JP2003050276A - Bistatic doppler radar system having two-plane switching antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bistatic Doppler radar system equipped with a receiving station having a two-plane switching antenna for observing two dual Doppler analysis ranges. SOLUTION: This bistatic Doppler radar system having the two-plane switching antenna is equipped with a transmitting station T comprising a Doppler radar and the bistatic receiving station R installed at a prescribed distance from the transmitting station T. The bistatic receiving station R has the two-plane switching antenna ATa and ATb for observing by one receiver, two arc-shaped dual Doppler analysis ranges on both sides of a base line BL determined by the transmitting station T and the receiving station R.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bistatic Doppler radar system having a two-sided switching antenna, and more particularly to a bistatic Doppler radar system having a two-sided switching antenna mainly used for weather observation such as wind speed field. .

[0002]

2. Description of the Related Art A conventional radar is a monostatic Doppler radar in which a transmitting station and a receiving station are physically installed at the same place. On the other hand, a system in which the transmitter station and the receiver station are physically separated from each other is called a bistatic radar.

As shown in FIG. 7, a bistatic Doppler radar system (or network) includes one main radar (transmitting station) T and a plurality of (three in this case) remote receiving stations (receivers). ) R1, R2, and R3. Only the main radar T transmits and the receiving stations R1, R2,
R3 receives the scattering from the observation target (for example, rainfall) by the non-scanning type antenna having wide angle characteristics. The arrow in FIG. 7 is the horizontal wind velocity vector (wind velocity field) obtained by the observation.

[0004]

The disadvantage of the bistatic Doppler radar system is that the monostatic
Compared to the Doppler radar, the receiving station cannot obtain sufficient reception intensity for weak scattered waves, and conversely, when very strong scattered waves are present, the effects of antenna side lobes and multiple scattering of the main radar are considered. It is easy to receive. Ultimately, the problem regarding the reception strength can be solved by installing a large number of remote receiving stations (that is, widening the dual Doppler analysis range) and effectively combining the data.

From this point of view, the present inventor has studied the bistatic Doppler radar system, particularly the receiving station, and found the following.

That is, theoretically, the dual Doppler analysis ranges K1 and K2 of the receiving station R are circles on both sides of a line (baseline BL) connecting the transmitting station T and the receiving station R as shown in FIG. Spread in an arc (hatched area). However, conventionally, in actual observation, one receiving station R observes only one of the dual Doppler analysis ranges K1 and K2. Therefore, at one receiving station R, the baseline B
If the two dual Doppler analysis ranges K1 and K2 on both sides of L can be observed, the analysis range per one receiver can be expanded. Therefore, the problem of the reception intensity can be solved and the observation accuracy can be improved. It is thought to contribute to improvement. Further, if one receiving station R can observe two dual Doppler analysis ranges K1 and K2, it is considered that the analysis processing of the data can be facilitated (simplified). Furthermore, it is considered that the cost of installing the receiving station R can be reduced.

It is an object of the present invention to provide a bistatic Doppler radar system having a two-sided switching antenna provided with a receiving station having a two-sided antenna for observing two dual Doppler analysis ranges.

[0008]

SUMMARY OF THE INVENTION A bistatic Doppler radar system having a two-sided switching antenna according to the present invention comprises a transmitter station composed of a Doppler radar and a bistatic receiver station provided at a predetermined distance from the transmitter station. Equipped with. The bistatic receiving station has a two-plane switching antenna for observing two arc-shaped dual Doppler analysis ranges on both sides of a baseline defined by the transmitting station and the receiving station with one receiver.

According to the bistatic Doppler radar system having the two-sided switching antenna of the present invention, the receiving station observes two arc-shaped dual Doppler analysis ranges on both sides of the baseline by the two-sided antenna. . Therefore, a single receiving station can observe a dual Doppler analysis range that is twice as wide as the conventional one, so that the analysis range can be significantly expanded with a small increase in cost. As a result, in the bistatic Doppler radar system, it is possible to solve the above-mentioned problem of reception intensity and improve observation accuracy. Also, because one receiving station can observe two dual Doppler analysis ranges,
The analysis process of the data can be facilitated (simplified), and the cost of installing the receiving station can be reduced.

[0010]

1 and 2 are configuration diagrams of a bistatic Doppler radar system, showing the configuration of the bistatic Doppler radar system of the present invention. 1 and 2 are schematic diagrams, and the sizes of the antennas ATa and ATb are shown to be large with respect to the scale of distance.

As shown in FIG. 1, the bistatic Doppler radar system includes a transmitting station T and a transmitting station T.
And at least one receiving station R provided at a predetermined distance (for example, several tens Km). A straight line (base line BL) connecting the transmitting station T and the receiving station R is determined at the positions of the transmitting station T and the receiving station R as shown in FIGS. 1 and 2.
Two arc-shaped dual Doppler analysis ranges (dual lobes) K1 and K2 on both sides thereof are determined. The dual Doppler analysis ranges K1 and K2 are ranges in which the wind velocity vector of practical accuracy can be observed (analyzed) by the radar system. As will be described later in detail, one receiving station R in this example observes both dual Doppler analysis ranges K1 and K2 with two antennas ATa and ATb.

The region K adjacent to the baseline BL
3 is an area where the wind velocity vector cannot be originally calculated with practical accuracy, for example. The region K3 where the observation data is blank is eliminated by providing a plurality of receiving stations R and arranging the dual Doppler analysis ranges K1 and K2 so as to overlap each other.

In the bistatic Doppler radar system, only the transmitting station T consisting of one Doppler radar transmits the radio wave, and one or a plurality of receiving stations R reflect the reflected wave from the observation target (for example, rainfall) S. (Scattering) of two antennas ATa and AT having a wide angle characteristic of non-scanning type
Receive at b. As shown in FIG. 3, the receiving station R includes a two-sided switching antenna AT (ATa and ATb) and a changeover switch S.
W, one receiver 1. The receiver 1 includes a changeover switch control unit 2 in addition to a known amplifier, signal processing circuit, and the like.

In this example, as shown in FIG. 4, the two antennas are two-sided switching antennas AT. The two-sided switching antenna AT is a two-sided (two) antenna ATa and ATb.
Has a configuration integrally formed. The two-sided antennas ATa and ATb observe two dual Doppler analysis ranges K1 and K2 on both sides of the baseline BL.

As shown in FIG. 4, the two-sided switching antenna AT is a waveguide slot antenna (Slotted Waveguide Antenna).
nna) 31, 32 and reflectors 41, 42. In this example, a fixed fan beam waveguide slot antenna to which (two pairs of) reflectors 41 and 42 are added is used.

Here, it is necessary to maximize the dual Doppler analysis ranges K1 and K2 (the range shown by the dotted line in FIG. 2) in order to observe efficiently and accurately at low cost. That is, so the effective beam width B of each antenna
W is set. This is a waveguide slot antenna 3
It depends on how to cut the slots at 1, 32.

At this time, the center of each antenna beam (the position where the intensity of the beam is maximum) is also determined as shown by the alternate long and short dash line in FIG. The angle formed by the center of each antenna beam and the baseline BL is referred to as the installation angle θ of the two-plane switching antenna AT. When the present inventor paid attention to the relationship between the installation angle θ and the dual Doppler analysis range K1 (or K2), as shown in FIG.
It was found that the installation angle θ that maximizes the area of the analysis range K1 (or K2) does not change even if L is changed from 15 km to 60 km. That is, the analysis range K1 (or K
It was found that the installation angle θ that maximizes 2) does not depend on the length of the baseline BL.

Therefore, in the two-sided switching antenna AT of the present invention, the installation angle θ formed by the center of the antenna beam and the base line BL is fixed in each of the two-sided antennas. Even if it does in this way, 2 of the present invention
According to the surface switching antenna AT, it is not necessary to adjust the installation angle θ so as to maximize the analysis ranges K1 and K2 each time the installation location is changed. That is, it is possible to observe the analysis areas K1 and K2 of the maximum area regardless of the length of the baseline BL while keeping the installation angle θ constant.

