A digital radio altimeter

Abstract

The invention discloses a digital radio altimeter and relates to the field of electronic technology. It is used to solve the problem that two altimeters are installed on each aircraft, and the altimeters affect each other, which will lead to wrong altimetry results and affect flight safety. The digital radio altimeter includes: a control and signal processing component, a radio frequency component and an antenna component; the radio frequency component forms a local oscillator signal with a switchable working frequency according to the frequency control signal; phase modulation is performed on the TTL pseudocode in sequence, and the local oscillator signal is carried out The first transmission signal is obtained by frequency mixing, and the power of the first transmission signal is adjusted according to the power control signal to obtain the second transmission signal, which is transmitted through the antenna assembly; the digital intermediate frequency signal corresponding to the second transmission signal is received through the antenna assembly, and the digital The intermediate frequency signal is sequentially processed by digital quadrature down-conversion and the code ring capture and tracking algorithm to obtain the code NCO 2 ; code NCO 2 The local code is generated by the second pseudo code generator, and the phase difference between the local code and the TTL pseudo code is compared to obtain a height value.

Description

technical field [0001] The invention relates to the field of electronic technology, and more specifically relates to a digital radio altimeter. Background technique [0002] According to the signal characteristics of the transmitted signal, the currently used radio altimeters can be divided into: frequency modulated continuous wave (FMCW) system, pulse system (PULSE) and pseudo code phase modulated continuous wave system. [0003] The FM continuous wave altimeter is a modulation signal in the form of a triangle wave, a sawtooth wave or a sine wave, which is added to a voltage-controlled oscillator to generate a high-frequency transmission signal with a large frequency range and the same variation law as the modulation signal. The antenna radiates to the ground, and the echo signal reflected from the ground enters the receiver through the receiving antenna, mixes with a part of the energy of the transmitted signal, and outputs a difference frequency signal containing height i...

AI Technical Summary

Problems solved by technology

[0008] The embodiment of the present invention provides a kind of digital radio altimeter, in order to solve the problem that two altimeters are installed on each aircraft in the prior art or when the aircraft fly in a team, because they all adopt the same working frequency and the same pseudo-code pattern, Mutual interference between altimeters will lead to wrong altimetry results and affect flight safety

Images