JP2004364167A

JP2004364167A - Mobile station location detecting system, mobile station, base station and location information center

Info

Publication number: JP2004364167A
Application number: JP2003162610A
Authority: JP
Inventors: Osamu Takemura; 治竹村
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2003-06-06
Filing date: 2003-06-06
Publication date: 2004-12-24

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a mobile station location detecting system in which an inexpensive and small mobile station is used to detect the location of the mobile station. <P>SOLUTION: The mobile station location detecting system is provided with the mobile station 1 for transmitting the mobile station ID of its own station, a plurality of base stations 2 for receiving the mobile station ID, measuring the electric field intensity of a received wave and the directivity of the received wave, and transmitting the measured information together with the received mobile station ID to a public network 3, and a location information center 4 connected to the public network 3 to calculate the location of the mobile station 1 corresponding to the received mobile station ID on the basis of the electric field intensity of the received wave from each base station 2 and the directivity of the received wave. By only the transmission of the mobile station ID of its own station by the mobile station 1, the plurality of base stations 2 measure various information required for calculating the location of the mobile station 1 and transmit the measured information to the location information center 4, and thus the inexpensive and small mobile station 1 is used to detect the location of the mobile station 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、移動局の位置を検出する移動局位置検出システム、移動局、基地局、および位置情報センターに関するものである。
【０００２】
【従来の技術】
従来の移動局位置検出システムにおいては、移動局が複数の基地局からの電波を受信して、移動局において検出された各基地局を識別するＩＤ情報と、複数の基地局からの電波の受信電界強度とをサーバへ送信し、サーバにおいて位置情報を算出する構成にしている（例えば、特許文献１参照）。
【０００３】
【特許文献１】
特開２００２−２４３４６０号公報
【０００４】
【発明が解決しようとする課題】
従来の移動局位置検出システムは以上のように構成されているので、移動局が、複数の基地局からの電波を受信し、移動局自身の位置を算出するための受信電界強度を測定し、受信電界強度をＩＤ情報と共に送信するので、移動局を高機能化する必要があり、移動局が高価で大型化する課題があった。
【０００５】
この発明は上記のような課題を解決するためになされたもので、安価で小型な移動局を用いて移動局の位置を検出する移動局位置検出システムを得ることを目的とする。
この発明は、位置の検出精度を維持し、省電力化を実現する移動局、基地局、および位置情報センターを得ることを目的とする。
【０００６】
【課題を解決するための手段】
この発明に係る移動局位置検出システムは、自局のＩＤ情報を送信する移動局と、そのＩＤ情報を受信し、受信波の電界強度および受信波の指向性を測定し、ＩＤ情報と共に測定情報を送信する複数の基地局と、各基地局からの受信波の電界強度および受信波の指向性に基づいて、ＩＤ情報に応じた移動局の位置を算出する位置情報センターとを備えたものである。
【０００７】
【発明の実施の形態】
以下、この発明の実施の一形態を説明する。
実施の形態１．
図１はこの発明の実施の形態１による移動局位置検出システムを示す構成図であり、図において、移動局１は、自局の移動局ＩＤ（ＩＤ情報）を予め定められた周波数で送信するものである。
複数の基地局２は、移動局１が送信した移動局ＩＤを受信し、受信波の電界強度、受信時刻、受信波の指向性および受信波の予め定められた周波数との周波数偏差を測定し、各自局の基地局ＩＤ、その受信された移動局ＩＤおよびそれら測定情報を公衆網３に送信するものである。
【０００８】
位置情報センター４は、公衆網３に接続され、受信された各基地局ＩＤに応じた各基地局２の位置を調査し、各基地局２からの受信波の電界強度により、各基地局２から移動局１までの距離を算出し、各基地局２の受信時刻により算出される各基地局２から移動局１までの距離に基づいて電界強度により算出された距離を補正し、各基地局２からの受信波の指向性により、各基地局２からの移動局１の方向を算出する。また、各基地局２の位置と、各基地局２から移動局１までの距離と、各基地局２からの移動局１の方向とに基づいて、受信された移動局ＩＤに応じた移動局１の位置を算出し、さらに、各基地局２からの周波数偏差に基づいて、移動局１の移動速度（移動方向および移動の速さ）を算出するものである。
なお、複数の基地局５は、基地局２と同様に公衆網３に接続され、位置情報センター４に測定情報を送信するものであるが、現時点では移動局１に関する測定情報を公衆網３に送信していない。詳しくは、後述する実施の形態３において述べる。
【０００９】
次に動作について説明する。
移動局１は、自局の移動局ＩＤを予め定められた周波数で送信し、その周辺に配置されている各基地局２は、移動局１が送信した移動局ＩＤを受信する。
この時、各基地局２では、その受信波の電界強度、受信時刻、受信波の指向性および受信波の予め定められた周波数との周波数偏差をそれぞれ測定する。また、各基地局２では、各自局の基地局ＩＤ、受信された移動局ＩＤおよびそれら測定情報を公衆網３を通じて位置情報センター４に送信する。
【００１０】
図２はこの発明の実施の形態１による位置情報センターの機能を示すフローチャートであり、図において、位置情報センター４では、まず、受信された各基地局ＩＤに応じた各基地局２の設置位置を調査する（ステップＳＴ１）。これは、位置情報センター４において、例えば、基地局ＩＤに対応する基地局設置位置（経度，緯度）等の情報が記憶されたテーブルを備えておき、そのテーブルから基地局設置位置を抽出することにより実現することができる。
【００１１】
次に、各基地局２からの受信波の電界強度により、各基地局２から移動局１までの距離を算出する（ステップＳＴ２）。
ところで、基地局２と移動局１とを直線で結んだ所に大きなビルディング等の障害物がある場合に、基地局２での受信波は他の物体等からの反射波となり、この場合、電界強度は著しく弱くなり、距離が大きく異なって算出される。しかしながら、電波の伝播時間であれば、他の物体等からの反射波であってもそれほど大きな誤差にはならない。
そこで、位置情報センター４では、移動局１の送信時刻と基地局２の受信時刻との差から、各基地局２から移動局１までの距離を算出する。この時刻差に基づいて算出された各距離と、ステップＳＴ２での電界強度により算出された各距離とを比較し、所定距離以上の誤差がある距離がある場合には、受信時刻により算出された距離に基づいて電界強度により算出された距離を補正する（ステップＳＴ３）。具体的な補正方法としては、例えば、受信時刻により算出された距離の方を採用する等の方法がある。
【００１２】
次に、各基地局２からの受信波の指向性により、各基地局２からの移動局１の方向を算出する（ステップＳＴ４）。
そして、ステップＳＴ１で調査された各基地局２の設置位置、ステップＳＴ２で算出され、ステップＳＴ３で補正された各基地局２から移動局１までの距離、ステップＳＴ４で算出された各基地局２からの移動局１の方向に基づいて、移動局ＩＤに応じた移動局１の位置（経度，緯度）を算出する（ステップＳＴ５）。
さらに、各基地局２が受信する移動局１の周波数には、ドップラー効果によって周波数偏差が生じる。この周波数偏差に基づいて、各基地局２と移動局１との相対速度を算出し（ステップＳＴ６）、算出された相対速度を合成して、移動局１の移動速度（移動方向および移動の速さ）を算出する（ステップＳＴ７）。
【００１３】
以上のように、この実施の形態１によれば、移動局１は、自局の移動局ＩＤを送信するだけで、複数の基地局２が移動局１の位置を算出するための各種情報を測定し、その測定情報を位置情報センター４に送信するので、安価で小型な移動局１を用いて移動局１の位置を検出することができる。
また、受信時刻により算出された各距離と、電界強度により算出された各距離とを比較し、両者に誤差がある場合には、受信時刻により算出された距離に基づいて電界強度により算出された距離を補正するので、各基地局２から移動局１までの距離をより正確に算出することができる。
さらに、複数の基地局２からの受信波の電界強度および受信波の指向性に基づいて移動局１の位置を算出するので、例えば、３台の基地局２から測定情報が得られる場合、測定情報が基準範囲に収まっていれば全て採用し、どれか一つの測定情報が極端に外れている場合にはその測定情報を除外し、残り２つの測定情報を利用する等すれば、位置を正確に算出することができる。すなわち、理論的には、１台の基地局２からの電界強度および指向性に基づいて移動局１の位置を算出することはできるが、この場合は地形あるいは建造物の影響を受けて位置を正確に算出することができない可能性があり、１台の基地局２からだけの測定情報を用いる場合に比べて位置を正確に算出することができる。
さらに、複数の基地局２は、受信波の予め定められた周波数との周波数偏差を測定し、位置情報センター４では、各基地局２からの周波数偏差に基づいて、移動局１の移動速度を算出することができる。
【００１４】
実施の形態２．
この実施の形態２における位置情報センター４は、算出された移動局１の移動速度に応じて移動局１の移動局ＩＤの送信間隔を決定し、基地局２を通じて移動局１にその送信間隔を通知するものである。
また、移動局１は、通知された送信間隔に従い移動局ＩＤを送信するものである。その他の構成については、上記実施の形態１と同等である。
【００１５】
次に動作について説明する。
図３はこの発明の実施の形態２による位置情報センターの機能を示すフローチャートであり、図において、この実施の形態２における位置情報センター４では、移動局１の移動速度に関する２つの閾値Ｖａ，Ｖｂ（Ｖａ＞Ｖｂ）と、移動局１の移動局ＩＤの３つの送信間隔Ｔａ，Ｔｂ，Ｔｃ（Ｔａ＜Ｔｂ＜Ｔｃ）が設定されている。
そして、算出された移動局１の移動速度が閾値Ｖａ以上の場合は（ステップＳＴ１１）、移動局１の移動局ＩＤの送信間隔をＴａに決定し（ステップＳＴ１２）、算出された移動局１の移動速度が閾値Ｖｂより大きく、閾値Ｖａより小さい場合は（ステップＳＴ１３）、移動局１の移動局ＩＤの送信間隔をＴｂに決定し（ステップＳＴ１４）、算出された移動局１の移動速度が閾値Ｖｂ以下の場合は（ステップＳＴ１３）、移動局１の移動局ＩＤの送信間隔をＴｃに決定する（ステップＳＴ１５）。
このように、位置情報センター４では、算出された移動局１の移動速度が速ければ移動局１の移動局ＩＤの送信間隔を短く、逆に移動局１の移動速度が遅ければ送信間隔を長く決定し、基地局２を通じて移動局１に送信間隔を通知し、移動局１では、その通知された送信間隔に従い移動局ＩＤを送信する。
【００１６】
以上のように、この実施の形態２によれば、位置情報センター４は、算出した移動局１の移動速度に応じて移動局１の移動局ＩＤの送信間隔を決定し、基地局２を通じて移動局１にその送信間隔を通知し、移動局１は、通知された送信間隔に従い移動局ＩＤを送信するので、移動局１の移動速度が速ければ送信間隔を短く設定することで、位置測定精度を維持することができ、逆に移動局１の移動速度が遅ければ送信間隔を長く設定することで、無線回線のトラヒックの抑制と移動局１の省電力化を実現することができる。
【００１７】
実施の形態３．
この実施の形態３における位置情報センター４は、移動局１の移動局ＩＤの送信間隔、移動局１の測定位置および移動速度に基づいて、次回の移動局ＩＤ送信時の移動局１の位置を随時予測し、次回の予測位置と次回の移動局ＩＤ送信時に測定される測定位置とを比較する。
予測位置と測定位置との誤差が予め定められた範囲内であることが所定回数連続した時に、複数の基地局２のうちの一つまたは複数の基地局２に対し、基地局ＩＤ、移動局ＩＤ、および測定情報の位置情報センター４への送信の停止を指示する。
予測位置と測定位置との誤差が予め定められた範囲外であることが所定回数連続した時に、複数の基地局２の他の一つまたは複数の基地局５に対し（図１参照）、基地局ＩＤ、移動局ＩＤ、および測定情報の位置情報センター４への送信を指示するものである。その他の構成については、上記実施の形態２と同等である。
【００１８】
次に動作について説明する。
図４はこの発明の実施の形態３による位置情報センターの機能を示すフローチャートであり、図において、位置情報センター４では、例えば、上記実施の形態２で決定される移動局１による移動局ＩＤの送信間隔と、上記実施の形態１で算出される移動局ＩＤの前回送信時の移動局１の測定位置と、上記実施の形態１で算出される移動局１の移動速度とに基づいて、移動局ＩＤの次回送信時の移動局１の位置を随時予測する。そして、その移動局ＩＤの次回送信時の移動局１の予測位置を随時Ｐａと置く（ステップＳＴ２１）。
その後、次回の予測位置Ｐａと移動局ＩＤの次回送信時に測定される移動局１の測定位置とを比較する（ステップＳＴ２２）。この比較は、移動局ＩＤの送信毎に行う。
【００１９】
予測位置Ｐａと測定位置との誤差が予め定められた範囲内であることが所定回数ｎ（ｎは任意に設定可能な自然数）連続した時に（ステップＳＴ２３）、複数の基地局２のうちの一つまたは複数の基地局２に対し、基地局ＩＤ、移動局ＩＤ、および測定情報の位置情報センター４への送信の停止を指示する（ステップＳＴ２４）。すなわち、図１において、移動局１の位置測定に３台の基地局２が用いられていた場合に、移動局１の位置測定に用いられる基地局２の台数を２台か１台に減少させる。
【００２０】
また、予測位置Ｐａと測定位置との誤差が予め定められた範囲外であることが所定回数ｍ（ｍは任意に設定可能な自然数）連続した時に（ステップＳＴ２５）、複数の基地局５のうちの一つまたは複数の基地局５に対し、基地局ＩＤ、移動局ＩＤ、および測定情報の位置情報センター４への送信を指示する（ステップＳＴ２６）。すなわち、図１において、移動局１の位置測定に３台の基地局２が用いられていた場合に、移動局１の位置測定に用いられる基地局の台数を、３台の基地局２の他、基地局５の台数を２台か１台増加させる。そして、位置情報センター４では、複数の基地局２，５からの測定情報のうちの誤差の大きい測定情報を除外して、位置測定を行う。
【００２１】
以上のように、この実施の形態３によれば、移動局１の予測位置と測定位置との誤差が小さい場合に、移動局１の位置測定が精度良く行われていると判断し、基地局ＩＤ、移動局ＩＤ、および測定情報を送信する基地局２の数を減少させ、無用な基地局２の負荷を抑制することができる。
また、移動局１の予測位置と測定位置との誤差が大きい場合に、移動局１の位置測定の精度が低下していると判断し、基地局ＩＤ、移動局ＩＤ、および測定情報を送信する基地局２，５の数を追加し、移動局１の位置測定の精度を向上させることができる。
【００２２】
実施の形態４．
この実施の形態４における位置情報センター４は、移動局１の移動局ＩＤの送信間隔、移動局１の測定位置および移動速度に基づいて、次回の移動局ＩＤ送信時の移動局１の位置を随時予測し、次回の予測位置が予め定められた領域内である場合に、その領域に応じて予め設定された移動局１の移動局ＩＤの送信間隔に決定し、基地局２を通じて移動局１にその送信間隔を通知するものである。
また、移動局１は、その通知された送信間隔に従い移動局ＩＤを送信するものである。その他の構成については、上記実施の形態２と同等である。
【００２３】
次に動作について説明する。
図５はこの発明の実施の形態４による位置情報センターの機能を示すフローチャートであり、図において、位置情報センター４では、上記実施の形態３と同様に、移動局ＩＤの送信間隔と、移動局ＩＤの前回送信時の移動局１の測定位置と、移動局１の移動速度とに基づいて、移動局ＩＤの次回送信時の移動局１の位置を随時予測し、その移動局ＩＤの次回送信時の移動局１の予測位置を随時Ｐａと置く（ステップＳＴ３１）。
そして、次回の予測位置Ｐａが予め定められた領域Ｘ内であるか判定する（ステップＳＴ３２）。ここで、領域Ｘとは、例えば、ビルディングが林立するような電波状況の悪い領域である。
次回の予測位置Ｐａが領域Ｘ内であると判定された場合に、その領域Ｘに応じて予め設定された移動局１の移動局ＩＤの送信間隔Ｔｘに決定し（ステップＳＴ３３）、基地局２を通じて移動局１にその送信間隔Ｔｘを通知し、移動局１は、通知された送信間隔Ｔｘに従い移動局ＩＤを送信する。
また、次回の予測位置Ｐａが領域Ｘ内でないと判定された場合には、今までと同様な送信間隔Ｔｙに決定する（ステップＳＴ３４）。なお、送信間隔Ｔｙは、送信間隔Ｔｘよりも長い。
【００２４】
以上のように、この実施の形態４によれば、位置情報センター４は、次回の予測位置Ｐａが予め定められた領域Ｘ内である場合に、その領域Ｘに応じて予め設定された移動局１の移動局ＩＤの送信間隔Ｔｘに決定し、基地局２を通じて移動局１に送信間隔Ｔｘを通知し、移動局１は、その通知された送信間隔Ｔｘに従い移動局ＩＤを送信するので、例えば、予め定められた領域Ｘがビルディングが林立するような電波状況の悪い地域では送信間隔Ｔｘを短く設定しておくことによって、そのような電波状況の悪い地域Ｘ内に入ることが予想される場合に移動局１の移動局ＩＤの送信間隔を短くすることができ、位置測定精度を維持することができる。
【００２５】
実施の形態５．
この実施の形態５における位置情報センター４は、移動局１の移動局ＩＤの送信間隔、移動局１の測定位置および移動速度に基づいて、次回の移動局ＩＤ送信時の移動局１の位置を随時予測し、次回の予測位置が予め定められた領域内である場合に、その領域に応じて予め設定された複数の基地局２に対し、基地局ＩＤ、移動局ＩＤ、および測定情報の位置情報センター４への送信を指示するものである。その他の構成については、上記実施の形態２と同等である。
【００２６】
次に動作について説明する。
図６はこの発明の実施の形態５による位置情報センターの機能を示すフローチャートであり、図において、位置情報センター４では、上記実施の形態３と同様に、移動局ＩＤの送信間隔と、移動局ＩＤの前回送信時の移動局１の測定位置と、移動局１の移動速度とに基づいて、移動局ＩＤの次回送信時の移動局１の位置を随時予測し、その移動局ＩＤの次回送信時の移動局１の予測位置をＰａと置く（ステップＳＴ４１）。
そして、次回の予測位置Ｐａが予め定められた領域Ｚ内であるか判定する（ステップＳＴ４２）。ここで、この領域Ｚとは、例えば、見晴らしが良く電波状況の良い領域である。
次回の予測位置Ｐａが領域Ｚ内であると判定された場合に、その領域Ｚに応じて予め設定された複数の基地局２の組合せＵｚ０が移動局１の位置測定に用いられるように、その組合せＵｚ０に対応した複数の基地局２に対し、基地局ＩＤ、移動局ＩＤ、および測定情報の位置情報センター４への送信を指示する（ステップＳＴ４３）。
また、次回の予測位置Ｐａが領域Ｚ内でないと判定された場合には、今までと同様な複数の基地局２の組合せＵｚ１に決定する（ステップＳＴ４４）。なお、組合せＵｚ０に含まれる基地局２の数は、組合せＵｚ１に含まれる基地局２の数よりも少ない。
【００２７】
以上のように、この実施の形態５によれば、位置情報センター４は、次回の予測位置Ｐａが予め定められた領域Ｚ内である場合に、その領域Ｚに応じて予め設定された複数の基地局２に対し、基地局ＩＤ、移動局ＩＤ、および測定情報の位置情報センター４への送信を指示するので、例えば、予め定められた領域Ｚが見晴らしが良く電波状況の良い地域では基地局２の数を少なく設定しておくことによって、そのような電波状況の良い地域Ｚ内に入ることが予想される場合に、基地局２の数を少なくすることができ、無用な基地局２の負荷を抑制することができる。
【００２８】
【発明の効果】
以上のように、この発明によれば、移動局は、自局のＩＤ情報を送信するだけで、複数の基地局がその移動局の位置を算出するための各種情報を測定し、その測定情報を位置情報センターに送信するので、安価で小型な移動局を用いて移動局の位置を検出することができる効果がある。
【図面の簡単な説明】
【図１】この発明の実施の形態１による移動局位置検出システムを示す構成図である。
【図２】この発明の実施の形態１による位置情報センターの機能を示すフローチャートである。
【図３】この発明の実施の形態２による位置情報センターの機能を示すフローチャートである。
【図４】この発明の実施の形態３による位置情報センターの機能を示すフローチャートである。
【図５】この発明の実施の形態４による位置情報センターの機能を示すフローチャートである。
【図６】この発明の実施の形態５による位置情報センターの機能を示すフローチャートである。
【符号の説明】
１移動局、２，５基地局、３公衆網、４位置情報センター。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mobile station position detecting system for detecting a position of a mobile station, a mobile station, a base station, and a position information center.
[0002]
[Prior art]
In a conventional mobile station position detection system, a mobile station receives radio waves from a plurality of base stations, ID information for identifying each base station detected by the mobile station, and reception of radio waves from a plurality of base stations. The electric field strength is transmitted to the server, and the server calculates the position information (for example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-243460
[Problems to be solved by the invention]
Since the conventional mobile station position detection system is configured as described above, the mobile station receives radio waves from a plurality of base stations, measures the received electric field strength for calculating the position of the mobile station itself, Since the received electric field strength is transmitted together with the ID information, it is necessary to enhance the function of the mobile station, and there is a problem that the mobile station is expensive and large.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a mobile station position detection system that detects the position of a mobile station using an inexpensive and small mobile station.
An object of the present invention is to obtain a mobile station, a base station, and a location information center that maintain the position detection accuracy and realize power saving.
[0006]
[Means for Solving the Problems]
A mobile station position detection system according to the present invention transmits a mobile station transmitting its own ID information, receives the ID information, measures the electric field strength of the received wave and the directivity of the received wave, and measures the measurement information together with the ID information. And a position information center that calculates the position of the mobile station according to the ID information based on the electric field strength and the directivity of the received wave from each base station. is there.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing a mobile station position detecting system according to Embodiment 1 of the present invention. In the figure, a mobile station 1 transmits its own mobile station ID (ID information) at a predetermined frequency. Things.
The plurality of base stations 2 receive the mobile station ID transmitted by the mobile station 1, and measure the electric field strength of the received wave, the reception time, the directivity of the received wave, and the frequency deviation of the received wave from a predetermined frequency. The base station ID of each station, the received mobile station ID, and the measurement information are transmitted to the public network 3.
[0008]
The location information center 4 is connected to the public network 3 and investigates the position of each base station 2 corresponding to each received base station ID, and determines the position of each base station 2 based on the electric field strength of the wave received from each base station 2. From the base station 2 to the mobile station 1, and corrects the distance calculated based on the electric field strength based on the distance from each base station 2 to the mobile station 1 calculated based on the reception time of each base station 2. The direction of the mobile station 1 from each base station 2 is calculated based on the directivity of the reception wave from the base station 2. Also, based on the position of each base station 2, the distance from each base station 2 to the mobile station 1, and the direction of the mobile station 1 from each base station 2, the mobile station corresponding to the received mobile station ID 1 and calculates the moving speed (moving direction and moving speed) of the mobile station 1 based on the frequency deviation from each base station 2.
The plurality of base stations 5 are connected to the public network 3 like the base station 2 and transmit measurement information to the location information center 4. At this time, measurement information about the mobile station 1 is transmitted to the public network 3. Not sent. Details will be described in a third embodiment described later.
[0009]
Next, the operation will be described.
The mobile station 1 transmits its own mobile station ID at a predetermined frequency, and each of the base stations 2 disposed around the mobile station 1 receives the mobile station ID transmitted by the mobile station 1.
At this time, each base station 2 measures the electric field strength of the received wave, the reception time, the directivity of the received wave, and the frequency deviation of the received wave from a predetermined frequency. Further, each base station 2 transmits its own base station ID, the received mobile station ID and their measurement information to the location information center 4 via the public network 3.
[0010]
FIG. 2 is a flowchart showing the function of the location information center according to Embodiment 1 of the present invention. In the figure, the location information center 4 first installs each base station 2 according to each received base station ID. Is checked (step ST1). This is because, for example, the location information center 4 is provided with a table in which information such as a base station installation position (longitude and latitude) corresponding to the base station ID is stored, and the base station installation position is extracted from the table. Can be realized.
[0011]
Next, the distance from each base station 2 to the mobile station 1 is calculated based on the electric field strength of the received wave from each base station 2 (step ST2).
By the way, when there is an obstacle such as a large building at a place where the base station 2 and the mobile station 1 are connected by a straight line, the received wave at the base station 2 is a reflected wave from another object or the like. The intensity is significantly reduced, and the distance is calculated to be significantly different. However, as long as the propagation time of a radio wave, even a reflected wave from another object or the like does not cause a great error.
Thus, the location information center 4 calculates the distance from each base station 2 to the mobile station 1 from the difference between the transmission time of the mobile station 1 and the reception time of the base station 2. Each distance calculated based on the time difference is compared with each distance calculated based on the electric field strength in step ST2, and if there is a distance having an error equal to or more than a predetermined distance, the distance is calculated based on the reception time. The distance calculated based on the electric field strength is corrected based on the distance (step ST3). As a specific correction method, for example, there is a method of adopting the distance calculated based on the reception time.
[0012]
Next, the direction of the mobile station 1 from each base station 2 is calculated based on the directivity of the received wave from each base station 2 (step ST4).
Then, the installation position of each base station 2 investigated in step ST1, the distance from each base station 2 to mobile station 1 calculated in step ST2 and corrected in step ST3, and each base station 2 calculated in step ST4 Based on the direction of the mobile station 1 from, the position (longitude, latitude) of the mobile station 1 corresponding to the mobile station ID is calculated (step ST5).
Further, the frequency of the mobile station 1 received by each base station 2 has a frequency deviation due to the Doppler effect. Based on the frequency deviation, the relative speed between each base station 2 and the mobile station 1 is calculated (step ST6), and the calculated relative speeds are combined to obtain the moving speed (moving direction and moving speed) of the mobile station 1. Is calculated (step ST7).
[0013]
As described above, according to the first embodiment, mobile station 1 only transmits its own mobile station ID, and a plurality of base stations 2 transmit various types of information for calculating the position of mobile station 1. Since the measurement is performed and the measurement information is transmitted to the location information center 4, the position of the mobile station 1 can be detected using the inexpensive and small mobile station 1.
Further, each distance calculated based on the reception time is compared with each distance calculated based on the electric field strength, and when there is an error between the two, the distance is calculated based on the electric field strength based on the distance calculated based on the reception time. Since the distance is corrected, the distance from each base station 2 to the mobile station 1 can be calculated more accurately.
Further, since the position of the mobile station 1 is calculated based on the electric field strengths of the received waves from the plurality of base stations 2 and the directivity of the received waves, for example, if measurement information is obtained from three base stations 2, If the information falls within the reference range, all are adopted. If any one of the measurement information is extremely out of range, the measurement information is excluded, and if the remaining two measurement information are used, the position can be accurately determined. Can be calculated. That is, theoretically, the position of the mobile station 1 can be calculated based on the electric field intensity and directivity from one base station 2, but in this case, the position is affected by the topography or the building. It may not be possible to calculate accurately, and the position can be calculated more accurately than when using measurement information from only one base station 2.
Further, the plurality of base stations 2 measure the frequency deviation of the received wave from a predetermined frequency, and the position information center 4 determines the moving speed of the mobile station 1 based on the frequency deviation from each base station 2. Can be calculated.
[0014]
Embodiment 2 FIG.
The position information center 4 according to the second embodiment determines the transmission interval of the mobile station ID of the mobile station 1 according to the calculated moving speed of the mobile station 1, and sends the transmission interval to the mobile station 1 through the base station 2. Notify.
The mobile station 1 transmits a mobile station ID according to the notified transmission interval. Other configurations are the same as those in the first embodiment.
[0015]
Next, the operation will be described.
FIG. 3 is a flowchart showing the function of the location information center according to the second embodiment of the present invention. In the figure, the location information center 4 according to the second embodiment has two thresholds Va and Vb relating to the moving speed of the mobile station 1. (Va> Vb) and three transmission intervals Ta, Tb, Tc of the mobile station ID of the mobile station 1 (Ta <Tb <Tc) are set.
If the calculated moving speed of the mobile station 1 is equal to or higher than the threshold value Va (step ST11), the transmission interval of the mobile station ID of the mobile station 1 is determined to be Ta (step ST12), and the calculated mobile station 1 If the moving speed is larger than the threshold value Vb and smaller than the threshold value Va (step ST13), the transmission interval of the mobile station ID of the mobile station 1 is determined to be Tb (step ST14), and the calculated moving speed of the mobile station 1 is set to the threshold value. If not more than Vb (step ST13), the transmission interval of the mobile station ID of the mobile station 1 is determined to be Tc (step ST15).
As described above, in the location information center 4, if the calculated moving speed of the mobile station 1 is high, the transmission interval of the mobile station ID of the mobile station 1 is short, and if the moving speed of the mobile station 1 is low, the transmission interval is long. The transmission interval is notified to the mobile station 1 through the base station 2 and the mobile station 1 transmits the mobile station ID according to the notified transmission interval.
[0016]
As described above, according to the second embodiment, the location information center 4 determines the transmission interval of the mobile station ID of the mobile station 1 according to the calculated moving speed of the mobile station 1, and moves through the base station 2. Since the transmission interval is notified to the station 1, and the mobile station 1 transmits the mobile station ID in accordance with the notified transmission interval, if the moving speed of the mobile station 1 is high, the transmission interval is set to be short, so that the position measurement accuracy can be improved. In contrast, if the moving speed of the mobile station 1 is low, by setting the transmission interval to be long, it is possible to suppress the traffic on the radio line and save the power of the mobile station 1.
[0017]
Embodiment 3 FIG.
The position information center 4 according to the third embodiment determines the position of the mobile station 1 at the next transmission of the mobile station ID based on the transmission interval of the mobile station ID of the mobile station 1, the measured position of the mobile station 1, and the moving speed. Prediction is made at any time, and the next predicted position is compared with the measured position measured at the next transmission of the mobile station ID.
When the error between the predicted position and the measured position is within a predetermined range for a predetermined number of times, the base station ID and the mobile station are assigned to one or more base stations 2 of the plurality of base stations 2. The transmission of the ID and the measurement information to the position information center 4 is instructed.
When the error between the predicted position and the measured position is out of the predetermined range for a predetermined number of times, the base station 2 transmits a signal to another one or a plurality of base stations 5 (see FIG. 1). It instructs transmission of the station ID, the mobile station ID, and the measurement information to the location information center 4. Other configurations are the same as those of the second embodiment.
[0018]
Next, the operation will be described.
FIG. 4 is a flowchart showing a function of the location information center according to the third embodiment of the present invention. In the figure, the location information center 4 is, for example, a mobile station ID determined by the mobile station 1 determined in the second embodiment. The mobile station moves based on the transmission interval, the measured position of the mobile station 1 at the time of the previous transmission of the mobile station ID calculated in the first embodiment, and the moving speed of the mobile station 1 calculated in the first embodiment. The position of the mobile station 1 at the next transmission of the station ID is predicted at any time. Then, the predicted position of the mobile station 1 at the time of the next transmission of the mobile station ID is set to Pa as needed (step ST21).
Thereafter, the next predicted position Pa is compared with the measured position of the mobile station 1 measured at the next transmission of the mobile station ID (step ST22). This comparison is performed every time the mobile station ID is transmitted.
