RU2075097C1 - Process of magnetometric prospecting from mobile search craft - Google Patents

Abstract

FIELD: navigation, geomagnetic measurements from flying vehicle. SUBSTANCE: in process of pre-start preparation sensitive axes of three-component magnetometer are fixed relative to construction lines of flying vehicle. Levelled flying vehicle is set in two course positions, then within them into one unspecified bank position, further on flying vehicle is levelled again and turned with constant angular speed along course, then flying vehicle is levelled again and turned with constant angular speed along bank. Projections of resulting magnetic field on to construction lines of flying vehicle are measured in same spatial positions of flying vehicle as well as angles of pitching and bank courses. Angle speed of turn through angles of course and bank during turns of flying vehicle are also measured. Vortex component of inherent magnetic field of flying vehicle is found by obtained results. Horizontal and vertical components of geomagnetic field are determined with allowance or value of vortex component of inherent magnetic field in process of flight of flying vehicle along specified route. EFFECT: expanded application field of proposed process. 1 dwg

Description

 The invention relates to the field of navigation, can be used to improve the accuracy of geomagnetic measurements from a moving object, for example, an aircraft (LA).

A known method of magnetometric reconnaissance from a mobile search apparatus, in which, in the process of moving the search apparatus along a given route, the horizontal and vertical components of the geomagnetic field are measured [1]
The disadvantage of this method is the low accuracy of determining the components of the geomagnetic field, due to variable deviation coefficients during the evolution of the aircraft.

 The invention solves the problem of increasing the accuracy of determining the components of the geomagnetic field.

The problem is solved by the fact that the proposed method of magnetometric reconnaissance from a mobile search engine, in which the horizontal and vertical components of the geomagnetic field are measured while the search engine moves along a given route, and before that, preliminary preparation is carried out, during which the measuring axes of the three-component magnetometer are fixed relative to construction axes of the search apparatus, set the horizontal search apparatus sequentially in d and the exchange rate at the angle position 0 ^o and 90 ^o, AZAT at an angle 0 ^o the course search unit is set to one arbitrary position on the roll angle (10 ^o .45 ^o), the search apparatus further gorizontiruyut and unfold it again at a constant angular velocity by heading from 0 ^o to 90 ^o , and then at a heading angle of 0 ^o, deploy a search apparatus with a constant angular roll speed from 0 ^o to 45 ^o , and in each of these spatial positions of the search apparatus, projections of the resulting magnetic field on the building axes of the apparatus are measured, as well as the angles of the course, pitch and roll, and during the turns of the search apparatus also the angular speeds of the turn in the corners of the course and roll, according to the obtained measurement results find the vortex component of the intrinsic magnetic field of the search apparatus, and in the process of moving the search apparatus along a given route, the horizontal and vertical components of the geomagnetic field determined taking into account the magnitude of the vortex component of the intrinsic magnetic field of the search apparatus.

 New in the proposed method is that in the process of pre-launch preparation according to the proposed actions and procedures for the search apparatus according to the developed algorithms, the vortex component of its own magnetic field is determined, taking into account which during the movement of the apparatus along the route allows us to determine the horizontal and vertical components of the geomagnetic field.

 The drawing shows a structural diagram of a device for implementing the inventive method.

The device for implementing the method comprises a block of three orthogonal magnetometers 1 mounted without a cardan suspension on the object’s body, for measuring the longitudinal Tx, transverse Tz and normal Tu components of the intensity vector of the resulting magnetic field of the object on the axis of the associated coordinate system ОХУЗ; a gyroscope of direction 2 for determining the gyroscopic course ψ _{g of a} moving object; vertical gyro 3 for determining roll angles γ and pitch n of a moving object; the first 4 and second 5 differentiating devices for differentiating the gyroscopic heading signal j _g and the angle of heel γ, respectively; the first calculator 6 for determining the coefficients of the vortex component of the magnetic field of the object, an integrator 7 for determining the projections of the vector of the geomagnetic field intensity on the axis of the coordinate system associated with the object; a second calculator for determining the horizontal and vertical components of the geomagnetic field intensity vector during magnetometric reconnaissance. The outputs of block 1 are connected to the inputs of the first calculator 6, integrator 7 and the second calculator 8. The output of block 2 is connected to the input of the first differentiating device 4, the first calculator 6 and integrator 7. The outputs of block 3 at angles g and n are connected to the inputs of the integrator 7 and second of the calculator 8 and additionally in angle g with the inputs of the second differentiating device 5 and the first calculator 6. The outputs of the first 4 and second 5 differentiating devices are connected to the inputs of the first calculator 6. At the inputs of the first calculator 6 are fed, in addition, a manual exhibition ntsiometer (or controller) starting values of the horizontal and vertical components of the geomagnetic field intensity vector, measured, for example, using a deflector and an inclinator; as well as the inputs of the first calculator 6 and integrator 7, from a potentiometer of a manual exhibition (or controller), pre-determined Poisson parameters (a, k) and components of a constant magnetic field (P, Q, R) of the aircraft are introduced. The output of the first computer 6 is connected to the input of the integrator 7, the output of which is connected to the input of the second computer 8.

где

T_M [T_xgT_ygT_zg]^T; T_П [PQR]^T;
T_Э T_XЭT_УЭT_ZЭ]^T; знак "Т" обозначает транспонирование.The relationships for determining the horizontal and vertical components of the geomagnetic field intensity vector are based on the following theoretical positions. The mathematical model of the magnetic field at the object (MPO) is described by the Poisson equations [3]

Where

T _M [T _xg T _yg T _zg ] ^T ; T _P [PQR] ^T ;
T _E T _XE T _UE T _ZE ] ^T ; the “T” sign stands for transposition.

In (1) (2) the following notation is accepted:
S Poisson's matrix, coefficients a, b, k characterize the inductive component of the MPO;
F matrix of coefficients a ₁ , b ₁ , k ₁ characterizing the vortex component of the MPO;
E is a unit matrix of size 3 x 3;
A matrix of directional cosines characterizing the orientation of a moving object (PO) relative to the geographic normal accompanying trihedron ohgygzg (right orthogonal trihedron OXYZ, in which OX, OY, OZ are the longitudinal, normal and transverse axes of the object, with the OZ axis pointing to the starboard side; oxgygzg right orthogonal trihedron, in which the OXg axis is directed to the geographical North, the OYg axis is vertical; the OZg axis is directed to the East);
Tx, Ty, Tz components of the vector of tension of the resulting MPO along the axes of the object;
Тxg, Tyg, Tzg components of the geomagnetic field intensity vector along the corresponding axes;
P, Q, R components of the vector of the constant component of the MPO along the axes OX, OY, OZ, respectively;
T _xE , T _yE , T _{zE are the} components of the electromagnetic component of the MPO tension vector along the corresponding axes.

(T_x, T_y, T_z) с помощью трехкомпонентного блока магнитометров, а также с помощью трехкомпонентной гироскопической системы гироскопа направления и гировертикали измеряются углы ориентации ПО (формируется матрица А).In further calculations, we will neglect the component T _Э , assuming that at the installation point of the magnetometer on board the object due to a number of measures it is practically zero. Regarding equation (1), it is assumed that T and A are known at each moment of time, since the vector is continuously measured on board

(T _x , T _y , T _z ) using the three-component block of magnetometers, as well as using the three-component gyroscopic system of the directional gyroscope and vertical gyro, the orientation angles are measured (matrix A is formed).

 The main task of on-board magnetometric measurements for navigation, geophysics and geology is the task of determining the geomagnetic field strength vector both in the coordinate system associated with the object and in the geographical coordinate system. Obviously, the higher the accuracy of determining the northern, eastern and vertical components of the geomagnetic field, the more accurately you can determine its anomalies and make corrections to your own location or assess the presence of either minerals or objects of artificial origin.

в памяти бортового цифрового вычислительного устройства. Приведены алгоритмы идентификации матриц S и T_n, то есть алгоритмы определения параметров Пуассона (а,к) и компонент постоянной составляющей МПО (Р, Q, R).The task of determining the geomagnetic field with high accuracy cannot be solved without knowledge of the MPO. Analytically, this reduces to defining the matrices F, S, and T _n . The problem of identifying MPO in the sense of determining the matrices S and T _n using the direct method of parametric identification of static and dynamic systems was solved, for example, by expanding the state vector of system (1) to a dimension that coincides with the number of identifiable parameters. The expansion was carried out due to discretization of the measurement process in time during software motion and fixing the measurement results of the vector components

in the memory of the on-board digital computing device. Algorithms for identifying the matrices S and T _n are presented, that is, algorithms for determining the Poisson parameters (a, k) and the components of the constant component of the MPO (P, Q, R).

In further calculations, it is also assumed that the matrices S and T _n on board the software are already identified and the Poisson parameters (a, k), as well as the components of the constant component of the MPO (P, Q, R) are known.

 From equation (1) we obtain the identification algorithms for the matrix of the vortex component of MPO F.

 Assume that the aircraft was pre-installed on the deviation site in several fixed angular positions along the course, and then turned around at a constant angular velocity, and in the same angular positions in both cases the readings of the three-component magnetometer were recorded.

Производя вычитание от уравнения (4) уравнения (3) при одних и тех же значениях углов (параметров матрицы А), получим

где

разность показаний магнитометров ЛА (6)
Дополнительно предположим, что ЛА горизонтирован (т.е. ∠ν = ∠γ = 0 и разворот ЛА осуществляется вокруг вертикальной оси с постоянной угловой скоростью

сonst. C учетом этого (5) примет следующий вид:

где с сos, s sin соответственно.For fixed angular positions, taking into account the previously accepted assumptions, equation (1) takes the form
T ₁ (S + E) • A • T _M + T _P (3)
When cornering, we will have

Subtracting equation (3) from equation (4) for the same values of the angles (parameters of matrix A), we obtain

Where

difference between the readings of the LA magnetometers (6)
Additionally, we assume that the aircraft is horizontal (i.e., ∠ν = ∠γ = 0 and the aircraft is rotated around the vertical axis with a constant angular velocity

const. With this in mind, (5) will take the following form:

where с cos, s sin, respectively.

Отсюда при

получаем следующие соотношения для определения параметров матрицы F C₁, f₁, k₁

а при ψ=90^° 90^o получаем следующие соотношения для определения параметров матрицы F a₁, d₁, g₁:

Оставшиеся параметры матрицы F находятся при следующих угловых положениях ЛА: допустим, что ЛА горизонтирован (ψ=0^°; ν=0^°; γ=0^°) и предварительно устанавливался на девиационной площадке в нескольких фиксированных угловых положениях по крену, а затем разворачивался с постоянной угловой скоростью

, где t время) и в тех же угловых положениях в обоих случаях фиксировались показания трехкомпонентного магнитометра ЛА. Поступая аналогично выполненному ранее, производя вычитание сигналов магнитометров и соответственно полученных уравнений при одних и тех же параметрах матрицы угловой ориентации А, в итоге получим:

отсюда имеем:

В итоге при определенных ранее параметрах a₁, d₁, g₁, с₁, f₁ k₁ и при sγ=0,2...0,5 имеем следующие соотношения для определения параметров b₁, e₁, h₁ матрицы вихревой составляющей МПО F:

Следует отметить, что если при разворотах ЛА затруднительно обеспечить постоянство угловых скоростей разворота

, то необходимо использовать усредненные значения:

и использовать их в ранее полученных соотношениях вместо текущих значений угловых скоростей.Performing the transformations in (7), we obtain

From here when

we obtain the following relations for determining the parameters of the matrix FC ₁ , f ₁ , k ₁

and at ψ = 90 ^° 90 ^o we obtain the following relations for determining the parameters of the matrix F a ₁ , d ₁ , g ₁ :

The remaining parameters of the matrix F are found at the following angular positions of the aircraft: suppose that the aircraft is horizontal (ψ = 0 ^° ; ν = 0 ^° ; γ = 0 ^° ) and pre-installed on the deviation pad in several fixed angular positions along the roll, and then deployed with constant angular velocity

, where t time) and in the same angular positions in both cases the readings of the three-component magnetometer of the aircraft were recorded. Acting similarly to what was done earlier, subtracting the signals of the magnetometers and, accordingly, the obtained equations for the same parameters of the matrix of the angular orientation A, as a result, we obtain:

from here we have:

As a result, with the previously defined parameters a ₁ , d ₁ , g ₁ , s ₁ , f ₁ k ₁ and sγ = 0.2 ... 0.5, we have the following relations for determining the parameters b ₁ , e ₁ , h _{1 of the} matrix vortex component of MPO F:

It should be noted that if it is difficult to ensure the angular velocity of the turn during the turns of the aircraft

, then you need to use the averaged values:

and use them in the previously obtained ratios instead of the current values of the angular velocities.

