SU1666991A1 - Carrier-borne device for measuring geomagnetic field - Google Patents

Abstract

The invention relates to a technique of magnetic measurements and is primarily intended for conducting marine magnetic surveys from the vessel’s carrier and radiation of the anomalous part of the geomagnetic field under the conditions of interference from geomagnetic variations, sea waves, carrier rolling, constant and variable magnetic fields created by the carrier itself, especially in cases where the magnitude of the interference exceeds the measured signal. The purpose of the invention is to improve the measurement accuracy by introducing the tensor component forming unit 10, the deviation correction unit 11, the carrier deviation meter 12, the integral component tensor unit 13, the tensor component correlation processing unit 14, the navigation correction unit 15, the integral navigation unit. system 16, timer 17, block 19 relative linear-angular corrections and meter 20 relative linear-angular displacements. The device also contains a meter component of the geomagnetic field, consisting of magnetically sensitive transducers 1 to 3, measuring blocks 4-6, analog-digital converters 7 to 9, an adder 18 and a recording device 21. 2 Il.

Description

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The invention relates to magnetic measurements and is primarily intended for conducting marine magnetic surveys from the carrier vessel and studying the anomalous part of the geomagnetic field in terms of interference from geomagnetic variations, sea waves, carrier rolling, constant and variable magnetic fields created by the carrier, especially in cases where the magnitude of the interference exceeds the measured signal.

The aim of the invention is to improve the measurement accuracy.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - location of sensors and measuring systems.

The device (Fig. 1) contains a meter component of the geomagnetic field, which includes magnetically sensitive transducers 1-3 (MCH), measuring units 4-6, analog-to-digital converters (ADC) 7-9, while the outputs of the ADC are connected to the input of block 10 forming the components of the tensor. To another input of the unit 10 is connected via a common bus the output of the block 11 of the deviation corrections associated with the meter 12 of the carrier deviation. The outputs of block 10 are connected to the inputs of block 13 of the integral values of the components of the tensor and block 14 of the correlation processing of the components of the tensor. At the same time, the output of the navigation correction block 15 connected to the integrated navigation system 16 is connected to another input of block 14. The outputs of blocks 10, 13, and 14 are connected to the input of adder 18 via a common bus to which timer 17 is connected. To another input of adder connected to the output of the block 19 relative linear-angle corrections associated with the meter 20 relative linear-angular displacements of the sensors. The output of the adder is connected with the registration device 21.

FIG. 2 points A (Mi), B (Ms), C (Me). D (M)

- vertices of the tetrahedron in which the magnetically sensitive transducers are located; F (M4) is the installation point of the vertical vertical and gyrocompass (integrated navigation system) and laser emitter; MI, Ma, Mo

- measuring points, i.e. vertices of the measuring triangle; Li, U. Ly - measuring rays of vertex B; La, Ls, Le - measuring rays of vertex C; Lj, LS - measuring vertices; Uo, Ln, Li2 - connecting rays of the measuring triangle; Lia. L 14 - measuring points of point F.

The device works as follows.

Three-component magnetically sensitive transducers 1-3, spatially separated in three coordinate axes, mounted on a movable carrier, interconnected by rigid bases, measure the geomagnetic field for each component at the installation site of each sensor and convert it to an electrical signal proportional to the measured field. The signal enters the measuring units of the magnetometer 4–6 and, after amplification and filtering in them, goes to analog-to-digital converters (ADC) 7–9, which represent this signal in digital form. From the outputs of the ADC, signals from both groups of three-component transducers for each component x, y, z are fed to a tensor component formation unit 10, which pairwise subtracts the field values for each component, forming a tensor consisting of nine gradient values of the geomagnetic field three os m:

Тх1-ТХ2, Txl-ТхЗ, Тх1-Тх4 ТУ1-Ту2, Ту1-Туз, Ту1-ТУ4 Tzl-TZ2. Tzi-Trz, TZ1-T74

To the other input of the tensor component forming unit 10, the deviation correction signals are sent from the deviation correction unit 11, associated with the carrier deviation meter 12.

In general, the connection of the component of the geomagnetic field tensor on a movable carrier in space-spaced sensors can be represented in video

Tk - Ti + (bk v) Ti + Dk, where Tic is the vector of the geomagnetic field at the point k ,, ,,

TI is the vector of the geomagnetic field at the starting point;

Dk - carrier deviation vector;

bkV is the direction vector of the magnetic axis of the sensor.

Since each measuring sensor is located at a different distance from the magnetic masses that determine the deviation of the vessel, there is a Die correction deviation at the location of each sensor.

