JP2012052923A - Weather radar device and weather observation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure that three-dimensional weather data can be surely collected with high resolution in terms of both time and space.SOLUTION: The weather radar device includes: a phased array antenna 11 in which a plurality of antenna elements are arranged in a vertical direction; a transmission/reception unit 13 that transmits radar radio wave by radiating a plurality of beams to a plurality of regions with different elevation directions during a Pulse Repetition Interval (PRI) and receives reflection waves of each of the beams; a signal processing unit 14 that generates a transmission timing signal that sets the PRI as a period until completion of reception of all the reflection waves of the beams; and a transmission control unit 15 that generates a transmission signal according to the transmission timing signal.

Description

  Embodiments described herein relate generally to a meteorological radar apparatus and a meteorological observation method for observing meteorological phenomena such as rain and clouds in three dimensions.

  A conventional parabona antenna type weather radar emits a thin beam called a pencil beam, rotates 360 ° horizontally to acquire observation data for one plane, and then increases the antenna elevation angle to acquire the next plane. In this way, three-dimensional precipitation data is collected (see, for example, Non-Patent Document 1). It takes about 5 to 10 minutes to carry out this observation sequence, and sufficient temporal and spatial resolution has not been taken for observation of cumulonimbus clouds and the like that change every moment.

Supervised by Takashi Yoshida, “Revised Radar Technology”, The Institute of Electronics, Information and Communication Engineers, October 1, 1996, first edition, “Chapter 9 Weather Radar”, P238-253

  As described above, it has been difficult to detect a sudden and local phenomenon such as a tornado or a gust in a weather radar apparatus using a conventional parabolic antenna.

  An object of the present embodiment is to provide a meteorological radar apparatus and a meteorological observation method capable of reliably collecting three-dimensional meteorological data with high temporal and spatial resolution.

The meteorological radar apparatus according to the present embodiment includes a phased array type antenna unit in which a plurality of antenna elements are arranged in the vertical direction, and a pulse transmission repetition period (PRI: Pulse Repetition Interval). A transmission / reception unit that transmits a radar radio wave by radiating a plurality of beams and receives a reflected wave for each beam, and a transmission in which the PRI is a period until the end of the reception period of all the reflected waves of the beam A signal processing unit for generating a timing signal, a transmission control unit for generating a transmission signal according to the transmission timing signal,
It comprises.

  The meteorological observation method according to the present embodiment is a meteorological observation method used in a meteorological radar having a phased array antenna in which a plurality of antenna elements are arranged in the vertical direction, and includes a pulse transmission repetition period (PRI: Pulse). In Repetition Interval), a radar radio wave is transmitted by radiating a plurality of beams to a plurality of different areas in the elevation angle direction, a reflected wave for each beam is received, and the PRI is reflected on all reflected waves of the beam. A transmission timing signal that is a period until the end of the reception period is generated, and a transmission signal is generated according to the transmission timing signal.

The functional block diagram which shows the weather radar apparatus which concerns on this embodiment. The schematic diagram which shows an example of a transmission beam. The figure which shows the transmission / reception timing of Example 1. FIG. FIG. 6 is a diagram illustrating the number of receptions in the beam 1 in the case of the first embodiment. The figure which shows the transmission / reception timing of Example 2. FIG. FIG. 10 is a diagram illustrating the number of receptions in the beam 1 in the case of the second embodiment. The figure which shows the transmission / reception timing of Example 3. FIG. FIG. 10 is a diagram illustrating the number of receptions in the beam 1 in the case of the third embodiment. The figure which shows the example of a general transmission / reception timing.

  Hereinafter, a weather radar apparatus and a weather observation method according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a functional block diagram showing the configuration of the weather radar apparatus according to the present embodiment. In FIG. 1, this weather radar apparatus includes an antenna 11, a transmission / reception switch 12, a transmission / reception unit 13, a signal processing unit 14, and a transmission control unit 15.

  The antenna 11 is a one-dimensional phased array antenna in which a plurality of antenna elements are arranged in the vertical direction. The antenna element is constituted by, for example, a slot antenna. By arranging a plurality of slot waveguides, the beam direction in the elevation angle direction can be electrically controlled by phase scanning. Moreover, sharp directivity in the azimuth direction can be obtained by mechanically focusing the beam using a slot antenna.

  The transmission control unit 15 creates a transmission signal including phase control information for determining the transmission angle of the radar radio wave in the elevation angle direction according to a transmission timing signal from the signal processing unit 14 described later. The transmission / reception unit 13 amplifies this transmission signal and sends it as a radar radio wave from the antenna 11 to the air via the transmission / reception switch 12.

  When a reflected wave from a weather target such as precipitation arrives at the antenna 11, it is received by the transmission / reception unit 13 via the transmission / reception switch 12, A / D converted, and then subjected to I / Q detection. The signal processing unit 14 calculates received power and Doppler speed based on the I / Q signal detected by the transmission / reception unit 13.

