System and method for establishing the instantaneous speed of an object
First Claim
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1. System for establishing the instantaneous speed, in a reliable manner, of an object (1) which is travelling along a known trajectory, in particular a vehicle such as a train, the system comprising:
- means (3, 7) for approximately locating the object and direction of its movement, and means (6) for receiving at least one signal transmitted at a predetermined frequency, known to the object, from at least one satellite (4, 5) and means (8) for calculating and analysing the signal comprising;
means (10) for measuring the frequency shift of the signal received relative to the predetermined frequency of the signal transmitted, which means (10) are connected to means (12) for establishing the vectorial difference of the speeds of the object and the satellite in the satellite/object direction by calculating the Doppler effect which has generated the frequency shift and means (13) for calculating the instantaneous speed in the movement direction of the object based on the vectorial difference established previously, characterized in that the measurements of the frequency shift and the associated calculations are repeated independently on signals from at least two different satellites, and in that the calculation and analysis means (8) further comprise means (14) for combining the results obtained independently in order to obtain an instantaneous speed with the desired level of reliability.
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Abstract
The invention relates to a system for establishing the speed, in a reliable manner, of an object (1) which is travelling along a known trajectory, comprising:
- means (3, 7) for locating the object and direction of its movement,
- means (6) for receiving a signal from a satellite (4, 5) and
- calculation means (8) comprising: means for measuring the frequency shift of the signal received relative to the frequency of the signal transmitted, means for establishing the vectorial difference of the speeds of the object and the satellite by calculating the Doppler effect and, means for calculating the speed in the movement direction of the object, and, the measurements of the frequency shift being repeated independently on signals from a plurality of satellites, means for combining the results obtained in order to obtain a speed with the desired level of reliability.
15 Citations
7 Claims
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1. System for establishing the instantaneous speed, in a reliable manner, of an object (1) which is travelling along a known trajectory, in particular a vehicle such as a train, the system comprising:
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means (3, 7) for approximately locating the object and direction of its movement, and means (6) for receiving at least one signal transmitted at a predetermined frequency, known to the object, from at least one satellite (4, 5) and means (8) for calculating and analysing the signal comprising;
means (10) for measuring the frequency shift of the signal received relative to the predetermined frequency of the signal transmitted, which means (10) are connected to means (12) for establishing the vectorial difference of the speeds of the object and the satellite in the satellite/object direction by calculating the Doppler effect which has generated the frequency shift and means (13) for calculating the instantaneous speed in the movement direction of the object based on the vectorial difference established previously, characterized in that the measurements of the frequency shift and the associated calculations are repeated independently on signals from at least two different satellites, and in that the calculation and analysis means (8) further comprise means (14) for combining the results obtained independently in order to obtain an instantaneous speed with the desired level of reliability. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Method for establishing the instantaneous speed of an object which is travelling along a known trajectory, characterized in that it comprises the steps of:
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establishing the approximate location and movement direction of the object, receiving at least one signal transmitted at a predetermined frequency, known to the object, from at least one satellite, measuring the frequency of the signal received by the object, measuring the frequency shift of the signal received relative to the predetermined frequency of the signal transmitted, establishing the vectorial difference of the speeds of the object and the satellite in the satellite/object direction by calculating the Doppler effect which has generated the frequency shift and calculating the instantaneous speed of the object in the movement direction of the object based on the instantaneous speed established previously.
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Specification