Route surveillance system
First Claim
Patent Images
1. A system for surveying traffic along a route, comprising:
- a series of sensors fixedly disposed along said route, each of said sensors having an operating range limited to a route section respectively assigned thereto, the route sections assigned to said series of sensors sequentially adjoining one another;
normally inactive monitoring means in each sensor triggerable into an active condition for emitting an output signal in the presence of a vehicle in the assigned route section;
a control post including a source of recurrent start pulses and indicator means for the output signals of said sensors;
a first two-way signal link between said control post and the first sensor in the series for transmitting said start pulses to said monitoring means thereof to trigger same into said active condition and for delivering an output signal therefrom to said indicator means;
a further two-way signal link between each preceding sensor and the immediately following sensor in the series for transmitting trigger pulses to the monitoring means of said immediately following sensor to activate same and for delivering an output signal therefrom to the immediately preceding sensor for retransmission to said indicator means by way of all intervening sensors; and
pulse-generating means in each preceding sensor for producing an outgoing trigger pulse for the immediately succeeding sensor in response to an incoming trigger pulse from said control post in the case of said first sensor and from preceding sensors in all other instances.
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Abstract
A route or a section thereof is monitored by sensors distributed therealong which are identical and are triggered sequentially one from another after a certain delay in each case, the first of these sensors being triggered by a master pulse. The responses from the sensors which indicate the presence of a vehicle are retransmitted to a control device through the preceding sensors. The sensors comprise each a miniature transmitter and a miniature receiver which are slightly coupled to each other when in operation, the coupling being intensified in the presence of a vehicle in the operating zone of a sensor.
18 Citations
9 Claims
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1. A system for surveying traffic along a route, comprising:
- a series of sensors fixedly disposed along said route, each of said sensors having an operating range limited to a route section respectively assigned thereto, the route sections assigned to said series of sensors sequentially adjoining one another;
normally inactive monitoring means in each sensor triggerable into an active condition for emitting an output signal in the presence of a vehicle in the assigned route section;
a control post including a source of recurrent start pulses and indicator means for the output signals of said sensors;
a first two-way signal link between said control post and the first sensor in the series for transmitting said start pulses to said monitoring means thereof to trigger same into said active condition and for delivering an output signal therefrom to said indicator means;
a further two-way signal link between each preceding sensor and the immediately following sensor in the series for transmitting trigger pulses to the monitoring means of said immediately following sensor to activate same and for delivering an output signal therefrom to the immediately preceding sensor for retransmission to said indicator means by way of all intervening sensors; and
pulse-generating means in each preceding sensor for producing an outgoing trigger pulse for the immediately succeeding sensor in response to an incoming trigger pulse from said control post in the case of said first sensor and from preceding sensors in all other instances.
- a series of sensors fixedly disposed along said route, each of said sensors having an operating range limited to a route section respectively assigned thereto, the route sections assigned to said series of sensors sequentially adjoining one another;
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2. A system as defined in claim 1 wherein said pulse-generating means includes pulse-replicating means operating with a predetermined delay period.
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3. A system as defined in claim 2 wherein said pulse-replicating means comprises a monostable circuit.
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4. A system as defined in claim 2 wherein said monitoring means comprises a transmitter and a receiver of electromagnetic waves each provided with an activating input, said activating inputs being connected in parallel with each other and with an input of said pulse-replicating means to a signal-link branch carrying incoming trigger pulses.
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5. A system as defined in claim 4 wherein said transmitter and said receiver are provided with respective antennas loosely coupled to each other in the absence of near-by vehicles but intensifying the coupling in the presence of such vehicles.
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6. A system as defined in claim 2 wherein said delay period is substantially identical for all sensors.
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7. A system as defined in claim 2, further comprising signal-regenerating means in each preceding sensor connected to receive output signals from the monitoring means thereof and from any succeeding sensor for retransmission to said indicator means in their order of generation.
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8. A system as defined in claim 7 wherein said signal-regenerating means comprises a monostable circuit.
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9. A system as defined in claim 8 wherein said indicator means comprises a display device having a synchronizing input connected to said source of start pulses.
Specification