System and method for improving the accuracy of time of arrival measurements in a wireless ad-hoc communications network
First Claim
1. A method to determine signal propagation time between nodes in an ad-hoc communications network, said nodes being adapted to transmit and receive signals to and from other nodes in said ad-hoc network, the method comprising:
- controlling a first node of said plurality to receive at least one signal communicated from a second node, and to calculate a response based on said signal;
controlling said first node to calculate an auto-correlation function of said response, and to calculate an approximate peak value of a quadratic approximation based on said auto-correlation function;
controlling said first node to determine a signal sampling phase offset between said response and said approximate peak value and in response, to calculate an actual peak value of said response; and
controlling said first node to calculate an actual reception time for said at least one signal at said first node based on said actual peak value, and to determine, based on said actual reception time, a signal propagation time.
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Accused Products
Abstract
A system and method for improved Time Of Arrival (TOA) distance measurements between nodes of a wireless ad-hoc network. Specifically, the present invention is a system and method of distance estimation using square-root raised-cosine pulse shaping and chip matched filters on direct sequence spreading waveforms, the multiplication of which produces raised-cosine filtered pulse responses. The responses are used to identify a time when a function is at a maximum, corresponding to the actual signal reception time. The system and method produces a raised-cosine filtered pulse response and an auto-correlation function based on a received signal. A peak value of the auto-correlation function is calculated based on a quadratic approximation, which is corrected using a signal sampling phase offset detected between the raised-cosine filtered pulse response and the calculated peak value. The calculated peak value is then corrected to represent an actual reception time for received signals.
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Citations
24 Claims
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1. A method to determine signal propagation time between nodes in an ad-hoc communications network, said nodes being adapted to transmit and receive signals to and from other nodes in said ad-hoc network, the method comprising:
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controlling a first node of said plurality to receive at least one signal communicated from a second node, and to calculate a response based on said signal; controlling said first node to calculate an auto-correlation function of said response, and to calculate an approximate peak value of a quadratic approximation based on said auto-correlation function; controlling said first node to determine a signal sampling phase offset between said response and said approximate peak value and in response, to calculate an actual peak value of said response; and controlling said first node to calculate an actual reception time for said at least one signal at said first node based on said actual peak value, and to determine, based on said actual reception time, a signal propagation time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 22)
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8. A system to determine signal propagation time between nodes in an ad-hoc communications network, said nodes being adapted to transmit and receive signals to and from other nodes in said ad-hoc network, the system comprising:
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a controller, adapted to control a first node of said plurality to receive at least one signal communicated from a second node, and to calculate a response based on said signal; said controller being further adapted to control said first node to calculate an auto-correlation function of said response, and to calculate an approximate peak value of a quadratic approximation based on said auto-correlation function; said controller being further adapted to control said first node to determine a signal sampling phase offset between said response and said approximate peak value and in response, to calculate an actual peak value of said response; and said controller being further adapted to control said first node to calculate an actual reception time for said at least one signal at said first node based on said actual peak value, and to determine, based on said actual reception time, a signal propagation time. - View Dependent Claims (9, 10, 11, 12, 13, 14, 23)
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15. A computer-readable medium of instructions, adapted to determine signal propagation time between nodes in an ad-hoc communications network, said nodes being adapted to transmit and receive signals to and from other nodes in said ad-hoc network, comprising:
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a first set of instructions, adapted to control a first node of said plurality to receive at least one signal communicated from a second node, and to calculate a response based on said signal; a second set of instructions, adapted to control said first node to calculate an auto-correlation function of said response, and to calculate an approximate peak value of a quadratic approximation based on said auto-correlation function; a third set of instructions, adapted to control said first node to determine a signal sampling phase offset between said response and said approximate peak value and in response, to calculate an actual peak value of response; and a fourth set of instructions, adapted to control said first node to calculate an actual reception time for said at least one signal at said first node based on said actual peak value, and to determine a signal propagation time based on said actual reception time. - View Dependent Claims (16, 17, 18, 19, 20, 21, 24)
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Specification