Possibilities of Increasing the Low Altitude Measurement Precision of Airborne Radio Altimeters

Ján Labun,Alexey Nekrasov,Mária Gamcová,Pavol Kurdel,Marek Češkovič,Martin Krchňák

doi:10.3390/electronics7090191

Abstract

The paper focuses on the new trend of increasing the accuracy of low altitudes measurement by frequency-modulated continuous-wave (FMCW) radio altimeters. The method of increasing the altitude measurement accuracy has been realized in a form of a frequency deviation increase with the help of the carrier frequency increase. In this way, the height measurement precision has been established at the value of ±0.75 m. Modern digital processing of a differential frequency cannot increase the accuracy limitation considerably. It can be seen that further increase of the height measurement precision is possible through the method of innovatory processing of so-called height pulses. This paper thoroughly analyzes the laws of height pulse shaping from the differential frequency presented by the number that represents the information about the measured altitude for this purpose. This paper presents the results of the laboratory experimental altitude measurement with the use of a so-called double-channel method. The application of obtained results could contribute to the increase of air traffic safety, mainly in the phase of the aircraft approaching for landing and landing itself.

Highlights

High precision of a flight height measurement is required at low altitude, mainly in the phase of aircraft approaching for landing and landing
Experimental double-channel radio altimeter has been constructed in a laboratory with the use Experimental double-channel radio altimeter has been constructed in a laboratory with the use of two classical one-channel radio altimeters operating at the carrier frequency f 0 = 444 MHz with of two classical one-channel radio altimeters operating at the carrier frequency f0 = 444 MHz with the the frequency deviation ∆f = 17 MHz
The paper has presented a new possibility of increasing the measurement accuracy of small altitudes by airborne radio altimeters

Summary

Introduction

High precision of a flight height measurement is required at low altitude, mainly in the phase of aircraft approaching for landing and landing. For this purpose, an FMCW airborne radio altimeter (radar altimeter) is used for measuring the low altitudes [1]. When the flight height is measured, the principle of radiolocation with the evaluation of the time delay τ between the transmitted and received signal of a radio altimeter is used [2,3]. It can be presented that the flight altitude H directly corresponds to the delay of a received signal. The differential frequency is created between the immediate value of the Electronics 2018, 7, 191; doi:10.3390/electronics7090191 www.mdpi.com/journal/electronics

Methods

Results

Conclusion