Robust low-frequency spread-spectrum navigation system
First Claim
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1. A method, comprising:
- receiving a ground-wave radiolocation signal at an antenna of a radiolocation receiver;
receiving a sky-wave radiolocation signal at the antenna of the receiver;
correlating the ground-wave radiolocation signal with the sky-wave radiolocation signal to determine a three-dimensional location of the receiver based on radiolocation data received from the ground-wave radiolocation signal and radiolocation data received from the sky-wave radiolocation signal; and
computing a height of the receiver from a differential delay figure between the sky-wave radiolocation signal and the ground-wave radiolocation signal.
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Abstract
Methods and apparatus are described for a navigation system. A process includes providing a plurality of transmitters distributed throughout a desired coverage area; locking the plurality of transmitters to a common timing reference; transmitting a signal from each of the plurality of transmitters. An apparatus includes a plurality of transmitters distributed throughout a desired coverage area; wherein each of the plurality of transmitters comprises a packet generator; and wherein the plurality of transmitters are locked to a common timing reference.
39 Citations
12 Claims
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1. A method, comprising:
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receiving a ground-wave radiolocation signal at an antenna of a radiolocation receiver; receiving a sky-wave radiolocation signal at the antenna of the receiver; correlating the ground-wave radiolocation signal with the sky-wave radiolocation signal to determine a three-dimensional location of the receiver based on radiolocation data received from the ground-wave radiolocation signal and radiolocation data received from the sky-wave radiolocation signal; and computing a height of the receiver from a differential delay figure between the sky-wave radiolocation signal and the ground-wave radiolocation signal. - View Dependent Claims (2, 3, 4)
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5. A method, comprising:
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receiving a ground-wave or a sky-wave spread spectrum radiolocation signal at a receiver; producing a correlation waveform with a series of narrow doublet pulses that correspond to transitions of a pseudorandom code associated with the spread spectrum radiolocation signal; applying the series of narrow doublet pulses to the spread spectrum radiolocation signal to obtain radiolocation information from the spread spectrum radiolocation signal; and determining a location of the receiver based on the radiolocation information. - View Dependent Claims (6, 7, 8, 9)
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10. A method, comprising:
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receiving a plurality of spread spectrum radiolocation signals at a receiver; determining a location of the receiver based on receipt of the plurality of spread spectrum radiolocation signals; rotating a directional antenna of the receiver to find a null in a directional pattern relative to a spread spectrum radiolocation signal of the plurality of spread spectrum radiolocation signals; and calculating a bearing of the receiver based on a position of the directional antenna when the null is detected. - View Dependent Claims (11, 12)
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Specification