JP2009075032A - Location detection system - Google Patents
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Abstract
Description
本発明は，移動体に搭載されたアンテナによって，一定方向に等間隔で設置された無線タグ等の電波信号発信手段から発信される位置情報の信号を受信し，電波信号発信手段と移動体との相対位置を検出するための位置検出システムに関するものである。 The present invention receives a position information signal transmitted from radio wave signal transmitting means such as a radio tag installed at equal intervals in a fixed direction by an antenna mounted on a mobile body, and the radio signal transmitting means, the mobile body, The present invention relates to a position detection system for detecting the relative position of the.
無線タグ等のようにその識別情報を無線送信する複数の電波信号発信手段が一定方向に等間隔で並べられていることによって，この電波信号発信手段からの信号電波をアンテナによって受信して移動体の現在位置を検出する位置検出システムが知られている。この場合，上記通信手段は，複数の電波信号発信手段のうち，移動体に設けられたアンテナに接近している取り付け位置が既知である電波信号発信手段から発信された電波信号を受信する。アンテナに接続された位置検出手段は，該電波信号により伝送された識別情報からアンテナに最接近している電波信号発信手段を特定し，アンテナの位置，即ち移動体の現在位置を検出する（例えば，特許文献１）。
このような位置検出システムによれば，アンテナから各電波信号発信手段に向けて送信する電波信号の出力を増大させることによって，各電波信号発信手段から移動体が離れた場合にも該移動体の位置検出が可能となり，また，上記取り付け位置が既知である電波信号発信手段を適切な位置に多数設けることによって，移動体がどこにいても自己の位置を知ることが出来る位置検出システムを提供することが出来る。 According to such a position detection system, by increasing the output of the radio signal transmitted from the antenna to each radio signal transmission means, even when the mobile body is separated from each radio signal transmission means, To provide a position detection system that can detect a position and can know its own position wherever a moving body is provided by providing a large number of radio wave signal transmitting means whose mounting positions are known at appropriate positions. I can do it.
しかしながら，上記のような取り付け位置が既知である電波信号発信手段を設けてそれを基準に移動体の位置を検出する上記従来のシステムでは，基準となる取り付け位置が既知である電波信号発信手段を多数設けなければならないので費用が掛り，事実上，それほど大きい領域をカバーする位置検出システムを提供することが出来ない。 However, in the above-described conventional system in which the radio wave signal transmitting means having the known mounting position as described above is provided and the position of the moving body is detected based on the radio wave signal transmitting means, the radio signal transmitting means having the known mounting position as the reference is provided. Since it is necessary to provide a large number, it is expensive, and it is practically impossible to provide a position detection system that covers a very large area.
ところで，各電波信号発信手段が受ける電波信号の強度は，各移動体に設けられたアンテナからの送信電力に依存し，また，概ね，通信手段のアンテナから各電波信号発信手段までの距離の２乗に反比例する。 By the way, the strength of the radio signal received by each radio signal transmission means depends on the transmission power from the antenna provided in each mobile body, and is roughly 2 of the distance from the antenna of the communication means to each radio signal transmission means. Inversely proportional to the power.
即ち，図１のグラフに模式的に示すように，３個のアンテナの送信電力をＡ，Ｂ，Ｃとしたときに距離の２乗に反比例して到達電力が変化するので，最小動作電力になる距離が最大検出距離であり，送信電力に対応してｒａ，ｒｂ，ｒｃとなる。
実際の電波信号発信手段の位置測定は，この最大検出距離とその時の最小作動電力との関係を利用して行い，最小動作電力を測定することで，その時のアンテナと電波信号発信手段との距離を検出する。
しかし，各電波信号発信手段が具備するＩＣチップ特性のバラツキや，各電波信号発信手段の構造（アンテナ形状やアンテナとチップの接合状態等）のバラツキ等により各電波信号発信手段の感度が異なるために，最小動作電力がより大きいもの（感度Ｘ）とより小さいもの（感度Ｙ）とがあるとすると，それぞれの最大検出距離は，同じ送信電力ＡであってもｒａＸ，ｒａＹと異なってしまい，移動体側のアンテナが同じ電力で送信していても，電波信号発信手段により最大検出距離が異なるので，アンテナと電波信号発信手段との相対位置を確認することが困難である。
That is, as schematically shown in the graph of FIG. 1, when the transmission power of the three antennas is A, B, and C, the reached power changes in inverse proportion to the square of the distance, so the minimum operating power is reduced. Is the maximum detection distance, and becomes ra, rb, rc corresponding to the transmission power.
The actual position measurement of the radio signal transmitting means is performed using the relationship between the maximum detection distance and the minimum operating power at that time, and the minimum operating power is measured to determine the distance between the antenna and the radio signal transmitting means at that time. Is detected.
However, the sensitivity of each radio signal transmission means varies depending on the variation of the IC chip characteristics of each radio signal transmission means and the variation of the structure of each radio signal transmission means (antenna shape, antenna and chip connection state, etc.). If the minimum operating power is larger (sensitivity X) and smaller (sensitivity Y), the maximum detection distances are different from raX and raY even with the same transmission power A. Even if the antenna on the moving body transmits with the same power, the maximum detection distance differs depending on the radio signal transmitting means, so it is difficult to confirm the relative position between the antenna and the radio signal transmitting means.
一方，上記のように電波信号発信手段の受信感度におけるバラツキとは別に，配置された複数の電波信号発信手段に沿ってアンテナを移動させ，電波信号発信手段との通信状態から電波信号発信手段の位置を観測する場合，上記アンテナに複数の電波信号発信手段からの信号が同時に到達してしまうため，アンテナで観測された電波がどの電波信号発信手段から発信されたものかの弁別が出来ず，電波信号発信手段の位置測定が正確に出来ない問題が生じる。
無線タグのような電波信号発信手段を一定距離を置いて直線的に配置し，アンテナを備えた移動体が上記一列に並べられた電波信号発信手段に沿って移動して，検出される電波信号発信手段により両者の相対位置を検出する場合を模式図として示したのが図２である。
移動体が矢印方向に移動した場合，検出領域も移動し，次々と異なる電波信号発信手段（図ではタグと表示する）を検出する。
図の（ａ），（ｂ），（ｃ）は，アンテナ側の検出領域の大きさが変化した場合を示している。
（ａ）は，検出領域の大きさが，電波信号発信手段の間隔より大きい場合で，同時に複数の電波信号発信手段が検出されるために，電波信号発信手段とアンテナとの対応関係が曖昧となり，相対的な位置関係を正確に測定することが出来ない。
（ｂ）は，検出領域が電波信号発信手段の間隔と同じ大きさの場合である。この場合には，境界点を除き，同時に１個の電波信号発信手段しか検出しないので，電波信号発信手段とアンテナとの相対位置を測定するには適しているが，境界点において２つの電波信号発信手段を同時に検出してしまうので，その場合に特殊な処理を必要とする問題がある。
さらに（ｃ）は，検出領域の大きさが電波信号発信手段の間隔より狭いので，複数の電波信号発信手段を同時に検出することはないが，１個も検出しない状況も生じるため，位置検出の手段としては適していない。
On the other hand, apart from the variation in the reception sensitivity of the radio signal transmitting means as described above, the antenna is moved along a plurality of arranged radio signal transmitting means and the radio signal transmitting means is changed from the communication state with the radio signal transmitting means. When observing the position, signals from a plurality of radio signal transmitting means arrive at the antenna at the same time, so it is impossible to discriminate which radio signal transmitting means the radio waves observed by the antenna are transmitted from. There arises a problem that the position of the radio signal transmitting means cannot be accurately measured.
Radio wave signal transmission means such as a radio tag is linearly arranged at a fixed distance, and a mobile object equipped with an antenna moves along the radio signal transmission means arranged in a row to detect the radio signal FIG. 2 shows the case where the relative position of both is detected by the transmitting means as a schematic diagram.
When the moving body moves in the direction of the arrow, the detection area also moves to detect different radio signal transmission means (indicated as tags in the figure).
(A), (b), (c) of the figure shows a case where the size of the detection area on the antenna side has changed.
(A) is a case where the size of the detection area is larger than the interval between the radio signal transmitting means, and since a plurality of radio signal transmitting means are detected at the same time, the correspondence between the radio signal transmitting means and the antenna becomes ambiguous. , The relative positional relationship cannot be measured accurately.
(B) is a case where the detection area has the same size as the interval of the radio signal transmitting means. In this case, since only one radio signal transmitting means is detected at the same time except for the boundary point, it is suitable for measuring the relative position between the radio signal transmitting means and the antenna. Since the transmission means are detected at the same time, there is a problem that requires special processing.
Furthermore, in (c), since the size of the detection area is narrower than the interval between the radio signal transmission means, a plurality of radio signal transmission means are not detected at the same time. It is not suitable as a means.
即ち，通信手段から発信する電波信号の出力を減少させることによって，同時に起動される電波信号発信手段の数を減らすことができるが，通信手段から発信された電波信号が何れの電波信号発信手段にも受信されず，何れの電波信号発信手段から電波信号が発信され状態が生じる可能性があるために，位置検出手段に何れの無線タグの識別情報も受信されず，このために移動体の位置の検出ができない場合が生じて実用的でない。 That is, by reducing the output of the radio signal transmitted from the communication means, the number of radio signal transmission means activated simultaneously can be reduced. However, the radio signal transmitted from the communication means is assigned to any radio signal transmission means. Since no radio wave signal is transmitted from any radio wave signal transmitting means and the state may occur, the position detection means does not receive any RFID tag identification information. This is not practical because it may not be detected.
従って，本発明は上記事情に鑑みてなされたものであり，その目的とするところは，移動体側のアンテナが，複数の電波信号発信手段と通信しうる距離関係になった場合にも，複数の電波信号発信手段との混信を生じることがないように配慮されることで，電波信号発信手段と移動体との相対位置検出を誤りなく行ないうると共に，簡単な手段で正確に相対位置を検出することの出来る位置検出システムを提供することにある。 Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to provide a plurality of antennas even when the mobile antenna has a distance relationship with which a plurality of radio signal transmitting means can communicate. By taking care not to cause interference with radio signal transmission means, the relative position between the radio signal transmission means and the moving object can be detected without error, and the relative position can be accurately detected with simple means. It is to provide a position detection system capable of performing the above.
上記目的を達成するために本発明は，
一定の間隔で設けられた複数の電波信号発信手段と，
前記複数の電波信号発信手段に対して相対的に移動する移動体に搭載され，所定の電波信号を受信可能な複数のアンテナを備えた通信手段と，
を具備する位置検出システムであって，
前記電波信号発信手段は，前記通信手段のアンテナから送信された通信要求に応じて各電波信号発信手段に固有の識別情報を含む電波信号を発信するものであり，前記通信手段のアンテナが受信する上記所定の電波信号は，前記各電波信号発信手段から発信された各電波信号発信手段に固有の識別情報を含む電波信号である位置検出システムにおいて，
前記通信手段から上記電波信号発信手段への前記通信要求を含む電波信号の送信電力を変化させることによって，１つの電波信号発信手段と上記アンテナとの間で通信可能な限界の送信電力を検出する限界送信電力検出手段と，
前記限界送信電力検出手段により検出された１つの電波信号発信手段と各々のアンテナとの間で通信可能な限界の送信電力から演算される各々のアンテナと上記１つの電波信号発信手段との距離の比率から前記アンテナと前記電波信号発信手段との相対位置を検出する位置検出手段と，
を備えてなることを特徴とする位置検出システムである。
In order to achieve the above object, the present invention provides:
A plurality of radio signal transmission means provided at regular intervals;
A communication means mounted on a moving body that moves relative to the plurality of radio signal transmission means, and comprising a plurality of antennas capable of receiving a predetermined radio signal;
A position detection system comprising:
The radio signal transmitting means transmits a radio signal including identification information unique to each radio signal transmitting means in response to a communication request transmitted from the antenna of the communication means, and is received by the antenna of the communication means. In the position detection system, the predetermined radio signal is a radio signal including identification information unique to each radio signal transmitter transmitted from each radio signal transmitter.
By detecting the transmission power of the radio signal including the communication request from the communication means to the radio signal transmission means, the limit transmission power that can be communicated between one radio signal transmission means and the antenna is detected. Limit transmission power detection means;
The distance between each antenna calculated from the limit transmission power communicable between each antenna and the one radio signal transmission means detected by the limit transmission power detection means and the one radio signal transmission means. Position detecting means for detecting a relative position between the antenna and the radio signal transmitting means from a ratio;
It is a position detection system characterized by comprising.
上記本発明の位置検出システムによれば，常に１つの電波信号発信手段と上記アンテナとの間で通信可能な限界の送信電力を検出するものであるので，上記１つの電波信号発信手段とアンテナとの位置関係だけを演算することが出来，複数の電波信号発信手段がもつ感度のバラツキなどに影響を受けずに位置を正確に算定できる。
また，前記通信手段上の上記電波信号発信手段への送信電力を変化させることによって，１つの電波信号発信手段と上記アンテナとの間で通信可能な限界の送信電力を検出し，検出された１つの電波信号発信手段と各々のアンテナとの間で通信可能な限界の送信電力から演算される各々のアンテナと上記１つの電波信号発信手段との距離の比率から前記アンテナと前記電波信号発信手段との相対位置を検出するものであるから，各アンテナの出力のバラツキなどに影響されることなく，電波信号発信手段との間の相対位置を正確に検出することが出来る。
According to the position detection system of the present invention, the limit transmission power that can be communicated between one radio signal transmitting means and the antenna is always detected. Therefore, the one radio signal transmitting means, the antenna, The position can be calculated accurately without being affected by variations in sensitivity of a plurality of radio signal transmission means.
Further, by changing the transmission power to the radio signal transmission means on the communication means, the limit transmission power that can be communicated between one radio signal transmission means and the antenna is detected. From the ratio of the distance between each antenna and the one radio signal transmission means calculated from the limit transmission power that can be communicated between the two radio signal transmission means and each antenna, the antenna and the radio signal transmission means Therefore, it is possible to accurately detect the relative position to the radio wave signal transmitting means without being affected by variations in the output of each antenna.
具体的な構成においては，前記位置検出手段が，前記複数のアンテナからの送信電力を同じにしながら順次減少させ，いずれか，あるいは複数の前記アンテナで前記電波信号発信手段との間の通信を検出することが出来なくなった時点における各限界の送信電力の比率から，前記アンテナと前記電波信号発信手段との相対位置を検出するものが提案される。
このような手法によって確実に上記相対位置が取得される。
In a specific configuration, the position detection unit sequentially decreases the transmission power from the plurality of antennas while maintaining the same, and detects communication with the radio signal transmission unit by any one or a plurality of the antennas. It is proposed to detect the relative position between the antenna and the radio signal transmission means from the ratio of the transmission power at each limit when it is no longer possible.
The relative position is reliably acquired by such a method.
対象を１つの電波信号発信手段に絞って制御する方法として，電波信号発信手段間の間隔とアンテナ間の間隔をほぼ等しく設定すると共に，前記限界送信電力検出手段が，移動体に設けられた複数のアンテナを切換えながら各限界の送信電力を測定するものが考えられる。
また別の方法としては，前記限界送信電力検出手段が，前記電波信号発信手段ごとに定められた固有の識別情報を確認すると共に，前記通信手段上の上記電波信号発信手段への送信電力を変化させるものが提案される。
As a method of controlling a target to be limited to one radio signal transmitting means, the interval between the radio signal transmitting means and the interval between the antennas are set to be approximately equal, and the limit transmission power detection means is provided in a plurality of units provided on the moving body. It is possible to measure the transmission power at each limit while switching the antennas.
As another method, the limit transmission power detection means confirms the unique identification information determined for each radio signal transmission means, and changes the transmission power to the radio signal transmission means on the communication means. What is to be proposed is proposed.
更に，前記移動体を２次元的に移動させることで，電波信号発信手段の位置を２次元的に検出するものであれば，本発明を２次元位置の検出にも応用出来る。 Furthermore, the present invention can be applied to the detection of a two-dimensional position as long as the position of the radio wave signal transmitting means is detected two-dimensionally by moving the moving body two-dimensionally.
前記電波信号発信手段の適用例として，パッシブ型の無線タグが考えられる。
また必ずしもパッシブ型でなくても，通信手段のアンテナから送信された通信要求に応じて各電波信号発信手段に固有の識別情報を含む電波信号を発信するものであり，前記通信手段のアンテナが受信する上記所定の電波信号は，前記各電波信号発信手段から発信された各電波信号発信手段に固有の識別情報を含む電波信号である無線タグであればよい。
As an application example of the radio signal transmitting means, a passive type radio tag can be considered.
Further, even if it is not necessarily a passive type, it transmits a radio signal including identification information unique to each radio signal transmitting means in response to a communication request transmitted from the antenna of the communication means. The predetermined radio signal may be a radio tag that is a radio signal including identification information unique to each radio signal transmission means transmitted from each radio signal transmission means.
上記本発明の位置検出システムによれば，１つの電波信号発信手段と上記アンテナとの間で通信可能な限界の送信電力を検出するものであるので，上記１つの電波信号発信手段とアンテナとの位置関係だけを演算することが出来，複数の電波信号発信手段がもつ感度のバラツキなどに影響を受けずに位置を正確に算定できる。 According to the position detection system of the present invention, the limit transmission power that can be communicated between one radio signal transmission means and the antenna is detected. Only the positional relationship can be calculated, and the position can be accurately calculated without being affected by variations in sensitivity of the plurality of radio signal transmitting means.
また，前記通信手段上の上記電波信号発信手段への送信電力を変化させることによって，１つの電波信号発信手段と上記アンテナとの間で通信可能な限界の送信電力を検出し，検出された１つの電波信号発信手段と各々のアンテナとの間で通信可能な限界の送信電力から演算される各々のアンテナと上記１つの電波信号発信手段との距離の比率から前記アンテナと前記電波信号発信手段との相対位置を検出するものであるから，各アンテナの出力のバラツキなどに影響されることなく，電波信号発信手段との間の相対位置を正確に検出することが出来る。 Further, by changing the transmission power to the radio signal transmission means on the communication means, the limit transmission power that can be communicated between one radio signal transmission means and the antenna is detected. From the ratio of the distance between each antenna and the one radio signal transmission means calculated from the limit transmission power that can be communicated between the two radio signal transmission means and each antenna, the antenna and the radio signal transmission means Therefore, it is possible to accurately detect the relative position to the radio wave signal transmitting means without being affected by variations in the output of each antenna.
以下添付図面を参照しながら，本発明の実施の形態について説明し，本発明の理解に供する。尚，以下の実施の形態は，本発明を具体化した一例であって，本発明の技術的範囲を限定する性格のものではない。
ここに，図１は，電波信号発信手段の受信電力と，電波信号発信手段と移動体のアンテナとの距離との関係を示すグラフ，図２は，移動する移動体の検出領域と電波信号発信手段の位置との関係を示す図，図３は，本発明の一実施形態に係るシステムの原理を説明するためのアンテナと電波信号発信手段の関係を示す図，図４は，本発明の一実施形態に係るシステムの動作説明するためのアンテナと電波信号発信手段の関係を示す図，図５は，本発明の一実施形態に係るシステムの動作説明するためのアンテナと電波信号発信手段の関係を示す図，図６は，本発明の一実施形態に係るシステムを２次元平面における位置検出装置に適用した場合のアンテナと電波信号発信手段の関係を示す図である。
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a graph showing the relationship between the reception power of the radio signal transmitting means and the distance between the radio signal transmitting means and the mobile antenna, and FIG. 2 is the detection area of the moving mobile body and the radio signal transmission. FIG. 3 is a diagram showing the relationship between the position of the means, FIG. 3 is a diagram showing the relationship between the antenna and the radio signal transmitting means for explaining the principle of the system according to one embodiment of the present invention, and FIG. FIG. 5 is a diagram showing the relationship between an antenna and radio signal transmitting means for explaining the operation of the system according to the embodiment, and FIG. 5 is a diagram showing the relationship between the antenna and radio signal transmitting means for explaining the operation of the system according to one embodiment of the present invention. FIG. 6 is a diagram showing the relationship between the antenna and the radio signal transmission means when the system according to one embodiment of the present invention is applied to a position detection device in a two-dimensional plane.
本発明に係る以下の実施形態の位置検出システムは，基本的に，固有の識別情報を含む電波信号を発信する複数の電波信号発信手段が一定の間隔で設けられ，この電波信号発信手段に対して相対的に移動する移動体に，各前記電波信号発信手段から発信された前記固有の識別情報を含む電波信号を受信可能な複数のアンテナを備えた通信手段が設けられてなる位置検出システムに関するものであり，前記通信手段から上記電波信号発信手段への送信電力を変化させることによって，１つの電波信号発信手段と上記アンテナとの間で通信可能な限界の送信電力を検出し，検出された１つの電波信号発信手段と各々のアンテナとの間で通信可能な限界の送信電力から演算される各々のアンテナと上記１つの電波信号発信手段との距離の比率から前記アンテナと前記電波信号発信手段との相対位置を検出するものである。
以下，この実施形態に係る位置検出原理を詳しく説明する。
In the position detection system according to the following embodiment of the present invention, basically, a plurality of radio signal transmitting means for transmitting radio signals including unique identification information are provided at regular intervals. In particular, the present invention relates to a position detection system in which a moving body relatively moving is provided with communication means including a plurality of antennas capable of receiving radio signal including the unique identification information transmitted from the radio signal transmission means. By changing the transmission power from the communication means to the radio signal transmission means, the limit transmission power that can be communicated between one radio signal transmission means and the antenna is detected and detected. From the ratio of the distance between each antenna and the one radio signal transmission means calculated from the limit transmission power that can be communicated between one radio signal transmission means and each antenna And it detects the relative position of the antenna and the radio signal transmitter.
Hereinafter, the position detection principle according to this embodiment will be described in detail.
この実施形態にかかる位置検出システムは，図３のように固有の識別情報を含む電波信号を発信する複数の電波信号発信手段（■で示す）が一定の間隔で設けられ，この電波信号発信手段に対して相対的に移動する移動体（不図示）に，各前記電波信号発信手段から発信された前記固有の識別情報を含む電波信号を受信可能な複数のアンテナ（アンテナ１，アンテナ２）を備えた通信手段が設けられてなる位置検出システムである。
上記のように移動体に設けられた通信手段から上記電波信号発信手段への送信電力を変化させることによって，１つの電波信号発信手段と上記アンテナとの間で通信可能な限界の送信電力を検出する。このような限界の送信電力を検出するのが限界送信電力検出手段の一例である。
そのためには，同一の電波信号発信手段と，移動体に設けられた複数のアンテナとの間で通信する必要がある。この場合，前記したように，各々のアンテナから電波信号発信手段までの距離が異なれば，検出の状態，特にアンテナから電波信号発信手段に届く送信電力が変化する。
この距離の相違によって変化する「アンテナから電波信号発信手段に届く送信電力」を計測するために，上記送信電力を電波信号発信手段が検出している状態で徐々に送信電力を低下させ，各アンテナが電波信号発信手段を検出できる限界までそれぞれ下げる。この時の移動体側で測定される送信電力を限界送信電力ＰＷｎ（ｎはアンテナの番号）と呼ぶことにする。
この限界の状態では，各アンテナが同じ１つの電波信号発信手段に通信要求などの電波信号を送信しているのであれば，各アンテナの限界上体でタグに到達している電力は同じのはずである。この電波信号発信手段に到達している限界電力を最小動作電力ＰＷｍｉｎと呼ぶことにする。
一方，電波信号発信手段に到達する電力は距離の２乗に反比例するので，複数のアンテナの限界送信電力ＰＷｎ（ＰＷ１，ＰＷ２，ＰＷ３，…），各アンテナから上記１つの電波信号発信手段までの距離Ｌｎ（Ｌ１，Ｌ２，Ｌ３，…），電波信号発信手段の最小動作電力ＰＷｍｉｎの間には，以下の関係が成り立つ。
ＰＷ１／（Ｌ１2）＝ＰＷ２／（Ｌ２2）＝ＰＷ３／（Ｌ３2）＝…＝ＰＷｍｉｎ
これより，
Ｌ１＝√（ＰＷ１／ＰＷｍｉｎ），Ｌ２＝√（ＰＷ２／ＰＷｍｉｎ），Ｌ３＝√（ＰＷ３／ＰＷｍｉｎ）… （１）
が成り立つ。
In the position detection system according to this embodiment, as shown in FIG. 3, a plurality of radio signal transmitting means (indicated by ■) that transmit radio signals including unique identification information are provided at regular intervals. A plurality of antennas (
As described above, by changing the transmission power from the communication means provided on the moving body to the radio signal transmission means, the limit transmission power that can be communicated between one radio signal transmission means and the antenna is detected. To do. An example of limit transmission power detection means detects such limit transmission power.
For this purpose, it is necessary to communicate between the same radio wave signal transmitting means and a plurality of antennas provided on the moving body. In this case, as described above, if the distance from each antenna to the radio signal transmitting means is different, the detection state, in particular, the transmission power reaching the radio signal transmitting means from the antenna changes.
In order to measure the “transmission power reaching the radio signal transmission means from the antenna” which changes due to the difference in distance, the transmission power is gradually reduced while the radio signal transmission means is detecting the transmission power, and each antenna is Lower to the limit at which the radio signal transmitting means can be detected. The transmission power measured on the mobile side at this time will be referred to as limit transmission power PWn (n is the antenna number).
In this limit state, if each antenna transmits a radio signal such as a communication request to the same radio signal transmission means, the power reaching the tag in the upper limit of each antenna should be the same. It is. The limit power that has reached the radio signal transmitting means will be referred to as the minimum operating power PWmin.
On the other hand, since the power reaching the radio signal transmitting means is inversely proportional to the square of the distance, the limit transmission power PWn (PW1, PW2, PW3,...) Of a plurality of antennas, from each antenna to the one radio signal transmitting means. The following relationship is established between the distance Ln (L1, L2, L3,...) And the minimum operating power PWmin of the radio signal transmitting means.
PW1 / (L1 2 ) = PW2 / (L2 2 ) = PW3 / (L3 2 ) =... = PWmin
Than this,
L1 = √ (PW1 / PWmin), L2 = √ (PW2 / PWmin), L3 = √ (PW3 / PWmin) (1)
Holds.
ＰＷｍｉｎは，同一の電波信号発信手段に送信している状態では一定であり，（１）式の各項に共通に含まれ，またＰＷ１，ＰＷ２，ＰＷ３，…は，それぞれ検出される値であるので，上記（１）式からＬ１，Ｌ２，Ｌ３，…の比率が求まる。
移動体に設けられているアンテナ間の距離は既知であるので，１つの電波信号発信手段についての各アンテナの上記限界送信電力ＰＷｎ（ＰＷ１，ＰＷ２，ＰＷ３，…）を検出すれば，上記Ｌ１，Ｌ２，Ｌ３，…の比率が求まり，アンテナ間の距離は既知であるので，それによって既知のアンテナ間距離を上記Ｌ１，Ｌ２，Ｌ３，…の比率で按分することで，アンテナ−電波信号発信手段間の距離が分かる。
このように検出された１つの電波信号発信手段と各々のアンテナとの間で通信可能な限界の送信電力から演算される各々のアンテナと上記１つの電波信号発信手段との距離の比率から前記アンテナと前記電波信号発信手段との相対位置を検出するのが，本発明における位置検出手段の一例である。
PWmin is constant when it is transmitted to the same radio wave signal transmitting means, and is commonly included in each term of equation (1), and PW1, PW2, PW3,. Therefore, the ratio of L1, L2, L3,... Is obtained from the above equation (1).
Since the distance between the antennas provided in the moving body is known, if the limit transmission power PWn (PW1, PW2, PW3,...) Of each antenna for one radio signal transmitting means is detected, the above L1, Since the ratio of L2, L3,... Is obtained and the distance between the antennas is known, the antenna-radio signal transmitting means is divided by dividing the known distance between the antennas by the ratio of L1, L2, L3,. You can see the distance between them.
From the ratio of the distance between each antenna and the one radio signal transmitting means calculated from the limit transmission power that can be communicated between the one radio signal transmitting means and each antenna thus detected, the antenna An example of the position detecting means in the present invention is to detect the relative position between the radio signal transmitting means and the radio signal transmitting means.
簡略化された手法として，次のようなものでも一応の目的は達成される。
２台のアンテナを備えた移動体を想定する。２台のアンテナの並びの方向と，電波信号発信手段の並びの方向が一致している図３のような状態では，アンテナ１とアンテナ２の間隔Ｐを√（ＰＷ１／ＰＷｍｉｎ）：√（ＰＷ２／ＰＷｍｉｎ）の比に按分することで，アンテナ１及び２と，その間にある電波信号発信手段との距離（電波信号発信手段の並びに沿った方向の距離）Ｌ１及びＬ２を算出することが出来る。
As a simplified method, the following purpose can be achieved even with the following.
Assume a moving object with two antennas. In the state shown in FIG. 3 in which the arrangement direction of the two antennas and the arrangement direction of the radio signal transmitting means coincide with each other, the interval P between the
上の（１）式が成立するためには，前提として１つの電波信号発信手段に対して複数のアンテナが電波を送信することが必要である。即ち，複数の電波信号発信手段が存在する状態では，アンテナは，隣接する電波信号発信手段との間でも通信が同時に成立してしまい，正確に距離を計測することが出来ない。
上記のように，位置が検出できないという事態を回避するためには，電波信号発信手段間隔がアンテナの検出領域の大きさ以下の必要がある（電波信号発信手段間隔≦検出領域：条件１）。電波信号発信手段間隔≦検出領域 であれば，２個電波信号発信手段が同時に検出される場合が生じる。２個の電波信号発信手段が同時に検出される領域の大きさは，（検出領域−電波信号発信手段間隔）であるので，これを小さくするには検出領域を小さくする必要があるが，上記の条件１の制約から，
電波信号発信手段間隔＝検出領域
が限界となる。この場合，２個の電波信号発信手段の真ん中でのみ電波信号発信手段が２個検出される。しかしその場合，そこへ移動するまでは他の電波信号発信手段を検出していたはずで，その経過からどの電波信号発信手段の場所からどの電波信号発信手段の場所へ移動体が移動したかは分かるので，移動体の移動軌跡が分からなくなること，つまり迷子になることはない。
即ち，同時に２個検出された時点まではその１個前のタグ（１，２とあって１→１＆２→２，ならば，１＆２は１とする），あるいは次のタグ（１，２とあって１→１＆２→２，ならば，１＆２は２とする）と定義すればよく（四捨五入の切り上げをどこからするかと類似），２個検出される領域は非常に限定されるので問題はない。
In order for the above equation (1) to hold, it is necessary that a plurality of antennas transmit radio waves to one radio signal transmission means. That is, in the state where there are a plurality of radio signal transmitting means, the antenna can simultaneously establish communication with the adjacent radio signal transmitting means, and the distance cannot be measured accurately.
As described above, in order to avoid the situation where the position cannot be detected, the interval between the radio signal transmission means needs to be equal to or smaller than the size of the detection area of the antenna (radio signal transmission means interval ≦ detection area: condition 1). If radio wave signal transmitting means interval ≦ detection region, two radio signal transmitting means may be detected at the same time. Since the size of the area where the two radio signal transmitting means are simultaneously detected is (detection area-radio signal transmitting means interval), it is necessary to reduce the detection area in order to reduce this, From the constraint of
Radio signal transmission means interval = detection area is a limit. In this case, two radio signal transmitting means are detected only in the middle of the two radio signal transmitting means. However, in that case, other radio signal transmission means should have been detected until moving there, and from which time the radio signal transmission means was moved to which radio signal transmission means. As you can see, the moving trajectory of the moving object is not understood, that is, it is not lost.
That is, up to the point when two are detected at the same time, the previous tag (1, 2 and 1 → 1 & 2 → 2, if 1 & 2 is 1,) or the next tag (1, 2 and so on). If 1 → 1 & 2 → 2, then 1 & 2 is defined as 2) (similar to where rounding is rounded up), and there is no problem because the two detected areas are very limited.
この原理にならってこの実施形態では，２台のアンテナの間隔を，図３に示すように，電波信号発信手段の間隔に等しくする。
前記したように，あまり離しては同一の電波信号発信手段を検出できない。また，電波信号発信手段の間隔より狭いといずれのアンテナも電波信号発信手段と通信できない状態が生じて，検出不可能になる。
このような不都合を回避するために，２台のアンテナの間隔は，図３に示すように，電波信号発信手段の間隔に等しくする。
この場合，例外的に，同時に２つの電波信号発信手段からの電波を検出してしまうことがあり得るが，前記のように移動体の移動軌跡は連続しているので，途中で迷子になることはない。
In accordance with this principle, in this embodiment, the interval between the two antennas is made equal to the interval between the radio signal transmitting means as shown in FIG.
As described above, the same radio signal transmission means cannot be detected if they are too far apart. If the distance between the radio signal transmitting means is narrower, any antenna cannot communicate with the radio signal transmitting means and cannot be detected.
In order to avoid such inconvenience, the interval between the two antennas is made equal to the interval between the radio signal transmitting means as shown in FIG.
In this case, the radio waves from the two radio signal transmission means may be detected at the same time, but the moving trajectory of the moving body is continuous as described above, so it may be lost along the way. There is no.
