JP2004140617A - Communication device and method therefor - Google Patents

Communication device and method therefor Download PDF

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JP2004140617A
JP2004140617A JP2002303723A JP2002303723A JP2004140617A JP 2004140617 A JP2004140617 A JP 2004140617A JP 2002303723 A JP2002303723 A JP 2002303723A JP 2002303723 A JP2002303723 A JP 2002303723A JP 2004140617 A JP2004140617 A JP 2004140617A
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satellite
artificial satellite
artificial
communication antenna
transmission
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JP4180345B2 (en
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Nobuyasu Takemura
竹村　暢康
Yoshihiko Konishi
小西　善彦
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a satellite communication system enabling stable communication and calls free from gain reduction, when switching from a 1st artificial satellite to a 2nd artificial satellite. <P>SOLUTION: An antenna 5 for satellite communication is directed toward a 1st artificial satellite 2 before the 1st artificial satellite 2 and a 2nd artificial satellite 3 will arrive at a handover point. A directed direction of the antenna 5 is controlled so as to make a transmitting/receiving level of the antenna 5 against the 1st artificial satellite 2 equal to that of the antenna 5 against the 2nd artificial satellite 3, when the 1st and 2nd artificial satellites 2, 3 arrive at the handover point. The handover from the 1st artificial satellite 2 to the 2nd artificial satellite 3 in a state that the transmitting/receiving level of the antenna 5 against the 1st artificial satellite 2 is equal to that of the antenna 5 against the 2nd artificial satellite 3. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、衛星を用いた通信技術に関するものである。
【０００２】
【従来の技術】
図６に例として従来の衛星通信における縦軸を地球上から見た仰角、横軸を時間としたときの人工衛星の衛星軌道の軌跡および衛星通信用アンテナのビーム指向性の軌跡を示す。
図において１３は第１の人工衛星の衛星軌道の軌跡、１４は第２の人工衛星の衛星軌道の軌跡、１６は第１の人工衛星から第２の人工衛星に切り替える（ハンドオーバ）時の第１の人工衛星の位置、１７はハンドオーバ時の第２の人工衛星の位置である。
図７は例として従来のハンドオーバ時の衛星通信用アンテナの主ビーム形状と人工衛星の方向を示した図である。
図において、４は衛星通信用送受信装置、５は衛星通信用アンテナ、１８は衛星通信用アンテナ５の主ビーム、２１は従来のハンドオーバ時の第１の人工衛星の方向、２２は従来のハンドオーバ時の第２の人工衛星の方向である。
【０００３】
次に動作について説明する。
楕円軌道上を周回する第１の人工衛星と第２の人工衛星は衛星軌道上の遠地点と近地点の間でハンドオーバする。
衛星通信用アンテナ５のビーム指向性は第１の人工衛星を追尾し、ハンドオーバ時に第１の人工衛星から第２の人工衛星に信号が切り替わる。ハンドオーバ後、衛星通信用アンテナ５のビーム指向性は第２の人工衛星を追尾する。
図７の衛星通信用アンテナ５のビーム形状を用いて説明すると、ハンドオーバ時には衛星通信用アンテナ５のビーム指向性は第１の人工衛星の方向２１がピーク方向となり、第２の人工衛星の方向２２はピークから外れた方向となる。そして、ハンドオーバ後に第２の人工衛星の方向にピークをもっていく。
【０００４】
なお、人工衛星を切り替えて使用するシステムは、例えば特開２００１−１１１４６９、特開２００１−３１３５９９号公報に記載されている。
【０００５】
【特許文献１】
特開２００１−１１１４６９号公報
【特許文献２】
特開２００１−３１３５９９号公報
【０００６】
【発明が解決しようとする課題】
従来の複数の人工衛星を用いた衛星通信システムにおける衛星間のハンドオーバ時には第１の人工衛星と第２の人工衛星の方向が異なるため、衛星通信用アンテナの送受信レベルに差異が生じる。
すなわち、第１の人工衛星から第２の人工衛星に切り替わったときに利得低下が生じ、通信・通話が途切れやすいあるいは着信しづらいという問題があった。
【０００７】
この発明は上記のような問題点を解決するためになされたもので、第１の人工衛星から第２の人工衛星に切り替わる際に利得低下が生じず、安定した通信・通話を可能とする衛星通信システムを実現することを目的とする。
【０００８】
【課題を解決するための手段】
本発明に係る地上通信装置は、所定の衛星軌道を周回する第１の人工衛星及び第１の人工衛星の衛星軌道と異なる衛星軌道を周回する第２の人工衛星と送受信するための衛星通信アンテナを備え、所定のハンドオーバ位置で第１の人工衛星から第２の人工衛星へのハンドオーバを行う地上通信装置であって、
第１の人工衛星から第２の人工衛星へのハンドオーバ時における第１の人工衛星に対する衛星通信アンテナの送受信レベルと第２の人工衛星に対する衛星通信アンテナの送受信レベルとが近づく方向に衛星通信アンテナの指向方向を制御するビーム制御手段を備えたことを特徴とする。
【０００９】
【発明の実施の形態】
実施の形態１．
図１は本実施の形態に係る衛星通信システムの通信対象とする人工衛星の２４時間周期の衛星軌道の例を示した図である。
図において、１は基準時刻から１日間に亘っての衛星軌道の地上軌跡である。図２は実施の形態１による衛星間ハンドオーバ時の衛星通信用アンテナのビーム方向を示した概略図である．
図において、２は第１の人工衛星、３は第２の人工衛星、４は衛星通信用送受信装置、５は衛星通信用アンテナ、６は衛星通信用アンテナのビーム指向性、７は第１の人工衛星２の軌道例、８は第２の人工衛星３の軌道例、９は地球、１０は衛星通信用アンテナ５のビーム指向性の軌跡、２３はビーム制御手段としてのビーム制御装置である。なお、衛星通信用送受信装置、衛星通信用アンテナ５、ビーム制御装置２３を合わせたものが、地上通信装置の例に相当する。
【００１０】
次に動作について説明する。
楕円軌道上を周回する第１の人工衛星２と第２の人工衛星３は衛星軌道上の遠地点と近地点の間でハンドオーバする。
第１の人工衛星２及び第２の人工衛星３のそれぞれがハンドオーバ位置の手前の所定位置に達するまでは、衛星通信用アンテナ５のビーム指向性６は第１の人工衛星２を追尾し、第１の人工衛星２と第２の人工衛星３とがハンドオーバ位置の手前の所定位置に達した際に衛星通信用アンテナ５のビーム指向性６を第１の人工衛星２からずらし、ハンドオーバ位置に達した際の第１の人工衛星に対する送受信レベルと第２の人工衛星に対する送受信レベルとが同等となるように衛星通信用アンテナ５の指向方向を制御する。
衛星通信用アンテナ５の指向方向の制御は、ビーム制御装置２３が行う。
ビーム制御装置２３は、例えば、第１の人工衛星の衛星軌道及び第２の人工衛星の衛星軌道を記憶しており、記憶している第１の人工衛星の衛星軌道及び第２の人工衛星の衛星軌道に基づきハンドオーバ位置を計算し、衛星通信用アンテナ５の指向方向の制御を行う。
【００１１】
以上のように、衛星通信用アンテナ５のビーム指向性６はハンドオーバ位置に達する前は第１の人工衛星２を追尾し、第１の人工衛星２と第２の人工衛星３とがハンドオーバ位置に達した際に第１の人工衛星に対する送受信レベルと第２の人工衛星に対する送受信レベルが同等となるように衛星通信用アンテナ５の指向方向を制御し、ハンドオーバ後に第２の人工衛星３を追尾するようにビーム指向性６を制御することにより、衛星通信用アンテナの送受信レベル低下を抑制できる。
【００１２】
実施の形態２．
図３は実施の形態２による衛星通信システムの通信対象となる人工衛星の衛星軌道の軌跡の例および衛星通信用アンテナのビーム指向性の軌跡の例を示した図である。
図において、１１は人工衛星の衛星軌道の軌跡の例、１２は衛星通信用アンテナのビーム指向性の軌跡の例である。図３では、説明のため人工衛星の衛星軌道の軌跡１１と衛星通信用アンテナのビーム指向性の軌跡は分離しているが、実際の運用では両者は重複する。
図４は縦軸を地球上から見た仰角、横軸を時間としたときの人工衛星の衛星軌道の軌跡の例および衛星通信用アンテナのビーム指向性の軌跡の例を示した図である。
図において１３は第１の人工衛星の衛星軌道の軌跡の例、１４は第２の人工衛星の衛星軌道の軌跡の例、１５は衛星通信用アンテナのビーム指向性の軌跡の例、１６はハンドオーバ時の第１の人工衛星の位置、１７はハンドオーバ時の第２の人工衛星の位置である。
図５は衛星通信用アンテナ５の主ビーム形状を示した図である。
図において、１８は衛星通信用アンテナ５の主ビーム、１９はハンドオーバ時の第１の人工衛星２の方向、２０はハンドオーバ時の第２の人工衛星３の方向、２１は従来のハンドオーバ時の第１の人工衛星２の方向、２２は従来のハンドオーバ時の第２の人工衛星３の方向である。
【００１３】
次に動作について説明する。
楕円軌道上を周回する第１の人工衛星２と第２の人工衛星３は衛星軌道上の遠地点と近地点の間でハンドオーバする。
第１の人工衛星２は衛星軌道上の遠地点からハンドオーバ位置まで周回し、第２の人工衛星３は衛星軌道上の近地点からハンドオーバ位置まで周回するとき、衛星通信用アンテナ５の指向方向を、ハンドオーバ時（第１の人工衛星２と第２の人工衛星３とがそれぞれハンドオーバする位置に達した際）に第１の人工衛星２の方向と第２の人工衛星３の方向のほぼ中間になるように第１の人工衛星２の方向から徐々にずらしていく。そして、衛星通信用アンテナ５の指向方向はハンドオーバ時に第１の人工衛星２の方向と第２の人工衛星３の方向のほぼ中間になる。ハンドオーバ後には第２の人工衛星を追尾するように衛星通信用アンテナ５のビーム指向性６を制御する。
図５の衛星通信用アンテナ５のビーム形状を用いて説明すると、ハンドオーバ時に衛星通信用アンテナ５のビーム指向性６を第１の人工衛星２の方向１９と第２の人工衛星３の方向２０のほぼ中間に向けることにより、第１の人工衛星に対する衛星通信用アンテナ５の送受信レベルと第２の人工衛星に対する衛星通信用アンテナ５の送受信レベルを同等とし、第１の人工衛星に対する送受信レベルと第２の人工衛星に対する送受信レベルとが同等の状態でハンドオーバを行うことができる。
つまり、第１の人工衛星２及び第２の人工衛星３がそれぞれハンドオーバ位置に達する前に衛星通信用アンテナ５の指向方向を制御して第１の人工衛星に対する衛星通信用アンテナ５の送受信レベルを次第に低下させるとともに第２の人工衛星に対する衛星通信用アンテナ５の送受信レベルを次第に上昇させ、第１の人工衛星２及び第２の人工衛星３がそれぞれハンドオーバ位置に達する際の第１の人工衛星に対する送受信レベルと第２の人工衛星に対する送受信レベルとが同等となるようにする。こうして、第１の人工衛星に対する送受信レベルと第２の人工衛星に対する送受信レベルとが同等の状態でハンドオーバを行うことができる。
【００１４】
以上のように、衛星通信用アンテナ５のビーム指向性６がハンドオーバ時に第１の人工衛星２の方向と第２の人工衛星３の方向のほぼ中間になるように第１の人工衛星２の方向から徐々にずらしていくようにビーム指向性６を制御することにより衛星通信用アンテナ５の送受信レベル低下を抑制できる。
【００１５】
実施の形態３．
実施の形態２では衛星通信用アンテナ５のビーム指向性６を第１の人工衛星２の方向から徐々にずらしていき、ハンドオーバ時に第１の人工衛星２の方向と第２の人工衛星３の方向のほぼ中間になるようにビーム指向性６を制御していたが、ハンドオーバの直前に衛星通信用アンテナ５のビーム指向性６を第１の人工衛星２の方向からずらし、ハンドオーバ時に第１の人工衛星２の方向と第２の人工衛星３の方向のほぼ中間になるようにビーム指向性６を制御することにより同様の効果が得られる。
つまり、第１の人工衛星２及び第２の人工衛星３がそれぞれハンドオーバ位置に達する直前に衛星通信用アンテナ５の指向方向を制御して第１の人工衛星に対する衛星通信用アンテナ５の送受信レベルを低下させるとともに第２の人工衛星に対する衛星通信用アンテナ５の送受信レベルを上昇させ、第１の人工衛星２及び第２の人工衛星３がそれぞれハンドオーバ位置に達する際の第１の人工衛星に対する送受信レベルと第２の人工衛星に対する送受信レベルとが同等となるようにする。こうして、第１の人工衛星に対する送受信レベルと第２の人工衛星に対する送受信レベルとが同等の状態でハンドオーバを行うことができる。
なお、ここで、ハンドオーバの直前とは、例えば、ハンドオーバの１分前である。
【００１６】
以上のように、衛星通信用アンテナ５のビーム指向性６をハンドオーバの直前に第１の人工衛星２の方向からずらし、ハンドオーバ時に第１の人工衛星２の方向と第２の人工衛星３の方向のほぼ中間になるように制御することにより衛星通信用アンテナ５の送受信レベル低下を抑制できる。
【００１７】
なお、実施の形態１〜３では、図１に示す８の字形状の衛星軌道を有する人工衛星を例として説明したが、本発明は他の種類の衛星軌道を有する人工衛星にも適用可能である。どのような衛星軌道であっても、複数の人工衛星の間でハンドオーバが行われるのであれば、本発明は適用することができる。
また実施の形態１〜３では、ハンドオーバ時の第１の人工衛星２の方向と第２の人工衛星３の方向のほぼ中間位置を目標として、衛星通信用アンテナ５のビーム指向性６を制御するものを示したが、これは上記中間位置が最も効率的な位置である例を示したものであり、上記中間位置でなくとも、第１の人工衛星２の送受信レベルと第２の人工衛星３の送受信レベルが同等になるような位置を目標に制御し、その地点でハンドオーバさせることで、ハンドオーバ時の送受信レベルの急な変化を抑えることができる。
【００１８】
ここで、実施の形態１〜３に示した衛星通信システム及び衛星通信方法の特徴を以下にて再言する。
【００１９】
実施の形態１に係る衛星通信システムは、複数の非静止軌道上を周回する通信系を備えた複数の人工衛星が１つの軌道に一機ずつ配置され、
