The Design Of Pulsed Radio Altimeter Test Instrument

In the field of aviation, the radio altimeter is an altimetry instrument, which has been playing an increasingly important role. It can measure the height of aircraft relative to the ground, whose performance relates to the flight safety issue. Therefore, in order to ensure the normal work state of the radio altimeter, we need to develop a single test instrument, which can test and maintain the altimeter indoorsThe altimeter test equipment is designed as studying object according to the features of altimeter. It has three functions including Rf parameters measurement, delay response simulation, PC control communication,which is modular design method of hardware, realizing its design goal.Afterwards, basing on the functions of this test instrument needs and requirements indexes in subject, the dssertation explains the pulsed radio altimeter design scheme of testing instruments, including various hardware modules internal frame, the specific function of logic module circuit design and realization of the algorithm. The designing goal of subject focuses on Signal Processing Module, which is based on FPGA to realize. It carrries each function circuit design and implementation of the unit, finally completing to be controlled, and measured results analysis processing tasks.1) Completed signal conversion, demodulation, upconversion for RF input and output signal of variable frequency, and relaized the signal frequency to be mixing, attenuation, amplification;2) Completed the parameters of IF modulation signal and envelope signal to be measured, including frequency, power, pulse width and pulse period of the signal;3) Controlled the delay the response signal to output, and the delay time is wide and variable, to simulate a heigth of functionality for the measured altimeter equipment;4) Building a communication loop between the test equipment and PC, with the control software,and directly controlling and operating the test equipment, finally completing the each module of instrument and the machine commissioning and testing.