Radar altimeter simulator

摘要

An altitude simulator for checking the range accuracy of a radar altimeter is disclosed. Typical altimeters include a transmitter and a receiver. The simulator receives a multipulse trigger signal from the altimeter to be checked. The trigger signal is synchronized with the output pulses of the transmitter. This trigger signal forms an input to a phased locked loop to generate at the output of the phased locked loop a multipulse signal which is synchronized with and phase displaced from the trigger signal by an amount equal to the inherent time delays in the simulator. The output signal of the phase locked loop is coupled to the input of a pulse generator which is programmable to generate a multipulse output signal synchronized with and phase displaced from the output signal of the phase locked loop by a selected fixed amount. A modulator receives an RF input from a signal generator and the ouput signal of the pulse generator to produce at the output of the modulator a pulse modulated RF signal. This pulse modulated RF signal is coupled to the receiver as an input signal and is used to test and calibrate the altimeter.