Frequency coherence within a location network
First Claim
1. A method of generating frequency coherence between a received reference positioning signal transmitted by at least one reference transmitter and a unique positioning signal generated by a positioning-unit device, said method comprising the steps of:
- a) receiving said reference positioning signal;
b) measuring the frequency offset of said received reference positioning signal relative to a common oscillator;
c) adjusting a frequency steerable clock by an amount derived from said measured frequency offset (b);
d) generating said unique positioning signal, wherein said unique positioning signal is aligned with said frequency steerable clock;
e) continuously adjusting said unique positioning signal by applying said measured frequency offset (b) to said frequency steerable clock, said frequency steerable clock referenced to said common oscillator;
such that the frequency of said adjusted unique positioning signal is aligned with the frequency of said reference positioning signal.
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Abstract
The present invention discloses a system and method of generating frequency coherence between a received reference positioning signal transmitted by at least one reference transmitter and a unique positioning signal generated by a positioning-unit device. A positioning-unit device is a specialized transceiver capable of receiving and interpreting reference positioning signals from the reference transmitter, another positioning-unit device or both. The positioning-unit device receives a reference positioning signal and measures a frequency offset in the received reference positioning signal relative to a common oscillator. Once a frequency offset is measured, the positioning-unit device adjusts a frequency steerable clock by an amount derived from the measured frequency offset. The positioning-unit device then generates a unique positioning signal, which is aligned with the frequency steerable clock. Furthermore, the positioning-unit device continuously adjusts said unique positioning signal by applying the measured frequency offset to the frequency steerable clock, which is referenced to the common oscillator. Subsequently, the frequency of the adjusted unique positioning signal is aligned with the frequency of the received reference positioning signal.
44 Citations
12 Claims
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1. A method of generating frequency coherence between a received reference positioning signal transmitted by at least one reference transmitter and a unique positioning signal generated by a positioning-unit device, said method comprising the steps of:
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a) receiving said reference positioning signal;
b) measuring the frequency offset of said received reference positioning signal relative to a common oscillator;
c) adjusting a frequency steerable clock by an amount derived from said measured frequency offset (b);
d) generating said unique positioning signal, wherein said unique positioning signal is aligned with said frequency steerable clock;
e) continuously adjusting said unique positioning signal by applying said measured frequency offset (b) to said frequency steerable clock, said frequency steerable clock referenced to said common oscillator;
such that the frequency of said adjusted unique positioning signal is aligned with the frequency of said reference positioning signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A positioning-unit device for generating frequency coherence between a received reference positioning signal transmitted by at least one reference transmitter and a unique positioning signal generated by said positioning-unit device, said positioning-unit device comprising:
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a) means for receiving said reference positioning signal;
b) means for measuring a frequency offset in said received reference positioning signal relative to a common oscillator;
c) means for adjusting a frequency steerable clock by an amount derived from said measured frequency offset (b);
d) means for generating said unique positioning signal, wherein said unique positioning signal is aligned with said frequency steerable clock;
e) means for continuously adjusting said unique positioning signal by applying said measured frequency offset (b) to said frequency steerable clock, said frequency steerable clock referenced to said common oscillator;
such that the frequency of said adjusted unique positioning signal is aligned with the frequency of said reference positioning signal. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification