JP3672239B2 - Radar cross-sectional area measuring method, measuring apparatus therefor, and storage medium recording control program therefor - Google Patents
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Description
【０００１】
【発明の属する技術分野】
この発明は、レーダ断面積の測定方法に関するものである。
【０００２】
【従来の技術】
レーダ断面積(ＲＣＳ：Radar Cross Section)は無限遠方で測定したものとして規定されるため、被測定物から十分遠方で測定する必要がある。通常、被測定物の最大径をＤ、測定波長をλとすると、十分遠方で測定するためには測定距離Ｒは次の(１)式を満たさなければならない。
【０００３】
【数１】
しかし、十分な測定レンジがとれない場合、遠方領域のＲＣＳを求める方法の一つとして、近傍領域での測定値から遠方領域のＲＣＳを推定する方法が提案されている。この範疇に属する従来のＲＣＳ測定として、例えば「１９９９年電子情報通信学会総合大会、Ｂ−１−１０」の論文において近傍領域で測定した散乱界から遠方領域のレーダ断面積を求める方法が提案されている。
【０００５】
図７はこの従来のレーダ断面積の測定方法で定義されている遠方ＲＣＳ推定用の座標系を示す。同図において推定するＲＣＳの方向をＸ軸とし、被測定物のある原点から距離ρの位置に実際に測定する波源および観測点Ｐ(送信アンテナ及び受信アンテナ)を設置する。このとき被測定物のＹ軸方向およびＺ軸方向の最大長をＨｗ、Ｚｗ、測定波長をλとし、測定距離ρは次の(２)式を満たす近傍領域とする。
【０００６】
【数２】
すなわち、被測定物のＹ軸方向の大きさに対しては近傍領域になるが、Ｚ軸方向の大きさに対しては遠方領域になっているものとする。この測定距離において波源および観測点を固定し被測定物をＸＹ面内で回転させ(走査角：φ)散乱電界Ｅｓ(φ)を測定する。ここで散乱電界は電界強度のみでなく位相情報も測定する必要がある。測定範囲がφｗの散乱電界から次の(３)式で散乱体固有の等価散乱係数Ｓｅ(ｙ)を求めることができる。
【０００８】
【数３】
次に被測定物をＹ軸に投影した領域相当ｙｗの等価散乱係数Ｓｅ(ｙ)から次の(４)式で遠方領域におけるＲＣＳ：σを求めることができる。
【００１０】
【数４】
【発明が解決しようとする課題】
従来のＲＣＳ測定方法では等価散乱係数を求めるために、近傍領域の位相情報も含めた散乱電界を必要としていた。しかし、周波数が高くなると精度良く位相を求めることが困難になるという問題点がある。あるいは、位相を精度よく測定するための測定装置が必要になるため、測定系が複雑になるという問題点があった。
【００１２】
この発明は上記の課題を解消するためになされたもので、散乱電界の位相の測定が困難な場合にも遠方でのレーダ断面積を得ることができるレーダ断面積の測定方法、測定装置およびその制御プログラムを記録した記憶媒体を提供することを目的とする。
【００１３】
【課題を解決するための手段】
上記の目的に鑑み、この発明は、レーダ断面積の遠方領域での測定条件から考えて水平方向には大きいが垂直方向には十分小さい被測定物のレーダ断面積の測定方法であって、被測定物からの近傍領域内の上記被測定物からの距離が異なる少なくとも２つの位置で、被測定物を回転走査又は直線移動走査して測定した散乱電界の振幅の測定値を変換して遠方領域におけるレーダ断面積を求めるものであり、上記被測定物からの距離が異なる位置を第１の位置、第２の位置とし、上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定する工程と、第１の位置における位相の初期条件を０に設定する工程と、散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求める工程と、この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求める工程と、この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求める工程と、上記第１と第２の等価散乱係数が差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求める工程と、上記第１と第２の等価散乱係数が差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める工程から繰り返す工程と、を備えたことを特徴とするレーダ断面積の測定方法にある。
【００１４】
また、レーダ断面積の遠方領域での測定条件から考えて水平方向には大きいが垂直方向には十分小さい被測定物のレーダ断面積を求めるレーダ断面積の測定装置であって、上記被測定物を回転走査又は直線移動走査させる走査機構と、上記被測定物に電波を送信する送信アンテナと、上記被測定物からの電波を受信する受信アンテナと、これらの送信および受信アンテナを上記被測定物からの近傍領域内の被測定物からの距離が異なる少なくとも２つの位置に移動させる移動機構と、上記送信および受信アンテナにより上記少なくとも２つの位置で測定した散乱電界の振幅の測定値を変換して遠方領域におけるレーダ断面積を求める制御ユニットと、を備え、上記制御ユニットが、上記被測定物からの距離が異なる位置を第１の位置、第２の位置とし、上記送信および受信アンテナにより上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定する手段と、第１の位置における位相の初期条件を０に設定する手段と、散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求める手段と、この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求める手段と、この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求める手段と、上記第１と第２の等価散乱係数が差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求める手段と、上記第１と第２の等価散乱係数が差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める手段から繰り返す手段と、を備えたことを特徴とするレーダ断面積の測定装置にある。
【００１５】
また、上記制御ユニットが、上記走査機構および移動機構を駆動させ走査および移動を制御する手段をさらに備えたことを特徴とする。
【００１６】
また、レーダ断面積の遠方領域での測定条件から考えて水平方向には大きいが垂直方向には十分小さい被測定物の遠方領域におけるレーダ断面積を、被測定物からの近傍領域内の上記被測定物からの距離が異なる少なくとも２つの位置で、被測定物を回転走査又は直線移動走査して測定した散乱電界の振幅の測定値を変換して求める測定をコンピュータによって制御する制御プログラムを記録した記憶媒体であって、上記被測定物からの距離が異なる位置を第１の位置、第２の位置とし、上記被測定物に電波を送信する送信アンテナと被測定物からの電波を受信する受信アンテナに上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定させる手順と、第１の位置における位相の初期条件を０に設定させる手順と、散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求めさせる手順と、この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求めさせる手順と、この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求めさせる手順と、上記第１と第２の等価散乱係数が差が十分小さいことを判別させる手順と、上記差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求めさせる手順と、上記差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める手順から繰り返させる手順と、を実行させるプログラムを記憶した記憶媒体にある。
【００１７】
また、上記被測定物を回転走査又は直線移動走査させる走査機構を駆動させて、上記被測定物を回転走査又は直線移動走査させる手順と、上記送信および受信アンテナを移動させる移動機構を駆動させて、上記被測定物からの近傍領域内の被測定物からの距離が異なる少なくとも２つの位置に移動させる手順と、を実行させるプログラムをさらに記憶したことを特徴とする。
【００２０】
【発明の実施の形態】
実施の形態１．
図１はこの発明の実施の形態１によるレーダ断面積の測定装置の構成を示す図である。１は被測定物、２は被測定物１を回転走査させる回転機構(走査機構を構成)、３は被測定物１および回転機構２を支持する支持機構である。
【００２１】
４は被測定物１に電波を送信する送信アンテナ、５は被測定物１からの電波を受信する受信アンテナ、６は送受信アンテナ支持機構、７ａは送受信アンテナ移動機構部、７ｂは送受信アンテナ移動用レールである(７ａと７ｂで移動機構を構成)。
【００２２】
被測定物１は回転機構２で任意の角度に回転することができる。また送受および受信アンテナ４、５は送受信アンテナ移動用レール７ｂ上にあり、被測定物１から任意の距離に移動することができる。
【００２３】
１００はこれらの装置の制御を行う例えばコンピュータから構成される制御ユニットで、後述する方法に従って送信および受信アンテナ４、５を駆動して測定した散乱電界から被測定物１の遠方領域におけるレーダ断面積を求める。
【００２４】
図２はこの実施の形態における測定方法を説明する座標系を示す。１は被測定物、４、５は送信および受信アンテナを示す。座標系および被測定物１を回転する走査方法は従来例に示した方法と同様とする。従って、上記(２)〜(４)式が成立する。さらに、等価散乱係数Ｓｅ(ｙ)から近傍領域の距離ρ、走査角φにおける散乱電界Ｅｓ(φ)は次の(５)式で求めることができる。
【００２５】
【数５】
ここで積分範囲ｙｗは被測定物１のＹ軸への投影領域相当である。制御ユニット１００はこの座標系において図２に示すように異なる距離ρ１、ρ２に送受信アンテナ４、５を設置してそれぞれにおいて散乱電界Ｅ１、Ｅ２を測定し、これらの測定値から図３に示すフローチャートの手順で遠方ＲＣＳを求める。次にこれらの各手順について説明する。
【００２７】
必要とするデータは上述した距離ρ１、ρ２における散乱電界の測定値であるが、位相成分は不明で電界強度のみ測定する。またそれぞれの電界強度を振幅Ａ１、Ａ２とする(ステップＳ１)。
【００２８】
距離ρ１での散乱電界の位相成分は不明であるが、初期条件として位相：Ｐ１が０であると仮定する(ステップＳ２)。
【００２９】
距離ρ１における散乱電界が振幅Ａ１、位相Ｐ１であると仮定し、(２)式に従い等価散乱係数Ｓｅ’(ｙ)を求める(ステップＳ３)。
【００３０】
ステップＳ３で求めた等価散乱係数Ｓｅ’(ｙ)から、(２)式に従い距離ρ２における散乱電界を求め、その振幅をＡ２’、位相をＰ２’とする(ステップＳ４)。
【００３１】
ステップＳ４で得られた位相Ｐ２’、最初の測定で得られた振幅Ａ２を距離ρ２における散乱電界とし、(２)式に従い等価散乱係数Ｓｅ’’(ｙ)を求める(ステップＳ５)。
【００３２】
ステップＳ３、ステップＳ５でそれぞれ得られた等価散乱係数Ｓｅ’(ｙ)、Ｓｅ’’(ｙ)の差が十分小さいか否か判定する。Ｓｅ’(ｙ)、Ｓｅ’’(ｙ)は位置ｙにより異なるため、例えば被測定物１のｙ軸投影領域相当内に等間隔にｍ点の参照点｛ｙｉ ｜ ｉ＝１、・・・、ｍ｝をとり、これらの参照点でのＳｅ’(ｙ)、Ｓｅ’’(ｙ)の誤差平均が微小量δ以下であるか否か判定すればよい。
【００３３】
【数６】
上記(６)式を満たす場合には十分収束していると判定しステップＳ９に進み、これらの等価散乱係数から遠方ＲＣＳを計算する。上記(６)式を満たさない場合には次のステップ７に進む(ステップＳ６)。
【００３５】
ステップＳ５で求めた等価散乱係数Ｓｅ’’(ｙ)から(５)式に従い距離ρ１における散乱電界を求め、その振幅をＡ１’’、位相をＰ１’’とする(ステップＳ７)。
【００３６】
距離ρ１における位相Ｐ１をステップＳ７で得られたＰ１’’で置き換え、ステップＳ３から繰り返す(ステップＳ８)。
【００３７】
ステップＳ６で収束条件が満たされている場合には等価散乱係数Ｓｅ’(ｙ)あるいはＳｅ’’(ｙ)で(４)式に従い遠方領域におけるＲＣＳを求める(ステップＳ９)。
【００３８】
上述したステップＳ４〜ステップＳ８を繰り返し行うことにより、初期値の散乱電界として位相情報がなくても、真の等価散乱係数に近いものを得ることができ、遠方でのＲＣＳを求めることができる。また本実施の形態では２つの測定距離で測定した散乱電界の測定値を用いたが、３つ以上の位置で測定した散乱電界に対して同様の処理を行ってもよい。
【００３９】
以上のように本実施の形態によれば、周波数が高いこと等で散乱電界の位相の測定が困難な場合にも遠方でのＲＣＳを得ることができる。
また、位相測定機構のない簡易な測定系、装置を実現できるという効果がある。
また、直接遠方でのＲＣＳを測定する測定系と比べてコンパクトな測定系、装置を実現することができる。
【００４０】
なお、図４に示すように高精度に散乱電界強度を測定するため、被測定物１と送信および受信アンテナ４、５間に電波吸収体９を設置し高精度に散乱電界強度を測定できるようにしてもよい。電波吸収体９が設置されているため、地面反射などの不要波の影響を取り除くことができ高精度に散乱電界を測定できるため、高精度に遠方でのＲＣＳを求めることができるという効果がある。
【００４１】
実施の形態２．
図５はこの発明の実施の形態２によるレーダ断面積の測定装置の構成を示す図である。図５において上記実施の形態１と同一もしくは相当部分は同一符号で示す。８ａは被測定物移動機構部、８ｂは被測定物移動用レールである(８ａと８ｂで走査機構を構成)。上記実施の形態１では被測定物１を回転走査していたがこの実施の形態では直線移動走査させている。
【００４２】
被測定物１は被測定物移動用レール８ｂ上にあり、任意の位置に直線的に移動することができる。また送信および受信アンテナ４、５も送受信アンテナ移動用レール７上にあり、被測定物から任意の距離に移動することができる。
【００４３】
図６はこの実施の形態における測定方法を説明する座標系を示す。１は被測定物、４、５は送信および受信アンテナを示す。本実施の形態においても図６に示すように被測定物から距離ρ１、ρ２の位置において散乱電界を測定するが、走査方法は直線走査とする。被測定物１をＹ軸方向に移動させ、その移動量をｙ’とする。この走査方法において距離ρで測定した散乱電界Ｅｓ(ｙ’)から等価散乱係数Ｓｅ(ｙ)を求める関係式は次の(７)式で与えられる。
【００４４】
【数７】
また、等価散乱係数Ｓｅ(ｙ)から距離ρ、走査量ｙ’で測定した散乱電界Ｅｓ(ｙ’)は次の(８)式で与えられる。
【００４６】
【数８】
本実施の形態において距離ρ１、ρ２における散乱電界の振幅のみの測定値から遠方でのＲＣＳを求める手順は、前実施の形態における数３、数５の関係式を数７、数８に置き換えて図２に示す方法で同様に行えばよい。
【００４８】
本実施の形態においても、周波数が高いこと等で散乱電界の位相の測定が困難な場合にも遠方でのＲＣＳを得ることができる。
また、位相測定機構のない簡易な測定系、装置を実現できるという効果がある。
また、直接遠方でのＲＣＳを測定する測定系と比べてコンパクトな測定系、装置を実現することができる。
【００４９】
なおこの実施の形態においても、図４に示したように高精度に散乱電界強度を測定するため、被測定物１と送信および受信アンテナ４、５間に電波吸収体９を設置し高精度に散乱電界強度を測定できるようにしてもよく、同様な効果がある。
【００５０】
【発明の効果】
以上のようにこの発明によれば、レーダ断面積の遠方領域での測定条件から考えて水平方向には大きいが垂直方向には十分小さい被測定物のレーダ断面積の測定方法であって、被測定物からの近傍領域内の上記被測定物からの距離が異なる少なくとも２つの位置で、被測定物を回転走査又は直線移動走査して測定した散乱電界の振幅の測定値を変換して遠方領域におけるレーダ断面積を求めることを特徴とするレーダ断面積の測定方法としたので、周波数が高いこと等で散乱電界の位相の測定が困難な場合にも遠方でのＲＣＳを得ることができる。
【００５１】
また、上記被測定物からの距離が短いものから第１の位置、第２の位置とし、上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定する工程と、第１の位置における位相の初期条件を０に設定する工程と、散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求める工程と、この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求める工程と、この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求める工程と、上記第１と第２の等価散乱係数が差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求める工程と、上記第１と第２の等価散乱係数が差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める工程から繰り返す工程と、を備えたので、周波数が高いこと等で散乱電界の位相の測定が困難な場合にも遠方でのＲＣＳを得ることができ、また、位相測定機構のない簡易な測定系を実現でき、また、直接遠方でのＲＣＳを測定する測定系と比べてコンパクトな測定系を実現することができる。
【００５２】
また、レーダ断面積の遠方領域での測定条件から考えて水平方向には大きいが垂直方向には十分小さい被測定物のレーダ断面積を求めるレーダ断面積の測定装置であって、上記被測定物を回転走査又は直線移動走査させる走査機構と、上記被測定物に電波を送信する送信アンテナと、上記被測定物からの電波を受信する受信アンテナと、これらの送信および受信アンテナを上記被測定物からの近傍領域内の被測定物からの距離が異なる少なくとも２つの位置に移動させる移動機構と、上記送信および受信アンテナにより上記少なくとも２つの位置で測定した散乱電界の振幅の測定値を変換して遠方領域におけるレーダ断面積を求める制御ユニットと、を備えたことを特徴とするレーダ断面積の測定装置としたので、周波数が高いこと等で散乱電界の位相の測定が困難な場合にも遠方でのＲＣＳを得ることができる。
【００５３】
また、上記制御ユニットが、上記２つの位置を被測定物からの距離が短いものから第１の位置、第２の位置とし、上記送信および受信アンテナにより上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定する手段と、第１の位置における位相の初期条件を０に設定する手段と、散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求める手段と、この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求める手段と、この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求める手段と、上記第１と第２の等価散乱係数が差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求める手段と、上記第１と第２の等価散乱係数が差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める手段から繰り返す手段と、を備えたので、周波数が高いこと等で散乱電界の位相の測定が困難な場合にも遠方でのＲＣＳを得ることができ、また、位相測定機構のない簡易な装置にすることができ、さらに直接遠方でのＲＣＳを測定する測定系と比べてコンパクトな装置とすることができる。
【００５４】
また、上記制御ユニットが、上記走査機構および移動機構を駆動させ走査および移動を制御する手段をさらに備えることにより、測定全体の総合的な制御が行える。
【００５５】
また、レーダ断面積の遠方領域での測定条件から考えて水平方向には大きいが垂直方向には十分小さい被測定物の遠方領域におけるレーダ断面積を、被測定物からの近傍領域内の上記被測定物からの距離が異なる少なくとも２つの位置で、被測定物を回転走査又は直線移動走査して測定した散乱電界の振幅の測定値を変換して求める測定をコンピュータによって制御する制御プログラムを記録した記憶媒体であって、上記被測定物からの距離が短いものから第１の位置、第２の位置とし、上記被測定物に電波を送信する送信アンテナと被測定物からの電波を受信する受信アンテナに上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定させる手順と、第１の位置における位相の初期条件を０に設定させる手順と、散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求めさせる手順と、この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求めさせる手順と、この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求めさせる手順と、上記第１と第２の等価散乱係数が差が十分小さいことを判別させる手順と、上記差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求めさせる手順と、上記差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める手順から繰り返させる手順と、を実行させるプログラムを記憶した記憶媒体としたので、周波数が高いこと等で散乱電界の位相の測定が困難な場合にも遠方でのＲＣＳを得ることができ、位相測定機構のない簡易な装置を実現でき、また直接遠方でのＲＣＳを測定する測定系と比べてコンパクトな装置を実現することができる。
【００５６】
また、上記被測定物を回転走査又は直線移動走査させる走査機構を駆動させて、上記被測定物を回転走査又は直線移動走査させる手順と、上記送信および受信アンテナを移動させる移動機構を駆動させて、上記被測定物からの近傍領域内の被測定物からの距離が異なる少なくとも２つの位置に移動させる手順と、を実行させるプログラムをさらに記憶したものとしたので、測定全体の総合的な制御が行える装置を実現できる。
【図面の簡単な説明】
【図１】 この発明の実施の形態１によるレーダ断面積の測定装置の構成を示す図である。
【図２】 この発明の実施の形態１における測定方法を説明する座標系を示す。
【図３】 この発明の実施の形態１によるレーダ断面積の測定装置の測定動作を説明するためのフローチャートである。
【図４】 この発明の実施の形態１によるレーダ断面積の測定装置の変形例を示す図である。
【図５】 この発明の実施の形態２によるレーダ断面積の測定装置の構成を示す図である。
【図６】 この発明の実施の形態２における測定方法を説明する座標系を示す。
【図７】 従来のレーダ断面積の測定方法で定義されている遠方ＲＣＳ推定用の座標系を示す図である。
【符号の説明】
１ 被測定物、２ 回転機構、３ 支持機構、４ 送信アンテナ、５ 受信アンテナ、６ 送受信アンテナ支持機構、７ａ 送受信アンテナ移動機構部、７ｂ送受信アンテナ移動用レール、８ａ 被測定物移動機構部、８ｂ 被測定物移動用レール、１００ 制御ユニット。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring a radar cross section.
[0002]
[Prior art]
Since the radar cross section (RCS) is defined as being measured at infinity, it must be measured sufficiently far from the object to be measured. Usually, when the maximum diameter of the object to be measured is D and the measurement wavelength is λ, the measurement distance R must satisfy the following equation (1) in order to measure sufficiently far away.
[0003]
[Expression 1]
However, when a sufficient measurement range cannot be taken, as a method for obtaining the RCS of the far region, a method of estimating the RCS of the far region from the measurement values in the near region has been proposed. As a conventional RCS measurement belonging to this category, for example, a method for obtaining a radar cross section in a far region from a scattered field measured in a near region is proposed in a paper of “1999 Annual Conference of the Institute of Electronics, Information and Communication Engineers, B-1-10”. ing.
[0005]
FIG. 7 shows a coordinate system for estimating a remote RCS defined by this conventional radar cross-sectional area measurement method. The direction of RCS estimated in the figure is the X axis, and a wave source and an observation point P (transmitting antenna and receiving antenna) that are actually measured are installed at a distance ρ from the origin of the object to be measured. At this time, the maximum length of the DUT in the Y-axis direction and the Z-axis direction is Hw, Zw, the measurement wavelength is λ, and the measurement distance ρ is a nearby region that satisfies the following equation (2).
[0006]
[Expression 2]
That is, it is assumed that the area to be measured is in the vicinity area with respect to the size in the Y-axis direction, but is in the distance area with respect to the size in the Z-axis direction. At this measurement distance, the wave source and the observation point are fixed, the object to be measured is rotated in the XY plane (scanning angle: φ), and the scattered electric field Es (φ) is measured. Here, it is necessary to measure not only the electric field strength but also phase information of the scattered electric field. The equivalent scattering coefficient Se (y) specific to the scatterer can be obtained from the scattered electric field having the measurement range φw by the following equation (3).
[0008]
[Equation 3]
Next, RCS: σ in the far region can be obtained from the equivalent scattering coefficient Se (y) of the region corresponding to yw obtained by projecting the object to be measured on the Y axis by the following equation (4).
[0010]
[Expression 4]
[Problems to be solved by the invention]
In the conventional RCS measurement method, a scattered electric field including phase information in the vicinity region is required to obtain an equivalent scattering coefficient. However, there is a problem that it becomes difficult to obtain the phase with high accuracy as the frequency increases. Alternatively, since a measuring device for measuring the phase with high accuracy is required, there is a problem that the measuring system becomes complicated.
[0012]
The present invention has been made in order to solve the above-described problems. A radar cross-sectional area measuring method, a measuring apparatus, and a measuring apparatus that can obtain a radar cross-sectional area at a distance even when measurement of the phase of the scattered electric field is difficult are provided. It is an object to provide a storage medium in which a control program is recorded.
[0013]
[Means for Solving the Problems]
In view of the above object, the present invention is a method for measuring a radar cross section of an object to be measured that is large in the horizontal direction but sufficiently small in the vertical direction in view of the measurement conditions in the far region of the radar cross section. Distant region by converting the measured value of the amplitude of the scattered electric field measured by rotating or linearly scanning the object to be measured at at least two positions in the vicinity area from the object to be measured at different distances from the object to be measured. The position where the distance from the object to be measured is different is defined as the first position and the second position, and the intensity of the scattered electric field at each of the first and second positions is scattered. A step of measuring the amplitude of the electric field, a step of setting the initial condition of the phase at the first position to 0, and the first equivalent scattering at the first position with the amplitude and phase at which the scattered electric field is obtained as 0 The process for obtaining the coefficient and this The step of obtaining the amplitude and phase of the scattered electric field at the second position from the first equivalent scattering coefficient, the phase in the obtained scattered electric field at the second position, and the scattered electric field at the second position obtained first. A step of obtaining the second equivalent scattering coefficient from the scattered electric field having the amplitude in FIG. 3 and a radar in a far region from the first or second equivalent scattering coefficient when the difference between the first and second equivalent scattering coefficients is sufficiently small. When the difference between the first and second equivalent scattering coefficients is not sufficiently small, a scattered electric field at the first position is obtained from the second equivalent scattering coefficient when the difference between the first and second equivalent scattering coefficients is not sufficiently small. A radar cross-sectional area measuring method comprising: a step of repeating from the step of obtaining the first equivalent scattering coefficient again by replacing with the phase at the position .
[0014]
A radar cross-sectional area measuring device for obtaining a radar cross-sectional area of an object to be measured that is large in the horizontal direction but sufficiently small in the vertical direction in consideration of the measurement conditions in the far region of the radar cross-sectional area, A scanning mechanism that rotates or linearly scans, a transmission antenna that transmits radio waves to the object to be measured, a reception antenna that receives radio waves from the object to be measured, and the transmission and reception antennas for the object to be measured A moving mechanism for moving to at least two positions having different distances from the object to be measured in the vicinity region from the distance, and converting the measured value of the scattered electric field amplitude measured at the at least two positions by the transmitting and receiving antennas. A control unit for obtaining a radar cross-sectional area in a far region, wherein the control unit defines a position at a different distance from the object to be measured as a first position, a second position And means for measuring the intensity of the scattered electric field at the first and second positions as the amplitude of the scattered electric field by the transmitting and receiving antennas, and setting the initial phase condition at the first position to zero. Means for obtaining the first equivalent scattering coefficient at the first position by setting the amplitude and phase at which the scattered electric field is obtained to zero, and the amplitude of the scattered electric field at the second position from the first equivalent scattering coefficient. And a means for obtaining a second equivalent scattering coefficient from a phase of the obtained scattered electric field at the second position and an amplitude of the scattered electric field at the second position obtained first. And means for obtaining a radar cross section in a distant region from the first or second equivalent scattering coefficient when the difference between the first and second equivalent scattering coefficients is sufficiently small, and the first and second equivalent scattering coefficients The difference in coefficient is ten If not, the means for obtaining the scattered electric field at the first position from the second equivalent scattering coefficient, replacing the phase obtained therefrom with the phase at the first position, and repeating the means from the means for obtaining the first equivalent scattering coefficient again. And a radar cross section measuring device characterized by comprising:
[0015]
The control unit may further include means for driving the scanning mechanism and the moving mechanism to control scanning and movement.
[0016]
In addition, considering the measurement conditions in the far area of the radar cross section, the radar cross section in the far area of the measured object that is large in the horizontal direction but small enough in the vertical direction is the above-mentioned area in the vicinity area from the measured object. A control program for controlling the measurement obtained by converting the measured value of the amplitude of the scattered electric field measured by rotating or linearly scanning the object to be measured at at least two positions at different distances from the object to be measured was recorded. A storage medium, wherein a position at a different distance from the object to be measured is a first position and a second position, and a transmission antenna that transmits electric waves to the object to be measured and reception that receives electric waves from the object to be measured A procedure for causing the antenna to measure the intensity of the scattered electric field at each of the first and second positions as the amplitude of the scattered electric field, and a procedure for setting the initial phase condition at the first position to zero The procedure for obtaining the first equivalent scattering coefficient at the first position by setting the amplitude and phase at which the scattered electric field is obtained to 0, and the amplitude of the scattered electric field at the second position from the first equivalent scattering coefficient, The second equivalent scattering coefficient is obtained from the procedure for obtaining the phase, the phase in the scattered electric field at the obtained second position, and the scattered electric field as the amplitude in the scattered electric field at the first obtained second position. A procedure for determining that the difference between the first and second equivalent scattering coefficients is sufficiently small, and a radar cross-sectional area in a far region from the first or second equivalent scattering coefficient when the difference is sufficiently small. When the difference is not sufficiently small, the scattered electric field at the first position is obtained from the second equivalent scattering coefficient, and the phase obtained from the phase is replaced with the phase at the first position. etc And instructions to repeat steps for obtaining the scattering coefficient, the storage medium storing a program for executing the certain.
[0017]
In addition, by driving a scanning mechanism for rotating or linearly scanning the object to be measured, a procedure for rotating or linearly scanning the object to be measured and a moving mechanism for moving the transmitting and receiving antennas are driven. And a program for executing a procedure for moving to at least two positions having different distances from the object to be measured in a vicinity region from the object to be measured.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a diagram showing a configuration of a radar cross-sectional area measuring apparatus according to Embodiment 1 of the present invention. Reference numeral 1 denotes an object to be measured, 2 denotes a rotation mechanism (a scanning mechanism) that rotates and scans the object 1 to be measured, and 3 denotes a support mechanism that supports the object 1 and the
[0021]
4 is a transmitting antenna that transmits radio waves to the
[0022]
The DUT 1 can be rotated at an arbitrary angle by the
[0023]
[0024]
FIG. 2 shows a coordinate system for explaining the measurement method in this embodiment. Reference numeral 1 denotes a device under test, and 4 and 5 denote transmission and reception antennas. A scanning method for rotating the coordinate system and the DUT 1 is the same as the method shown in the conventional example. Therefore, the above equations (2) to (4) are established. Furthermore, from the equivalent scattering coefficient Se (y), the distance ρ in the vicinity region and the scattered electric field Es (φ) at the scanning angle φ can be obtained by the following equation (5).
[0025]
[Equation 5]
Here, the integration range yw corresponds to the projection area of the DUT 1 on the Y axis. As shown in FIG. 2, the
[0027]
The necessary data are the measured values of the scattered electric field at the distances ρ1 and ρ2 described above, but the phase component is unknown and only the electric field strength is measured. Further, the electric field strengths are set as amplitudes A1 and A2 (step S1).
[0028]
The phase component of the scattered electric field at the distance ρ1 is unknown, but it is assumed that the phase: P1 is 0 as an initial condition (step S2).
[0029]
Assuming that the scattered electric field at the distance ρ1 has the amplitude A1 and the phase P1, the equivalent scattering coefficient Se ′ (y) is obtained according to the equation (2) (step S3).
[0030]
From the equivalent scattering coefficient Se ′ (y) obtained in step S3, the scattered electric field at the distance ρ2 is obtained according to the equation (2), the amplitude is A2 ′, and the phase is P2 ′ (step S4).
[0031]
The phase P2 ′ obtained in step S4 and the amplitude A2 obtained in the first measurement are used as the scattered electric field at the distance ρ2, and the equivalent scattering coefficient Se ″ (y) is obtained according to the equation (2) (step S5).
[0032]
It is determined whether or not the difference between the equivalent scattering coefficients Se ′ (y) and Se ″ (y) obtained in steps S3 and S5 is sufficiently small. Since Se ′ (y) and Se ″ (y) differ depending on the position y, for example, m reference points {yi | i = 1,... , M} to determine whether the average error of Se ′ (y) and Se ″ (y) at these reference points is less than or equal to the minute amount δ.
[0033]
[Formula 6]
If the above equation (6) is satisfied, it is determined that the convergence is sufficient, and the process proceeds to step S9 to calculate the far RCS from these equivalent scattering coefficients. If the above equation (6) is not satisfied, the process proceeds to the next step 7 (step S6).
[0035]
From the equivalent scattering coefficient Se ″ (y) obtained in step S5, a scattered electric field at a distance ρ1 is obtained according to the equation (5), the amplitude is A1 ″, and the phase is P1 ″ (step S7).
[0036]
The phase P1 at the distance ρ1 is replaced with P1 ″ obtained at step S7, and the process is repeated from step S3 (step S8).
[0037]
If the convergence condition is satisfied in step S6, the RCS in the far region is obtained from the equivalent scattering coefficient Se ′ (y) or Se ″ (y) according to the equation (4) (step S9).
[0038]
By repeating Steps S4 to S8 described above, even if there is no phase information as the initial value of the scattered electric field, a value close to the true equivalent scattering coefficient can be obtained, and the RCS at a distance can be obtained. In the present embodiment, the measurement value of the scattered electric field measured at two measurement distances is used, but the same processing may be performed on the scattered electric field measured at three or more positions.
[0039]
As described above, according to the present embodiment, a remote RCS can be obtained even when it is difficult to measure the phase of the scattered electric field due to a high frequency or the like.
In addition, there is an effect that a simple measurement system and apparatus without a phase measurement mechanism can be realized.
In addition, a compact measurement system and apparatus can be realized as compared with a measurement system that directly measures RCS at a distance.
[0040]
In order to measure the scattered electric field strength with high accuracy as shown in FIG. 4, a radio wave absorber 9 is installed between the DUT 1 and the transmitting and receiving
[0041]
FIG. 5 is a diagram showing the configuration of a radar cross-sectional area measuring apparatus according to
[0042]
The DUT 1 is on the DUT moving rail 8b and can move linearly to an arbitrary position. The transmitting and receiving
[0043]
FIG. 6 shows a coordinate system for explaining the measurement method in this embodiment. Reference numeral 1 denotes a device under test, and 4 and 5 denote transmission and reception antennas. In this embodiment, as shown in FIG. 6, the scattered electric field is measured at positions ρ1 and ρ2 from the object to be measured, and the scanning method is linear scanning. The DUT 1 is moved in the Y-axis direction, and the amount of movement is y ′. In this scanning method, the relational expression for obtaining the equivalent scattering coefficient Se (y) from the scattered electric field Es (y ′) measured at the distance ρ is given by the following expression (7).
[0044]
[Expression 7]
Further, the scattered electric field Es (y ′) measured from the equivalent scattering coefficient Se (y) at the distance ρ and the scanning amount y ′ is given by the following equation (8).
[0046]
[Equation 8]
In the present embodiment, the procedure for obtaining the RCS in the distance from the measured values of only the amplitudes of the scattered electric fields at the distances ρ1 and ρ2 is obtained by replacing the relational expressions of
[0048]
In the present embodiment as well, a remote RCS can be obtained even when it is difficult to measure the phase of the scattered electric field due to a high frequency or the like.
In addition, there is an effect that a simple measurement system and apparatus without a phase measurement mechanism can be realized.
In addition, a compact measurement system and apparatus can be realized as compared with a measurement system that directly measures RCS at a distance.
[0049]
Also in this embodiment, as shown in FIG. 4, in order to measure the scattered electric field strength with high accuracy, a radio wave absorber 9 is installed between the DUT 1 and the transmitting and receiving
[0050]
【The invention's effect】
As described above, according to the present invention, there is provided a method for measuring a radar cross section of an object to be measured that is large in the horizontal direction but sufficiently small in the vertical direction in view of the measurement conditions in the far region of the radar cross section. Distant region by converting the measured value of the amplitude of the scattered electric field measured by rotating or linearly scanning the object to be measured at at least two positions in the vicinity area from the object to be measured at different distances from the object to be measured. Since the radar cross-sectional area measurement method is characterized in that the radar cross-section area is obtained at Rf, even when it is difficult to measure the phase of the scattered electric field due to the high frequency, it is possible to obtain the RCS at a distance.
[0051]
A step of measuring the intensity of the scattered electric field at each of the first and second positions as the amplitude of the scattered electric field from the shortest distance from the object to be measured to the first position and the second position; A step of setting the initial phase condition at the first position to 0, a step of obtaining the first equivalent scattering coefficient at the first position by setting the amplitude and phase at which the scattered electric field is obtained to 0, A step of obtaining the amplitude and phase of the scattered electric field at the second position from the equivalent scattering coefficient of 1, the phase of the obtained scattered electric field at the second position, and the scattered electric field at the second position obtained first. The step of obtaining the second equivalent scattering coefficient from the scattering electric field having the amplitude and the radar disconnection in the far region from the first or second equivalent scattering coefficient when the difference between the first and second equivalent scattering coefficients is sufficiently small. A step of obtaining an area; When the difference in the second equivalent scattering coefficient is not sufficiently small, the scattered electric field at the first position is obtained from the second equivalent scattering coefficient, and the phase obtained therefrom is replaced with the phase at the first position, and the first equivalent scattering coefficient is obtained again. From the step of obtaining the equivalent scattering coefficient of the RCS, it is possible to obtain a remote RCS even when it is difficult to measure the phase of the scattered electric field due to the high frequency, etc. It is possible to realize a simple measurement system without any noise, and it is possible to realize a compact measurement system as compared with a measurement system that directly measures RCS at a distance.
[0052]
A radar cross-sectional area measuring device for obtaining a radar cross-sectional area of an object to be measured that is large in the horizontal direction but sufficiently small in the vertical direction in consideration of the measurement conditions in the far region of the radar cross-sectional area, A scanning mechanism that rotates or linearly scans, a transmission antenna that transmits radio waves to the object to be measured, a reception antenna that receives radio waves from the object to be measured, and the transmission and reception antennas for the object to be measured A moving mechanism for moving to at least two positions having different distances from the object to be measured in the vicinity region from the distance, and converting the measured value of the scattered electric field amplitude measured at the at least two positions by the transmitting and receiving antennas. A radar cross-sectional area measuring device characterized by comprising a control unit for obtaining a radar cross-sectional area in a distant region. Can also when the measurement of the field phase difficult to obtain the RCS in the distance.
[0053]
Further, the control unit changes the two positions from the one having a short distance from the object to be measured to the first position and the second position, and the transmission and reception antennas at the first and second positions, respectively. Means for measuring the intensity of the scattered electric field as the amplitude of the scattered electric field, means for setting the initial condition of the phase at the first position to zero, and the amplitude and phase at which the scattered electric field was obtained as zero. Means for determining the first equivalent scattering coefficient at the first position, means for determining the amplitude and phase of the scattered electric field at the second position from the first equivalent scattering coefficient, and the phase of the determined scattered electric field at the second position. Means for obtaining the second equivalent scattering coefficient from the scattered electric field having the amplitude in the scattered electric field at the second position obtained first, and when the difference between the first and second equivalent scattering coefficients is sufficiently small, First or second equivalent A means for obtaining a radar cross-sectional area in a distant region from a disturbance coefficient, and a scattered electric field at a first position from the second equivalent scattering coefficient when the difference between the first and second equivalent scattering coefficients is not sufficiently small; Means for replacing the phase obtained from this with the phase at the first position and repeating from the means for obtaining the first equivalent scattering coefficient again, so that it is difficult to measure the phase of the scattered electric field due to the high frequency, etc. Even in this case, it is possible to obtain an RCS at a distant location, a simple device without a phase measurement mechanism, and a compact device as compared with a measurement system that directly measures an RCS at a distant location. it can.
[0054]
Further, the control unit further includes means for controlling the scanning and movement by driving the scanning mechanism and the moving mechanism, whereby comprehensive control of the entire measurement can be performed.
[0055]
In addition, considering the measurement conditions in the far area of the radar cross section, the radar cross section in the far area of the measured object that is large in the horizontal direction but small enough in the vertical direction is the above-mentioned area in the vicinity area from the measured object. A control program for controlling the measurement obtained by converting the measured value of the amplitude of the scattered electric field measured by rotating or linearly scanning the object to be measured at at least two positions at different distances from the object to be measured was recorded. A storage medium that has a short distance from the object to be measured, the first position and the second position, a transmission antenna that transmits electric waves to the object to be measured, and reception that receives electric waves from the object to be measured A procedure for causing the antenna to measure the intensity of the scattered electric field at each of the first and second positions as the amplitude of the scattered electric field, and a procedure for setting the initial phase condition at the first position to zero The procedure for obtaining the first equivalent scattering coefficient at the first position by setting the amplitude and phase at which the scattered electric field is obtained to 0, and the amplitude of the scattered electric field at the second position from the first equivalent scattering coefficient, The second equivalent scattering coefficient is obtained from the procedure for obtaining the phase, the phase in the scattered electric field at the obtained second position, and the scattered electric field as the amplitude in the scattered electric field at the first obtained second position. A procedure for determining that the difference between the first and second equivalent scattering coefficients is sufficiently small, and a radar cross-sectional area in a far region from the first or second equivalent scattering coefficient when the difference is sufficiently small. When the difference is not sufficiently small, the scattered electric field at the first position is obtained from the second equivalent scattering coefficient, and the phase obtained from the phase is replaced with the phase at the first position. etc Since the storage medium stores the program for executing the procedure for repeating the procedure for obtaining the scattering coefficient, the RCS can be obtained at a distance even when the phase of the scattered electric field is difficult due to the high frequency. Therefore, a simple apparatus without a phase measurement mechanism can be realized, and a more compact apparatus can be realized as compared with a measurement system that directly measures RCS at a remote location.
[0056]
In addition, by driving a scanning mechanism for rotating or linearly scanning the object to be measured, a procedure for rotating or linearly scanning the object to be measured and a moving mechanism for moving the transmitting and receiving antennas are driven. In addition, a program for executing a procedure for moving to at least two positions having different distances from the object to be measured in the vicinity region from the object to be measured is further stored. A device that can be implemented is realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a radar cross-sectional area measuring apparatus according to Embodiment 1 of the present invention.
FIG. 2 shows a coordinate system for explaining a measurement method according to Embodiment 1 of the present invention.
FIG. 3 is a flowchart for explaining a measurement operation of the radar cross-section measuring apparatus according to the first embodiment of the present invention.
FIG. 4 is a diagram showing a modification of the radar cross-sectional area measuring apparatus according to Embodiment 1 of the present invention.
FIG. 5 is a diagram showing a configuration of a radar cross-section measuring apparatus according to
FIG. 6 shows a coordinate system for explaining a measurement method according to
FIG. 7 is a diagram showing a coordinate system for remote RCS estimation defined by a conventional radar cross-sectional area measurement method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Measured object, 2 Rotating mechanism, 3 Support mechanism, 4 Transmitting antenna, 5 Receiving antenna, 6 Transmitting / receiving antenna supporting mechanism, 7a Transmitting / receiving antenna moving mechanism part, 7b Rail for transmitting / receiving antenna moving, 8a Measured object moving mechanism part, 8b Measuring object moving rail, 100 control unit.
Claims (5)
上記被測定物からの距離が異なる位置を第１の位置、第２の位置とし、
上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定する工程と、
第１の位置における位相の初期条件を０に設定する工程と、
散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求める工程と、
この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求める工程と、
この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求める工程と、
上記第１と第２の等価散乱係数が差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求める工程と、
上記第１と第２の等価散乱係数が差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める工程から繰り返す工程と、
を備えたことを特徴とするレーダ断面積の測定方法。A method for measuring the radar cross section of an object to be measured that is large in the horizontal direction but sufficiently small in the vertical direction in consideration of the measurement conditions in the far area of the radar cross section, and in the vicinity of the object to be measured. The radar cross-sectional area in the far region is obtained by converting the measured value of the amplitude of the scattered electric field measured by rotating or linearly scanning the object to be measured at at least two positions at different distances from the object to be measured .
The position where the distance from the measurement object is different is the first position, the second position,
Measuring the intensity of the scattered electric field at each of the first and second positions as the amplitude of the scattered electric field;
Setting the initial condition of the phase at the first position to 0;
Obtaining the first equivalent scattering coefficient at the first position by setting the amplitude and phase from which the scattered electric field is obtained to 0;
Obtaining the amplitude and phase of the scattered electric field at the second position from the first equivalent scattering coefficient;
Obtaining a second equivalent scattering coefficient from the phase of the obtained scattered electric field at the second position and the scattered electric field as the amplitude of the scattered electric field at the first obtained second position;
Obtaining a radar cross section in a distant region from the first or second equivalent scattering coefficient when the difference between the first and second equivalent scattering coefficients is sufficiently small;
When the difference between the first and second equivalent scattering coefficients is not sufficiently small, the scattered electric field at the first position is obtained from the second equivalent scattering coefficient, and the phase obtained from this is replaced with the phase at the first position again. Repeating from the step of obtaining the first equivalent scattering coefficient;
Measurement method of radar cross-sectional area, comprising the.
上記被測定物を回転走査又は直線移動走査させる走査機構と、
上記被測定物に電波を送信する送信アンテナと、
上記被測定物からの電波を受信する受信アンテナと、
これらの送信および受信アンテナを上記被測定物からの近傍領域内の被測定物からの距離が異なる少なくとも２つの位置に移動させる移動機構と、
上記送信および受信アンテナにより上記少なくとも２つの位置で測定した散乱電界の振幅の測定値を変換して遠方領域におけるレーダ断面積を求める制御ユニットと、
を備え、
上記制御ユニットが、上記被測定物からの距離が異なる位置を第１の位置、第２の位置とし、
上記送信および受信アンテナにより上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定する手段と、
第１の位置における位相の初期条件を０に設定する手段と、
散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求める手段と、
この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求める手段と、
この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求める手段と、
上記第１と第２の等価散乱係数が差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求める手段と、
上記第１と第２の等価散乱係数が差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める手段から繰り返す手段と、
を備えたことを特徴とするレーダ断面積の測定装置。A radar cross-section measuring device that obtains a radar cross-section of an object to be measured that is large in the horizontal direction but sufficiently small in the vertical direction in consideration of the measurement conditions in the far region of the radar cross-section,
A scanning mechanism for rotating or linearly scanning the object to be measured;
A transmitting antenna for transmitting radio waves to the object to be measured;
A receiving antenna for receiving radio waves from the object to be measured;
A moving mechanism for moving these transmitting and receiving antennas to at least two positions having different distances from the object to be measured in the vicinity region from the object to be measured;
A control unit for converting a measured value of the amplitude of the scattered electric field measured at the at least two positions by the transmitting and receiving antennas to obtain a radar cross section in a distant region;
Equipped with a,
The control unit has a position at which the distance from the object to be measured is different as a first position and a second position,
Means for measuring the intensity of the scattered electric field at the first and second positions by the transmitting and receiving antennas as the amplitude of the scattered electric field;
Means for setting the initial condition of the phase at the first position to zero;
Means for determining the first equivalent scattering coefficient at the first position by setting the amplitude and phase from which the scattered electric field is determined to 0;
Means for determining the amplitude and phase of the scattered electric field at the second position from the first equivalent scattering coefficient;
Means for obtaining a second equivalent scattering coefficient from the phase of the obtained scattered electric field at the second position and the scattered electric field as the amplitude of the scattered electric field at the first obtained second position;
Means for obtaining a radar cross-sectional area in a far region from the first or second equivalent scattering coefficient when the difference between the first and second equivalent scattering coefficients is sufficiently small;
When the difference between the first and second equivalent scattering coefficients is not sufficiently small, the scattered electric field at the first position is obtained from the second equivalent scattering coefficient, and the phase obtained from this is replaced with the phase at the first position again. Repeating from the means for obtaining the first equivalent scattering coefficient;
Measuring device of the radar cross-sectional area, comprising the.
上記被測定物からの距離が異なる位置を第１の位置、第２の位置とし、上記被測定物に電波を送信する送信アンテナと被測定物からの電波を受信する受信アンテナに上記第１および第２のそれぞれの位置での散乱電界の強度を散乱電界の振幅として測定させる手順と、
第１の位置における位相の初期条件を０に設定させる手順と、
散乱電界が求められた上記振幅、位相を０として第１の位置での第１の等価散乱係数を求めさせる手順と、
この第１の等価散乱係数から第２の位置の散乱電界の振幅と位相を求めさせる手順と、
この求められた第２の位置の散乱電界における位相、最初に求められた第２の位置での散乱電界における振幅とする散乱電界から第２の等価散乱係数を求めさせる手順と、
上記第１と第２の等価散乱係数が差が十分小さいことを判別させる手順と、
上記差が十分小さい場合に上記第１又は第２の等価散乱係数から遠方領域におけるレーダ断面積を求めさせる手順と、
上記差が十分小さくない場合に上記第２の等価散乱係数から第１の位置における散乱電界を求め、これから求まる位相を第１の位置における位相に置き換えて再度、上記第１の等価散乱係数を求める手順から繰り返させる手順と、
を実行させるプログラムを記憶した記憶媒体。Considering the measurement conditions of the radar cross-sectional area in the far area, the radar cross section in the far area of the object to be measured is large in the horizontal direction but sufficiently small in the vertical direction. Storage medium storing a control program for controlling a measurement obtained by converting the measured value of the amplitude of the scattered electric field measured by rotating or linearly scanning the object to be measured at at least two positions different from each other Because
The first position and the second position are positions at different distances from the object to be measured, and the first and second antennas are used as a transmitting antenna that transmits radio waves to the object to be measured and a receiving antenna that receives radio waves from the object to be measured. A procedure for measuring the intensity of the scattered electric field at each second position as the amplitude of the scattered electric field;
A procedure for setting the initial phase condition at the first position to 0;
A procedure for obtaining the first equivalent scattering coefficient at the first position by setting the amplitude and phase from which the scattered electric field is obtained to 0;
A procedure for determining the amplitude and phase of the scattered electric field at the second position from the first equivalent scattering coefficient;
A procedure for obtaining a second equivalent scattering coefficient from the phase of the obtained scattered electric field at the second position and the scattered electric field as the amplitude of the scattered electric field at the first obtained second position;
A procedure for determining that the difference between the first and second equivalent scattering coefficients is sufficiently small;
A procedure for obtaining a radar cross section in a far region from the first or second equivalent scattering coefficient when the difference is sufficiently small;
When the difference is not sufficiently small, the scattered electric field at the first position is obtained from the second equivalent scattering coefficient, and the phase obtained from the first position is replaced with the phase at the first position to obtain the first equivalent scattering coefficient again. A procedure to be repeated from the procedure,
A storage medium storing a program for executing the program.
上記送信および受信アンテナを移動させる移動機構を駆動させて、上記被測定物からの近傍領域内の被測定物からの距離が異なる少なくとも２つの位置に移動させる手順と、
を実行させるプログラムをさらに記憶したことを特徴とする請求項４に記載の記憶媒体。A procedure of driving a scanning mechanism for rotating or linearly scanning the object to be measured, and rotating or linearly scanning the object to be measured;
A procedure for driving the moving mechanism for moving the transmitting and receiving antennas to move the moving mechanism to at least two positions having different distances from the object to be measured in the vicinity region from the object to be measured;
The storage medium according to claim 4 , further storing a program for executing.
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