Design Of High Medium And Low Altitude Integrated Radio Altimeter

The radio altimeter is an important navigation equipment for aircraft and missiles.It can accurately measure the real height of aircraft relative to the ground or sea surface under various complex weather conditions,so as to ensure that the aircraft performs related tasks.The altimeter requirements of the different tasks,taking off and landing,need high precision low altitude information;airdrop control,aerial reconnaissance camera in high altitude information;terrain following avoidance,low altitude penetration requirements such as terrain contours altimeter has good characteristics in complex terrain;elevation range and high accuracy and has the good characteristics of the terrain contour line survey altimeter can not only meet the execution of the tasks of the vehicle height information needs and can solve the need to install multiple altimeter to both elevation range and high accuracy measurement problems,reduce the complexity of aircraft system and maintenance costs.Therefore,the research and design of altimeter with large range,high accuracy and small volume is very important.This paper first discusses the working principle of the pulse system altimeter,introduces the principle of altimeter signal detection and tracking and the principle of height calculation and gain control,and analyzes the altimetry range and measurement accuracy of the pulse system altimeter according to the radar equation.In this way,the performance requirements for each component are proposed.Secondly,this paper uses the random interpulse PPM and related accumulation techniques to adopt a two-way signal detection and tracking method different from the previous ones,effectively solving the same-frequency interference problem caused by the simultaneous work of multiple altimeters,and the altimetry error caused by large-angle flight.Grab the slope signal and the stable tracking problem of complex terrain.Finally,the paper completes the design of each component,the software design,test design and structural design of the whole machine;for the first time,the signal detection,tracking,height calculation,interface control,synchronous control,AGC control of the altimeter are integrated into one FPGA chip.In the above,the miniaturization design of the pulse altimeter is realized.Various tests validated the effectiveness of the design.