JP3697522B2 - Interference source earth station location method - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、地球局が送信した電波が、運用中の静止通信衛星に対して干渉を与えているとき、その地球局の地図上での位置を、監視衛星を用いて特定する方法を提供する。
【０００２】
【従来の技術】
静止軌道上で運用中の静止通信衛星に対して、地球局が送信した電波が干渉を与えると、通信回線に障害が生じ、最悪の場合は回線断に至る。このことは衛星通信において大きな潜在的問題である。電波干渉が発生したとき、その対策をとるためには、問題の地球局が地図上のどこにあるかを知るのが効果的である。干渉源地球局の位置を特定するための方法として、干渉源地球局から干渉を受ける静止通信衛星が２つあり、それら２つの静止通信衛星からの電波を受信する地球局がある場合に、それぞれの静止通信衛星が干渉源地球局から干渉電波を受ける遅延差を用いて干渉源地球局の地図上の位置を特定する方法がある（例えば、非特許文献１参照）。
【０００３】
【非特許文献１】
ウィリアム・ダブリュ．・スミス，ジュニア（WILLIAM W. SMITH,JR）、ポール・ジー．・ステッフス（PAUL G. STEFFES），衛星干渉評定システムのための時間遅延技術（Time Delay Techniques for Satellite Interference Location System），米国電気電子技術者協会 航空宇宙電子システム報告（IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS）Ｖｏｌ．ＡＥＳ−２５，Ｎｏ．２ １９８９年３月，ｐ．２２４−ｐ．２３１
【０００４】
上述した従来技術である干渉源地球局の位置特定方法を以下に説明する。図６において、地球Ｔの地表面にある地球局Ｘが送信した電波が、静止軌道Ｏ上にある静止通信衛星Ａに干渉を与えているとする。また、静止通信衛星Ａの付近には別の静止通信衛星Ｂがあって、静止通信衛星Ａ，Ｂは同じ周波数帯で運用しているとする。
【０００５】
このとき、静止通信衛星Ｂもまた低レベルながら、地球局Ｘからの干渉電波を受ける。なぜなら、一般に送信アンテナはメインローブのほかにサイドローブをもつため、静止通信衛星Ａと静止通信衛星Ｂが地球局Ｘのアンテナサイドローブの広がり範囲内にあれば、静止通信衛星Ｂにも電波が入感するのである。従って、干渉源地球局である地球局Ｘからの電波を、静止通信衛星Ａと静止通信衛星Ｂの下り回線を通じて共に地球局Ｇにおいて受信したならば、地球局Ｘの電波が静止通信衛星Ａを介して地球局Ｇに到達するのに要した時間と、地球教Ｘの電波が静止通信衛星Ｂを介して地球局Ｇに到達するのに要した時間との差（遅延時間）を、地球局Ｇで測定し得る。
【０００６】
ここで、静止通信衛星Ａ，Ｂの位置が分かっているとすると、上記のように測定した遅延時間により等価的に、静止通信衛星Ａから地球局Ｘに至る距離ＡＸと、静止通信衛星Ｂから地球局Ｘに至る距離ＢＸとの差ＡＸ−ＢＸを測定したとみなしてよい。このように測定した距離差に基づいて、地図上における地球局Ｘの位置を特定するのである。
【０００７】
【発明が解決しようとする課題】
しかしながら、従来の干渉源地球局の位置特定方法には、次のような欠点があった。まず、静止通信衛星Ａと同じ周波数帯で運用する静止通信衛星Ｂが軌道上に存在していても、静止通信衛星Ａと静止通信衛星Ｂの間隔が地球局Ｘのアンテナサイドローブの広がりに比べて大きかったならば、静止通信衛星Ｂには地球局Ｘの電波が入感しないから、上記の距離差の測定は不可能である。つまり、静止衛星軌道上における静止通信衛星の配置状況と、干渉源地球局の位置および電波の送信特性と、干渉源地球局の位置特定を行う地球局の位置、といった諸条件が満たされていなければ、上記の方法は適用できないのである。
【０００８】
また、上記の距離差測定ができた場合には、その距離差を満たす地表面上（地図上）の点の集合として、一本の曲線（ほぼ直線と看做しうる場合も含む）が規定され、この地図上に描いた曲線（以下、この曲線を解曲線と称する。）上のどこかに、地球局Ｘが位置すると判断できるものの、地図上の一点として地球局Ｘの位置を特定することは出来ない。なお、上記の解曲線の現れ方は、干渉源地球局に対する静止通信衛星Ａと静止通信衛星Ｂの位置に依存する。なかでも特に、図７に示すように、地球局Ｘから見上げて観察したとき、静止通信衛星Ａと静止通信衛星Ｂを結ぶ線分がどの方向を指すかということに依存する。
【０００９】
さて、静止静止通信衛星といえども実際には、地球Ｔに対してわずかに動いており、静止軌道Ｏから微動することとなる。たとえば、１回目の距離差の測定を行ったとき、静止通信衛星Ａと静止通信衛星Ｂは、図７において、それぞれＡ1とＢ1にあり、これに対応して地図上に解曲線が１つ描かれたとする。時間が経過した後に、２回目の距離差の測定を行うと、静止通信衛星Ａと静止通信衛星Ｂの位置は、図７で、例えばＡ2とＢ2のようにそれぞれ変わったとすると、それに応じて地図上には１つ目の解曲線と異なる解曲線が描かれる。
【００１０】
よって、原理上は、２つの解曲線の交点上に地球局Ｘがあると特定されるのであるが、実際には、図７においてＡ1からＡ2への静止通信衛星Ａの動きと、Ｂ1からＢ2への静止通信衛星Ｂの動きは、共に地心から見て０．１度程度を超え得ないのに対し、静止通信衛星Ａと静止通信衛星Ｂの間隔は数度（典型的には４度）あるため、線分Ａ1Ｂ1と線分Ａ2Ｂ2の指す方向はわずかな違いしかもたないから、上記の２つの解曲線は、たとえ異なっていてもその交わりかたは平行に近い。すなわち、地球局Ｘの位置を地図上の一点に特定するのは事実上不可能であり、実質的には、１つの解曲線上に干渉源地球局（地球局Ｘ）があることを知るに止まり、その位置を狭く絞り込むのは困難である。
【００１１】
以上のように、従来の干渉源地球局の位置特定方法では、以下のような欠点があったのである。▲１▼：干渉源地球局の位置特定は、行い得る場合と行い得ない場合があり、それは軌道上の静止通信衛星の配置状況等に依存する。▲２▼：たとえ干渉源地球局の位置特定を行い得たとしても、その特定は１次元的にとどまり、２次元的な位置特定は難しい。
【００１２】
そこで、本発明は、静止軌道上の衛星配置状況等に依存することなく、干渉源地球局の位置特定を好適に行い得る干渉源地球局の位置特定方法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】
上記の課題を解決するために、請求項１に係る発明は、静止軌道上の静止通信衛星に干渉を与える電波を発する地球局である干渉源地球局の位置を、地上の他の地球局である監視地球局により特定する干渉源地球局の位置特定方法であって、静止軌道より高度が低い円軌道上を地球と逆向きに周回し、干渉源地球局からの干渉電波を受ける被干渉衛星が使用する周波数とは異なる周波数で下り回線の通信を行う監視衛星を置き、上記監視衛星が、被干渉衛星の真下を通過する過程で、少なくとも２回以上、干渉源地球局から到来した電波を中継して地球方向へ送り返し、上記監視衛星からの下り回線と被干渉衛星からの下り回線を共に監視地球局によって受信する毎に、干渉源地球局が発した電波が被干渉衛星を介して監視地球局に至るに要した時間と、干渉源地球局が発した電波が監視衛星を介して監視地球局に至るに要した時間の差を測定し、その時間の差の測定に基づいて、被干渉衛星から干渉源地球局に至る距離と、監視衛星から干渉源地球局に至る距離の差を求め、その求めた距離の差に基づいて、干渉源地球局が存在する可能性のある点の集合である解曲線を地図上に引き、上記監視衛星からの下り回線と被干渉衛星からの下り回線を共に監視地球局によって受信する毎に引かれた複数の解曲線の交点として、干渉源地球局の位置を特定するようにしたことを特徴とする。
【００１４】
また、請求項２に係る発明は、上記請求項１に記載の干渉源地球局の位置特定方法において、上記監視衛星の軌道は、赤道面から傾斜させた円軌道であることを特徴とする。
【００１５】
また、請求項３に係る発明は、上記請求項２に記載の干渉源地球局の位置特定方法において、第１監視衛星が赤道面から傾斜する円軌道を周回するときに、赤道面から十分に離れていて、干渉源地球局と第１監視衛星と被干渉衛星が一直線に並ばない範囲である稼働領域が全周の半分以上となるように第１監視衛星の軌道の傾斜角を設定し、上記第１監視衛星による稼働領域とならない範囲が稼働領域となるように周回軌道を設定した第２監視衛星を設けるようにしたことを特徴とする。
【００１６】
【発明の実施の形態】
次に、添付図面に基づいて、本発明に係る干渉源地球局の位置特定方法の実施形態を詳細に説明する。
【００１７】
図１において、静止軌道Ｏにある静止通信衛星Ａが、地球局Ｘ（干渉源地球局）からの干渉電波を受けている被干渉衛星であるとする。この図は、自転する地球に紙面が貼り付いているものとして、北極を見下ろすように描いている。よって図上で地球局Ｘの位置は動かず、静止通信衛星もＡ点にあってほとんど動かない。
【００１８】
また、静止軌道Ｏの内側の円軌道上に、監視用の通信衛星として監視衛星Ｍを置き、監視衛星Ｍは地球の回転と逆向きに軌道Ｐを周回させる。一例として、監視衛星Ｍの軌道は静止軌道（約３６０００ｋｍ）より２０００ｋｍ下にあるとすると、監視衛星Ｍは静止通信衛星Ａの真下を約１１時間３０分に１回の割合で通過する。静止通信衛星Ａの真下付近を監視衛星Ｍが通過しているとき、地球局Ｘが静止通信衛星Ａに向けて発した電波は監視衛星Ｍにも到達する。監視衛星Ｍは、静止通信衛星Ａと同様に、地球から送られてきた電波を中継して地球方向へ送り返す。ただし、監視衛星Ｍの下り回線は、静止通信衛星Ａと異なる周波数を用いるものとし、監視衛星Ｍからの電波と静止通信衛星Ａからの電波を識別して受信できるようにしておく。
【００１９】
このとき、静止通信衛星Ａからの中継電波と監視衛星Ｍの下り回線を共に地球局Ｇで受信したならば、地球局Ｘの電波が静止通信衛星Ａを介して地球局Ｇに達するに要した時間と、地球局Ｘの電波が監視衛星Ｍを介して地球局Ｇに到達するに要した時間との差を測定し得る。よって、地球局Ｘからの干渉電波受信時における静止通信衛星Ａと監視衛星Ｍの位置が分かっているとすると、上記の時間差測定により、等価的に静止通信衛星Ａから地球局Ｘに至る距離ＡＸと、監視衛星Ｍから地球局Ｘに至る距離ＭＸとの差ＡＸ−ＭＸが測定される。この測定を、以下では単に距離差測定と称する。
【００２０】
図２は、監視衛星Ｍが静止通信衛星Ａの真下付近を通過中のとき、それを赤道面Ｅに沿って観察したもので、地球Ｔと静止通信衛星Ａは紙面に固定されているが、監視衛星Ｍは紙面をよぎって手前に出てくるように動く。そのとき地球局Ｘから静止通信衛星Ａ，監視衛星Ｍを見上げて観察すると、図３のようになって、監視衛星Ｍは静止通信衛星Ａの下側を、図中の左側から右側へ、順にＭ1，Ｍ2，Ｍ3のように通過する。監視衛星Ｍが、Ｍ1とＭ3の位置にある時に、それぞれ、上述による距離差測定を行うと、地図上に２つの解曲線が引かれる。線分Ｍ1Ａと線分Ｍ3Ａが指す方向は大きく異なることから、地図上に引いた２つの解曲線も大きな角をもって互いに交わることとなり、その結果、地球局Ｘの位置を１点に特定することが可能となる。実際には、監視衛星ＭがＭ1からＭ2を経てＭ3に至るまでの間に多数回の距離差測定を行い得るので、多数の解曲線が共通に交わる点として地球局Ｘの位置特定をさらに絞り込むことが可能である。
【００２１】
上述したように、静止軌道Ｏの真下約２０００ｋｍで地球の時点方向と逆向きの円軌道Ｐを有する監視衛星Ｍを用いた干渉源地球局の位置特定方法によれば、静止通信衛星Ａが静止軌道Ｏ上のどこにあろうとも、静止通信衛星Ａの真下を監視衛星Ｍが約１１時間半ごとに必ず通過するので、干渉源地球局の位置特定をおこなうための地球局Ｇに相当する地球局を、適切に選んだ複数の場所に設けたならば、静止軌道上のどの静止通信衛星に電波干渉が発生しようとも、干渉源地球局の位置特定を実行することが必ず可能であり、その実行までの待ち時間は１１時間半を越えることはない。無論、監視衛星Ｍを同一軌道上に複数配置しておけば、干渉源地球局の位置特定までの待ち時間を一層短縮できる。
【００２２】
したがって、本実施形態に係る干渉源地球局の位置特定方法によれば、静止通信衛星の配置状況等に起因して干渉源地球局の位置特定が不可能となる事態は起きないし、干渉源地球局の位置を複数の解曲線の交点として特定できる。すなわち、本実施形態に係る干渉源地球局の位置特定方法では、従来の干渉源地球局の位置特定方法に内在していた欠点▲１▼，▲２▼を一挙に解決できるのである。しかも、一定の待ち時間の間に干渉源地球局の位置を必ず特定できることは、干渉の迅速な除去につながり、それは衛星通信回線の信頼性を保つ上で効果が大きい。
【００２３】
以上の説明では、本発明方法の適用に際して、静止軌道上での静止通信衛星Ａの位置と、地球上での地球局Ｘの位置は、共に任意でよいとしたが、これには唯一の例外がある。それは地球局Ｘが赤道上に位置する場合である。このような場合には、監視衛星Ｍが軌道Ｐ上を進んでいくと、ある時点で地球局Ｘ、監視衛星Ｍ、静止通信衛星Ａが一直線上に並ぶ。それを図３に即していえば、静止通信衛星Ａは監視衛星Ｍの通過飛跡の上にある。すると、線分Ｍ1Ａ，Ｍ2Ａ，Ｍ3Ａ等の指す方向は皆ひとしくなることから、解曲線も大きく交わらず、従来の方法における欠点▲２▼と類似の状況を生じるため、地球局Ｘの位置を１点に特定することが難しい。
【００２４】
しかしながら、本発明方法では、従来の方法とは異なり、このような状況が生じたことで、地球局Ｘが赤道上に位置することを特定できる効果をもつ。従って、地図上の１点への位置特定は全く不可能ではない。すなわち、静止軌道よりも内側の円軌道を地球の自転方向と逆向きに回る監視衛星を用いるときは、干渉源地球局が赤道上に位置するときに位置特定の誤差が増すという限定条件のもとで、常に地球局の位置特定が可能である。
【００２５】
とはいえ、上記の実施形態では、干渉源地球局が赤道上に位置していた場合に、位置特定の誤差範囲が特に南北方向に広がることを免れない。このような不都合が生じる原因は、上述のとおり地球局Ｘ、監視衛星Ｍ、静止通信衛星Ａが一直線上に並び得ることにある。そこで、このような不都合をも解消することができる干渉源地球局の位置特定方法の実施形態を以下に説明する。
【００２６】
図４に示すのは、監視衛星Ｍの軌道Ｐを赤道面Ｅから小さな角度θだけ傾斜させたもので、監視衛星Ｍが赤道面Ｅから離れるときの離れ方が、監視衛星Ｍが軌道Ｐ上を進むにつれて周期的に変化することとなる。初めに、監視衛星Ｍが赤道面から最も離れたＭａにあったとすると、それは監視衛星Ｍが進むにつれてＭｂを経て、Ｍｃに達した所で赤道面をよぎり、軌道半周回の後には初めの離れ方を南北逆転したＭｄに達する。その後は反対向きの動きをたどり、軌道半周回の後に初めのＭａに戻る。
【００２７】
さて、このように軌道Ｐを一周するあいだ、監視衛星Ｍは静止軌道上にある色々な静止通信衛星の真下付近を通過する。いま、ある静止通信衛星Ａの真下付近を通過したとき、赤道面からの監視衛星Ｍの離れ方は、例えばＭｂであったとしよう。線分Ａ−Ｍｂを延長した直線をＬとすると、Ｌは地球と交差しない。これは、地球の子午線を通る面内に監視衛星Ｍと静止通信衛星Ａが位置する場合であっても、干渉源地球局Ｘ−監視衛星Ｍ−静止通信衛星Ａが一直線に並ばないことを意味する。すなわち、任意の場所にある地球局Ｘが静止通信衛星Ａに干渉を与えた場合、地球局Ｘの位置特定が可能である。このように、監視衛星Ｍが赤道面Ｅから十分に離れていて、干渉源地球局Ｘと監視衛星Ｍと静止通信衛星Ａが一直線に並ばない範囲であれば、地上にある地球局Ｘの位置特定は絶対に可能となる。
【００２８】
なお、監視衛星Ｍの軌道Ｐを赤道面Ｅから傾けても、Ｌ（線分Ａ−Ｍを延長した直線）が地球と交差する範囲においては、干渉源地球局Ｘ−監視衛星Ｍ−静止通信衛星Ａが一直線に並ぶ可能性があるため、上述した第１実施形態と同様に、干渉源地球局Ｘの位置特定が困難ケースが生ずる。すなわち、監視衛星Ｍの軌道面からの離れ方に依って、Ｌが地球と交差しない範囲（干渉源地球局の位置特定が絶対に可能な稼働領域）と、Ｌが地球と交差する範囲（干渉源地球局の位置特定が困難になるケースが生ずる領域）とに区分けできる。
【００２９】
図５（ａ）は、第１監視衛星Ｍが軌道を一周するなかで、赤道面からの離れ方が十分となる領域（Ｌが地球と交差しない範囲）を示すもので、例えば、第１監視衛星Ｍが赤道面から離れている距離に応じて、２つの稼働領域１ａ，１ｂが得られることを示す。本図では、紙面は地球に貼り付けず、慣性空間に立場をおいて遠い所から北極を見下ろしている。もし、稼働領域１ａで第１監視衛星Ｍが赤道面から北側へ離れているなら、稼働領域１ｂでは第１監視衛星Ｍは赤道面の南側へ離れる。また、傾斜角度θが大きいほど、稼働領域が軌道の一周回のなかに占める割合が増す。例として、監視衛星Ｍの軌道Ｐが静止軌道Ｏの２０００ｋｍ下にあるとすると、傾斜角度θを０．６度にすれば、稼働領域１ａと稼働領域１ｂを合わせた割合は軌道全周の２分の１を超える。
【００３０】
ここで、もう１機の監視衛星である第２監視衛星Ｍ′を配備し、その軌道Ｐ′の形状および傾斜の角度は第１監視衛星Ｍと同じにする（図５（ｂ）参照）。そして、第２監視衛星Ｍ′の稼働領域２ａ，２ｂは、Ｍの稼働領域１ａ，１ｂと相補的になるように配置する。それには、第１監視衛星Ｍが赤道面をよぎる点と、第２監視衛星Ｍ′が赤道面をよぎる点とが、地球Ｔの中心から見て９０度異なるように配置すればよい。こうすれば、地球Ｔ上の任意の場所にある地球局が静止軌道Ｏ上にある静止通信衛星に干渉を与えたとき、第１監視衛星Ｍもしくは第２監視衛星Ｍ′のどちらか一方の稼働領域でカバーされているので、干渉源地球局の位置特定は必ず可能となる。
【００３１】
このように、２機の監視衛星を用いるならば、任意の地球局が任意の静止通信衛星に電波干渉を与えたとき、常に地球局の位置特定が可能である。また、本実施形態のように、監視衛星Ｍと監視衛星Ｍ′の稼働領域を相補的に設けた場合は、地球上のどの位置に干渉源地球局があっても、位置特定を実行するまでの待ち時間は１１時間半を越えない。なお、監視衛星Ｍの軌跡Ｐおよび監視衛星Ｍ′の軌跡Ｐ′が赤道面Ｅと成す傾斜角θを大きくすれば、夫々の稼働領域が広がるので、監視衛星Ｍと監視衛星Ｍ′の両衛星にカバーされる領域が広がることとなり、両衛星の稼働領域に含まれる領域に干渉源地球局があった場合には、その位置特定までの待ち時間を一層短縮できるという利点がある。
【００３２】
また、上述した２つの実施形態では、監視衛星の軌道を、静止軌道より２０００ｋｍ低い円軌道に設定して説明したが、監視衛星の軌道は、特にこの高度に限定されるものではない。しかしながら、監視衛星と静止衛星は、互いに逆向きに飛行してすれ違うから、安全を保つために十分な高度差をとる必要がある。その一方で、干渉源地球局→静止通信衛星→監視地球局の伝搬路で着信した信号と、干渉源地球局→監視衛星→監視地球局の伝搬路で着信した信号の時間差検出に際して、両伝搬路の距離が大きく異なるほど、より複雑な信号処理が必要になるという問題があり、この点からは、監視衛星と静止衛星の高度差は少ないほうが良いのである。このような二律背反する条件を共に満たす高度差として、上記実施形態にて述べた２０００ｋｍの高度差は望ましいものである。
【００３３】
なお、地球の自転に逆行する監視衛星の軌道を、静止軌道の外側に設けても、干渉源地球局の位置特定は可能であるから、技術的には問題ないものの、現実的には、監視衛星の軌道を静止軌道の内側に設定せざるを得ない。なぜなら、一般的に衛星が静止軌道上において寿命を終えるに先だって、その衛星が漂流して運用中の静止衛星に危険を及ぼすことを未然に避けるため、静止軌道の外側へその衛星を移動させる規約となっているからである。実際、静止軌道の外側には使用済みとなった元静止衛星が広い高度範囲に亘って漂流しているので、その中に逆行する監視衛星を置くのは危険である。
【００３４】
【発明の効果】
以上説明したように、請求項１に係る干渉源地球局の位置特定方法によれば、静止軌道より高度が低い円軌道上を地球と逆向きに周回する監視衛星を置き、この監視衛星が被干渉衛星の真下を通過する過程で、少なくとも２回以上、干渉源地球局から到来した電波を中継して地球方向へ送り返し、監視衛星からの下り回線と被干渉衛星からの下り回線を共に監視地球局によって受信する毎に解曲線が得られ、それら複数の解曲線の交点として干渉源地球局の位置を特定するものとしたので、静止通信衛星の配置状況等に起因して干渉源地球局の位置特定が不可能となる事態は起きないし、干渉源地球局の位置を複数の解曲線の交点として特定できる。すなわち、本発明に係る干渉源地球局の位置特定方法では、従来の干渉源地球局の位置特定方法に内在していた欠点▲１▼，▲２▼を一挙に解決できるのである。しかも、一定の待ち時間の間に干渉源地球局の位置を必ず特定できることは、干渉の迅速な除去につながり、それは衛星通信回線の信頼性を保つ上で効果が大きい。
【００３５】
また、請求項２に係る干渉源地球局の位置特定方法によれば、監視衛星の軌道を、赤道面から傾斜させた円軌道としたので、赤道面上の干渉源地球局の位置特定が困難となる状態を抑制できる。
【００３６】
また、請求項３に係る干渉源地球局の位置特定方法によれば、第１監視衛星が赤道面から傾斜する円軌道を周回するときに、赤道面から十分に離れていて、干渉源地球局と第１監視衛星と被干渉衛星が一直線に並ばない範囲である稼働領域が全周の半分以上となるように第１監視衛星の軌道の傾斜角を設定し、上記第１監視衛星による稼働領域とならない範囲が稼働領域となるように周回軌道を設定した第２監視衛星を設けるようにしたので、地上の全領域で干渉源地球局の位置特定を必ず行うことが可能となる。
【図面の簡単な説明】
【図１】第１実施形態に係る干渉源地球局の位置特定方法における、静止軌道Ｏの静止通信衛星Ａと軌道Ｐの監視衛星Ｍと、地上の地球局Ｘと地球局Ｇにおける電波の送受信関係を示す説明図である。
【図２】赤道面に沿って観察した、第１実施形態における、静止通信衛星Ａと監視衛星Ｍと地球局Ｘの位置関係を示す説明図である。
【図３】地球局Ｘから見上げて観察した静止通信衛星Ａと監視衛星Ｍの位置関係を示す説明図である。
【図４】赤道面に沿って観察した、第２実施形態における、静止通信衛星Ａと監視衛星Ｍと地球局Ｘの位置関係を示す説明図である。
【図５】（ａ）赤道面からθだけ傾斜させた軌道Ｐを有する監視衛星Ｍの稼働領域を示す説明図である。（ｂ）赤道面からθだけ傾斜させた軌道Ｐ′を有する監視衛星Ｍ′の稼働領域を示す説明図である。
【図６】従来の干渉源地球局の位置特定方法における、静止軌道上の静止通信衛星Ａと静止通信衛星Ｂと、地上の地球局Ｘと地球局Ｇにおける電波の送受信関係を示す説明図である。
【図７】静止軌道Ｏに対する静止通信衛星Ａと静止通信衛星Ｂの位置変化の説明図である。
【符号の説明】
Ａ 静止通信衛星
Ｍ，Ｍ′ 監視衛星
Ｘ 地球局（干渉源地球局）
Ｇ 地球局（監視地球局）
Ｏ 静止軌道
Ｐ，Ｐ′ 監視衛星Ｍ，Ｍ′の軌道
１ａ，１ｂ 監視衛星Ｍの稼働領域
２ａ，２ｂ 監視衛星Ｍ′の稼働領域[0001]
BACKGROUND OF THE INVENTION
The present invention provides a method for specifying a position of a earth station on a map using a monitoring satellite when radio waves transmitted from the earth station interfere with a stationary communication satellite in operation. .