また１つの電波信号発信手段からの信号のみを検出対象とするための別の方法として，電波信号発信手段と各アンテナの間で，各アンテナから各電波信号発信手段への送信電力を変化させて，電波信号発信手段と各アンテナとの間で通信するときに，前記電波信号発信手段ごとに定められた固有の識別情報を確認すると共に，前記通信手段上の上記電波信号発信手段への送信電力を変化させるようにしてもよい。このように，通信中に相手の固有の識別情報（ＩＤ）を確認して特定の固有の識別情報を備えた電波信号発信手段との間でのみ上記電波信号発信手段への送信電力を変化させるようにするので，通信相手が１つの電波信号発信手段に絞られ，前記（１）式が成立することになる。
このようにして，上記複数のアンテナに対する上記１個の電波信号発信手段の位置が確定する。これを他の電波信号発信手段についても繰り返すことで，電波信号発信手段がいくつあっても簡単にその１次元的，２次元的，場合によっては３次元的配置を測定することが出来る。
Another method for detecting only the signal from one radio signal transmission means is to change the transmission power from each antenna to each radio signal transmission means between the radio signal transmission means and each antenna. , When communicating between the radio signal transmitting means and each antenna, the unique identification information determined for each radio signal transmitting means is confirmed, and the transmission power to the radio signal transmitting means on the communication means is confirmed. May be changed. Thus, the transmission power to the radio signal transmitting means is changed only with the radio signal transmitting means having specific specific identification information by confirming the specific identification information (ID) of the other party during communication. Therefore, the communication partner is narrowed down to one radio signal transmission means, and the above equation (1) is established.
In this way, the position of the one radio signal transmitting means with respect to the plurality of antennas is determined. By repeating this for other radio signal transmitting means, it is possible to easily measure the one-dimensional, two-dimensional, and in some cases three-dimensional arrangements, regardless of the number of radio signal transmitting means.
また送信電力を変化させる点について，簡単には以下のような方法でも実施可能である。
２台のアンテナの間に電波信号発信手段があるとする。
両アンテナを同一の送信電力で動作させ，徐々に送信電力を低下させる。電波信号発信手段での受信電力の差により，電波信号発信手段までの距離が遠いアンテナ側で先に電波の検出が出来なくなる。電波信号発信手段が２つのアンテナのちょうど真ん中にあれば，同時に検出できなくなる。
このようにしてどちらのアンテナが先に検出できなくなるかで，電波信号発信手段の位置がどちらのアンテナに近い位置にあるかを判定できる。即ち，電波信号発信手段がどちらのアンテナの近く（アンテナ間隔の半分の距離内）にあるかどうかが少なくとも判定出来る。
図４に示すように，アンテナ間隔を電波信号発信手段間隔Ｐに等しくすれば，特定の電波信号発信手段が特定のアンテナから両側Ｐ／２の範囲内にあるかを判定でき，あるアンテナに近い位置にある電波信号発信手段が一義的に決定できる。
Further, it is possible to simply change the transmission power by the following method.
It is assumed that there is a radio signal transmitting means between the two antennas.
Operate both antennas with the same transmission power and gradually decrease the transmission power. Due to the difference in received power at the radio signal transmitting means, it becomes impossible to detect the radio wave first on the antenna side far from the radio signal transmitting means. If the radio signal transmission means is in the middle of the two antennas, it cannot be detected simultaneously.
In this way, it is possible to determine which antenna is closer to the position of the radio wave signal transmitting means depending on which antenna cannot be detected first. That is, it can be determined at least whether the radio wave signal transmitting means is near which antenna (within half the distance between the antennas).
As shown in FIG. 4, if the antenna interval is made equal to the radio signal transmitting means interval P, it can be determined whether the specific radio signal transmitting means is within the range of P / 2 on both sides from the specific antenna. The radio signal transmitting means at the position can be uniquely determined.
アンテナ２台では，電波信号発信手段がアンテナ間になければ，電波信号発信手段を特定出来ないように見えるが，電波信号発信手段が等間隔に並んでいるので，図５に示すように，隣接する電波信号発信手段どちらかが（左右に並んでいるとして，右隣，あるいは左隣の意味）アンテナ間にあり，それより特定の電波信号発信手段がアンテナのＰ／２の範囲内にあるかを判定できる。
もちろん，３台のアンテナを間隔Ｐずつで並べ，真ん中のアンテナと別のアンテナどちらかとの２通りの組み合わせで判定し，真ん中のアンテナから±Ｐ／２にある電波信号発信手段を確定することも出来る。
以上述べたすべての場合について，２つのアンテナの測定情報に混乱を生じないように，検出系での演算や判定が完了するまで，移動体に設けられた複数のアンテナを切換えながら各限界の送信電力を測定することが望ましい。
With two antennas, if the radio signal transmitting means is not between the antennas, it seems that the radio signal transmitting means cannot be specified. However, since the radio signal transmitting means are arranged at equal intervals, as shown in FIG. Which radio signal transmission means to perform is between antennas (assuming they are arranged side by side on the left and right), and whether the specific radio signal transmission means is within the P / 2 range of the antenna. Can be determined.
Of course, three antennas can be arranged at intervals of P, and judgment can be made with two combinations of the middle antenna and another antenna, and the radio signal transmission means within ± P / 2 from the middle antenna can be determined. I can do it.
In all the cases described above, transmission of each limit is performed while switching the multiple antennas provided in the moving object until the calculation and determination in the detection system are completed so that the measurement information of the two antennas is not confused. It is desirable to measure power.
