Abstract: A system and related method is disclosed for determining a range between a single antenna array and a surface. The system includes a source generator configured to generate a source signal, a coupler, a circulator, a mixer, and a digital signal processor. The source generator generates a frequency modulated continuous wave source signal. The coupler splits the source signal into a transmission signal and a coupled signal. The circulator receives the transmission signal from the coupler, outputs the transmission signal to an antenna, and receives a reception signal from the antenna, which may be a reflection of the transmission signal from the surface. The mixer mixes the reception signal from the circulator and the coupled signal from the coupler to generate a low frequency return signal. The digital signal processor determines a range between the antenna and the surface based on the low frequency return signal.

Abstract: A system and related method is disclosed for determining a range between a single antenna array and a radio-frequency reflective surface. The system includes a frequency modulated continuous wave (FMCW) signal generator which transmits the FMCW transmission signal through a pair of bias tees and a coupler prior to reaching a circulator. The circulator selectively routes the transmission signal to the single antenna array for transmission. As the transmission signal is reflected from the RF reflective surface, the single antenna array receives the reflected FMCW reception signal. The coupler receives the reception signal and delays and selectively routes the reception signal to a mixer which mixes the reception signal with a transmission signal input to create a low frequency signal. The low frequency signal passes through the pair of bias tees, is converted to digital, and received by a processor which determines the range to the reflective surface.

Abstract: The present disclosure is directed to low range altimeter (LRA) antenna implementations that are resistant to signal degradation under critical weather conditions. An altimeter may include a first antenna communicatively coupled to a transmitter configured to transmit a ranging signal to a surface. The altimeter may further include a second antenna communicatively coupled to a receiver configured to receive at least a portion of the ranging signal reflected from the surface. Each of the first (transmitting) antenna and the second (receiving) antenna may include a driven element and at least one parasitic director element. In some embodiments, at least a portion of an aircraft surface may function as a parasitic reflector element in accordance with a Yagi-Uda array antenna topology.