DE10315447A1 - Noise field compensating method for compensating magnetic noise fields associated with objects like ships relies on an object field measured by sensors to control the effect of noise fields - Google Patents

Abstract

Partially detected magnetic flux density readings on an object's/ship's (1) surface are used to determine actual magnetic flux density measurement value on a point in the space around the object by means of a functional unit containing a special algorithm, so that this value is suitable for controlling power elements that feed in a current in compensating coils. An independent claim is also included for a device for carrying out the method of the present invention with a functional computer and signal input devices linked to surveying probes (3) attached to an object's/ship's surface.

Description

The The invention relates to a method and a device which it allows the disturbing influence of a magnetic object, in the main of a ship, for certain selectable Minimize places in the object environment.

It It is known that the iron masses of a ship are different magnetic Effects are exposed and those in the marine environment cause. While The construction phase of a ship creates a permanent magnetic field in it the action of the constant effective earth field. Although this object field can by demagnetization treatments be reduced; because the earth field but also during ship operation continues to act on the object forms the permanent field always new.

Next the mentioned permanent field is determined by the position and course of the ship in the outer Earth's field caused a so-called induced field.

By electric current in conductors for power supply to consumers or in electrical producers and consumers, etc. form electromagnetic Stray fields.

When fourth magnetic component is the eddy current field to call that by changing the of metallic materials flow during unavoidable ship movements in the outer field is caused.

The different magnetic influences that the ship for the above reasons in its environment are mainly used in mine engineering used, the mine detonation in the appropriate moment of passing or by pass of a watercraft.

A the same danger generally applies in a similar way to land vehicles.

A state-of-the-art magnetic self-protection system (MES) is known from US Pat DE 39 36 985 , As essential in this device, the measurement of the real object interference field by means of a number of magnetic field probes directly at the location of the Feldlinienein- or exit from the object.

in the Contrary to conventional, realized plants can all changes the magnetic conditions currently understood and about a control system be compensated immediately.

The Output signals of the individual probes are a special Computer unit fed to the magnetic flux density at any Places outside of the object. These calculated values are used to these specific locations by means of an on-board control loop with magnetic field-generating actuators (coils) to the total interference field minimize or to some other arbitrary value.

When Disadvantage of this prior art device has been found that the previously used algorithm requires an object shell, the main ones from flat and perpendicular to each other arranged surface elements and because of these and other limitations only one calculation accuracy for the determination of the total interference field admitted the manipulation of miners to the present state the technology was fair. Future developments the ignition technology require improved component accuracy.

Of the The invention therefore has as its object the field distribution on the known or assumed mine location to calculate accordingly and as a controlled variable for the determination of the total interference field to use.

This is inventively those in the characterizing part of patent claims 1 and 2, and in the associated dependent claims specified characteristics solved.

Of the in the process according to the invention newly applied algorithm is based on a further theoretical basis and therefore allows for consideration arbitrarily shaped object covers. He leads additionally to a higher accuracy in the calculation of the magnetic field strengths to those considered relevant Places, which in turn serve as input parameters for the control algorithm. Overall, thanks to the new algorithm in conjunction with the Control algorithm the desired Field intensity distribution be realized with smaller deviations. Further increases Accuracy is possible through the densification of the sensor network. On This way may also apply to advancements in the field of fuze technology be reacted.

The invention is described below in the 1 such as 2 illustrated and explained in more detail in one embodiment.

It demonstrate:

the 1 - A schematic representation of a ship, which is provided with a number of field probes on its surface

the 2 - The device of the invention in a block diagram.

The 1 shows an object 1 here a hull, which on its surface a number of field probes 3 carries on it a field probe arrangement 2 form.

their Density and position with respect to the object surface will be the main thing determined by the compensation quality requirement for the Object as well as the topography of the object surface.

In the 2 the compensation device according to the invention of object-own magnetic interference fields is illustrated by a block diagram.

outgoing from the fact that for the defined compensation of an object disturbance field in a certain place, the optimal location for one Sensor would be exactly this place namely in the example used of a ship, which depends on a magnetic field-dependent ignited mine is endangered the liege of the mine, results in a measurement level in a certain Water depth.

There this is not feasible in the practical operation of a moving ship is, in the inventive solution this Measuring level directly as a shell placed on the object and from the measured values field values in the desired Water depth calculated.

The field probes located on the outer skin of the ship ( 3 ) are aligned so that they measure the component of the ship's field perpendicular to the outer skin.

These Measured values are sent to an electronic computer Function unit given.

The functional unit ( 5 ) According to the invention contains a mathematical model that in the form of a program sequence or as a hardwired circuit, the magnetic flux density B in the direction of the unit vector e at certain locations p (x, y, z) calculated and minimized according to the following algorithm.

In a first step, a magnetic potential distribution ψ → is determined as a solution of a linear system of equations so that the flux densities BB → _mess measured in the direction of the surface normal vectors n → are determined at the probe locations s (x, y, z).

BB → mess = μ · Ā · ψ → With
ψ →: n-tuple of the magnetic potentials ψ ₁ ... ψ _n
Ā: n · n matrix describing the location of the probe type to each other
BB → _mess : n tuple of the measured magnetic flux densities B ₁ ... B _n at the probe locations
μ: permeability

The individual components a _{ij of} the matrix Ā are given by the well-known potential theory

In the second step, the magnetic field distribution BB → _calculated at arbitrarily determinable locations p (x, y, z) (eg on a measuring carpet at a defined depth) is calculated on the basis of the calculated potential distribution ψ →: BB → calculated = μ · C - · ψ → With
ψ →: n-tuple of the calculated magnetic potentials
C -: n · m matrix describing the location of the probe type to the computing locations
BB → _calculates : m-tuple of calculated magnetic flux densities at specific locations
μ: permeability

The individual components c _{ij of} the matrix C - arise too

Overall, the magnetic field results distribution to BB → calculated = C - · Ā -1 · BB → mess ,

In a control algorithm, the flux density values BB → _calculated in the manner described are used as the input variable. The control algorithm calculates, for. B. by the method of least square deviation, currents for feeding into the compensation windings, so that the magnetic field at the predetermined locations is minimized or can be set to an arbitrarily determinable value.

Of the Algorithm can be in a the computer functional unit controlling Program be included or the claim 3 as hardwired be executed electronic circuit.

The functional unit ( 5 ) thus provides at its output the current flux density values for a z. B. automatically predetermined computing location, which corresponds to the depth measurement signal of a depth gauge - for controlling power elements ( 6 . 7 . 8th ), which are dependent on this signal in compensation windings ( 9 . 10 . 11 ) feed in such a current that the magnetic field resulting from the ship's disturbance field and earth's field exactly corresponds to the desired value at the computing location.

Instead of the depth meter dependent calculation point specification This can also be done automatically according to other criteria or after one manual specification.

1

Hull (Object)

2

Field probe arrangement

3

Field probe

4

magnetometer

5

functional unit for the Flux density calculation in the space point

6

Amplifier / power member for the Bz-compensation coils

7

Amplifier / power member for the By-compensation coils

8th

Amplifier / power member for the Bx compensation coils

9

compensation windings for high-axis compensation

10

compensation windings for transverse axis compensation

11

compensation windings for longitudinal axis compensation

12

output monitor

13

input keyboard

14

printer

Claims (7)

Method for compensating object-specific magnetic interference fields, in particular of ships, whose effect can be regulated as a function of the object field measured by sensors, wherein a current, which is determined by the actual effective object-specific magnetic interference field at certain locations outside the object, is fed by means of power elements in compensation windings, which is detected by a number of either directly on or near the outer skin of the object mounted field probes, each measuring the magnetic flux density perpendicular to the object surface, and these values are fed to a represented by an electronic computer functional unit controlled by a data processing program, the conversion of from the individual probes measured magnetic flux densities in magnetic flux density values in a predetermined direction at arbitrarily determinable locations outside the object makes and calculate them so In this way, values are then controlled as variables in a control algorithm to generate magnetic field-generating actuators such that the flux density at the specific locations outside the object is minimized or set to any other value, characterized in that the data processing program for controlling the functional unit represented by an electronic computer is the magnetic Flux density B in the direction of the unit vector e → calculated at certain locations p (x, y, z) according to the following algorithm, wherein in a first step, a magnetic potential distribution ψ → is determined as a solution of a linear system of equations so that at the probe locations s (x, y, z) set the flux densities B → _mess measured in the direction of the surface normal vectors n →; B → mess = μ · Ā · ψ → with ψ →: n-tuple of the magnetic potentials ψ ₁ ... ψ _n ¿: n · n-matrix describing the position of the probe in relation to each other B → _mess : n-tuple of the measured magnetic flux densities B ₁ ... B _n at the probe locations μ: permeability; - The individual components a _{ij of} the matrix Ā result according to the relevant known potential theory:

in a second step, the magnetic field distribution B → _calculated at arbitrarily determinable locations p (x, y, z) (eg on a measuring carpet at a defined depth) is calculated on the basis of the calculated potential distribution ψ →: BB → calculated = μ · C - · ψ → with ψ →: n-tuple of the calculated magnetic potentials C -: n · m-matrix, which describes the position of the probe to the computing locations BB → _calculates m-tuples of the calculated magnetic flux densities at the given locations μ: permeability; - The individual components c _{ij of} the matrix C - arise to

bringing the magnetic field distribution to BB → calculated = C - · Ā -1 · B → mess and the flux density values BB → _calculated as the input variable are used in a control algorithm, for example according to the method of least square deviation, to determine current intensities for feeding into the compensation windings so that the magnetic field is minimized at predetermined locations or at one can be set arbitrarily determinable value. Device for carrying out the method according to Claim 1 with a functional unit represented by an electronic computer ( 5 ), their signal inputs with a number of perpendicular to the object surface mounted field probes ( 3 ) are electrically connected, controlled by a data processing program, the conversion of the individual field probes ( 3 ) measured magnetic flux densities in at least one flux density value representing the magnetic flux density at any location in the object environment, and this value is electrically connected to a power element ( 6 . 7 . 8th ), which depends on this in compensation windings ( 9 . 10 . 11 ) feeds in such a current that the magnetic field generated by the object in its surroundings is minimized at selectable locations or is returned to an arbitrary value, characterized by a data processing program having the inventive features of the method according to claim 1. Device according to Claim 2, characterized in that the functional unit represented by an electronic computer ( 5 ) according to the inventive method according to claim 1 controlling program part, is replaced by a circuit constructed by means of electronic components. Apparatus according to claim 2 and 3, characterized in that the signal output of an existing on ships depth gauge with a corresponding input to the functional unit ( 5 ) is connected for the flux density calculation in the space point and the transmitted depth measurement is used to automatically follow a selected magnetic compensation of the respective water depth or an equidistant thereto. Apparatus according to claim 2 to 4, characterized in that the field probes ( 3 ) on the object wall ( 1 ) are mounted vertically inside or outside. Use of the device according to one of claims 2 to 5, for magnetic self-measurement. Use of the method according to claim 1, for magnetic Even surveying.