JP3586421B2

JP3586421B2 - Transmission power control device and wireless transmission device using the same

Info

Publication number: JP3586421B2
Application number: JP2000360021A
Authority: JP
Inventors: 朝彦坂口
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2000-11-27
Filing date: 2000-11-27
Publication date: 2004-11-10
Anticipated expiration: 2020-11-27
Also published as: JP2002164800A

Description

【０００１】
【発明の属する技術分野】
この発明は移動体に搭載した無線送信装置から静止衛星または非静止衛星に向けて通信する際の送信電力制御装置とこれを用いた無線送信装置の改良に関する。
【０００２】
【従来の技術】
地上に設置された地球局に設けた無線送信装置から静止衛星または非静止衛星（以下衛星という）に向けて通信する場合、その通信の品質を向上する上で、衛星における受信信号の電界強度が低すぎると受信が困難になるし、高すぎても他からの弱い信号に影響して他の通信品質を低下させるので、適当なレベルに一定化することが必要である。
【０００３】
もちろん、地球局のアンテナは刻々と変化する衛星の位置を追跡して、アンテナのビーム方向で常に衛星を捕らえるように制御される。それでも指向方向が水平に近い方向では大地の影響を受けて期待したビームパターンが得られない場合があるし、また、周波数によっては大気中の気象現象の影響を受けることもある。したがって衛星の側で安定した受信電界強度を確保することはそれほど容易ではない。
【０００４】
このような問題に対応する例として、図９は、例えば特開平９−１９２８４号公報に開示されたもので、地球局から送信する信号にパイロット信号を載せ、これを受信した衛星から同じ信号を返送して地球局で受信する閉ループを構成し、地球局は返送された信号中のパイロット信号を解析して、この結果により衛星の受信電界強度が一定になるように地球局送信機の送信電力を可変減衰器により調整するものである。
【０００５】
次に動作について図により説明する。
パイロット信号発生部２４が発生するパイロット信号及び送信データ処理部２５からのデータを加算器２６で加算して送信部１に出力し、可変減衰器９を通じてアンテナ２から非静止衛星（図示しない）に送信する。
非静止衛星からのビーコン信号電波及び非静止衛星で返送するパイロット信号電波をアンテナ２３、受信部１０で受信し、ビーコン信号検出部１１、パイロット信号検出部１２でビーコン信号Ｒｂ、パイロット信号Ｒｐを検出する。
【０００６】
即ち、地球送信局２１が受信するパイロット信号Ｒｐのレベルは、送信電波Ｗｄｐにおけるパイロット信号の受信レベルＲｐに、非静止衛星のトランスポンダを通じた変換利得Ｇｓを加え、かつ、地球送信局２１と非静止衛星との間の電波伝播路の損失Ｌ（往復路２Ｌ）を差し引いた値となる。
また、地球局が受信するビーコン信号Ｒｂのレベルは、非静止衛星のビーコン信号の送信レベルＰＢから地球局と非静止衛星との間の電波伝播路の損失Ｌを差し引いた値となる。
Ｒｐ＝Ｐｐ−Ｌ−Ｇｓ−Ｌ＝Ｐｐ＋Ｇｓ−２Ｌ
Ｒｂ＝ＰＢ−Ｌ
この信号レベルの差を演算部１３で平均化し、この補正信号Ｓｃｐを制御部１４で制御信号Ｓｃに生成して可変減衰器９が高周波信号Ｓｔのレベルを可変（減衰）し、その可変高周波信号Ｓｖｔを電力増幅部１７、アンテナ２を通じて送信電波Ｗｄｐとして非静止衛星へ送信する。
Ｓｃｐ＝−（Ｒｐ−Ｒｂ）／２
【０００７】
ところで、衛星からの送信チャンネル数は容易に増設は出来ないし、電力も節約したいから極めて貴重であるということが言えるが、図９の従来の例では、衛星からの送信チャンネルの何％かを常に送信電力制御のために割かなければならないと言う問題がある。また、安定した閉ループを構成するためには、地球局側の姿勢が安定していることが必要で、地球局が姿勢変化の激しい移動体（例えば航空機、艦船、車両）搭載局である場合には適用できないと言う問題があった。
【０００８】
【発明が解決しようとする課題】
従来の衛星通信システムに於ける送信電力制御装置は、衛星からの送信手段の何％かを常に電力制御のために割かなければならないと言う問題があった。また、閉ループを構成するため、地球局が姿勢変化の激しい移動体搭載局である場合には適用できないと言う問題があった。
そして、複数の基地局からレベルの異なる信号が同時に衛星に到達すると干渉によりレベルの低い信号の受信が困難となるという問題があった。
【０００９】
この発明は、移動体に搭載された地球局にも適用することができ、衛星側の送信チャンネルを制御のために使用する必要のない送信電力制御装置およびこれを用いた無線送信装置を得ることを目的とする。
【００１０】
【課題を解決するための手段】
この発明による送信電力制御装置は、移動体に搭載され、宇宙局に到達する電波の電界強度を一定になるよう制御する送信電力制御装置であって、
高周波信号を発生する送信機、
複数の素子アンテナを有し前記送信機の出力を放射するフェーズとアレイアンテナ、
前記移動体の位置と姿勢を算出する移動体位置姿勢算出手段、
前記宇宙局の位置を、予め入力された軌道情報から算出する宇宙局位置算出手段、
前記移動体位置姿勢算出手段の出力と前記宇宙局位置算出手段の出力とをもとに、前記移動体と前記宇宙局との距離を算出するとともに、前記素子アンテナの励振位相を制御して前記フェーズドアレイアンテナのビーム方向を制御する空中線制御器、
前記送信機と前記フェーズドアレイアンテナとの間に挿入され、前記空中線制御器の信号により、前記送信機の出力をビーム方向および前記移動体と前記宇宙局との距離に応じて減衰させる可変減衰器を備えたものである。
【００１２】
また、移動体に搭載され、互いに異なる方向に向けて配置されるとともに、それぞれのビーム方向が互いに異なる角度に制御可能な複数のフェーズドアレイアンテナを有し、衛星に搭載された宇宙局との間で無線通信を行う無線送信装置であって、
高周波信号を発生する送信機と、
前記移動体の位置と姿勢を算出する移動体位置姿勢算出手段と、
前記宇宙局の位置を、予め入力された軌道情報から算出する宇宙局位置算出手段と、
前記移動体位置姿勢算出手段の出力と前記宇宙局位置算出手段の出力とをもとに、前記複数のフェーズドアレイアンテナのビーム方向をそれぞれ前記宇宙局の方向に制御する空中線制御器と、
前記空中線制御器の信号により、前記送信機から前記ビームが前記宇宙局の方向に向けられたフェーズドアレイアンテナに入力する送信電力を、前記ビームが前記宇宙局の方向に向けられたフェーズドアレイアンテナの数とそれぞれのビーム方向に応じてそれぞれ制御する複数の可変減衰器とを有する送信電力制御装置を備え、
前記宇宙局が前記複数のフェーズドアレイアンテナの複数のビームの指向方向内にあるとき、前記宇宙局が受信する受信電界強度を前記ビーム方向と前記ビームの数とにかかわらず一定に制御するものである。
【００１３】
また、移動体に搭載され、ビーム方向の制御が可能なフェーズドアレイアンテナを有し、衛星に搭載された宇宙局との間で無線通信を行う無線送信装置であって、
高周波信号を発生する送信機と、
移動体の位置と姿勢を算出する移動体位置姿勢算出手段と、
宇宙局の位置を予め入力された軌道情報から算出する宇宙局位置算出手段と、移動体位置姿勢算出手段の出力と宇宙局位置算出手段の出力とをもとに、移動体と宇宙局との距離を算出するとともにフェーズドアレイアンテナのビーム方向を制御する空中線制御器と、空中線制御器の信号により、送信機からフェーズドアレイアンテナに入力する送信電力を、フェーズドアレイアンテナのビーム方向および移動体と宇宙局間の距離とに応じて制御する可変減衰器とを有する送信電力制御装置とを備え、
ビーム方向があらかじめ定めた所定の角度内にあるとき、宇宙局が受信する受信電界強度を、ビーム方向、及び、移動体と宇宙局との間の距離にかかわりなく、一定に制御するものである。
【００１４】
また、移動体に搭載され、互いに異なる方向に向けて配置されるとともに、それぞれのビーム方向が互いに異なる角度に制御可能な複数のフェーズドアレイアンテナを有し、衛星に搭載された宇宙局との間で無線通信を行う無線送信装置であって、
高周波信号を発生する送信機と、
前記移動体の位置と姿勢を算出する移動体位置姿勢算出手段と、
前記宇宙局の位置を予め入力された軌道情報から算出する宇宙局位置算出手段と、
前記移動体位置姿勢算出手段の出力と前記宇宙局位置算出手段の出力とをもとに、前記移動体と前記宇宙局との距離を算出するとともに前記複数のフェーズドアレイアンテナのビーム方向をそれぞれ前記宇宙局の方向に制御する空中線制御器と、
前記空中線制御器の信号により、前記送信機から前記ビームが前記宇宙局の方向に向けられたフェーズドアレイアンテナに入力する送信電力を、前記ビームが前記宇宙局の方向に向けられたフェーズドアレイアンテナの数と、それぞれのビーム方向と、前記移動体と前記宇宙局間の距離とに応じて制御する複数の可変減衰器を有する送信電力制御装置とを備え、
前記宇宙局が前記複数のフェーズドアレイアンテナの内の複数のビーム指向方向内にあるとき、前記宇宙局が受信する受信電界強度を前記ビームの方向、及び前記ビームの数と、前記移動体と前記宇宙局との距離にかかわりなく一定に制御するものである。
【００１５】
また、移動体は航空機であるものである。
【００１６】
また、宇宙局は地球を周回する衛星に搭載された衛星局であるものである。
【００１７】
また、衛星は静止衛星であるものである。
【００１８】
【発明の実施の形態】
実施の形態１．
図１はこの発明による送信電力制御装置とこれを備えた無線送信装置の構成を示し、１は図示しない移動体、例えば航空機に搭載され衛星４に信号を送信する送信機、２は送信機１の信号を衛星に向け送信するフェーズドアレイアンテナ、３は説明のため記載した送信波、４はこの通信を行う対象の通信衛星（衛星局または宇宙局とも言う）であり静止衛星であるか非静止衛星であるかは問わないが、説明の都合上ここでは静止衛星であるとして説明する。５は送信機１が搭載されている図示しない航空機の地球上の位置及び姿勢を出力する慣性航法装置（移動体位置姿勢算出手段という）、６はフェーズドアレイアンテナ２の指向パターンを制御する空中線制御器で、あらかじめ入力された通信衛星４の軌道情報６１を記憶し、これをもとに衛星の現在の位置を算出する（宇宙局位置算出手段という）。空中線制御器４は、また、移動体位置姿勢算出手段の出力と宇宙局位置算出手段の出力とをもとに、フェーズドアレイアンテナ２のビーム方向を算出して制御するとともに、地球局と宇宙局との間の距離をも算出する。
７は送信機１の出力を増幅する電力増幅器、９は送信機１と電力増幅器７との間に挿入された可変減衰器で、空中線制御器６からの信号により送信電力レベルを調整することができる。
送信機１と可変減衰器９とフェーズドアレイアンテナ２と空中線制御器６と軌道データ６１はこの発明に言う送信電力制御装置１００を構成している。
航空機地球局８はこの発明に言う無線送信装置である。
【００１９】
次に動作について説明する。
フェーズドアレイアンテナ２は、公知のとおり複数のアンテナ素子が面状（平面とは限らない）に配列され、そのアンテナ素子の各々が位相制御されて励振されることにより、任意の方向（但し放射が不十分となる方向が存在する場合もある）に放射を集中したビームを指向させることができる。図１では慣性航法装置５からの航空機の位置と姿勢データと通信衛星の位置データ６１とにもとづき、空中線制御器６が通信衛星の方向を算出し、フェーズドアレイアンテナ２を制御して通信衛星４の方向にビームが制御される。
【００２０】
このようにして制御されたビームの方向を変化させた場合の最大利得の包絡線７１を図２に示す。図２はフェーズドアレイアンテナ２のビーム方向を−９０度から＋９０度まで変化させた場合の利得の変化を示した図であり、アングル０度はアンテナ面に直交する方向、アングル９０度は面に平行する方向である。図２に示すようにフェーズドアレイアンテナ２の利得特性はアンテナ面に直交する方向から離れると、アンテナを見る見かけの面積が減少するので（アンテナの形状にもよるが）ほぼ余弦曲線に近い特性で利得が低下する。
図２の特性をＡ（ｄｂ）＝ｋｆ（α）と表す。
ここでｋは定数である。
上記の角度αはこの航空機から（正確にはフェーズドアレイアンテナの面から）通信衛星４を見る方向として空中線制御器６から常に出力される。
【００２１】
空中線制御器６の出力αは可変減衰器９にも出力され、可変減衰器９が制御される。図３の７３はフェーズドアレイアンテナ２のビーム方向の変化に対する可変減衰器９の利得特性の変化を示す。図３の特性は −９０＜α＜＋９０の範囲で
Ｂ＝−ｍ／ｆ（α）（ｄｂ）に設定されている。この特性は図２のフェーズドアレイアンテナ２の特性のカーブをキャンセルする特性になっている。
但し αが±９０度に近いとき、ｆ（α）がゼロに近くなり、Ｂは無限に大きくなるので実用にならない範囲が生じる。ゲインが安定する角度範囲は±８５度程度が限界となる。
そしてＢ＜０（ｄｂ）であり、ｍは定数である。
この結果フェーズドアレイアンテナ２から送信される送信電力Ｐは
−９０＜α＜＋９０の範囲で
Ｐ＝ｍｋｆ（α）／ｆ（α）＝ｍｋ（ｄｂ）即ち、一定となる。これを図４に示す。これによりこの航空機地球局８を搭載した航空機の位置、姿勢の変化にかかわりなく（但し前述のとおり、αが±８５度の範囲内で）、衛星に向かって放出される電波の電力密度は一定となり、衛星４までの距離がほぼ一定なら、衛星４が受信する信号強度は常に一定となる。周知のとおり衛星４が静止衛星なら距離はほぼ一定である。
【００２２】
図１の構成では、従来のように通信衛星４から地球局側へフィードバックするループを設けていないので、貴重な通信衛星側からの送信チャンネルを制御のために使用すると言うことが無くなり、経済性が向上する。
また、常に一定の受信信号電界強度を確保できることから、必要以上に余裕を見た信号強度に設定する必要が無くなり、必要最小限度の信号レベルに設定できることから他の局と干渉して、他局の通信に妨害を与える可能性も減少する。
【００２３】
実施の形態２．
実施の形態１の説明では、通信衛星４がフェーズドアレイアンテナ２の面から８５度以上の方向になった場合について説明していない。衛星の位置が地平線以下になる場合の対応を考慮する必要がないことは当然であるが、航空機の姿勢によってはフェーズドアレイアンテナ２の８５度方向を越える方向に対して対応を要する場合が生じる。
一般に航空機に搭載される通信用フェーズドアレイアンテナ２は、図５に示すように、例えば機体の両側に異なる方向に向けて２基以上が配置され、必要に応じて切り替え使用される。図は航空機を正面から見た図で、左右が水平を示す。図に於いて図示しない第１、第２のアンテナはそれぞれ真上から４５度逆方向に傾けて配置されている。７４は第１のアンテナがカバーする角度範囲で、７５は第２のアンテナがカバーする角度範囲である。
【００２４】
図６に実施の形態２による送信電力制御装置とこれを用いた無線送信装置の構成を示す。図に於いて３９は第２の可変減衰器、３７は第２の電力増幅器、３２は第２のフェーズドアレイアンテナである。なお、９、７、２はそれぞれ第１の可変減衰器、第１の電力増幅器、第１のフェーズドアレイアンテナと呼ぶ。
第１、第２のアンテナの切り換えは空中線制御器６によって、一方のアンテナのアンテナ素子への給電を遮断する（可変減衰器６、または３６により）ことで行われる。真上の範囲の約８５度の範囲は第１、第２のいずれのアンテナでも対応することができるし、又、両アンテナを（相互の位相を協調させるように考慮して）使用してもよい。
図７は角度範囲が０度の両側（−４５度〜＋４５度）では両アンテナを同時に使用して、角度が大きくなるにつれ、片方の送信電力を徐々に低減することにより、切替えのショックが生じないようにした使用方法を示している。図７の縦軸は可変減衰器９の減衰レベルを示している。
送信機１と可変減衰器９及び３９、フェーズドアレイアンテナ２及び３２、空中線制御器６と軌道データ６１はこの発明に言う送信電力制御装置１００を構成している。
航空機地球局８はこの発明に言う無線送信装置である。
この構成とすることにより航空機の姿勢に関係なく、全天の視認可能な、如何なる位置にある衛星に対しても、制御可能な角度範囲で対応できる。
【００２５】
実施の形態３．
周知のとおり、ある程度の広がり角で放射された電波の電界強度は距離の２乗で減衰する。
衛星が静止衛星の場合には地球局が地球表面上を移動しても、大した距離の変化は生じない。しかし、衛星が非静止衛星で、特に低軌道をとるものである場合には、地球局の位置の変化による距離の差が大きくなり（例えば近い場合は数１００Ｋｍ，遠い場合は１００００Ｋｍ程度）距離の近い地球局の電波が強すぎて、遠方の局の電波の受信が困難になる場合がある。
【００２６】
実施の形態１で説明したとおり、空中線制御器６はフェーズドアレイアンテナ２のビーム方向を算出する際、同時に地球局と衛星局との距離も算出可能であるから、フェーズドアレイアンテナ２に入力する送信電力を距離の（１／２）乗に比例して制御すれば、衛星までの距離にかかわらず受信電界強度をより一定に制御できる。図８は距離の変化に対する可変減衰器９の減衰制御量
〔Ａ・（距離）^１／２〕を示したものである。
縦軸のｍｋは実施の形態１の図４のｍｋと同じである。
実施の形態１で説明したビーム方向によるゲインの補正と、本実施の形態で説明した距離による補正とをともに実施すると、ゲインの変化幅が極めて広くなり、可変減衰器６のみでは対応できない可能性もある。このようなばあいには、図１の電力増幅器７による増幅を併用して変化幅を大きくすればよい。
【００２７】
以上の説明に於いて、移動体は航空機として説明したが、艦船、車両あるいは他の人工衛星であっても同様である。また、衛星局は静止衛星、非静止衛星のいずれであってもよいだけでなく、必ずしも地球を周回する衛星に限定されず、他の惑星へと飛行を続ける宇宙局であってもよい。
【００２８】
【発明の効果】
以上に説明したように、この発明の送信電力制御装置は、フェーズトアレイアンテナのビーム方向と、相手宇宙局との距離とに応じて送信電力を制御する可変減衰装置を備えているので、受信側の位置、相手局の位置にかかわらず受信電界強度を一定にすることができる。また、受信側からの送信を必要としない。
【００３０】
また、設置角度の異なる複数のフェーズドアレイアンテナを備え、各アンテナの方向を同じ宇宙局の方向に向け、宇宙局方向に向いているアンテナの数と各アンテナの指向方向とにより、各フェーズドアレイアンテナの入力を制御しているので、移動体の広い角度での姿勢変化に対してもビームの角度に係わりなく宇宙局に於ける受信電界強度を一定にすることが出来る。
【００３１】
また、ビーム角度による制御だけでなく、衛星と地球局との距離に応じた制御を併用しているので、衛星が非静止衛星である場合でもビームの角度と距離に係わりなく衛星に於ける受信電界強度を一定にすることが出来る。
【００３２】
また、設置角度の異なる複数のフェーズドアレイアンテナのうち、宇宙局の方向に指向させることのできたアンテナの入力を、指向させたアンテナの数と、各アンテナの指向方向と、宇宙局までの距離とにより制御しているので、移動体の広い角度での姿勢変化および距離の変化に対しても宇宙局に於ける受信電界強度を一定にすることが出来る。
【００３３】
また、無線送信装置は航空機に搭載されていて、その姿勢変化角度が大きくても衛星に於ける受信電界強度を一定にすることが出来る。
【００３４】
また、衛星は地球を周回する衛星であり、その距離の変化が大きくても衛星に於ける受信電界強度を一定にすることが出来る。
【００３５】
また、衛星は静止衛星であるので、距離の変化も小さく衛星に於ける受信電界強度を一定にすることが出来る。
【図面の簡単な説明】
【図１】この発明の実施の形態１による送信電力制御装置とこれを用いた無線送信装置の構成図である。
【図２】図１のフェーズドアレイアンテナの特性図である。
【図３】図１の可変減衰器の特性説明図である。
【図４】図１の装置による衛星での受信電界強度の説明図である。
【図５】実施の形態２による送信電力制御装置の特性図である。
【図６】実施の形態２による送信電力制御装置とこれを用いた無線送信装置の構成図である。
【図７】図５の特性の場合のアンテナ電力の説明図である。
【図８】実施の形態３による距離による送信電力制御特性の説明図である。
【図９】従来の送信電力制御装置の構成図である。
【符号の説明】
１送信機、２アンテナまたはフェーズドアレイアンテナ、
４通信衛星、５慣性航法装置、６空中線制御器、
７電力増幅器、８航空機地球局（無線送信装置）
９可変減衰器、６１通信衛星の軌道データ
１００送信電力制御装置。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transmission power control device for communicating from a wireless transmission device mounted on a mobile object to a geostationary satellite or a non-geostationary satellite, and to an improvement of a wireless transmission device using the same.
[0002]
[Prior art]
When communication is performed from a wireless transmitter provided at an earth station installed on the ground to a geostationary satellite or a non-geostationary satellite (hereinafter referred to as a satellite), in order to improve the quality of the communication, the electric field strength of the received signal at the satellite increases. If it is too low, reception becomes difficult, and if it is too high, it affects other weak signals and degrades other communication quality. Therefore, it is necessary to keep the communication level at an appropriate level.
[0003]
