SU1610275A1 - Barometric method of determining height - Google Patents

Abstract

The invention relates to the measurement of altitude and can be applied to determine the flight altitude of aircraft. The invention makes it possible to improve the accuracy of determining the height and simplify the calibration of the altimeter by achieving a linear dependence of the characteristic of the state of an elastic membrane-like solid body on height. The method consists in measuring the change in the characteristic of the state of an elastic membrane-like solid under the action of atmospheric pressure. The amplitude of mechanical vibrations is used as a state characteristic. At zero height, a membrane-like solid is excited at the frequency of the inflection of the resonance curve on a slope above the resonance frequency, the amplitude of the oscillations at zero height is measured, and the amplitude of the oscillations varies with the height at which the height is determined. 3 il.

Description

The invention relates to a technique for measuring altitude and can be applied to determine the altitude of flight of aircraft.

The purpose of the invention is to increase the accuracy of determining the height and simplify the calibration of the height gauge by achieving a linear dependence of the characteristic of the state of an elastic membrane solid from height.

FIG. 1 is a diagram of a barometric altimeter for carrying out the proposed method; FIG. 2 - normalized amplitude-frequency characteristics of the elastic membrane in FIG. 3 - experimental calibration of the height of the oscillations of the membrane.

The barometric altimeter contains an electrical sinusoidal voltage generator 1 and the electrostatic electrode 2 electrode of membrane oscillation 3. The membrane 3 is under the action of atmospheric pressure at a point, the height of which should be determined. Electrode 4 of the electrostatic converter allows measuring the changes in the amplitude of mechanical vibrations of the membrane 3. The signal from the electrode .4 enters the amplifier 5 and is indicated by the indicator 6. The power supply unit 7 provides the signal

setting of the operating point of electrostatic converters. The electrical high-resistance resistances R are charge, the capacitors C are separating. .

The method is carried out as follows.

At a pressure corresponding to zero height, using a sinusoidal electric voltage generator 1 of stabilized amplitude and electrode 2, excites membrane 3. Electrode 4, amplifier 5 and indicator 6 remove the amplitude-frequency characteristic 8 (Fig. 2) of membrane 3. Select the frequency f. at the inflection point of the resonance curve on a slope above the resonance frequency fn. When the height H changes, the resonance curve shifts (curve 9) and the amplitude of oscillations changes from Ad to Aj. This choice of operating frequency allows one to achieve a linear dependence of the amplitude of oscillations of the membrane on height as a result of compensation for the nonlinearity of the dependence of density on height and the nonlinearity of frequency versus density, as well as nonlinearity of the resonance curve. Equation pr my has the form

BUT

A „- JSC k-H,

AC - the amplitude of the mechanical vibrations of the membrane,

Hell - amplitude at zero height H O;

k is constant.

At the selected frequency f, the membrane is excited at a pressure corresponding to zero height Nd and view Hd Nd, the corresponding amplitudes of the Hell and AH of the oscillations are measured (Fig. 2). Based on these measurement results, indicator 6 is calibrated.

Increased accuracy is obtained due to the linearity of the relationship between the height and amplitude of oscillation of the membrane. This speeds up and simplifies calibration and increases height accuracy.

Claims (1)

Invention Formula An ethereal bar that is defined as the height at which vibrations of the elastic membrane are excited, measured and processed measurement results, characterized in that, in order to improve accuracy by reducing the effect of errors due to nonlinearity of the characteristic membranes, preliminarily at a pressure corresponding to zero height, excite membrane oscillations at a frequency greater than the resonance and corresponding to the linear portion of the resonance curve, and record their amplitude, and when they oscillate, they are recorded amplitude, and when processing the measurement results. the measured amplitude value and its value are taken into account at a pressure corresponding to zero height. FIG. one lt iKii L ", 5 v, o 3.3 0 2.5 2.0 / D X ./ ./ x X L X hourpot X x , /