Two-way RF ranging system and method for local positioning
First Claim
1. A positioning system, comprising:
- a plurality of devices, each device including;
a transceiver for exchanging RF signals with the other of the plurality of devices;
the transceiver periodically receiving a message from each other device of the plurality of devices during time slots assigned to the other devices;
local clock for generating a local clock signal;
receiver logic for determining a time of arrival, relative to the local clock signal, of the message from each of the other devices;
transmitter logic for periodically transmitting messages to the other devices during a time slot assigned to said device, each transmitted message including information representing the determined time of arrival for at least one of the other devices;
wherein the received message from each other device includes information representing a time of arrival at the other device of a respective message transmitted by said device;
at least one of the devices further including ranging logic for determining a respective range to each of a plurality of the other devices, said determined respective range to a respective device of the other devices being determined as function of the determined time of arrival of the message from the other device and the time of arrival information in the message from the other device.
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Accused Products
Abstract
A positioning system includes a plurality of devices configured to exchange RF signals with one another. A first device periodically receives a message from each other device during time slots assigned them. The received message includes information representing a time of arrival at the other device of a respective message transmitted by the first device. A time of arrival of the message from each of the other devices is determined by the first device. The first device periodically transmits messages to the other devices, each transmitted message including information representing the determined time of arrival for at least one of the other devices. A range from the first device to each of a plurality of the other devices is determined as function of the determined time of arrival of the message from the other device and the time of arrival information in the message from the other device.
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Citations
39 Claims
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1. A positioning system, comprising:
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a plurality of devices, each device including; a transceiver for exchanging RF signals with the other of the plurality of devices;
the transceiver periodically receiving a message from each other device of the plurality of devices during time slots assigned to the other devices;local clock for generating a local clock signal; receiver logic for determining a time of arrival, relative to the local clock signal, of the message from each of the other devices; transmitter logic for periodically transmitting messages to the other devices during a time slot assigned to said device, each transmitted message including information representing the determined time of arrival for at least one of the other devices; wherein the received message from each other device includes information representing a time of arrival at the other device of a respective message transmitted by said device; at least one of the devices further including ranging logic for determining a respective range to each of a plurality of the other devices, said determined respective range to a respective device of the other devices being determined as function of the determined time of arrival of the message from the other device and the time of arrival information in the message from the other device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A device for use in a positioning system, the device comprising:
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a receiver for receiving a message signals from another device in the positioning system during a time slot assigned to the other device; a local clock for generating a local clock signal, the local clock including a local oscillator; receiver logic for determining a time of arrival, relative to the local clock signal, of the message from the other device; ranging logic for determining a respective range to the other device as a function of the determined time of arrival; and clock synchronization logic, including clock steering logic that includes a register storing an adjustment value, and an analog clock signal generator responsive to the local oscillator and the adjustment value in the register for generating a steered clock signal that is approximately synchronized with a local clock in the other device; wherein the receiver logic is configured to utilize the steered clock signal to deterimine a difference between an edge in the steered clock signal and an edge in the message from the other device. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. A method of operating a positioning system having a plurality of devices, each device configured to exchange RF signals with the other of the plurality of devices, comprising the steps of:
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periodically receiving, at a first device, a message from each other device of the plurality of devices during time slots assigned to the other devices, the received message from each other device including information representing a time of arrival at the other device of a respective message transmitted by the first device; determining a time of arrival, relative to a local clock signal of a local clock of the first device, of the message from each of the other devices; periodically transmitting messages to the other devices during a time slot assigned to the first device, each transmitted message including information representing the determined time of arrival for at least one of the other devices; and determining a respective range from the first device to each of a plurality of the other devices, said determined respective range to a respective device of the other devices being determined as function of the determined time of arrival of the message from the other device and the time of arrival information in the message from the other device. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A method for operating a device in a positioning system, comprising:
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receiving a message signal from another device in the positioning system during a time slot assigned to the other device; generating a local clock signal; determining a time of arrival, relative to the local clock signal, of the message from the other device; determining a respective range to the other device as a function of the determined time of arrival; storing an adjustment value in a register; and generating, based on the adjustment value, a steered clock signal that is approximately synchronized with a local clock of the other device; wherein the method includes determining a difference between an edge in the steered clock signal and an edge in the message from the other device. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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Specification