Smart ground-terminal antenna for geostationary satellites in slightly inclined orbits
First Claim
1. A method for communication, comprising:
- providing an antenna system including a reflector having a focus and a feed array positioned at or near the focus and having N feed elements;
receiving N feed signals via the N feed elements, the N feed signals resulting from illumination of the N feed elements by a target signal incident on the reflector from a slow-moving signal source;
inputting the N feed signals to an N-to-N Fourier Transform device;
performing a spatial Fourier Transform on the N feed signals to generate N output signals, via the N-to-N Fourier Transform device;
computing a phase slope across the N output signals, via a correlation processor coupled to the N-to-N Fourier Transform device; and
determining a direction of arrival of the target signal based on the phase slope, via a direction-of-arrival processor coupled to the correlation processor.
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Accused Products
Abstract
A receive only smart antenna with a command pointing option for communicating with geostationary satellites that autonomously detects the directions from which desired signal are received, and steer the multiple beams accordingly. An array feed is used to illuminate a parabolic reflector. Each feed element of the receive only smart antenna is associated with a unique beam pointing direction. As a receiver is switched to different feed elements, the far-field beam is scanned, making it possible to track a geostationary satellite in a slightly inclined orbit. This eliminates the need for mechanical tracking and maintains high antenna gain in the direction of the geostationary satellite. The receive only smart antenna also features capabilities to form multiple simultaneous beams supporting operations of multiple geo-satellites in closely spaced slightly inclined orbits. The designs can support orthogonal beams for enhanced bandwidth capacity via multiple beams with excellent spatial isolation.
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Citations
20 Claims
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1. A method for communication, comprising:
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providing an antenna system including a reflector having a focus and a feed array positioned at or near the focus and having N feed elements; receiving N feed signals via the N feed elements, the N feed signals resulting from illumination of the N feed elements by a target signal incident on the reflector from a slow-moving signal source; inputting the N feed signals to an N-to-N Fourier Transform device; performing a spatial Fourier Transform on the N feed signals to generate N output signals, via the N-to-N Fourier Transform device; computing a phase slope across the N output signals, via a correlation processor coupled to the N-to-N Fourier Transform device; and determining a direction of arrival of the target signal based on the phase slope, via a direction-of-arrival processor coupled to the correlation processor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for communication, comprising:
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providing an antenna system including a reflector having a focus and a feed array positioned at or near the focus and having N feed elements; receiving N feed signals via the N feed elements, the N feed signals resulting from illumination of the N feed elements by a set of target signals incident on the reflector from respective slow-moving signal sources; inputting the N feed signals to an N-to-N Fourier Transform device; performing a spatial Fourier Transform on the N feed signals to generate N output signals, via the N-to-N Fourier Transform device; computing cross-correlations from the N output signals to generate a vector modifier, via a correlation processor coupled to the N-to-N Fourier Transform device; computing a phase slope across the N output signals for each of the target signals, via the correlation processor; determining directions of arrival of the respective target signals based on the respective phase slopes, via a direction-of-arrival processor coupled to the correlation processor; and generating, based on the vector modifier and the directions of arrival, beam weight vectors for respective beams associated with the respective directions of arrival, via the direction-of-arrival processor. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for communication, comprising:
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providing an antenna system including a reflector having a focus and a feed array positioned at or near the focus and having N feed elements; receiving N feed signals via the N feed elements, the N feed signals resulting from illumination of the N feed elements by a target signal incident on the reflector from a slow-moving signal source; inputting the N feed signals to a first N-to-N Fourier Transform device; performing a spatial Fourier Transform on the N feed signals to generate N output signals, via the first N-to-N Fourier Transform device; computing a phase slope across the N output signals, via a correlation processor coupled to the first N-to-N Fourier Transform device; and determining a direction of arrival of the target signal based on the phase slope, via a direction-of-arrival processor coupled to the correlation processor; generating a beam weight vector for a transmit beam associated with the direction of arrival; and applying the beam weight vector to a transmit signal to generate N element signals, via a digital beam forming processor. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification