CA1148239A - System for measuring current position and/or moving direction of vehicle - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A reference station is provided at a fixed position.
The station is adapted to transmit a scanning signal the transmitting direction of which is scanned in succession in different directions, a positional information signal representative of the position of the reference station and an azimuth information signal representative of a particular azimuth. A vehicle moving with respect to the reference station is provided with receivers at at least three positions spaced apart from each other by given distances, so that when the vehicle moves in the service area of the reference station the signals transmitted by the reference station are received. The current position of the vehicle and the moving direction of the vehicle are operated based on a time or phase difference from receipt of the particular azimuth signal until receipt of the scanning signal by the at least three receivers, the position of the reference station and the distances between the at least three receivers provided in the vehicle.

Description

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The present invention relates to a system for measuring the position and/or the direction of a moving vehicle~ More specifically, the present invention relates to a system for automatically measuring the position and dirçction of a moving vehicle such as an automobile, aircra~, ship and the like which moves along a given path.
Various systems, such as Loran, Decca, Omega and the like, using electromagnetic radiation, have been used for measuring the position and direction of a moving vehicle. Such systems, however, require a plurality of, and at least three, reference stations installed at different locations spaced relatively far from each other. Thus, no system has been proposed which can detect the position and direction of a moving vehicle based on a reference station installed at a single location.
Accordingly, an object of the present invention is ` to provide a novel system for measuring the position and/or the direction of a moving vehicle.
According to an aspect of the invention there is provided a system for measuring at least one of ~he current position and the direction of a moving vehicle, comprises transmitting means installed at a reference location, the transmitting means comprising first transmitting means for transmitting an azimuth scanning signal being scanned in succession in different directions, second transmitting means for transmitting a location information signal repre-senting the reference location of the transmitting means, and third transmitting means for transmitting an azimuth associated information signal containing information concerning a predetermined azimuth, receiving means for receiving the - 1 - ", ~ .-azimuth scanning signals at at least three positions spaced apart from each other by predetermined distances and for receiv-ing the location information signal and the azimuth associated informa~ion signal at at least one of the at least three posi-tions, and information processing means borne on the moving vehicle, the information processing means-being structured to evaluate at least one of the current position and the direction of the moving vehicle based on the information concerning the respective time periods from receipt of the azimuth associated information signal until receipt of the azimuth scanning signal at the at least three positions, the location information and the information concerning the predetermined distances between the at least three positions.
The transmitting means installed at a predetermined fixed location will throughout the following be also identified as the "reference stations".
According to a preferred embodiment of the present invention, the information processing means may be implemented by a microcomputer, wherein the control program of the micro-computer is stored in a read-only memory. The read-only memory is also loaded with a prescribed operation formula. ~ngles between the at least three receiving positions with respect to the location of the reference station are evaluated, and these angIes, the location of the reference station and the distances between the at least three receiving positions are applied to the prescribed operation formula as read from the read-only memory, whereiby the absolute locations of the at least three receiving positions are evaluated. The direction of the vehicle is evaluated based on f he absolute locations of ,. I
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these at least three receiving positions.
According to a further preferred embodiment of the present invention, the angle of the vehicle with respect to the reference station is evaluated based on the angles of the at least three receiving posi-tions with respect to the location of the reference station; and the straight line dis-tance from the vehicle to the reference station is evaluated based on the location corresponding to the maximum angle among the said angles and the location corresponding to the minimum angle among the said angles, whereupon the position of the vehicle is evaluated based on the angle of the vehicle with respect to the reference station and the straight line distance.
In a further pre~erred embodiment of the present invention, at least three receiving units are provided in a portable casing, so that the same may be detachably provided in a vehicle such as an automobile, ship or the like~ The casing is provided with at least one expandible/contractible member and at least one receiving unit is pxovided at the variable position end of the expandible/contractible member. When carrying the casing, the expandible/contractible member is contracted, so that the system may be compactO As a result~
the system can be borne in any type of vehicle and hence the position and/or direction of the vehicle can be measured.
Preferably, the casing is provided with a level, so that display of position and/or direction is prevented when the vehicle is not horizontal. As a result, erroneous data is prevented from being displayed when the vehicle or the system is not horizontal.

In still a further preferred embodiment of the present invention, the position and/or direction of a vehicle are evaluated based on the time differences between the times of recepkion of the scannin~ si~nal at the at least three receiving positions, the location of the reference station and the angular information obtained from the center of the triangle defined by the at least three receiving positions and in accor-dance with a predetermined arithmetic formula.
In still another preferred embodiment of the present invention wherein the invention is embodied in an aircraft, the angle of elevation and the angle of pitch are detected and the distances between the at least three receiving positions are corrected based on the detected angles. As a result, the position and/or the direction can be accurately evaluated even when the aircraft is not horizontal.
In still a further embodiment of the present inven-tion, a plurality of reference stations are installed at dif-ferent positions. If and when the vehicle while receiving a signal from one reference station has that signal interrupted by an obstacle, the system is controlled to receive a signal from another reference station which is not interrupted by the obstacle. Accordingly, the vehicle can continually evaluate its positon and/or direction.
In still a further preferred embodiment of the pre-sent invention, a plurality of reference stations are installed at a plurality of different predetermined fixed locations and the position and/or direction of the vehicle is evaluated responsive to each of the signals received from the plurality of reference stations r Preferably, the mean value of the position and/or the direction of the vehicle is evaluated based ,~

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on the plurality of signals received from the plurality of reference stations, whereby the position and/or the direction of the vehicle can be measured with more accuracy.
Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:
Fig. 1 is a diagrammatic view for explaining the principle of one embodiment of the present invention;
Fig. 2 is a graph showing the wave forms of the azimuth associated information signal and the azimuth scanning signal;
Figs. 3A and 3B, shown on the same sheet as Fig. 1, are block diagrams showing one example of a transmitter provided in a refe~ence station;
Fig. 3C, shown on the same sheet as Fig. 1, is a graph showing the wave forms ~f the Iocation information signal representative of the location of the reference station;
Fig. 4 is a diagrammatic view showing a system arrangement in an aircraft as an example of a vehicle for use in the present invention;
Fig. 5 is a block diagram showlng one example of a receiver borne on the aircraft of Fig. 4;
Fig. 6 is a block diagram showing one example of a ;
microcomputer used as a central processing unit;
Figs. 7A, 7B and 7C are diagrammatic views of dif-ferent examples of displays for use in the present invention;
Figs. 8A and 8B, shown on the same sheet as Fig. 2, are graphs for explaining the principle of another embodiment of the present invention;

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Fig. ~ is a flow chart for explaining the embodiment shown in Figs. 8A and 8B;
Fig. 10 is a view for explaining the principle of a further embodiment of the present invention;
Fig. 11 is a view for explaining the principle of still a further embodiment of the present invention;
Fig. 12A is a block diagram showing another example of a transmitter for use in the present invention;
Fig. 12B is a graph showing one example of the azi-muth scanning signal being transmitted by the Fig. 12A trans-mitter;
Fig. 13 is a graph showing one example for evaluat-ing the angle of the azimuth scanning signal shown in Fig. 12B;
Fig. 14 is a view for explaining the principle of another embodiment of the present invention;
Figs. 15A and 15B are views showing one example of a level employed in a further embodiment of the present invention;
FigO 16 is a block diagram of a further embodiment of the present invention;
Fig. 17A and 17B are views for showing a further embodiment of the present invention;
Figs. 18A, 18B and 18C are views for explaining the pxinciple of a further embodiment of the present'invention;
Figs. 19 and 20 are views for explaining the princi-ple of a further embodiment of the present invention;
Fig. 21 is a block diagram of the embodiment shown in Figs. 19 and 20;
Fig. 22 is a view explaining the principle of still a further embodiment of the present invention;

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Fig. 23 is a block diagram of a transmitter employed in the Fig. 22 embodiment;
Fig. 24 is a graph explaining the timing relation of the operation of the respective receivers shown i~ Fig. 23;
Figs. 25A and 25B are block diagrams of receiving means included in still a further embodiment of the present invention;
Figs. 26A and 26B are block diagrams of receiving means included in still a further embodiment of the present invention; and Figs. 27 and 28 are views for showing still further embodiments of the present inventions.
Fig. 1 is a diagrammatic view for explaining the principle of one embodiment of the present invention.
Reference station 1 is installed in a predetermined reference location. Assuming that the moving vehicle is an aircraft 2, then the reference station 1 may he, for example, installed in a predetermined location (Xa, Ya) in the vicinity of a guide path of the aircraft. As to be more fully described subse- :
quently with reference to Figs. 3A and 3~, the reference station 1 is provided with a transmitter for transmitting an azimuth scanning signal which comprises a directional continual wave which is scanned in succession in all the different azimuthal directions starting from a predetermined azimuth, say the north~
Such azimuth scanning signal can be transmitted by se~uentially rotating a transmitting antenna having an extremely sharp directivity. The reference station 1 is further provided with a transmitter for transmitting an azimuth associated information signal representative of the said specified azimuth such as the ~B~39 north at the time when the direction of transmission of the azimuth scanning signal is brought to the said prescribed azimuth such as the north. The reference station l is further prQvided with a transmitter for transmitting a location infor-mation signal representative of the location (Xa, Ya) of the reference station 1. The two latter mentioned transmitters for transmitting the azimuth associated information signal and the location information signal are structured to transmit these signals non-directionallyO
On the other hand, a moving aircraft 2 for example, is provided with at least three receivers, (see Figs. 4 and 5).
These may be provided at a first position 21 at the front end of the aircraft 2, a second position 22 at the left main wing of the aircraft 2 spaced apart from the first position 21 by a predetermined distance dl, and a third position 23 at the right main wing of the aircraft 2 spaced apart from the second location 22 by a predetermined distance d2 and spaced apart from the first location 21 by a predetermined distance d3 for receiving the azimuth scanning signal, the azimuth associated information signal and the location information signal, respect-ively. The receivers provided at the positions 21, 22 and 23 are enabled to receive the aboved described three signals, if and when the aircraft 2 moves in the service area of the reference station l.
Fig. 2 is a graph showing wave forms of the azimuth associated information signal and the azimuth scanning signal.
Now referring to Figs~ 1 and 2, one principle of the present invention will be described. If and when the reference station l transmits the azimuth associated information signal N represen-tative of the prescribed azimuth, say the north at the times 8~

shown in Fig. 2, then the receivers at the three positions 21, ~2 and 23 on the aircraft 2 moving in the service area of the reference station 1 receive the above described azimuth associated information signal N. Thus it follows that the reference station 1 transmits the azimuth scanning signal, with the very sharp directivity, in the specified azimuth say the north just at the instants when the azimuth associated information signal N is transmitted. Thereafter the scanning signal is transmitted with the very sharp directivity being changed successively from the north azimuth. Then, referring to Fig. 1, the receiver at the position 23 of the aircraft 2 ~irst receives the azimuth scanning signal and then the receiver at the position 22 of the aircraft 2 receives the azimuth scan-ning signal and finally the receiver at the position 21 of the aircraft receives the azimuth scanning signal. More specifi-cally, the receiver provided at the position 21, first receives the prescribed azimuth associated information signal N and after a delay of the time period tl the same receives the azimuth scanning signal S. The receiver at the position 22 first re-ceives the azimuth associated information signal N and then re-ceives the azimuth scanning signal S' with a delay of the time period t2. The receiver at the position 21 first receives the azimuth associated information signal N and then receives the azimu~h scanning signal S'' with a delay of the time period t3.
The data concerning the time periods tl, t2 and t3 is applied, for evaluation, to a microcomputer carried on the aircraft 2 for the purpose of the arithmetic operation to be described subsequently. The microcomputer is programmed to read out from a read-only memory, not shown, the gradients al, a2 and a3 of the straight lines lying between each of the

