Doppler beam-sharpened radar altimeter
First Claim
1. A method for Doppler beam sharpening in a radar altimeter, the method comprising:
- receiving a return signal at a radar altimeter receiver;
applying a first gate to the return signal to select at least a first component of the return signal;
performing spectral analysis on the first component of the return signal to generate a plurality of frequency bins, wherein each frequency bin is centered around a different frequency across a Doppler shift frequency spectrum for the first component of the return signal;
tracking the first component of the return signal;
selecting a first frequency bin of the plurality of frequency bins based on the Doppler shift frequency of the first component of the return signal; and
outputting a portion of the first component of the return signal falling within the first frequency bin for further processing.
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Accused Products
Abstract
Systems and methods for Doppler beam sharpening in a radar altimeter are provided. In one embodiment, a method comprises receiving a return signal at a radar altimeter receiver and applying a first gate to the return signal to select at least a first component of the return signal. Spectral analysis is performed on the first component of the return signal to generate a plurality of frequency bins, wherein each frequency bin is centered around a different frequency across a Doppler shift frequency spectrum for the first component of the return signal. The method further comprises tracking the first component of the return signal, selecting a first frequency bin of the plurality of frequency bins based on the Doppler shift frequency of the first component of the return signal, and outputting a portion of the first component of the return signal falling within the first frequency bin for further processing.
33 Citations
20 Claims
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1. A method for Doppler beam sharpening in a radar altimeter, the method comprising:
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receiving a return signal at a radar altimeter receiver; applying a first gate to the return signal to select at least a first component of the return signal; performing spectral analysis on the first component of the return signal to generate a plurality of frequency bins, wherein each frequency bin is centered around a different frequency across a Doppler shift frequency spectrum for the first component of the return signal; tracking the first component of the return signal; selecting a first frequency bin of the plurality of frequency bins based on the Doppler shift frequency of the first component of the return signal; and outputting a portion of the first component of the return signal falling within the first frequency bin for further processing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A Doppler beam-sharpened radar altimeter, comprising:
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a processor generating a range gate, wherein the range gate tracks a first component of the return signal; a spectral analyzer performing spectral analysis on a return signal to generate a plurality of frequency bins, wherein each frequency bin is centered around a different frequency in a Doppler shift frequency spectrum; a selector selecting a frequency bin for further processing; and a power management circuit (PMC) for; detecting the signal strength of the return signal; and maintaining the signal strength of the return signal at an approximately constant level by varying the transmit power of a transmitted signal. - View Dependent Claims (11, 12, 13, 14)
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15. A Doppler beam-sharpened radar altimeter, comprising:
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a receiver for receiving a return signal; and a track channel communicatively coupled to the receiver, wherein the track channel comprises; a first gating circuit that generates a range gate, wherein the range gate tracks the return signal; a track processor, wherein the track processor applies a windowing scheme to the return signal; a first spectral analyzer that generates a first plurality of frequency bins corresponding to a Doppler shift frequency spectrum of the return signal; and a first selector that selects a first frequency bin of the first plurality of frequency bins based on the Doppler shift frequency of a first component of the return signal. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification