【発明の詳細な説明】〔産業上の利用分野〕この発明は、自動車等に搭載するレーダ装置に関するも
ので、特に先行車輌の追従を比較的近距離で行なうのに
適した車載レーダ装置に係るものである．〔従来の技術〕近年の自動車台数増加により道路における渋滞の発生頻
度が高くなっており、特に都市部およびその周辺での一
般道、高速道の渋滞は日常茶飯事になっている．これら
渋滞道路においては運転操作に対する運転者の負担が著
しく増大し、運転者の疲労による判断能力低下等による
衝突事故等の頻度も増えている．このため、自動車には
機械的、電気的に衝突を回避するための自動車間保持装
置、車間警報装置、自動制動装置等の安全装置の搭載が
必要となってきており、さらに先行車自動追尾装置の開
発により運転者の負担を大幅に低減できる．これら装置
を有効に機能させるためには、自軍と先行車間の距離、
方向を知る車載レーダー装置が必要不可欠である．〔発明が解決しようとする課題〕従来、車間距離の検出力式としては、電波あるいは光パ
ルスを先行車に当てその伝搬時間より距離を測定する方
式がよく知られているが、かかる方式は上記渋滞時のご
とき平均車間距離が比較的小さい場合には伝搬時間が小
さすぎ距離の検出が困難である．近距離用の距離検出力
式としては、カメラのオートフォーカスに用いる測距装
置がよく知られている．かかる装置の方式としては、外
光を利用するパッシブ方式による二重像合致方式と、測
距装置自体から光を発するアクティブ方式による三角測
量方式が代表的であり、いずれの方式も距離の検出は可
能であるが、方向を検出することは困難である．かかる
三角測量方式を応用して、先行車までの距離と方向を求
める従来の車載レーダー装置としては、例えば、特開昭
４９−４３３２８号公報に示された方式がある。これは
、先行車輌の後部に光源を配して該光源より後方に光を
投射し、追従車輌に設けた複数の受光器間の受光光量の
差により先行車輌までの距離、方向を求めるようにした
ものであるが、かかる方式では複数の受光器間の受光光
量の差により距離、方向を算出しているため、光源や受
光器の汚れによる受光光量変化や、温度変化、経時変化
等での光源の発光量や個々の受光器受光感度の変化によ
る受光光量の変化が無視できず、しかもかかる受光光量
の変化が個々の受光器により異なるため、長期間にわた
る安定した距離や方向の検出動作が期待できないといっ
た課題があった．この発明は上記のごとき従来装置の課題を解決するため
になされたものであり、環境や光学素子の経時変化によ
らず長時間にわたり常時安定した距離、方向の検出動作
が可能な車載レーダ装置を得ることを目的とする．〔諜題を解決するための手段］この発明に係る車載レーダ装置は、先行車輌の後部に設
けられ後方に向けてパルス変調光を投射する光源を有す
る光源装置と、追従車輌の前部に所定間隔を隔てて設け
られ光軸が上記追従車輌軸に略平行な一対の受光光学系
と、両受光光学系の結像面に設けられ上記光源の像を結
像させる光電変換器と、この光電変換器の出力より上記
結像面での水平方向の結像位置を算出する結像位置算出
手段と、この結像位置算出手段の出力より先行軍輛まで
の距離と方向を求める距離・方向算出手段とを備えたも
のである．〔作 用〕この発明においては、先行車輌の後部に設けた光源から
後方に向けてパルス変調光を投射し、追従車輌の前部に
所定間隔を隔てて設けた一対の受光光学系の結像面に各
々設けられた充電変換器に上記光源の像を結像させ、両
光電変換器での上記光源の像の水平方向の結像位置を算
出することにより先行車輌までの距離と方向を求めるこ
とができる．〔実施例〕以下、この発明の一実施例を図について説明する．第１
図はこの発明による車載レーダ装置の構成図を示すもの
で、図において、ｌは先行車輌１００の後部中央に取付
けられた光源で、光源回路２により車輌後方へパルス変
調光９を投射する．光源１としては可視光ＬＥＤ等の可
視光源でもよいが、背景光等の雑音によるＳ／Ｎ比の低
下を防止するため、近赤外ＬＥＤ等の波長１ｐ程度の近
赤外光源が望ましく、以下の説明では近赤外Ｌ已Ｄを用
いている．またパルス変調光９は所定車輌ごとにパルス
の周期、発光時間等の異なったコード化された変調光と
するのが追尾車輌識別の上で有利である，３ａ，３ｂは
追従車輌２００の前部に取付けた左右１対の受光光学系
であって、両受光光学系３ａ，３ｂはその光軸が追従車
輌２００の車輌軸．と略平行となるように所定間隔離し
て配置されている．７は上記パルス変調光９を集光する
受光レンズ、８は集光レンズ７により集光した光源ｌの
像を結像させる光電変換器で先行車輌１００よりパルス
変調光９が投射されると各受光光学系３ａ．３ｂは受光
レンズ７によりパルス変調光９を集光し、充電変換器８
上に光源ｌの像を結像させる．このとき各受光光学系３
ａ，３ｂに可視光カットフィルタ（図示せず）を設ける
ことにより背景光をカットするのはＳ／Ｎ比向上に有利
である．上記充電変換器８は、光学系の倍率が非常に大
きいため受光レンズ７のほぼ焦点位置に結像面がくるよ
うに配置され、またその受光長の中心が受光光学系光軸
上にあるように配置してもよいが、図示するごとく、殆
んどの場合、光源ｌの結像位置は各受光光学系光軸に対
して追従車輌２００の車輌軸の反対側になるため、各々
の光電変換器８の有効受光長の中心をかかる方向に所定
距離離間させて設けるようにすれば、充電変換器８の受
光長を有効に利用できる．４ａ，４ｂは上記光電変換器８．８上の水平方向結像位
置ＸＲ，ＸＬを算出する結像位置算出手段で、その出力
はそれぞれ距離・方向算出手段５に出力される．一方、
充電変換器８の総パルス電流ｉＴはコード識別手段６に
出力されて先行車輌１００の光源１のパルスコードの変
化を監視し、先行車輌１００が入替わったり、先行車輌
１００と追従車輌２００の間の障害物を検知したような
場合には識別異常信号を距離・方向算出手段５に出力す
る．距離・方向算出手段５は結像位置ＸＲ，ＸＬにより
先行車輌までの距離Ｌと方向θを計算するとともに、別
に入力された識別異常信号を監視し、追尾中の先行車輌
１００に相違ないかを判定し、距離Ｌと方向θを出力す
る．ｗＡ別異常信号を検知したような場合には距＠Ｌと
方向θの信号を相応に変化させて出力させればよい．第
２図は結像位置算出手段４のブロック回路構成図であり
、光電変換器８としてＰＳＤ （半導体位置検出器）を
用いた例を示している，ＰＳＤ８では、光源１からのパ
ルス変調光９が受光光学系３に入射し、ＰＳＤＢ上で結
像したとき、像１０の光重心位置とＰＳＤ８中心との距
離をＸとすると、距＃ＩＸはＰＳＤ８の両端の電極８ａ
，８ｂから出力される光電流１ａ，ｉｂとＰＳＤ１３の
有効受光長Ｄより、Ｘ ＝ Ｄ （ （ｌａ−ｉｂ） ／ （ｉａ＋ｉｂ）
） ／ ２ ・＝（１）で得られる．結像位置算出手
段４はＰＳＤ８の光電流ｉａ，ｉｂを各々交流増幅器４
１ａ，４ｌｂで増幅して信号となるパルス電流成分のみ
を抽出した後、ピークホールド回路４２ａ，４２ｂによ
りＤＣ電圧信号Ｖａ，Ｖｂに変換し、減算回路４３，加
算回路４４．割算回路４５を介して上記（１）式を計算
し、結像位置Ｘとして出力する．また、ハルス加算回路
４６によりＰＳＤ８の総パルス電流ｉＴが光源１のパル
スコード識別信号としてコード識別手段６に出力される
．第３図は距離・方向算出手段５の距離・方向算出原理の
説明図であり、図において先行車輌１００と追従車輌２
００間の距＠Ｌと方向θは、各受光光学系３ａ．３ｂの
ＰＳＤ８における光源１のＰＳＤ８中心からの結像位置
ＸＲ，ＸＬより、各受光光学系３ａ，３ｂ間の基線長２
Ｂ，受光レンズ７とＰＳＤ８までの距＠Ｆ，ＰＳＤ８の
有効受光長Ｄ，ＰＳＤ８中心の受光光学系光軸からのシ
フト量ΔＤを用いてθ−ｍ−’ （（ＸＲ−ＸＬ）／ ２ Ｆ ）
・・・（２）Ｌ −２ＢＦ／ （ （ＸＲ−ＸＬ＋２
ΔＤ−Ｄ）ｃｍθ）−（３）として得られる．但し方向
θは追従車輌２００と先行車輌１００の車輌軸のなす角
度、距１１１１Ｌは追従車輌２００の受光光学系３ａ，
３ｂの基線長中心と先行車輌１００の光源１との距離で
示される．即ち、以上の構成によれば先行車輌１００ま
での距１ｉ１Ｌと方向θが、受光光学系３ａ，３ｂにお
ける光源ｌの結像位置により決定されるため、光源１の
発光量や受光光学系３ａ，３ｂの受光効率が変化しても
安定な動作ができるという利点がある．第４Ｆｊ！Ｉはこの発明の他の実施例の結像位置算出手
段４の回路構成図であり、光電変換器として一対のフォ
トダイオードｌｌａ，ｌｌｂを用いた例を示している．
スオトダイオードｌｌａ，ｌｌｂ上に光源１の像１０が
結像したとき、フォトダイオード１１ａ．１ｌｂには像
１０が各光電面にがかった面積比に相当した分割光電流
ｉａ，ｉｂが流れる．したがってこの光電流ｉａ，ｉｂ
を第２図と同様な結像位置算出回路４に入力することに
より結像位置Ｘを検出できる．かかる構成では光電変換
器が安価となり、レーダ装置をより安価に構成できると
いう利点がある．第５．６．７図はこの発明の他の実施例の光学系の積成
図である．まず第５図は受光光学系３に受光レンズ７と
共に円筒レンズ１２を配して、充電変換器８上にその暢
Ｈより長い光源１の縦長の像１０を形成させる．かかる
構成では先行車輌１００や追従車輌２０Ｇの振動、ピッ
チング等で光源１と受光光学系３の光軸の水平がずれて
も充電変換器８上に像１０の一部が常にかかるため、路
面等の状嘘によらず安定した◆ｈ作が可能となる．この
図では受光レンズ７と円筒レンズ１２を分けて示したが
、受光レンズ７を非球面レンズとして円筒レンズ１２の
機能を付加すればレンズ系が簡単となり受光光学系３を
より明るくできる．また第６図は、受光光学系３に円筒
レンズｌ２を配する代わりに、光源ｌの側に円筒レンズ
１２を配して充電変換器８上に同樺な縦長の像１０を形
成させるもので、このような構成でも上記と同様な効果
が期待できるとともに円筒レンズｌ２が１つでよいとい
う利点がある．さらに、第７図は縦方向に複数の光源１
ａ，ｌｂ，Ｉｃを各々距＠ｗ＠して設けることにより、
充電変換器８上に縦方向に分布した像１ ０ ａ，
１ ０ ｂ， １ ０ ｃを形成させ、距離Ｗを、最
低車間検知距離をＬ ｓｉｎ として光電変換器８の輻
Ｈに対しＷ＜｝ｌ−Ｌｓｉｎ ／ ｆ （ ｆ ：受光
レンズｌ２の焦点距離）なるよう配置することにより、
光軸の水平がずれても、充電変換器８上に光源１ａ．ｌ
ｂ，ｌｃの像１０ａ．１０ｂ，１０ｃの内のいずれかが
かかる構成としており、やはり上記と同樺な効果が期待
できる．上記実施例では円筒レンズｌ２の使用や光源の
複数化により光電変換器８上に縦長の像を形成させるも
のとしたが、反射鏡、プリズム、光拡散体等他のビーム
形成手段を用い縦長の像を形成させてもよい．なお上記実施例では、この発明を自動車の車載レーダに
適用した場合につき説明したが、工場での自動搬送車等
、他の車輌用の車載レーダとして適用できることは言う
までもない．〔発明の効果〕以上説明したようにこの発明によれば、先行車輌の後部
に設けた光源からパルス変調光を投射し、追従車輌の前
部に設けた一対の受光光学系に上記光源の像を結像させ
、両受光光学系の結像面での光源の像位置より先行車輌
までの距離と方向を求めるように構成したので、背景光
の変化や光源、受光系の汚れ、温度変化、経時変化等で
の光源の発光量や受光系受光感度の変化等によらず、常
に安定して先行車輌までの車間１１ｚｌｌｌや方向を正
確に検出できる効果がある．[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a radar device mounted on a vehicle, etc., and particularly to a vehicle-mounted radar device suitable for following a preceding vehicle at a relatively short distance. It is something. [Prior Art] Due to the recent increase in the number of automobiles, congestion on roads has become more frequent, and congestion on public roads and expressways, especially in and around urban areas, has become a daily occurrence. On these congested roads, the driver's burden on driving operations has increased significantly, and the frequency of collisions and other accidents due to reduced judgment ability due to driver fatigue is also increasing. For this reason, it has become necessary for automobiles to be equipped with safety devices such as distance keeping devices, distance warning devices, and automatic braking devices to mechanically and electrically avoid collisions, as well as automatic tracking devices for preceding vehicles. The development of this technology will significantly reduce the burden on drivers. In order for these devices to function effectively, the distance between your troops and the preceding vehicle,
An in-vehicle radar device that knows direction is essential. [Problems to be Solved by the Invention] Conventionally, as a method for detecting inter-vehicle distance, a method in which radio waves or optical pulses are applied to the preceding vehicle and the distance is measured from the propagation time is well known. When the average inter-vehicle distance is relatively small, such as during traffic jams, the propagation time is too short and it is difficult to detect the distance. A distance measuring device used for camera autofocus is well known as a distance detection system for short distances. Typical methods of such devices are a passive dual image matching method that uses external light, and an active triangulation method that emits light from the distance measuring device itself.In both methods, distance detection is difficult. It is possible, but it is difficult to detect the direction. An example of a conventional vehicle-mounted radar device that utilizes such a triangulation method to determine the distance and direction to a preceding vehicle is the method disclosed in Japanese Patent Application Laid-Open No. 49-43328. This is a method in which a light source is placed at the rear of the leading vehicle, and light is projected backward from the light source, and the distance and direction to the leading vehicle is determined by the difference in the amount of light received by multiple receivers installed in the following vehicle. However, in this method, the distance and direction are calculated based on the difference in the amount of light received between multiple receivers. Changes in the amount of received light due to changes in the amount of light emitted by the light source and the light receiving sensitivity of individual receivers cannot be ignored, and furthermore, changes in the amount of received light vary depending on the individual receiver, making it difficult to perform stable distance and direction detection operations over long periods of time. There were some issues that did not meet expectations. This invention was made to solve the above-mentioned problems with conventional devices, and provides an in-vehicle radar device that is capable of constantly stable distance and direction detection operations over long periods of time regardless of changes in the environment or optical elements over time. The purpose is to obtain. [Means for Solving the Problem] An on-vehicle radar device according to the present invention includes a light source device provided at the rear of a leading vehicle and having a light source that projects pulse modulated light toward the rear, and a light source device provided at the front of a following vehicle. a pair of light-receiving optical systems that are spaced apart and whose optical axes are substantially parallel to the following vehicle axis; a photoelectric converter that is provided on the imaging plane of both light-receiving optical systems and forms an image of the light source; An imaging position calculation means for calculating the horizontal imaging position on the imaging plane from the output of the converter, and a distance/direction calculation for calculating the distance and direction to the preceding military vehicle from the output of the imaging position calculation means. It is equipped with the means. [Function] In this invention, pulse modulated light is projected rearward from a light source provided at the rear of the leading vehicle, and an image is formed by a pair of light-receiving optical systems provided at a predetermined distance from each other at the front of the following vehicle. The distance and direction to the preceding vehicle are determined by forming an image of the light source on each charging converter provided on each surface, and calculating the horizontal imaging position of the image of the light source on both photoelectric converters. be able to. [Example] An example of the present invention will be described below with reference to the drawings. 1st
The figure shows a configuration diagram of an on-vehicle radar device according to the present invention. In the figure, l is a light source installed at the center of the rear of a preceding vehicle 100, and a light source circuit 2 projects pulse-modulated light 9 toward the rear of the vehicle. The light source 1 may be a visible light source such as a visible light LED, but in order to prevent the S/N ratio from decreasing due to noise such as background light, a near-infrared light source with a wavelength of about 1p such as a near-infrared LED is preferable. The explanation uses near-infrared L and D. Further, it is advantageous for the identification of the following vehicle to use the pulse modulated light 9 as a coded modulated light having a different pulse period, light emitting time, etc. for each predetermined vehicle. A pair of left and right light receiving optical systems are attached to the left and right light receiving optical systems 3a and 3b, and the optical axes of both light receiving optical systems 3a and 3b are aligned with the vehicle axis of the following vehicle 200. They are placed at a predetermined distance so that they are approximately parallel to each other. 7 is a light receiving lens that collects the pulse modulated light 9, and 8 is a photoelectric converter that forms an image of the light source l focused by the focusing lens 7. When the pulse modulated light 9 is projected from the preceding vehicle 100, each Light receiving optical system 3a. 3b collects the pulse modulated light 9 using the light receiving lens 7, and connects it to the charging converter 8.
An image of light source l is formed on top. At this time, each light receiving optical system 3
Cutting out background light by providing visible light cut filters (not shown) in a and 3b is advantageous for improving the S/N ratio. Since the magnification of the optical system is very high, the charging converter 8 is arranged so that the imaging plane is almost at the focal point of the light-receiving lens 7, and the center of its light-receiving length is on the optical axis of the light-receiving optical system. However, as shown in the figure, in most cases, the imaging position of the light source l is on the opposite side of the vehicle axis of the tracking vehicle 200 with respect to the optical axis of each light-receiving optical system, so each photoelectric conversion By arranging the center of the effective light receiving length of the charging converter 8 at a predetermined distance in this direction, the light receiving length of the charging converter 8 can be used effectively. 4a and 4b are imaging position calculation means for calculating the horizontal direction imaging positions XR and XL on the photoelectric converter 8.8, and their outputs are outputted to the distance/direction calculation means 5, respectively. on the other hand,
The total pulse current iT of the charging converter 8 is output to the code identification means 6 to monitor changes in the pulse code of the light source 1 of the leading vehicle 100, and detect changes in the leading vehicle 100 or between the leading vehicle 100 and the following vehicle 200. When an obstacle is detected, an identification abnormality signal is output to the distance/direction calculation means 5. The distance/direction calculation means 5 calculates the distance L and direction θ to the preceding vehicle based on the imaging positions XR and XL, and monitors a separately input identification abnormality signal to determine whether the preceding vehicle 100 is the one being followed. Determine and output distance L and direction θ. If an abnormal signal by wA is detected, the distance @L and direction θ signals may be changed accordingly and output. FIG. 2 is a block circuit diagram of the imaging position calculating means 4, and shows an example in which a PSD (semiconductor position detector) is used as the photoelectric converter 8. In the PSD 8, the pulse modulated light 9 from the light source 1 is enters the light-receiving optical system 3 and forms an image on the PSDB. If the distance between the center of gravity of the image 10 and the center of the PSD 8 is X, then the distance #IX is the distance between the electrodes 8a at both ends of the PSD 8.
, 8b and the effective light receiving length D of PSD 13, X = D ((la-ib) / (ia+ib)
) / 2 ・=(1). The imaging position calculating means 4 inputs the photocurrents ia and ib of the PSD 8 to AC amplifiers 4, respectively.
1a, 4lb to extract only the pulse current component that becomes the signal, and then convert it into DC voltage signals Va, Vb by the peak hold circuits 42a, 42b, and then the subtracter circuit 43, adder circuit 44. The above equation (1) is calculated via the division circuit 45 and output as the imaging position X. Further, the total pulse current iT of the PSD 8 is outputted to the code identification means 6 by the Hals adder circuit 46 as a pulse code identification signal of the light source 1. FIG. 3 is an explanatory diagram of the distance/direction calculation principle of the distance/direction calculation means 5. In the figure, the leading vehicle 100 and the following vehicle 2 are
The distance @L and direction θ between each light receiving optical system 3a. From the imaging positions XR and XL from the center of PSD 8 of light source 1 in PSD 8 of 3b, the base line length 2 between each light receiving optical system 3a and 3b is determined.
B, Distance between light receiving lens 7 and PSD8 @F, Effective light receiving length D of PSD8, Shift amount ΔD from the light receiving optical system optical axis at the center of PSD8, θ-m-' ((XR-XL)/2 F )
...(2)L -2BF/ ((XR-XL+2
It is obtained as ΔD-D)cmθ)-(3). However, the direction θ is the angle formed by the vehicle axes of the following vehicle 200 and the preceding vehicle 100, and the distance 1111L is the light receiving optical system 3a of the following vehicle 200,
3b and the light source 1 of the preceding vehicle 100. That is, according to the above configuration, the distance 1i1L and the direction θ to the preceding vehicle 100 are determined by the imaging position of the light source 1 in the light receiving optical systems 3a, 3b, so that the amount of light emitted by the light source 1 and the light receiving optical system 3a, 3b are determined. It has the advantage of stable operation even if the light receiving efficiency of 3b changes. 4th Fj! I is a circuit diagram of the imaging position calculating means 4 according to another embodiment of the present invention, and shows an example in which a pair of photodiodes lla and llb are used as photoelectric converters.
When the image 10 of the light source 1 is formed on the photodiodes lla, llb, the photodiodes 11a. Divided photocurrents ia and ib corresponding to the area ratio of the image 10 covering each photocathode flow through 1lb. Therefore, this photocurrent ia, ib
The image forming position X can be detected by inputting the image forming position X into the image forming position calculation circuit 4 similar to that shown in FIG. This configuration has the advantage that the photoelectric converter is inexpensive and the radar device can be configured at a lower cost. Figures 5.6.7 are stacked diagrams of an optical system according to another embodiment of this invention. First, in FIG. 5, a cylindrical lens 12 is arranged together with a light receiving lens 7 in a light receiving optical system 3 to form a vertically elongated image 10 of a light source 1 longer than its width H on a charging converter 8. In such a configuration, even if the optical axes of the light source 1 and the light receiving optical system 3 become out of horizontal due to vibrations, pitching, etc. of the leading vehicle 100 or the following vehicle 20G, a portion of the image 10 will always be on the charging converter 8, so that the image 10 will not be affected by the road surface, etc. Stable ◆h production is possible regardless of the situation. In this figure, the light-receiving lens 7 and the cylindrical lens 12 are shown separately, but if the light-receiving lens 7 is an aspherical lens and the function of the cylindrical lens 12 is added, the lens system can be simplified and the light-receiving optical system 3 can be brighter. Moreover, in FIG. 6, instead of arranging the cylindrical lens 12 in the light receiving optical system 3, a cylindrical lens 12 is arranged on the side of the light source 1 to form a birch-like vertically elongated image 10 on the charging converter 8. Even with this configuration, the same effects as above can be expected, and there is an advantage that only one cylindrical lens l2 is required. Furthermore, FIG. 7 shows a plurality of light sources 1 in the vertical direction.
By providing a, lb, and Ic with distances @w@,
Image 1 0 a, distributed vertically on charging converter 8
1 0 b, 1 0 c, the distance W is set to the minimum inter-vehicle detection distance L sin , and the radiation H of the photoelectric converter 8 is W<}l−L sin / f (f: focal length of the light receiving lens l2). By arranging it so that
Even if the optical axis is not horizontal, the light source 1a. l
b, lc image 10a. Either one of 10b and 10c has such a configuration, and the same effect as above can be expected. In the above embodiment, a vertically elongated image is formed on the photoelectric converter 8 by using the cylindrical lens l2 and by providing a plurality of light sources. It is also possible to form an image. In the above embodiment, the present invention is applied to an on-vehicle radar for an automobile, but it goes without saying that it can also be applied to an on-vehicle radar for other vehicles such as automatic guided vehicles in factories. [Effects of the Invention] As explained above, according to the present invention, pulse modulated light is projected from a light source provided at the rear of a leading vehicle, and an image of the light source is projected onto a pair of light receiving optical systems provided at the front of a following vehicle. The system is configured to form an image and determine the distance and direction to the preceding vehicle from the image position of the light source on the imaging plane of both light receiving optical systems, so changes in background light, dirt on the light source and light receiving system, temperature changes, This has the effect of always stably and accurately detecting the distance and direction to the preceding vehicle, regardless of changes in the amount of light emitted by the light source or the light receiving sensitivity of the light receiving system due to changes over time.
【図面の簡単な説明】[Brief explanation of the drawing]構成図、第３図は距離・方向算出原理の説明図、第４図
は結像位置算出手段の他の例のブロック回路構成図、第
５図〜第７図はこの発明による他の実施例の光学系の各
々の構成図である．１ ・・・光源、２・・・光源回路
、３ａ，３ｂ＝受光光学系、４ａ，４ｂ−・・結像位置
算出手段、５・・・距離・方向算出手段、８・・・充電
変換口、１００・・・先行車輌、２ ０ Ｇ −・・追
従車輌．なお、図中同一符号は同一又は相当部分を示す．Ｌｅ3 is an explanatory diagram of the principle of distance/direction calculation, FIG. 4 is a block circuit diagram of another example of the imaging position calculation means, and FIGS. 5 to 7 are other embodiments according to the present invention. This is a configuration diagram of each optical system. 1...Light source, 2...Light source circuit, 3a, 3b=light receiving optical system, 4a, 4b--imaging position calculation means, 5...distance/direction calculation means, 8...charging conversion port , 100... Leading vehicle, 20 G -... Following vehicle. In addition, the same symbols in the figures indicate the same or equivalent parts. L e