[0019]
When the error between the predicted position Pa and the measured position is within a predetermined range for a predetermined number of times n (n is a natural number that can be set arbitrarily) (step ST23), one of the base stations 2 One or more base stations 2 are instructed to stop transmitting the base station ID, the mobile station ID, and the measurement information to the location information center 4 (step ST24). That is, in FIG. 1, when three base stations 2 are used for position measurement of the mobile station 1, the number of base stations 2 used for position measurement of the mobile station 1 is reduced to two or one. .
[0020]
Further, when the error between the predicted position Pa and the measured position is out of the predetermined range for a predetermined number of times m (m is a natural number that can be arbitrarily set) (step ST25), among the plurality of base stations 5, To one or more base stations 5 to transmit the base station ID, the mobile station ID, and the measurement information to the location information center 4 (step ST26). That is, in FIG. 1, when three base stations 2 are used for position measurement of the mobile station 1, the number of base stations used for position measurement of the mobile station 1 is changed to three base stations 2. , The number of base stations 5 is increased by two or one. Then, the position information center 4 performs position measurement while excluding measurement information having a large error from the measurement information from the plurality of base stations 2 and 5.
[0021]
As described above, according to the third embodiment, when the error between the predicted position and the measured position of mobile station 1 is small, it is determined that position measurement of mobile station 1 is performed with high accuracy, and base station The number of base stations 2 that transmit IDs, mobile station IDs, and measurement information can be reduced, and unnecessary loads on the base station 2 can be suppressed.
When the error between the predicted position and the measured position of the mobile station 1 is large, it is determined that the accuracy of the position measurement of the mobile station 1 has decreased, and the base station ID, the mobile station ID, and the measurement information are transmitted. By adding the number of base stations 2 and 5, the accuracy of position measurement of the mobile station 1 can be improved.
[0022]
Embodiment 4 FIG.
The position information center 4 in the fourth embodiment determines the position of the mobile station 1 at the next transmission of the mobile station ID based on the transmission interval of the mobile station ID of the mobile station 1, the measured position of the mobile station 1, and the moving speed. Prediction is performed at any time, and when the next predicted position is within a predetermined area, the transmission interval of the mobile station ID of the mobile station 1 set in advance according to the area is determined. Is notified of the transmission interval.
The mobile station 1 transmits a mobile station ID according to the notified transmission interval. Other configurations are the same as those of the second embodiment.
[0023]
Next, the operation will be described.
FIG. 5 is a flowchart showing the function of the location information center according to the fourth embodiment of the present invention. In the figure, in the location information center 4, the transmission interval of the mobile station ID, The position of the mobile station 1 at the next transmission of the mobile station ID is predicted at any time based on the measured position of the mobile station 1 at the previous transmission of the ID and the moving speed of the mobile station 1, and the next transmission of the mobile station ID is performed. The predicted position of the mobile station 1 at that time is set to Pa at any time (step ST31).
Then, it is determined whether the next predicted position Pa is within the predetermined area X (step ST32). Here, the area X is an area having a poor radio wave condition, for example, a building stands.
When it is determined that the next predicted position Pa is within the area X, the transmission interval Tx of the mobile station ID of the mobile station 1 set in advance according to the area X is determined (step ST33), and the base station 2 The transmission interval Tx is notified to the mobile station 1 through the mobile station 1, and the mobile station 1 transmits the mobile station ID according to the notified transmission interval Tx.
If it is determined that the next predicted position Pa is not within the area X, the transmission interval Ty is determined to be the same as before (step ST34). Note that the transmission interval Ty is longer than the transmission interval Tx.
[0024]
