IE63127B1

IE63127B1 - Installation for the transmission of data between a track and a vehicle travelling on it

Info

Publication number: IE63127B1
Application number: IE167787A
Authority: IE
Inventors: George Francis Grassart; Emile Charles Binard; Louis Jean Paul Gilsoul
Original assignee: Acec Transport Sa
Priority date: 1986-06-24
Filing date: 1987-06-24
Publication date: 1995-03-22
Also published as: PT85160B; EP0252199B1; DZ1099A1; TNSN87122A1; CA1290810C; EP0252199A1; DE3674205D1; IE871677L; PT85160A; ES2006769A6; MA21012A1; ATE56403T1

Abstract

1. Installation for the point-to-point transmission of data between the track and a vehicle travelling on this, consisting of ground equipment (5) fastened to the track and comprising a transmitter which transmits the coded information from a track signal (11) by means of a transmission marker (9), and of on-board equipment (1) accommodated in the vehicle (3) and comprising a receiver (151, 152, 153) connected to at least one reception antenna (13, 15) fastened underneath the vehicle (3) so as to correspond to the transmission marker (9), and at least one computer (155, 156, 157) for decoding and processing the received information, the said computer being connected to a display panel (160), characterized in that the ground equipment (5) comprises at least one means (33, 37, 39) for the sequential binary coding of the track signalling information (11), an active magnetic-field frequency-modulation transmitter (41, 43, 45, 47), a means (51, 53, 55, 57) for comparing the amplitude of the transmitted magnetic field with a threshold and a means (63, 67, 69, 70) for checking the transmitted frequency by means of a transmission marker (9), the means (51, 53, 55, 57) of comparison of the amplitude of the transmitted magnetic field and the means (63, 676 (sic), 69, 57) for checking the transmission frequency being connected to a safety-signal command means (61).

Description

The present invention is concerned with an installation for the punctual transmission of data between a track and a vehicle travelling on it, which comprises a fixed emitter on the track and a receiver lodged in the vehicle such as a vehicle for a railway, tram, subway, etc.

Traditionally, the movement of railway vehicles is regulated by signals installed along the track, which guarantees a high degree of security.

However, the responsibility with respect to the information given by the signalling installations is entirely confided to the driver who must assimilate them in conditions which are sometimes difficult: travelling in fog or during snowfalls, almost horizontal sunshine, etc.

It is therefore important for traffic safety to equip the driving cab with apparatus whose double function is to repeat on board the appearance of the signals and to control the action of the driver in different situations created during the journey by the appearance of the signals; in the case of possible negligence on the part of the driver, the system stops the vehicle automatically.

Furthermore, a high capacity transmission of data is necessary to achieve an effective control of speed.

As a matter of fact, it should at least be possible to transmit punctually data concerning the appearance of the signals, the gradient of the track, the speed to be respected and the distance to the next signal, and the speed of the line.

The apparatus for transmission and processing of data should present a - 2 very high degree of reliability in operation, even in very difficult conditions: extreme temperatures, vibrations, shocks, humidity, dusts, disturbing electromagnetic environment, etc. In addition, they should present a high degree of availability, that is to say they can only give rise to a minimum of incidents or inopportune actions (for example erroneous braking commands) which will cause inadmissable disturbances in the traffic. Finally, this transmission from track to machine should be able to function right up to the highest traffic speeds.

One of the difficulties, within the framework of reliable operation, resides in the selection of the appropriate fixed emitters on the track travelled by the vehicle and corresponding to its direction of movement. Furthermore, another difficulty resides in the transmission at a sufficient level to guarantee certain reception of the messages by the receiver lodged in the vehicle.

An installation is known for the punctual transmission of data between the track and the vehicle travelling on it, which comprises a passive emitter (called a transponder) fixed on the track and a receiver lodged in the vehicle travelling on it, the passive emitter being activated by a level of emission originating from the vehicle. In this manner, one is certain to receive the data from the correct emitter. Furthermore, the absorption of the energy of emission by the passive emitter can be detected which enables a computer to establish the presence of an emitter. This installation known per se satisfies the requirements set out above, but it is very cumbersome and it consumes much energy for the activation of the passive emitters. Furthermore, it is necessary to ensure a sufficient energy level transmitted towards the passive emitters, and to do this taking account of the irregularities in the tracks and therefore the variations of the distance between the emitting activation antenna and the passive emitter to be activated. Besides, the known installation is complex and onerous.

Consequently, the present invention has the object of providing a novel installation of the above-mentioned type corresponding to the requirements of safety and reliability set out above and fulfilling the required functions. - 3 Another object of the present invention aims to provide an installation of the above-mentioned type which mitigates the disadvantages of the installations of the state of the art.