Of course, the antenna of the earth station is controlled to keep track of the satellite's ever-changing position and to always catch the satellite in the beam direction of the antenna. Even so, if the pointing direction is nearly horizontal, the expected beam pattern may not be obtained due to the influence of the ground, and depending on the frequency, it may be affected by atmospheric meteorological phenomena. Therefore, it is not so easy to secure a stable reception electric field strength on the satellite side.
[0004]
As an example corresponding to such a problem, FIG. 9 is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-19284, in which a pilot signal is placed on a signal transmitted from an earth station, and the same signal is transmitted from a satellite receiving the pilot signal. The earth station analyzes the pilot signal in the returned signal and returns the transmission power of the earth station transmitter so that the received electric field strength of the satellite becomes constant. Is adjusted by a variable attenuator.
[0005]
Next, the operation will be described with reference to the drawings.
The pilot signal generated by the pilot signal generation unit 24 and the data from the transmission data processing unit 25 are added by the adder 26 and output to the transmission unit 1, and transmitted from the antenna 2 to the non-geostationary satellite (not shown) through the variable attenuator 9. Send.
A beacon signal radio wave from a non-geostationary satellite and a pilot signal radio wave returned by the non-geostationary satellite are received by the antenna 23 and the reception unit 10, and the beacon signal detection unit 11 and the pilot signal detection unit 12 detect the beacon signal Rb and the pilot signal Rp. I do.
[0006]
That is, the level of the pilot signal Rp received by the earth transmitting station 21 is obtained by adding the conversion gain Gs through the transponder of the non-geostationary satellite to the reception level Rp of the pilot signal in the transmission radio wave Wdp, and This is a value obtained by subtracting the loss L of the radio wave propagation path between the satellite and the satellite (round-trip path 2L).
The level of the beacon signal Rb received by the earth station is a value obtained by subtracting the loss L of the radio wave propagation path between the earth station and the non-geostationary satellite from the transmission level PB of the beacon signal of the non-geostationary satellite.
Rp = Pp-L-Gs-L = Pp + Gs-2L
Rb = PB-L
The difference between the signal levels is averaged by the calculation unit 13, the correction signal Scp is generated as the control signal Sc by the control unit 14, and the variable attenuator 9 changes (attenuates) the level of the high-frequency signal St. The Svt is transmitted to the non-geostationary satellite via the power amplifier 17 and the antenna 2 as a transmission radio wave Wdp.
Scp = − (Rp−Rb) / 2
[0007]
By the way, it can be said that the number of transmission channels from the satellite is extremely valuable because it is not easy to increase the number of transmission channels from the satellite and to save power, but in the conventional example of FIG. There is a problem that it must be divided for transmission power control. In addition, in order to form a stable closed loop, the attitude of the earth station side must be stable, and when the earth station is a mobile station with a rapidly changing attitude (for example, an aircraft, a ship, a vehicle), Was not applicable.
[0008]
[Problems to be solved by the invention]
The transmission power control device in the conventional satellite communication system has a problem that some% of the transmission means from the satellite must always be allocated for power control. Further, there is a problem that the method cannot be applied when the earth station is a mobile-mounted station whose attitude changes drastically because it forms a closed loop.
Then, when signals having different levels arrive at the satellite simultaneously from a plurality of base stations, there is a problem that it becomes difficult to receive a low-level signal due to interference.
[0009]
The present invention can also be applied to an earth station mounted on a mobile body, and obtains a transmission power control device that does not need to use a transmission channel on a satellite side for control and a radio transmission device using the same. With the goal.
[0010]
[Means for Solving the Problems]
A transmission power control device according to the present invention is a transmission power control device that is mounted on a mobile object and controls the electric field intensity of a radio wave reaching a space station to be constant,
A transmitter that generates a high-frequency signal,
A phase and array antenna having a plurality of element antennas and radiating the output of the transmitter,
Moving body position and orientation calculating means for calculating the position and orientation of the moving body,
Space station position calculating means for calculating the position of the space station from orbit information input in advance,
Based on the output of the moving body position and orientation calculating means and the output of the space station position calculating means, calculate the distance between the moving body and the space station, and control the excitation phase of the element antenna to An antenna controller for controlling the beam direction of a phased array antenna,
A variable attenuator that is inserted between the transmitter and the phased array antenna and attenuates the output of the transmitter according to the beam direction and the distance between the moving object and the space station by a signal of the antenna controller ; It is provided with.
[0012]
In addition, it has a plurality of phased array antennas mounted on a mobile object and arranged in different directions from each other and each beam direction can be controlled at a different angle from each other. A wireless transmission device that performs wireless communication in,
A transmitter for generating a high-frequency signal;
Moving body position and orientation calculating means for calculating the position and orientation of the moving body,
Space station position calculating means for calculating the position of the space station from orbit information input in advance,
An antenna controller that controls the beam directions of the plurality of phased array antennas in the direction of the space station, based on the output of the moving object position / posture calculation means and the output of the space station position calculation means,
By the signal of the antenna controller, the transmission power from the transmitter to the phased array antenna in which the beam is directed to the space station, the phased array antenna in which the beam is directed to the space station , A transmission power control device having a plurality and a plurality of variable attenuators each controlling according to the number and each beam direction,
When the space station is in the direction of the plurality of beams of the plurality of phased array antennas, the received electric field intensity received by the space station is controlled to be constant regardless of the beam direction and the number of beams. is there.
[0013]
Further, a wireless transmission device mounted on a mobile object, having a phased array antenna capable of controlling the beam direction, and performing wireless communication with a space station mounted on a satellite,
A transmitter for generating a high-frequency signal;
Moving body position / posture calculation means for calculating the position and posture of the moving body;
Space station position calculating means for calculating the position of the space station from the orbit information inputted in advance, and the mobile station and the space station based on the output of the moving body position and attitude calculating means and the output of the space station position calculating means. An antenna controller that calculates the distance and controls the beam direction of the phased array antenna, and a signal from the antenna controller transmits the transmission power input from the transmitter to the phased array antenna, using the beam direction of the phased array antenna and the moving object and space. Comprising a transmission power control device having a variable attenuator that controls according to the distance between stations,
When the beam direction is within a predetermined angle, the received electric field strength received by the space station is controlled to be constant irrespective of the beam direction and the distance between the moving object and the space station. .
[0014]
In addition, it has a plurality of phased array antennas mounted on a mobile object and arranged in different directions from each other and each beam direction can be controlled at a different angle from each other. A wireless transmission device that performs wireless communication in,
A transmitter for generating a high-frequency signal;
Moving body position and orientation calculating means for calculating the position and orientation of the moving body,
Space station position calculating means for calculating the position of the space station from orbit information input in advance,
Wherein on the basis of the outputs and the space station position calculating unit of the mobile position and orientation calculation unit, wherein each beam direction of the plurality of phased array antenna to calculate a distance between the moving body and the Space Administration An antenna controller for controlling in the direction of the space station ;
By the signal of the antenna controller, the transmission power from the transmitter to the phased array antenna in which the beam is directed to the space station, the phased array antenna in which the beam is directed to the space station, Number, each beam direction, comprising a transmission power control device having a plurality of variable attenuators to control according to the distance between the moving object and the space station,
When the space station is in a plurality of beam directing directions of the plurality of phased array antennas, the receiving electric field strength received by the space station is determined by the direction of the beam, the number of the beams , the moving object, and the moving object. It is controlled to be constant regardless of the distance to the space station.
[0015]
The moving object is an aircraft.
[0016]
The space station is a satellite station mounted on a satellite orbiting the earth.
[0017]
The satellite is a geostationary satellite.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 shows a configuration of a transmission power control device according to the present invention and a radio transmission device provided with the same. Reference numeral 1 denotes a transmitter mounted on an unillustrated mobile object, for example, an aircraft, for transmitting a signal to a satellite 4, and 2 denotes a transmitter 1. A phased array antenna for transmitting a signal to a satellite, 3 is a transmission wave described for explanation, 4 is a communication satellite (also referred to as a satellite station or space station) for performing this communication and is a geostationary satellite or a non-geostation. It does not matter whether the satellite is a satellite, but for convenience of explanation, it is described here as a geostationary satellite. Reference numeral 5 denotes an inertial navigation device (referred to as a moving body position / posture calculation unit) that outputs the position and attitude of an aircraft (not shown) on which the transmitter 1 is mounted on the earth, and 6 denotes an antenna control that controls a directional pattern of the phased array antenna 2. The orbital information 61 of the communication satellite 4 input in advance is stored in the storage device, and the current position of the satellite is calculated based on the orbital information 61 (referred to as space station position calculation means). The antenna controller 4 calculates and controls the beam direction of the phased array antenna 2 based on the output of the mobile object position / posture calculation means and the output of the space station position calculation means, and controls the earth station and the space station. Also calculate the distance between.
7 is a power amplifier for amplifying the output of the transmitter 1, 9 is a variable attenuator inserted between the transmitter 1 and the power amplifier 7, and can adjust the transmission power level by a signal from the antenna controller 6. it can.
The transmitter 1, the variable attenuator 9, the phased array antenna 2, the antenna controller 6, and the trajectory data 61 constitute a transmission power control device 100 according to the present invention.
The aircraft earth station 8 is a wireless transmission device according to the present invention.
[0019]
Next, the operation will be described.
As is well known, the phased array antenna 2 has a plurality of antenna elements arranged in a plane (not necessarily a plane), and each of the antenna elements is controlled in phase to be excited, so that the antenna element can emit radiation in an arbitrary direction (however, radiation (There may be directions that are not sufficient). In FIG. 1, the antenna controller 6 calculates the direction of the communication satellite based on the position and attitude data of the aircraft from the inertial navigation device 5 and the position data 61 of the communication satellite, controls the phased array antenna 2 and controls the communication satellite 4 Is controlled in the direction of.
[0020]
FIG. 2 shows the envelope 71 of the maximum gain when the direction of the beam controlled in this manner is changed. FIG. 2 is a diagram showing a change in gain when the beam direction of the phased array antenna 2 is changed from -90 degrees to +90 degrees. An angle of 0 degrees is in a direction orthogonal to the antenna surface, and an angle of 90 degrees is in the surface. The directions are parallel. As shown in FIG. 2, the gain characteristic of the phased array antenna 2 has a characteristic close to a cosine curve (depending on the shape of the antenna) because the apparent area of the antenna decreases as the distance from the direction perpendicular to the antenna surface decreases. The gain decreases.
The characteristic of FIG. 2 is represented as A (db) = kf (α).
Here, k is a constant.
The angle α is always output from the antenna controller 6 as a direction in which the communication satellite 4 is viewed from the aircraft (more precisely, from the plane of the phased array antenna).
[0021]
The output α of the antenna controller 6 is also output to the variable attenuator 9, and the variable attenuator 9 is controlled. Reference numeral 73 in FIG. 3 indicates a change in the gain characteristic of the variable attenuator 9 with respect to a change in the beam direction of the phased array antenna 2. The characteristic in FIG. 3 is set to B = −m / f (α) (db) in the range of −90 <α <+90. This characteristic is a characteristic that cancels the characteristic curve of the phased array antenna 2 in FIG.