前記人工衛星を介した衛星通信を行なうための地上側の衛星通信用送受信装置と衛星通信用アンテナを少なくとも備え、
前記人工衛星と前記衛星通信用アンテナとの間で通信あるいは放送が行なわれるための衛星通信システムであって、
利用する前記人工衛星の第１の人工衛星を第２の人工衛星に切り替える際に、
前記衛星通信用アンテナのビーム指向性を前記人工衛星の第１の人工衛星からずらし、
前記衛星通信用アンテナにおける送受信レベルを、前記人工衛星の第１の人工衛星と第２の人工衛星とほぼ同じ送受信レベルで切り替え、
前記人工衛星の第１の人工衛星を第２の人工衛星に切り替えた後に第２の人工衛星を追尾するようにビーム制御することを特徴とする。
【００２０】
実施の形態２に係る衛星通信システムは、上記人工衛星の第１の人工衛星が軌道上の近地点にあるときから、
利用する上記人工衛星の第１の人工衛星を第２の人工衛星に切り替えるまでの間に、
上記衛星通信用アンテナのビーム指向性を前記第１の人工衛星から徐々にずらしていき、
前記衛星通信用アンテナにおける送受信レベルを、前記人工衛星の第１の人工衛星と第２の人工衛星とほぼ同じ送受信レベルで切り替え、
前記人工衛星の第１の人工衛星を第２の人工衛星に切り替えた後に第２の人工衛星を追尾するようにビーム制御することを特徴とする。
【００２１】
実施の形態３に係る衛星通信システムは、上記人工衛星の第１の人工衛星を第２の人工衛星に切り替える直前において、
衛星通信用アンテナのビーム指向性を上記第１の人工衛星からずらし、
前記衛星通信用アンテナにおける送受信レベルを、前記人工衛星の第１の人工衛星と第２の人工衛星とほぼ同じ送受信レベルで切り替え、
前記人工衛星の第１の人工衛星を第２の人工衛星に切り替えた後に第２の人工衛星を追尾するようにビーム制御することを特徴とする。
【００２２】
実施の形態１に係る衛星通信方法は、複数の非静止軌道上を周回する通信系を備えた複数の人工衛星が１つの軌道に一機ずつ配置され、
前記人工衛星を介した衛星通信を行なうための地上側の衛星通信用送受信装置およびビーム制御装置と衛星通信用アンテナを少なくとも備え、
前記人工衛星と前記衛星通信用アンテナとの間で通信あるいは放送が行なわれるための衛星通信システムにおいて、
利用する前記人工衛星の第１の人工衛星を第２の人工衛星に切り替える際に、
前記衛星通信用アンテナのビーム指向性を前記人工衛星の第１の人工衛星からずらし、
前記衛星通信用アンテナにおける送受信レベルを、前記人工衛星の第１の人工衛星と第２の人工衛星とほぼ同じ送受信レベルで切り替え、
前記人工衛星の第１の人工衛星を第２の人工衛星に切り替えた後に第２の人工衛星を追尾するようにビーム制御することを特徴とする。
【００２３】
実施の形態２に係る衛星通信方法は、上記人工衛星の第１の人工衛星が軌道上の近地点にあるときから、
利用する上記人工衛星の第１の人工衛星を第２の人工衛星に切り替えるまでの間に、
上記衛星通信用アンテナのビーム指向性を前記第１の人工衛星から徐々にずらしていき、
前記衛星通信用アンテナにおける送受信レベルを、前記人工衛星の第１の人工衛星と第２の人工衛星とほぼ同じ送受信レベルで切り替え、
前記人工衛星の第１の人工衛星を第２の人工衛星に切り替えた後に第２の人工衛星を追尾するようにビーム制御することを特徴とする。
【００２４】
実施の形態３に係る衛星通信方法は、上記人工衛星の第１の人工衛星を第２の人工衛星に切り替える直前において、
衛星通信用アンテナのビーム指向性を上記第１の人工衛星からずらし、
前記衛星通信用アンテナにおける送受信レベルを、前記人工衛星の第１の人工衛星と第２の人工衛星とほぼ同じ送受信レベルで切り替え、
前記人工衛星の第１の人工衛星を第２の人工衛星に切り替えた後に第２の人工衛星を追尾するようにビーム制御することを特徴とする。
【００２５】
【発明の効果】
本発明によれば、第１の人工衛星に対する衛星通信アンテナの送受信レベルを、ハンドオーバ時の第２の人工衛星に対する衛星通信アンテナの送受信レベルに近づけるため、ハンドオーバ時の送受信レベルの急な変化が生じず、安定した通信・通話を実現することができる。
【図面の簡単な説明】
【図１】人工衛星の衛星軌道の軌跡例を示す図。
【図２】衛星通信用アンテナのビーム方向を示す概念図。
【図３】人工衛星の衛星軌道の軌跡例及びビーム指向性の軌跡例を示す図。
【図４】人工衛星の衛星軌道の軌跡例及びビーム指向性の軌跡例を示す図。
【図５】衛星通信用アンテナの主ビーム形状を示す図。
【図６】従来の人工衛星の衛星軌道の軌跡例及びビーム指向性の軌跡例を示す図。
【図７】従来の衛星通信用アンテナの主ビーム形状を示す図。
【符号の説明】
１　人工衛星の衛星軌道の軌跡、２　第１の人工衛星、３　第２の人工衛星、４　衛星通信用送受信装置、５　衛星通信用アンテナ、６　衛星通信用アンテナのビーム指向性、７　第１の人工衛星の軌跡、８　第２の人工衛星の軌跡、９　地球、１０　衛星通信用アンテナのビーム指向性の軌跡、２３　ビーム制御装置。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication technology using a satellite.
[0002]
[Prior art]
FIG. 6 shows, by way of example, the trajectory of the satellite orbit of the artificial satellite and the trajectory of the beam directivity of the satellite communication antenna when the vertical axis represents the elevation angle as viewed from the earth and the horizontal axis represents time in conventional satellite communication.
In the figure, 13 is the trajectory of the satellite orbit of the first artificial satellite, 14 is the trajectory of the satellite orbit of the second artificial satellite, and 16 is the first at the time of switching from the first artificial satellite to the second artificial satellite (handover). Is the position of the second artificial satellite, and 17 is the position of the second artificial satellite at the time of handover.
FIG. 7 is a diagram showing, as an example, a main beam shape of a satellite communication antenna and a direction of an artificial satellite at the time of a conventional handover.
In the figure, 4 is a transmitting / receiving device for satellite communication, 5 is a satellite communication antenna, 18 is the main beam of the satellite communication antenna 5, 21 is the direction of the first artificial satellite at the time of conventional handover, and 22 is the direction of the conventional handover. In the direction of the second satellite.
