Garmin International, Inc.

Edward W Needham

John C Blessing

David T Mindrup

Weiguang Hou

A system and method are provided for estimating bearing of a target based on RF signals received by an array of antenna elements. The system comprises first and second input channels that are configured to receive analog signals that correspond to first and second antenna elements. The system also includes an analog to digital converter module for converting each of the analog signals to digital data samples and outputting separate streams of digital data samples corresponding to each of the first and second antenna elements as first and second data streams. An in-phase and quadrature detector module includes a phase shift module for shifting each of the first and second data streams by a predetermined amount of time to form first and second phase shifted data streams. A surveillance module determines a bearing of the target based on in-phase and quadrature data.

Methods and systems for frequency independent bearing detection

In accordance with one aspect of the present invention, a method is provided for calibrating an aircraft surveillance system for a protected aircraft. The system has a phased antenna array comprising antenna elements. The method comprises transmitting a first signal from a first antenna element in the array, and receiving the first signal at a third antenna element. The first signal may represent an interrogation signal transmitted in connection with a surveillance transmit sequence to locate potential intruding aircraft into a range of the protected aircraft. The method further includes transmitting a second signal from a second antenna element and receiving the second signal at the third antenna element. The method also includes calculating calibration information for the antenna array based on the first and second signals received at the third antenna element. During each transmit operation only a single antenna element transmits at one point in time.

Method and system for calibrating an antenna array for an aircraft surveillance system

An active antenna is provided that includes an antenna element for transmitting RF transmit signals at a predetermined effective radiated power (ERP). An antenna module is configured to be mounted to an aircraft, with the antenna element being mounted to the antenna module. A connector module is provided at the antenna module and is configured to be coupled to a communications link and receive electrical transmit signals from the communications link. A transmit path is provided within the antenna module and extends between the antenna element and the connector module. A power amplifier is provided on the antenna module along the transmit path. The power amplifier increases a power level of the electrical transmit signals, received from the communications link, by a predetermined amount sufficient to drive the antenna element to transmit the RF transmit signals at the predetermined ERP.

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Wellsville, KS, United States of America

Edward W Needham