JP2008005120A

JP2008005120A - Vehicle communication system with noise radio wave direction detecting and reducing functions

Info

Publication number: JP2008005120A
Application number: JP2006171412A
Authority: JP
Inventors: Akira Fushimi; 晃伏見; Yoshito Mizuno; 好人水野; Shinya Watabe; 晋也渡部
Original assignee: Tokai Rika Co Ltd
Current assignee: Tokai Rika Co Ltd
Priority date: 2006-06-21
Filing date: 2006-06-21
Publication date: 2008-01-10

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle communication system with a noise radio wave direction detecting and reducing function that can reduce the influence due to noise radio wave, having high intensity as much as possible, when there is a vehicle in an environment where the noise radio wave having high intensity arrives. <P>SOLUTION: The vehicle communication system includes four directional receiving antennas 12a, 12b, 12c, and 12d fitted to the vehicle, a receiving circuit 15 which amplifies and demodulates radio waves received by the respective directional receiving antennas, and an RSSI circuit 16 which converts the intensity of the noise radio wave into noise signal intensity. The noise signal intensity S is compared with a prescribed level SL to determine the magnitudes of the two; and when the noise signal intensity S is larger than the prescribed level SL (when S>SL), the directional receiving antenna having received the noise radio waves is disconnected from the receiving circuit 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、自家用自動車等の車両に設けられ、同車両に備えられた受信機が本来受信すべき有効な電波の受信の妨げとなるノイズ電波（妨害波）の影響を低減する車両通信システムに関し、詳しくは、当該ノイズ電波の影響を低減することで、車両の運転者によって所持される携帯機（送信機）と、同車両に備えられた受信機との間の通信不良を改善するノイズ電波方向検知及び低減機能付き車両通信システムに関する。 The present invention relates to a vehicle communication system that is provided in a vehicle such as a private automobile and that reduces the influence of noise radio waves (interference waves) that interfere with reception of effective radio waves that should be received by a receiver provided in the vehicle. Specifically, the noise radio wave that improves the communication failure between the portable device (transmitter) possessed by the driver of the vehicle and the receiver provided in the vehicle by reducing the influence of the noise radio wave. The present invention relates to a vehicle communication system with a direction detection and reduction function.

近年、自家用自動車等の車両においては、セキュリティレベルの向上を目的として、自動エントリ機能を有する電子キーシステムが提案されている（例えば、特許文献１参照）。ここで、「自動エントリ機能」とは、前記システムに対応する電子キー（携帯機）を所持している車両の運転者が車外の所定領域に進入してきた場合に、車載ドアのアンロック（解錠）を許可したり、エンジンを始動可能な状態としたりする機能をいう。 In recent years, in vehicles such as private automobiles, an electronic key system having an automatic entry function has been proposed for the purpose of improving the security level (see, for example, Patent Document 1). Here, the “automatic entry function” refers to unlocking (unlocking) an in-vehicle door when a vehicle driver who has an electronic key (portable device) corresponding to the system enters a predetermined area outside the vehicle. Lock) or a function to start the engine.

この電子キーには、車両ごとに個別に設定されたＩＤコード（運転者のＩＤコード）が記憶されており、車両に備えられた受信機には、前記電子キーのＩＤコードと同一のＩＤコード（車両の正当使用者のＩＤコード）が記憶されている。ここで、車両からは、常時、電子キーへリクエスト信号が送信されており、このリクエスト信号を電子キーが受信すると、電子キーから運転者のＩＤコードを含む電波が前記受信機に送信される。そして、この受信機にて両ＩＤコードが一致したことが確認されると、ドアロック制御装置やエンジン制御装置に制御信号が送信され、自動エントリ機能が有効となって車載ドアのアンロックが許可されたり、エンジンが始動可能な状態とされたりする。
特開２００５−２００８５４号公報 In this electronic key, an ID code (driver's ID code) set individually for each vehicle is stored, and in the receiver provided in the vehicle, the same ID code as the ID code of the electronic key is stored. (ID code of authorized user of vehicle) is stored. Here, a request signal is constantly transmitted from the vehicle to the electronic key. When the electronic key receives the request signal, a radio wave including the driver's ID code is transmitted from the electronic key to the receiver. When the receiver confirms that both ID codes match, a control signal is transmitted to the door lock control device and engine control device, and the automatic entry function is enabled to allow the vehicle door to be unlocked. Or the engine can be started.
Japanese Patent Laying-Open No. 2005-200854

ところで、前記した電子キーシステムにおいては、電子キーからの電波を受信する受信アンテナが備えられ、この受信アンテナには、通常、無指向性のもの（指向性が意図的に管理されていないもの）が用いられている。このような無指向性受信アンテナを車両に設置すると、常時、当該車両を取り囲む全ての方向（３６０°方向）から到来する電波が受信される状態となる。 By the way, the above-described electronic key system is provided with a receiving antenna for receiving radio waves from the electronic key, and this receiving antenna is usually omnidirectional (one whose directivity is not managed intentionally). Is used. When such an omnidirectional receiving antenna is installed in a vehicle, radio waves arriving from all directions (360 ° direction) surrounding the vehicle are always received.

このため、前記車両の近傍にテレビ塔等のノイズ電波源が存在すると、当該ノイズ電波源から発信されたＵＨＦ（Ultra High Frequency：極超短波）帯の指向性の強いノイズ電波が車両の受信機によって受信されるようになる。これにより、ノイズ電波の受信レベルが高い場合に、当該受信機内に備えられた受信回路がそのノイズ電波によって飽和してしまう。この結果、携帯機から送信され、運転者のＩＤコードを含んだ本来受信すべき有効な電波が、その受信感度を高めても受信できなくなる。この結果、車両の正当使用者が車両内に乗車できなくなる場合がある。 For this reason, when a noise radio wave source such as a TV tower is present in the vicinity of the vehicle, a highly directional noise radio wave in the UHF (Ultra High Frequency) band transmitted from the noise radio wave source is received by the vehicle receiver. Will come to be. Thereby, when the reception level of the noise radio wave is high, the reception circuit provided in the receiver is saturated by the noise radio wave. As a result, the effective radio wave that is transmitted from the portable device and that should be received including the driver's ID code cannot be received even if the reception sensitivity is increased. As a result, an authorized user of the vehicle may not be able to get in the vehicle.

本発明は、上記問題点を解決するためになされたものであって、その目的は、高い強度を有するノイズ電波が到来する環境下に車両が存在する場合に、当該ノイズ電波の影響を可能な限り低減し、車両側で受信すべき有効な電波の受信状態を改善するノイズ電波方向検知及び低減機能付き車両通信システムを提供することにある。 The present invention has been made to solve the above-described problems, and its object is to enable the influence of noise radio waves when the vehicle is present in an environment where noise radio waves having high intensity arrive. An object of the present invention is to provide a vehicle communication system with a noise radio wave direction detection and reduction function that reduces as much as possible and improves the reception state of effective radio waves to be received on the vehicle side.

上記問題点を解決するために、請求項１に記載の発明は、車両に取付けられ、前記車両を囲む方向から到来する電波を受信可能とされるとともに、それぞれが互いに異なる特定方向からの電波を選択的に受信するようにされた複数の指向性受信アンテナ手段と、各指向性受信アンテナ手段で受信した電波を増幅及び復調する受信電波復調増幅手段と、各指向性受信アンテナ手段で受信され、さらに前記受信電波復調増幅手段にて増幅及び復調されたノイズ電波の強度をノイズ信号強度に変換するノイズ電波変換手段と、前記ノイズ信号強度と所定レベルとを比較して両者の大小を判定するノイズ信号強度判定手段と、を備えた車両通信システムにおいて、前記ノイズ信号強度が前記所定レベルよりも大きいことが判定された場合に、前記所定レベルよりも大きいノイズ電波を受信した指向性受信アンテナ手段を前記複数の指向性受信アンテナ手段が本来受信すべき有効な電波の受信に使用しないように前記受信電波復調増幅手段から切離すアンテナ切離手段をさらに備え、前記複数の指向性受信アンテナ手段によって前記所定レベルよりも大きいノイズ電波を受信した場合には、前記アンテナ切離手段によって前記所定レベルよりも大きいノイズ電波を受信した指向性受信アンテナ手段を前記受信電波復調増幅手段から切離すとともに、前記複数の指向性受信アンテナ手段の内、前記所定レベルを超えたノイズ電波を受信した指向性受信アンテナ手段以外の指向性受信アンテナ手段を前記有効な電波の受信に使用するように構成したこと、を要旨とする。 In order to solve the above problem, the invention according to claim 1 is attached to a vehicle and is capable of receiving radio waves coming from directions surrounding the vehicle, and receiving radio waves from different specific directions. A plurality of directional receiving antenna means adapted to selectively receive, a received radio wave demodulation amplifying means for amplifying and demodulating radio waves received by each directional receiving antenna means, and received by each directional receiving antenna means, Further, noise radio wave converting means for converting the intensity of the noise radio wave amplified and demodulated by the received radio wave demodulation amplifying means into noise signal intensity, and noise for comparing the noise signal intensity with a predetermined level to determine the magnitude of both And a signal strength determination unit, wherein the predetermined signal level is determined when it is determined that the noise signal strength is greater than the predetermined level. Antenna separation that separates the directional receiving antenna means that has received a noise radio wave larger than the bell from the received radio wave demodulating and amplifying means so that the plurality of directional receiving antenna means are not used for receiving effective radio waves that should be received originally. And a directional receiving antenna that receives a noise radio wave larger than the predetermined level by the antenna separating means when the plurality of directional reception antenna means receive a noise radio wave larger than the predetermined level. And the directional receiving antenna means other than the directional receiving antenna means that has received the noise radio wave exceeding the predetermined level among the plurality of directional receiving antenna means. The gist is that it is configured to be used for reception of various radio waves.

上記請求項１の構成によれば、所定レベルを超えたノイズ信号強度を有するノイズ電波が特定の指向性受信アンテナ手段で受信された場合に、当該特定の指向性受信アンテナ手段が、車両側で本来受信すべき有効な電波の受信に使用されないように受信電波復調増幅手段から切離されるとともに、複数の指向性受信アンテナ手段の内、前記特定の指向性受信アンテナ手段以外の指向性受信アンテナ手段が、本来受信すべき有効な電波の受信に使用されるようになる。これにより、ノイズ電波方向検知及び低減機能付き車両通信システム（を搭載した車両）が、高い強度を有するノイズ電波が到来する環境下に存在する場合に、そのノイズ電波によって受信電波復調増幅手段が飽和する現象が効果的に回避されるとともに、複数の指向性受信アンテナ手段によって受信されるノイズ電波の受信レベルが全体として低減し、車両側での有効な電波の受信感度が高められるようになる。その結果、例えば、このノイズ電波方向検知及び低減機能付き車両通信システムによって電子キーシステムが構成される場合においては、車両の運転者に所持される携帯機から送信され、本来受信すべきＩＤコードを含んだ有効な電波の受信状態が改善され、当該運転者（車両の正当使用者）が車両内に確実に乗車できるようになる。 According to the configuration of the first aspect, when a noise radio wave having a noise signal intensity exceeding a predetermined level is received by the specific directional reception antenna means, the specific directional reception antenna means is The directional receiving antenna means other than the specific directional receiving antenna means among the plurality of directional receiving antenna means is separated from the receiving radio wave demodulation amplifying means so as not to be used for receiving an effective radio wave to be originally received. However, it will be used to receive effective radio waves that should be received. As a result, when a vehicle communication system with a noise radio wave direction detection and reduction function is installed in an environment where a high intensity noise radio wave arrives, the received radio wave demodulation amplification means is saturated by the noise radio wave. This phenomenon is effectively avoided, and the reception level of noise radio waves received by a plurality of directional receiving antenna means is reduced as a whole, and the effective radio wave reception sensitivity on the vehicle side is increased. As a result, for example, in the case where an electronic key system is configured by this vehicle communication system with noise radio wave direction detection and reduction function, the ID code transmitted from the portable device possessed by the driver of the vehicle and originally received is The reception state of the included effective radio wave is improved, and the driver (the authorized user of the vehicle) can surely get in the vehicle.

請求項２に記載の発明は、請求項１に記載の車両通信システムにおいて、前記所定レベルが、前記指向性受信アンテナ手段によって受信されるノイズ電波によって受信電波復調増幅手段が飽和しない当該ノイズ電波の信号レベルの範囲で、最大の信号レベルに設定されていること、を要旨とする。 According to a second aspect of the present invention, in the vehicle communication system according to the first aspect, the predetermined level of the noise radio wave is not saturated by the received radio wave demodulating and amplifying means due to the noise radio wave received by the directional receiving antenna means. The gist is that the maximum signal level is set within the signal level range.

上記請求項２の構成によれば、受信電波復調増幅手段で受信されるノイズ電波の受信レベルが、当該受信電波復調増幅手段を飽和させない最大の信号レベル以下となるので、ノイズ電波によって受信電波復調増幅手段が飽和する現象をより効果的に回避できる。 According to the second aspect of the present invention, the reception level of the noise radio wave received by the received radio wave demodulating and amplifying means is equal to or lower than the maximum signal level that does not saturate the received radio wave demodulating and amplifying means. The phenomenon that the amplification means is saturated can be avoided more effectively.

請求項３に記載の発明は、請求項１又は請求項２に記載の車両通信システムにおいて、前記アンテナ切離手段が、各指向性受信アンテナ手段と前記受信電波復調増幅手段との接続及び切断を行うアンテナ切換回路であり、且つ当該アンテナ切換回路を用いて指向性受信アンテナ手段を一定時間ごとに切り換えて電波を受信するように構成したこと、を要旨とする。 According to a third aspect of the present invention, in the vehicle communication system according to the first or second aspect, the antenna disconnecting means connects and disconnects each directional receiving antenna means and the received radio wave demodulation amplifying means. The gist of the present invention is that the antenna switching circuit is configured to be configured to receive the radio wave by switching the directional receiving antenna means at regular intervals using the antenna switching circuit.

上記請求項３の構成によれば、所定レベルを超えたノイズ信号強度を有するノイズ電波が特定の指向性受信アンテナ手段で受信された場合に、当該特定の指向性受信アンテナ手段が、本来受信すべき有効な電波の受信に使用されないようにアンテナ切換回路によって受信電波復調増幅手段から簡単且つ確実に切離されるようになる。しかも、当該アンテナ切換回路を用いて指向性受信アンテナ手段を一定時間ごとに切り換えて電波を受信するように構成しているので、複数の指向性受信アンテナ手段を所定の時刻で同時に受信に用いる場合に起こる反射波の悪影響を効果的に低減でき、これにより、有効な電波を受信する場合には、複数の指向性受信アンテナ手段の受信感度が全体として高められる。一方、ノイズ電波を受信する場合には、各指向性受信アンテナ手段が、それぞれ個別に受信電波復調増幅手段を介してノイズ電波変換手段に接続される（各指向性受信アンテナ手段から、それぞれ個別に受信電波復調増幅手段を介してノイズ電波変換手段に電波信号が送信される）ので、各指向性受信アンテナ手段ごとのノイズ信号強度と所定レベルとの大小の判定が、より確実に行えるようになる。この結果、ノイズ信号強度が所定レベルよりも大きいノイズ電波を受信した指向性受信アンテナ手段をより正確且つ確実に特定することができるようになる。 According to the configuration of claim 3, when a noise radio wave having a noise signal intensity exceeding a predetermined level is received by the specific directional reception antenna means, the specific directional reception antenna means originally receives the noise radio wave. The antenna switching circuit can be easily and reliably disconnected from the received radio wave demodulating and amplifying means so as not to be used for receiving the effective radio wave. In addition, since the antenna switching circuit is used to switch the directional receiving antenna means at regular intervals to receive radio waves, a plurality of directional receiving antenna means are used for reception at a predetermined time at the same time. Can effectively reduce the adverse effect of the reflected wave, and when receiving an effective radio wave, the reception sensitivity of the plurality of directional receiving antenna means as a whole is enhanced. On the other hand, when receiving a noise radio wave, each directional receiving antenna means is individually connected to the noise radio wave converting means via the received radio wave demodulation amplifying means (from each directional receiving antenna means individually. The radio wave signal is transmitted to the noise radio wave converting means via the reception radio wave demodulating and amplifying means), so that it is possible to more reliably determine the magnitude of the noise signal intensity and the predetermined level for each directional receiving antenna means. . As a result, it becomes possible to more accurately and reliably identify the directional receiving antenna means that has received a noise radio wave having a noise signal intensity greater than a predetermined level.

請求項４に記載の発明は、請求項１〜請求項３のいずれか一項に記載の車両通信システムにおいて、前記各指向性受信アンテナ手段で受信されるノイズ電波が、ＵＨＦ帯に属するものであること（前記各指向性受信アンテナ手段が、ＵＨＦ帯の電波に属するノイズ電波を受信するようにされていること）、を要旨とする。 According to a fourth aspect of the present invention, in the vehicle communication system according to any one of the first to third aspects, the noise radio wave received by each of the directional receiving antenna means belongs to the UHF band. The main point is that each directional receiving antenna means receives a noise radio wave belonging to a radio wave in the UHF band.

上記請求項４の構成によれば、各指向性受信アンテナ手段で受信されるノイズ電波が、ＵＨＦ帯に属するようにされているので、指向性が強く、テレビ塔等の身近なノイズ電波源から頻繁に発せられ、しかも、車両側で本来受信すべき有効な電波がＵＨＦ帯の電波である場合に、特に強力な妨害電波となるＵＨＦ帯のノイズ電波の影響を効果的に排除できるようになる。 According to the configuration of claim 4, since the noise radio waves received by each directional receiving antenna means are made to belong to the UHF band, the directivity is strong, and it is frequently generated from a familiar noise radio wave source such as a TV tower. In addition, when the effective radio wave to be received on the vehicle side is a UHF band radio wave, it is possible to effectively eliminate the influence of the UHF band noise radio wave, which is a particularly strong jamming radio wave.

請求項５に記載の発明は、請求項１〜請求項４のいずれか一項に記載の車両通信システムにおいて、前記車両の運転者を識別する第１のＩＤコードと、前記車両の正当使用者を識別する第２のＩＤコードとを照合する運転者ＩＤコード照合手段と、前記運転者に所持され、所定の電波を送信する携帯機と、をさらに備え、前記有効な電波が、前記携帯機から送信される所定の電波であって、且つ前記第１のＩＤコードを含み、しかも、該第１のＩＤコードが前記有効な電波を介して前記運転者ＩＤコード照合手段に送信されて当該第１のＩＤコードが前記第２のＩＤコードと照合され、両ＩＤコードが一致したことが確認されると前記車両のドアが解錠状態となるように構成したこと、を要旨とする。 According to a fifth aspect of the present invention, in the vehicle communication system according to any one of the first to fourth aspects, a first ID code for identifying a driver of the vehicle and an authorized user of the vehicle Further comprising: a driver ID code collating means for collating with a second ID code for identifying the mobile phone; and a portable device that is carried by the driver and that transmits a predetermined radio wave. And includes the first ID code, and the first ID code is transmitted to the driver ID code collating means via the effective radio wave. The gist of the invention is that the vehicle door is unlocked when one ID code is collated with the second ID code and it is confirmed that the two ID codes match.

上記請求項５の構成によれば、車両の運転者を識別する第１のＩＤコードが車両側で本来受信すべき有効な電波に含まれ、車両の正当使用者を識別する第２のＩＤコードと照合することで車両のドアが解錠可能となる。その結果、例えば、このノイズ電波方向検知及び低減機能付き車両通信システムによって電子キーシステムが構成される場合において、セキュリティー性を高めつつ、車両の正当使用者を確実に車両に乗車可能とすることができる。 According to the fifth aspect of the present invention, the first ID code for identifying the driver of the vehicle is included in the effective radio wave to be received on the vehicle side, and the second ID code for identifying the authorized user of the vehicle. Can be unlocked. As a result, for example, when an electronic key system is configured by a vehicle communication system with noise noise direction detection and reduction function, it is possible to ensure that a legitimate user of the vehicle can get on the vehicle while improving security. it can.

本発明によれば、高い強度を有するノイズ電波が到来する環境下に車両が存在する場合に、当該ノイズ電波の影響を可能な限り低減し、車両側で受信すべき有効な電波の受信状態を改善する車両通信システムが提供できるようになる。 According to the present invention, when a vehicle exists in an environment where high-intensity noise radio waves arrive, the influence of the noise radio waves is reduced as much as possible, and an effective radio wave reception state to be received on the vehicle side is reduced. An improved vehicle communication system can be provided.

以下、本発明を具体化した実施形態について図面に従って説明する。図１（ａ）に示すように、本実施形態のノイズ電波方向検知及び低減機能付き車両通信システム（以下、単に「車両通信システム」という。）は、自家用自動車２（以下、単に「車両２」という。）に取付けられ、それぞれが互いに異なる特定方向からの電波を選択的に受信するようにされた複数の指向性受信アンテナ（Ａ）１２ａ，（Ｂ）１２ｂ，（Ｃ）１２ｃ，（Ｄ）１２ｄ（以下、これらを纏めて「アンテナ要素１２」という。）を備えている。そして、該アンテナ要素１２によって、この車両２を囲む方向（全方向；３６０°方向）から到来する電波を受信可能とされている。尚、本実施形態の車両通信システムは、車両２の運転者に所持され、所定の周波数帯（ＵＨＦ帯）の電波（所定の電波）を送信可能、且つ、所定の周波数帯（ＬＦ［Low Frequency：長波］帯）の電波を受信可能な携帯機１１を備えている。また、本実施形態の車両通信システムにおいては、前記アンテナ要素１２で受信されるノイズ電波は、ＵＨＦ帯に属するものとされている。 DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. As shown in FIG. 1A, a vehicle communication system (hereinafter simply referred to as “vehicle communication system”) with a noise radio wave direction detection and reduction function according to this embodiment is a private automobile 2 (hereinafter simply referred to as “vehicle 2”). A plurality of directional receiving antennas (A) 12a, (B) 12b, (C) 12c, (D) that are selectively attached to each other and receive radio waves from different specific directions. 12d (hereinafter collectively referred to as “antenna element 12”). The antenna element 12 can receive radio waves coming from the direction surrounding the vehicle 2 (omnidirectional; 360 ° direction). The vehicle communication system of the present embodiment is possessed by the driver of the vehicle 2, can transmit radio waves (predetermined radio waves) in a predetermined frequency band (UHF band), and is capable of transmitting a predetermined frequency band (LF [Low Frequency]. : Long wave] band) is provided. Moreover, in the vehicle communication system of this embodiment, the noise radio wave received by the antenna element 12 is assumed to belong to the UHF band.

図１（ａ）に示す車両通信システムにおいては、前記アンテナ要素１２は、車両２の後方のトランク部２ａに設置され、前記携帯機１１は、車両２の右側前方に位置した状態とされている。また、アンテナ要素１２の内、指向性受信アンテナ（Ａ）１２ａは、車両２の右側前方を向くように設けられ、車両２に右側前方から向かって接近する携帯機１１からの電波を選択的に受信できるようにされている。また、指向性受信アンテナ（Ｂ）１２ｂは、車両２の左側前方を向くように設けられ、車両２に右側前方から向かって接近する携帯機１１からの電波を選択的に受信できるようにされている。また、指向性受信アンテナ（Ｃ）１２ｃ及び指向性受信アンテナ（Ｄ）１２ｄは、それぞれ車両２の左側及び右側後方を向くように設けられ、各方向から車両２に向かって接近する携帯機１１からの電波を選択的に受信できるようにされている。尚、図１（ａ）では、ノイズ電波源であるテレビ塔３００からＵＨＦ帯のノイズ電波が車両２に対して発信されている。 In the vehicle communication system shown in FIG. 1 (a), the antenna element 12 is installed in the trunk portion 2 a behind the vehicle 2, and the portable device 11 is positioned in front of the right side of the vehicle 2. . Of the antenna elements 12, the directional receiving antenna (A) 12 a is provided so as to face the front right side of the vehicle 2, and selectively receives radio waves from the portable device 11 approaching the vehicle 2 from the front right side. It can be received. The directional receiving antenna (B) 12b is provided so as to face the left front of the vehicle 2, and can selectively receive radio waves from the portable device 11 approaching the vehicle 2 from the right front. Yes. Further, the directional receiving antenna (C) 12c and the directional receiving antenna (D) 12d are provided so as to face the left side and the right rear side of the vehicle 2, respectively, from the portable device 11 approaching the vehicle 2 from each direction. Can be selectively received. In FIG. 1A, noise radio waves in the UHF band are transmitted to the vehicle 2 from the TV tower 300 that is a noise radio wave source.

本実施形態の車両通信システムは、図１（ｂ）に示すように、前記アンテナ要素１２で受信された電波を受信可能なように当該アンテナ要素１２に電気的に接続された受信機１３をさらに備えている。 As shown in FIG. 1B, the vehicle communication system of the present embodiment further includes a receiver 13 that is electrically connected to the antenna element 12 so as to be able to receive radio waves received by the antenna element 12. I have.

この受信機１３は、車両２に備えられており、図１（ｂ）に示すように、アンテナ要素１２の指向性受信アンテナ１２ａ〜１２ｄを所定のロジックに従って切り換えるアンテナ切換回路１４と、該アンテナ切換回路１４を介してアンテナ要素１２から電波を受信し、その電波を復調して電波信号とし、この電波信号を増幅する受信回路１５とを備えている。該受信機１３は、さらに前記受信回路１５で増幅及び復調された電波信号の強度を受信信号強度（受信した信号の強度を表示する信号）に変換するＲＳＳＩ（Received Signal Strength Indicator：受信信号強度表示）回路１６を備えている。詳述すると、前記アンテナ切換回路１４は、４つのスイッチ（ＳＷａ，ＳＷｂ，ＳＷｃ，ＳＷｄ）を備えている。そして、その内のＳＷａは、前記指向性受信アンテナ（Ａ）１２ａと受信回路１５との電気的接続の切断（開放）に用いられ、その他のスイッチ（ＳＷｂ，ＳＷｃ，ＳＷｄ）は、それぞれ指向性受信アンテナ（Ｂ）１２ｂ，指向性受信アンテナ（Ｃ）１２ｃ，又は指向性受信アンテナ（Ｄ）１２ｄと、受信回路１５との電気的接続の切断に用いられる。また、前記受信回路１５は、電波信号からノイズ電波の信号成分を除去するフィルタ回路１５ａ、ノイズ電波成分除去後の電波信号を増幅する増幅回路１５ｂ、及び電波を復調して電波信号とする復調回路１５ｃを備えている。また、ＲＳＳＩ回路１６は、増幅及び復調後の電波信号についてその受信信号強度を検出可能なように前記受信回路１５内の復調回路１５ｃの出力側に直接、電気的に接続されている。前記アンテナ要素１２によってノイズ電波が受信される場合には、当該ノイズ電波は、アンテナ切換回路１４を経て受信回路１５で電波信号に増幅及び復調され、さらに、当該ノイズ電波の強度は、ＲＳＳＩ回路１６によってノイズ信号強度Ｓ（受信信号強度）に変換される。尚、本実施形態では、アンテナ要素１２及び受信回路１５は、主としてＵＨＦ帯に属する電波を受信するように構成されている。 The receiver 13 is provided in the vehicle 2 and, as shown in FIG. 1B, an antenna switching circuit 14 that switches the directional receiving antennas 12a to 12d of the antenna element 12 according to a predetermined logic, and the antenna switching. A receiving circuit 15 is provided that receives radio waves from the antenna element 12 via the circuit 14, demodulates the radio waves into radio signals, and amplifies the radio signals. The receiver 13 further receives the received signal strength indicator (RSSI) for converting the strength of the radio signal amplified and demodulated by the receiving circuit 15 into a received signal strength (a signal indicating the strength of the received signal). ) Circuit 16 is provided. More specifically, the antenna switching circuit 14 includes four switches (SWa, SWb, SWc, SWd). SWa is used for disconnecting (opening) the electrical connection between the directional receiving antenna (A) 12a and the receiving circuit 15, and the other switches (SWb, SWc, SWd) are respectively directional. It is used for disconnecting the electrical connection between the receiving circuit 15 and the receiving antenna (B) 12b, the directional receiving antenna (C) 12c, or the directional receiving antenna (D) 12d. The receiving circuit 15 includes a filter circuit 15a that removes a signal component of a noise radio wave from a radio wave signal, an amplifier circuit 15b that amplifies the radio signal after the removal of the noise radio wave component, and a demodulation circuit that demodulates the radio wave into a radio signal. 15c. The RSSI circuit 16 is electrically connected directly to the output side of the demodulation circuit 15c in the receiving circuit 15 so that the received signal intensity of the amplified and demodulated radio wave signal can be detected. When a noise radio wave is received by the antenna element 12, the noise radio wave is amplified and demodulated into a radio signal by the receiving circuit 15 via the antenna switching circuit 14, and the intensity of the noise radio wave is determined by the RSSI circuit 16. Is converted into noise signal strength S (reception signal strength). In the present embodiment, the antenna element 12 and the receiving circuit 15 are configured to mainly receive radio waves belonging to the UHF band.

前記受信機１３には、さらに、受信回路１５で増幅及び復調された電波信号と、当該電波信号がＲＳＳＩ回路１６によって変換（検出）された受信信号強度とが入力されるとともに、該入力された電波信号及び受信信号強度について所定の処理を行うマイコン１７が備えられている。該マイコン１７には、図１（ｂ）に示すように、受信回路１５内の復調回路１５ｃの出力側及びＲＳＳＩ回路１６の出力側がそれぞれ個別に電気的に接続されている。さらに、このマイコン１７の一の出力部は、前記アンテナ切換回路１４に電気的に接続されている。そして、当該マイコン１７により行われる制御によって、アンテナ切換回路１４に備えられた４つのスイッチ（ＳＷａ，ＳＷｂ，ＳＷｃ，ＳＷｄ）が所定のロジックに従って切り換えられ、各指向性受信アンテナ１２ａ〜１２ｄと受信回路１５との接続（電気的接続）と切断（開放）とが自在に行われるようになっている。 The receiver 13 is further supplied with the radio signal amplified and demodulated by the receiving circuit 15 and the received signal strength obtained by converting (detecting) the radio signal by the RSSI circuit 16. A microcomputer 17 that performs predetermined processing on the radio signal and the received signal intensity is provided. As shown in FIG. 1B, the microcomputer 17 is electrically connected to the output side of the demodulation circuit 15c in the receiving circuit 15 and the output side of the RSSI circuit 16, respectively. Further, one output section of the microcomputer 17 is electrically connected to the antenna switching circuit 14. Then, by the control performed by the microcomputer 17, the four switches (SWa, SWb, SWc, SWd) provided in the antenna switching circuit 14 are switched according to a predetermined logic, and the directional receiving antennas 12a to 12d and the receiving circuit are switched. Connection (electrical connection) with 15 and disconnection (opening) can be performed freely.

前記マイコン１７には、図１（ｂ）を参照して、前記した所定の処理を行うためのプログラムが記憶されたメモリ１７ａが備えられている。詳述すると、このメモリ１７ａには、前述したノイズ信号強度Ｓを、所定レベルＳＬと比較して両者の大小を判定する第１のプログラムが記憶されている。ここで、この所定レベルＳＬは、本実施形態では、前記アンテナ要素１２によって受信され、アンテナ切換回路１４を経て受信回路１５に入力されるノイズ電波によって当該受信回路１５が飽和しない当該ノイズ電波の信号レベルの範囲で、最大となる信号レベルに設定されている。即ち、ノイズ信号強度Ｓが前記所定レベルＳＬを超えれば、当該ノイズ信号強度Ｓを有するノイズ電波の強度が受信回路１５の許容入力範囲を超えるようになり、受信回路１５が飽和する。尚、この第１のプログラムは、このような電波の信号レベルの大小の判定だけでなく、当該判定結果に基づき、アンテナ切換回路１４を所定のロジックに従って切り換え、指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを受信回路１５と接続及び切断する処理も行われるように構成されている。 Referring to FIG. 1B, the microcomputer 17 includes a memory 17a in which a program for performing the predetermined processing is stored. More specifically, the memory 17a stores a first program for comparing the noise signal intensity S described above with a predetermined level SL to determine the magnitude of both. Here, in this embodiment, the predetermined level SL is received by the antenna element 12, and the signal of the noise radio wave that does not saturate the reception circuit 15 due to the noise radio wave input to the reception circuit 15 via the antenna switching circuit 14 is obtained. The signal level is set to the maximum in the level range. That is, if the noise signal intensity S exceeds the predetermined level SL, the intensity of the noise radio wave having the noise signal intensity S exceeds the allowable input range of the receiving circuit 15, and the receiving circuit 15 is saturated. The first program not only determines the magnitude of the signal level of the radio wave, but also switches the antenna switching circuit 14 according to a predetermined logic based on the determination result, and directivity receiving antennas 12a, 12b, 12c. Or 12d is connected to and disconnected from the receiving circuit 15.

本実施形態の車両通信システムは、アンテナ要素１２によって受信されたノイズ電波のノイズ信号強度Ｓが所定レベルＳＬよりも大きいことが判定された場合に、当該所定レベルＳＬよりも大きいノイズ信号強度Ｓを有するノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを、車両２に備えられたアンテナ要素１２及び受信機１３が本来受信すべき有効な電波の受信に使用しないように、受信回路１５から切離すように構成されている。詳述すると、前記マイコン１７（及びメモリ１７ａに記憶された第１のプログラム）によって、前記ノイズ信号強度Ｓと所定レベルＳＬとの大小関係が判定され、ノイズ信号強度Ｓが所定レベルＳＬより大きいと判定された場合（Ｓ＞ＳＬの場合）には、さらに当該マイコン１７によって、アンテナ切換回路１４が制御される。そして、アンテナ切換回路１４によって、所定レベルＳＬよりも大きいノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄが、前記した有効な電波の受信に使用しないように受信回路１５から切離される。そして、複数の指向性受信アンテナ１２ａ〜１２ｄの内、前記所定レベルＳＬを超えたノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄ以外の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄが前記有効な電波の受信に使用されるようになる。 When it is determined that the noise signal intensity S of the noise radio wave received by the antenna element 12 is greater than the predetermined level SL, the vehicle communication system according to the present embodiment has a noise signal intensity S greater than the predetermined level SL. The directional receiving antennas 12a, 12b, 12c, or 12d that have received the noise radio waves are received so that the antenna element 12 and the receiver 13 provided in the vehicle 2 are not used for receiving effective radio waves that should be received. It is configured to be disconnected from the circuit 15. More specifically, when the microcomputer 17 (and the first program stored in the memory 17a) determines the magnitude relationship between the noise signal intensity S and the predetermined level SL, and the noise signal intensity S is greater than the predetermined level SL. If determined (S> SL), the microcomputer 17 further controls the antenna switching circuit 14. Then, the directional receiving antennas 12a, 12b, 12c, or 12d that have received a noise radio wave greater than the predetermined level SL by the antenna switching circuit 14 are disconnected from the reception circuit 15 so that they are not used for receiving the effective radio wave. To be released. Then, among the plurality of directional reception antennas 12a to 12d, the directional reception antennas 12a, 12b, 12c other than the directional reception antennas 12a, 12b, 12c, or 12d that have received the noise radio wave exceeding the predetermined level SL, Alternatively, 12d is used for receiving the effective radio wave.

本実施形態の車両通信システムは、以上のように構成され、以下に、該車両通信システムの基本動作をフローチャート図に従って説明する。尚、このフローチャートは、マイコン１７内のメモリ１７ａに記憶された前記第１のプログラムの動作フローを示したものである。 The vehicle communication system according to the present embodiment is configured as described above, and the basic operation of the vehicle communication system will be described below with reference to flowcharts. This flowchart shows the operation flow of the first program stored in the memory 17a in the microcomputer 17.

図２に示すように、まず、ステップＳ１において、複数の指向性受信アンテナ（Ａ〜Ｄ）１２ａ〜１２ｄ（以下、図２の説明においては、複数の指向性受信アンテナ（Ａ〜Ｄ）を「ＡＮＴ（Ａ〜Ｄ）」と略記する。）が動作する。次のステップＳ２において、各ＡＮＴのいずれかがノイズ電波源から発せられるノイズ電波を受信したことが認識されると、ステップＳ３に進み、時間変数Ｔ＝０［ｓｅｃ］、時刻変数ｔ＝０［ｓｅｃ］（初期値）にリセットされる。それとともに、続くステップＳ４でＴ＝Ｔ＋α（ここで、α［ｓｅｃ］は「所定の時間サイクル」であり、第１のプログラムに対して任意に設定可能である。）にインクリメントされる。 As shown in FIG. 2, first, in step S1, a plurality of directional receiving antennas (A to D) 12a to 12d (hereinafter, in the description of FIG. ANT (A to D) ") operates. In the next step S2, when it is recognized that any of the ANTs has received the noise radio wave emitted from the noise radio wave source, the process proceeds to step S3, where the time variable T = 0 [sec] and the time variable t = 0 [ sec] (initial value). At the same time, in step S4, T = T + α (where α [sec] is a “predetermined time cycle” and can be arbitrarily set for the first program).

次に、ステップＳ５で、ＡＮＴ（Ａ〜Ｄ）によって受信されたノイズ電波のノイズ信号強度Ｓが、各ＡＮＴごとにＲＳＳＩ回路１６によって検出され、メモリ１７ａに記憶される（各ＡＮＴで受信されたノイズ電波の強度がノイズ信号強度Ｓに変換される）。また、本ステップＳ５において、アンテナ切換回路１４によって、ノイズ電波の受信に使用するＡＮＴ（Ａ〜Ｄ）を一定時間Δｔ［ｓｅｃ］ごとに切り換えて電波を受信するようにする。詳しくは、Ａ，Ｂ，Ｃ，Ｄの順番で電波（ノイズ電波）を受信するＡＮＴをサイクリックに切り換えて行く。 Next, in step S5, the noise signal intensity S of the noise radio wave received by the ANT (AD) is detected by the RSSI circuit 16 for each ANT and stored in the memory 17a (received by each ANT). The intensity of the noise radio wave is converted into the noise signal intensity S). In step S5, the antenna switching circuit 14 switches the ANT (A to D) used for receiving the noise radio wave every predetermined time Δt [sec] to receive the radio wave. Specifically, the ANT that receives radio waves (noise radio waves) is switched cyclically in the order of A, B, C, and D.

続いて、ステップＳ６で、各ＡＮＴにおいて受信されたノイズ電波のノイズ信号強度Ｓが、各ＡＮＴごとに所定レベルＳＬ（この所定レベルＳＬは、前記アンテナ要素１２によって受信され、アンテナ切換回路１４を経て受信回路１５に入力されるノイズ電波によって当該受信回路１５が飽和しない当該ノイズ電波の信号レベルの範囲で、最大となる信号レベルに設定されている。）と比較され、当該所定レベルＳＬを超えた（Ｓ＞ＳＬとなる）ノイズ電波を受信したＡＮＴの存在の有無が判定される。本ステップＳ６では、このようなＳ＞ＳＬとなるＡＮＴが存在しない場合は、ステップＳ１０へ進み、同ステップＳ１０にて時刻変数ｔ［ｓｅｃ］（現在の時刻）が現在の時間変数Ｔ［ｓｅｃ］以上となる（ｔ≧Ｔ）まで待機し、タイムアップ後に前記ステップＳ４に進む。一方、Ｓ＞ＳＬとなるＡＮＴが存在した場合は、次のステップＳ７に進む。 Subsequently, in step S6, the noise signal intensity S of the noise radio wave received at each ANT is a predetermined level SL for each ANT (this predetermined level SL is received by the antenna element 12 and passes through the antenna switching circuit 14). The signal level is set to the maximum within the range of the signal level of the noise radio wave that does not saturate by the noise radio wave input to the receiver circuit 15), and exceeds the predetermined level SL. It is determined whether or not there is an ANT that has received a noise radio wave (S> SL). In step S6, if there is no such ANT that satisfies S> SL, the process proceeds to step S10, where the time variable t [sec] (current time) is changed to the current time variable T [sec]. It waits until it becomes above (t> = T), and progresses to said step S4 after time-up. On the other hand, if there is an ANT that satisfies S> SL, the process proceeds to the next step S7.

次いで、ステップＳ７で、全てのＡＮＴ（Ａ〜Ｄ）でノイズ信号強度Ｓが所定レベルＳＬを超えている（Ｓ＞ＳＬ）か否かが判定される。本ステップＳ７では、このようなＳ＞ＳＬとなるＡＮＴが存在しない場合は、ステップＳ１０へ進み、同ステップＳ１０にて時刻変数ｔ［ｓｅｃ］（現在の時刻）が現在の時間変数Ｔ［ｓｅｃ］以上となる（ｔ≧Ｔ）まで待機し、タイムアップ後に前記ステップＳ４に進む。一方、全てのＡＮＴでＳ＞ＳＬとならない場合（少なくとも１つのアンテナでＳ≦ＳＬとなり、且つ、少なくとも１つのアンテナでＳ＞ＳＬとなる場合）は、次のステップＳ８に進む。 Next, in step S7, it is determined whether or not the noise signal intensity S exceeds a predetermined level SL in all ANTs (A to D) (S> SL). In step S7, if there is no such ANT that satisfies S> SL, the process proceeds to step S10, where the time variable t [sec] (current time) is changed to the current time variable T [sec]. It waits until it becomes above (t> = T), and progresses to said step S4 after time-up. On the other hand, if S> SL is not satisfied in all ANTs (S ≦ SL with at least one antenna and S> SL with at least one antenna), the process proceeds to the next step S8.

続いて、ステップＳ８で、複数のＡＮＴ（Ａ〜Ｄ）の内、Ｓ＞ＳＬとなるＡＮＴが特定され、さらに、当該特定されたＡＮＴを前記受信機１３内の受信回路１５から切り離すべく、マイコン１７からアンテナ切換回路１４に制御信号が送信され、この特定されたＡＮＴと受信回路１５との電気的接続が切断される（該特定されたＡＮＴと接続されたスイッチ（ＳＷａ，ＳＷｂ，ＳＷｃ，又はＳＷｄ）が開放される。）。尚、この電気的接続の切断に伴い、Ｓ＞ＳＬとなるＡＮＴ以外のＡＮＴ（Ｓ≦ＳＬとなるＡＮＴ）が、携帯機１１から送信される本来受信すべき電波の受信に使用されることになる。 Subsequently, in step S8, among the plurality of ANTs (A to D), an ANT satisfying S> SL is specified, and the microcomputer is further disconnected from the receiving circuit 15 in the receiver 13. The control signal is transmitted from 17 to the antenna switching circuit 14, and the electrical connection between the specified ANT and the receiving circuit 15 is cut off (switches connected to the specified ANT (SWa, SWb, SWc, or SWd) is released.) With the disconnection of the electrical connection, an ANT other than the ANT that satisfies S> SL (ANT that satisfies S ≦ SL) is used for reception of radio waves that should be received from the portable device 11. Become.

最後に、ステップＳ９において、携帯機１１を所持した運転者（車両２の正当使用者）が車両２に乗車したか否かが車両２に備えられた別の検出装置によって検出され、当該運転者がまだ車両２に乗車していない場合は、当該検出装置から制御信号がマイコン１７に送信され、前記ステップＳ１０へ進む。同ステップＳ１０にて時刻変数ｔ［ｓｅｃ］（現在の時刻）が現在の時間変数Ｔ［ｓｅｃ］以上（ｔ≧Ｔ）となるまで待機し、タイムアップ後に前記ステップＳ４に進む。一方、前記運転者が既に車両２に乗車している場合は、前記別の検出装置からマイコン１７に制御信号が送信され、本実施形態の車両通信システムの動作が終了する。 Finally, in step S9, whether or not the driver (authorized user of the vehicle 2) who has the portable device 11 gets on the vehicle 2 is detected by another detection device provided in the vehicle 2, and the driver If the vehicle 2 is not yet on the vehicle 2, a control signal is transmitted from the detection device to the microcomputer 17, and the process proceeds to step S10. In step S10, the process waits until the time variable t [sec] (current time) becomes equal to or greater than the current time variable T [sec] (t ≧ T), and proceeds to step S4 after the time is up. On the other hand, when the driver has already boarded the vehicle 2, a control signal is transmitted from the other detection device to the microcomputer 17, and the operation of the vehicle communication system of the present embodiment ends.

