The new approach of evaluating differential signal of airborne FMCW radar-altimeter

Sotak, Milos; Labun, Ján

doi:10.1016/j.ast.2011.02.007

Cited by 10 publications

(14 citation statements)

References 2 publications

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“…The instant value of the difference frequency F d (as a low-frequency information signal of the measured altitude H) is made by the time delay τ of the received signal frequency f R against the transmitted signal frequency f T . The delay of the received signal is created by overpassing the height difference on the aircraft-ground-aircraft route [3,4]. Such a radio altimeter possesses its methodological error of height measurement ±∆H, which is based on the physical fundamentals of of evaluation of the differential frequency.…”

Section: Introductionmentioning

confidence: 99%

“…Such a radio altimeter possesses its methodological error of height measurement ±∆H, which is based on the physical fundamentals of of evaluation of the differential frequency. The methodological error is determined by a so-called critical height ∆H, which is the minimal height range that a radio altimeter can distinguish [4]. The value of the critical height is determined by the following equation:…”

Section: Introductionmentioning

confidence: 99%

“…Previously, we have proposed some methods to increase the accuracy of altitude measurement by radar altimeters. A new method for measuring the altitude by estimating the period of the differential frequency is presented in [4]. This method does not have a methodological error and provides better measurement accuracy, especially at low altitude, in comparison with the currently used method that is based on the classical calculation of height pulses.…”

Section: Introductionmentioning

confidence: 99%

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Low Altitude Measurement Accuracy Improvement of the Airborne FMCW Radio Altimeters

et al. 2019

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This manuscript focuses on the analysis of a critical height of radio altimeters that can help for the development of new types of aeronautical radio altimeters with increased accuracy in measuring low altitudes. Altitude measurement accuracy is connected with a form of processing the difference signal of a radio altimeter, which carries information on the measured altitude. The definition of the altitude measurement accuracy is closely linked to the value of a critical height. Modern radio altimeters with digital processing of a difference signal could shift the limit of accuracy towards better values when the basics of the determination of critical height are thoroughly known. The theory results from the analysis and simulation of dynamic formation and the dissolution of the so-called stable and unstable height pulses, which define the range of the critical height and are presented in the paper. The theory is supported by a new method of derivation of the basic equation of a radio altimeter based on a critical height. The article supports the new theory of radio altimeters with the ultra-wide frequency deviation that lead to the increase the accuracy of a low altitude measurement. Complex mathematical analysis of the dynamic formation of critical height and a computer simulation of its course supported by the new form of the derivation of the basic equation of radio altimeter guarantee the correctness of the new findings of the systematic creation of unstable height pulses and the influence of their number on the altitude measurement accuracy. Application of the presented findings to the aviation practice will contribute to increasing the accuracy of the low altitude measurement from an aircraft during its landing and to increasing air traffic safety.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low Altitude Measurement Accuracy Improvement of the Airborne FMCW Radio Altimeters

et al. 2019

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“…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].…”

Section: Introductionmentioning

confidence: 99%

“…The critical altitude is also connected with the radio altimeter measurement accuracy ±∆H. It is possible to derive mathematically that the critical altitude depends on the frequency deviation of a transmitted high-frequency signal according to the following formula [3].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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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.

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A blind spot detection and warning system based on millimeter wave radar for driver assistance

Liu

Ming-zheng

Wang

et al. 2017

Optik

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The new approach of evaluating differential signal of airborne FMCW radar-altimeter

Cited by 10 publications

References 2 publications

Low Altitude Measurement Accuracy Improvement of the Airborne FMCW Radio Altimeters

Low Altitude Measurement Accuracy Improvement of the Airborne FMCW Radio Altimeters

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

A blind spot detection and warning system based on millimeter wave radar for driver assistance

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