  Next, an observation method performed by the weather radar apparatus configured as described above will be described. FIG. 2 is a schematic diagram illustrating an example of a transmission beam. The following description will be given assuming that the number of transmission beams N = 3.

  When a transmission timing signal is sent from the signal processing unit 14, the antenna 11 rotates the antenna in the horizontal direction by 360 ° in accordance with the transmission signal from the transmission control unit 15, and for each pulse transmission repetition period (PRI: Pulse Repetition Interval). Three transmission beams are radiated to different regions in the elevation angle direction. In this manner, the phased array type weather radar apparatus can collect three-dimensional weather data with improved temporal and spatial resolution.

  Here, FIG. 9 shows transmission timing generally assumed in the case where a plurality of transmission beams in one PRI are used. When a plurality of transmission beams are radiated for each PRI, radio waves cannot be received during radio wave transmission, resulting in a blank (a space that cannot be observed) as shown in FIG. That is, the number of blanks when transmitting radio waves N times within one PRI is (N−1) for each reception beam. Further, the number of blanks increases as the number of transmission beams in one PRI increases. In the case of a weather radar device, there is a problem that if there is a blank, the weather information in that space cannot be completely acquired. Hereinafter, in order to improve this problem, a transmission timing signal generated in the signal processing unit 14 will be described according to each embodiment.

Example 1
FIG. 3 is a diagram illustrating transmission / reception timings according to the first embodiment. In the first embodiment, only one wave of each beam is transmitted in the number of transmissions in each transmission direction (first transmission and second transmission). That is, as shown in FIG. 3, when PRI is set to the period until the end of the reception period of the pulse of the Nth beam, the number of blanks can be reduced. FIG. 4 shows the number of receptions at each reception timing in the beam 1 in the first embodiment. As can be seen from FIG. 4, there is a problem that there is a timing of the total number of receptions 0 at each reception timing.

(Example 2)
FIG. 5 is a diagram illustrating transmission / reception timings according to the second embodiment. In the second embodiment, the transmission order of each beam is changed for each PRI. FIG. 6 shows the number of receptions at each reception timing in the beam 1 in the case of the second embodiment. Since there is no timing with the total number of receptions 0 at each reception timing, the problem of the first embodiment can be solved.

(Example 3)
FIG. 7 is a diagram illustrating transmission / reception timings according to the third embodiment. In the third embodiment, the total number of receptions is averaged by further adjusting the transmission timing in the second embodiment. FIG. 8 shows the number of receptions at each reception timing in the beam 1 in the case of the third embodiment. Since the total number of receptions is averaged at each reception timing, in this way, the problem of the first embodiment can be solved more effectively.

  As described above, in this embodiment, by changing the generation position of the blank for each PRI, even when the number of pulses is increased by increasing the number of transmission beams in the PRI, weather observation that does not generate a complete blank Is possible. In addition, since the distance between the transmission beams is determined by the relative time difference between the received transmission beam and the other transmission beams, the blank of each reception beam is determined relative to the transmission beams as shown in FIGS. It is possible to prevent blanks from being generated in a specific space by changing the time difference. Therefore, according to the present embodiment, it is possible to reliably collect 3D weather data with high resolution in time and space.

  Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 11 ... Antenna, 12 ... Transmission / reception switch, 13 ... Transmission / reception part, 14 ... Signal processing part, 15 ... Transmission control part.

Claims (6)

A phased array type antenna unit in which a plurality of antenna elements are arranged in the vertical direction;
A transmission / reception unit that transmits a radar radio wave by radiating a plurality of beams to a plurality of regions different from each other in an elevation angle direction and receives a reflected wave for each beam in a pulse transmission repetition period (PRI: Pulse Repetition Interval); ,
A signal processing unit that generates a transmission timing signal that uses the PRI as a period until the end of the reception period of all reflected waves of the beam;
A transmission control unit for creating a transmission signal according to the transmission timing signal;
A weather radar apparatus comprising:   The weather radar apparatus according to claim 1, wherein the transmission control unit changes a transmission order of the beams for each PRI.   The weather radar apparatus according to claim 2, wherein the transmission control unit adjusts the transmission timing of the beam so that the number of receptions is averaged at the reception timing of the reflected wave. A meteorological observation method used in a meteorological radar having a phased array type antenna in which a plurality of antenna elements are arranged in a vertical direction,
During a pulse transmission repetition period (PRI: Pulse Repetition Interval), a radar radio wave is transmitted by radiating a plurality of beams to a plurality of regions different from each other in the elevation angle direction, and a reflected wave for each beam is received.
Generating a transmission timing signal with the PRI as a period until the end of the reception period of all reflected waves of the beam;
A meteorological observation method characterized by creating a transmission signal according to the transmission timing signal.   The weather observation method according to claim 4, wherein the transmission order of the beams is changed for each PRI.   6. The meteorological observation method according to claim 5, wherein the transmission timing of the beam is adjusted so that the number of receptions is averaged at the reception timing of the reflected wave.

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