Patent No. | 10,348,423 |
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Issue Date | July 09, 2019 |

Title | Calculating A Virtual Boresight Vector Of An Antenna Array |

Inventorship | Radivoje Zarubica, Salt Lake City, UT (US) Samuel C. Kingston, Salt Lake City, UT (US) Merle L. Keller, Salt Lake City, UT (US) |

Assignee | L3 TECHNOLOGIES, INC., New York, NY (US) |

17. An angle of arrival system comprising:an angle of arrival node having an antenna array and a modem coupled to the antenna array; and

a calibration node that is configured to emit a signal;

wherein the modem is configured to perform the following:

generate a first measured covariance matrix for the signal when the calibration node is positioned at an arbitrary location;

generate a second measured covariance matrix for the signal when the calibration node is positioned at a permanent location different from the arbitrary location;

generate a measured difference covariance matrix from the first and second measured covariance matrices;

determine an angle difference between an angle of the arbitrary location relative to the antenna array and an angle of the permanent location relative to the antenna array;

for each of a number of assumed angles of the permanent location relative to the antenna array:

calculate a first estimated covariance matrix for the assumed angle;

calculate a second estimated covariance matrix for a corresponding angle that is offset from the assumed angle; and

generate an estimated difference covariance matrix from the first and second estimated covariance matrices;

compare the measured difference covariance matrix to each estimated difference covariance matrix to identify one of the estimated difference covariance matrices that most closely matches the measured difference covariance matrix; and

calculate, from the assumed angle that corresponds with the identified estimated difference covariance matrix, an angle between the antenna array and the calibration node.

a calibration node that is configured to emit a signal;

wherein the modem is configured to perform the following:

generate a first measured covariance matrix for the signal when the calibration node is positioned at an arbitrary location;

generate a second measured covariance matrix for the signal when the calibration node is positioned at a permanent location different from the arbitrary location;

generate a measured difference covariance matrix from the first and second measured covariance matrices;

determine an angle difference between an angle of the arbitrary location relative to the antenna array and an angle of the permanent location relative to the antenna array;

for each of a number of assumed angles of the permanent location relative to the antenna array:

calculate a first estimated covariance matrix for the assumed angle;

calculate a second estimated covariance matrix for a corresponding angle that is offset from the assumed angle; and

generate an estimated difference covariance matrix from the first and second estimated covariance matrices;

compare the measured difference covariance matrix to each estimated difference covariance matrix to identify one of the estimated difference covariance matrices that most closely matches the measured difference covariance matrix; and

calculate, from the assumed angle that corresponds with the identified estimated difference covariance matrix, an angle between the antenna array and the calibration node.