JP2010122044A - Method for measuring beam orientation direction of multi-beam transmitting antenna, and multi-beam transmitting antenna subsystem using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring beam orientation direction of a multi-beam transmitting antenna capable of measuring highly accurately an actual beam orientation direction of each beam without pattern scanning, even when a plurality of beam orientation directions are displaced from each design value individually. <P>SOLUTION: The method includes: the first step of measuring beams 2(n) from a multi-beam transmitting antenna 1 approximately simultaneously at measuring points 3(m); the second step of determining at least two or more of relative values between two beams 2(1), 2(2) from each reception level measured at the measuring points 3(m) respectively; and the third step of determining a beam center of each beam minimizing the sum of squares of each difference between each relative value at the measuring points 3(m) and each relative value of each beam at the measuring points 3(m) acquired from a prescribed radiation pattern function showing the shape of each beam using a beam center direction as a parameter, and measuring the beam orientation direction of each beam at the measuring time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a beam pointing direction measuring method for a multi-beam transmission antenna and a multi-beam transmission antenna subsystem using the same.

  In general, a multi-beam transmitting antenna mounted on a satellite, particularly a multi-beam transmitting antenna using a large reflecting mirror, is different from the reflecting mirror due to a change in characteristics of a feeding circuit and thermal distortion of the reflecting mirror during operation. When the positional relationship with the secondary radiator antenna changes, there is a problem that the radiation pattern changes from a desired pattern. Therefore, there is a need for a technique for measuring the radiation pattern of a satellite-mounted multi-beam transmission antenna on the ground.

Conventionally, a beam directing direction (radiation pattern) measurement method of a multi-beam transmission antenna that measures an antenna radiation pattern on the ground is known (see, for example, Patent Document 1).
The method described in Patent Document 1 connects an existing reception antenna and transmission antenna mounted on a satellite for communication, receives a signal transmitted from the ground with the reception antenna, and receives a received radio wave from the transmission antenna. This is a method of measuring the sensitivity of the receiving antenna by sending it again to the ground. Specifically, for example, the radiation pattern of the receiving antenna is measured while changing the attitude of the satellite, changing the position of the ground antenna system, or changing the radiation pattern of the receiving antenna.

  Conventionally, as a method for shortening the measurement time, a plurality of beam test signals radiated from a multi-beam transmission antenna mounted on a satellite or the like are subjected to multiplexing such as frequency division and fixed to one. Detects the relative level difference of any two received powers of multiple beams received at the ground station almost simultaneously and received at the fixed ground station, and from the intersection of multiple contour curves based on the relative level difference, satellite etc. A method of detecting the direction of the radiation pattern of a transmitting antenna mounted on the antenna is also known (see, for example, Patent Document 2).

JP-A-10-160775 Japanese Patent Laid-Open No. 11-295366

In the case of a conventional method for measuring the beam directing direction of a multi-beam transmitting antenna, the method described in Patent Document 1 requires long-time measurement by changing the attitude of a satellite or changing a radiation pattern. Therefore, there is a possibility that the antenna mirror surface changes during the measurement period, and there is a problem that an accurate radiation pattern cannot be measured.
Further, considering that the satellite service is stopped during the measurement of the radiation pattern, there is a problem that the measurement during the satellite operation becomes practically difficult.

  Further, in the method described in Patent Document 2, in order to shorten the measurement time, when measuring the pattern of the multi-beam transmission antenna, the reception electric field strength of each multi-beam is received almost simultaneously by one fixed ground station. However, based on the comparison between the received level relative value and the design value in one fixed ground station, the actual antenna pattern is measured by detecting how much the antenna pattern direction is displaced from the design value. When multiple beams radiated from a multi-beam transmission antenna are displaced in the same direction as a whole, the antenna pattern can be measured accurately, but for example, when the antenna pattern rotates as a whole, If the beam direction is individually deviated from the design value, the antenna pattern cannot be measured accurately. There was a cormorant problem.

  The present invention has been made to solve the above-described problems, and measures signals of a plurality of beams radiated from a multi-beam transmitting antenna at a plurality of measurement points almost simultaneously, and a plurality of signals at each measurement point. The difference between the relative value of the beam at a plurality of measurement points obtained from a predetermined radiation pattern function representing the shape of each beam, using the relative value of the beam reception level and the beam center direction of the plurality of beams as parameters. By obtaining the beam center of each beam that minimizes the sum of squares of the beam, even if the beam pointing directions of the plurality of beams are individually displaced from the design values, pattern scanning (satellite attitude control, etc.) is not performed. An object of the present invention is to obtain a beam pointing direction measuring method for a multi-beam transmitting antenna that can accurately measure the actual beam pointing direction of each beam. That.