上記実施形態に係る装置を２次元平面上の電波信号発信手段に適用することも可能である。
例えば，図６に示すように，３台のアンテナ（１，２，３）を直線上に並ばないように配置し，上記３台のアンテナを一体として２次元平面に沿って移動させる。この時に，３台のアンテナの内の２台について前記したように固有情報によって１個の電波信号発信手段に絞って限界動作電力を検出し，上記２台のアンテナからの距離を測定し，続けて，上記２台のアンテナの並びに対して直角の方向に並んでいる２台のアンテナについて先に測定した電波信号発信手段との距離を同様に測定すれば，アンテナに対する上記１個の電波信号発信手段の位置が確定する。これを他の電波信号発信手段についても繰り返すことで，電波信号発信手段がいくつあっても簡単にその２次元的配置を測定することが出来る。
It is also possible to apply the apparatus according to the above-described embodiment to radio wave signal transmitting means on a two-dimensional plane.
For example, as shown in FIG. 6, the three antennas (1, 2, 3) are arranged so as not to be aligned on a straight line, and the three antennas are moved together along a two-dimensional plane. At this time, for two of the three antennas, as described above, the limit operating power is detected by narrowing down to one radio wave signal transmission means based on the unique information, the distance from the two antennas is measured, and then Thus, if the distance between the two antennas arranged in the direction perpendicular to the arrangement of the two antennas and the radio signal transmitting means previously measured is similarly measured, the one radio signal transmission to the antenna is performed. The position of the means is determined. By repeating this for other radio signal transmitting means, the two-dimensional arrangement can be easily measured regardless of the number of radio signal transmitting means.
前記電波信号発信手段は，種々の形式が考えられるが，例えば，パッシブ型の無線タグや共振型の無線タグに本発明は適用可能である。 The radio wave signal transmitting means may be in various forms. For example, the present invention can be applied to a passive type wireless tag and a resonance type wireless tag.
本発明は，無線タグ等の電波発信手段を用いた移動体の位置検出，或いは倉庫における収納位置の検出等に利用できるものである。 INDUSTRIAL APPLICABILITY The present invention can be used for detecting the position of a moving body using radio wave transmission means such as a wireless tag, or detecting a storage position in a warehouse.
Ｐ…電波信号発信手段の間隔
Ｌ１，Ｌ２…電波信号発信手段とアンテナの距離
P: Distance between radio signal transmitting means L1, L2: Distance between radio signal transmitting means and antenna
Claims (5)
前記複数の電波信号発信手段に対して相対的に移動する移動体に搭載され，所定の電波信号を受信可能な複数のアンテナを備えた通信手段と，
を具備する位置検出システムであって，
前記電波信号発信手段は，前記通信手段のアンテナから送信された通信要求に応じて各電波信号発信手段に固有の識別情報を含む電波信号を発信するものであり，前記通信手段のアンテナが受信する上記所定の電波信号は，前記各電波信号発信手段から発信された各電波信号発信手段に固有の識別情報を含む電波信号である位置検出システムにおいて，
前記通信手段から上記電波信号発信手段への前記通信要求を含む電波信号の送信電力を変化させることによって，１つの電波信号発信手段と上記アンテナとの間で通信可能な限界の送信電力を検出する限界送信電力検出手段と，
前記限界送信電力検出手段により検出された１つの電波信号発信手段と各々のアンテナとの間で通信可能な限界の送信電力から演算される各々のアンテナと上記１つの電波信号発信手段との距離の比率から前記アンテナと前記電波信号発信手段との相対位置を検出する位置検出手段と，
を備えてなることを特徴とする位置検出システム。 A plurality of radio signal transmission means provided at regular intervals;
A communication means mounted on a moving body that moves relative to the plurality of radio signal transmission means, and comprising a plurality of antennas capable of receiving a predetermined radio signal;
A position detection system comprising:
The radio signal transmitting means transmits a radio signal including identification information unique to each radio signal transmitting means in response to a communication request transmitted from the antenna of the communication means, and is received by the antenna of the communication means. In the position detection system, the predetermined radio signal is a radio signal including identification information unique to each radio signal transmitter transmitted from each radio signal transmitter.
By detecting the transmission power of the radio signal including the communication request from the communication means to the radio signal transmission means, the limit transmission power that can be communicated between one radio signal transmission means and the antenna is detected. Limit transmission power detection means;
The distance between each antenna calculated from the limit transmission power communicable between each antenna and the one radio signal transmission means detected by the limit transmission power detection means and the one radio signal transmission means. Position detecting means for detecting a relative position between the antenna and the radio signal transmitting means from a ratio;
A position detection system comprising:
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| JP2007246506A JP2009075032A (en) | 2007-09-25 | 2007-09-25 | Location detection system |
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| Application Number | Priority Date | Filing Date | Title |
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| JP2007246506A JP2009075032A (en) | 2007-09-25 | 2007-09-25 | Location detection system |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010256295A (en) * | 2009-04-28 | 2010-11-11 | Fujitsu Ltd | Positioning system |
| JP2014134387A (en) * | 2013-01-08 | 2014-07-24 | Mitsubishi Electric Corp | Position detection system |
| JP2015516564A (en) * | 2012-03-07 | 2015-06-11 | コミサリア ア レネルジ アトミクエ オウ エネルジ アルタナティヴ | Positioning device for evaluating the distance between an RFID tag and an interface |
-
2007
- 2007-09-25 JP JP2007246506A patent/JP2009075032A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010256295A (en) * | 2009-04-28 | 2010-11-11 | Fujitsu Ltd | Positioning system |
| JP2015516564A (en) * | 2012-03-07 | 2015-06-11 | コミサリア ア レネルジ アトミクエ オウ エネルジ アルタナティヴ | Positioning device for evaluating the distance between an RFID tag and an interface |
| JP2014134387A (en) * | 2013-01-08 | 2014-07-24 | Mitsubishi Electric Corp | Position detection system |
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