[0002]
[Prior art]
If radio waves transmitted by the earth station interfere with a geostationary communication satellite operating in geostationary orbit, the communication line will be damaged, and in the worst case, the line will be disconnected. This is a major potential problem in satellite communications. In order to take measures against radio wave interference, it is effective to know where the problem earth station is on the map. When there are two geostationary communication satellites that receive interference from the interfering source earth station, and there are earth stations that receive radio waves from these two geostationary communication satellites, There is a method of specifying the position of the interference source earth station on the map by using a delay difference in which the geostationary communication satellites receive interference radio waves from the interference source earth station (see Non-Patent Document 1, for example).
[0003]
[Non-Patent Document 1]
William W.・ Smith, Junior (WILLIAM W. SMITH, JR), Paul G.・ PAUL G. STEFFES, Time Delay Techniques for Satellite Interference Location System, American Institute of Electrical and Electronics Engineers Aerospace Electronic Systems Report (IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS) Vol. AES-25, No. 2 March 1989, p. 224-p. 231
[0004]
A method for specifying the position of the interference source earth station, which is the above-described prior art, will be described below. In FIG. 6, it is assumed that the radio wave transmitted by the earth station X on the ground surface of the earth T interferes with the geostationary communication satellite A on the geostationary orbit O. Further, it is assumed that there is another geostationary communication satellite B near the geostationary communication satellite A, and the geostationary communication satellites A and B operate in the same frequency band.
[0005]
At this time, the geostationary communication satellite B also receives an interference radio wave from the earth station X while being at a low level. Because the transmission antenna generally has side lobes in addition to the main lobe, if the geostationary communication satellite A and the geostationary communication satellite B are within the extension range of the antenna side lobe of the earth station X, radio waves are also transmitted to the geostationary communication satellite B. I feel it. Therefore, if the radio wave from the earth station X which is the interference source earth station is received at the earth station G through the downlinks of the geostationary communication satellite A and the geostationary communication satellite B, the radio wave of the earth station X is transmitted to the geostationary communication satellite A. The difference (delay time) between the time required to reach the earth station G via the earth and the time required for the radio wave of Earth X to reach the earth station G via the geostationary communication satellite B G can be measured.
[0006]
If the positions of the geostationary communication satellites A and B are known, the distance AX from the geostationary communication satellite A to the earth station X and the geostationary communication satellite B are equivalently equivalent to the delay time measured as described above. It may be considered that the difference AX−BX from the distance BX reaching the earth station X is measured. Based on the distance difference measured in this way, the position of the earth station X on the map is specified.
[0007]
[Problems to be solved by the invention]
However, the conventional interference source earth station location method has the following drawbacks. First, even if a geostationary communication satellite B operating in the same frequency band as that of the geostationary communication satellite A exists on the orbit, the interval between the geostationary communication satellite A and the geostationary communication satellite B is compared with the spread of the antenna side lobe of the earth station X. If it is large, the radio wave of the earth station X is not perceived by the geostationary communication satellite B. Therefore, the above distance difference cannot be measured. In other words, conditions such as the location of geostationary communication satellites in geostationary satellite orbits, the location of the interference source earth station and the transmission characteristics of radio waves, and the location of the earth station that identifies the location of the interference source earth station must be satisfied. Thus, the above method cannot be applied.
[0008]
In addition, when the above distance difference measurement is possible, a single curve (including a case where it can be regarded as a straight line) is defined as a set of points on the ground surface (on the map) that satisfy the distance difference. Although it can be determined that the earth station X is located somewhere on a curve drawn on the map (hereinafter, this curve is referred to as a solution curve), the position of the earth station X is specified as one point on the map. I can't do that. Note that how the solution curve appears depends on the positions of the stationary communication satellite A and the stationary communication satellite B with respect to the interference source earth station. In particular, as shown in FIG. 7, when looking up from the earth station X, it depends on which direction the line segment connecting the stationary communication satellite A and the stationary communication satellite B indicates.
[0009]
Even a geostationary communication satellite actually moves slightly with respect to the earth T and slightly moves from the geostationary orbit O. For example, when the first distance difference is measured, the geostationary communication satellite A and the geostationary communication satellite B are at A 1 and B 1 in FIG. 7, respectively. Suppose one is drawn. When the second distance difference measurement is performed after a lapse of time, the positions of the geostationary communication satellite A and the geostationary communication satellite B change in FIG. 7, for example, A 2 and B 2 , respectively. The solution curve different from the first solution curve is drawn on the map.
[0010]
Therefore, in principle, it is specified that the earth station X is on the intersection of the two solution curves. In practice, however, the movement of the stationary communication satellite A from A 1 to A 2 in FIG. movement of geostationary communication satellites B from 1 to B 2 may whereas not exceed sincerely look about 0.1 degrees earth together, the interval between the geostationary communications satellite a geostationary communications satellites B is a few degrees (typically Since the direction indicated by the line segment A 1 B 1 and the line segment A 2 B 2 is slightly different, the above two solution curves are parallel even if they are different. near. That is, it is practically impossible to specify the position of the earth station X as one point on the map, and in practice, it is known that there is an interference source earth station (earth station X) on one solution curve. It is difficult to stop and narrow the position narrowly.
[0011]
As described above, the conventional interference source earth station position specifying method has the following drawbacks. {Circle around (1)} The location of the interference source earth station may or may not be able to be performed, and this depends on the arrangement of stationary communication satellites in orbit and the like. {Circle around (2)} Even if the position of the interference source earth station can be specified, the specification remains one-dimensional and it is difficult to specify the two-dimensional position.
[0012]
Therefore, an object of the present invention is to provide an interference source earth station position specifying method capable of suitably specifying the position of the interference source earth station without depending on the satellite arrangement state in the geostationary orbit.
[0013]
[Means for Solving the Problems]
In order to solve the above-described problem, the invention according to claim 1 is directed to the position of the interference source earth station, which is an earth station that emits radio waves that interfere with geostationary communication satellites in geostationary orbit, at other earth stations on the ground. Interference source earth station location method specified by a certain monitoring earth station, orbiting in a direction opposite to the earth in a circular orbit at a lower altitude than a geostationary orbit, and receiving an interference radio wave from the interference source earth station A monitoring satellite that performs downlink communication at a frequency different from the frequency used by the satellite is placed, and in the process that the monitoring satellite passes directly under the interfered satellite, the radio wave that has arrived from the interference source earth station is received at least twice. Relay and send back to the earth, and whenever the monitoring earth station receives both the downlink from the monitoring satellite and the downlink from the interfered satellite, the radio wave emitted by the interference earth station is monitored via the interfered satellite. It is necessary to reach the earth station And the time required for the radio wave emitted by the interference source earth station to reach the monitoring earth station via the monitoring satellite, and based on the measurement of the time difference, the interference source earth Find the difference between the distance to the station and the distance from the monitoring satellite to the interference source earth station, and based on the obtained distance difference, find the solution curve that is a set of points where the interference source earth station may exist The position of the interference source earth station is specified as the intersection of a plurality of solution curves drawn each time the monitoring earth station receives both the downlink from the monitoring satellite and the downlink from the interfered satellite. It is characterized by doing so.
[0014]
According to a second aspect of the present invention, in the interference source earth station position specifying method according to the first aspect, the orbit of the monitoring satellite is a circular orbit inclined from the equator plane.
[0015]
According to a third aspect of the present invention, in the method of specifying the position of the interference source earth station according to the second aspect, when the first monitoring satellite orbits a circular orbit inclined from the equator plane, The inclination angle of the orbit of the first monitoring satellite is set so that the operating region, which is far away and the interference source earth station, the first monitoring satellite and the interfered satellite are not aligned, is more than half of the entire circumference, It is characterized in that a second monitoring satellite having a circular orbit set so that a range that does not become an operation region by the first monitoring satellite becomes an operation region is provided.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of an interference source earth station location specifying method according to the present invention will be described in detail with reference to the accompanying drawings.
[0017]
In FIG. 1, it is assumed that a geostationary communication satellite A in a geosynchronous orbit O is an interfered satellite receiving an interference radio wave from the earth station X (interference source earth station). This figure is drawn to look down at the North Pole, assuming that the paper is attached to the rotating earth. Therefore, the position of the earth station X does not move in the figure, and the geostationary communication satellite is at point A and hardly moves.
[0018]
A monitoring satellite M is placed as a monitoring communication satellite on a circular orbit inside the geostationary orbit O, and the monitoring satellite M orbits the orbit P in the direction opposite to the rotation of the earth. As an example, assuming that the orbit of the monitoring satellite M is 2000 km below the geostationary orbit (about 36000 km), the monitoring satellite M passes just below the stationary communication satellite A at a rate of about once every 11 hours 30 minutes. When the monitoring satellite M passes immediately below the stationary communication satellite A, the radio wave emitted from the earth station X toward the stationary communication satellite A reaches the monitoring satellite M. Similarly to the stationary communication satellite A, the monitoring satellite M relays the radio wave transmitted from the earth and sends it back toward the earth. However, the downlink of the monitoring satellite M uses a frequency different from that of the stationary communication satellite A so that the radio wave from the monitoring satellite M and the radio wave from the stationary communication satellite A can be identified and received.
[0019]
At this time, if both the relay radio wave from the geostationary communication satellite A and the downlink of the monitoring satellite M are received by the earth station G, the radio wave of the earth station X required to reach the earth station G via the geostationary communication satellite A. The difference between the time and the time required for the radio wave of the earth station X to reach the earth station G via the monitoring satellite M can be measured. Therefore, assuming that the positions of the geostationary communication satellite A and the monitoring satellite M at the time of receiving the interference radio wave from the earth station X are known, the distance AX equivalently from the geostationary communication satellite A to the earth station X is obtained by the time difference measurement. And the difference AX−MX from the distance MX from the monitoring satellite M to the earth station X is measured. This measurement is hereinafter simply referred to as distance difference measurement.
[0020]
FIG. 2 shows the observation satellite M being observed along the equatorial plane E when it is passing just below the geostationary communication satellite A. The earth T and the geostationary communication satellite A are fixed on the paper surface. The surveillance satellite M moves across the paper so as to come out. At that time, when the geostationary communication satellite A and the monitoring satellite M are looked up from the earth station X, the observation satellite M looks like FIG. 3, and the monitoring satellite M descends from the left side to the right side in the figure in order. It passes like M 1 , M 2 , M 3 . When the distance difference measurement described above is performed when the monitoring satellite M is at the positions M 1 and M 3 , two solution curves are drawn on the map. Since the directions pointed to by the line segment M 1 A and the line segment M 3 A are greatly different, the two solution curves drawn on the map cross each other with a large angle, and as a result, the position of the earth station X is set to one point. It becomes possible to specify. Actually, since the monitoring satellite M can measure the distance difference many times from M 1 through M 2 to M 3 , the position of the earth station X is specified as the point where many solution curves intersect in common. Can be further narrowed down.
[0021]
As described above, according to the method for specifying the position of the interference source earth station using the monitoring satellite M having the circular orbit P that is approximately 2000 km directly below the geostationary orbit O and is opposite to the direction of the time of the earth, the geostationary communication satellite A is stationary. Since the monitoring satellite M always passes directly below the geostationary communication satellite A every 11 and a half hours regardless of where it is on the orbit O, the earth station corresponding to the earth station G for specifying the position of the interference source earth station If it is installed in multiple locations selected appropriately, it is always possible to determine the location of the interference source earth station regardless of which geostationary communication satellites in geostationary orbit generate radio interference. The waiting time will not exceed 11 and a half hours. Of course, if a plurality of the monitoring satellites M are arranged on the same orbit, the waiting time until the position of the interference source earth station is specified can be further shortened.
[0022]
Therefore, according to the method for specifying the position of the interference source earth station according to the present embodiment, a situation in which the position of the interference source earth station cannot be determined due to the arrangement status of the geostationary communication satellite or the like does not occur. The position of the station can be specified as the intersection of a plurality of solution curves. That is, the interference source earth station position specifying method according to the present embodiment can solve the disadvantages {circle around (1)} and {circle around (2)} inherent in the conventional interference source earth station position specifying method. Moreover, the fact that the position of the interference source earth station can always be specified during a certain waiting time leads to quick removal of interference, which is highly effective in maintaining the reliability of the satellite communication line.
[0023]
In the above description, when applying the method of the present invention, the position of the geostationary communication satellite A on the geostationary orbit and the position of the earth station X on the earth may both be arbitrary, but this is the only exception. There is. That is when the earth station X is located on the equator. In such a case, when the monitoring satellite M advances on the orbit P, the earth station X, the monitoring satellite M, and the stationary communication satellite A are aligned on a straight line at a certain point. According to FIG. 3, the stationary communication satellite A is on the passing track of the monitoring satellite M. Then, the directions pointed to by the line segments M 1 A, M 2 A, M 3 A, etc. will all be the same, so the solution curve will not greatly intersect, and the situation similar to the defect (2) in the conventional method will occur, It is difficult to specify the position of the station X as one point.
[0024]
However, unlike the conventional method, the method according to the present invention has an effect of specifying that the earth station X is located on the equator when such a situation occurs. Therefore, it is not impossible to specify the position of one point on the map. In other words, when using a monitoring satellite that rotates in a circular orbit inside the geostationary orbit in the direction opposite to the direction of rotation of the earth, there is a limited condition that the positioning error increases when the interference source earth station is located on the equator. And the location of the earth station can always be specified.
[0025]
However, in the above-described embodiment, when the interference source earth station is located on the equator, it is inevitable that the position-specific error range extends particularly in the north-south direction. The cause of such inconvenience is that the earth station X, the monitoring satellite M, and the geostationary communication satellite A can be aligned in a straight line as described above. Therefore, an embodiment of a method for specifying the position of an interference source earth station that can eliminate such inconvenience will be described below.
[0026]
FIG. 4 shows the orbit P of the monitoring satellite M tilted from the equator plane E by a small angle θ. When the monitoring satellite M moves away from the equator plane E, the monitoring satellite M is on the orbit P. It will change periodically as you proceed. Initially, if the surveillance satellite M was at Ma farthest away from the equator, it would pass through Mb as the surveillance satellite M traveled, crossed the equator when it reached Mc, and the first separation after a half orbit. It reaches Md, which is reversed from north to south. After that, the movement in the opposite direction is followed, and after the half orbit of the orbit, it returns to the first Ma.
[0027]
Now, while making one orbit of the orbit P in this way, the monitoring satellite M passes near the vicinity of various geostationary communication satellites on the geostationary orbit. Now, let us say that when the vehicle passes under the vicinity of a certain stationary communication satellite A, the distance of the monitoring satellite M from the equator plane is, for example, Mb. If a straight line obtained by extending the line segment A-Mb is L, L does not intersect the earth. This means that even if the monitoring satellite M and the geostationary communication satellite A are located in a plane passing through the meridian of the earth, the interference source earth station X-the surveillance satellite M-the geostationary communication satellite A is not aligned. To do. That is, when the earth station X at an arbitrary location interferes with the geostationary communication satellite A, the position of the earth station X can be specified. Thus, if the monitoring satellite M is sufficiently away from the equator plane E and the interference source earth station X, the monitoring satellite M, and the geostationary communication satellite A are not aligned, the position of the earth station X on the ground Identification is absolutely possible.
[0028]
Even if the orbit P of the monitoring satellite M is tilted from the equatorial plane E, the interference source earth station X-monitoring satellite M-stationary communication is in the range where L (a straight line extending the line segment AM) intersects the earth. Since the satellites A may be arranged in a straight line, the location of the interference source earth station X may be difficult as in the first embodiment described above. That is, depending on the distance from the orbital plane of the monitoring satellite M, a range where L does not intersect the earth (an operating area where the position of the interference source earth station can be absolutely determined) and a range where L intersects the earth (interference) It can be divided into areas where the location of the source earth station becomes difficult).
[0029]
FIG. 5 (a) shows a region in which the first monitoring satellite M goes around the orbit and is sufficiently separated from the equator plane (a range in which L does not intersect the earth). It shows that two
[0030]
Here, the second monitoring satellite M ′, which is another monitoring satellite, is provided, and the shape and inclination angle of the orbit P ′ are the same as those of the first monitoring satellite M (see FIG. 5B). The
[0031]
In this way, if two monitoring satellites are used, the position of the earth station can always be specified when any earth station gives radio wave interference to any geostationary communication satellite. Further, when the operation areas of the monitoring satellite M and the monitoring satellite M ′ are provided in a complementary manner as in the present embodiment, no matter where the interference source earth station is on the earth, the position identification is executed. The waiting time does not exceed 11 and a half hours. Note that if the inclination angle θ formed by the trajectory P of the monitoring satellite M and the trajectory P ′ of the monitoring satellite M ′ and the equator plane E is increased, the respective operation areas are expanded, and therefore both the monitoring satellite M and the monitoring satellite M ′. When the interference source earth station is located in the area included in the operating area of both satellites, there is an advantage that the waiting time until the position can be further reduced.
[0032]
In the two embodiments described above, the orbit of the monitoring satellite is set to a circular orbit that is 2000 km lower than the geostationary orbit, but the orbit of the monitoring satellite is not particularly limited to this altitude. However, since the surveillance satellite and the geostationary satellite fly in opposite directions and pass each other, it is necessary to take a sufficient altitude difference to maintain safety. On the other hand, when detecting the time difference between the signal arriving on the propagation path of the interference source earth station → stationary communication satellite → monitoring earth station and the signal arriving on the propagation path of interference source earth station → monitoring satellite → monitoring earth station, both propagations are detected. There is a problem that the greater the distance of the road, the more complicated signal processing is required. From this point, it is better that the difference in altitude between the monitoring satellite and the geostationary satellite is small. The altitude difference of 2000 km described in the above embodiment is desirable as the altitude difference that satisfies both the contradictory conditions.
[0033]
Even if the orbit of the monitoring satellite that runs backward to the earth's rotation is provided outside the geostationary orbit, the location of the interference source earth station can be specified. The satellite orbit must be set inside the geostationary orbit. This is because, in general, before a satellite ends its life in a geosynchronous orbit, the rules for moving the satellite out of a geosynchronous orbit in order to prevent the satellite from drifting and causing danger to the geostationary satellite in operation. Because it is. In fact, since used geostationary satellites are drifting over a wide altitude range outside the geostationary orbit, it is dangerous to place a retrograde surveillance satellite in them.
[0034]
【The invention's effect】
As described above, according to the method for specifying the position of the interference source earth station according to claim 1, a monitoring satellite orbiting in a direction opposite to the earth is placed on a circular orbit whose altitude is lower than that of the geostationary orbit. In the process of passing directly under the interfering satellite, relay the radio waves arriving from the interfering source earth station at least twice and send it back to the earth. Both the downlink from the monitoring satellite and the downlink from the interfered satellite are monitored. The solution curve is obtained every time it is received by the station, and the position of the interference source earth station is specified as the intersection of the plurality of solution curves. A situation where the position cannot be specified does not occur, and the position of the interference source earth station can be specified as an intersection of a plurality of solution curves. In other words, the interference source earth station position specifying method according to the present invention can solve the disadvantages {circle around (1)} and {circle around (2)} inherent in the conventional interference source earth station position specifying method. Moreover, the fact that the position of the interfering earth station can be specified during a certain waiting time leads to quick removal of the interference, which is very effective in maintaining the reliability of the satellite communication line.
[0035]
According to the method for specifying the position of the interference source earth station according to claim 2, since the orbit of the monitoring satellite is a circular orbit inclined from the equator plane, it is difficult to specify the position of the interference source earth station on the equator plane. Can be suppressed.
[0036]
According to the method for specifying the position of the interference source earth station according to claim 3, when the first monitoring satellite orbits the circular orbit inclined from the equator plane, the interference source earth station is sufficiently separated from the equator plane. In addition, the inclination angle of the orbit of the first monitoring satellite is set so that the operating area in which the first monitoring satellite and the interfered satellite are not aligned is more than half of the entire circumference, and the operating area by the first monitoring satellite is set. Since the second monitoring satellite in which the orbit is set so that the range that does not become the operating area is provided, it is possible to always specify the position of the interference source earth station in the entire area on the ground.
[Brief description of the drawings]
FIG. 1 shows transmission / reception of radio waves in a geostationary communication satellite A and a monitoring satellite M in a geostationary orbit O, a ground station X and a ground station G in the geostationary orbit O in the method for specifying the position of an interference earth station according to the first embodiment. It is explanatory drawing which shows a relationship.
FIG. 2 is an explanatory diagram showing a positional relationship among the stationary communication satellite A, the monitoring satellite M, and the earth station X in the first embodiment, observed along the equator plane.
FIG. 3 is an explanatory diagram showing a positional relationship between a stationary communication satellite A and a monitoring satellite M observed from the earth station X. FIG.
FIG. 4 is an explanatory diagram showing a positional relationship among the stationary communication satellite A, the monitoring satellite M, and the earth station X in the second embodiment, observed along the equator plane.
FIG. 5A is an explanatory diagram showing an operating region of a monitoring satellite M having an orbit P inclined by θ from the equator plane. (B) It is explanatory drawing which shows the operation area | region of the monitoring satellite M 'which has the orbit P' inclined by (theta) from the equatorial plane.
FIG. 6 is an explanatory diagram showing radio wave transmission / reception relationships between a geostationary communication satellite A and geostationary communication satellite B on a geostationary orbit, and a ground earth station X and an earth station G in a conventional method for specifying the position of an interference source earth station. is there.
FIG. 7 is an explanatory diagram of changes in position of the geostationary communication satellite A and B with respect to the geostationary orbit O;
[Explanation of symbols]
A Geostationary communication satellite M, M 'Monitoring satellite X Earth station (interference source earth station)
G Earth station (monitoring earth station)
O Geostationary orbits P and P '
Claims (3)
静止軌道より高度が低い円軌道上を地球と逆向きに周回し、干渉源地球局からの干渉電波を受ける被干渉衛星が使用する周波数とは異なる周波数で下り回線の通信を行う監視衛星を置き、
上記監視衛星が、被干渉衛星の真下を通過する過程で、少なくとも２回以上、干渉源地球局から到来した電波を中継して地球方向へ送り返し、
上記監視衛星からの下り回線と被干渉衛星からの下り回線を共に監視地球局によって受信する毎に、干渉源地球局が発した電波が被干渉衛星を介して監視地球局に至るに要した時間と、干渉源地球局が発した電波が監視衛星を介して監視地球局に至るに要した時間の差を測定し、その時間の差の測定に基づいて、被干渉衛星から干渉源地球局に至る距離と、監視衛星から干渉源地球局に至る距離の差を求め、その求めた距離の差に基づいて、干渉源地球局が存在する可能性のある点の集合である解曲線を地図上に引き、
上記監視衛星からの下り回線と被干渉衛星からの下り回線を共に監視地球局によって受信する毎に引かれた複数の解曲線の交点として、干渉源地球局の位置を特定するようにしたことを特徴とする干渉源地球局の位置特定方法。This is a method for locating an interference source earth station that identifies the position of an interference source earth station, which is an earth station that emits radio waves that interfere with geostationary communication satellites in geostationary orbit, by a monitoring earth station that is another earth station on the ground. hand,
A monitoring satellite that orbits in the opposite direction to the earth on a circular orbit where the altitude is lower than that of the geostationary orbit and that performs downlink communication at a frequency different from the frequency used by the interfered satellite that receives the interference from the interference source earth station is placed. ,
In the process in which the monitoring satellite passes directly under the interfered satellite, it relays the radio wave coming from the interference source earth station at least twice or more and sends it back to the earth.
Each time the monitoring earth station receives both the downlink from the monitoring satellite and the downlink from the interfered satellite, the time taken for the radio wave emitted by the interference source earth station to reach the monitoring earth station via the interfered satellite And the time difference required for the radio wave emitted by the interference source earth station to reach the monitoring earth station via the monitoring satellite, and based on the measurement of the time difference, the interference satellite to the interference source earth station The difference between the distance from the monitoring satellite to the interference source earth station is obtained, and a solution curve, which is a set of points where the interference source earth station may exist, is displayed on the map based on the obtained distance difference. Pull
The position of the interference source earth station is specified as the intersection of a plurality of solution curves drawn each time the downlink from the monitoring satellite and the downlink from the interfered satellite are received by the monitoring earth station. A method for locating an interfering earth station characterized by
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| CN104884350A (en) * | 2012-12-05 | 2015-09-02 | Ses有限公司 | Apparatuses, systems and methods for obtaining information about electromagnetic energy emitted from the earth, such as for locating an interference source on earth |
| US10444371B2 (en) | 2014-03-21 | 2019-10-15 | The Boeing Company | Interference geolocation using a satellite constellation |
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| GB0606501D0 (en) * | 2006-03-31 | 2006-05-10 | Qinetiq Ltd | Satellite ephemeris error |
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| EP2365646A1 (en) * | 2010-03-12 | 2011-09-14 | Inmarsat Global Limited | Satellite beam monitoring by using a monitoring satellite |
| JP5599371B2 (en) * | 2011-07-28 | 2014-10-01 | 三菱電機株式会社 | Positioning device |
| US10720986B2 (en) | 2012-12-05 | 2020-07-21 | Ses S.A. | Apparatuses, systems and methods for obtaining information about electromagnetic energy emitted from the earth, such as for locating an interference source on earth |
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| CN113131988B (en) * | 2021-03-03 | 2022-02-22 | 中国科学院国家空间科学中心 | Multi-dimensional GSO satellite system compatibility analysis method |
| CN114817862B (en) * | 2022-05-26 | 2023-09-26 | 江苏省地震局 | Method and device for positioning electromagnetic interference source |
| CN115426027B (en) * | 2022-08-23 | 2023-07-21 | 中国科学院国家空间科学中心 | Interference distribution-based method for calculating position of earth station of interfered system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104884350A (en) * | 2012-12-05 | 2015-09-02 | Ses有限公司 | Apparatuses, systems and methods for obtaining information about electromagnetic energy emitted from the earth, such as for locating an interference source on earth |
| CN104884350B (en) * | 2012-12-05 | 2017-03-15 | Ses有限公司 | In order to position the equipment, system and method for obtaining the information relevant with the electromagnetic energy from earth transmission of tellurian interference source etc. |
| US10444371B2 (en) | 2014-03-21 | 2019-10-15 | The Boeing Company | Interference geolocation using a satellite constellation |
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