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respective positions 21, 22 and 23 and the location of the reference station 1, with the azimuth of the north as a refer-ence, based on the above described time data. More specifically, ~he angles ~ 2, and ~3 of ~he respective positions with respect to the specified a2imuth, say the north, of the reference station 1 are evaluated based on the above described time periods tl, t2 and t3. Various such angles with respect to various time periods may be preloaded as a table in a read-only memory, not shown, so that the corresponding angles may be read out as a function of such time periods by reference to such a table. The gradients al, a2 and a3 of the straight lines connecting the each of positions 21, 22 and 23 and the reference station 1 are then evaluated based on the above described angles ~ 2 and ~3. More speci~ically, such gradients al, a2 and a3 are evaluated by the following equations (1), (2), and (3), respectively:
al = tan~1 ---------------------------(1) a2 = tan~2 ---------------------------(2) a3 = tan~3 -~ ---------------(3) Thus, the gradients of the straight lines connecting the each of positions 21, 22 and 23 and the reference station 1 can be evaluated. As an alternative to the method of evaluation described it is possible to prepare a table of the relationships between various angles and the corresponding gradients, store the table in a read-only memory, and read out the evaluations in comparison with the table.
Formulae representing the straight lines connecting the each of positions 21, 22 and 23 and the reference station 1 3Z3~

may be evaluated based on the location (Xa, Ya) where the reference station 1 is installed. More specifically, the formula of the straight line connecting the position 21 and the location of the reference station 1 may be expressed by the following equation (4).
Yl - Ya = al (Xl - Xa) ----------(4) It can be determined that the position 21 is on the straight line defined by the equation (4). Similarly, the formula representing the straight l.ine connecting the position 22 and the reference station 1 may be expressed by the following equation (5). ~.-Y2 - Ya = a2(X2 - Xa) ----------(5) .
Now it can be determined that the position 22 is on the straight line defined by the equation (5). Similarly, the formula representing the straight line connecting the posi-tion 23 and the location of the reference station 1 may be expressed by the following equation (6).
Y3 - Ya = a3(X3 - Xa) ----------(6) Thus, it can be determined that the position 23 is on the straight line defined by the equation (6)o The distances dl, d2 and d3 between the positions 21, 22 and 23 on the aircraft 2 may be expressed by the follow-ing equations (7), (8) and (9).

dl = ~ (Xl - X2)2 + (Yl - Y2)2 ___________(7) d2 = J (X2 - X3) + (Y2 _ y3)2 -----------(8) d3 = J (Xl - X3)2 + (Yl _ y3)2 ___________(9) Furthermore, the formulae representing the straight lines connecting the positions 21, 22 and 23 may be expressed .; .

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by the followiny equations (10), (11) and (12).
Yl - Y2 = bl(Xl - X2) -------------(10) Y2 - Y3 = b2(X2 - X3) -------------(11) Y1 - Y3 = b3(Xl - X3) -------------(12) Therefore, the constants bl, b2 and b3 representing the gradients of the respective straight lines may be expressed by the following equations (13, (14) and (15).
bl yl - Y2 ________ __------(13) Y2 - Y3 - ---- -- --- -- (14) b2 = X2 --X3 b _ Yl ~ Y3 ------------------(15)

3 Xl --X3 In the above described equations, the quantities Xa, Ya, al, a2, a3, dl, d2 and d3 are known while the quanti-ties Xl, Yl, X2, Y2, X3, and Y3 are unknown; however, these unknown quantities Xl, Yl, X2, Y2, X3, Y3 can be evaluated by solving the above described simultanuous equations (1) to (15).
An arithmetic operation for solving such simultanuous equations can be advantageously performed by using a micro-computer, for example. By evaluating the positional data (X1, Yl), (X2, Y2), and (X3, Y3) of the positions 21, 22, and 23 on the aircraft 2, the current position and -th~ direction : of the moving aircraft 2 can ~e simply determined. More specifically, the current position of the aircraft~2 per se can be considered as represented by the data (Xl, Yl) of the position 21. On the other hand, the direction of the aircraft can be obtained by dividing the distance d2 by two, and by obtaining the formula of the straight line connecting the said two-divided point and the position 21, wherein the direction 35~

of the thus obtained straight line can be considered as the moving direction or azimuth of the aircraft 2.
Now referring to Figs. 3A and 3B, a transmitting equipment 100 installed in the reference station 1 will be described. Fig. 3A is a block diagram of a transmitter por-tion for transmitting the azimuth scanning signal and the azimuth associated information signal including the information representative of a specified azimuth when the azimuth scan- -:
ning signal is directed to a specified azimuth say the north, while Fig. 3B is a block diagram showing a transmitter portion for transmitting the location information signal representative of the location (Xa, Ya) of the reference station 1.
Referring to Fig. 3A, an oscillator 101 i5 provided to generate a continual oscillation signal serving as the above described azimuth scanning signal. The oscillation output of the oscillator 101 is amplified by a power amplifier 102 and is led to an antenna 103~ The antenna 103 is implemented by a parabola antenna, for example, having a very sharp unidirectional directivity. Such an antenna having a uni-directional directivity is well-known to those skilled in the art. The unidirectional directivity antenna 103 is rotated by means of a rotation driving means 104~ whereby the direc-tion o~ the unidirectivity is changed in succession and thus the azimuth or direction is scanned in succession in all the different directions. The rotation driving means 104 for 3~

example, comprising a motor, is provided with a switch or a similar means for generating a timing signal at the instant when the direction of the unidirectivity of the antenna 103 is directed to a specified azimuth say the north. Thus, a timing signal is generated from the rotation driving means 104 if and when the direction of the unidirectivity of the antenna 103 is directed to the azimuth of the north and is applied to an AND
gate 107 included in an azimuth signal circuit 105. The other input of the AND gate 107 is connected to receive the output of a pulse oscillator 106. Accordingly, the AND gate 107 provides an output of one or more pulses, if and when the an-tenna 103 for transmitting the azimuth scanning signal is brought to the specified azimuth such as the north. The pulses obtained from the AND gate 107 are applied through a power amplifier 108 to an antenna 109. The antenna 109 may be implemented by a non~directional antenna, for example, a dipole antenna. Accordingly, the transmitter portion shown in Fig. 3A
serves to transmit through the antenna 103 the azimuth scanning signal the transmitting directivity of which is in succession changeable and to transmit through the antenna 109 the azimuth associat~d information signal in the form of a pulse represent-ing when the azimuth scanning signal is directed to the specified azimuth such as the north.
Referring to Fig. 3B, a pulse oscillator ll0 is provided for normally generating a microwave pulse, for example, and the output of the pulse oscillator 110 is applied to a parallel/series converter 113. On the other hand, the parallel/
series converter 113 is supplied with the output from an error correcting and bit adding circuit 112. The error correcting L~ f~h8~3~

and bit adding circuit 112 is connected to receive a coded signal from a location data input circuit 111. The location data input eircuit 111 may, for example, comprise a key board ineluding numeral keys and function keys. Meanwhile, although the loeation data input circuit 111 may be incorporated in the transmitter, preferably the location data input cireuit 111 may be provided detaehed from the transmitter. If and when the transmitter is installed in the referenee station 1 the eireuit 111 may be provisionally provided for providing such location data, in consideration of economy in manufacture of a number of transmitters. The input cireuit 111 is used to input the location information (Xa, Ya) of the reference station 1, which is applied to the circuit 112 as the coded information.
The circuit 112 makes error eorrection to the applied coded data and adds a start bit, a stop bit and/or a parity bit. The eoded data thus processed is then applied to the parallel/series con-verter 113 in a parallel fashion. Meanwhile, it is pointed out that the eircuit 112 is not neeessarily required and henee may be omitted as desired. The parallel/series converter 113 serves to eonvert the coded signal inputted in parallel into a serial series coded signal in suecession responsive to the pulses obtained from the pulse oseillator 110, which series coded signal is then applied to a modulation circuit 115. The modulation circuit 115 serves to modulate the carrier output obtained from a carrier oscillator 114 as a function of the out-put of the circuit 113, i.e. a code signal of the data of the location (Xa, Ya). The modulated signal obtained from the modulation circuit 115 is applied through a power amplifier 116 to an antenna 117. The antenna 117 may be of a non-~8~3~ .

directivity antenna, as in case of the above described ancenna 109. Thus the antenna 117 serves to transmit with non-direct-ivity characteristic the signal as shown in Fig. 3C.
Referring to Fig. 3C, the signal 11 serves to indi-cate that the same is followed by the signal 12 which represents X, say the latitude data in terms of the specific numerical information. On the other hand, the signal 13 serves to indi-cate that the same is followed by the signal 14 which represents the data Y which is the longitude data in terms of a specific numerical value. The final signal 15 represents the termination of the data. These signals 11 ~o 15 constitute one cycle and are repeated.
Fig. 4 is a diagrammatic view showing an arrangement in an aircraft by way of an example of a moving vehicle. Typi-cally the aircraft 2 comprises a body 201, a left wing 202, a right wing 203 and a tail wing 204. A receiving and control unit 3 is provided at a given position, say the position 21 in Fig. 1, at the front end of the body 201. A receiver 4 is provided at a given position, corresponding to the position 22 in Fig. 1, of the left wing 202 of the aircraft 2. A receiver 5 is provided at a given position, corresponding to the position 23 in Fig. 1, of the right wing 203 of the aircraft 2O Furthermore, a central processing unit 6 such as a microcomputer and memories 62 and 64 operatively coupled thereto are provided in association with the receiving and control unit 3 in the aircraft 2.
As shown in Fig. 6, the microcomputer 6 comprises an input/output interface circuit 61, a read only memory 62, an arithmetic unit 63, a random access memory 64 and the like and is operated in accordance with the operation program stored in the read-only memory 62. The read-only memory 62 is also allotted to store a table of the angles ~1, 02 and 03 with respect to the time periods tl, t2 and t3 after receipt of the azimuth associated inEormation signal N representing the speci-fied azimuth until receipt of the azimuth scanning signal at the respective positions, a table representing the relation of the gradients al, a2 and a3 with respect to the angle ~, and the like. The central processing unit 6 receives the data through a data bus 327 from the receiving and control unit 3 shown in Fig. 5 and provides the operation results to a display 7, where the operation results are displayed.
Now referring to Fig. 5, the receiving and control unit 3, and the receivers 4 and 5 shown in Fig. 4 will be de-scribed in more detail. Referring to the receiver 4 provided on the left wing 202 of the aircraft 2, an electric signal re-ceived by an antenna 41 is applied through a tuner circuit 42 and an amplifier 43 to a detecting circuit 44. Similarly the receiver 5 provided on the right wing 203 of the aircraft 2 comprises an antenna 51 r a tuner circuit 52, an amplifier 53 and a detecting circuit 54. The receivingand control uni~
3 provided at the front end of the body 201 of the aircraft 2 also comprises an antenna 31, a tuner circuit 32, and amplifier 33 and a detecting circuit 34. These receivers 4 and 5 and the receiver portion including the components 31, 32, 33 and 34 of the unit 3 serve to receive the a~imuth scan-ning signal transmitted from the transmitter 100 (~igs. 3A and 3B) provided in the reference station lo The receiving and control unit 3 further comprises an antenna 301, a tuner circuit 302, an amplifier 303 and a ,' ''''''~

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detecting circuit 304 for receiving the azimuth associated information signal N. The unit 3 further comprises an antenna 305, a tuner circuit 306, an amplifier 307 and a demodulating circuit 308 for receiving the location information signal trans mitted from the reference station 1. The location information as demodulated by the demodulating circuit 308 is applied to a series/parallel converter 310. The series/parallel converter 310 serves to convert the received series data into a parallel signal as a function of the pulse from the pulse oscillator 309 and the converted parallel signal is applied to an error!parity check circuit 311.
The azimuth scanning signal as received by the re-ceiver 4 is applied to the reset input R of a flip-flop 313 included in the unit 3. Similarly, the azimuth scanning signal received by the receiver 5 is applied to the reset input R of a flip-flop 314. The output of the detecting circuit 34 included in the unit 3, i.e. the scanning signal received by the unit 3 is applied to the reset input R of a flip-flop 315. The set inputs of these flip-flops 313, 314 and 315 are connected to receive the signal obtained from the detecting circuit 304 included in the unit 3, i.e. the azimuth associated information signalO Accordingly, these flip-flops 313, 314 and 315 are set upon receipt of the azimuth associated information signal N by the receiving and control unit 3 and are reset upon 'receipt of the azimuth scanning signal by the correspcnding receiver por-tions. Accordingly, the outputs Q of these flip-flops 313, 314 and 315 remain at high level after receipt of the azimuth asso-ciated information signal N until receipt of the azimuth scan-ning signal by the respective receiver portions. The output Q

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of the flip-flop 313 is applied to an AND gate 316, the output Q of the flip-flop 314 is applied to an AND gate 317, and the output Q of the flip-flop 315 is applied to an AND gate 318.
The other inputs of these AND gates 316, 317 and 318 are con-nected in common to receive the time base signal obtained from a time base oscillator 312. Accordingly, the AND gate 316 provides the time base signal to the counter 319 during a time period when the output Q of the flip-flop 313 is at high level, i.e. after receipt of the azimuth associated information signal N until receipt of the azimuth scanning signal by the receiver

4. Similarly, the AND gate 317 provides the time base signal to the counter 320 during a time period when the output Q of the flip-flop 314 is at high level, i.e. after receipt of the azimuth associated information signal N until receipt of the azimuth scanning signal by the receiver 5. Similarly the AND gate 318 provides the time base signal to the-counter 321 during a time period when the output Q of the flip-flop 315 is at high level, i.e. after receipt of the azimuth associated information signal N until receipt of the azimuth scanning signal by the unit 3.
Accordingly, the counter 321 makes a counting operation of the time period tl shown in Fig. 2 as described previously, the counter 3I9 makes a counting operation of the time period t2 as shown in Fig. 2, and the counter 320 makes a counting operation of the time period t3 as shown in Fig. 2. The data of the time period t2 as counted by the counter 319 is stored 2~39 in a register 322. The data of the time period t3 as counted by the counter 320 is stored in a register 323. The data of thc time period tl as counted by the counter 321 is stored in a register 324.
On the other hand, the location data of -the refer-ence station 1 as error/parity checked by means of the error/
parity check circuit 311 is stored in a location data register 326. A status register 325 is further provided, so that the register 325 is loaded with a ready/busy signal obtained from the serial/parallel converter 310 and a data error signal obtained from the check circuit 311. These registers 322 and 326 transfer the data to the data bus 327 responsive to addres-sing by the decode circuit 330.
The decode circuit 330 receives an addressing signal from the central processing unit 6 shown in Fig. 6 through an address bus 328. Accordingly, the decoder circuit 330 addresses or designates any one of the registers 322 to 326 responsive to the address data obtained from the central processing unit 6. The decoder circuit 330 further receives a control signal from the central processing unit 6 through a control bus 32~. The decoder circuit 330 controls a loading, reading and other operations of the reglsters 322 to 326 respon-sive to the control signal. Thus, the data of the time periods tl, t2 and t3 and the location data of the reference~station 1 are supplied from the receiving and control unit 3 shown in Figs. 4 and 5 to the central processing unit.
The central processing unit 6 evaluates the current position and the moving direction of the aircraft 2 based on the time period data and the location data and based on the ~8~9 above described principle.
The current position and the direction of the moving aircraft 2 thus evaluated are displayed by the display 7 as shown in Figs. 7A, 7B and 7C.
The display 7 shown in Fig. 7A comprises a digital display, which receives the data concerning the X axis (the latitude) and the Y axis (the longitude) and the azimuth (~) from the input/output interface circuit 61, thereby to display the same in a digital manner.
The display 7 shown in Fig. 7B comprises a typical cathode-ray-tube display, wherein the moving locus of the aircraft is displayed on the screen 74, whereby the current position and the moving direction is indicated.
The display 7 shown in Fig. 7C comprises a pointer 75, which is driven to indicate the direction of the movement of the aircraft by the direction of the pointer 75.
Alternatively, an XY recorder and the like may be used. Alternatively, the current position and/or the moving direction may be orally announced by using a sound synthesizing apparatus.
In the foregoing description, the positons of the receiving portions on the aircraft were selected to be at the front end of the body, and at both ends of the planes. However, such positions of the receiving portions may be selected to be the front end, the central portion and the rear end of the body 201 (Fig. 4~ of the aircraft. In this latter case, by evaluating the straight line lying through these three positions on the body, the direction of the straight line formula proves to represent the direction of movement the aircraft and thus an i ' '~

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arithmetic operation of the azimuth is much simplified.
Meanwhile, although in the above described embodi-ment, the gradients al, a2 and a3 of the straight line formulas were evaluated based on the time periods tl, t2 and t3 after receipt of the azimuth associated in~ormation signal N until receipt of the azimuth scanning signal S by the respective receiver portions, alternatively the gradients may be evaluated ; based on the phase difference rather than the time difference.
; More specificalLy, the reference station 1 may be structured such that the azimuth scanning signal is transmitted in succes-sively different directions with successively different phases and the gradient a may be evaluated based on the phase differ-ences between the azimuth scanning signal as received and the azimuth associated information signal N as received by the respective receiver portions.
Although the above described embodiment was described as employing a parabola type antenna for transmitting the scanning signal in a unidirectivity characteristic, alter-natively a deflection control may be made in successively dif-ferent directions by a magnetic and electric field, withoutemploying such an antenna.
In the above described embodiments, the current position and/or the direction of the moving vehicle were evalu-ated by solving the above described simultaneous equations. In order to solve such simultaneous equations, however~ a micro-computer of a relatively high speed computing capability is required. Therefore, another principle of the present invention that can provide a practically sufficient accuracy with a simpler scheme will be described in the following.

Figs. 8A and 8B are graphs for explaining a principle of another embodiment of the present invention.
Referring to Figs. 8A and 8B, the reference numeral 1 denotes a reference station, and the reference numerals 21, 22 and 23 denote receiving positions. Let it be assumed that the angle of the respective s~raight lines connecting the each of the receiving positions 21, 22 and 23 and the reference station 1 with respect to the reference azimuth of the north is ~. Furth~r let it be assumed that among the angles, the minimum is ~min and the maximum is ~max, while the intermediate angle is ~mid.
However, if and when these angles ~ 2 and ~3 are distributed with the angle of 0 radian (= 2 ~radian) falling therebetween, let it be further assumed that 2rr is subtracted from the angle in the vicinity of 2rr radian, so that the angles are distri-buted as a positive or negative angle both in the positive and negative vicinity of 0 radian, whereupon the angles ~min, ~mid, and ~max are determined. Thus, the correlation of ~ 2 and a3 with the angles ~min, ~mid and ~max may be classified into two types, as in the case as shown in Fig. 8A and in ~he case as shown in Fig. 8B. The full relation of ~ 2 and ~3 with ~min, ~mid and ~max is shown in Table I. More specifically, in the situation as shown in Fig. 8A, the cases as identified as 1, 2 and 3 occur and in the situation as shown in Fig. 8B, the cases as identified as 4, 5 and 6 occur.

! ~

B~39 . ._ _ Table I ._ _ Allotment Illustration Case No.
~min ~mid ~max by Figures ..
1 ~1 ~3 ~2 . 2 a3 ~2 ~1 Fig. 8A

: 3 ~2 ~1 ~3 4 ~2 ~3 al ~1 ~2 ~3 Fig. 8B

: ~3 ~1 ~2 ;:-Meanwhile, the distances between the positions 21,22 and 23 are assumed to be dl = d2 = d3 = 2d, for simplicity.
The angle ~0 shown in Flgs. 8A and 8B i9 defined by the following equation (16).

= ~min + Qmax ___ _ _________ _ -----------(16) The angle ~0 may be defined as an angle with respect to a straight line connecting the location of the reference station 1 and the center of the line connecting the position of the vehicle when the maximum angle ~max is received and the position of the vehicle when the minimum angle ~min is received.
Now let it be assumed that an intersection of the straight line representing the above described angle ~0 and the straight line connecting the location of the vehicle where the minimum angle ~min is received and the position of ;

~ ~8~3~3 the vehicle where the maximum angle ~max is received is the position (Xv, Yv~ of the vehicle 2 and the distance from the position (Xv, Yv) of the vehicle to the location of the reference station l is R. Further let it be considered that the above described distance R is a straight line distance from the reference station 1 to the vehicle 2.
Furthermore, the angle ~0 shown in E'igs. 8A and 8B
may be expressed by the following equation (17) and the angle 0 shown in Figs. 8A and 8B may be expressed by the following equation (18).

= ~max~_2 ~min __~____________--------(17) ~ = ~mid - ~0 ------~-----------------(18) Furthermore, it would be appreciated that as shown in Figs. 8A and 8B the angle ~ is defined as an angle of the straight line running from the center of the straight line between the position of the vehicle where the minimum angle Omin is received and the position of the vehicle where the maxi-mum angle ~max is received to the position of the vehicle where the angle Omid is received with respect to the straight line representing the previously described angle ~0. It is pointed out that the angle ~ is defined under the convention in which the clockwise direction is a positive direction. Accordingly, the angle 9 is expressed b~ the following equation (19) in case of Fig. 8A and is expressed by the following equation (20) in case of Fig. 8B.

~7 6 + ~ ~ = 6 ~ (19) 6 ~ = ~ = 6 + ~ _____________-_----------(20) Now that the angles ~min, ~mid, ~max, ~0, ~, ~0, and ~ shown in Figs. 8A and 8B were defined as described in the foregoing, now an actual arithmetic operation will be described in the following. Now let it be assumed that the straight line distance R from the location of the reference station 1 to the position of the vehicle 2 is large as compared with the distance 2d between the respective receiving positions.
Accordingly, it is assumed that the angles ~ and ~0 shown in Figs. 8A and 8B and also shown in the above described equations (17) and (18) are small.
Accordingly, in case of Fig. 8A the following equa-tion (21) is obtained, while in case of Fig. 8B the following equation (22) is obtained.
R sin(-~ d sin(~ (21) R sin(-~ d sin(~ ~ 0) --------------(22) Furthermore, in case of Fig. 8A, the following equa-tion (23) is obtained, while in case of Fig. 8B, the following equation (24) is obtained.
R sin~0 -~ d cos~ + ~ -----(23~
R sin~0 - d cos(-~ -----------(24) Accordingly, by dividing the equation (21) by the equation (23) and by dividing the equation (223 by the equation (24), respectively, the angle ~ for each of the cases shown in Figs. 8A and 8B is obtained by the following equations (25) and 3~

(26), respectively.

~ ` t n~l( 1 ~r~ - tan ~ 0)~~ --(25) ,i sin~ ) + ~ - tan 1(~ ~0 ) + ~ (26) Now using the angle ~ expressed by the equations (25) and (26), the azimuth ~ of the vehicle 2 is evaluated. The azimuth ~ of the vehicle 2 may be evaluated in the manner shown in Table II for each of the cases 1 to 6 in terms of the previously depicted Table I.

Table II
.~
Case No. How to Evaluate ~
~ ..
1 .~ o + ~

2 ~ + ~ + 3 3 ~ o + ~ - ~3 4 ~ = ~ + ~

~ = ~ + ~ + ~3 6 ~ = ~0 + ~ _ 3 , _ _ .. _ ~ _ , .

The current position (Xv, Yv) of the vehicle 2 may be expressed by the following equations (27) and (28).

23~

Xv = Xa + R sin~0 --------------------(27) Yv = Ya + R cos~0 -------- -------- --(28) wherein the straight line distance from the location of the reference station 1 to the position of the vehicle 2 is expressed by the equation (29) in case of Fig. 8A and is expressed by the equation (30) in case of Fig. 8B.

d cos(~ + ~) R = sin~0 -------------- - ------(29) d cos(~
R = sin~0 -----------------------(30) Fig. 9 is a f low diagram showing the steps of an arith-metic operation based on the above described simplified method.
As is understood from the Fig. 9 flow diagram and the foregoing description, the simplified method contains a very simplified computation steps as compared with the previously described method for solving the simultaneous equations and thus enables high speed computation. Thus, this approach enables employment of even a microcomputer of a relatively slow computation speed.

Nevertheless, this approach achieves sufficient accuracy for most purposes.
~ ig. 10 is a diagrammatic view for explaining the princi-ple of another embodiment the present invention. In the embodiment shown, the vehicle is provided with only one receiving and control unit which may be the same as that shown in Fig. 5.
According to the embodiment shown, three pieces of data are utilized that are obtained at thr e successively different positions 2, 2' and 2'' of the vehicle when the vehicle - moves in the service area of the reference station 1.

8~23~

With respect to these successive positions 2, 2', and 2'' of the vehicle, the time periods tl, t2, and t3 from receipt of the azimuth associated information signal N until receipt Of the aæimuth scannin~ signal S at the respective positions 2, 2', and 2'', respectively, are evaluated. The previously described simultaneous equations (1) to (15) are thus solved, whereby the position data (Xl, Yl), (X2, Y2), and (X3, Y3) of the vehicle at each of the positions 2, 2' and 2'' is evaluated.
The moving direction or azimuth of the vehicle 2 can be known 1~ by the gradient of the straight line connecting between the posi-tions (Xl, Yl) and (X2, Y2), the gradient of the straight line connecting between the positions (X2, Y2) and (X3, Y3) and the like.
As understood from the above described embodiment, the vehicle 2 may be provided with only at least one receiving and control unit.
Fig. 11 is a diagrammatic view for explanation of a fur-ther embodiment of the present invention. The Fig. 11 embodiment employes/ as a vehicle, an automobile 8 which moves on the road.
The reference station 1' is provided in the vicinity of an inter-section, for exampleO Such receivers as shown in Fig. 5 are pro-vided at the positions 81, 82, and 83 of the awtomobile 8.
Alternatively/ the Fig. 11 embodiment may be structured such that a receiving and control unit 3 is provided only at one position 81 of the automobile 8, while fixed receiving stations are provided at the locations 82' and 83' in the vici-nity of the intersection, so that the data as received by the fixed receiving stations is received by the receiving and control unit borne on the automobile 8 at the position 81 to obtain the above described time periods tl, t2 and t3. In this case, since the position 82 (X2', Y2',) and the positions 33' (X3', Y3') are known quantities, the arithmetic operation steps can be more simplified.
The above described approach, wherein only one receiving and control unit is provided on the vehicle while the fixed receiving stations are separately provided and the data concern-ing the time is transmitted from the fixed receiving stations to the receiving and control unit borne on the vehicle, whereby the current position of the vehicle is evaluated, can be equally applied to any types of vehicles such as an aircraft, ship and the like other than an automobile. It is further pointed out that by way of a modification of the above described embodiment only one fixed receiving station may be provided, while a receiver and a receiving and control unit may be provided on the vehicle.
Figs. 12A and 12B are views for explaining the principle of a still further embodiment of the present invention. In the embodiment shown, two unidirectional directivity antennas 103 and 103' are employed in order to transmit the azimuth scanning signal. A rotational driving circuit 104 is provided with a rotational direction switching circuit 104b. The rotational direction switching circuit 104b is aimed to control rotating means 103a and 103a' ~or antennas 103 and 103', respectively.
The rotating means 103a and 103a' are structured to provide a signal representing that the antennas 103 and 103' are directed to a predetermined azimuth such as the north at such timing. The north representing signals are applied to the con-trol circuit 104a. The control circuit 104a is structured such ~8'~3~

that, if and when one antenna 103 is rotated by one rotation from the predetermined azimuth such as the north to be again directed to the north, for example, the control circuit 104a switches the other antenna 103' to be rotated contrary to the rotating direction of the above described antenna 103. Accordingly, the antennas 103 and 103' transmit the azimuth scanning signal S
of one cycle, as shown in Fig. 12B. The azimuth scanning signal S is transmitted from the antenna 103, while the azimuth scann-ing signal S' is transmitted from the antenna 103' which rotates in the reverse direction. The azimuth scanning signal S
in the following cycle is transmitted at a predetermined time separation from the azimuth scanning signal S' of the preceding cycle. More specifically, in the Fig. 12A embodiment, it follows that the azimuth scanning signals S and S' are trans-mitted alternately and intermittently for each cycle. As to be described subsequently, in determining the azimuth, such determination is necessarily made by a combination of the azimuth scanning signals S and S', thereby to avoid such determination based on the preceding scanning signal S' and the current scanning signal S.
According to the embodiment shown in Figs. 12A and 12B, the angle ~1 (and ~2 and ~3) is known in the manner depicted in Fig. 13, for example. More specifically, let it be assumed that the azimuth scanning signal is transmitted in the arrow direction by means of the antenna 103, for example, from the reference station 1, whereupon the azimuth scanning signal is transmitted in the arrow B direction by means of the antenna 103' from the reference station 1. In such a situation, the vehicle 2 receives the azimuth scanning signal at the time ta and then ~823~

receives the azimuth scanning signal at the time tb. Accord-ingly, the vehicle 2 can determine the angle ~1 (and ~2 and ~3) based on the time period from the time ta when the first scann-ing signal S is received to the time tb when the scanning signal S' is received. The azimuth signal circuit portion 105 de-scribed with reference to Fig. 3A is not required in the embodiment depicted in conjunction with Figs. 12A, 12B and 13.
Since the azimuth scanning signal is reversed for each cycle, it follows that the reversing timing represents the particular azimuth such as the north, which means that the azimuth scanning signal per se contains the information concerning the predeter-mined azimuth such as the north.
It is pointed out that light, sound wave, ultrasonic wave and the like can be equally employed, apart from electric wave, for the purpose of transmission of the signals, in practicing the present invention. In employing light, it is preferred to utilize a very sharp light beam and in this context a laser beam can be advantageously utilized. When a sound wave or ultrasonic wave is employed, the current position and the moving direction of a vehicle moving in the air, on the ground, in the water or under the sea can be measured.
In case where a vehicle is an aircraft, the movement of the aircraft can be measured in terms of three dimensions by employing the data of various aircraft measuring equipment such as an altimeter.
If a vehicle is of a type which can assume a variably inclined attitude with respect to the ground, such as an air-plane, it is necessary to correct the coordinate data in accordance with the inclination of the vehicle. If a vehicle 3~

is of a type that can assume a varying height or depth from the reference level, it is also necessary to correct the coordinate data. For example, considering an airplane flying at the height h with the direct distance between the reference station and the airplane being ~, then it is necessary to evaluate the horizontal distance ~hr between the reference station and the airplane as the coordinate data. To that end, the formula ~hr = ~ 2 _ h2 may be operated by the use of a microprocessor. In the case of an airplane wherein three receiving stations are disposed along a straight line in the airplane, similar correction is required in accordance ~ith the pitching angle of the airplane.
Although in the foregoing embo~iments the linear equations were utilized, any other equations such as those for hyperbola can be utilized for the purpose of the present inven-tion. It is further pointed out that in indicating the current position of a vehicle, not only an ordinate representation as shown in Fig. 7A but also a polar representation may be utilized.
Fig. 14 is a view for explaining the principle of a further embodiment of the present invention. The Fig. 1~
embodiment is a compact implementation of the system in a port-able type that can be borne in any type of vehicle. The embodi-ment is adapted to effectively prevent the data from being erroneously displayed when the vehicle is in an oblique attitude. To that end, a casing 20 is provided with a level 9 in the center serving as an attitude angle detecting means. The level 9 serves to detect whether the vehicle per se and thus the casing 20 is in a horizontal state or not, as to be more fully described subsequently. The casing 20 is further provided with at least three extendable/retractable members 210, 220 and 230 provided to extend in different directions with the angle of 120, for example, therebetween, with the level 9 positioned at the center thereof. These members 210, 220 and 230 are provide~
with receiving means supporting members 211, 221 and 231 for fixing receivers at the respective tip ends, respectively. The receivers 3, 4 and 5 described previously in conjunction with Fig. 5 are provided at the respective receiving means supporting members 211, 221 and 231, respectively. The extendable/
retractablelmembers 210, 220 and 230 are provided with coeffi-cient generators, now shown, for detecting the extended or retracted condition of the respective receiving means supporting members 211, 221 and 231 and for generating the respective coefficients associated with the positions (Xl, Yl), (X2, Y2) and (X3, Y3) of the receiving means supporting members 2 1, 221 and 231, respectively. More specifically, the coefficient generator installed in the member 210 is adapted to generate the coefficient (xl, yl) representing the ratio of the extended position value with respect to a reference value when the member 211 is wholly retracted. Likewise, the coefficient generators installed in the members 220 and 230 are adapted to generate the respective coefficients (x2, y2) and (x3, y3). When not in use, for example, for transport to a new site, members 210, 220 and 230 are retracted to make the system compact, but are extended when the system is in use.
Figs. 15A and 15B are views showing one example of a level employed in the Fig. 14 embodiment, wherein E`ig. 15A shows a plan view of the level and Fig. 15B is a sectional view of the Fig. 15A level taken along the line XVB-XVB. The level 9 shown 32~

in Figs. 15A and 15B is aimed to detect the horizontal state of the intersecting two directions and comprises a hollow disc type container 91, a mercury 92, and four contacts 93, 94, 95 and 96 provided on the inner peripheral wall of the container 91 so as to be opposed to each other. The level 9 of such structure can detect a non-horizontal state of a ship, for exam-ple, when the ship is in an oblique state and any one of the contacts 93 to 96 is in contact with the mercury 92. Meanwhile, in detecting the horizontal state, the allowable errors of the current position or the direction evaluated by the operation may be taken into consideration from the practi~al standpoint.
To that end, an allowable range may be determined in the hori-zontal detected output from the level 9 so that the horizontal state is deemed as established within a predetermined range even if the level 9 has not completely reached the horizontal state. The horizontal detecting means is not limited to such level 9 as shown in Fig. 15 but any other type of levels such as that utilizing a pendulum, a gyroscope, or the like may - -be utilized.
Fig. 15 is a block diagram of still a further embodiment of the present invention. A central processing unit 6 may be t~ -same as that shown in Fig. 6. The central processing unit 6 is supplied with the output signals from the coefficient genera-tors 212, 222 and 232 provided in the members 210, 220 and 230, respectively, shown in Fig. 14. The central processing unit 6 is also supplied with the detected signals from the con-tacts 93 to 96 of the level 9 shown in Fig. 15 through the OR
gate 65.
Now referring to Figs. 14 to 16, the operation of the embodiment shown will be described. The casing 20 is borne ~--J
~. ~

3~

on a vehicle such as a ship, an automobile or the like. For use the members 210, 220 and 230 are extended. Then the co-efficients (~1, yl), (x2, y2) and (x3, y3) associated with the lengths of the respective extended members 210, 220 and 230, are generated from the coefficient generators 212, 222 and 232, respectively~ The receivers 3, 4 and S receive signals in the same manner as described previously. The central processing unit 6 evaluates the current position and/or moving direction based on the scanning signal, the position information and the direction associated information signal as received and in accordance with the above described arithmetical formula. In the arithmetical operation, ~1, Yl, X2, Y2, X3, and Y3 in the above described equations (4) to (15) are corrected to (Xl +
xl), (Yl ~ yl), (X2 + x2), (Y2 + y2), (X3 + x3), and (Y3 + y3), respectively, in accordance with the generated coefficients.
The current position and the direction of movement of the vehicle thus evaluated are displayed by the display portion 7. If and when the vehicle is inclined in any direction, the mercury 92 of the level 9 comes to be in contact with any one 2~ of the contacts 93 to 96, Then the detected signal representing the vehicle being not in a horizontal state is obtained from the corresponding contact and is applied through the OR gate 65 to the central processing unit 6. Accordingly, a display inhibiting signal is applied to the display portion 7~, whereby display of the operation result is inhibited. Accordingly, the display portion 7 displays the current position and the moving direction only if and when the vehicle is in the hori~on-tal state, Since the current position and the direction of movement are displayed only when the level 9 detects the horizontal state of the vehicle, erroneous data due to a distance differ-ence between the reference station 1 and the respective receivers caused by inclination of the vehicle, such as rolling or pitch-ing of the vehlcle, can be prevented from being displayed.
Furthermore, since the receivers are provided at the tip end portions of the members 210, 220 and 230, the system can be made compact in carrying the same by retracting the members 210, 220 and 230. In the case where the system is borne on a ship, for example, the distances dl, d2 and d3 can be made maximum by extending members 210, 220 and 230 to the greatest possible extent. As a result, the differences between the gradients ~ 2 and ~3 of the linear equations of the lines connecting the respective receivers 3, 4 and 5 are maximum and therefore the linear equations are well apart from each other and measurement of the current position and/or the direction of movement is most accurate.
In the case of the above described embodiment, three receivers 3, 4 and 5 may be provided for each of members 210, 220 and 230. Alternatively only one member may be provided so that only one receiver may be located thereon, while the remaining two receivers may be supported on the casing.
Fig. 17A ls a view showing still a further embodiment of the present invention. The Fig. 17A embodiment i5 of a portable type and may be borne on a bicycle, motorcycle or the like for the-purpose of measurement of the current position and the direction of movement. A casing 271 is provided with rod-like extendable/retractable members 272 and 273 which are extendable and retractable in opposite directions. Receiver 23~

supporting means 274 and 275 are provided at the respective tip end portions of members 272 and 273. The receivers 4 and 5 such as described previously in conjunction with Fig. 5 are provided at the respective receiver supporting mea~s 27-~ and 275, respect-ively. Accordingly, by extending or retracting the members 272 and 273, the receivers 4 and 5 are displaceable. The receiving and control unit 3 shown in Fig. 5 is provided in the upper position 276 of the casing 271. The level 9 is provided on the upper portion of the casing 271 for detecting the horizontal state of the extending direction of the members 272 and 273.
The display 7 and the central processing unit 6 are installed in the casing 271. Since the system is portable and the receiving positions of the receivers 4 and 5 for receiving the electric wave from the reference station 1 are displaceably provided, the system is easy to carry and the position and/or the direction of movement can be measured with simplicity and ease by installing the system on a motorcycle, bicycle or the like.
Fig. 17B is a view showing still a further embodiment of the present invention. Fig. 17B is similar to Fig. 17~ but shows a modified embodiment wherein tape-like extendable and retractable members 282 and 283 are employed in place of the telescopic members 272 and 273 of the Fig. 17A embodiment. More specifically, the metallic tape expansible/contractible members 282 and 283 are yieldably wound in the casing 281. In actual measurement, the members 282 and 283 are yieldably unwound from the casing 281 in order to increase the distances between the respective receivers.
Figs. 18A, 18B and 18C are views for explaining the principle of still a further embodiment of the present invention.

,, ~., The embodiment shown in Figs. 18A, 18B and 18C is aimed to evaluate the position and/or the direction of movement in accordance with simpler arithmetic formulas using the portable type system shown in Fig. 17A or 17B. First, in the same manner as that described in conjunction with Fig. 1, the time periods tl, t2 and t3 after receipt of the signal N representing the particular direction until receipt of the scanning signals S, S' and S", respectively, are obtained. The angles of the receiving points 211, 221 and 231 with respect to the reference station 1 are evaluated from the time periods tl, t2 and t3 and the rotation speed of the scanning signal S. Assuming that these angles are ~ 2 and 03, respectively, the angles 2 and ~3 may be expressed by the following equations (33), t34) and (35), respectively.
~1 wtl (33) ~2 = wt2 - - (34 93 = wt3 By using these angles and the lengths dl, d2 and d3 connecting the respective positions 211, 221 and 231, the distances between the reference station 1 and the respective receiving points can be evaluated in the following manner. More specifically, in general, the three receiving points 211, 221 and 231 can be deemed as lying on one vehicle. Therefore, let it be assumed that the center P of the triangle defined by the respective sides dl, d2 and d3 be considered as a point repre-senting the current position of the vehicle. Assuming that the inner angles of the triangles be 2 ~, 2 ~and 2 ~, then ~, ~ and r can be evaluated by the following equations (36), (37) and (38).

~8f~3~

= ~ cos 1 _ d2 - (dl + d3 ) ~ --(36) = ~ cos 1 _ d3 -2dd ~ d2 ) ______-----(37) = ~ cos 1 _ dl -2d2dd3 ~~ d3 ) ________ ---(38) Assuming that the distances from the apices of the triangle to the center P be el, e2 and e3, then el, e2 and e3 can be evaluated by the following equations (39), (40) and (41).

el = sin_ ~ _ dl -------- -----------___(39) e2 = sin ~ dl -----------------------e3 = sin ~ _ d3 ------~----------------(41 sin ( ~
. -Now referring to Fig. 18B, let it be assumed that theline connecting the reference station 1 and the center P is R, the angle of the line ~ connecting tha reference s$ation 1 and the position 211 with respect to the line R is ~, the angle of the line ~ with respect to the line dl connecting the positions 211 and 221 is x, the angle between the line ~ connecting the reference station 1 and the position 221 and the line d2 connect-ting the positions 221 and 231 is y, and the angle between the line ~ connecting the reference station 1 and the position 231 and the line d3 connecting the positions 231 and 211 is z.
Further the following equations are assumed.

-- ~0 --32~3~

~, ~ 2 -- (42) ~ 3 -- (43) I'hen by the sine theoreml the following equations are obtained.
el sin ( ~-x- ~) = R sinO for ~OlP ------l44) e2 sin (y~ = R sin(~ -~) for AO2P ------(45) e3 sin (z+ ~- ~) = R sin( -~) for ~03P ------(46) where y = x - ~ + ~ - 2 ~ -----------------------------(47) z = x - ~ + ~ + 2 ~ _______________--------------(48) By substituting the equations (47) and (48) in the equations (44) and (46), the following equations are obtained.
kl sinx + ml cosx - R sin~ -----------------------(49) k2 sinx + m2 cosx = R sin ~ cosO - R cos ~ sin~ --(50) k3 sinx + m3 cosx = R sin cos~ - R cos sin~ --(51) where kl = el cos ~ , ml = el sin ~
k2 = e2 cos( ~ + ~ ), m2 = -e2 sin( ~ + ~ ) k3 = e3 cos( ~ 2~ - ~), m3 = -e3 sin(~ - 2~

By multiplying the above described equation (50) by sin ~ , and by multiplying the equation (51) by sin ~ and by making subtraction, the following equation is obtained.
sin ~(k2 sinx + m2 C09X) - sin ~ (k3 sinx + m3 cosx) - R sinO(sin ~ cos ~ - cos ~sin ~) -----------------~----(52) By substituting the equation (49) in the right side of ~he equation (52), the followlng equation is obtained.
ml sin( - ~ ) + m2 sin - m3 sin ~
tanx kl sin(~ -~~~) + k2 sin ~---k3 sin ~ (53) , z~

x can be obtained from the equation (53) and, by consid-ering the definition of x, 0 < x ~ when ~ 2 ----------------------(54) < x ~ 2~ when ~1 C ~2 -------------------(55) From the equations (53), (54) and (55), sin x and cos x can be obtained.
Now from the equation (50), the following equation is obtained.
R sin ~ cos~ = k2 sinx + m2 cosx + cos ~ (k2 sinx + ml cosx) (56) Therefore, from the equations (56) and (49) the following equation (57) is obtained. ;
sin ~(kl sinx + ml cosx) tan~ = (k2 +-kl cos ~) sinx + (m2 +~ml cos~~) cosx (57) where usually ~ is defined as 1~1 - ~. The case where the reference station 1 is within a circle the diameter of which is commensurate with the line connecting the center P and the position 211, that is, 1~1 ~ ~2' could extremely seldom occur.
Since x and ~ can be determined from the above described equations (53) and (57), the distance between the reference station 1 and the center P of the triangle can be obtained from the equations (49), (50) and (51). More specifically, kl sinx + ml cosx R = sin~ __________ _-_-----------(58) or R k2 sinx + m2 cosx _________________________ or - k3 sinx ~ m3 cosx R = sin(~ - ~) ___________--------------(60) . . .j 8~39 Accordingly, the coordinate (X, Y) of the center P may be expressed by the following equations (61) and (62).
X = Xa + R sin(~l - ~) -------------------(61) Y = Ya ~ R cos(~ ) -------------------(62) Now assuming that the vehicle is moving in the direction connecting the center P and the position 221, then as is clear ~rom Fig. l~C, ~1 + ~ - x - ~ represented by the following equation (63) can be obtained.

(01 - ~) + (0 + ~ - x - ~ 1 + ~ - x - ~ -(63) Meanwhile, although in the above described embodiment the respective positions 211, 221 and 231 were selected to be the positions of the apices of the triangle, such should not be construed by way of limitation and alternatively the positions 211, 221 and 231 may be disposed on a straight line. In the latter mentioned case, the angles of the above described triang e may be selected such that ~ = y = 0 and ~ = ~2 and in addition the lengths of the sides may be selected such that el = dl, e3 =
d2 and e2 = 0 and therefore the center P comes to be consistent with the position 221. Accordingly, the distance from the refer-ence station 1 to the center P, i.e. the distance R to the position 221 and the direction can be obtained with extreme simplicity using only the required equations among the previous~st described arithmetic formulae.
Figs. 19 and 20 are views for explaining the principle of still a further embodiment of the present invention. Parti-cularly, Figs. 19 and 20 show an aircraft serving as a vehicle in an attitude wherein the lines connecting the respective receivers are not in horizontal due to pitching and rolling, in which case the distances between the respective receivers need - ~3 -3~

be corrected. More specifically, Fig. 19 shows an embodiment in which the receivers 3, 4 and 5 shown in Fig. 5 are provided at the positions of the front end portlon, the central portion and the rear end portion of the aircraft 2. The distance between the positions 241 and 242 is assumed to be d4 and the distance between the positions 242 and 243 is assumed to be d5. Assuming that the angle of elevation of the aircraft 2 is 7, then the effective length D4 in the horizontal direction between the positions 241 and 242 and the effective length D5 in the horizontal direction between the positions 242 and 243 may be expressed by the following equations (64) and (65).
D4 = d4 cos ~ -------------(64) D5 = d5 cos ~ _~____________-----------(65) ; Accordingly, the effective lengths D4 and D5 in the horizontal direction between the respective receivers 3, 4 and

5 are obtained based on the above described equations (64) and (65). The thus obtained effective lengths D4 and D5 are substituted for dl and d2 in the above described equations (36), (37) and (38) and d3 = 0 is substituted. Since the respective receivers 3, 4 and 5 are disposed on a straight line, it is assumed that ~ = ~ = 0 and ~ = 7~. By making calculation using the above described equations (31) to (63), the distances between the respective positions 211, 221 and 231 where the three receivers 3, 4 and 5 are disposed are corrected and as a result the current position and/or the moving direction of the vehicle can be obtained with accuracy.
Referring to Fig. 20, one receiver is provided at the position approximately of the center of the body of the aircraft 2 and the remaining receivers are provided at the ~7 positions 272 and 273 of the ends of the main wings. It is assumed that the distance between the positions 271 and 272 is d6 and the distance between the positions 271 and 273 is d7. Assuming that the rolling angle or the angle of bank of the aircraft ? is ~ , the effective lengths D6 and D7 in the horizontal direction between the positions 271 and 272 and between the positions 271 and 273 may be expressed by the following equations (66) and (67).
D6 = d6 cos ~ ------(66) D7 = d7 cos ~ ---------- ------------------(67) By calculating the above described e~uations (66) and (67), the effective lengths in the horizontal direction between the respective positions can be obtained. In the same manner as that of the previously described calculation in conjunction with Fig. 19, the distances between the reference station 1 and the respective positions 271, 272 and 273 are corrected based on the effective lengths in the horizontal direction. As a result, the position and/or the direction of movement of the aircraft 2 can be obtained with more accuracy.
Fig. 21 is a block diagram of the embodiment shown in Figs. 19 and 20. The central processing unit 6 may be the same as that described previously in conjunction with Fig. 6 and the central processing unit 6 is supplied with information concern-ing the distances d4 and d5 shown in Fig. 19 and information concerning the distances d6 and d7 shown in Fig. 20. The aircraft 2 is provided with detectors 281 and 2~2 for detecting the angle of elevation ~ and the angle of rolling or bank ~ , respectively, and the detected signals from these detectors are applied to the central processing unit 6. The central processing ",,t~8~

unit 6 makes arithmetic operation based on the previously described equations (64) to (67) to evaluate the effective len~ths in the horizontal direction.
Figs. 22 to 26B are views showing still a further embodiment of the present invention. The embodiment shown is adapted to enable measurement of the position and/or the direction of movement of the vehicle without being influenced by an obstacle even when the electric wave transmitted from the reference station is interrupted by the obstacle while the vehicle is moving receiving the electric wave transmitted from the reference station. To that end, a plurality of reference stations are provided at a plurality of different predetermined fixed positions. Preferably, only the electric waves received from any of these reference stations without being influenced by any obstacle are used to obtain desired data by evaluating the mean value of the data contained in these electric waves, thereby to measure the position and/or the direction of movement of the vehicle based on the mean value of the received electric waves.
Now referring to Fig. 22, the embodiment shown comprises three reference stations la, lb and lc provided at three differ-ent predetermined fixed positions (Xa, Ya), (Xb, Yb) and (Xc, Yc) disposed in the vicinity of the moving path of the vehicle in the same plane where the vehicle moves. Substantially the same transmitters, 100', 100'' and 100" ' as the transmitter 100 previously described in conjunction with Figs. 3A and 3~ are provided at these reference stations la, lb and lc~ respectively.
These transmitters 100', 100'~ and 100''' are adapted to transmit a sequential scanning signal, an azimuth associated information signal and a position associated information signal, as shown in Fig. 24, on a time shariny basis by means of a time sharing circuit 121. More specifically, the transmitters 100', 100'' and 100''' are adapted to transmit in succession the electric waves at the respec-tive times a', a'' and a''', respectively.
On the other hand, an automobile 26 has the receivers 3, ~ and 5 of substantially the same type as previously described in conjunction with Fig. 5 borne at a position 261 at the front end of the automobile 26, at a position 262 at the right side of the automobile 26 spaced apart from the position 261 by a distance dl, and at a position 263 a-t the left side spaced apart from the pOSitiOII 262 by a distance d2, the positions 261 and 263 being spaced apart from each other by a distance d3. The respective receivers 3, 4 and 5 provided at these positions 261, 262 and 263 are structured to be capable of receiving the above described electric waves of any of the above described reference stations la, lb and lc when the automobile 26 enters in a service area of any of the above described reference stations la, lb and lc.
Figs. 25A and 25B are block diagrams of the receiving means borne in the vehicle shown in Fig. 22. First referring to Fig. 25A, a receiving apparatus 350 comprises a receiving and control unit 3, and receivers 4 and 5 previously described in conjunction with Fig. 5. An antenna 351 comprises the antennas 31, 301, 305, 41 and 51 previously described in con-junction with Fig. 5. The receiving apparatus 350 receives the electric waves transmitted on a time sharing basis from the three transmitters 100', 100;' and 100''' previously described in conjunction with Fig. 23. The received signals received at the times a', a'' and a''' by the receiving apparatus 350 are applied to a demultiplexer 352 and a timer ~8~3~

circuit 353. The timer circuit 353 generates a predetermined timing or synchronizing signals in response to and in synchronism with the signals received at the times a', a'' and a" ' respectively, shown in Fiy. 24. The synchronizing signals are applied to the demultiplexer 352 as switching signals. The demultiplexer 352 is responsive to the switching signals to sequentially switch the received signals received at the times a', a'' and a'''. The output signals of the demultiple~er 352 are applied to a level detecting circuit 354 and a selecting circuit 360. The level detecting circuit 354 is adapted to temporarily store the signals at the times a', a'' and a'' outputted from the demultiplexer 352. The level detecting circuit 354 is further adapted to determine the received signal of the highest signal level, for example the received signal at the time a', to provide a selecting signal for selecting the received signal of the highest level to the selecting circuit 360. The selecting circuit 360 is responsive to the selecting signal obtained from the level detecting circuit 354 to provide the received signal of the highest signal level, such as the received signal of the timing a', to the central processing unit 6.
Now referring to Figs. 22 to 25A, the operation of the embodiment will be described. As the automobile 26 moves along the moving path, the receiving apparatus 350 receives~the elec-tric waves transmitted from any of the reference stations la, lb and lc. In the absence of any obstacles such as 16, 17 and 18 along the moving path of the vehicle, the receiving apparatus 350 receives in sequence the electric waves transmitted from the three reference stations la, lb and lc at the times a', , ~8Z3~

a'' and a''', respectively. The signals received by the receiving apparatus 350 are switched or demultiplexed by the demultiplexer 352 as a function of the synchronizing signals or the timing signals generated by the timer circuit 353. The level detecting circuit 354 compares the signal levels of the received signals at the times a', a'' and a''', to cause the selecting circuit 360 to select the signal of the highest signal level. Assuming tha~ the automobile 26 is closest to the reference station la, then the received signal at the time a' transmitted from the reference station la is selected. The received signal selected by the selecting circuit 360 is applied to the central processing unit 6.
The central processing unit 6 is responsive to a scanning signal, an azimuth associated information signal, and a position associated information signal included in the recelved signal thus applied to the central processing unit 6 to evaluate the position and/or the direction of movement of the vehicle in accordance with the previously described computation formula.
Now assuming that the automobile 26 moves to reach a position as shown in Fig. 22, for example, then the electric waves transmitted from the reference stations la and lc are interrupted by obstacles 17 and 18. Therefore, the electric waves at the times a' and a''' become small and can be hardly received by the receiving apparatus 350. On the other hand, since there is no obstacle between the automobile 26 and the reference station lb, the electric wave at the time a'' trans-mitted from the reference station lb can be received by the receiving apparatus 350 with a large signal level. The level detecting circuit 354 determines that the signal of the timing 2~9 a'' transmitted from the reference station lb to be of the maximum signal level, thereby to cause the selecting circuit 360 to select the received signal at the time a''. Then the received signal at -the time a'' is applied from the selecting circuit 360 to the central processing unit 6. Accordingly, the central processing uni-t 6 is responsive to -the received signal at the a" to evaluate the current position and/or the moving direction of the vehicle.
In such a situation, it could occur that the electric wave transmitted from the reference station la reaches the automobile 26 as a reflected wave reflected by an obstacle 16.
However, since such reflected wave is likely to be attenuated, such electric wave transmitted from the reference station la and reflected by the obstacle 16 is received by the receiving apparatus 350 with a signal level smaller than that of the electric wave transmitted from the reference station lb and as a result such reflected electric wave is not selected by the selecting circuit 360.
Fig. 25B is a block diagram of a modification of the Fig. 25A embodiment. The Fig. 25B embodiment is structured to measure the current position and/or the moving direction of the vehicle by evaluating the mean values of the data in the respec-tive received signals transmitted from a plurality of reference stations referring-to Fig. 25B, the receiving apparatus 350, the demultiplexer 352 and the timer circuit 353 may be the same as those shown in the Fig. 25A embodiment. The output signals of the demultiplexer 352 are applied to gate circuits 355 to 357 and a level detecting circuit 358. The level detecting circuit 358 is structured to determine individually whether each of the received signals fed from the demultiplexer 352 exceeds 3~

a predetermined level. The above described predetermined detecting level is selected such that only the electric wave directly reaching the automobile 26 from the reference stations la, lb and lc without being interrupted by any obstacles 16, 17 and 18 can be level detected to provide the individual output from the level detecting circuit 358.
The individual level detected outputs from the level detected circuit 358 are individually applied to the correspond-ing gate circuit 355, 356 and 357 of the respective received signals. Accordingly, the gate circuits 355, 356 and 357 serve to provide the received signals having a signal level larger than the predetermined detecting level to the central processing unit 6. The central processing unit 6 is responsive to the said signals to evaluate the current position and/or the moving direction separately with respect to each of the received signals if and when two or more signals are received. Since such plurality of pieces of information thus evaluated concerning the current position and/or the moving direction of the vehicle based on a plurality of received signals could be inconsistent with each other due to errors, the above described plurality of pieces of information concerning the position and/or the direction of movement of the vehicle are applied to an averaging circuit 359. The averaging circuit 359 is structured to evaluate a mean value of the above described plurality of pieces of information. Since such averaging circuit 359 is well-known to those skilled in the art~ it is not beli~ved necessary to describe the same in more detail. The mean value output is displayed by the display shown in Fig. 7.
The embodiments shown in Figs. 25A and 25B were struc-tured to generate a switching signal to the demultiplexer 352 by ~ 3~

means oE the timer circuit 353 for the purpose of demultiplexing the electric waves transmitted from the reference stations la, lb and lc on a time sharing basis in a synchronized manner with the time sharing transmission. Alternatively, the system may be adapted such that a code signal identifying the respective reference station is included in the respective electric wave transmitted from each of the reference stations la to lc and such identifying code signal is also received in sequence by the receiving apparatus 350 and is decoded, so that the decoded signal is used to drive the demultiplexer 352.
In place of transmitting the electric waves from the respective reference stations on a time sharing basis, the electric waves may be simultaneously transmitted by respective reference sta~ion in the form of modulated wave signals using a plurality of carrier waves of different carrier frequencies.
Figs. 26A and 26B are block diagrams of receiving means for receiving the electric waves transmitted as modulated wave signals from the reference stations using three carrier waves of different carrier frequencies. The Fig. 26A embodiment comprises three receiving apparatuses 350, 370 and 380 each of which corresponds to the receiving apparatus 350 of the Fig.
25A embodiment. These receiving apparatuses 350, 370 and 380 each comprise tuning circuits tuned to the frequencies of the electric waves transmitted from the reference stations la, lb and lc, respectivelyO The received signals of the respective receiving apparatuses 350, 370 and 38~ are applied to a level detecting circuit 354. The level detecting circuit 354 may be substantially the same as the level detecting circuit 354 in , the Fig. 25A embodiment and serves to determine the received ~8~3~

signal of the highest siynal level among the respective received signals, thereby to cause the selecting circuit 360 to select the received signal of the highest signal level. Therefore, according to the Fig. 26A embodiment as well, even if electric waves transmitted from different stations such as la and lc are interrupted by an obstacle as shown in Fig. 22, still the electric wave transmitted from the reference station lb is received and the current position and/or the moving direction can be evaluated.
Fig. 26B is a modification of the Fig. 26A embodiment and corresponds to the Fig. 25B modification of the Fig. 25A
embodiment. More specifically, the Fig. 26B embodiment also comprises three receiving apparatuses 350, 370 and 380 as in the case of the Fig~ 26A embodiment. The received signals of the respective receiving apparatuses are applied to the gate circuits 355, 356 and 357 and the level detecting circuit 358.
The level detecting circuit 358 is structured to individually level detect the respective received signals to individually determine whether the signal level of each of the signals exceeds a predetermined level. The level detecting circuit 358 serves to individually enable the gate circuits corresponding to the received signals having signal levels exceeding the predetermine signal level. As a result, the central processing unit 6 receives only the signals having a large signal level directly reaching from the reference stations to the automobile 26 without being interrupted by any obstacles 16, 17 and 18O The central processing unit 6 is responsive to the received signal or signals to evaluate information concerning the current posi-tion and~or the moving direction of t~e vehicle in the previousl~r described manner. The averaging circuit 359 is provided to evaluate the mean value of a plurality of pieces of information concerning the current position and/or the moving direction of the vehicle obtained with respect to the respective received signals in the previously described manner~
Fig. 27 is a view for explaining still a further embodiment of the present invention. The Fig. 27 embodiment employs the reference stations la, lb and lc which are installed undersea arranged in the vertical direction as spaced from each other. The respective reference stations la, lb and lc are adapted to transmit three ultrasonic signals in the manner described in conjunction with Fig. 1. An undersea moving vehicle such as a submarine 251 serving as a vehicle receives the ultrasonic signal transmitted from any one of the reference stations la, lb and lc. If and when the ultrasonic signal transmitted from the reference station la, for example, reaches a portion, as hatched in Fig. 27, of a considerably different water temperature, the ultrasonic signal is deflected and a situation could occur in which the scanning signal can not be received. Therefore, in such a situation the ultrasonic signals transmitted from the other reference stations lb and lc are received by the vehicle. Accordingly, the system in the vehicle can make measurement of the current position and the moving dir-ection without being influenced by the temperature di*ference in the water.
Fig. 28 is a view showing still a further embodiment of the present inventionO The Fig. 28 embodiment has been adapted such that even when an automo~ile running on a plane suffers from interruption of the electric wave transmitted by the reference station due to another automobile running in front of ' ,~

the above described automobile measurement can be made of the current position and/or the moving direction. More specifically, according to the Fig~ 28 embodiment, two reference stations la and lb are provided on the path of automobiles with different heights. Normally the automobile 262 runs receiving the electric wave transmitted from the reference station lb. When the automobile 262 approaches the rear of a track 261 running in front of the same, the electric wave transmitted from the reference station lb comes to be interrupted by the track 261 and comes not to be able to be received any more. In such a situation~ the automobile 262 is controlled to receive the electric wave transmitted from the reference station la installed at a relatively high position. With the Fig. 28 embodiment as well, the electric waves transmitted from both reference stations la and lb are received simultaneously insofar as there is no obstacle; however, the same approach as previously described may be employed to eliminate such situation.
Now let it be assumed that the height between the reference station la and the receiver borne on the automobile 262 is ha and the height between the reference station lb and the receiver borne on the track 261 is hb. Further let it be assumed that the horizontal distances between the fixed locations of the reference stations la and lb and the automobile 262 and the track 261 are D8 and D9 and the straight line distance from the reference station la to the automobile 262 is da and the straight line distance from the reference station lb to the track 261 is d9. Then d8 and d9 may be expressed by the following e~uations (68) and (69).

:~4~3Z3~

~ 2 2 d8 = ~D8 + ha ----------------- -~----------(68) ~ 2 2 d9 = ~D9 + hb ---~ ----------------(69) By calculating the above describe~ e~uations (68) and (69), the respective horizontal distances D8 and D9 can be obtained. Since the above described constants ha and hb can be known in advance, such calculation can be made with ease by entering D8 and D9 into the microcomputer 6 shown in Fig. 6.
Furthermore, by substituting the respective horizontal distances D8 and D9 for R in the previously described equations (61) and (62), the current position and/or the moving direction of the automobile 261 can be accurately obtained.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present inven-; tion being limited only by the terms of the appended claims.

Claims (46)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A system for measuring at least one of the current position and the direction of a moving vehicle, comprising:
transmitting means installed at a reference location, said transmitting means comprising first transmitting means for transmitting an azimuth scanning signal being scanned in succession in different direc-tions, second transmitting means for transmitting a location information signal representing said reference location of said transmitting means, and third transmitting means for transmitting an azimuth associated information signal containing information concerning a predetermined azimuth, receiving means for receiving said azimuth scanning signals at at least three positions spaced apart from each other by predetermined distances and for receiving said location in-formation signal and said azimuth associated information signal at at least one of said at least three positions, and information processing means borne on said moving vehicle, said information processing means being structured to evaluate at least one of the current position and the direction of said moving vehicle based on the information concerning the respective time periods from receipt of said azimuth associated information signal until receipt of said azimuth scanning signal at said at least three positions, said location information and the information concerning said predetermined distances between said at least three positions.

2. A system in accordance with claim 1, wherein said receiving means comprises at least three receiving portions in-stalled at said at least three positions spaced apart from each other by said predetermined distances.

3. A system in accordance with claim 2, wherein said vehicle comprises a single vehicle, and said at least three re-ceiving portions of said receiving means for receiving the sig-nals from said transmitting means are all installed in said single vehicle, as spaced apart from each other by said predeter-mined distances.

4. A system in accordance with claim 2, wherein said vehicle comprises a single vehicle, and wherein of said at least three receiving portions of said receiving means for receiving the signals from said transmitting means at least two receiving portions are provided in said single vehicle while the remaining receiving portion is installed at a reference location.

5. A system in accordance with claim 1, wherein said vehicle comprises a single vehicle, and wherein said at least three positions include successive positions which are change-able in association with the movement of said vehicle.

6. A system in accordance with claim 2, wherein said vehicle comprises two vehicles, and wherein of said at least three receiving portions of said at least receiving means one receiving portion is installed on one vehicle, while the remain-ing at least two receiving portions are installed on the other vehicle.

7. A system in accordance with claim 1, wherein said transmitting means is adapted to transmit said signals by way of an electromagnetic wave, and wherein said receiving means is structured to receive said electromagnetic wave signals.

8. A system in accordance with claim 7, wherein said electromagnetic wave is an electric wave.

9. A system in accordance with claim 7, wherein said electromagnetic wave is light.

10. A system in accordance with claim 9, wherein said light is laser light.

11. A system in accordance with claim 1, wherein said transmitting means is structured to transmit the respective sig-nals by way of a sound wave or ultrasonic wave, and wherein said receiving means is structured to receive said sound wave signals or the ultrasonic wave signals.

12. A system in accordance with claim 1, which further comprises display means operatively coupled to said information processing means for displaying at least one of the current posi-tion and the moving direction of said moving vehicle.

13. A system in accordance with claim 12, wherein said display means comprises digital display means.

14. A system in accordance with claim 12, wherein said display means comprises a cathode ray tube.

15. A system in accordance with claim 1, wherein said first transmitting means is structured to transmit said azimuth scanning signal in successively different directions in differ-ent phases, whereby the information concerning said time periods is determined based on the phase differences of the azimuth scan-ning signals as received at said at least three positions.

16. A system in accordance with claim 1, wherein said third transmitting means is included in said first transmitting means, said first transmitting means is adapted such that said azimuth scanning signal is reversed each time said azimuth scan-ning signal is directed to said specified azimuth, whereby said information concerning said specified azimuth is contained in said azimuth scanning signal.

17. A system in accordance with claim 16, wherein said first transmitting means is adapted to intermittently trans-mit said scanning signal with a predetermined time difference for each cycle, whereby superposition between a preceding one cycle signal and a succeeding one cycle signal of said azimuth scanning signal is eliminated.

18. A system in accordance with claim 1, wherein said information processing means is adapted to execute the steps of evaluating a first plurality of formulae representing a plurality of lines connecting said each of at least three posi-tions and said reference location where said transmitting means is installed, evaluating a second plurality of formulae representing a plurality of lines connecting said at least three positions one with another, and evaluating said at least three positions by solving said first and second formulae.

19. A system in accordance with claim 18, wherein said first plurality of formulae and said second plurality of formulae contain linear equations.

20. A system in accordance with claim 19, wherein said information processing means is adapted to execute the steps of evaluating an angle of said respective positions with respect to said fixed location where said transmitting means is installed, based on said information concerning the time periods and said location information, and evaluating the gradients of said first plurality of formulae in terms of the tangents of said evaluated angles.

21. A system in accordance with claim 18, wherein said information processing means is adapted to evaluate said direction of the moving vehicle based on the evaluation of the said at least three positions.

22. A system in accordance with claim 1, wherein said information processing means is adapted to execute the steps of evaluating the angles of said at least three positions with respect to said reference location where said transmitting means is installed based on said information concerning the time periods and said location information, evaluating the angles of the position of said vehicle with respect to said reference location based on the maximum and the minimum among said evaluated angles, evaluating a straight line distance from said vehicle to said fixed location based on the position corresponding to said maximum angle and the position corresponding to said minimum angle, and evaluating the position of said vehicle based on the angle of said vehicle with respect to said reference location and said straight line distance.

23. A system in accordance with claim 1, wherein said transmitting means comprises a plurality of transmitting means installed at a plurality of different reference locations, each said transmit-ting means comprising said first transmitting means, said second transmitting means, and said third transmitting means, and in addition fourth transmitting means for transmitting an identi-fying information signal for identifying each said transmitting means, and said receiving means comprises individual signal providing means responsive to said identifying information signal for individually receiving said azimuth scanning signals, said location information signal and said azimuth associated information signal for each said trans-mitting means, and utilization means responsive to said individual signal providing means for utilizing said signals individually provided for each said transmitting means.

24. A system in accordance with claim 23, wherein said transmitting means further comprises time sharing means for enabling said plurality of transmitting means for en-abling transmission on a time sharing basis, and each said fourth transmitting means of each said trans-mitting means comprises means for generating an identifying timing signal for identifying the timing of enabled transmission of each said transmitting means, and said individual signal providing means comprises means responsive to said identifying timing signal for demultiplexing said individually provided signals for each said transmitting means.

25. A system in accordance with claim 23, wherein each said fourth transmitting means of each said trans-mitting means comprises means for generating an identifying code signal for identifying each said transmitting means, and said individual signal providing means comprises means responsive to said identifying code signal for decoding said identifying code signal for providing a decoded identifying signal for identifying each said transmitting means.

26. A system in accordance with claim 23, wherein each said transmitting means comprises means for trans-mitting a modulated wave using a carrier wave, the frequency of said carrier wave of each said transmitting means being selected to be different from each other among said plurality of transmitting means so as to be uniquely identifiable of each said transmitting means, and said individual signal providing means comprises means responsive to said frequency of said carrier wave for identi-fying each said transmitting means.

27. A system in accordance with claim 23, wherein said utilization means comprises individual level de-tecting means for individually level detecting said signal for each said transmitting means.

28. A system in accordance with claim 27, wherein said utilization means further comprises means res-ponsive to said individual level detecting means for selecting said signals of one of said plurality of transmitting means having the maximum signal level.

29. A system in accordance with claim 27, wherein said utilization means comprises means responsive to said individual level detecting means for selecting said sig-nals of one or more of said plurality of transmitting means having a signal level exceeding a predetermined level.

30. A system in accordance with claim 29, wherein said utilization means further comprises mean value means for evaluating a mean value of a plurality of pieces of information concerning at least one of the position and the direction of movement of said moving vehicle evaluated based on said signals of one or more of said plurality of transmitting means.

31. A system in accordance with claim 23, wherein said utilization means comprises mean value means for evaluating a mean value of a plurality of pieces of information concerning at least one of the current position and the moving direction of said moving vehicle evaluated based on said signals from said plurality of transmitting means.

32. A system in accordance with claim 1, which fur-ther comprises, attitude angle detecting means for detecting the atti-tude angle of said moving vehicle.

33. A system in accordance with claim 32, which fur-ther comprises display means operatively coupled to said information processing means for displaying at least one of the position and the direction of movement of said moving vehicle, and wherein said information processing means is adapted to control said display means responsive to the output of said attitude angle detecting means.

34. A system in accordance with claim 33, wherein said information processing means is adapted to dis-able said display means when the attitude angle detected by said attitude angle detecting means exceeds a predetermined value.

35. A system in accordance with claim 32, wherein said information processing means is adapted to cor-rect the distances between said at least three positions respon-sive to the attitude angle detected by said attitude angle detecting means.

36. A system in accordance with claim 35, wherein said information processing means is adapted to evalu-ate the distance in the horizontal direction between said at least three positions based on the cosine of said detected atti-tude angle and said distances between said at least three posi-tions.

37. A system in accordance with claim 36, wherein said at least three positions are selected to be dis-posed on a straight line along the moving direction of said moving vehicle, said attitude angle detecting means comprises means for detecting the angle of elevation of said moving vehicle, and said information processing means is adapted to evalu-ate the distances in the horizontal direction between said at least three positions based on the cosine of said angle of eleva-tion and the distances between said at least three positions.

38. A system in accordance with claim 36, wherein said at least three positions are selected to be dis-posed on a straight line orthogonal to the moving direction of said moving vehicle, said attitude angle detecting means comprises means for detecting the angle of bank of said moving vehicle, and said information processing means is adapted to evalu-ate the distances in the horizontal direction between said at least three positions based on the cosine of said angle of bank and the distances between said at least three positions.

39. A system in accordance with claim 1, which further comprises a portable casing member, and at least one receiving means supporting member displace-ably provided on said portable casing member, said receiving means being provided at said at least one receiving means supporting member.

40. A system in accordance with claim 39, wherein said portable casing member comprises a casing, and said receiving means supporting member comprises one extendable from and retractable within said casing.

41. A system in accordance with claim 39, which fur-ther comprises coefficient generating means for generating a co-efficient associated with displacement of said receiving means supporting member with respect to said portable casing member, and said information processing means is adapted to correct the distances between the position of at least one receiving means provided on said receiving means supporting member and the positions of the other receiving means based on the co-efficient generated by said coefficient generating means.

42. A system in accordance with claim l, wherein said information processing means is adapted to execute the steps of evaluating the angles of said at least three positions with respect to said reference position where said transmitting means is provided based on the information concerning the res-pective time periods, and evaluating at least one of the position and the direction of movement of the said moving vehicle based on said location information, said angles of said at least three posi-tions with respect to said reference location, and the angle defined by lines connecting said at least three positions.

43. A system in accordance with claim 42, wherein said information processing means is adapted to execute the steps of evaluating the center of said at least three positions based on the angle defined by said moving vehicle with respect to said at least three positions, and the angle defined by the lines connecting said at least three positions, and evaluating the position of said moving vehicle by calculating the formula representing the line connecting said center and said predetermined fixed location.

44. A system in accordance with claim 43, wherein said information processing means is adapted to evaluate the direction of movement of said moving vehicle based on the angle of said at least three positions with respect to said predetermined fixed location, and the angle defined by the lines connecting said at least three positions.

45. A system in accordance with claim 44, wherein the lines connecting said at least three positions form a triangle, and the angle defined by the lines connecting said at least three positions contains angular information associated with said angle.

46. A system in accordance with claim 44, wherein said lines connecting said at least three positions constitute a straight line.