尚、本実施形態の車両通信システムは、背景技術で説明したいわゆる電子キーシステムを構成している。即ち、図１（ｂ）に示すように、前記車両２に備えられた受信機１３内のマイコン１７には、車両２に備えられたドアロック制御装置２ｂ及びエンジン制御装置２ｃとが当該マイコン１７によって制御可能なように電気的に接続されている。また、前記携帯機１１から送信される所定の電波（有効な電波）には、車両２の運転者（携帯機１１の所持者）を識別する第１のＩＤコードが含まれている。そして、当該第１のＩＤコードは、前記所定の電波を介して、前記携帯機１１からマイコン１７に送信されることで、前記第１のＩＤコードが、当該マイコン１７のメモリ１７ａに登録され、車両２の正当使用者を識別する第２のＩＤコードと照合される。そして、両ＩＤコードが一致したことが確認されると、マイコン１７から前記ドアロック制御装置２ｂ及びエンジン制御装置２ｃに制御信号が送信され、車両２のドアが解錠可能な状態となるとともに車両２のエンジンが始動可能な状態となるように構成されている。即ち、本実施形態では、前記マイコン１７内のメモリ１７ａには、前記した第１のプログラムに加え、さらに、前記第１のＩＤコードと第２のＩＤコードの一致・不一致を判定するとともに、当該判定結果に基づきドアロック制御装置２ｂ及びエンジン制御装置２ｃに制御信号を送信する第２のプログラムが記憶されている。 The vehicle communication system of the present embodiment constitutes a so-called electronic key system described in the background art. That is, as shown in FIG. 1B, the microcomputer 17 in the receiver 13 provided in the vehicle 2 includes the door lock control device 2 b and the engine control device 2 c provided in the vehicle 2. It is electrically connected so that it can be controlled by. The predetermined radio wave (effective radio wave) transmitted from the portable device 11 includes a first ID code for identifying the driver of the vehicle 2 (the owner of the portable device 11). Then, the first ID code is transmitted from the portable device 11 to the microcomputer 17 via the predetermined radio wave, whereby the first ID code is registered in the memory 17a of the microcomputer 17, It is collated with the second ID code for identifying the authorized user of the vehicle 2. When it is confirmed that both ID codes match, a control signal is transmitted from the microcomputer 17 to the door lock control device 2b and the engine control device 2c, and the door of the vehicle 2 becomes unlockable and the vehicle It is comprised so that the engine of 2 can be started. That is, in the present embodiment, the memory 17a in the microcomputer 17 determines whether the first ID code and the second ID code match or not, in addition to the first program, A second program for transmitting a control signal to the door lock control device 2b and the engine control device 2c based on the determination result is stored.

本実施形態の車両通信システムによれば、以下のような作用・効果を得ることができる。
（１）本実施形態では、前記所定レベルＳＬを超えたノイズ信号強度Ｓを有するノイズ電波が特定の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄで受信された場合に、当該特定の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄが、本来受信すべき有効な電波の受信に使用されないように受信機１３内の受信回路１５から切離される。それとともに、複数の指向性受信アンテナ１２ａ〜１２ｄの内、前記した特定の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄ以外の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄが、前記有効な電波の受信に使用されるようになる。これにより、本実施形態の車両通信システム（を搭載した車両２）が、高い強度を有するノイズ電波が到来する環境下に存在する場合に、そのノイズ電波によって受信機１３内の受信回路１５が飽和する現象が効果的に回避される。それとともに、アンテナ要素１２によって受信されるノイズ電波の受信レベルが全体として低減し、前記有効な電波の受信感度が高められるようになる。その結果、本実施形態の車両通信システムで構成される電子キーシステムにおいては、車両２の運転者（車両２の正当使用者）に所持される携帯機１１から送信され、車両２側で本来受信すべきＩＤコードを含んだ有効な電波の受信状態が改善され、当該運転者が車両２内に確実に乗車できるようになる。さらに、本実施形態によれば、所定レベルＳＬを超えたノイズ信号強度を有するノイズ電波を受信した特定の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを受信回路１５から切離すという簡便且つ確実な手段で当該指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを前記有効な電波の受信に使用しないようにすることができる。 According to the vehicle communication system of the present embodiment, the following operations and effects can be obtained.
(1) In the present embodiment, when a noise radio wave having a noise signal intensity S exceeding the predetermined level SL is received by a specific directivity receiving antenna 12a, 12b, 12c, or 12d, the specific directivity The receiving antenna 12a, 12b, 12c, or 12d is disconnected from the receiving circuit 15 in the receiver 13 so as not to be used for receiving an effective radio wave that should be received. In addition, among the plurality of directional receiving antennas 12a to 12d, the directional receiving antennas 12a, 12b, 12c, or 12d other than the specific directional receiving antennas 12a, 12b, 12c, or 12d described above are effective. It will be used to receive radio waves. Thereby, when the vehicle communication system (vehicle 2 equipped with this embodiment) is present in an environment where noise waves having high intensity arrive, the reception circuit 15 in the receiver 13 is saturated by the noise waves. This phenomenon is effectively avoided. At the same time, the reception level of the noise radio wave received by the antenna element 12 is reduced as a whole, and the reception sensitivity of the effective radio wave is increased. As a result, in the electronic key system constituted by the vehicle communication system of the present embodiment, the electronic key system is transmitted from the portable device 11 possessed by the driver of the vehicle 2 (the authorized user of the vehicle 2) and originally received on the vehicle 2 side. The reception state of the effective radio wave including the ID code to be improved is improved, and the driver can surely get in the vehicle 2. Furthermore, according to the present embodiment, the specific directional receiving antenna 12a, 12b, 12c, or 12d that has received the noise radio wave having the noise signal intensity exceeding the predetermined level SL is simply and reliably separated from the receiving circuit 15. Thus, the directional receiving antenna 12a, 12b, 12c, or 12d can be prevented from being used for receiving the effective radio wave.

（２）本実施形態では、前記所定レベルＳＬが、複数の指向性受信アンテナ１２ａ〜１２ｄによって受信されるノイズ電波によって受信回路１５が飽和しない当該ノイズ電波の信号レベルの範囲で、最大の信号レベルに設定されている。このため、受信回路１５を飽和させるノイズ信号強度Ｓを有するノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄが、アンテナ切換回路１４によって、受信回路１５から切り離され、受信回路１５で受信されるノイズ電波の受信レベルが、当該受信回路１５を飽和させない最大の信号レベル以下となる。この結果、ノイズ電波によって受信回路１５が飽和する現象を確実に回避することができる。 (2) In the present embodiment, the predetermined level SL is the maximum signal level within the range of the signal level of the noise radio wave that does not saturate the reception circuit 15 due to the noise radio waves received by the plurality of directional receiving antennas 12a to 12d. Is set to Therefore, the directional receiving antenna 12a, 12b, 12c, or 12d that has received the noise radio wave having the noise signal intensity S that saturates the receiving circuit 15 is disconnected from the receiving circuit 15 by the antenna switching circuit 14, and the receiving circuit 15 The reception level of the noise radio wave received at is lower than the maximum signal level that does not saturate the receiving circuit 15. As a result, it is possible to reliably avoid the phenomenon that the receiving circuit 15 is saturated by noise radio waves.

（３）本実施形態では、アンテナ切換回路１４によって、各指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，及び１２ｄを一定時間Δｔ［ｓｅｃ］ごとに切り換えてノイズ電波の受信に使用するように構成されている。このため、複数の指向性受信アンテナ１２ａ〜１２ｄにて所定の時刻で同時に電波を受信する場合に起こる反射波の影響、即ち、受信すべき直接波が地表面で反射されてアンテナ要素１２への入射角度が変更される。これにより、直接波を受信する指向性受信アンテナとは異なる指向性受信アンテナで受信される反射波による影響を効果的に低減でき、前記有効な電波を受信する場合には、アンテナ要素１２の受信感度が全体として高められる。一方、ノイズ電波を受信する場合には、各指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄが、それぞれ個別に受信回路１５を介してＲＳＳＩ回路１６に接続される（各指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄから、それぞれ個別に受信回路１５を介してＲＳＳＩ回路１６に電波信号が送信される）。これにより、各指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄごとのノイズ信号強度Ｓと所定レベルＳＬとの大小の判定が、より確実に行えるようになる。この結果、ノイズ信号強度Ｓが所定レベルＳＬよりも大きいノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを正確且つ確実に特定することができるようになる。 (3) In this embodiment, the directional receiving antennas 12a, 12b, 12c, and 12d are switched by the antenna switching circuit 14 every predetermined time Δt [sec] to be used for receiving noise radio waves. Yes. For this reason, the influence of the reflected wave that occurs when radio waves are simultaneously received at a predetermined time by the plurality of directional receiving antennas 12a to 12d, that is, the direct wave to be received is reflected on the ground surface and is applied to the antenna element 12. The incident angle is changed. Thereby, it is possible to effectively reduce the influence of the reflected wave received by the directional receiving antenna different from the directional receiving antenna that receives the direct wave. When the effective radio wave is received, the reception of the antenna element 12 is possible. Sensitivity is increased as a whole. On the other hand, when receiving a noise radio wave, each directional receiving antenna 12a, 12b, 12c, or 12d is individually connected to the RSSI circuit 16 via the receiving circuit 15 (each directional receiving antenna 12a, 12b, 12c, or 12d individually transmits a radio signal to the RSSI circuit 16 via the receiving circuit 15). This makes it possible to more reliably determine the magnitude of the noise signal intensity S and the predetermined level SL for each directional receiving antenna 12a, 12b, 12c, or 12d. As a result, the directional receiving antennas 12a, 12b, 12c, or 12d that have received noise radio waves having a noise signal intensity S greater than the predetermined level SL can be accurately and reliably specified.

（４）本実施形態では、複数の指向性受信アンテナ１２ａ〜１２ｄが、ＵＨＦ帯の電波に属するノイズ電波を受信するようにされている。このため、指向性が強く、しかも、テレビ塔等の身近なノイズ電波源から頻繁に発せられ、しかも、運転者が所持した携帯機１１から送信され、車両２側で本来受信すべき有効な電波がＵＨＦ帯の電波である場合に、特に強力な妨害電波となるＵＨＦ帯のノイズ電波の影響を効果的に排除できるようになる。 (4) In the present embodiment, the plurality of directional receiving antennas 12a to 12d are configured to receive noise radio waves belonging to UHF band radio waves. For this reason, directivity is strong, and it is frequently emitted from a familiar noise radio wave source such as a TV tower, and the effective radio wave that is transmitted from the portable device 11 possessed by the driver and should be originally received on the vehicle 2 side is generated. In the case of UHF band radio waves, it is possible to effectively eliminate the influence of UHF band noise radio waves, which are particularly powerful jamming radio waves.

（５）本実施形態では、車両２の運転者を識別する第１のＩＤコードが車両２側で本来受信すべき有効な電波に含まれ、車両２の正当使用者を識別する第２のＩＤコードと照合することで車両２のドアが解錠可能及び車両２のエンジンが始動可能となる。その結果、本実施形態の車両通信システムで構成される電子キーシステムにおいては、セキュリティー性を高めつつ、車両の正当使用者を確実に車両に乗車可能且つエンジン始動可能とすることができる。 (5) In the present embodiment, the first ID code for identifying the driver of the vehicle 2 is included in the effective radio wave to be originally received on the vehicle 2 side, and the second ID for identifying the authorized user of the vehicle 2 By collating with the code, the door of the vehicle 2 can be unlocked and the engine of the vehicle 2 can be started. As a result, in the electronic key system configured by the vehicle communication system of the present embodiment, it is possible to make it possible for a legitimate user of the vehicle to surely get on the vehicle and to start the engine while improving security.

尚、上記実施形態は以下のように変形してもよい。
・上記実施形態では、所定レベルＳＬを超えたノイズ信号強度Ｓを有するノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄ以外の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを、本来受信すべき有効な電波の受信に使用するために、当該ノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを受信回路１５から切離す手段を用いた。しかし、この手段に代えて、当該ノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄが本来受信すべき有効な電波の受信に実質的に使用されないようにその受信感度を前記ノイズ電波を受信していない指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄに比して相対的に低下させる手段（アンテナ受信感度低下手段）を用いてもよい。これによっても、上記実施形態と同等の効果が得られる。 The above embodiment may be modified as follows.
In the above embodiment, the directional receiving antennas 12a, 12b, 12c, or 12d other than the directional receiving antennas 12a, 12b, 12c, or 12d that have received the noise radio wave having the noise signal intensity S exceeding the predetermined level SL are used. In order to use it for receiving an effective radio wave that should be received, means for separating the directional receiving antennas 12a, 12b, 12c, or 12d that received the noise radio wave from the receiving circuit 15 was used. However, instead of this means, the directional reception antenna 12a, 12b, 12c, or 12d that has received the noise radio wave has its reception sensitivity reduced so that it is not substantially used for receiving an effective radio wave that should be received. Means (antenna reception sensitivity lowering means) for lowering relative to the directional receiving antennas 12a, 12b, 12c, or 12d that are not receiving radio waves may be used. This also provides the same effect as the above embodiment.

・上記実施形態では、所定レベルＳＬを超えたノイズ信号強度Ｓを有するノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄ以外の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを、本来受信すべき有効な電波の受信に使用するために、当該ノイズ電波を受信した指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄを受信回路１５から切離すように構成した。しかし、これに代えて、ノイズ信号強度Ｓが所定レベルＳＬ以下であって、且つアンテナ要素１２内でノイズ信号強度Ｓが最小となる一の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄのみを、本来受信すべき有効な電波の受信に使用するように構成することも可能である。これにより、一の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄによって反射波の影響を排除しつつ、しかも、ノイズ電波の影響を低減しながら、前記有効な電波を可能な限り感度を高めて受信することができる。さらに、この場合は、全ての指向性受信アンテナ１２ａ〜１２ｄにおいて、ノイズ信号強度Ｓが所定レベルＳＬを超えないときでも、前記一の指向性受信アンテナ１２ａ，１２ｂ，１２ｃ，又は１２ｄによって、前記有効な電波を感度良く受信することが可能となる。 In the above embodiment, the directional receiving antennas 12a, 12b, 12c, or 12d other than the directional receiving antennas 12a, 12b, 12c, or 12d that have received the noise radio wave having the noise signal intensity S exceeding the predetermined level SL are used. The directivity receiving antennas 12a, 12b, 12c, or 12d that have received the noise radio wave are separated from the receiving circuit 15 in order to receive effective radio waves that should be received. However, instead of this, only one directional receiving antenna 12a, 12b, 12c, or 12d in which the noise signal strength S is equal to or lower than the predetermined level SL and the noise signal strength S is minimum in the antenna element 12 is used. It is also possible to configure to use for receiving an effective radio wave that should be received. Thus, the sensitivity of the effective radio wave is increased as much as possible while eliminating the influence of the reflected wave by the one directional receiving antenna 12a, 12b, 12c, or 12d and reducing the influence of the noise radio wave. Can be received. Furthermore, in this case, even when the noise signal intensity S does not exceed the predetermined level SL in all the directional receiving antennas 12a to 12d, the effective signal is transmitted by the one directional receiving antenna 12a, 12b, 12c, or 12d. It is possible to receive various radio waves with high sensitivity.

・上記実施形態では、所定レベルＳＬを、各指向性受信アンテナ１２ａ〜１２ｄによって受信されるノイズ電波によって受信回路１５が飽和しない当該ノイズ電波の信号レベルの範囲で、最大の信号レベルに設定した。しかし、これに限られず、例えば、当該最大の信号レベルの０．８倍や０．９倍等、０を超えて１．０以下の所定の定数倍に設定することもできる。さらに、前記した実施形態および変形例より把握できる技術的思想について以下に記載する。 In the above embodiment, the predetermined level SL is set to the maximum signal level within the range of the signal level of the noise radio wave that does not saturate the reception circuit 15 by the noise radio wave received by each of the directional receiving antennas 12a to 12d. However, the present invention is not limited to this. For example, the maximum signal level can be set to a predetermined constant multiple of 0 and 1.0 or less, such as 0.8 times or 0.9 times. Further, technical ideas that can be grasped from the above-described embodiments and modifications will be described below.

・請求項１〜請求項５のいずれか一項に記載の車両通信システムにおいて、前記ノイズ信号強度を前記複数の指向性受信アンテナ手段間で比較し、当該ノイズ信号強度が最小となるノイズ電波を受信した指向性受信アンテナ手段を特定するアンテナ特定手段をさらに備え、当該特定された一の指向性受信アンテナ手段を前記有効な電波の受信に使用するように構成したノイズ電波方向検知及び低減機能付き車両通信システム。この構成によれば、一の指向性受信アンテナ手段によって反射波の影響を排除しつつ、しかも、ノイズ電波の影響を低減しながら、本来受信すべき有効な電波を可能な限り感度を高めて受信することができる。さらに、この場合は、全ての指向性受信アンテナ手段において、ノイズ信号強度が所定レベルを超えないときでも、前記有効な電波を感度良く受信することが可能となる。 In the vehicle communication system according to any one of claims 1 to 5, the noise signal intensity is compared between the plurality of directional receiving antenna means, and a noise radio wave that minimizes the noise signal intensity is obtained. With a noise radio wave direction detection and reduction function further comprising an antenna specifying means for specifying the received directional receiving antenna means, and using the specified one directional receiving antenna means for receiving the effective radio wave Vehicle communication system. According to this configuration, while receiving the influence of the reflected wave by one directional receiving antenna means and reducing the influence of the noise radio wave, the effective radio wave to be received is received with the highest possible sensitivity. can do. Further, in this case, the effective radio wave can be received with high sensitivity even when the noise signal intensity does not exceed a predetermined level in all the directional receiving antenna means.

・請求項１〜請求項５のいずれか一項に記載の車両通信システムにおいて、前記ノイズ信号強度が前記所定レベルよりも大きいことが判定された場合に、前記所定レベルよりも大きいノイズ電波を受信した指向性受信アンテナ手段を前記複数の指向性受信アンテナ手段が本来受信すべき有効な電波の受信に使用しないように前記受信電波復調増幅手段から切離すアンテナ切離手段に代えて、前記ノイズ信号強度判定手段によって前記ノイズ信号強度が前記所定レベルよりも大きいことが判定された場合に、当該ノイズ電波を受信した指向性受信アンテナ手段を前記複数の指向性受信アンテナ手段を本来受信すべき有効な電波の受信に使用しないように当該ノイズ電波を受信した指向性受信アンテナ手段の受信感度を前記ノイズ電波を受信していない指向性受信アンテナ手段に比して相対的に低下させるアンテナ受信感度低下手段を備え、前記複数の指向性受信アンテナ手段によって前記所定レベルよりも大きいノイズ電波を受信した場合には、前記アンテナ受信感度低下手段によって前記所定レベルよりも大きいノイズ電波を受信した指向性受信アンテナ手段の受信感度を前記ノイズ電波を受信していない指向性受信アンテナ手段に比して相対的に低下させるとともに、前記複数の指向性受信アンテナ手段の内、前記所定レベルを超えたノイズ電波を受信した指向性受信アンテナ手段以外の指向性受信アンテナ手段を前記有効な電波の受信に実質的に使用するように構成したことを特徴とするノイズ電波方向検知及び低減機能付き車両通信システム。このアンテナ受信感度低下手段を備える構成によれば、前記ノイズ信号強度判定手段を備えた構成（請求項１の構成）と同等の作用効果が得られる。尚、この場合、アンテナ受信感度低下手段は、車両に備えられた受信機（指向性受信アンテナ手段から送信される電波の強度を低減させるアッテネータ手段（請求項１のアンテナ切離手段に代えて配置される。）及び該アッテネータ手段を制御するマイコンを含む）で構成することができる。また、この場合、所定レベルは、ノイズ電波によって受信電波復調増幅手段が飽和しない当該ノイズ電波の信号レベルの範囲での最大の信号レベルよりも低いレベルに設定することが好ましい。 In the vehicle communication system according to any one of claims 1 to 5, when it is determined that the noise signal intensity is greater than the predetermined level, a noise radio wave greater than the predetermined level is received. In place of the antenna separating means for separating the received directional receiving antenna means from the received radio wave demodulating and amplifying means so that the plurality of directional receiving antenna means are not used for receiving effective radio waves to be originally received, the noise signal When it is determined by the intensity determining means that the noise signal intensity is greater than the predetermined level, the directional receiving antenna means that has received the noise radio wave is effectively received by the plurality of directional receiving antenna means. The reception sensitivity of the directional receiving antenna means that has received the noise radio wave is not used for receiving the radio wave. Antenna receiving sensitivity lowering means for lowering relative to non-directive receiving antenna means, and when receiving the noise radio wave larger than the predetermined level by the plurality of directional receiving antenna means, the antenna receiving Receiving sensitivity of the directional receiving antenna means that has received a noise radio wave greater than the predetermined level by the sensitivity reducing means is relatively reduced as compared to the directional receiving antenna means that has not received the noise radio wave, The directivity receiving antenna means other than the directivity receiving antenna means that has received the noise radio wave exceeding the predetermined level is substantially used for receiving the effective radio wave. A vehicle communication system with noise radio wave direction detection and reduction function. According to the configuration including the antenna reception sensitivity lowering unit, the same operational effects as the configuration including the noise signal intensity determination unit (the configuration of claim 1) can be obtained. In this case, the antenna reception sensitivity lowering means is a receiver provided in the vehicle (attenuator means for reducing the intensity of the radio wave transmitted from the directional receiving antenna means (arranged in place of the antenna separation means of claim 1). And a microcomputer for controlling the attenuator means). In this case, the predetermined level is preferably set to a level lower than the maximum signal level in the range of the signal level of the noise radio wave that does not saturate the received radio wave demodulating and amplifying means.

本発明の実施形態に係る車両通信システムを示す図であり、（ａ）は、同システムが自家用自動車（車両）に設けられ、同車両に向かう異なる４つの方向から到来する電波を受信している状態を示す模式図、（ｂ）は、同システムの回路ブロック図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the vehicle communication system which concerns on embodiment of this invention, (a) is provided in the private vehicle (vehicle), and the system is receiving the radio wave which comes from four different directions toward the vehicle. A schematic diagram showing the state, (b) is a circuit block diagram of the system. 本発明の実施形態に係る車両通信システムの基本動作を示すフローチャート図。The flowchart figure which shows the basic operation | movement of the vehicle communication system which concerns on embodiment of this invention.

Explanation of symbols

１…車両通信システム（ノイズ電波方向検知及び低減機能付き車両通信システム）、２…自家用自動車（車両）、１１…携帯機、１２…アンテナ要素、１２ａ，１２ｂ，１２ｃ，１２ｄ…指向性受信アンテナ（指向性受信アンテナ手段）、１３…受信機（アンテナ受信感度低下手段）、１４…アンテナ切換回路（アンテナ切離手段）、１５…受信回路（受信電波復調増幅手段）、１５ａ…フィルタ回路、１５ｂ…増幅回路、１５ｃ…復調回路、１６…ＲＳＳＩ回路（ノイズ電波変換手段）、１７…マイコン（ノイズ信号強度判定手段，運転者ＩＤコード照合手段）。 DESCRIPTION OF SYMBOLS 1 ... Vehicle communication system (vehicle communication system with noise radio wave direction detection and reduction function), 2 ... Private car (vehicle), 11 ... Portable machine, 12 ... Antenna element, 12a, 12b, 12c, 12d ... Directional receiving antenna ( Directional receiving antenna means), 13 ... Receiver (antenna reception sensitivity lowering means), 14 ... Antenna switching circuit (antenna separating means), 15 ... Reception circuit (received radio wave demodulation amplification means), 15a ... Filter circuit, 15b ... Amplifying circuit, 15c ... demodulating circuit, 16 ... RSSI circuit (noise radio wave converting means), 17 ... microcomputer (noise signal strength judging means, driver ID code checking means).

Claims

A plurality of directional receiving antenna means attached to a vehicle, capable of receiving radio waves coming from a direction surrounding the vehicle, and each selectively receiving radio waves from different specific directions;
Received radio wave demodulating and amplifying means for amplifying and demodulating radio waves received by each directional receiving antenna means;
Noise radio wave conversion means for converting the intensity of a noise radio wave received by each directional receiving antenna means and further amplified and demodulated by the received radio wave demodulation amplifying means into noise signal intensity;
In a vehicle communication system comprising noise signal strength determination means for comparing the noise signal strength with a predetermined level to determine the magnitude of both,
When it is determined that the noise signal intensity is greater than the predetermined level, the plurality of directional reception antenna units should effectively receive the directional reception antenna unit that has received a noise radio wave greater than the predetermined level. Further comprising an antenna separating means for separating from the received radio wave demodulating and amplifying means so as not to be used for receiving radio waves,
When a noise radio wave larger than the predetermined level is received by the plurality of directional reception antenna means, the directional reception antenna means that has received the noise radio wave larger than the predetermined level by the antenna disconnecting means is changed to the received radio wave. The directional receiving antenna means other than the directional receiving antenna means that has received the noise radio wave exceeding the predetermined level among the plurality of directional receiving antenna means is separated from the demodulation amplifying means for receiving the effective radio wave. A vehicle communication system with a noise radio wave direction detection and reduction function, characterized by being configured to be used.

The vehicle communication system according to claim 1,
Noise radio wave direction detection that is set to a maximum signal level in the range of the signal level of the noise radio wave that does not saturate the received radio wave demodulation amplification means by the noise radio wave received by the directional receiving antenna means, and Vehicle communication system with reduction function.

In the vehicle communication system according to claim 1 or 2,
The antenna disconnecting means is an antenna switching circuit for connecting and disconnecting each directional receiving antenna means and the received radio wave demodulating and amplifying means, and the directional receiving antenna means is set at regular intervals using the antenna switching circuit. Vehicle communication system with noise radio wave direction detection and reduction function configured to receive radio waves by switching to.

In the vehicle communication system according to any one of claims 1 to 3,
A vehicle communication system with a noise radio wave direction detection and reduction function in which noise radio waves received by the respective directional receiving antenna means belong to the UHF band.

In the vehicle communication system according to any one of claims 1 to 4,
A driver ID code verification means for verifying a first ID code for identifying the driver of the vehicle and a second ID code for identifying the authorized user of the vehicle;
A portable device possessed by the driver and transmitting a predetermined radio wave,
The effective radio wave is a predetermined radio wave transmitted from the portable device and includes the first ID code, and the first ID code is transmitted to the driver ID via the effective radio wave. The first ID code is checked against the second ID code transmitted to the code checking means, and the vehicle door is unlocked when it is confirmed that both ID codes match. Vehicle communication system with noise radio wave direction detection and reduction function.