The changeover switch SW is, as shown in FIG.
It is connected to the two-sided switching antenna AT. Changeover switch SW
For this, a well-known mechanical low-speed switch that has a low insertion loss and is inexpensive is used. The changeover switch control unit 2 uses the antenna azimuth information of the transmitting radar of the transmitting station T (described later).
The changeover switch SW is switched based on If necessary, an amplifier (not shown) is installed directly below each of the waveguide slot antennas 31 and 32 of the two-plane switching antenna AT to amplify the signal from the corresponding waveguide slot antennas 31 and 32. Then, a signal may be sent to the changeover switch SW and the receiver 1.

The receiving station R is a communication network N such as a telephone line.
Is connected to the transmitting station T via the, and various communications are performed with this. Through this communication, various information is transmitted from the transmitting station T to the receiving station R. The information transmitted includes, for example, the antenna azimuth information in addition to the time and phase of the known transmission pulse. The delay in this transmission is a time that does not hinder switching of the changeover switch SW, as described later. That is, the antenna azimuth information can be transmitted in real time when viewed from the switching (though not for other information). Although not shown, it is a personal computer having a communication function, which is connected to the receiving station R, that actually communicates with the transmitting station T via the communication network N such as a telephone line.

The receiving station R (the changeover switch control unit 2 thereof) is
The antenna azimuth information of the Doppler radar is received from the transmitting station T, and the changeover switch SW is switched based on the received antenna azimuth information. That is, the changeover switch SW
As shown in FIG. 6, when the transmitting station T (the antenna of the transmitting radar of the transmitting station) faces the one side (for example, ATa) of the two-plane switching antenna AT of the baseline BL,
Switching is performed so that a received signal from one (ATa) of the two-sided switching antenna AT is selected and output to the receiver 1. The receiver 1 receives and processes a signal from the two-sided switching antenna AT via the changeover switch SW.

In general, the azimuth angle is represented by an angle in which the true north N is "0 degree". In FIG. 6, assuming that the azimuth of the baseline BL is “BL (AZ)”, the antenna ATa is BL
(AZ) +180 to 360 degrees (that is, 0 degrees) and belongs to the side (Face-A) from 0 degrees to BL (AZ), and the antenna ATb is from BL (AZ) to BL (AZ).
It belongs to the side up to +180 (Face-B). That is, assuming that the current antenna azimuth is "AZ", BL (AZ)
In the case of +180 <AZ <BL (AZ) (in the case of Face-A), the antenna ATa is selected, and BL (AZ) <A
In the case of Z <BL (AZ) +180 (in the case of Face-B), the antenna ATb may be selected.

Specifically, BL (AZ) in FIG. 6 is about 60 degrees, and the current antenna azimuth AZ is the transmitting station T.
Is given as the antenna azimuth angle information of the Doppler radar, and the speed at which the antenna of the Doppler radar makes one revolution is 20 seconds, for example. Therefore, the changeover switch SW
Selects the signal from the antenna ATb and inputs it to the receiver 1 during the period when the antenna azimuth information is 60 degrees to 240 degrees, and the antenna azimuth information is 240 degrees to 360 degrees (0 degrees) to 60 degrees. The signal from the antenna ATa is selected and input to the receiver 1 during a period of time. Since the orbital speed of the antenna of the Doppler radar is 20 seconds, it is possible to sufficiently switch even with the low-speed changeover switch SW. Also,
The delay in the transmission of the antenna azimuth angle information by the communication network N such as a telephone line is generally not a problem for the antenna rotation speed. In the receiver 1, the observation data of a wide area called the dual Doppler analysis ranges K1 and K2 is 1
It can be obtained by observing twice. At this time, since the range along the baseline BL is outside the analysis range, the two ranges K1 and K
It is not necessary to consider the continuity of data at the second joint, and data processing can be facilitated.

As a result, the number of installed receiving stations R is 1 in the dual Doppler analysis ranges K1 and K2 according to the present invention.
If it is an individual, it will be twice as large as the conventional one. Actually, in the case of the example of FIG. 7, in addition to the first dual Doppler analysis range shown in FIG. 7, for each of the three receiving stations R1, R2, and R3, the receiving station and the transmitting station T A second dual Doppler analysis range (not shown) whose axis of line symmetry is the baseline BL connecting to and can be observed. As a result, the same three receiving stations R1, R2, and R3 can realize a much larger dual Doppler analysis range than in the case of FIG. That is, when a plurality of receiving stations R are installed, the actual dual Doppler analysis ranges normally overlap with each other as shown in FIG. 7, and therefore the analysis ranges are not simply doubled. However, it is possible to improve the calculation accuracy of the wind velocity field in the overlapping portion of the analysis range. Therefore, it is possible to improve the wind field accuracy with a smaller number of receiving stations than in the past.

The present invention has been described above according to the embodiments thereof, but the present invention can be variously modified within the scope of the gist thereof.

For example, the structure of the two-plane switching antenna AT is not limited to the structure shown in FIG. That is, the two antennas ATa and ATb do not necessarily have to be formed substantially integrally. For example, two independently formed antennas ATa and ATb observe two dual Doppler analysis ranges K1 and K2 on both sides of the baseline BL, and are physically close to the changeover switch SW. It has only to be installed.

[0027]

According to the present invention, in a bistatic Doppler radar system having a two-sided switching antenna, a two-sided switching antenna for observing two dual Doppler analysis ranges is provided at a receiving station, thereby providing one dual-sided switching antenna. Since the receiving station can observe the dual Doppler analysis range which is twice as wide as the conventional one, the analysis range can be expanded with a small increase in cost, and the above-mentioned reception intensity problem in the bistatic Doppler radar system can be solved. It is possible to solve the problem, improve the observation accuracy, facilitate the analysis processing of the data, and reduce the installation cost of the receiving station.

[Brief description of drawings]

FIG. 1 is a block diagram of a bistatic Doppler radar system.

FIG. 2 is a configuration diagram of a bistatic Doppler radar system.

FIG. 3 is a configuration diagram of a bistatic Doppler radar system.

FIG. 4 is a configuration diagram of a two-side switching antenna.

FIG. 5 is an explanatory diagram of a relationship between an installation angle and an analysis range.

FIG. 6 is an explanatory diagram of a bistatic Doppler radar system.

FIG. 7 is a background explanatory view of the invention.

FIG. 8 is a background explanatory diagram of the invention.

[Explanation of symbols] T transmitter R receiving station S observation target

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5J070 AB01 AC13 AD03 AE12 AK01                       AK19 AK22 AK27 BD02

Claims (4)

[Claims] 1. A transmission station composed of a Doppler radar, and a bistatic reception station provided at a predetermined distance from the transmission station, the two stations on both sides of a baseline defined by the transmission station and the reception station. A bistatic Doppler radar system with a two-sided switching antenna, comprising: a receiving station having a two-sided switching antenna for observing a single arc-shaped dual Doppler analysis range with one receiver. 2. The changeover switch according to claim 1, further comprising: a changeover switch connected to the two-sided changeover antenna; and a receiver for receiving and processing a signal from the two-sided changeover antenna via the changeover switch. Bistatic Doppler radar system with a two-sided switching antenna. 3. The receiving station according to claim 2, wherein the receiving station receives antenna azimuth angle information of the Doppler radar from the transmitting station and switches the changeover switch based on the received antenna azimuth angle information. Bistatic Doppler radar system with dual switching antenna. 4. The two-plane switching antenna according to claim 1, wherein an angle formed by the center of the antenna beam and the baseline is fixed in each of the two-plane antennas. Bistatic Doppler radar system with surface switching antenna.