Digital radio altimeter

Abstract

The invention discloses a digital radio altimeter, and relates to the technical field of electronics. The digital radio altimeter is disclosed in order to solve the problem that a wrong height measurement result will be caused and the flight safety will be affected due to mutual influence between two altimeters installed on each airplane at present. The digital radio altimeter comprises a controland signal processing assembly, a radio frequency assembly and an antenna assembly. The radio frequency assembly generates a local oscillation signal with switchable working frequency according to a frequency control signal; a first transmitting signal is obtained by carrying out phase modulation on a TTL pseudo code and mixing the TTL pseudo code with the local oscillation signal, the power of the first transmitting signal is adjusted according to a power control signal to obtain a second transmitting signal, and the second transmitting signal is transmitted through the antenna assembly; theantenna assembly receives a digital intermediate frequency signal corresponding to the second transmitting signal, and performs digital orthogonal down-conversion processing and a code loop capture tracking algorithm on the digital intermediate frequency signal in turn to obtain a code NCO2; and a local code is generated from the code NCO2 through a second pseudo code generator, and the phases ofthe local code and the TTL pseudo code are 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

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