где знак ' обозначает операцию дифференцирования по времени.We write relation (1) in the following form:

where the sign 'denotes the operation of differentiation in time.

где Т_г, Т_в горизонтальная и вертикальная составляющие вектора

напряженности геомагнитного поля; вектор Н представляет собой вектор

, отнесенный к связанным осям ЛА.Denote:

where T _g , T _{in the} horizontal and vertical components of the vector

geomagnetic field strength; vector H is a vector

assigned to the associated axes of the aircraft.

В результате численного интегрирования одним из методов [4] уравнения (16) определяется величина вектора

и егокомпоненты Н_x, H_y, H_z в осях связанной с объектом системы координат OXYZ. Далее из уравнения (1), опустив ряд промежуточных преобразований, запишем окончательные соотношения для определения горизонтальной и вертикальной составляющих вектора напряженности геомагнитного поля [3]

Пример осуществления способа.Then:

As a result of numerical integration, one of the methods [4] of equation (16) determines the magnitude of the vector

and its components H _x , H _y , H _z in the axes of the OXYZ coordinate system associated with the object. Further, from equation (1), omitting a number of intermediate transformations, we write down the final relations for determining the horizontal and vertical components of the geomagnetic field intensity vector [3]

An example implementation of the method.

 The proposed method can be implemented using the device described previously, as follows.

при этом в точках ψ=0^° и при ψ=90^° в первый вычислитель 6 поступает с блока магнитометров 1 ДА две тройки значений составляющих вектора напряженности результирующего МПО и запоминается в нем, а также угла курса ψ с блока 2 и угловой скорости разворота

с блока 4. Затем ЛА вновь горизонтируется на поворотной установке и в точке при ψ=0^° ЛА разворачивают по углу крена γ на величину g=0,2...0,8 рад 0,2.0,8 рад с постоянной угловой скоростью

0,05.0,1 +/с и при, например,

0,2 рад в первый вычислитель 6 поступает с блока магнитометров 1 ЛА две тройки значений составляющих вектора напряженности результирующего МПО и запоминается в нем, а также угол курса ψ с блока 2, угол крена g с блока 3 и угловой скорости разворота по крену

с блока 5. На основании поступивших значений указанных величин первый вычислитель 6 определяет коэффициенты матрицы вихревойсоставляющей МПО (а₁, b₁, c₁, k₁) по соотношениям (5, 6, 9, 10, 13), которые запоминаются в нем; первый вычислитель 6 и блоки 4 и 5 задействованы только в процессе предстартовой подготовки. Во время движения ЛА по поступающим сигналам с датчиков на входы интегратора 7 с выходов первого вычислителя 6, блока магнитометров 1, гироскопа направления 2 и гировертикали 3 определяются в блоке 7 проекции вектора напряженности геомагнитного поля на оси связанной с объектом системы координат по соотношению (16), поступающие на входы второго вычислителя 8 одновременно с сигналами с блока магнитометров 1 ЛА и гировертикали 3.In the process of prelaunch preparation, the aircraft is installed on a deviation site on a non-magnetic rotary installation and is leveled. The aircraft is provided with directional circulation, at the points ψ = 0 ^° and at ψ = 90 ^{°, the} aircraft are fixed, and the first calculator 6 receives from the block of magnetometers 1 of the aircraft two triple values of the components of the stress vector of the resulting MPO and is stored in it, as well as the course angle ψ with block 2. Then at a point at ψ = 0 ^° , the aircraft is deployed along the angle of heel γ by the value g = 0.2 ... 0.8 rad or 10 ^o .45 ^o and, for example, γ = 0.2 rad The aircraft are fixed in a fixed position and the first transmitter 6 receives from the block of magnetometers 1 of the aircraft three values of the components of the vector of tension of the resulting MPO and remembered in it. Next, the aircraft is again horizontal on a rotary installation and performs directional circulation with a constant angular velocity

