JP3619160B2 - Reflector antenna reception phase calibration device - Google Patents

Description

【００２５】
と表される。さらに、第１の受信機５ａ、第２の受信機５ｂのそれぞれの位相変動量が等しいものとすると、δｒｅｃは０と考えてよい。よって、複数の較正用波源からの電波により観測されたΔＬｏｉより、関数Ｆを決定することにより副反射鏡変位量を求めることができる。副反射鏡変位量を知ることができれば、例えば幾何光学法により副反射鏡変位時の観測天体からの電波の位相に及ぼす影響を計算することができるため、補正量を決定できる。
【００２６】
本構成における較正用波源の位置は、主反射鏡の変位による影響を受けない。しかし、観測天体からの電波の位相については、主反射鏡の変位によって誤差を生じる。一方、主反射鏡の変位は、図２及び図３に示すように、仰角に応じて主反射鏡のｚ方向の変位とたわみが大きくなる傾向にある。この場合、主反射鏡変位前の観測天体からの電波８ａ’と主反射鏡変位後の観測天体からの電波８ａ’’の位相すなわち光路長の差と、主反射鏡変位前の基準天体からの電波８ｂ’と主反射鏡変位後の基準天体からの電波８ｂ’’の光路長の差は対称性を考慮するとほぼ等しいと考えることができる。よって、実際の観測量である観測天体からの電波８ａと基準天体からの電波８ｂの位相差には上記の変形は影響を及ぼさないことがわかる。
【００２７】
一方、副反射鏡の変位は図４に示すように、重力の影響を考えると、ｘ軸方向の変位が支配的であることがわかる。図４において、観測天体からの電波８ａは副反射鏡が変位する前にはＭ_Ａ→Ｓ_Ａを通り第１の受信ホーン４ａに達するが、副反射鏡変位後にはＭ_Ａ→Ｓ’_Ａとなり、変位によって光路長は増加する。一方基準天体からの電波８ｂは副反射鏡変位によって光路はＭ_Ｂ→Ｓ_ＢからＭ_Ｂ→Ｓ’_Ｂと変化し、逆に光路長は短くなる。よって両者の位相差は副反射鏡変位によって大きな誤差を有することがわかる。
【００２８】
このように、本実施の形態の発明に係る反射鏡アンテナ受信位相較正装置は、回転対称な主反射鏡１と、主反射鏡１に対向する副反射鏡２と、主反射鏡１中心を通る主反射鏡鏡軸に対して軸対称に配置された２つの受信ホーン４ａ，４ｂと、受信ホーン４ａ，４ｂを介して電波を受信する２つの受信機５ａ，５ｂと、２つの受信機５ａ，５ｂの出力に基づいて電波の位相差を検出するデジタル相互相関器６と、副反射鏡２を支えるステイ１０と、主反射鏡１を支持するために主反射鏡１の裏面の所定の部分のみに設けられたバックストラクチャ１１と、複数の較正用波源３とを有する反射鏡アンテナ受信位相較正装置において、複数の較正用波源３は、主反射鏡１上のステイ１０近傍もしくは裏面にバックストラクチャ１１が配置されている場所に配設されている。そのため、主反射鏡１上の変位の影響を受けない位置に較正用波源３を設置することにより、支配的な誤差である副反射鏡２の変位量を推定し、天体観測時の補正値を求めることができるという効果を有する。
【００２９】
実施の形態２．
図５はこの発明の実施の形態２の反射鏡アンテナ受信位相較正装置の概略構成図である。図５において、実施の形態１の図１と同じ番号を付したものは図１と同じはたらきをする。また図５において、座標系Ｏ−ＸＹＺは図１の座標系と同様のものである。
【００３０】
図５において、第１の受信ホーン４ａ及び第２の受信ホーン４ｂは、図５に示す座標系において、ＸＺ面内に位置し、Ｚ軸に対して対称な位置に配置されている。また、２つの較正用波源３は主反射鏡上のステイ１０の近傍、もしくはバックストラクチャ１１の交点の、仰角によって変位しない位置で、かつＹＺ面内のＮ１、Ｎ２に配置されている。さらに、実施の形態１と同様に、第１の受信機５ａ、第２の受信機５ｂのそれぞれの位相変動量が等しいものとして、δｒｅｃは０と考えている。
【００３１】
図５に示すように、較正用波源３がＹＺ面内に配置されている場合、例えばＮ１の位置に配置されている較正用波源３を考えると、第１の受信ホーン、第２の受信ホーンに至る途中での副反射鏡２との交点Ｓ１_Ａ，Ｓ１_Ｂは、対称性よりＸ座標の符号が異なるのみで同じ値をとる。このような対称性を用いることにより、実施の形態１で述べたような、副反射鏡２のＺ軸に対して非対称な変位であるＸ軸方向の変位ΔＸ_Ｓ、および副反射鏡２の中心を通りＹ軸に平行な軸まわりの副反射鏡２の回転量Δθ_ＹＳについて以下の式が成り立つ。
【００３２】
【数２】

【００３３】
上式においてｉは１，２の値をとり、Ｎ１，Ｎ２の位置に配置された較正用波源３を示している。また、Ａｉ，Ｂｉ，Ｃｉは、以下の式で表される。
【００３４】
【数３】

【００３５】
上式において、（ｘｉ，ｙｉ，ｚｉ）は、較正用波源３より第１の受信ホーンに至るまでの変位前の副反射鏡２との交点Ｓ_ｉＡの座標を示し、（ｎ_ｘｉ，ｎ_ｙｉ，ｎ_ｚｉ）はそれらの点上での副反射鏡２の単位法線ベクトルを示す。また、ｇｉは較正用波源３より放射した電波を第１の受信ホーン、Ｂで受信した場合の光路長差ΔＬｏｉより求められる量であり、較正用波源３より副反射鏡２上での交点Ｓ_ｉＡに向かう光線の単位方向ベクトルをｅ_１，ｉＡ、反射後の単位方向ベクトルをｅ_２，ｉＡ、さらに副反射鏡が変位しない場合の光路長差ΔＬｆｉとすると
【００３６】
【数４】

【００３７】
で表される量である。副反射鏡が変位しない場合の光路長差ΔＬｆｉは計算値を用いて求めることができる。また、鏡面系を天頂方向に向けたときのΔＬｏｉは、上記の副反射鏡のＸ軸方向の変位ΔＸ_Ｓ、および副反射鏡２の中心を通りＹ軸に平行な軸まわりの副反射鏡２の回転量Δθ_ＹＳといったＺ軸に対して非対称な成分を含まない値であり、その値をもってΔＬｆｉとすることもできる。
【００３８】
上式を連立させて解くことにより、副反射鏡２のＸ軸方向の変位ΔＸ_Ｓ、および副反射鏡２の中心を通りＹ軸に平行な軸まわりの副反射鏡２の回転量Δθ_ＹＳを一意に決定することができる。副反射鏡変位量を知ることができれば、例えば幾何光学法により副反射鏡変位時の観測天体からの電波の位相に及ぼす影響を計算することができるため、補正量を決定できる。
【００３９】
このように、本実施の形態の発明に係る反射鏡アンテナ受信位相較正装置においては、複数の較正用波源３は、主反射鏡中心を通り２つの受信ホーンと主反射鏡鏡軸を含む面に垂直な面内に配設されている。そのため、主反射鏡１上の変位の影響を受けない位置に較正用波源３を設置することにより、支配的な誤差である副反射鏡２の変位量を推定し、天体観測時の補正値を求めることができるという効果を有する。
【００４０】
また、デジタル相互相関器６は、較正用波源３から放射された電波の位相信号に基づいて、副反射鏡２の鏡軸に対して非対称な変位成分を一意に決定する。そのため、２つの較正用波源３を設置するのみで支配的な誤差である副反射鏡の変位量である副反射鏡２のＸ軸方向の変位、および副反射鏡２の中心を通りＹ軸に平行な軸まわりの副反射鏡２の回転量を一意に決定することができるという効果を有する。
【００４１】
実施の形態３．
図６はこの発明の実施の形態３の反射鏡アンテナ受信位相較正装置の要部の斜視図である。図６において、実施の形態１の図１と同じ番号を付したものは図１と同じはたらきをする。図６において、１２は受信機取付板である。
【００４２】
上述の実施の形態１及び２においては、較正用波源３を主反射鏡１上に配置しているが、本実施の形態においては、この較正用波源３を受信ホーン４ａ，４ｂが設置されている受信ホーン取付板上１２に設置している。
【００４３】
このように、本実施の形態の発明に係る反射鏡アンテナ受信位相較正装置は、回転対称な主反射鏡１と、主反射鏡１に対向する副反射鏡２と、主反射鏡１中心を通る主反射鏡鏡軸に対して軸対称に配置された２つの受信ホーン４ａ，４ｂと、受信ホーン４ａ，４ｂを介して電波を受信する２つの受信機５ａ，５ｂと、２つの受信機５ａ，５ｂの出力に基づいて電波の位相差を検出するデジタル相互相関器６と、副反射鏡２を支えるステイ１０と、主反射鏡１を支持するために主反射鏡１の裏面の所定の部分のみに設けられたバックストラクチャ１１と、複数の較正用波源３とを有する反射鏡アンテナ受信位相較正装置において、複数の較正用波源は、受信ホーン取付板上１２に配設されている。そのため、主反射鏡１の仰角による変形の影響を受けることがない。また、特に実施の形態２において、第１の受信ホーン４ａ及び第２の受信ホーン４ｂと較正用波源３の位置関係を限定しているが、本実施の形態においては、同一の板の上に設置しているために、仰角の変化によって重力により第１の受信ホーン４ａ及び第２の受信ホーン４ｂや較正用波源３が変位しても独立に変位することなく、第１の受信ホーン４ａ及び第２の受信ホーン４ｂと較正用波源３の位置関係は保たれたまま変位するという効果を有する。
【００４４】
実施の形態４．
図７はこの発明の実施の形態４の反射鏡アンテナ受信位相較正装置の要部の断面図である。図７において、実施の形態１の図１と同じ番号を付したものは図１と同じはたらきをする。
【００４５】
上述の実施の形態１及び２においては、較正用波源３を直接バックストラクチャ１１に取付け、主反射鏡１に穴（貫通孔）を空けることにより電波を放射できるような構成としている。
【００４６】
このように、本実施の形態の発明に係る反射鏡アンテナ受信位相較正装置は、回転対称な主反射鏡１と、主反射鏡１に対向する副反射鏡２と、主反射鏡１中心を通る主反射鏡鏡軸に対して軸対称に配置された２つの受信ホーン４ａ，４ｂと、受信ホーン４ａ，４ｂを介して電波を受信する２つの受信機５ａ，５ｂと、２つの受信機５ａ，５ｂの出力に基づいて電波の位相差を検出するデジタル相互相関器６と、副反射鏡２を支えるステイ１０と、主反射鏡１を支持するために主反射鏡１の裏面の所定の部分のみに設けられたバックストラクチャ１１と、複数の較正用波源３とを有する反射鏡アンテナ受信位相較正装置において、複数の較正用波源は、バックストラクチャ１１に固定され、主反射鏡１の所定の位置には、較正用波源３から放出される電波を通過させる為の貫通孔が設けられている。そのため、主反射鏡１の仰角による変形の影響を受けることがより小さくなり、推定において誤差要因となる較正用波源３の変位を抑えることができるという効果を有する。
【００４７】
実施の形態５．
図８はこの発明の実施の形態５の反射鏡アンテナ受信位相較正装置の概略構成図である。図８において、実施の形態１の図１と同じ番号を付したものは図１と同じはたらきをする。また図８において、１３は受信機位相モニタである。
【００４８】
上述の実施の形態１乃至４においては、受信機５ａ，５ｂによる位相変動量はともに等しいとして、観測量には影響を及ぼさないとしている。しかしながら、実際には同一の特性を示すことは難しい。よって受信機５ａ，５ｂによる位相変動量を、受信機位相モニタ１３でモニタすることにより、受信機５ａ，５ｂによる位相変動量を補正値として用いる。
【００４９】
このように、本実施の形態の発明に係る反射鏡アンテナ受信位相較正装置は、２つの受信機５ａ，５ｂの出力に基づき、電波の位相変動量をモニタする受信機位相モニタ１３を有する。そのため、受信機５ａ，５ｂの位相変動も切り分けて補正として用いることができるという効果を有する。
【００５０】
【発明の効果】
この発明に係る反射鏡アンテナ受信位相較正装置は、回転対称な主反射鏡と、主反射鏡に対向する副反射鏡と、主反射鏡中心を通る主反射鏡鏡軸に対して軸対称に配置された２つの受信ホーンと、受信ホーンを介して電波を受信する２つの受信機と、２つの受信機の出力に基づいて電波の位相差を検出するデジタル相互相関器と、副反射鏡を支えるステイと、主反射鏡を支持するために主反射鏡の裏面の所定の部分のみに設けられたバックストラクチャと、複数の較正用波源とを有する反射鏡アンテナ受信位相較正装置において、複数の較正用波源は、主反射鏡上のステイ近傍もしくは裏面にバックストラクチャが配置されている場所に配設されている。そのため、主反射鏡上の変位の影響を受けない位置に較正用波源を設置することにより、支配的な誤差である副反射鏡の変位量を推定し、天体観測時の補正値を求めることができるという効果を有する。
【００５１】
また、この発明に係る反射鏡アンテナ受信位相較正装置は、回転対称な主反射鏡と、主反射鏡に対向する副反射鏡と、主反射鏡中心を通る主反射鏡鏡軸に対して軸対称に配置された２つの受信ホーンと、受信ホーンを介して電波を受信する２つの受信機と、２つの受信機の出力に基づいて電波の位相差を検出するデジタル相互相関器と、副反射鏡を支えるステイと、主反射鏡を支持するために主反射鏡の裏面の所定の部分のみに設けられたバックストラクチャと、複数の較正用波源とを有する反射鏡アンテナ受信位相較正装置において、複数の較正用波源は、受信ホーン取付板上に配設されている。そのため、主反射鏡の仰角による変形の影響を受けることがない。
【００５２】
また、この発明に係る反射鏡アンテナ受信位相較正装置は、回転対称な主反射鏡と、主反射鏡に対向する副反射鏡と、主反射鏡中心を通る主反射鏡鏡軸に対して軸対称に配置された２つの受信ホーンと、受信ホーンを介して電波を受信する２つの受信機と、２つの受信機の出力に基づいて電波の位相差を検出するデジタル相互相関器と、副反射鏡を支えるステイと、主反射鏡を支持するために主反射鏡の裏面の所定の部分のみに設けられたバックストラクチャと、複数の較正用波源とを有する反射鏡アンテナ受信位相較正装置において、複数の較正用波源は、バックストラクチャに固定され、主反射鏡の所定の位置には、較正用波源から放出される電波を通過させる為の貫通孔が設けられている。そのため、主反射鏡の仰角による変形の影響を受けることがより小さくなり、推定において誤差要因となる較正用波源３の変位を抑えることができるという効果を有する。
【００５３】
また、複数の較正用波源は、条件で、かつ主反射鏡中心を通り２つの受信ホーンと主反射鏡鏡軸を含む面に垂直な面内に配設されている。そのため、主反射鏡上の変位の影響を受けない位置に較正用波源を設置することにより、支配的な誤差である副反射鏡の変位量を推定し、天体観測時の補正値を求めることができるという効果を有する。
【００５４】
また、デジタル相互相関器は、較正用波源から放射された電波の位相信号に基づいて、副反射鏡の鏡軸に対して非対称な変位成分を一意に決定する。そのため、支配的な誤差である副反射鏡の変位量である副反射鏡のＸ軸方向の変位、および副反射鏡の中心を通りＹ軸に平行な軸まわりの副反射鏡２の回転量を一意に決定することができるという効果を有する。
【００５５】
また、２つの受信機の出力に基づき、電波の位相変動量をモニタする受信機位相モニタをさらに有する。そのため、受信機の位相変動も切り分けて補正として用いることができるという効果を有する。
【図面の簡単な説明】
【図１】この発明の実施の形態１の反射鏡アンテナ受信位相較正装置の概略構成図である。
【図２】この発明の実施の形態１を説明するための主反射鏡のＺ方向変位時の天体からの位相の変化の概略図である。
【図３】この発明の実施の形態１を説明するための主反射鏡がたわみを持つ場合の天体からの位相の変化の概略図である。
【図４】この発明の実施の形態１を説明するための副反射鏡が変位した場合の天体からの位相の変化の概略図である。
【図５】この発明の実施の形態２の反射鏡アンテナ受信位相較正装置の概略構成図である。
【図６】この発明の実施の形態３の反射鏡アンテナ受信位相較正装置の要部の斜視図である。
【図７】この発明の実施の形態４の反射鏡アンテナ受信位相較正装置の要部の断面図である。
【図８】この発明の実施の形態５の反射鏡アンテナ受信位相較正装置の概略構成図である。
【図９】従来の２ビームアンテナによる観測を説明する概念図である。
【図１０】従来の較正用波源を配置する手法を説明する説明図である。
【符号の説明】
１ 主反射鏡、１ａ 回転対称な主反射鏡、１ｂ Ｚ方向に変位した主反射鏡、１ｃ たわんだ主反射鏡、２ 副反射鏡、２ａ 変位した副反射鏡、３ 較正用波源、４ 受信ホーン、４ａ 第１の受信ホーン、４ｂ 第２の受信ホーン、５ 受信機、５ａ 第１の受信機、５ｂ 第２の受信機、６ デジタル相互相関器、７ａ 観測天体、７ｂ 基準天体、８ａ 観測天体からの電波、８ａ’ 主反射鏡変位前の観測天体からの電波、８ａ’’ 主反射鏡変位後の観測天体からの電波、８ｂ 基準天体からの電波、８ｂ’ 主反射鏡変位前の基準天体からの電波、８ｂ’’ 主反射鏡変位後の基準天体からの電波、９ 大気のゆらぎ、１０ ステイ、１１ バックストラクチャ、１２ 受信ホーン取付板、１３ 受信機位相モニタ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a phase calibration apparatus for a radio telescope, for example, and more particularly to a reflector antenna reception phase calibration apparatus that estimates a mirror displacement amount from a phase difference between two reception horns.
[0002]
[Prior art]
Conventionally, as this kind of reflector antenna reception phase calibration device, for example, N.I. Kawaguchi, T .; Sasao, S .; Manabe, “Dual Beam VLBI Technologies for Precision Astrometry of VERA Project”, SPIE, March, 2000. There is something shown in.
[0003]
FIG. 8 is a schematic configuration diagram of a conventional reflector antenna calibration apparatus disclosed in the above-mentioned document. In FIG. 8, 1 is a rotationally symmetric main reflecting mirror, 2 is a sub-reflecting mirror facing the main reflecting mirror 1, 3 is a calibration wave source, 4a and 4b are on the main reflecting mirror axis passing through the center of the main reflecting mirror 1. Two receiving horns 5a and 5b arranged symmetrically with respect to the axis are two receivers for receiving radio waves via the receiving horns, and 6 is a phase difference of radio waves based on the outputs of the two receivers 5a and 5b. A digital cross-correlator for detection, 10 is a stay for supporting the sub-reflecting mirror 2, 11 is a back structure for supporting the main reflecting mirror 1, and 13 is a receiver phase monitor. The back structure 11 is a framework for supporting the large-diameter main reflecting mirror 1 and extends radially from the center on the back surface of the main reflecting mirror 1. The stay 10 has one end fixed to the back structure 11 and the other end supporting the sub-reflecting mirror 2.
[0004]
FIG. 9 is a conceptual diagram for explaining observation with a two-beam antenna. In the figure, 4a is a first receiving horn, 4b is a second receiving horn, 5a is a first receiver, 5b is a second receiver, 7a is an observation object, 7b is a reference object, and 8a is an observation object. , 8b is a radio wave from the reference celestial body, and 9 is a fluctuation of the atmosphere.
[0005]
Next, the operation will be described. In order to observe the position of celestial bodies with high accuracy using a radio interferometer with multiple radio telescopes, it is necessary to accurately measure the phase of the radio waves from the observation celestial bodies at each radio telescope antenna. . However, this measurement has been difficult due to fluctuations due to the earth's atmosphere, displacement of the specular system, and errors due to receiver fluctuations. Further, since the displacement of the mirror system due to its own weight varies depending on the elevation angle, the phase error due to the displacement of the mirror system of the radio wave from the observation object depends on the elevation angle of the radio telescope.
[0006]
In order to solve this problem, as shown in FIG. 9, there has been proposed a method of simultaneously observing a reference celestial object simultaneously with an observation celestial object using a radio telescope having two beams. The first receiver 5a and the second receiver 5b simultaneously receive the radio wave 8a from the observation celestial body and the radio wave 8b from the reference celestial body located on the paraxial axis of the observation celestial body through the same mirror system. At this time, it can be considered that the radio wave 8 a from the observation celestial body and the radio wave 8 b from the reference celestial body have passed through a region having substantially the same atmospheric fluctuation 9. Therefore, by correcting the reception phase from the observation celestial body 7a using the phase of the reference celestial body 7b, an error due to atmospheric fluctuation 9 can be corrected. In such two-beam observation, it is not necessary to observe the phase of each celestial body, and usually the phase difference between two celestial bodies is often observed.
[0007]
On the other hand, a method of arranging a calibration wave source 3 as shown in FIG. 10 has been proposed for errors due to the displacement of the mirror surface system and fluctuations at the receiver. As shown in FIG. 10, radio waves are emitted from a plurality of calibration wave sources 3 arranged on the main reflecting mirror 1, and the radio waves are received by the receiving horn 4. The phase of the received signal includes the phase change caused by the displacement of the main reflecting mirror 1 and the sub-reflecting mirror 2 and the phase change of the receiver 5, and this phase change amount is corrected with respect to the receiving phase of the observation object. By doing so, errors due to mirror surface displacement and receiver fluctuations can be removed. In addition, this method has an effect that an error due to the displacement of the mirror system can be detected according to the elevation angle of the radio telescope.
[0008]
As for the displacement of the mirror surface system, complete calibration can be performed only for the signal path from the celestial body with the calibration wave source position as the reflection point. However, the phase from the actual celestial body is obtained as a result of integrating the radio waves reflected at all points of the main reflector 1 and the sub-reflector 2. For complete calibration, the phase on the main reflector 1 It is necessary to arrange a number of term corrective wave sources 3 at the same position.
[0009]
[Problems to be solved by the invention]
In the reflector antenna calibration apparatus configured as described above, the phase from the celestial body is obtained as a result of integrating the radio waves reflected at all points of the main reflector 1 and the sub-reflector 2 and is completely calibrated. In order to perform the above, there is a problem that it is necessary to arrange a number of term corrective wave sources 3 on the main reflecting mirror 1.
[0010]
Further, when only the phase difference between the two receiving horns is observed as in the case of the two-beam observation, there is a problem that a specific correction amount is not obtained.
[0011]
The present invention has been made to solve the above-described problems, and uses a small number of calibration wave sources to estimate a mirror displacement that most contributes to an error from a phase difference between two receiving horns. An object is to obtain a reception phase calibration apparatus.
[0012]
[Means for Solving the Problems]
The reflector antenna reception phase calibration apparatus according to the present invention is arranged symmetrically about the main reflector mirror axis passing through the center of the main reflector, the sub-reflector facing the main reflector, the sub-reflector facing the main reflector Supports two received horns, two receivers that receive radio waves via the receiving horns, a digital cross-correlator that detects the phase difference of radio waves based on the outputs of the two receivers, and a sub-reflector A reflector antenna reception phase calibration apparatus having a stay, a back structure provided only on a predetermined portion of the back surface of the main reflector to support the main reflector, and a plurality of calibration wave sources, The wave source is disposed at a place where the back structure is disposed in the vicinity of the stay or on the back surface of the main reflecting mirror.
[0013]
The reflector antenna reception phase calibration apparatus according to the present invention is rotationally symmetric with respect to the main reflector, the sub-reflector facing the main reflector, and the axis of the main reflector passing through the center of the main reflector. Two receiving horns arranged in the receiver, two receivers for receiving radio waves via the receiving horns, a digital cross-correlator for detecting a phase difference of radio waves based on outputs of the two receivers, and a sub-reflector A reflector antenna reception phase calibration apparatus having a stay supporting the main reflector, a back structure provided only on a predetermined portion of the back surface of the main reflector to support the main reflector, and a plurality of calibration wave sources. The calibration wave source is disposed on the receiving horn mounting plate.
[0014]
The reflector antenna reception phase calibration apparatus according to the present invention is rotationally symmetric with respect to the main reflector, the sub-reflector facing the main reflector, and the axis of the main reflector passing through the center of the main reflector. Two receiving horns arranged in the receiver, two receivers for receiving radio waves via the receiving horns, a digital cross-correlator for detecting a phase difference of radio waves based on outputs of the two receivers, and a sub-reflector A reflector antenna reception phase calibration apparatus having a stay supporting the main reflector, a back structure provided only on a predetermined portion of the back surface of the main reflector to support the main reflector, and a plurality of calibration wave sources. The calibration wave source is fixed to the back structure, and a through-hole for allowing radio waves emitted from the calibration wave source to pass through is provided at a predetermined position of the main reflector.
[0015]
Further, the plurality of calibration wave sources are arranged in a plane perpendicular to a plane including the two receiving horns and the main mirror axis along the condition and passing through the center of the main mirror.
[0016]
The digital cross-correlator uniquely determines an asymmetric displacement component with respect to the mirror axis of the sub-reflecting mirror based on the phase signal of the radio wave radiated from the calibration wave source.
[0017]
In addition, a receiver phase monitor is further provided for monitoring the amount of radio wave phase fluctuation based on the outputs of the two receivers.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram of a reflector antenna reception phase calibration apparatus according to Embodiment 1 of the present invention. In FIG. 1, 1 is a rotationally symmetric main reflecting mirror, 2 is a sub-reflecting mirror facing the main reflecting mirror 1, 3 is a calibration wave source, 4a and 4b are on the main reflecting mirror axis passing through the center of the main reflecting mirror 1. Two receiving horns 5a and 5b arranged symmetrically with respect to the axis are two receivers for receiving radio waves via the receiving horns, and 6 is a phase difference of radio waves based on the outputs of the two receivers 5a and 5b. A digital cross-correlator for detection 10 is a stay for supporting the sub-reflecting mirror 2, and 11 is a back structure for supporting the main reflecting mirror 1. The back structure 11 is a framework for supporting the large-diameter main reflecting mirror 1 and extends radially from the center on the back surface of the main reflecting mirror 1. The stay 10 has one end fixed to the back structure 11 and the other end supporting the sub-reflecting mirror 2. A coordinate system O-XYZ in the drawing indicates a coordinate system in which the focal point of the sub-reflecting mirror 2 is the origin and the rotation axis of the rotationally symmetric main reflecting mirror 1a is the Z axis.
[0019]
FIG. 2 is a schematic diagram of a phase change from the celestial body when the main reflecting mirror is displaced in the Z direction for explaining the first embodiment of the present invention. In FIG. 2, 1b is the main reflector displaced in the Z direction, 8a 'is the radio wave from the observation object before displacement of the main reflector, 8a''is the radio wave from the observation object after displacement of the main reflector, and 8b' is the main wave. Radio waves from the reference celestial body before displacement of the reflecting mirror, 8b ″, indicates radio waves from the reference celestial body after displacement of the main reflector.
[0020]
FIG. 3 is a schematic diagram of a phase change from a celestial body when the main reflecting mirror has a deflection for explaining the first embodiment of the present invention. In FIG. 3, reference numeral 1c denotes a bent main reflecting mirror. FIG. 4 is a schematic diagram of a change in phase from the celestial body when the sub-reflecting mirror is displaced for explaining the first embodiment of the present invention.
[0021]
1, FIG. 2 and FIG. 3, the first receiving horn 4a and the second receiving horn 4b are located in the XZ plane in the coordinate system shown in FIG. Has been. A plurality of calibration wave sources 3 are arranged in the vicinity of the stay 10 on the main reflecting mirror 1 or at positions where the stay 10 and the back structure 11 are not displaced depending on the elevation angle.
[0022]
Next, the operation will be described. In the reflecting mirror antenna calibration apparatus shown in FIG. 1, as shown in FIG. 1, radio waves are radiated from a plurality of calibration wave sources 3 arranged on the main reflecting mirror 1, and the radio waves are radiated from the first receiving horn 4a and the first receiving horn 4a. 2 reception horn 4b. Based on the received signal, the digital cross-correlator 6 detects the phase difference between the signals of the first receiving horn 4a and the second receiving horn 4b.
[0023]
The detected phase difference is output by the digital cross-correlator 6 as a corresponding difference in optical path length. If the optical path length difference at this time is ΔLoi, the optical path length difference is the rotationally symmetric displacement of the main reflecting mirror 1a, the displacement of the sub-reflecting mirror 2, and the phase fluctuation amount of the first receiver 5a and the second receiver 5b. This amount includes the effects of However, since the calibration wave source 3 is disposed on the main reflecting mirror that is not displaced by the elevation angle, the influence of the displacement of the rotationally symmetric main reflecting mirror 1a is small. Therefore, the factor of the fluctuation amount included in ΔLoi is due to the displacement of the sub-reflecting mirror 2 and the phase fluctuation amount of the first receiver 5a and the second receiver 5b. Therefore, when the displacement amount of the sub-reflecting mirror 2 is δs and the phase fluctuation amounts of the first receiver 7a and the second receiver 7b are δrec,
[0024]
[Expression 1]

[0025]
It is expressed. Furthermore, if the phase fluctuation amounts of the first receiver 5a and the second receiver 5b are equal, δrec may be considered to be zero. Therefore, the sub-reflector displacement amount can be obtained by determining the function F from ΔLoi observed by radio waves from a plurality of calibration wave sources. If the amount of displacement of the sub-reflector can be known, for example, the influence on the phase of the radio wave from the observation object at the time of displacement of the sub-reflector can be calculated by the geometric optical method, so that the amount of correction can be determined.
[0026]
The position of the calibration wave source in this configuration is not affected by the displacement of the main reflector. However, an error occurs in the phase of the radio wave from the observation object due to the displacement of the main reflecting mirror. On the other hand, as shown in FIGS. 2 and 3, the displacement of the main reflecting mirror tends to increase the displacement and deflection of the main reflecting mirror in the z direction according to the elevation angle. In this case, the difference between the phase of the radio wave 8a ′ from the observation object before displacement of the main reflector and the radio wave 8a ″ from the observation object after displacement of the main reflector, that is, the optical path length, and the difference from the reference object before displacement of the main reflector. It can be considered that the difference in optical path length between the radio wave 8b ′ and the radio wave 8b ″ from the reference celestial body after displacement of the main reflector is substantially equal in consideration of symmetry. Therefore, it can be seen that the above deformation does not affect the phase difference between the radio wave 8a from the observation celestial body and the radio wave 8b from the reference celestial body, which are actual observation quantities.
[0027]
On the other hand, as shown in FIG. 4, it is understood that the displacement of the sub-reflecting mirror is dominant in the x-axis direction considering the influence of gravity. In FIG. 4, the radio wave 8a from the observation celestial body is M before the sub-reflector is displaced. _A → S _A , And reaches the first receiving horn 4a. _A → S ' _A Thus, the optical path length increases due to the displacement. On the other hand, the radio wave 8b from the reference celestial body has an optical path M due to the sub-reflector displacement. _B → S _B To M _B → S ' _B On the contrary, the optical path length becomes shorter. Therefore, it can be seen that the phase difference between the two has a large error due to the sub-reflector displacement.
[0028]
Thus, the reflector antenna reception phase calibration apparatus according to the invention of the present embodiment passes through the rotationally symmetric main reflector 1, the sub-reflector 2 facing the main reflector 1, and the center of the main reflector 1. Two receiving horns 4a and 4b arranged symmetrically with respect to the main reflector mirror axis, two receivers 5a and 5b for receiving radio waves via the receiving horns 4a and 4b, and two receivers 5a, The digital cross-correlator 6 that detects the phase difference of the radio wave based on the output of 5b, the stay 10 that supports the sub-reflecting mirror 2, and only a predetermined portion of the back surface of the main reflecting mirror 1 to support the main reflecting mirror 1 In the reflector antenna reception phase calibration apparatus having the back structure 11 provided in the plurality of calibration wave sources 3 and the plurality of calibration wave sources 3, the plurality of calibration wave sources 3 are arranged in the vicinity of the stay 10 on the main reflector 1 or on the back surface. Is placed It is arranged in place. Therefore, by installing the calibration wave source 3 at a position not affected by the displacement on the main reflector 1, the amount of displacement of the sub-reflector 2 that is the dominant error is estimated, and the correction value at the time of astronomical observation is calculated. It has an effect that it can be obtained.
[0029]
Embodiment 2. FIG.
FIG. 5 is a schematic configuration diagram of a reflector antenna reception phase calibration apparatus according to Embodiment 2 of the present invention. In FIG. 5, the same reference numerals as those in FIG. 1 of the first embodiment function the same as in FIG. In FIG. 5, a coordinate system O-XYZ is the same as the coordinate system of FIG.
[0030]
In FIG. 5, the first receiving horn 4a and the second receiving horn 4b are located in the XZ plane in the coordinate system shown in FIG. Further, the two calibration wave sources 3 are arranged in the vicinity of the stay 10 on the main reflecting mirror or at the intersection of the back structure 11 at positions N1 and N2 in the YZ plane at positions not displaced by the elevation angle. Further, as in the first embodiment, δrec is considered to be 0 on the assumption that the phase fluctuation amounts of the first receiver 5a and the second receiver 5b are equal.
[0031]
As shown in FIG. 5, when the calibration wave source 3 is arranged in the YZ plane, for example, when considering the calibration wave source 3 arranged at the position of N1, the first reception horn and the second reception horn. Intersection S1 with the sub-reflecting mirror 2 on the way to _A , S1 _B Take the same value only in the sign of the X coordinate due to symmetry. By using such symmetry, the displacement ΔX in the X-axis direction that is asymmetrical displacement with respect to the Z-axis of the sub-reflecting mirror 2 as described in the first embodiment. _S , And the rotation amount Δθ of the sub-reflecting mirror 2 around the axis parallel to the Y axis through the center of the sub-reflecting mirror 2 _YS The following equation holds.
[0032]
[Expression 2]

[0033]
In the above equation, i has values of 1 and 2, and indicates the calibration wave source 3 arranged at the positions of N1 and N2. Ai, Bi, and Ci are expressed by the following equations.
[0034]
[Equation 3]

[0035]
In the above equation, (xi, yi, zi) is an intersection S with the sub-reflecting mirror 2 before displacement from the calibration wave source 3 to the first receiving horn. _iA The coordinates of (n _xi , N _yi , N _zi ) Indicates the unit normal vector of the sub-reflector 2 on these points. Further, gi is an amount obtained from the optical path length difference ΔLoi when the radio wave radiated from the calibration wave source 3 is received by the first receiving horn B, and the intersection S on the sub-reflector 2 from the calibration wave source 3. _iA The unit direction vector of the ray going to _{1, iA} , The unit direction vector after reflection is e _{2, iA} Furthermore, if the optical path length difference ΔLfi when the sub-reflector is not displaced is
[0036]
[Expression 4]

[0037]
It is the quantity represented by. The optical path length difference ΔLfi when the sub-reflecting mirror is not displaced can be obtained using the calculated value. Further, ΔLoi when the mirror surface system is directed in the zenith direction is the displacement ΔX in the X-axis direction of the sub-reflecting mirror. _S , And the rotation amount Δθ of the sub-reflecting mirror 2 around the axis parallel to the Y axis through the center of the sub-reflecting mirror 2 _YS The value does not include a component that is asymmetric with respect to the Z axis, and the value can be used as ΔLfi.
[0038]
Displacement ΔX in the X-axis direction of the sub-reflecting mirror 2 by solving the above equations simultaneously _S , And the rotation amount Δθ of the sub-reflecting mirror 2 around the axis parallel to the Y axis through the center of the sub-reflecting mirror 2 _YS Can be uniquely determined. If the amount of displacement of the sub-reflector can be known, for example, the influence on the phase of the radio wave from the observation object at the time of displacement of the sub-reflector can be calculated by the geometric optical method, so that the amount of correction can be determined.
[0039]
As described above, in the reflector antenna reception phase calibration apparatus according to the invention of the present embodiment, the plurality of calibration wave sources 3 pass through the center of the main reflector on the surface including the two reception horns and the main reflector axis. It is arranged in a vertical plane. Therefore, by installing the calibration wave source 3 at a position not affected by the displacement on the main reflector 1, the amount of displacement of the sub-reflector 2 that is the dominant error is estimated, and the correction value at the time of astronomical observation is calculated. It has an effect that it can be obtained.
[0040]
The digital cross-correlator 6 uniquely determines an asymmetric displacement component with respect to the mirror axis of the sub-reflecting mirror 2 based on the phase signal of the radio wave radiated from the calibration wave source 3. Therefore, only by installing two calibration wave sources 3, the displacement in the X-axis direction of the sub-reflecting mirror 2, which is the dominant error, which is a dominant error, and the Y-axis passing through the center of the sub-reflecting mirror 2. This has the effect that the amount of rotation of the sub-reflecting mirror 2 around the parallel axis can be uniquely determined.
[0041]
Embodiment 3 FIG.
6 is a perspective view of a main part of a reflector antenna reception phase calibration apparatus according to Embodiment 3 of the present invention. In FIG. 6, the same reference numerals as those in FIG. 1 of the first embodiment function the same as in FIG. In FIG. 6, 12 is a receiver mounting plate.
[0042]
In the first and second embodiments described above, the calibration wave source 3 is disposed on the main reflector 1, but in this embodiment, the calibration wave source 3 is provided with receiving horns 4a and 4b. It is installed on the receiving horn mounting plate 12.
[0043]
Thus, the reflector antenna reception phase calibration apparatus according to the invention of the present embodiment passes through the rotationally symmetric main reflector 1, the sub-reflector 2 facing the main reflector 1, and the center of the main reflector 1. Two receiving horns 4a and 4b arranged symmetrically with respect to the main reflector mirror axis, two receivers 5a and 5b for receiving radio waves via the receiving horns 4a and 4b, and two receivers 5a, The digital cross-correlator 6 that detects the phase difference of the radio wave based on the output of 5b, the stay 10 that supports the sub-reflecting mirror 2, and only a predetermined portion of the back surface of the main reflecting mirror 1 to support the main reflecting mirror 1 In the reflector antenna reception phase calibration apparatus having the back structure 11 and the plurality of calibration wave sources 3, the plurality of calibration wave sources are arranged on the reception horn mounting plate 12. Therefore, the main reflector 1 is not affected by deformation due to the elevation angle. Further, in particular, in the second embodiment, the positional relationship between the first receiving horn 4a and the second receiving horn 4b and the calibration wave source 3 is limited, but in this embodiment, on the same plate. Since the first receiving horn 4a and the second receiving horn 4b and the calibration wave source 3 are displaced by gravity due to a change in elevation angle, the first receiving horn 4a and the calibration receiving source 4a are not displaced independently. The positional relationship between the second receiving horn 4b and the calibration wave source 3 has the effect of being displaced while being maintained.
[0044]
Embodiment 4 FIG.
FIG. 7 is a cross-sectional view of a main part of a reflector antenna reception phase calibration apparatus according to Embodiment 4 of the present invention. In FIG. 7, the same reference numerals as those in FIG. 1 of the first embodiment function the same as in FIG.
[0045]
In the above-described first and second embodiments, the calibration wave source 3 is directly attached to the back structure 11 and a radio wave can be emitted by making a hole (through hole) in the main reflecting mirror 1.
[0046]
Thus, the reflector antenna reception phase calibration apparatus according to the invention of the present embodiment passes through the rotationally symmetric main reflector 1, the sub-reflector 2 facing the main reflector 1, and the center of the main reflector 1. Two receiving horns 4a and 4b arranged symmetrically with respect to the main reflector mirror axis, two receivers 5a and 5b for receiving radio waves via the receiving horns 4a and 4b, and two receivers 5a, The digital cross-correlator 6 that detects the phase difference of the radio wave based on the output of 5b, the stay 10 that supports the sub-reflecting mirror 2, and only a predetermined portion of the back surface of the main reflecting mirror 1 to support the main reflecting mirror In the reflector antenna reception phase calibration apparatus having the back structure 11 and the plurality of calibration wave sources 3, the plurality of calibration wave sources are fixed to the back structure 11 and placed at predetermined positions on the main reflector 1. Is emitted from the calibration wave source 3 Through holes for passing the radio wave is provided. Therefore, the influence of the deformation due to the elevation angle of the main reflecting mirror 1 becomes smaller, and the displacement of the calibration wave source 3 that causes an error in estimation can be suppressed.
[0047]
Embodiment 5. FIG.
FIG. 8 is a schematic configuration diagram of a reflector antenna reception phase calibration apparatus according to Embodiment 5 of the present invention. In FIG. 8, the same reference numerals as those in FIG. 1 of the first embodiment function the same as in FIG. In FIG. 8, reference numeral 13 denotes a receiver phase monitor.
[0048]
In the first to fourth embodiments described above, the amount of phase fluctuation by the receivers 5a and 5b is assumed to be the same, and the observation amount is not affected. However, in practice, it is difficult to show the same characteristics. Therefore, the amount of phase fluctuation caused by the receivers 5a and 5b is used as a correction value by monitoring the amount of phase fluctuation caused by the receivers 5a and 5b with the receiver phase monitor 13.
[0049]
As described above, the reflector antenna reception phase calibration device according to the invention of the present embodiment has the receiver phase monitor 13 that monitors the phase fluctuation amount of the radio wave based on the outputs of the two receivers 5a and 5b. Therefore, the phase fluctuations of the receivers 5a and 5b can be separated and used as correction.
[0050]
【The invention's effect】
The reflector antenna reception phase calibration apparatus according to the present invention is arranged symmetrically about the main reflector mirror axis passing through the center of the main reflector, the sub-reflector facing the main reflector, the sub-reflector facing the main reflector Supports two received horns, two receivers that receive radio waves via the receiving horns, a digital cross-correlator that detects the phase difference of radio waves based on the outputs of the two receivers, and a sub-reflector A reflector antenna reception phase calibration apparatus having a stay, a back structure provided only on a predetermined portion of the back surface of the main reflector to support the main reflector, and a plurality of calibration wave sources, The wave source is disposed at a place where the back structure is disposed in the vicinity of the stay or on the back surface of the main reflecting mirror. Therefore, by installing a calibration wave source at a position that is not affected by the displacement on the main reflector, it is possible to estimate the displacement of the sub-reflector, which is the dominant error, and obtain a correction value during astronomical observation. It has the effect of being able to.
[0051]
The reflector antenna reception phase calibration apparatus according to the present invention is rotationally symmetric with respect to the main reflector, the sub-reflector facing the main reflector, and the axis of the main reflector passing through the center of the main reflector. Two receiving horns arranged in the receiver, two receivers for receiving radio waves via the receiving horns, a digital cross-correlator for detecting a phase difference of radio waves based on outputs of the two receivers, and a sub-reflector A reflector antenna reception phase calibration apparatus having a stay supporting the main reflector, a back structure provided only on a predetermined portion of the back surface of the main reflector to support the main reflector, and a plurality of calibration wave sources. The calibration wave source is disposed on the receiving horn mounting plate. Therefore, there is no influence of deformation due to the elevation angle of the main reflecting mirror.
[0052]
The reflector antenna reception phase calibration apparatus according to the present invention is rotationally symmetric with respect to the main reflector, the sub-reflector facing the main reflector, and the axis of the main reflector passing through the center of the main reflector. Two receiving horns arranged in the receiver, two receivers for receiving radio waves via the receiving horns, a digital cross-correlator for detecting a phase difference of radio waves based on outputs of the two receivers, and a sub-reflector A reflector antenna reception phase calibration apparatus having a stay supporting the main reflector, a back structure provided only on a predetermined portion of the back surface of the main reflector to support the main reflector, and a plurality of calibration wave sources. The calibration wave source is fixed to the back structure, and a through-hole for allowing radio waves emitted from the calibration wave source to pass through is provided at a predetermined position of the main reflector. Therefore, the influence of the deformation due to the elevation angle of the main reflecting mirror becomes smaller, and the displacement of the calibration wave source 3 that causes an error in estimation can be suppressed.
[0053]
Further, the plurality of calibration wave sources are arranged in a plane perpendicular to a plane including the two receiving horns and the main mirror axis along the condition and passing through the center of the main mirror. Therefore, by installing a calibration wave source at a position that is not affected by the displacement on the main reflector, it is possible to estimate the displacement of the sub-reflector, which is the dominant error, and obtain a correction value during astronomical observation. It has the effect of being able to.
[0054]
The digital cross-correlator uniquely determines an asymmetric displacement component with respect to the mirror axis of the sub-reflecting mirror based on the phase signal of the radio wave radiated from the calibration wave source. Therefore, the displacement in the X-axis direction of the sub-reflecting mirror, which is the displacement amount of the sub-reflecting mirror, which is a dominant error, and the amount of rotation of the sub-reflecting mirror 2 around the axis passing through the center of the sub-reflecting mirror and parallel to the Y-axis It has the effect that it can be determined uniquely.
[0055]
In addition, a receiver phase monitor is further provided for monitoring the amount of radio wave phase fluctuation based on the outputs of the two receivers. For this reason, the phase variation of the receiver can be separated and used as a correction.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a reflector antenna reception phase calibration apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic diagram of a phase change from a celestial body when the main reflecting mirror is displaced in the Z direction for explaining the first embodiment of the present invention;
FIG. 3 is a schematic diagram of a phase change from a celestial body when the main reflecting mirror has a deflection for explaining the first embodiment of the present invention.
FIG. 4 is a schematic diagram of a phase change from a celestial body when the sub-reflecting mirror is displaced for explaining the first embodiment of the present invention.
FIG. 5 is a schematic configuration diagram of a reflector antenna reception phase calibration apparatus according to a second embodiment of the present invention.
FIG. 6 is a perspective view of a main part of a reflector antenna reception phase calibration apparatus according to a third embodiment of the present invention.
FIG. 7 is a cross-sectional view of a main part of a reflector antenna reception phase calibration apparatus according to a fourth embodiment of the present invention.
FIG. 8 is a schematic configuration diagram of a reflector antenna reception phase calibration apparatus according to a fifth embodiment of the present invention.
FIG. 9 is a conceptual diagram illustrating observation with a conventional two-beam antenna.
FIG. 10 is an explanatory diagram for explaining a conventional method of arranging a calibration wave source.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main reflecting mirror, 1a Rotating symmetrical main reflecting mirror, 1b Main reflecting mirror displaced in Z direction, 1c Deflected main reflecting mirror, 2 Sub reflecting mirror, 2a Displaced sub reflecting mirror, 3 Calibration wave source, 4 Reception horn 4a first receiving horn, 4b second receiving horn, 5 receiver, 5a first receiver, 5b second receiver, 6 digital cross-correlator, 7a observation object, 7b reference object, 8a observation object 8a 'Radio wave from observation object before displacement of main reflector, 8a''Radio wave from observation object after displacement of main reflector, 8b Radio wave from reference object, 8b' Reference object before displacement of main reflector 8b '' Radio wave from the reference celestial body after displacement of the main reflector, 9 Air fluctuation, 10 Stay, 11 Back structure, 12 Receiver horn mounting plate, 13 Receiver phase monitor.

Claims (6)

A rotationally symmetric main reflecting mirror, a sub-reflecting mirror facing the main reflecting mirror, two receiving horns arranged in axial symmetry with respect to a main reflecting mirror axis passing through the center of the main reflecting mirror, and the receiving horn Two receivers for receiving radio waves via the two receivers, a digital cross-correlator for detecting a phase difference of the radio waves based on outputs of the two receivers, a stay for supporting the sub-reflecting mirror, and the main reflecting mirror In a reflector antenna reception phase calibration apparatus having a back structure provided only in a predetermined part of the back surface of the main reflector to support the plurality of calibration wave sources,
The reflector antenna reception phase calibration device, wherein the plurality of calibration wave sources are disposed at a place where the back structure is disposed near or on the back surface of the stay on the main reflector. A rotationally symmetric main reflecting mirror, a sub-reflecting mirror facing the main reflecting mirror, two receiving horns arranged in axial symmetry with respect to a main reflecting mirror axis passing through the center of the main reflecting mirror, and the receiving horn Two receivers for receiving radio waves via the two receivers, a digital cross-correlator for detecting a phase difference of the radio waves based on outputs of the two receivers, a stay for supporting the sub-reflecting mirror, and the main reflecting mirror In a reflector antenna reception phase calibration apparatus having a back structure provided only in a predetermined part of the back surface of the main reflector to support the plurality of calibration wave sources,
The reflector antenna reception phase calibration apparatus, wherein the plurality of calibration wave sources are arranged on a reception horn mounting plate. A rotationally symmetric main reflecting mirror, a sub-reflecting mirror facing the main reflecting mirror, two receiving horns arranged in axial symmetry with respect to a main reflecting mirror axis passing through the center of the main reflecting mirror, and the receiving horn Two receivers for receiving radio waves via the two receivers, a digital cross-correlator for detecting a phase difference of the radio waves based on outputs of the two receivers, a stay for supporting the sub-reflecting mirror, and the main reflecting mirror In a reflector antenna reception phase calibration apparatus having a back structure provided only in a predetermined part of the back surface of the main reflector to support the plurality of calibration wave sources,
The plurality of calibration wave sources are fixed to the back structure, and a through-hole for allowing radio waves emitted from the calibration wave source to pass through is provided at a predetermined position of the main reflecting mirror. Reflector antenna reception phase calibration device. The plurality of calibration wave sources are disposed in a plane perpendicular to a plane including the two receiving horns and the main reflecting mirror axis through the main reflecting mirror center under the above conditions. The reflector antenna reception phase calibration apparatus according to any one of claims 1 to 3. 2. The digital cross-correlator uniquely determines an asymmetric displacement component with respect to the mirror axis of the sub-reflecting mirror based on a phase signal of a radio wave radiated from the calibration wave source. 5. The reflector antenna reception phase calibration device according to any one of 1 to 4. 6. The reflector antenna reception phase calibration device according to claim 1, further comprising a receiver phase monitor that monitors a phase fluctuation amount of the radio wave based on outputs of the two receivers.

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