Another object of the present invention aims to provide an installation of the above-mentioned type which permits the selection with total reliability, of the correct emitters solidly joined to the track, rejecting the emitters of a parallel track or corresponding to the reverse direction of travel; which enable a guarantee of a sufficient level of emission, failing which a security signal is engaged; which permits a guarantee of a correct frequency of emission, failing which a security signal is engaged; and which permits a correct coding and decoding of the data transmitted as well as reliable processing of the same.

The objects of the present invention are achieved by an installation for punctual transmission of data between the track and a vehicle travelling thereon, constituted by a ground apparatus fixed on the track comprising an emitter which transmits the coded data from a track signal with the aid of an emission beacon, as well as on-board apparatus lodged in the vehicle comprising a receiver connected to at least one reception antenna fixed below the vehicle so as to correspond with the emission beacon, and at least one computer for decoding and processing the data received, the said computer being connected to a display and reading panel as well as a device for controlling the brakes, characterised in that the ground apparatus comprises at least one means for binary sequential coding of the data from the track signals, an active emitter which modulates the frequency of a magnetic field, a means of comparison with a threshold of the amplitude of the magnetic field emitted, and a means for control of the frequency emitted with the aid of an emission beacon, the means of comparison of the amplitude of the magnetic field emitted and the means of control of the frequency of emission being connected to a means of command of a safefy signal, such as the change to red in the track signal.

Thanks to the transmission installation in accordance with the present invention, in which the level of emission and the frequency of emission - 4 are controlled, it is possible to transmit coded data in a certain manner.

One can also augment the safety of operation of the installation in accordance with the present invention, by using a particular coding of the signals, in which the hamming distance is elevated. Advantageously, a message is composed of seven octets, of which two are synchronisation octets and five are data octets, of which each can transmit one piece of data among ten: so as to preserve a distance of hamming of four. The coding precautions thus taken guarantee that to transform a correct message into a wrongly interpretable message, it is necessary to transform at least four bits. One can thus achieve the coding in two different manners on the basis of divided data so that one half of the emitted message is coded in one manner and the other half in the other manner; the emission of consistent messages thus reveals the similarity of the two results and consequently their correctness.

In accordance with one particularly preferred embodiment, the means for comparison of the amplitude of the magnetic field emitted with the aid of a tuned LC circuit comprises an intensity transformer whose primary winding is found in the primary circuit of the transformer of the tuned LC circuit, and a rectifier whose continuous output current, which is proportional to the amplitude of the field, is sent via an appropriate interface to a core called a magnetic amplifier which releases a safety signal via a command relay when the said continuous current is less than a continuous threshold current generated independently.

Preferably the means of control of the modulated frequency comprises essentially at least a clock, a means of reading the modulated frequency, a means of picking up coded messages, a means for decoding the same, a means for selecting and classifying decoded messages into three categories: a) non-conforming messages to be rejected, b) conforming messages implying the stopping of the vehicle, and c) conforming messages permitting the passage of the vehicle, a means permitting the connection of the frequency of the clock to the variations of the modulated frequency in such a manner that the - 5 frequency of the clock permits a more or less rapid sampling of the message in thus furnishing messages classified under b) or c) if the modulated frequency is correct, or under a) if the modulated frequency has suffered any variation, the said control means being connected to a means for commanding a safety signal.

Advantageously, the signal classified under a), b) or c) is compared in a magnetic amplifier, preferably the same magnetic amplifier which serves as the means for comparison of the amplitude of the emitted magnetic field, to a reference dependent on the real state of the track signal, the said magnetic amplifier being able to trigger a safety signal such as a red danger signal.

As already mentioned previously, the emission beacon is mounted on the track advantageously offset towards the left in relationship to the axis of the track, viewed in the direction of travel of the vehicle; in this way, a track used in the two traffic directions can comprise beacons corresponding to the desired direction of travel, on each side of the axis of the track.

The on-board equipment comprises, inter alia, a receiver joined to at least one exterior reception antenna fixed below the vehicle, offset in relation to the axis of the track, viewed in the direction of travel. Each reception antenna consists advantageously of a winding wound to the left and a winding wound to the right, mounted one beside the other, on the same axis. This arrangement permits particularly the rejection of emission beacons corresponding to the opposite direction of travel or to parallel tracks. This particular arrangement of the antenna permits therefore the selection with complete safety of an appropriate emission beacon. As a matter of fact, the magnetic fluxes perceived by the left and right windings of an antenna are in the same phase when the correct emission beacon passes below the antenna; on the contrary, if a parasite beacon of a parallel track or from the other direction of travel of the vehicle is picked up by the above-mentioned antenna, the two windings of the same pick up a magnetic flux of the same orientation and consequently the signals emitted by the said opposed windings are in opposite phases. This permits the on-board device to select the appropriate beacons with complete safety. - 6 The signals picked up by the receiver antenna on board the vehicle are then decoded and processed by electronic computers, optionally doubled or tripled for reasons of safety. The equipment on board can also comprise a speed gauge whose signals are also processed in the computers for controlling the movement by means of a programme intended for this purpose.

The output variables are the illumination of the lamps at the display panel and the control of braking when the conductor does not follow instructions.

Other details of the present invention will appear in the following description of one particular embodiment,, with reference to the drawings, in which: Figure 1 represents a general schematic view of the installation according to the present invention; Figure 2 represents schematically a message; Figure 3 is a schematic view of the ground equipment in accordance with one preferred embodiment of the invention; Figure 4 is a sectional view of an emission beacon; Figure 5 represents the crossing of a normal beacon by the reception antenna of the on-board equipment; Figure 6 represents the crossing of a parasite emission beacon by the reception antenna; and Figure 7 is a schematic view of the principle of functioning of the on-board equipment.

In the Figures, identical reference numerals are used for identical or analogous elements.

With reference to Figure 1, the installation comprises an on-board apparatus 1 mounted in a vehicle 3 and a ground equipment 5 placed along the track 7.

The ground equipment codes and permanently emits, by means of a beacon 9, a binary message repeated indefinitely, coding data originating from - 7 a track signal 11, for example.

An antenna 13, 15 installed under each driving cab of the vehicle enables the pick up during passage over a beacon 9 of the binary message which it emits.

The on-board equipment 1 comprises circuits for reception, modulation and validation of the message received on the antenna, circuits for processing the data picked up on the track, and originating from the driving station and the speed gauge 17, and finally brake control circuits 19 and circuits giving to the driver data originating from the track and from orders.

The transmission is achieved by modulation of the frequency of the magnetic field radiated by a loop tuned to 100 KHz.

The message is for example composed of 56 bits comprising 16 bits of synchronisation (two octets: and Sg) and 40 bits of data (5 octets) (see Figure 2); it lasts for 2.24 ms at the telegraphic speed used of 25 Kbaud. Each useful octet can transmit one piece of data among ten. In other words, among the 256 possible combinations of eight bits, only ten combinations are normally authorised. In the case where the coder cannot determine the piece of data to be transmitted, it transmits an 11th combination called doubtful aspect. The coding precautions thus taken guarantee a hamming distance of 4 for a simple message: in other words, to transform a correct message into a message which is wrongly interpretable, it is necessary to falsify at least four bits.

One of the principal functions of the ground equipment 5 (Figure 3) is to determine in a certain manner the value of the code to be given to each octet of the message on the basis of the data originating from the track 11 (colour of the signal, type of signal, speed to be respected, etc). Within this aim, the coding is achieved in two different manners on the basis of divided data in such a manner that one half of the message emitted may be coded in one manner and the other half in the other manner; the emission of consistent messages thus reveals the similarity of the two codings and consequently their correctness. - 8 The data 31 originating from the track 11 are coded in two different manners by a coding means 33, provided with a clock 35 in a manner known per se. The bits of the message thus coded are sent, one message in two being inverted, into a shift register 37 which puts them in series for transmitting them, via a logic gate 39 inverting one message in two, to a modulator 41 for defining there the frequency to be injected, after amplification at 43 and galvanic insulation at 45 into the loop 47 of the emission beacon 9 (0: 90 KHz; 1: 110 KHz). The ground equipment thus comprises a control means with good refreshment (clearing) for the shift register 33, which comprises the logic gate 39 commanded by the clock 35.

Another principal function of the ground equipment 5 is to guarantee in a certain manner the on-board detection of the emission beacon by a sufficient level of emission and by a correct frequency of modulation. Inter alia, it should guarantee the emission of a stop message each time that the track signal 11 is closedC'on).

In order to control the level of emission, the primary loop 47 of the beacon 9 comprises an intensity (current) transformer 51 tuned in series, the secondary winding of which provides, via a rectifying and filtering cell 53, a continuous current proportional to the level of the emitted magnetic field which is led into the housing 5. At an interface 55 the continuous current is conducted to a core 57 called the saturable magnetic amplifier where it is compared to a predetermined threshold 59. If the continuous current is too weak, that is to say if the amplitude of the magnetic field is insufficient, the said magnetic amplifier 57 is unbalanced and commands an exterior relay 61 which activates the stop signal on the track.