Block 11 performs a synchronous sampling of the components of magnetic carrier deviation and recalculates them to the point of location of each sensor, from where they enter block 10, where they are subtracted from the generated values of the geomagnetic field gradients.

The signals from the output of block 10 enter the block 13 of the integral values of the components of the tensor, which integrates the values of the components of the tensor of the geomagnetic field over

In 1 time intervals equal to several periods of natural oscillations of the carrier.

The signals from the output of block 10 in parallel also arrive at block 14 of the correlation processing of the tensor components, where the signals of the tensor are processed according to the correlation characteristics simultaneously with the signals from the block 15 of navigation corrections associated with the integrated navigation system 16. The block of navigation corrections samples and recalculates the navigation components coming from the integrated navigation system measuring the angles of deflection of the carrier in three coordinates, in terms of corrections to the% measurements of the geomagnetic field by Multiplication navigation component size (scale) of the earth's magnetic field at the point of measurement.

Measured values can be represented as follows:

  T,

where B is the matrix of normalized coefficients of the directions of the magnetic axes of the sensors is

hn, hiz, hia

G121, h22. G123 P31. A32, h33

A gauge 20 of the relative linear angular movements of the sensors measures the dimensions of the bases between the sensors and the angular directions of the magnetic axes of each sensor.

The block 19 relative linear-angular corrections recalculates the corrections for linear-angular displacements of sensors to the field values for each component at the measurement site, after which they enter the input of adder 18. In the adder, these linear-angular corrections are algebraically summed (depending on the mode of operation of the device). ) or with measured values of the components of the geomagnetic field tensor (as amended by the deviation) (block 10), or with the results of correlation processing of the tensor components (with navigation corrections) (block 14) .

The operating mode of the proposed device is determined by the operating conditions, i.e. the level of interference created by the waves of the sea and the variable magnetic fields caused by these waves, namely, in the case of a calm sea and no interference, signals from the output of block 10 are sent to the input of the adder, in case of small waves and linear noise - from the output of block 13, and in the case of strong agitation and the appearance of nonlinear interference, from the output of block 14,

The operation of the entire device is synchronized with timer 20. It determines the moments of reading the signals from the measuring sensors in the gradient mode, forming the tensor gradients from these values, subtracting the deviation corrections from the readings of the measurement channels, and introducing navigation and linear-angle corrections.

A recording device 21 presents the results in the form of volumetric graphs (three three-dimensional graphs for each measurement region) or nine-component tables for each measurement region.

Three-component magchitus-sensitive transducers Mi, Ms. Mb, My are installed at the vertices of the tetrahedron A, B, C, D and are interconnected by rigid bases. In the points Mi, M2, and M3, the vertices of the measuring triangle also contain three-component MPPs, which form with the points Mi, Ms, Me. M is a gradiometric system along the axis X. Y. Z. The point F (M) is the installation point of the vertical axis and gyrocompass, which define the angular coordinates of the system, i.e. the direction of the vessel and its vertical deflection. At the same point is located the laser emitter, the rays of which are directed to the vertices of the tetrahedron. Each measuring point Mi, M2, M3 is associated with the other points by three laser beams, which allow triangulation to determine the mutual linear-angular displacements of each pair of three-component sensors. The laser source, which is rigidly connected to the tetrahedron, is additionally connected by rays to the hyper vertical, which makes it possible to measure the linear-angular displacements of the tetrahedron as a whole, relative to the vertical vertical.

Geomagnetic component meter

The field consists of 6 three-component channels, each of which consists of MPP, measuring blocks of magnetometers and ADC. As MCHP are used

fluxgate three-component sensors.

Claims (1)

Claims An apparatus for determining a geomagnetic field on a movable carrier, comprising a meter component of a geomagnetic field consisting of series-connected magnetically sensitive transducers, measuring units and analog-to-digital converters for each channel and series-connected adder and recording device, it is different in that, in order to improve the measurement accuracy, series-connected unit forming the component of the geomagnetic field tensor, unit of correlation processing the component of the tensor, unit integral are additionally introduced into it tensor component values, serially connected carrier deviation meter and deviation correction unit, serially connected integral navigation with Stem and navigation correction unit serially connected measuring linear and angular displacement sensors and block relative linear and angular adjustments as well as a timer, while one of the inputs forming unit the tensor component is connected to the outputs of analog-digital converters, another input is connected to the output of the deviation correction unit, the second output of the tensor component generation unit is connected through the integral value block of the tensor component with timer, the second input of the correlation processing component of the tensor component is connected to the adder, and the third input - to the output of the block of navigation amendments, and the output of the block of relative linear-angular corrections is connected to the second input of the adder. B / V FIG. 2