  A beam directing direction measuring method of a multi-beam transmitting antenna according to the present invention is a beam directing direction measuring method of a multi-beam transmitting antenna that radiates a plurality of beams, and a plurality of beam signals radiated from the multi-beam transmitting antenna are At least two types of relative values between the two beams are determined based on the first step of measuring almost simultaneously at a plurality of measurement points whose positions are known and the reception levels of the plurality of beams measured at each of the plurality of measurement points. The plurality of measurement points obtained from the second step obtained above, a plurality of relative values at each of the plurality of measurement points, and a predetermined radiation pattern function representing the shape of each beam with the beam center directions of the plurality of beams as parameters. Find the beam center of each beam that minimizes the sum of squares of the difference between the relative value of the beam at A third step of measuring the beam pointing direction of each beam at the time of measurement is obtained with a.

According to the present invention, even when the beam directivity directions of a plurality of beams are individually displaced from the design values, the actual beam directivity directions of the respective beams are highly accurate without performing pattern scanning (such as satellite attitude control). Can be measured.
In addition, when measuring signals of multiple beams radiated from a multi-beam transmitting antenna, pattern scanning is not required and long-time measurement is not required. It becomes possible to obtain the beam directing directions of a plurality of beams.

Embodiment 1 FIG.
FIGS. 1-5 is explanatory drawing which shows the beam orientation direction measuring method of the multi-beam transmission antenna based on Embodiment 1 of this invention.
FIG. 1 schematically shows the relationship between the beam 2 (n) of the multi-beam transmission antenna 1 and the measurement antenna 3 (m).

  In FIG. 1, each signal level of a plurality of beams 2 (n) (n = 1, 2, 3,..., N) radiated from the multi-beam transmitting antenna 1 is a plurality of signals whose installation positions are known. Measurement is performed at the measurement antenna 3 (m) (m = 1, 2, 3,..., M).

Here, each angular coordinate of the measurement antenna 3 (m) (m = 1, 2, 3,..., M) is (ξ _m , η _m ) (m = 1, 2, 3,... , M). Hereinafter, unless otherwise stated, the position of the measurement antenna 3 (m) will be referred to as a measurement point 3 (m).

In FIG. 1, the signal levels of two beams 2 (1) and 2 (2) out of a plurality (N) of radiated beams 2 (n) are represented by a plurality (M) of measurement points 3 (M). Consider the case of measuring at two measurement points 3 (1) and 3 (2) of m).
At this time, the antenna pattern arrangement of the beams 2 (1) and 2 (2) in the vicinity of the measurement points 3 (1) and 3 (2) is as shown in FIG. 2) are patterns in different directions.

FIG. 2 shows a case where the signal levels of the two beams 2 (1) and 2 (2) are measured at the measurement points 3 (1) and 3 (2).
At this time, the radiation patterns of the beams 2 (1) and 2 (2) on the straight line 4 (one-dot chain line) connecting the measurement point 3 (1) and the measurement point 3 (2) are as shown in FIG. Become.

In FIG. 3, the signal levels P ₁ (ξ ₁ , η ₁ ), P ₁ (ξ ₂ , η ₂ ) of the beam 2 (1) measured at each measurement point 3 (1), 3 (2), The signal levels P ₂ (ξ ₁ , η ₁ ) and P ₂ (ξ ₂ , η ₂ ) of the beam 2 (2) measured at each measurement point 3 (1) and 3 (2) are shown.

Here, when the received signal level is considered as a dB value, the received signal level relative value ΔP _{1,2 of the} two beams 2 (1) and 2 (2) measured at the respective measurement points 3 (1) and 3 (2). (Ξ ₁ , η ₁ ) and ΔP _1,2 (ξ ₂ , η ₂ ) are expressed by the difference between the signal levels P ₁ and P ₂ as in the following equation (1).

Next, the radiation pattern of each beam 2 (1), 2 (2) is approximated, and the beam center coordinates (ξ _{c, n} , η _{c, n} ) (n = 1, 2, 3,... Consider a predetermined radiation pattern function P _n ⁰ (ξ, η, ξ _{c, n} , η _{c, n} ) (n = 1, 2, 3,..., N) with N as a parameter. .

Here, suitable beam center direction of the beam when selecting 2 (1), 2 (2) given radiation a pattern function ^{_{P 1 0 (ξ, η,}} ξ c, 1, η c, 1), P Each radiation pattern P ₁ ⁰ (ξ, η) of ₂ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ) on the straight line 4 connecting the measurement point 3 (1) and the measurement point 3 (2) , P ₂ ⁰ (ξ, η) is as shown in FIG.

FIG. 4 shows the radiation patterns P ₁ ⁰ (ξ, η) and P ₂ ⁰ (ξ, η) of the beams 2 (1) and 2 (2) at the time of the measurement in FIG.
Measurement point 3 (1) obtained from each radiation pattern function P ₁ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ), P ₂ ⁰ (ξ, η, ξ _{c, 1} , η _c, 1) , 3 relative signal level [Delta] P _{1, 2} ⁰ in _{(2) (ξ 1, η} 1), ΔP 1,2 0 (ξ 2, η 2) ^{_{is, P n 0 (n = 1,2,3}} , · .., N) is represented by a dB value, it is represented by the difference between the radiation pattern functions P ₁ ⁰ and P ₂ ⁰ as shown in the following equation (2).

On the other hand, FIG. 5 is an explanatory diagram showing an example of a radiation pattern. Each beam center of the beams 2 (1) and 2 (2) at the time of measurement and a predetermined radiation pattern function P ₁ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ), P ₂ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ), beam centers (ξ _{c, 1} , η _{c, 1} ), (ξ _{c, 2} , η _{c) , 2} ) are in agreement with each other.
Here, in order to easily recognize each radiation pattern, two overlapping radiation patterns are shown as being slightly shifted.

In FIG. 5, the measurement point 3 (1) and the measurement point 3 (2) in the case where the beam centers of the two beams at the time of measurement coincide with the beam centers of the predetermined radiation pattern function are shown. The radiation pattern of the beams 2 (1) and 2 (2) and a predetermined radiation pattern function P ₁ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ), P at the time of measurement on the connecting straight line 4 The radiation patterns P ₁ ⁰ (ξ, η) and P ₂ ⁰ (ξ, η) of ₂ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ) are shown.

In FIG. 4, the beam centers of the beams 2 (1) and 2 (2) at the time of measurement and predetermined radiation pattern functions P ₁ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ), P ₂ ^Since each beam center (ξ _{c, 1} , η _{c, 1} ) and (ξ _{c, 2} , η _{c, 2} ) of ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ) is different, each measurement Received signal level relative values ΔP _1,2 (ξ ₁ , η ₁ ), ΔP _1,2 (ξ ₂ , η ₂ ) obtained from measured values at points 3 (1) and 3 ( ₂ ), and a predetermined radiation pattern function ^{_{P 1 0 (ξ, η,}} ξ c, 1, η c, 1), P 2 0 (ξ, η, ξ c, 1, η c, 1) is obtained from the relative signal level [Delta] P _{1, 2} ⁰ ( _{ξ 1, η 1), ΔP} 1,2 0 (ξ 2, and eta _2), considered to be a different value respectively.
Therefore, the sum of squares of the difference between the two becomes a finite value larger than a certain positive value ε as shown in the following formula (3).

On the other hand, in FIG. 5, the beam centers of the beam beams 2 (1) and 2 (2) at the time of measurement and predetermined radiation pattern functions P ₁ ⁰ (ξ, η, ξ _{c, 1} , η _{c of} each beam). _{, 1} ), P ₂ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ) beam centers (ξ _{c, 1} , η _{c, 1} ), (ξ _{c, 2} , η _{c, 2} ) Therefore, the received signal level relative values ΔP _1,2 (ξ ₁ , η ₁ ) and ΔP _1,2 (ξ ₂ , η ₂ ) obtained from the measured values at the respective measurement points 3 (1) and 3 (2). And a relative signal level obtained from a predetermined radiation pattern function P ₁ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ), P ₂ ⁰ (ξ, η, ξ _{c, 1} , η _{c, 1} ) ^{_{ΔP 1,2 0 (ξ 1, η}} 1), ΔP 1,2 0 (ξ 2, η 2) and, respectively become equal.
Therefore, the sum of squares of the difference between the two is “0” as shown in the following equation (4).