In order to control the frequency of emission, the ground equipment comprises a circuit 63. This comprises essentially at least one clock 65, a means for reading the modulated frequency, a means of capturing coded messages, a means of decoding the same, a means of selecting and of classifying the decoded messages into three categories: a) non-conforming messages to be rejected; b) conforming messages which involve the stopping - 9 of the vehicles; and c) conforming messages permitting the passage of the vehicles, a means permitting the connection of the frequency of the clock to the variations in the modulated frequency in such a manner that the frequency of the clock enables a more or less rapid sampling of the * message in furnishing thus messages classified under b) or c) if the modulated frequency is correct or under a) if the modulated frequency has undergone any variation, the said control means being connected to a command means of a safety signal.

The said circuit 63 enables variation of the frequency of the clock as a function of the possible variations of the modulated frequency. It captures also the message upstream of the modulator. When the modulated frequency varies, the sampling of the message to be transmitted varies also and the message read is a nonconforming message. Whe the frequency of emission is correct, the sampling is carried out normally and the message read after sampling is consistent. The circuit 63 thus effects a classification of the messages obtained into three categories: a) messages not conforming to the code, to be rejected; b) messages conforming to the code, signifying stopping; c) messages conforming to the code, signifying passage.

The signal thus obtained (a, b or c) is sent via an interface 67 to a magnetic amplifier of the type above mentioned, preferably the same as that which is used for the control of the level of emission. It is there compared to a control current for closing the stop signal 69. If the signal has been classified under a), it does not correspond to the signal 69 and the magnetic amplifier 57 activates the command relay of the stop signal. If the signal has been classified under b) or c), the magnetic amplifier compares it to the state of the stop signal 69 (open or closed - off or on) and activates the command relay 61 if necessary. - 10 With reference to Figure 4 and according to a preferred embodiment of the present invention, the beacon 9 is constituted by a single spiral 91 of stainless steel of 80 cm length forming the secondary circuit of a magnetic circuit transformer into the primary circuit 47 of which the modulated current is injected (input). The primary winding is advantageously mounted on the axle 93 disposed in the interior of the single spiral 91, perpendicular to the plane of the same. The single spiral, being sufficiently rigid, is mounted between the rails by means of two opposed S-shaped tongues 95 and 97. Advantageously, the primary circuit 47 is cast in a casing fixed below the fixation tongue 95.

The beacon 9 is mounted between the rails 101 and 102 and is decentred in relation to the axis of the track in such a manner as to define the direction of circulation.

The voltage modulated in frequency is picked up on the terminals of an antenna 13 mounted below each driving station of the vehicle, that is to say in a manner offset to the left if the beacons are mounted in a manner offset to the left, in the direction of travel.

According to one advantageous embodiment, and in order to avoid the pickup of signals originating from a parasite beacon, for example a beacon of another track or from the opposite track (in the opposite direction) the antennae 13,15 comprise two windings 131 and 133 of which one is wound to the left and the other to the right. Thus, as shown in Figure 5, when the antenna passes over a beacon which is intended for the chosen direction of movement, the magnetic fluxes which are opposed one in relation to the other are picked up in the opposed windings and there are therefore in phase concordance. On the contrary, as shown in Figure 6, when the antenna picks up the field emitted by a beacon 9 of the opposite track, this crosses the two opposed windings and the currents produced in the windings 131 and 133 are therefore in opposite phases. A microcomputer can be put in charge of management of the reception of the beacons 9.

The on-board equipment comprises a microcomputer 151,152,153 in charge of management of the reception of the beacons, that is to say to detect the presence of a beacon, to read at least two consecutive identical - 11 messages, to verify the conformity to the code of the octets of data (decades) which amounts to verifying the refreshment of the shift register and comparing the two codings achieved on the ground, and in case of success, to transmit on a data-processing bus of great speed, according to an appropriate protocol, the data picked up on the track, without decoding them. In the case of detection of a beacon whose message is unintelligible, a special message alarm transmission is sent on the data processing bus.

Finally, one or several computers (155,156,157) can derive the data necessary to achieve the programme of controlling travel as appropriate.

Having regard to the requirements of safety and availability, all the functions described up to now have been triplicated and the output variables of the three chains thus formed I, II and III (braking control 161, illumination of lamps on the instrument panel 163, recording 165) are submitted to a majority vote called two out of three, that is to say that the agreement of the results of two computers out of three concerning an output variable permits it to be acted upon (159).

