Method and apparatus for estimating radar signal polarisation
First Claim
1. A method of estimating polarisation of an incoming electromagnetic signal, using an array of at least three differently directed detectors, each of which produces an output signal with a relationship of amplitude to direction of arrival of the incoming signal which differs for different polarisations of incoming signal, the method comprising the steps of:
- determining a first amplitude relationship of output signals of two adjacent detectors and a second amplitude relationship of output signals of two non-adjacent detectors, andestimating said polarisation of the incoming signal from the first and second amplitude relationships without reference to phases of the output signals.
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Abstract
This invention relates to a method and apparatus by which a coarse estimate of radar signal polarisation can be obtained. An array comprises at least three differently directed detectors. The polarisation is estimated by measuring an amplitude relationship, such as a ratio of amplitudes, for two adjacent detectors and for two non-adjacent detectors. This provides sufficient information to obtain a coarse estimate of the polarisation state, obtainable by using the value of the amplitude relationship for the two adjacent detectors together with a look-up table to estimate values of the amplitude relationship for the two non-adjacent detectors for different polarisation states, and then comparing the measured and estimated values for this amplitude relationship.
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Citations
12 Claims
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1. A method of estimating polarisation of an incoming electromagnetic signal, using an array of at least three differently directed detectors, each of which produces an output signal with a relationship of amplitude to direction of arrival of the incoming signal which differs for different polarisations of incoming signal, the method comprising the steps of:
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determining a first amplitude relationship of output signals of two adjacent detectors and a second amplitude relationship of output signals of two non-adjacent detectors, and estimating said polarisation of the incoming signal from the first and second amplitude relationships without reference to phases of the output signals. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for estimating polarisation of an incoming electromagnetic signal comprising:
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an array of at least three differently directed detectors, each of which produces an output signal with a variation of amplitude with direction of arrival of the incoming signal which differs for different polarisations of incoming signal, means for determining a first amplitude relationship of output signals of two adjacent detectors and a second amplitude relationship of output signals of two non-adjacent detectors, and means for estimating said polarisation of the incoming signal from the first and second amplitude relationships without reference to phases of the output signals. - View Dependent Claims (9, 10, 11, 12)
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Specification