However, when α is close to ± 90 degrees, f (α) becomes close to zero and B becomes infinitely large, so that a range that is not practical is generated. The angle range where the gain is stable is limited to about ± 85 degrees.
B <0 (db), and m is a constant.
As a result, the transmission power P transmitted from the phased array antenna 2 becomes P = mkf (α) / f (α) = mk (db), that is, within the range of −90 <α <+90. This is shown in FIG. Accordingly, the power density of the radio wave emitted toward the satellite is constant regardless of the change in the position and attitude of the aircraft equipped with the aircraft earth station 8 (however, as described above, α is within the range of ± 85 degrees). If the distance to the satellite 4 is substantially constant, the signal intensity received by the satellite 4 is always constant. As is well known, if the satellite 4 is a geostationary satellite, the distance is almost constant.
[0022]
In the configuration shown in FIG. 1, since a loop for feeding back from the communication satellite 4 to the earth station is not provided unlike the related art, there is no need to use a valuable transmission channel from the communication satellite for control. Is improved.
In addition, since a constant received signal electric field strength can always be secured, it is not necessary to set the signal strength with a margin more than necessary, and since the signal level can be set to the minimum necessary level, it interferes with other stations and interferes with other stations. The likelihood of interfering with other communications is also reduced.
[0023]
Embodiment 2 FIG.
In the description of the first embodiment, the case where the communication satellite 4 is at a direction of 85 degrees or more from the plane of the phased array antenna 2 is not described. Obviously, it is not necessary to consider the case where the position of the satellite is below the horizon. However, depending on the attitude of the aircraft, it may be necessary to deal with a direction exceeding the 85-degree direction of the phased array antenna 2.
In general, as shown in FIG. 5, two or more communication phased array antennas 2 mounted on an aircraft are arranged, for example, on both sides of the fuselage in different directions, and are switched and used as needed. The figure is a view of the aircraft viewed from the front, and the left and right indicate horizontal. The first and second antennas, not shown in the figure, are each arranged at an angle of 45 degrees in the opposite direction from directly above. 74 is an angle range covered by the first antenna, and 75 is an angle range covered by the second antenna.
[0024]
FIG. 6 shows a configuration of a transmission power control apparatus according to Embodiment 2 and a radio transmission apparatus using the same. In the figure, reference numeral 39 denotes a second variable attenuator, 37 denotes a second power amplifier, and 32 denotes a second phased array antenna. Here, 9, 7, and 2 are referred to as a first variable attenuator, a first power amplifier, and a first phased array antenna, respectively.
Switching between the first and second antennas is performed by the antenna controller 6 by interrupting the power supply to the antenna element of one of the antennas (by the variable attenuator 6 or 36). The range of about 85 degrees directly above can be accommodated by the first and second antennas, and even if both antennas are used (considering mutual phases). Good.
FIG. 7 shows that both antennas are used simultaneously on both sides of the angle range of 0 degree (-45 degrees to +45 degrees), and as the angle becomes larger, the transmission power of one of the antennas is gradually reduced, thereby causing a switching shock. It shows how to avoid using it. The vertical axis in FIG. 7 indicates the attenuation level of the variable attenuator 9.
The transmitter 1, the variable attenuators 9 and 39, the phased array antennas 2 and 32, the antenna controller 6 and the orbit data 61 constitute a transmission power control device 100 according to the present invention.
The aircraft earth station 8 is a wireless transmission device according to the present invention.
With this configuration, it is possible to respond to a satellite in any position that is visible in the whole sky, regardless of the attitude of the aircraft, within a controllable angle range.
[0025]
Embodiment 3 FIG.
As is well known, the electric field strength of a radio wave radiated at a certain spread angle is attenuated by the square of the distance.
If the satellite is a geostationary satellite, no significant change in distance occurs when the earth station moves over the earth's surface. However, when the satellite is a non-geostationary satellite, and particularly in a low orbit, the difference in the distance due to the change in the position of the earth station becomes large (for example, several hundred km when near, and about 10,000 km when far). There is a case where the radio wave of the near earth station is too strong and the reception of the radio wave of the distant station becomes difficult.
[0026]
As described in the first embodiment, when the antenna controller 6 calculates the beam direction of the phased array antenna 2, it can also calculate the distance between the earth station and the satellite station at the same time. If the power is controlled in proportion to the (1/2) th power of the distance, the received electric field strength can be controlled more irrespective of the distance to the satellite. FIG. 8 shows an attenuation control amount [A · (distance) ^1/2 ] of the variable attenuator 9 with respect to a change in distance.
Mk on the vertical axis is the same as mk in FIG. 4 of the first embodiment.
When the gain correction based on the beam direction described in the first embodiment and the correction based on the distance described in the present embodiment are both performed, the change width of the gain becomes extremely wide, and there is a possibility that the variable attenuator 6 alone cannot cope. There is also. In such a case, the change width may be increased by using the amplification by the power amplifier 7 in FIG.
[0027]
In the above description, the moving object is described as an aircraft, but the same applies to a ship, a vehicle, or another artificial satellite. Further, the satellite station is not limited to a geostationary satellite or a non-geostationary satellite, but is not necessarily limited to a satellite that orbits the earth, and may be a space station that continues to fly to another planet.
[0028]
【The invention's effect】
As described above, the transmission power control device of the present invention includes the variable attenuator that controls the transmission power according to the beam direction of the phased array antenna and the distance from the other space station. The received electric field strength can be kept constant irrespective of the position on the side and the position of the partner station . Also, transmission from the receiving side is not required.
[0030]
Also includes a plurality of different phased array antennas installation angle, toward a direction of each antenna in the direction of the same space station, more the number of antennas facing the space station direction and orientation of each antenna, each phased array Since the input of the antenna is controlled, the received electric field intensity at the space station can be kept constant irrespective of the angle of the beam even when the posture of the moving body changes at a wide angle.
[0031]
In addition to the control based on the beam angle, control based on the distance between the satellite and the earth station is also used. The electric field strength can be made constant.
[0032]
In addition, among a plurality of phased array antennas with different installation angles, the input of the antenna that could be directed in the direction of the space station , , The received electric field intensity at the space station can be kept constant even when the posture of the moving object changes over a wide angle and the distance changes .
[0033]
Further, the wireless transmission device is mounted on an aircraft, and can keep the received electric field strength at the satellite constant even when the attitude change angle is large.
[0034]
Further, the satellite is a satellite orbiting the earth, and the received electric field intensity at the satellite can be kept constant even if the distance changes greatly.
[0035]
Further, since the satellite is a geostationary satellite, the change in distance is small and the received electric field strength at the satellite can be kept constant.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a transmission power control device and a wireless transmission device using the same according to a first embodiment of the present invention.
FIG. 2 is a characteristic diagram of the phased array antenna of FIG.
FIG. 3 is an explanatory diagram of characteristics of the variable attenuator of FIG. 1;
FIG. 4 is an explanatory diagram of a received electric field strength at a satellite by the device of FIG. 1;
FIG. 5 is a characteristic diagram of a transmission power control device according to a second embodiment.
FIG. 6 is a configuration diagram of a transmission power control device according to a second embodiment and a wireless transmission device using the same.
FIG. 7 is an explanatory diagram of antenna power in the case of the characteristic of FIG. 5;
FIG. 8 is an explanatory diagram of transmission power control characteristics depending on distance according to the third embodiment.
FIG. 9 is a configuration diagram of a conventional transmission power control device.
[Explanation of symbols]
1 transmitter, 2 antennas or phased array antenna,
4 communication satellite, 5 inertial navigation system, 6 antenna controller,
7 Power amplifier, 8 Aircraft earth station (radio transmitter)
9 Variable attenuator, 61 Orbit data of communication satellite 100 Transmission power control device.

Claims

A transmission power control device mounted on a mobile body and controlling the electric field intensity of a radio wave reaching a space station to be constant,
A transmitter that generates a high-frequency signal,
A phase and array antenna having a plurality of element antennas and radiating the output of the transmitter,
Moving body position and orientation calculating means for calculating the position and orientation of the moving body,
Space station position calculating means for calculating the position of the space station from orbit information input in advance,
Based on the output of the moving body position and orientation calculating means and the output of the space station position calculating means, calculate the distance between the moving body and the space station, and control the excitation phase of the element antenna to An antenna controller for controlling the beam direction of a phased array antenna,
A variable attenuator that is inserted between the transmitter and the phased array antenna and attenuates the output of the transmitter according to the beam direction and the distance between the moving object and the space station by a signal of the antenna controller ; A transmission power control device comprising:

It has a plurality of phased array antennas mounted on a mobile object, arranged in different directions, and each beam direction can be controlled at different angles, and wirelessly communicates with a space station mounted on a satellite. A wireless transmission device that performs communication,
A transmitter for generating a high-frequency signal;
Moving body position and orientation calculating means for calculating the position and orientation of the moving body,
Space station position calculating means for calculating the position of the space station from orbit information input in advance,
An antenna controller that controls the beam directions of the plurality of phased array antennas in the direction of the space station, based on the output of the moving object position / posture calculation means and the output of the space station position calculation means,
By the signal of the antenna controller, the transmission power from the transmitter to the phased array antenna in which the beam is directed to the space station, the phased array antenna in which the beam is directed to the space station , A transmission power control device having a plurality and a plurality of variable attenuators each controlling according to the number and each beam direction,
When the space station is in the directional directions of the plurality of beams of the plurality of phased array antennas, the received electric field strength received by the space station is controlled to be constant regardless of the beam direction and the number of beams. A wireless transmission device characterized by the following.

A wireless transmission device mounted on a mobile object, having a phased array antenna capable of controlling the beam direction, and performing wireless communication with a space station mounted on a satellite,
A transmitter for generating a high-frequency signal;
Moving body position and orientation calculating means for calculating the position and orientation of the moving body,
Space station position calculating means for calculating the position of the space station from orbit information input in advance,
Antenna control for calculating a distance between the moving object and the space station and controlling a beam direction of the phased array antenna based on an output of the moving object position / posture calculating means and an output of the space station position calculating means. Vessels,
A variable attenuator that controls transmission power input from the transmitter to the phased array antenna according to a signal of the antenna controller according to a beam direction of the phased array antenna and a distance between the moving object and the space station. And a transmission power control device having
When the beam direction is within a predetermined angle, the received electric field strength received by the space station is constant regardless of the beam direction, and the distance between the moving object and the space station. A wireless transmission device characterized by controlling.

It has a plurality of phased array antennas mounted on a mobile object, arranged in different directions, and each beam direction can be controlled at different angles, and wirelessly communicates with a space station mounted on a satellite. A wireless transmission device that performs communication,
A transmitter for generating a high-frequency signal;
Moving body position and orientation calculating means for calculating the position and orientation of the moving body,
Space station position calculating means for calculating the position of the space station from orbit information input in advance,
Wherein on the basis of the outputs and the space station position calculating unit of the mobile position and orientation calculation unit, wherein each beam direction of the plurality of phased array antenna to calculate a distance between the moving body and the Space Administration An antenna controller for controlling in the direction of the space station ;
By the signal of the antenna controller, the transmission power from the transmitter to the phased array antenna in which the beam is directed to the space station, the phased array antenna in which the beam is directed to the space station, Number, each beam direction, comprising a transmission power control device having a plurality of variable attenuators to control according to the distance between the moving object and the space station,
When the space station is in a plurality of beam directing directions of the plurality of phased array antennas, the receiving electric field strength received by the space station is determined by the direction of the beam, the number of the beams , the moving object, and the moving object. A wireless transmission device characterized by constant control regardless of the distance to a space station.

The radio transmission apparatus according to claim 2, wherein the plurality of phased array antennas are arranged in directions different from each other by 90 degrees.

The wireless transmission device according to claim 3, wherein the transmission power control device controls the transmission power in proportion to a half power of the distance.

The wireless transmission device according to claim 1, wherein the moving object is an aircraft.

The radio transmitting apparatus according to any one of claims 1 to 7, wherein the space station is a satellite station mounted on a satellite orbiting the earth.

The wireless transmission device according to claim 8, wherein the satellite is a geostationary satellite.