Method of measuring a distance between two radio-communication devices and device adapted to implement one such method
First Claim
1. A method of measuring a distance between two radiocommunication devices, comprising the following steps:
- a—
by a first radiocommunication device of the two radiocommunication devices;
transmitting a radio signal requesting a measurement of an exchange delay between the two devices;
b—
by a second radiocommunication device of the two radiocommunication devices;
receiving the request signal; and
sending an acknowledgement radio signal after an intermediate delay known to both the first and the second devices;
c—
by the first device;
receiving the acknowledgement signal;
measuring the time between transmitting the request signal and receiving the acknowledgement signal;
storing said measured time as the exchange delay; and
calculating a first time of flight of the request signal and of the acknowledgement signal based on the exchange delay and the intermediate delay; and
d—
by the second device;
transmitting a single channel measurement frame configured so that the first device;
determines, from various radio signals received corresponding to the single channel measurement frame, a difference in time of flight between a propagation path corresponding to said first time of flight and the shortest propagation path followed by the radio signals transmitted between the two devices; and
calculates a second time of flight from the first time of flight and the difference in time of flight.
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Accused Products
Abstract
The invention relates to a method of measuring a distance between two radio-communication devices (1, 2), consisting in measuring a radio signal exchange delay. According to the invention, the time-of-flight of the signals is calculated from the exchange delay and subsequently corrected using an analysis of a single channel measuring frame that is transmitted between the two devices. The corrected time-of-flight corresponds to the shortest propagation path followed by the radio signals. In the majority of radio transmission medium configurations, the corrected time-of-flight is a straight line measurement of the distance separating the two devices (1, 2).
23 Citations
13 Claims
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1. A method of measuring a distance between two radiocommunication devices, comprising the following steps:
-
a—
by a first radiocommunication device of the two radiocommunication devices;transmitting a radio signal requesting a measurement of an exchange delay between the two devices; b—
by a second radiocommunication device of the two radiocommunication devices;receiving the request signal; and sending an acknowledgement radio signal after an intermediate delay known to both the first and the second devices; c—
by the first device;receiving the acknowledgement signal; measuring the time between transmitting the request signal and receiving the acknowledgement signal; storing said measured time as the exchange delay; and calculating a first time of flight of the request signal and of the acknowledgement signal based on the exchange delay and the intermediate delay; and d—
by the second device;transmitting a single channel measurement frame configured so that the first device; determines, from various radio signals received corresponding to the single channel measurement frame, a difference in time of flight between a propagation path corresponding to said first time of flight and the shortest propagation path followed by the radio signals transmitted between the two devices; and calculates a second time of flight from the first time of flight and the difference in time of flight. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification