Geographical navigation using multipath wireless navigation signals
First Claim
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1. A method of navigating using a multipath wireless signal, the method comprising the steps of:
- providing navigation information indicative of a geographical location;
receiving a multipath navigation signal;
relating the multipath signal to the geographical location; and
navigating using the multipath signal based on the relationship.
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Abstract
A wireless navigational system and process utilize multipath wireless signals normally discarded from the navigation solution to enhance navigational performance under a range of operational scenarios. A relationship between the receiver'"'"'s location and one or more multipath signals is established, facilitating subsequent navigation using the multipath signal(s).
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Citations
31 Claims
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1. A method of navigating using a multipath wireless signal, the method comprising the steps of:
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providing navigation information indicative of a geographical location;
receiving a multipath navigation signal;
relating the multipath signal to the geographical location; and
navigating using the multipath signal based on the relationship. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
determining a first path delay, corresponding to a direct-path distance to the wireless, source multiplied by a propagation velocity; and
determining a second path delay, corresponding to a multipath distance to the wireless source, multiplied by the propagation velocity, the multipath parameters being related to the first and the second path delays.
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6. The method of claim 5 wherein the step of determining a path delay comprises the steps of:
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Time shifting a replica of a received signal;
correlating the received signal with the time-shifted replica thereof; and
determining a time-shift value resulting in a relative maximum correlation of the received signal with the time-shifted stored representation of the received signal.
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7. The method of claim 2 wherein the direct-path wireless navigation signal is transmitted according to a wireless network protocol.
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8. The method of claim 7 wherein the wireless network protocol is a Bluetooth protocol.
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9. The method of claim 1 wherein the navigation information is provided by a direct-path wireless navigation signal transmitted from a wireless source, the relating step comprising shifting the direct-path signal and correlating the shifted direct-path signal with the multipath signal.
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10. The method of claim 1 wherein the navigation information is provided by a known starting location and an estimation of a current location based on the starting location.
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11. The method of claim 1 wherein the navigation information comprises general location information.
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12. The method of claim 1 wherein the wireless multipath signal is generated by a Global Positioning System (GPS) transmitter.
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13. An apparatus for navigating using a multipath wireless signal, the apparatus comprising:
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circuitry for providing a geographical location;
a receiver receiving a wireless multipath navigation signal;
circuitry for relating the multipath signal to the geographical location; and
circuitry for navigating using the multipath signal based on the relationship. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
circuitry for determining a first path delay corresponding to a direct-path distance to the wireless source multiplied by a propagation velocity; and
circuitry for determining a second path delay corresponding to a multipath distance to the wireless source multiplied by the propagation velocity, the multipath parameters relating the first path delay to the second path delay.
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26. The apparatus of claim 25 wherein the circuitry for determining the first and second path delays comprises:
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circuitry for time shifting a stored representation of a received signal;
circuitry for correlating the received signal with the time-shifted stored representation thereof; and
circuitry for determining a time-shift value corresponding to a relative maximum correlation of the received signal with the time-shifted stored representation of the received signal.
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27. The apparatus of claim 26 wherein the time-shifting circuitry comprises a delay device providing a delayed output.
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28. The apparatus of claim 27 wherein the delay device comprises a tapped-delay line.
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29. The apparatus of claim 27 wherein the delay device comprises a shift register.
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30. The apparatus of claim 21 wherein at least one of the multipath signal and the direct-path signal is of insufficient strength to permit navigation based thereon, the navigation circuitry comprising circuitry for combining the received multipath signal and the received direct-path signal to provide a navigation solution.
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31. The apparatus of claim 13 wherein the geographical-location circuitry determines the geographical location from a known starting location and an estimation of a current location based on the starting location.
Specification