As described above, according to the fourth embodiment, when the next predicted position Pa is within the predetermined area X, the position information center 4 sets the mobile station preset according to the area X. 1 is determined as the transmission interval Tx of the mobile station ID of 1, and the transmission interval Tx is notified to the mobile station 1 through the base station 2. The mobile station 1 transmits the mobile station ID according to the notified transmission interval Tx. In a case where a predetermined region X is in an area where the radio wave condition is poor such that a building stands, it is expected that the transmission interval Tx is set to be short to enter the area X where the radio wave condition is poor. Therefore, the transmission interval of the mobile station ID of the mobile station 1 can be shortened, and the position measurement accuracy can be maintained.
[0025]
Embodiment 5 FIG.
The position information center 4 in the fifth embodiment determines the position of the mobile station 1 at the next transmission of the mobile station ID based on the transmission interval of the mobile station ID of the mobile station 1, the measured position of the mobile station 1, and the moving speed. Predict at any time, and when the next predicted position is within a predetermined area, the base station ID, the mobile station ID, and the position of the measurement information for a plurality of base stations 2 set in advance according to the area. This is to instruct transmission to the information center 4. Other configurations are the same as those of the second embodiment.
[0026]
Next, the operation will be described.
FIG. 6 is a flowchart showing the function of the location information center according to the fifth embodiment of the present invention. In the figure, in the location information center 4, the transmission interval of the mobile station ID, The position of the mobile station 1 at the next transmission of the mobile station ID is predicted at any time based on the measured position of the mobile station 1 at the previous transmission of the ID and the moving speed of the mobile station 1, and the next transmission of the mobile station ID is performed. The predicted position of the mobile station 1 at the time is set as Pa (step ST41).
Then, it is determined whether the next predicted position Pa is within the predetermined area Z (step ST42). Here, the area Z is, for example, an area with a good view and a good radio wave condition.
When it is determined that the next predicted position Pa is within the area Z, the combination Uz0 of the plurality of base stations 2 set in advance according to the area Z is used so as to be used for position measurement of the mobile station 1. It instructs a plurality of base stations 2 corresponding to the combination Uz0 to transmit the base station ID, the mobile station ID, and the measurement information to the location information center 4 (step ST43).
If it is determined that the next predicted position Pa is not within the area Z, the combination Uz1 of the plurality of base stations 2 is determined as in the past (step ST44). Note that the number of base stations 2 included in combination Uz0 is smaller than the number of base stations 2 included in combination Uz1.
[0027]
As described above, according to the fifth embodiment, when the next predicted position Pa is within the predetermined region Z, the position information center 4 sets a plurality of positions set in advance according to the region Z. Since the base station 2 is instructed to transmit the base station ID, the mobile station ID, and the measurement information to the location information center 4, for example, in a region where the predetermined area Z has a good view and the radio wave condition is good, the base station 2 is used. By setting the number of base stations 2 small, it is possible to reduce the number of base stations 2 when it is expected to enter the area Z with such good radio wave conditions, The load can be suppressed.
[0028]
【The invention's effect】
As described above, according to the present invention, a mobile station simply transmits its own ID information, and a plurality of base stations measure various types of information for calculating the position of the mobile station. Is transmitted to the location information center, so that the position of the mobile station can be detected using an inexpensive and small mobile station.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a mobile station position detection system according to Embodiment 1 of the present invention.
FIG. 2 is a flowchart showing functions of a location information center according to the first embodiment of the present invention.
FIG. 3 is a flowchart showing functions of a location information center according to Embodiment 2 of the present invention.
FIG. 4 is a flowchart showing functions of a location information center according to Embodiment 3 of the present invention.
FIG. 5 is a flowchart showing functions of a location information center according to Embodiment 4 of the present invention.
FIG. 6 is a flowchart showing functions of a location information center according to Embodiment 5 of the present invention.
[Explanation of symbols]
1 mobile station, 2,5 base stations, 3 public network, 4 location information center.

Claims

A mobile station transmitting its own ID information;
A plurality of base stations for receiving the ID information, measuring the electric field strength of the received wave and the directivity of the received wave, and transmitting the measurement information together with the received ID information to a public network;
A position information center that is connected to the public network and that calculates the position of the mobile station according to the received ID information based on the electric field strength of the reception wave from each of the base stations and the directivity of the reception wave. Mobile station position detection system equipped.

A mobile station transmitting its own ID information at a predetermined frequency;
The ID information is received, the electric field strength of the received wave, the directivity of the received wave, and the frequency deviation of the received wave from a predetermined frequency are measured, and the measurement information is transmitted to the public network together with the received ID information. Multiple base stations,
The mobile station is connected to the public network and calculates the position of the mobile station according to the received ID information based on the electric field strength of the reception wave from each of the base stations and the directivity of the reception wave, and And a position information center that calculates a moving speed of the mobile station based on a frequency deviation from the mobile station.

The location information center
A transmission interval of the ID information of the mobile station is determined according to the calculated moving speed of the mobile station, and the transmission interval is notified to the mobile station through the base station.
3. The mobile station position detecting system according to claim 2, wherein the mobile station transmits ID information according to the notified transmission interval.

The location information center
Based on the transmission interval of the ID information of the mobile station, the measured position of the mobile station, and the moving speed, the position of the mobile station at the time of transmitting the next ID information is predicted at any time,
The next predicted position is compared with the measured position measured at the next transmission of the ID information, and when the error between the predicted position and the measured position is within a predetermined range for a predetermined number of times,
The mobile station position detecting system according to claim 2, wherein one or more of the plurality of base stations are instructed to stop transmitting ID information and measurement information to the position information center. .

The location information center
Based on the transmission interval of the ID information of the mobile station, the measured position of the mobile station, and the moving speed, the position of the mobile station at the time of transmitting the next ID information is predicted at any time,
The next predicted position is compared with the measured position measured at the next transmission of the ID information, and when the error between the predicted position and the measured position is out of a predetermined range for a predetermined number of times,
3. The mobile station position detection system according to claim 2, wherein one or more other base stations of the plurality of base stations are instructed to transmit ID information and measurement information to the position information center.

The location information center
Based on the transmission interval of the ID information of the mobile station, the measured position of the mobile station, and the moving speed, the position of the mobile station at the time of transmitting the next ID information is predicted at any time,
If the next predicted position is within a predetermined region, the transmission interval of the mobile station ID information set in advance according to the region is determined, and the transmission interval is notified to the mobile station through the base station. And
3. The mobile station position detecting system according to claim 2, wherein the mobile station transmits ID information according to the notified transmission interval.

The location information center
Based on the transmission interval of the ID information of the mobile station, the measured position of the mobile station, and the moving speed, the position of the mobile station at the time of transmitting the next ID information is predicted at any time,
When the next predicted position is within a predetermined region, instructing a plurality of base stations preset according to the region to transmit ID information and measurement information to the position information center. The mobile station position detecting system according to claim 2, wherein:

A mobile station that transmits its own ID information at a predetermined frequency as needed and, when receiving a notification from the base station that changes the transmission interval of the ID information, transmits the ID information according to the transmitted transmission interval.

The ID information from the mobile station is received, the electric field strength of the received wave, the directivity of the received wave, and the frequency deviation of the received wave from a predetermined frequency are measured, and the measurement information is transmitted to the public together with the received ID information. A transmission is made to the location information center through the network, and when a notification of the transmission interval of the ID information is received from the location information center through the public network, the transmission interval of the ID information is notified to the mobile station corresponding to the ID information. base station.

When receiving the electric field strength of the received wave, the directivity of the received wave, and the frequency deviation of the received wave from a predetermined frequency together with the ID information about the mobile station from the plurality of base stations through the public network, the reception from each base station is performed. Based on the electric field strength of the wave and the directivity of the received wave, the position of the mobile station is calculated according to the received ID information, and the moving speed of the mobile station is calculated based on the frequency deviation from each base station. Calculating a transmission interval of the ID information of the mobile station according to the calculated position and moving speed of the mobile station, and transmitting the ID information to the mobile station through one of the plurality of base stations. Location information center that notifies the interval.