SU651285A1 - Vertical gradientometer - Google Patents

Description

one

A vertical gradiometer is used in inertial navigation and gravimetry.

A device for measuring the vertical component of the gravity of a gravity of gravity is known, which comprises a rocker arm attached to the torsion bar with masses at the ends fl.

It is practically very difficult to combine the center of gravity of the system with the axis of rotation with high accuracy, so the device responds not only to the vertical component of the gravity of gravity L, but also to the force of gravity. No measurement method and scale designs can separate the effect of L and gf. In addition, the center of gravity shifts due to temperature fluctuations, external vibrations, electrostatic forces, Hiibix convection currents and other external conditions.

These drawbacks do not allow.-Use of the considered device

For measuring A with high accuracy.

The purpose of the present invention is to improve the measurement accuracy.

This is due to the fact that

A second rocker and an engine with a horizontal shaft on which both rocker arms are attached are inserted into the vertical gradiometer; a pair of accelerometers is attached to the ends of each rocker arm, while the sensitivity axis of one accelerometer is directed along the rocker axis and the other one is the outputs of each pair of accelerometer

A ditch with the same directional sensitivity axes, but belonging to different rocker arms, is connected to the inputs of comparing devices, the output of which are connected to adders.

FIG. 1 depicts the proposed

gradiometer; in fig. 2 is a graph showing the operating principle of the proposed gradiometer. A radietitometer consists of body 1, rocker arm 2, accelerometers 3, 4, 5, 6, 7, 8, 9, 10, additional rocker arm 11, axis 12 of rotation, electric motor 13, comparing devices 14, 15, 16 17, totalizers 18, 19. and 1/2, and (Jj are the output signals of the comparison devices; -by the output signals of the summing devices. In the case 1, the shaft is installed horizontally 12. The shaft is connected to the rotor via the gearbox (or without it) Electromotor 13, the stator of which is rigidly fixed in the housing 1. On the shaft at point O, the rocker arm 2 and the additional arm are rigidly fixed o 11, perpendicular to each other and located in a plane perpendicular to the axis of rotation. At the ends of the rocker arm there are 3 pairs of accelerometers 3 and 4, 6 and 5, 8 and 7 1 and 9 (for example, strings), and the sensitivity axis of one of each pair accelerometers (3, 6, 8, 1О) are directed along the respective beam, and the sensitivity sensitivity of the second one from each lara of accelerometers (4, 5, 7, e) the first pair of comparing devices 17 and 15, respectively, and the output e signals Ak seleromegrov 4 and 9, 5, and 7 - on the second pair of comparators 16 and 14, respectively. The output signals U and Ui of the comparison devices 14 and 16, respectively, are fed to the summing device 18, the output signals It of the comparison devices 15 and 17, respectively, are fed to the summing device 19, the output signals of the summing devices 18 and 19 and contain information about the magnitude of the vertical component of the gravity of the gravity force L .. The principle of the proposed Rpaf radiation gauge is explained in FIG. 2, where the following symbols are taken; XQ Z © - cf; and inertial systems, coordinates; 0tff and X Z, X, Z are the axes of the coordinate system associated with the corresponding pair of accelerometers (for accelerometers sawn at the upper ends of the rocker arms). - acceleration of the force of gravity, - distance from the point of the fender of the rocker arms to the suspension centers of the sensitive accelerometers. When pavnomep rotate the shaft 12 at a speed on the axis of sensitivity X and 2 accelerometers 7 and 8 are designed acceleration d) er g cos-j -e, t; (1) d) g-2, - uinj- + et. Since the force of the weight Of, can be expressed in terms of the force of gravity at the point of attachment of the rockers and the vertex of the gravity force gradient D, at this point as follows gr eAsinj -go, then Expressions (1) take the form (2), Assuming that in the expression of t, the equations for a pair of accelerometers 5, 6 9x gfo TJ 3 2r-ef (5) are extra-2T In the output signals of accelerometers measuring the projections of accelerations by the formulas (2) and (3), contains both a useful signal varying with double speed 2 and interference. Subtracting expression (2a) from expression (2a) using comparing device 14, and likewise expression (36) from expression (26) with the help of comparing device 15, we obtain projection ratio E.G and J. Agy signals in which there is no constant the interfering component of e- and E gh eo ° t-1 t -D 21p2g,. eG2 on T-sov-ghz-lesob2 Further, to exclude from the output signals, the comparison devices 14 and 15, proportional to Ag and the interference signal varying with the rotational speed, use information from accelerometers 3, 4, 9, 10 converted with pomo. I compare .CHI.X devices 16 and 17 and having the ig-otc; o T ı 7 Å Aghin 27 5, Dgr 111T-c o57 D desob2 (g Equations (5) are obtained similar to equations (4). Processing signals proportional to D GL gx- efz

using the summing devices 18 and 19, respectively, we get signals

o, 2Ae51p2g;

(6)

BbiX2 2 tcos2T.

Thus, the opportunity is provided. the detuning of the useful signal from interference and associated with non-identical instruments and the difference B of different rocker arms. In addition, interference associated with slow processes (temperature effect, scab material relaxation, etc.) has virtually no effect.

The proposed gradiometer allows to achieve a high accuracy of measuring the vertical component of the gravity gradient force L, for example, when string accelerometers are used with a K 0 ZOO slope (accelerometer output signal is 50 Hz with an acceleration of 1 o) to measure the accuracy of DL l3TB. ejJJ 10 U, having chosen the modulation period T iOO s, it is necessary to measure the electric angle for the period T, equal to

M-Td to dL-3-0 padX.O..M.u This angle can be measured, for example, when the angle sensor is in the wiggle mode.

The proposed gradiometer is insensitive to accelerations with forced tilting and rotation axes with j- scopes, as well as to non-portable stresses arising from the base on which the device is installed (this follows from the analysis of

description of the movement of the device). This allows you to create a vertical, unperturbed by acceleration, for which you can add an additional control system to

Claims (1)

1. Veselov K. Ye., Sagitov M. U. Gravimetry intelligence, Moscow, Nedra 1968, p. 212. Ftp l and, Suxl nineteen / in "x2; /about //y.g