Dual base line interferometer antenna
First Claim
1. A radar system for passively detecting and tracking targets, wherein said system does not have its own transmitting source, comprising:
- a signal transmitting source-of-opportunity detached from and unassociated with the remainder of said system except as a signal supply;
a target illuminable by said source;
a plurality of interferometer antennas for receiving a signal directly from said source and a signal reflected from said target wherein the signals received at each interferometer antenna will have a relative phase relationship;
means for measuring the relative phase difference between signals received by said antennas; and
means for converting said relative phase difference into an angle value indicating the directional location of said target from said system.
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Abstract
A radar system for determining the position of a target using a radio frency source of opportunity. The system uses an interferometer antenna and cross-correlation techniques to measure the time delay in receiving a reflected signal from the target as compared to receiving a direct signal from the signal source. Thereby, the distance from the RF source via the target to the antenna is determined. Additionally, the system uses a plurality of interferometer antennas and cross-correlation techniques to measure the relative phase difference between the signals received by the antennas. Thereby the angle of arrival of the reflected signals from the target is determined. Combining the range and angular information locates the target.
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Citations
6 Claims
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1. A radar system for passively detecting and tracking targets, wherein said system does not have its own transmitting source, comprising:
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a signal transmitting source-of-opportunity detached from and unassociated with the remainder of said system except as a signal supply; a target illuminable by said source; a plurality of interferometer antennas for receiving a signal directly from said source and a signal reflected from said target wherein the signals received at each interferometer antenna will have a relative phase relationship; means for measuring the relative phase difference between signals received by said antennas; and means for converting said relative phase difference into an angle value indicating the directional location of said target from said system. - View Dependent Claims (2, 3, 4, 5)
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6. A method of passively detecting and tracking a target comprising;
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receiving signals directly from a radio frequency transmitting source-of-opportunity, receiving signals reflected from a target illuminated by signals from said transmitting source-of-opportunity, comparing a first set of said direct and reflected signals with a second set of said direct and reflected signals in order to measure the relative phase difference between said sets, and converting said relative phase difference into an angle value for indicating the direction from the receiver to the target.
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Specification