[0003]
Next, the operation will be described.
The first satellite and the second satellite orbiting in an elliptical orbit hand over between apogee and perigee in the satellite orbit.
The beam directivity of the satellite communication antenna 5 tracks the first artificial satellite, and the signal is switched from the first artificial satellite to the second artificial satellite during handover. After the handover, the beam directivity of the satellite communication antenna 5 tracks the second artificial satellite.
To explain using the beam shape of the satellite communication antenna 5 in FIG. 7, the beam directivity of the satellite communication antenna 5 at the time of handover is such that the direction 21 of the first artificial satellite has a peak direction and the direction 22 of the second artificial satellite has a peak direction. Is a direction deviating from the peak. Then, after the handover, a peak is made in the direction of the second artificial satellite.
[0004]
In addition, the system which switches and uses an artificial satellite is described in Unexamined-Japanese-Patent No. 2001-111469 and 2001-313599, for example.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2001-111469 [Patent Document 2]
JP 2001-313599 A
[Problems to be solved by the invention]
At the time of handover between satellites in a conventional satellite communication system using a plurality of artificial satellites, the directions of the first artificial satellite and the second artificial satellite are different, so that the transmission / reception level of the satellite communication antenna differs.
In other words, when switching from the first artificial satellite to the second artificial satellite, a decrease in gain occurs, and there is a problem that communication / communication is easily interrupted or an incoming call is hardly received.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a satellite that enables stable communication and communication without a decrease in gain when switching from a first artificial satellite to a second artificial satellite. It is intended to realize a communication system.
[0008]
[Means for Solving the Problems]
A terrestrial communication apparatus according to the present invention is a satellite communication antenna for transmitting and receiving to and from a first artificial satellite orbiting a predetermined satellite orbit and a second artificial satellite orbiting a satellite orbit different from the satellite orbit of the first artificial satellite. A terrestrial communication apparatus that performs handover from a first artificial satellite to a second artificial satellite at a predetermined handover position,
At the time of handover from the first artificial satellite to the second artificial satellite, the transmission / reception level of the satellite communication antenna with respect to the first artificial satellite and the transmission / reception level of the satellite communication antenna with respect to the second artificial satellite approach each other. A beam control means for controlling the directivity direction is provided.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a diagram showing an example of a satellite orbit in a 24-hour cycle of an artificial satellite to be communicated by the satellite communication system according to the present embodiment.
In the figure, reference numeral 1 denotes a trajectory of the satellite orbit over a one-day period from the reference time. FIG. 2 is a schematic diagram showing a beam direction of a satellite communication antenna at the time of handover between satellites according to the first embodiment.
In the figure, reference numeral 2 denotes a first artificial satellite, 3 denotes a second artificial satellite, 4 denotes a transmitting / receiving device for satellite communication, 5 denotes a satellite communication antenna, 6 denotes a beam directivity of the satellite communication antenna, and 7 denotes a first antenna. An orbital example of the artificial satellite 2, 8 is an orbital example of the second artificial satellite 3, 9 is the earth, 10 is a trajectory of the beam directivity of the satellite communication antenna 5, and 23 is a beam control device as beam control means. The combination of the satellite communication transmitting / receiving device, the satellite communication antenna 5, and the beam control device 23 corresponds to an example of the terrestrial communication device.
[0010]
Next, the operation will be described.
The first artificial satellite 2 and the second artificial satellite 3 orbiting in an elliptical orbit hand over between an apogee and a perigee in the satellite orbit.
Until each of the first artificial satellite 2 and the second artificial satellite 3 reaches a predetermined position before the handover position, the beam directivity 6 of the satellite communication antenna 5 tracks the first artificial satellite 2, When the first artificial satellite 2 and the second artificial satellite 3 reach a predetermined position before the handover position, the beam directivity 6 of the satellite communication antenna 5 is shifted from the first artificial satellite 2 to reach the handover position. The pointing direction of the satellite communication antenna 5 is controlled so that the transmission / reception level for the first artificial satellite and the transmission / reception level for the second artificial satellite are equal.
The beam controller 23 controls the directivity of the satellite communication antenna 5.
The beam control device 23 stores, for example, the satellite orbit of the first artificial satellite and the satellite orbit of the second artificial satellite, and stores the stored satellite orbit of the first artificial satellite and the stored satellite orbit of the second artificial satellite. The handover position is calculated based on the satellite orbit, and the pointing direction of the satellite communication antenna 5 is controlled.
[0011]
As described above, the beam directivity 6 of the satellite communication antenna 5 tracks the first artificial satellite 2 before reaching the handover position, and the first artificial satellite 2 and the second artificial satellite 3 move to the handover position. When reaching, the pointing direction of the satellite communication antenna 5 is controlled so that the transmission / reception level for the first artificial satellite becomes equal to the transmission / reception level for the second artificial satellite, and the second artificial satellite 3 is tracked after the handover. By controlling the beam directivity 6 as described above, it is possible to suppress a decrease in the transmission / reception level of the satellite communication antenna.
[0012]
Embodiment 2 FIG.
FIG. 3 is a diagram showing an example of a trajectory of a satellite orbit of an artificial satellite to be communicated by the satellite communication system according to the second embodiment and an example of a trajectory of a beam directivity of a satellite communication antenna.
In the figure, 11 is an example of the trajectory of the satellite orbit of the artificial satellite, and 12 is an example of the trajectory of the beam directivity of the satellite communication antenna. In FIG. 3, the trajectory 11 of the satellite orbit of the artificial satellite and the trajectory of the beam directivity of the satellite communication antenna are separated for the sake of explanation, but they overlap in actual operation.
FIG. 4 is a diagram showing an example of the trajectory of the satellite orbit of the artificial satellite and the trajectory of the beam directivity of the satellite communication antenna when the vertical axis is the elevation angle as viewed from the earth and the horizontal axis is time.
In the figure, 13 is an example of the trajectory of the satellite orbit of the first artificial satellite, 14 is an example of the trajectory of the satellite orbit of the second artificial satellite, 15 is an example of the trajectory of the beam directivity of the satellite communication antenna, and 16 is the handover. The position of the first satellite at time 17 is the position of the second satellite at handover.
FIG. 5 is a diagram showing a main beam shape of the satellite communication antenna 5.
In the figure, 18 is the main beam of the satellite communication antenna 5, 19 is the direction of the first artificial satellite 2 at the time of handover, 20 is the direction of the second artificial satellite 3 at the time of handover, and 21 is the second beam at the time of conventional handover. The direction of the first artificial satellite 2 and the direction 22 of the second artificial satellite 3 at the time of the conventional handover are shown.
[0013]
Next, the operation will be described.
The first artificial satellite 2 and the second artificial satellite 3 orbiting in an elliptical orbit hand over between an apogee and a perigee in the satellite orbit.
When the first artificial satellite 2 orbits from the apogee on the satellite orbit to the handover position, and the second artificial satellite 3 orbits from the perigee on the satellite orbit to the handover position, the pointing direction of the satellite communication antenna 5 is changed by handover. At the time (when the first artificial satellite 2 and the second artificial satellite 3 reach the handover positions, respectively), the direction of the first artificial satellite 2 and the direction of the second artificial satellite 3 are almost in the middle. Is gradually shifted from the direction of the first artificial satellite 2. The pointing direction of the satellite communication antenna 5 is substantially halfway between the direction of the first artificial satellite 2 and the direction of the second artificial satellite 3 during handover. After the handover, the beam directivity 6 of the satellite communication antenna 5 is controlled so as to track the second artificial satellite.
To explain using the beam shape of the satellite communication antenna 5 in FIG. 5, the beam directivity 6 of the satellite communication antenna 5 is changed between the direction 19 of the first artificial satellite 2 and the direction 20 of the second artificial satellite 3 at the time of handover. The transmission / reception level of the satellite communication antenna 5 with respect to the first artificial satellite is made equal to the transmission / reception level of the satellite communication antenna 5 with respect to the second artificial satellite, and the transmission / reception level with respect to the first artificial satellite and The handover can be performed in a state where the transmission and reception levels for the two artificial satellites are equivalent.
That is, before each of the first artificial satellite 2 and the second artificial satellite 3 reaches the handover position, the directivity direction of the satellite communication antenna 5 is controlled to change the transmission / reception level of the satellite communication antenna 5 with respect to the first artificial satellite. The transmission / reception level of the satellite communication antenna 5 with respect to the second artificial satellite is gradually decreased, and the transmission / reception level with respect to the first artificial satellite when the first artificial satellite 2 and the second artificial satellite 3 reach the handover position is gradually increased. The transmission / reception level is made equal to the transmission / reception level for the second artificial satellite. Thus, the handover can be performed with the transmission / reception level for the first artificial satellite and the transmission / reception level for the second artificial satellite being equal.
[0014]
As described above, the direction of the first artificial satellite 2 is set so that the beam directivity 6 of the satellite communication antenna 5 is substantially halfway between the direction of the first artificial satellite 2 and the direction of the second artificial satellite 3 during handover. By controlling the beam directivity 6 so as to gradually shift from the above, it is possible to suppress a decrease in the transmission / reception level of the satellite communication antenna 5.
[0015]
Embodiment 3 FIG.
In the second embodiment, the beam directivity 6 of the satellite communication antenna 5 is gradually shifted from the direction of the first artificial satellite 2, and the direction of the first artificial satellite 2 and the direction of the second artificial satellite 3 at the time of handover. The beam directivity 6 is controlled so as to be approximately in the middle of the first artificial satellite 2, but the beam directivity 6 of the satellite communication antenna 5 is shifted from the direction of the first artificial satellite 2 immediately before the handover, and the first artificial The same effect can be obtained by controlling the beam directivity 6 so as to be substantially intermediate between the direction of the satellite 2 and the direction of the second artificial satellite 3.
That is, immediately before each of the first artificial satellite 2 and the second artificial satellite 3 reaches the handover position, the pointing direction of the satellite communication antenna 5 is controlled so that the transmission / reception level of the satellite communication antenna 5 with respect to the first artificial satellite is changed. The transmission / reception level of the satellite communication antenna 5 with respect to the second artificial satellite is increased and the transmission / reception level with respect to the first artificial satellite when the first artificial satellite 2 and the second artificial satellite 3 each reach the handover position. And the transmission / reception level for the second artificial satellite are made equal. Thus, the handover can be performed with the transmission / reception level for the first artificial satellite and the transmission / reception level for the second artificial satellite being equal.
Here, immediately before the handover is, for example, one minute before the handover.
[0016]
As described above, the beam directivity 6 of the satellite communication antenna 5 is shifted from the direction of the first artificial satellite 2 immediately before the handover, and the direction of the first artificial satellite 2 and the direction of the second artificial satellite 3 during the handover. By controlling so as to be approximately halfway between the above, it is possible to suppress a decrease in the transmission / reception level of the satellite communication antenna 5.
[0017]
In the first to third embodiments, the artificial satellite having the eight-shaped satellite orbit illustrated in FIG. 1 has been described as an example, but the present invention is also applicable to artificial satellites having other types of satellite orbits. is there. The present invention can be applied to any satellite orbit as long as handover is performed between a plurality of artificial satellites.
Further, in the first to third embodiments, the beam directivity 6 of the satellite communication antenna 5 is controlled with a target substantially at an intermediate position between the direction of the first artificial satellite 2 and the direction of the second artificial satellite 3 at the time of handover. This is an example in which the intermediate position is the most efficient position. Even if the intermediate position is not the intermediate position, the transmission / reception level of the first artificial satellite 2 and the second artificial satellite 3 By controlling a target such that the transmission / reception level becomes the same and performing handover at that point, it is possible to suppress a sudden change in transmission / reception level at the time of handover.
[0018]
Here, the features of the satellite communication system and the satellite communication method shown in the first to third embodiments will be described again below.
[0019]
In the satellite communication system according to the first embodiment, a plurality of artificial satellites having a communication system orbiting on a plurality of non-geostationary orbits are arranged one by one in one orbit,
At least a terrestrial-side satellite communication transceiver and a satellite communication antenna for performing satellite communication via the artificial satellite,
A satellite communication system for performing communication or broadcasting between the artificial satellite and the satellite communication antenna,
When switching the first satellite of the satellite to be used to the second satellite,
Shifting the beam directivity of the satellite communication antenna from the first satellite of the satellite,
A transmission / reception level of the satellite communication antenna is switched at substantially the same transmission / reception level as that of the first artificial satellite and the second artificial satellite of the artificial satellite;
After switching the first artificial satellite of the artificial satellite to the second artificial satellite, beam control is performed so as to track the second artificial satellite.
[0020]
The satellite communication system according to the second embodiment starts when the first artificial satellite of the above-mentioned artificial satellite is located at a perigee in orbit.
Before switching the first satellite of the satellite to be used to the second satellite,
Gradually shifting the beam directivity of the satellite communication antenna from the first artificial satellite,
A transmission / reception level of the satellite communication antenna is switched at substantially the same transmission / reception level as that of the first artificial satellite and the second artificial satellite of the artificial satellite;
After switching the first artificial satellite of the artificial satellite to the second artificial satellite, beam control is performed so as to track the second artificial satellite.
[0021]
In the satellite communication system according to Embodiment 3, immediately before switching the first artificial satellite of the artificial satellite to the second artificial satellite,
Shifting the beam directivity of the satellite communication antenna from the first artificial satellite,
A transmission / reception level of the satellite communication antenna is switched at substantially the same transmission / reception level as that of the first artificial satellite and the second artificial satellite of the artificial satellite;
After switching the first artificial satellite of the artificial satellite to the second artificial satellite, beam control is performed so as to track the second artificial satellite.
[0022]
In the satellite communication method according to Embodiment 1, a plurality of artificial satellites having a communication system orbiting in a plurality of non-geostationary orbits are arranged one by one in one orbit,
At least a terrestrial-side satellite communication transceiver and a beam control device for performing satellite communication via the artificial satellite and a satellite communication antenna,
In a satellite communication system for performing communication or broadcasting between the artificial satellite and the satellite communication antenna,
When switching the first satellite of the satellite to be used to the second satellite,
Shifting the beam directivity of the satellite communication antenna from the first satellite of the satellite,
A transmission / reception level of the satellite communication antenna is switched at substantially the same transmission / reception level as that of the first artificial satellite and the second artificial satellite of the artificial satellite;
After switching the first artificial satellite of the artificial satellite to the second artificial satellite, beam control is performed so as to track the second artificial satellite.
[0023]
The satellite communication method according to the second embodiment starts at a time when the first artificial satellite of the above-mentioned artificial satellite is at a perigee in orbit.
Before switching the first satellite of the satellite to be used to the second satellite,
Gradually shifting the beam directivity of the satellite communication antenna from the first artificial satellite,
A transmission / reception level of the satellite communication antenna is switched at substantially the same transmission / reception level as that of the first artificial satellite and the second artificial satellite of the artificial satellite;
After switching the first artificial satellite of the artificial satellite to the second artificial satellite, beam control is performed so as to track the second artificial satellite.
[0024]
In the satellite communication method according to Embodiment 3, immediately before switching the first artificial satellite of the artificial satellite to the second artificial satellite,
Shifting the beam directivity of the satellite communication antenna from the first artificial satellite,
A transmission / reception level of the satellite communication antenna is switched at substantially the same transmission / reception level as that of the first artificial satellite and the second artificial satellite of the artificial satellite;
After switching the first artificial satellite of the artificial satellite to the second artificial satellite, beam control is performed so as to track the second artificial satellite.
[0025]
【The invention's effect】
According to the present invention, the transmission / reception level of the satellite communication antenna with respect to the first artificial satellite is made closer to the transmission / reception level of the satellite communication antenna with respect to the second artificial satellite at the time of handover. And stable communication and communication can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a trajectory of a satellite orbit of an artificial satellite.
FIG. 2 is a conceptual diagram showing a beam direction of a satellite communication antenna.
FIG. 3 is a diagram showing an example of a trajectory of a satellite orbit and a trajectory of a beam directivity of an artificial satellite.
FIG. 4 is a diagram illustrating an example of a trajectory of a satellite orbit and a trajectory of a beam directivity of an artificial satellite.
FIG. 5 is a diagram showing a main beam shape of a satellite communication antenna.
FIG. 6 is a diagram illustrating an example of a trajectory of a satellite orbit and a trajectory of beam directivity of a conventional artificial satellite.
FIG. 7 is a diagram showing a main beam shape of a conventional satellite communication antenna.
[Explanation of symbols]
1 trajectory of artificial satellite orbit, 2 first artificial satellite, 3 second artificial satellite, 4 satellite communication transceiver, 5 satellite communication antenna, 6 beam directivity of satellite communication antenna, 7 first Track of an artificial satellite, 8 track of a second satellite, 9 earth, 10 beam directivity of a satellite communication antenna, 23 beam control device.

Claims (6)

所定の衛星軌道を周回する第１の人工衛星及び第１の人工衛星の衛星軌道と異なる衛星軌道を周回する第２の人工衛星と送受信するための衛星通信アンテナを備え、所定のハンドオーバ位置で第１の人工衛星から第２の人工衛星へのハンドオーバを行う通信装置であって、
上記第１の人工衛星に対する衛星通信アンテナの送受信レベルが、ハンドオーバ時の第２の人工衛星に対する衛星通信アンテナの送受信レベルに近づく方向に衛星通信アンテナの指向方向を制御するビーム制御手段を備えた、
ことを特徴とする通信装置。A first artificial satellite orbiting a predetermined satellite orbit and a satellite communication antenna for transmitting and receiving to and from a second artificial satellite orbiting a satellite orbit different from the satellite orbit of the first artificial satellite; A communication device for performing handover from one artificial satellite to a second artificial satellite,
Beam control means for controlling the directivity of the satellite communication antenna so that the transmission / reception level of the satellite communication antenna with respect to the first artificial satellite approaches the transmission / reception level of the satellite communication antenna with respect to the second artificial satellite at the time of handover;
A communication device characterized by the above-mentioned. 上記ビーム制御手段は、
第１の人工衛星及び第２の人工衛星がそれぞれハンドオーバ位置に達する前に衛星通信アンテナの指向方向を制御して第１の人工衛星に対する衛星通信アンテナの送受信レベルを次第に低下させるとともに第２の人工衛星に対する衛星通信アンテナの送受信レベルを次第に上昇させ、第１の人工衛星及び第２の人工衛星がそれぞれハンドオーバ位置に達する際の第１の人工衛星に対する衛星通信アンテナの送受信レベルと第２の人工衛星に対する衛星通信アンテナの送受信レベルとを同等とすることを特徴とする請求項１に記載の通信装置。The beam control means,
Before the first artificial satellite and the second artificial satellite each reach the handover position, the pointing direction of the satellite communication antenna is controlled to gradually reduce the transmission / reception level of the satellite communication antenna with respect to the first artificial satellite and to reduce the second artificial satellite. The transmission / reception level of the satellite communication antenna with respect to the satellite is gradually increased, and the transmission / reception level of the satellite communication antenna with respect to the first satellite and the second satellite when the first artificial satellite and the second artificial satellite reach the handover position, respectively. 2. The communication apparatus according to claim 1, wherein a transmission / reception level of a satellite communication antenna with respect to the transmission level is equal. 上記ビーム制御手段は、
第１の人工衛星及び第２の人工衛星がそれぞれハンドオーバ位置に達する直前に衛星通信アンテナの指向方向を制御して第１の人工衛星に対する衛星通信アンテナの送受信レベルを低下させるとともに第２の人工衛星に対する衛星通信アンテナの送受信レベルを上昇させ、第１の人工衛星及び第２の人工衛星がそれぞれハンドオーバ位置に達する際の第１の人工衛星に対する衛星通信アンテナの送受信レベルと第２の人工衛星に対する衛星通信アンテナの送受信レベルとを同等とすることを特徴とする請求項１に記載の通信装置。The beam control means,
Immediately before each of the first artificial satellite and the second artificial satellite reaches the handover position, the directivity direction of the satellite communication antenna is controlled to reduce the transmission / reception level of the satellite communication antenna with respect to the first artificial satellite, and the second artificial satellite The transmission / reception level of the satellite communication antenna for the first artificial satellite and the satellite for the second artificial satellite when the first artificial satellite and the second artificial satellite each reach the handover position are increased. The communication device according to claim 1, wherein the transmission and reception levels of the communication antenna are made equal. 所定の衛星軌道を周回する第１の人工衛星及び第１の人工衛星の衛星軌道と異なる衛星軌道を周回する第２の人工衛星と送受信するための衛星通信アンテナを用い、所定のハンドオーバ位置で第１の人工衛星から第２の人工衛星へのハンドオーバを行う通信方法であって、
上記第１の人工衛星に対する衛星通信アンテナの送受信レベルが、ハンドオーバ時の第２の人工衛星に対する衛星通信アンテナの送受信レベルに近づく方向に衛星通信アンテナの指向方向を制御する、
ことを特徴とする通信方法。A first artificial satellite orbiting a predetermined satellite orbit and a satellite communication antenna for transmitting and receiving to and from a second artificial satellite orbiting a satellite orbit different from the satellite orbit of the first artificial satellite are used at a predetermined handover position. A communication method for performing handover from one artificial satellite to a second artificial satellite,
Controlling the pointing direction of the satellite communication antenna such that the transmission / reception level of the satellite communication antenna with respect to the first artificial satellite approaches the transmission / reception level of the satellite communication antenna with respect to the second artificial satellite at the time of handover;
A communication method, comprising: 上記通信方法は、
第１の人工衛星及び第２の人工衛星がそれぞれハンドオーバ位置に達する前に衛星通信アンテナの指向方向を制御して第１の人工衛星に対する衛星通信アンテナの送受信レベルを次第に低下させるとともに第２の人工衛星に対する衛星通信アンテナの送受信レベルを次第に上昇させ、第１の人工衛星及び第２の人工衛星がそれぞれハンドオーバ位置に達する際の第１の人工衛星に対する衛星通信アンテナの送受信レベルと第２の人工衛星に対する衛星通信アンテナの送受信レベルとを同等とすることを特徴とする請求項４に記載の通信方法。The above communication method,
Before the first artificial satellite and the second artificial satellite each reach the handover position, the pointing direction of the satellite communication antenna is controlled to gradually reduce the transmission / reception level of the satellite communication antenna with respect to the first artificial satellite and to reduce the second artificial satellite. The transmission / reception level of the satellite communication antenna with respect to the satellite is gradually increased, and the transmission / reception level of the satellite communication antenna with respect to the first satellite and the second satellite when the first artificial satellite and the second artificial satellite reach the handover position, respectively. 5. The communication method according to claim 4, wherein a transmission / reception level of a satellite communication antenna is set to be equal to the transmission / reception level. 上記通信方法は、
第１の人工衛星及び第２の人工衛星がそれぞれハンドオーバ位置に達する直前に衛星通信アンテナの指向方向を制御して第１の人工衛星に対する衛星通信アンテナの送受信レベルを低下させるとともに第２の人工衛星に対する衛星通信アンテナの送受信レベルを上昇させ、第１の人工衛星及び第２の人工衛星がそれぞれハンドオーバ位置に達する際の第１の人工衛星に対する衛星通信アンテナの送受信レベルと第２の人工衛星に対する衛星通信アンテナの送受信レベルとを同等とすることを特徴とする請求項４に記載の通信方法。The above communication method,
Immediately before each of the first artificial satellite and the second artificial satellite reaches the handover position, the directivity direction of the satellite communication antenna is controlled to reduce the transmission / reception level of the satellite communication antenna with respect to the first artificial satellite, and the second artificial satellite The transmission / reception level of the satellite communication antenna for the first artificial satellite and the satellite for the second artificial satellite when the first artificial satellite and the second artificial satellite each reach the handover position are increased. The communication method according to claim 4, wherein the transmission and reception levels of the communication antenna are made equal.
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JPS6113166A (en) * 1984-06-29 1986-01-21 Nec Corp Antenna tracking apparatus
JPS6488270A (en) * 1987-09-30 1989-04-03 Nec Corp Tracking system of moving-body antenna for moving-body satellite communication
JP2001111469A (en) * 1999-10-01 2001-04-20 Communication Research Laboratory Mpt Method for designing satellite orbit arrangement capable of switching satellite in same antenna beam and satellite system using the orbit
JP2001313599A (en) * 2000-04-28 2001-11-09 Hitachi Ltd Communication using non-geostationary satellite, or master side system or slave side unit for broadcast
JP2002124815A (en) * 2000-10-13 2002-04-26 Sony Corp Method and equipment for adjusting direction of multi- beam antenna

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6113166A (en) * 1984-06-29 1986-01-21 Nec Corp Antenna tracking apparatus
JPS6488270A (en) * 1987-09-30 1989-04-03 Nec Corp Tracking system of moving-body antenna for moving-body satellite communication
JP2001111469A (en) * 1999-10-01 2001-04-20 Communication Research Laboratory Mpt Method for designing satellite orbit arrangement capable of switching satellite in same antenna beam and satellite system using the orbit
JP2001313599A (en) * 2000-04-28 2001-11-09 Hitachi Ltd Communication using non-geostationary satellite, or master side system or slave side unit for broadcast
JP2002124815A (en) * 2000-10-13 2002-04-26 Sony Corp Method and equipment for adjusting direction of multi- beam antenna

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