Thus, the beam center of each beam at the time of measurement and the beam center (ξ _{c, 1} , η _{c, 1} ), (ξ _{c, 2} , η _{c, 2} ) of a predetermined radiation pattern function of each beam are obtained. If they match, the above equation (4) is considered to hold.
Conversely, if the beam centers (ξ _{c, 1} , η _{c, 1} ) and (ξ _{c, 2} , η _{c, 2} ) of each beam having a predetermined radiation pattern function satisfying the equation (4) are known. The beam centers of the beams 2 (1) and 2 (2) at the time of measurement are obtained.

However, in consideration of the measurement error at the time of measurement, the beam center (ξ _{c, 1} , η _{c, 1} ) of a predetermined radiation pattern function such that the sum of squares is “0” as in equation (4), (Ξ _{c, 2} , η _{c, 2} ) may not exist.
Therefore, the beam centers (ξ _{c, 1} , η _{c, 1} ) and (ξ _{c, 2} , η _{c, 2} ) of a predetermined radiation pattern function are obtained so as to minimize the following equation (5).

In Expression (5), the received signal level relative values ΔP _1,2 (ξ ₁ , η ₁ ), ΔP _1,2 (ξ ₂ ) obtained from the measured values at the respective measurement points 3 (1) and 3 (2). , and eta _2), relative signal level [Delta] P obtained from predetermined radiation pattern function ^{_{1,2 0 (ξ 1, η 1}} ), ΔP 1,2 0 (ξ 2, the square sum of the difference between eta ₂₎ The beam centers (ξ _{c, 1} , η _{c, 1} ), (ξ _{c, 2} , η _{c, 2} ) of a predetermined radiation pattern function of each beam 2 (1), 2 (2), which are minimized. Will be asked.

  In the above description, the case where two beams (one kind of relative value) are measured at two measurement points is taken as an example. However, a predetermined radiation pattern function that satisfies Equation (4) without including uncertainty is used. In practice, at least three beams (two kinds of relative values) are measured at at least two measurement points, or at least two beams (one kind of relative value) are obtained. Value) must be measured at at least three measurement points (in this case, the three measurement points do not exist on the same straight line).

Therefore, in the first embodiment of the present invention, the beam center (ξ _{c, n} , η _{c, n} ) of a predetermined radiation pattern function of each beam is actually set so as to minimize the following expression (6). ) (N = 1, 2, 3,..., N).

However, the received signal level relative value ΔP _{n, n + 1} and the relative signal level ΔP _{n, n + 1} ⁰ are expressed by the following equation (7).

When the received signal level relative value P _{n, n + 1} is not defined, that is, when the intensity of the beam 2 (n), 2 (n + 1) is not measured at a certain measurement point 3 (m), the above equation (6) It is assumed that the corresponding terms of “n” and “m” are not calculated.

  Therefore, by obtaining each beam center of a predetermined radiation pattern function that satisfies the equation (6), even when the beam directing direction of each beam at the time of measurement is individually displaced from the design value, pattern scanning or the like can be performed. Without performing this, it becomes possible to measure the beam directing direction of each beam.

  As described above, the beam directing direction measuring method of the multi-beam transmitting antenna according to the first embodiment of the present invention is for measuring the beam directing direction of the multi-beam transmitting antenna 1 that emits a plurality of beams 2 (n). A first step of measuring the signals of the plurality of beams 2 (n) radiated from the multi-beam transmitting antenna 1 substantially simultaneously at a plurality of measurement points 3 (m) whose positions are known; and a plurality of measurements A second step of obtaining at least two types of relative values between the two beams from the reception levels of the plurality of beams 2 (n) measured at each of the points 3 (m); and a plurality of measurement points 3 (m). A plurality of measurement values obtained from a predetermined radiation pattern function representing a shape of each beam with a plurality of relative values in each and a beam center direction of the plurality of beams 2 (n) as parameters. A third step of determining the beam center of each beam that minimizes the sum of squares of the difference between the relative value of the beam at point 3 (m) and measuring the beam pointing direction of each beam at the time of measurement; It has.

As a result, even when the beam directing directions of the plurality of beams 2 (n) are individually displaced from the design values, the actual beam directing directions of the respective beams can be changed without performing pattern scanning (satellite attitude control or the like). It can be measured with high accuracy.
In addition, when measuring signals of a plurality of beams 2 (n) radiated from the multi-beam transmitting antenna 1, pattern scanning is not required and long-time measurement is not required. It becomes possible to obtain the beam directing directions of a plurality of beams easily and in a short time.

Embodiment 2. FIG.
In the first embodiment (FIGS. 1 to 5), the case where the beam directing directions of the plurality of beams 2 (n) radiated from the multi-beam transmitting antenna 1 are individually displaced from the design values is considered. However, even when the antenna pattern 5 (solid line) at the time of measurement is shifted by a certain amount (Δξ, Δη) from the desired antenna pattern 6 (dotted line) in the design value as a whole as shown in FIG. Good.

FIG. 6 is an explanatory diagram showing a beam pointing direction measuring method for a multi-beam transmission antenna according to Embodiment 2 of the present invention, and shows an assumed antenna pattern arrangement of each beam.
In FIG. 6, the antenna pattern 5 at the time of measurement is not displaced individually in the beam pointing direction of each beam 2 (n) (see FIG. 1), but as a whole, a certain amount from the antenna pattern 6 at the design value. The figure shows a case where (Δξ, Δη) is shifted and the antenna pattern 6 ′ after the shift is further rotated by an angle δ as a whole with respect to a certain rotation center (ξ _r , η _r ).

For example, as shown in FIG. 6, each beam center in a design value of a plurality of beams 2 (n) radiated from the multi-beam transmission antenna 1 (see FIG. 1) is represented by (ξ _{o, n} , η _{o, n} ) (n = 1, 2, 3,..., N), and each beam is rotated and rotated by an angle δ with respect to a certain center of rotation (ξ _r , η _r ), and further shifted by (Δξ, Δη) think of.
At this time, the beam directing direction (ξ _{o, n} ′, η _{o, n} ′) of each beam 2 (n) after the rotation δ and the shift (Δξ, Δη) are generated is given by the following equation (8). It is done.

Therefore, in the second embodiment of the present invention, the beam center (ξ _{c, n} , η _{c, n} ) (n = 1, 2, 3, 3) of a predetermined radiation pattern function of each beam satisfying the above-described equation (6). .., N) and the equation given by the following equation (9) is solved for the rotation center (ξ _r , η _r ), the rotation angle δ, and the shift amount (Δξ, Δη).

  However, in Equation (9), when the number of beams N = 2, there are five unknowns for the four variables, so the equation of Equation (9) cannot be solved. Therefore, at least three beams (two kinds of relative values) and at least two or more measurement points 3 (m) are required.

Thus, based on the rotation center (ξ _r , η _r ) and rotation angle δ obtained from the equation (9), and the shift amount (Δξ, Δη), the beam directing direction of each beam at the time of measurement is designed as a whole ( Even when the antenna pattern 6) is rotated and shifted from the antenna pattern 6), the rotation center and angle of the rotation change and the shift amount can be obtained without performing pattern scanning.

As described above, according to the second embodiment of the present invention, the third step for measuring the beam directing direction of the multi-beam transmitting antenna 1 includes the beam centers (ξ _r , η _r ) and the beam center in the desired radiation pattern (designed antenna pattern 6) are used to solve the equation (9) to obtain the antenna pattern 5 from the desired radiation pattern at the time of measurement. Since the step of measuring the shift amount and the rotation amount and the rotation center direction of the antenna pattern is included, even if the beam directing directions of the plurality of beams 2 (n) are shifted as a whole, the rotation is performed without performing pattern scanning. The rotation center, rotation angle, and shift amount of the change can be obtained, and the same effects as described above can be obtained.

Embodiment 3 FIG.
In the second embodiment (FIG. 6), by solving the equation (9), when the beam directing direction of each beam at the time of measurement changes as a whole from the design value and changes in the rotation, the rotation changes. The center, the rotation angle, and the shift amount were obtained, and the rotation center (ξ _{c, n} , η _{c, n} ) was converted into each parameter (ξ _r , η _r ), δ and (Δξ, Δη) Parameters (ξ _r , η _r ), δ, and (Δξ, Δη) that minimize the following equation (10) may be obtained.

Expression (10) represents the square sum (sum) of the received signal level relative value and the relative signal level.
However, in the equation (10), the received signal level relative value ΔP _{n, n + 1} and the relative signal level ΔP _{n, n + 1} ⁰ are given by the above equation (7), and the rotation center (ξ _{c, n} , η _{c , N} ) are converted into parameters (ξ _r , η _r ), δ, and (Δξ, Δη) by the above-described equation (9).

Therefore, by obtaining the rotation center (ξ _r , η _r ), the rotation angle δ and the shift amount (Δξ, Δη) that satisfy the equation (10), the beam directing direction of each beam at the time of measurement is designed as a whole. Even when the rotation change and the shift change occur from, the rotation center and rotation angle of the rotation change and the shift amount can be obtained without performing pattern scanning, as described above.

As described above, according to the third embodiment of the present invention, the third step for measuring the beam directing direction of the multi-beam transmitting antenna 1 is performed such that the predetermined radiation pattern function is a beam center in a desired radiation pattern. In the case of a function having the shift amount (Δξ, Δη) and the rotation amount ξ from the direction and the rotation center of the desired radiation pattern as parameters, a plurality of reception level relative values at a plurality of measurement points 3 (m) , Parameters (ξ _r , η _r ), δ and (Δξ, Δη) that minimize the sum of squares of the differences between the relative values between the beams at a plurality of measurement points obtained from a predetermined radiation pattern function And measuring the amount of shift and rotation of the antenna pattern from the desired radiation pattern at the time of measurement, and the center of rotation of the antenna pattern. The same effects as those of the second embodiment described above are achieved.

Embodiment 4 FIG.
In the third embodiment, the parameter that minimizes the equation (10) is obtained. However, the radiation pattern of the plurality of beams 2 (n) radiated from the multi-beam transmission antenna 1 is approximated, and As a predetermined radiation pattern function using the beam center coordinates as a parameter, a quadratic function in which the constant term and the coefficient of the quadratic term are equal may be adopted as in the following equation (11).

In Expression (11), P ₀ is the maximum value of a predetermined radiation pattern function, K is a constant coefficient representing the shape of the pattern.
FIG. 7 is an explanatory view showing a beam pointing direction measuring method for a multi-beam transmitting antenna according to Embodiment 4 of the present invention. The same reference numerals as those described above are given to the same parts as those described above (see FIG. 6). Yes.

In the fourth embodiment of the present invention, a case is considered in which the beam directing direction of each beam 2 (n) is not individually displaced from the design value but shifted from the design value as a whole.
Therefore, as shown in Expression (11) and FIG. 7 _{, assuming} that the beam center of each beam is shifted by a certain amount from the beam center (ξ _{o, n} , η _{o, n} ) in the desired radiation pattern, the shift amount ( Δξ, Δη) are used as parameters.

At this time, at a certain measurement point 3 (m) (ξ _m , η _m ), two beams 2 (n), 2 (2) out of a plurality of beams radiated from the multi-beam transmission antenna 1 (see FIG. 1). n + 1) received signal level relative value ΔP _{n, n + 1} (ξ _m , η _m ) obtained from measurement and relative signal level ΔP _{n, n + 1} ⁰ (ξ _m , η _m ) obtained from a predetermined radiation pattern function of each beam. ) Is expressed by the following formula (12).

  As apparent from the equation (12), the difference amount is a linear equation with respect to the shift amount (Δξ, δη), and the problem of minimizing the above equation (6) is solved by the linear least square method. Can do. That is, the shift amount (Δξ, Δη) that minimizes the equation (6) is obtained from the condition that the value obtained by differentiating the equation (6) by Δξ and Δη is “0”. It can ask for.

However, in the equation (13), the variables A _{n, n + 1} , B _{n, n + 1} , C _{n, n + 1} , and D _{n, n + 1} are given by the following equation (14).

  Therefore, by obtaining the shift amount (Δξ, Δη) using equation (13), even when the beam pointing direction of each beam at the time of measurement is shifted from the design value as a whole, it is easily performed without performing pattern scanning. The shift amount can be obtained.

  As described above, according to the fourth embodiment of the present invention, the third step for measuring the beam directing direction of the multi-beam transmitting antenna 1 includes a predetermined radiation pattern function, a constant term and a quadratic term. Are equal to each other and are a quadratic function with a shift amount from the beam center direction in a desired radiation pattern as a parameter, a plurality of reception level relative values at a plurality of measurement points and a plurality of quadratic functions obtained from the quadratic function. A step of obtaining a beam shift amount (Δξ, Δη) that minimizes a sum of squares of a difference between the relative value between the beams at the measurement point by solving the equation (13), and an antenna pattern at the time of measurement. And a step of measuring a shift amount from a desired radiation pattern (antenna pattern 6 at the time of design). Therefore, the same effects as those of the third embodiment are included. Unlikely to.

Although not particularly mentioned in the first to fourth embodiments, the control of the multi-beam transmission antenna 1 and the measurement antenna 3 (m) and various arithmetic processes are performed in the multi-beam transmission antenna 1 and the measurement antenna 3 ( Needless to say, the method is performed by a computer system (not shown) connected to m). The method of measuring the beam direction of the multi-beam transmission antenna according to any one of the first to fourth embodiments described above is applied to the multi-beam transmission antenna sub- Even if it is applied to the system, the same effects can be obtained.

It is explanatory drawing which shows the beam directivity direction measuring method of the multi-beam transmission antenna which concerns on Embodiment 1 of this invention as a whole system structure. It is explanatory drawing which shows the antenna pattern arrangement | positioning at the time of the measurement of Embodiment 1 of this invention. It is explanatory drawing which shows the radiation pattern of each beam on the straight line which connects the two measurement points in Embodiment 1 of this invention. It is explanatory drawing which shows a radiation pattern in case the beam center of each beam at the time of the measurement of Embodiment 1 of this invention differs from each beam center of a predetermined radiation pattern function. It is explanatory drawing which shows a radiation pattern in case the beam center of each beam at the time of measurement of Embodiment 1 of this invention and each beam center of a predetermined radiation pattern function correspond. It is explanatory drawing which shows the antenna pattern arrangement | positioning at the time of the measurement and design in Embodiment 2 of this invention. It is explanatory drawing which shows the antenna pattern arrangement | positioning at the time of the measurement and design in Embodiment 4 of this invention.

Explanation of symbols

  1 multi-beam transmission antenna, 2 (1) to 2 (N) beams, 3 (1) to 3 (M) measurement antenna, 4 straight line connecting two measurement points, 5 antenna pattern (arrangement) during measurement, 6 Antenna pattern (arrangement) at design value.

Claims (5)

A method of measuring a beam direction of a multi-beam transmitting antenna that radiates a plurality of beams,
A first step of measuring signals of a plurality of beams radiated from the multi-beam transmitting antenna at a plurality of measurement points whose positions are known substantially simultaneously;
A second step of determining at least two types of relative values between two beams from the reception levels of the plurality of beams measured at each of the plurality of measurement points;
The relative value of the beam at the plurality of measurement points obtained from a plurality of relative values at each of the plurality of measurement points and a predetermined radiation pattern function representing the shape of each beam with the beam center direction of the plurality of beams as parameters. A third step of obtaining a beam center of each beam that minimizes a sum of squares of a difference between the value and a beam directing direction of each beam at the time of measurement;
A method of measuring a beam pointing direction of a multi-beam transmitting antenna. The third step includes
By using a beam center of the plurality of beams and a beam center in a desired radiation pattern to solve a predetermined equation, the shift amount and the rotation amount of the antenna pattern from the desired radiation pattern at the time of measurement, The method of measuring a beam pointing direction of a multi-beam transmitting antenna according to claim 1, further comprising: measuring a rotation center direction of the antenna pattern. The third step includes
When the predetermined radiation pattern function is a function with the amount of shift and rotation from the beam center direction in the desired radiation pattern and the rotation center of the desired radiation pattern as parameters,
Each parameter that minimizes the sum of squares of a difference between a plurality of reception level relative values at the plurality of measurement points and a relative value between the beams at the plurality of measurement points obtained from the predetermined radiation pattern function A step of seeking
Measuring a shift amount and a rotation amount of the antenna pattern from the desired radiation pattern at the time of measurement, and a rotation center of the antenna pattern;
The method of measuring a beam pointing direction of a multi-beam transmitting antenna according to claim 1, wherein The third step includes
When the predetermined radiation pattern function is a quadratic function in which the coefficients of the constant term and the quadratic term are equal and the shift amount from the beam center direction in the desired radiation pattern is a parameter,
A beam shift amount that minimizes a sum of squares of a difference between a plurality of reception level relative values at the plurality of measurement points and a relative value between the beams at the plurality of measurement points obtained from the quadratic function, Obtaining by solving a predetermined equation;
Measuring the shift amount of the antenna pattern from the desired radiation pattern at the time of measurement;
The method of measuring a beam pointing direction of a multi-beam transmitting antenna according to claim 1, wherein   5. A multi-beam transmission antenna subsystem using the method of measuring a beam pointing direction of a multi-beam transmission antenna according to any one of claims 1 to 4.

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