference value.

2. A weather radar transmitter according to claim 1.

3. A method for adjusting transmission power in a weather radar transmitter that receives a pulse signal from a pulse generator, amplifies the pulse signal, and transmits the pulse signal, comprising the steps of: an attenuation step of attenuating the pulse signal; an amplifying step of amplifying the pulse signal after the attenuation step; a peak power value detection step of detecting a peak power value of the pulse signal after the amplification step while the pulse signal is being transmitted by referring to a gate signal that indicates a timing at which the pulse signal is transmitted from the pulse generating device; and an adjustment step of adjusting an amount of attenuation in the attenuation step based on the peak power value and a predetermined power reference value so that the power value of the pulse signal output from the amplification step becomes the predetermined power reference value. A transmission power adjustment method comprising:

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