초록 ▼

A single antenna FM radio altimeter operates in continuous wave (CW) and interrupted continuous wave (ICW) modes to provide an altitude indication. An altimeter transmitter generates a constant FM period CW signal below a critical altitude and a variable FM period ICW signal above the critical altit

A single antenna FM radio altimeter operates in continuous wave (CW) and interrupted continuous wave (ICW) modes to provide an altitude indication. An altimeter transmitter generates a constant FM period CW signal below a critical altitude and a variable FM period ICW signal above the critical altitude. The single antenna, connected to the transmitter and receiver, radiates and receives the CW and the ICW signals. The receiver provides a beat frequency signal. A processor compares the beat frequency signal and the variable FM period signal to critical altitude reference signals and switches the altimeter between the modes accordingly. The processing function provides the transmitter a constant period modulation signal below the critical altitude and a variable FM period signal above the critical altitude. The processing function provides the altitude indication from the beat frequency signal below the critical altitude and from the variable FM period signal above the critical altitude.

대표청구항 ▼

1. A FM radio altimeter with a single antenna capable of operating in a continuous wave mode and an interrupted continuous wave mode for providing an altitude indication comprising:a transmitter for generating a continuous wave altimeter signal below a critical altitude and an interrupted continuous

1. A FM radio altimeter with a single antenna capable of operating in a continuous wave mode and an interrupted continuous wave mode for providing an altitude indication comprising:a transmitter for generating a continuous wave altimeter signal below a critical altitude and an interrupted continuous wave altimeter signal above a critical altitude; a circulator connected to the transmitter for coupling the continuous wave altimeter signal and the interrupted continuous wave altimeter signal to the single antenna; the single antenna connected to the circulator for radiating the continuous wave altimeter signal and the interrupted continuous wave altimeter signal and receiving a reflected continuous wave altimeter signal and a reflected interrupted continuous wave altimeter signal; a receiver connected to the circulator for receiving the reflected continuous wave altimeter signal and the reflected interrupted continuous wave altimeter signal and providing an altimetric beat frequency signal therefrom; and a processing function for providing the transmitter a constant period modulation signal below the critical altitude and a variable FM modulation period signal above the critical altitude, for comparing the altimetric beat frequency signal and the variable FM modulation period to critical altitude references and for switching the altimeter between the continuous wave mode and the interrupted continuous wave mode in accordance with the comparison, and for providing the altitude indication.