Asymmetric double-sided two-way ranging in an ultrawideband communication system
First Claim
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1. An asymmetric double-sided two-way ranging method using three messages, P1, P2, and P3, to complete a pair of round-trip delay measurements between a first device, A, having a first clock, Ca, and a second device, B, having a second clock, Cb, the method comprising the steps of:
- [1.1] in A, transmitting P1 at a selected point in time T0 relative to Ca;
[1.2] in B;
[1.2.1] after an unknown time-of-flight, Tf, receiving P1 at a time T1 relative to Cb; and
[1.2.2] after a first transmit delay, {circumflex over (D)}b, transmitting P2 at a time T2 relative to Cb;
[1.3] in A;
[1.3.1] after a first response delay, {circumflex over (R)}a, relative to T0, receiving P2 at a time T3 relative to Ca; and
[1.3.2] after a second transmit delay, {circumflex over (D)}a, transmitting P3 at a time T4 relative to Ca; and
[1.4] in B;
[1.4.1] after a second response delay, {circumflex over (R)}b, relative to T2, receiving P3 at a time T5 relative to Cb; and
[1.4.2] developing an estimate, {tilde over (T)}f, of Tf in accordance with a selected one of;
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Abstract
In an ultra-wideband (“UWB”) communication system comprising a pair of UWB transceivers, an asynchronous two-way ranging method for closely estimating the time-of-flight between the transceivers after the exchange of only 3 messages between the transceivers. In an alternate asynchronous two-way ranging method, the time-of-flight between the transceivers may be closely estimated after the exchange of only 4 messages between the transceivers.
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Citations
9 Claims
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1. An asymmetric double-sided two-way ranging method using three messages, P1, P2, and P3, to complete a pair of round-trip delay measurements between a first device, A, having a first clock, Ca, and a second device, B, having a second clock, Cb, the method comprising the steps of:
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[1.1] in A, transmitting P1 at a selected point in time T0 relative to Ca; [1.2] in B; [1.2.1] after an unknown time-of-flight, Tf, receiving P1 at a time T1 relative to Cb; and [1.2.2] after a first transmit delay, {circumflex over (D)}b, transmitting P2 at a time T2 relative to Cb; [1.3] in A; [1.3.1] after a first response delay, {circumflex over (R)}a, relative to T0, receiving P2 at a time T3 relative to Ca; and [1.3.2] after a second transmit delay, {circumflex over (D)}a, transmitting P3 at a time T4 relative to Ca; and [1.4] in B; [1.4.1] after a second response delay, {circumflex over (R)}b, relative to T2, receiving P3 at a time T5 relative to Cb; and [1.4.2] developing an estimate, {tilde over (T)}f, of Tf in accordance with a selected one of; - View Dependent Claims (2, 5, 6, 7, 8, 9)
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3. An asymmetric double-sided two-way ranging method using four messages, P1, P2, P3 and P4, to complete a pair of round-trip delay measurements between a first device, A, having a first clock, Ca, and a second device, B, having a second clock, Cb, the method comprising the steps of:
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[3.1] in A, transmitting P1 at a selected point in time T0 relative to Ca; [3.2] in B; [3.2.1] after an unknown time-of-flight, Tf, receiving P1 at a time T1 relative to Cb; and [3.2.2] after a first transmit delay, {circumflex over (D)}b, transmitting P2 at a time T2 relative to Cb; [3.3] in A; [3.3.1] after a first response delay, {circumflex over (R)}a, relative to T0, receiving P2 at a time T3 relative to Ca; [3.4] in B, transmitting P3 at a selected point in time T4 relative to Cb; [3.5] in A; [3.5.1] after an unknown time-of-flight, Tf, receiving P3 at a time T5 relative to Ca; and [3.5.2] after a second transmit delay, {circumflex over (D)}a, transmitting P4 at a time T6 relative to Ca; and [3.6] in B; [3.6.1] after a second response delay, {circumflex over (R)}b, relative to T4, receiving P4 at a time T7 relative to Cb; and [3.6.2] developing an estimate, {tilde over (T)}f, of Tf in accordance with a selected one of; - View Dependent Claims (4)
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Specification