One can also achieve at regular intervals tests intended to detect any faults in the processing circuits.

The on-board equipment can also comprise other additional circuits, such the control of the braking curve 167,168 and 168 with majority vote 170 and the entry of complementary parameters in the computers 155, 156 and 157, like a speed check or otherwise.

It is quite evident that the circuits described above also comprise all the auxiliary means known per se such as power feeds, loops for regulation and otherwise, the representations of the figures giving only the principle of operation in accordance with the invention.

Claims

1. Installation for point-wise transmission of data between a track and a vehicle travelling on it, constituted by ground equipment fixed on the track comprising an emitter which transmits the coded data from a track signal by means of an emission beacon as well as on-board equipment lodged in the vehicle comprising a receiver connected to at least one reception antenna fixed beneath the vehicle in such a way as to correspond with the emission beacon, and at least one computer for decoding and processing the data received, said computer being connected to a display panel characterised in that the ground equipment comprises at least one means for sequential binary coding of the data from the track signal, an active emitter of a modulated frequency of a magnetic field, a means of comparison with a threshold of the amplitude of the magnetic field emitted, and a means of control of the frequency emitted with the assistance of an emission beacon, the means of comparison of the amplitude of the magnetic field emitted and the means of control of the frequency of emission being connected to a means of command of a safety signal.

2. Installation according to Claim 1 characterised in that the means for comparison of the amplitude of the magnetic field emitted with the assistance of a tuned LC circuit comprises an intensity (current) transformer whose primary winding is located in the primary circuit of the transformer of the tuned LC circuit, and a rectifier whose continuous output current which is proportional to the amplitude of the field is sent via an appropriate interface onto a core called magnetic amplifier which triggers a safety signal via a command relay when the said continuous current is lower than a continuous threshold current generated independently.

3. Installation according to Claim 1 or 2 characterised in that the means for control of the modulated frequency comprises essentially at least one clock, a means for reading the modulated frequency, a means for picking up coded messages, a means for decoding the same, a means for selecting and classifying decoded messages into three categories: - 13 a) non-conforming messages to be rejected, b) conforming messages which involve the stopping of the vehicle, and c) conforming messages permitting the passage of the vehicle, a means permitting the connection of the frequency of the clock to the variations of the modulated frequency in such a manner that the frequency of the clock permits a more or less rapid checking of the message, thus furnishing messages classified under (b) or (c) if the modulated frequency is correct or under (a) if the modulated frequency has suffered any variation, the said means of control being connected to a command means for a safety signal.

4. Installation according to Claim 1 characterised in that the means for control of the modulated frequency is connected to a magnetic amplifier preferably the same magnetic amplifier which serves as the means of comparison of the amplitude of the magnetic field emitted, in which the output signal of the same is compared to a reference dependent on the real state of the track signal, the said magnetic amplifier being able to trigger a safety signal.

5. Installation according to any of the preceding Claims characterised in that the ground equipment comprises a control means for good refreshment (clearing) of the shift register by the coding means, comprising the logic gate commanded by the clock.

6. Installation according to any of the preceding Claims characterised in that the beacon is mounted between the two rails of a track in an off-centre manner in relation to the axis of the track.

7. Installation according to any of the preceding Claims characterised in that the beacon consists of a single sufficiently rigid spiral which forms the secondary winding of a magnetic circuit transformer in the primary circuit to which is input the current modulated in frequency.

8. Installation according to Claim 4 characterised in that the primary winding is mounted in the interior of the single spiral - 14 r λ ( on an axle perpendicular to the plane of the said spiral which is fixed on the track by the intermediary of S-shaped tongues .

9. Installation according to any of the preceding Claims 5 characterised in that the on-board equipment comprises essentially at least one receiver of signals picked up by the corresponding antenna , at least one microcomputer in charge of management of the reception of the transmitted signals, a decoder for the same, and at least one microcomputer for achieving the travel control programme which is 10. Connected to a display panel for example, and optionally at least one microcomputer for the control of the braking curve.

10. Installation according to any of the preceding Claims \ characterised in that the reception antenna mounted below the vehicle 15 in concordance with the beacons is composed of two windings of which one is wound to the left and the other to the right, as defined in Claim 1

11. Installation/for transmission of data from a track to a vehicle travelling on it, substantially as described herein with reference to 20 the accompanying drawings. Dated this 24 day of June 1987 BY: TOMKINS & CO Applicants' Agents SIGNED: 5 Dartmouth Road DUBLIN 6 - 15 35 ACEC S.A. 6 Sheets of Drawings Sheet No. 1 •V 1/6 Lj γ CO Θ fe