at the points ψ = 0 ^° and at ψ = 90 ^° , the first calculator 6 receives from the block of magnetometers 1 YES two triples of values of the components of the stress vector of the resulting MPO and is stored in it, as well as the heading angle ψ from block 2 and the angular speed of rotation

from block 4. Then the aircraft is again horizontal on a rotary installation and at a point at ψ = 0 ^{° the} aircraft is deployed along the roll angle γ by the value g = 0.2 ... 0.8 rad 0.2.0.8 rad with a constant angular velocity

0.05.0.1 + / s and, for example,

0.2 rad to the first calculator 6 receives from the block of magnetometers 1 LA two triples of the values of the components of the vector of tension of the resulting MPO and is stored in it, as well as the angle ψ from block 2, the angle of heel g from block 3 and the angular speed of roll

from block 5. Based on the received values of the indicated quantities, the first calculator 6 determines the coefficients of the matrix of the vortex component of the MPO (a ₁ , b ₁ , c ₁ , k ₁ ) from the ratios (5, 6, 9, 10, 13), which are stored in it; the first calculator 6 and blocks 4 and 5 are involved only in the prelaunch process. When the aircraft moves along the incoming signals from the sensors to the inputs of the integrator 7 from the outputs of the first calculator 6, magnetometer unit 1, direction gyro 2 and gyro vertical 3, they are determined in block 7 of the projection of the geomagnetic field intensity vector on the axis of the coordinate system associated with the object by the relation (16) arriving at the inputs of the second transmitter 8 simultaneously with the signals from the magnetometer block 1 aircraft and gyrovertical 3.

In the second calculator 8, the signals of horizontal T _g and vertical T _{in the} components of the geomagnetic field are generated by the ratios (17, 18) _, and by changing their amplitude they conclude that there may be magnetic masses at the place of passage of the mobile search apparatus.

As sensors of block 1, for example, flux-gage sensors can be used, as block 2 and block 3 can be used, for example, gyro-unit GA-8 and gyro-vertical MGV-2, respectively. The first calculator 6, the second calculator 8, the integrator 7, the first 4 and second 5 differentiating devices can be implemented, for example, on standard elements of computer technology [6]
The advantage of the proposed method of magnetometric reconnaissance from a mobile search apparatus, which includes determining the horizontal and vertical components of the vector of the geomagnetic field strength, is to increase the accuracy of the magnetometric exploration, since ignoring the vortex component of the MPO leads to errors in determining the geomagnetic field to 100.120 nT, which is extremely undesirable , since it very distorts and “noises” weak signals, as a rule, about magnetic masses at the point of flight of an aircraft .

The proposed dependencies for determining the horizontal and vertical components of the vector of the geomagnetic field intensity during the movement of the aircraft can be implemented by computation in the on-board computer [6]
The application was prepared with the support of the Russian Federal Property Fund.

Claims (1)

A method of magnetothermal reconnaissance from a mobile search engine, including, in the process of moving the search engine along a given route, measuring the horizontal and vertical components of the geomagnetic field, characterized in that they carry out preliminary preparation, during which the measuring axes of the three-component magnetometer are fixed relative to the building axes of the search apparatus, and a horizontal search the device sequentially in two course positions at a course angle of 0 and 50 ^o , and then at At a course of 0 ^o , the search apparatus is set to one arbitrary position along the angle of heel by 10 45 ^o , then the search apparatus is again horizontal and turned at a constant angular speed at a course of 0 90 ^o , and then at a 0 ^° course angle, the search apparatus is deployed with a constant angular velocity of the roll from 0 to 45 ^o, wherein in one and the same in each of these spatial positions search device measured projection resulting magnetic field of construction machine axis, and the course angle, pitch and roll, and in turn x the search apparatus also the angular velocity of the turn at the corners of the heading and roll, according to the obtained measurement results, find the vortex component of the intrinsic magnetic field of the search apparatus, and during the movement of the search apparatus along a given route, the horizontal and vertical components of the geomagnetic field are determined taking into account the magnitude of the vortex component of the intrinsic magnetic field search engine.