Abstract: A low range altimeter (LRA) may include a transmitter, a receiver, at least one antenna, an active leakage cancellation circuit, and a microcontroller unit (MCU). The transmitter may be configured to transmit a first signal (or transmitted signal) via the at least one antenna. The receiver may be configured to receive a second signal (or received signal) via the at least one antenna. The active leakage cancellation circuit may be configured to receive a portion of the transmitted signal from the transmitter, and may be configured to inject the portion of the transmitted signal into the receiver after an adjustment of the portion of the transmitted signal to reduce leakage observed in the received signal. The MCU may be coupled to the transmitter and the receiver, and may be configured to adjust the portion of the portion of the transmitted signal.

Abstract: A low range altimeter (LRA) may include a transmitter, a receiver, at least one antenna, an active leakage cancellation circuit, and a microcontroller unit (MCU). The transmitter may be configured to transmit a first signal (or transmitted signal) via the at least one antenna. The receiver may be configured to receive a second signal (or received signal) via the at least one antenna. The active leakage cancellation circuit may be configured to receive a portion of the transmitted signal from the transmitter, and may be configured to inject the portion of the transmitted signal into the receiver after an adjustment of the portion of the transmitted signal to reduce leakage observed in the received signal. The MCU may be coupled to the transmitter and the receiver, and may be configured to adjust the portion of the portion of the transmitted signal.

Abstract: An altimeter apparatus for external fuselage mounting for an aircraft includes an altimeter circuit and a chassis. The altimeter circuit is coupled to an antenna system. The altimeter circuit is configured to generate a first signal and transmit the first signal via the antenna system, receive a second signal via the antenna system, wherein the second signal is a reflected version of the first signal, and determine an altitude based on the first and second signals. The chassis is configured to contain the altimeter circuit and the antenna system, wherein the chassis is connected to a fuselage of the aircraft and is located outside of the aircraft.

Abstract: A multi-function avionics system that includes, but is not limited to, a combined traffic collision avoidance system (TCAS) and directional measuring equipment (DME) system that utilizes a multi-function directional antenna for both functions. The multi-function system utilizes the same directional antenna for TCAS and DME functions, which typically utilize the same communication frequency band. The multi-function antenna may include four antenna elements that discriminate the direction of the DME ground station squitter. The DME system establishes a bearing to the ground station from the squitter and uses this information to determine which directional beam to use for the DME interrogation. Directional DME interrogation reduces the power requirements relative to that required for omni-directional DME interrogation. The integration of DME and TCAS enables the removal of antennas and feeder cables from the aircraft, saving weight, drag and cost.

Abstract: A first linearly polarized component of a signal is received. A second linearly polarized component of a signal is received, wherein the second linearly polarized signal component of a signal is orthogonal to the first linearly polarized component of a signal. The first linearly polarized component of a signal and the second linearly polarized component of a signal are down-converted to a lower frequency. A polarization correction is performed on the down-converted linearly polarized components.