Direction-determining system
First Claim
1. A direction-determining system comprising, in combination:
- a linear antenna array having at least first and second antenna elements, each for receiving an input signal from a Global Positioning System transmitter;
Global Positioning System receiver means includingsignal processing means for receiving said input signal from said linear antenna array and for converting it to an intermediate frequency signal, anda first phase-locked loop adapted to lock with the phase of the input signal received from said first antenna element and having a first output signal representative of the phase thereof;
a second phase-locked loop adapted to lock with the phase of the input signal received from said second antenna element and having a second output signal representative of the phase thereof;
synchronized switching means for selectively providing a first or second path from a selected said first or second antenna element to an input of said signal processing means and in synchronization therewith a third or fourth path from an output of said signal processing means to a corresponding said first or second phase-locked loop; and
means responsive to the phase difference between said phase locked loop output signals for determining the pointing angle of said linear antenna array,wherein said signal processing means includes a single radio frequency section,wherein each said selected one of said antenna elements is in intermittent electrical communication with its said corresponding phase-locked loop through said single radio frequency section andwherein said synchronized switching means functions sufficiently rapidly that each phase-locked loop remains locked to its said corresponding received input signal.
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Abstract
A direction determining system having a Global Positioning System (GPS) receiver, a linear antenna array and a fast switching facility, the linear antenna array comprised of at least two antenna elements and the GPS receiver including two Costas Loops. The fast switching facility permits an input signal received by the two antenna elements to be processed and alternately supplied to the Costas Loops in synchronism for measuring the phases of the input signals received nearly simultaneously. The phase difference between the output signals of the two Costas Loops is measured in a phase meter and the pointing angle of the linear antenna array relative to the direction of a GPS satellite is determined by interferometry.
45 Citations
7 Claims
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1. A direction-determining system comprising, in combination:
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a linear antenna array having at least first and second antenna elements, each for receiving an input signal from a Global Positioning System transmitter; Global Positioning System receiver means including signal processing means for receiving said input signal from said linear antenna array and for converting it to an intermediate frequency signal, and a first phase-locked loop adapted to lock with the phase of the input signal received from said first antenna element and having a first output signal representative of the phase thereof; a second phase-locked loop adapted to lock with the phase of the input signal received from said second antenna element and having a second output signal representative of the phase thereof; synchronized switching means for selectively providing a first or second path from a selected said first or second antenna element to an input of said signal processing means and in synchronization therewith a third or fourth path from an output of said signal processing means to a corresponding said first or second phase-locked loop; and means responsive to the phase difference between said phase locked loop output signals for determining the pointing angle of said linear antenna array, wherein said signal processing means includes a single radio frequency section, wherein each said selected one of said antenna elements is in intermittent electrical communication with its said corresponding phase-locked loop through said single radio frequency section and wherein said synchronized switching means functions sufficiently rapidly that each phase-locked loop remains locked to its said corresponding received input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification