EP0745828B1 - Method for determining roll of a spinning flying object - Google Patents

Abstract

The roll position evaluation system uses a field strength vector (8) of the earth's magnetic field as a directional reference for determining the roll position of the flying object (1). The speed of the object is determined using e.g. NAVSTAR-GPS system. Pref. at least one magnetic field sensor (2) is used for providing the field strength vector of the earth's magnetic field at a given point on the flying object, used as a reference point for the roll position evaluation.

Description

The invention relates to a method for determining the Roll position of a rolling flying object, in particular for Guiding a ballistic flying projectile / missile with roll compensation.

But also with ballistic flying projectiles / rockets for other flying objects, the roll position is determined by vitally important, provided that a subsequent steering of these flying objects should take place during the mission. In particular, this applies to the steering of ballistic flying projectiles / missiles, where the possibility a trajectory correction is provided, such as is described in P 44 01 315.9.

In the present case, it is mainly about Flying objects, their rotation around the roll axis especially is pronounced. The rotating movements around the others Body axes (pitch and yaw movement) are compared low. It is assumed that at least one Direction reference, such as the direction of the speed vector of the flying object e.g. is known by measurement. Flying objects also become more stable, i.e., slow variable roll frequency considered, because only for this Movement type with the procedure presented here reliable determination of the roll position not only for individual ones Times is possible.

Up to now, roll positions have been determined by means of other inertial reference systems. This Devices and systems are mechanical / optronic Precision devices and therefore correspondingly expensive.

An above The method is known from DE 31 31 394 A1. For Determination of the rotational and roll position of missiles uses the geomagnetic field. The missile becomes a Earth's magnetic field sensor for displaying the normal orientation to Soil and an amplifier for the ongoing calculation of the Roll position under the influence of changing azimuth and Assigned elevation angle. To determine the Roll frequency is the amplitude of an induced AC voltage evaluated. However, there is no Metrological representation of the solution for the evaluation the required spatial position of the body axis and Earth magnetic field vector to the horizon. Accordingly, one Assignment of the roll phase "0" relative to the earth's magnetic field an additional device on the starting device is required.

The present invention is based on the object To develop methods of the type mentioned above which is a relatively precise determination of the roll position of the Flying object takes place and which only a little effort assumes.

• eine Feldstärke des Erdmagnetfeldes insbesondere ein Feldstärkevektor zur Bestimmung der Rolllage des Flugobjektes verwendet wird und
• ein Geschwindigkeitsvektor des/r Projektils/Rakete gemessen oder als Funktion oder in Form einer Tabelle im Auswerterechner gespeichert, zeitrichtig berechnet und als Referenz für die Rollagebestimmung verwendet wird.

To solve this problem leads that

• a field strength of the earth's magnetic field, in particular a field strength vector, is used to determine the roll position of the flying object and
• a speed vector of the projectile / rocket is measured or saved as a function or in the form of a table in the evaluation computer, calculated in good time and used as a reference for determining the roll position.

This procedure is intended to control a ballistic flying projectile / rocket with roll compensation used become. A field strength vector of the earth's magnetic field is called Direction reference used.

A magnetic field sensor measures the component of the Geomagnetic field preferably in the radial direction to / r Projectile / missile. Depending on the Roll position an alternating, sinusoidal course of a measured intensity, whose minima and maxima indicate that the measuring direction on the course of the earth's magnetic field on next one is. From the time interval of the maxima / minima the roll frequency is determined.

The location of the magnetic field sensor is also the reference point for the rolling position.

The roll axis of the obedient flying object is determined by the Approximate speed vector. The direction of the Velocity vector is known because it is either called Target course determined during mission planning and stored in an evaluation computer or during the Flight e.g. is measured with NAVSTAR-GPS.

The orientation of the field strength vector is in advance known reference system and in one Evaluation computer saved.

From the orientation of the direction reference (e.g. speed vector) and field strength vector, the roll position of the projectile / rocket for the times of the maximum or calculate the minimum intensity. Between these The rollage is determined with the determined times Roll frequency predetermined. By considering the System dead time, i.e. the time required for the evaluation Time, the accuracy of the roll position determination is additional increased.

It is of course also within the scope of the invention that multiple magnetic field sensors are used, making one more precise determination of the roll position is possible.

The case that the trajectory of the projectile / missile is open a field line of the earth's magnetic field, can especially with ballistic flying missiles as singular exceptional case can be seen. In this An exception is a determination of the roll position with this Procedure not possible because none despite rolling motion Field strength changes across the trajectory occur. This Exceptional cases can be achieved through appropriate mission planning be avoided. If he does enter, he will be removed from the Process recognized automatically.

Figur 1 eine schematische Darstellung der Beziehung zwischen einem Flugkörper und dem Erdmagnetfeld;

Figur 2 eine diagrammartige Darstellung des erfindungsgemäßen Verfahrens zum Bestimmen der Rollage eines Flugobjektes.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

Figure 1 is a schematic representation of the relationship between a missile and the earth's magnetic field;

Figure 2 is a diagrammatic representation of the inventive method for determining the roll position of a flying object.

According to Figure 1 is a flying object 1 with a Magnetic field sensor 2 and a measuring axis 3 shown. This Flying object has a speed vector 4 and one Roll axis 5. The arrow w represents the roll angle of the Flying object 1 with respect to a vertical reference axis (VRA) 6. A field line 7 of the Earth's magnetic field drawn with a field strength vector 8.

The field strength vector 8 is used to determine the Roll position of the flying object 1, the Speed vector 4 of the flying object is known.

The method of operation of the present method is the following:

As a result of the rolling movement of the flying object 1, the Magnetic field sensor 2 with respect to its measuring axis 3 alternating, sinusoidal course of the intensity of the Magnetic field. This curve is a function in FIG. 2 shown over time t.

Only the qualitative is decisive for the evaluation Course of a measurement signal 9 with its pronounced maxima and minima, as well as those belonging to this maxima / minima Points in time 10.

A time interval Tp between two maxima or two minima is the duration for one revolution of the roll Projectile / missile. The roll frequency is determined from this.

The speed of the flying object 1 becomes independent of determined the full procedure. this happens for example via NAVSTAR-GPS (Global Positioning System), with the help of which position values of the / r Projectile / rocket and also speed determined become.

In addition to the position and speed of the flying object 1 also the direction of the VRA 6 in a previously defined Reference system known. The process uses the Velocity vector 4 as an approximation for the roll axis 5 of the flying object 1.

Roll axis 5, VRA 6 and field strength vector 8 let the Determination of the roll position of a reference point, e.g. location of the Magnetic field sensor 2 at the time when the measuring axis 3 matches field line 7 as much as possible. Between The roll angle w is calculated in advance of these times from the roll frequency and the time span after the last one Reference measurement.

Claims (6)

1. Method of determining the roll position of a rolling flying object, more especially of steering a ballistically flying projectile/rocket having compensating roll movement, wherein

   a field strength of the earth's magnetic field, more especially a field strength vector (8) is used for determining the roll position of the flying object (1), and

   a velocity vector (4) of the projectile/rocket is measured and used as the reference for determining the roll position or is stored as a function of, or in the form of, a table in the evaluation computer, calculated in a correctly timed manner and used as the reference for determining the roll position.
2. Method according to claim 1, characterised in that the field strength vector (8) is used as the direction reference.
3. Method according to claim 1 or 2, characterised in that at least one magnetic field sensor (2) of the flying object (1) detects, at at least one specific location on the flying object (1), the field strength of the earth's magnetic field and, hence, the field strength vector (8).
4. Method according to claim 3, characterised in that the locat~on of the magnetic field sensor (2) is used as the reference point for detecting the roll position.
5. Method according to claim 3 or 4, characterised in that, caused by the rotation of the flying object (1) about its axis of roll (5), alternating intensities of a measurement signal (9) are detected as minima and maxima over the time (t), and hence over an angle of roll, by the magnetic field sensor (2) in dependence on its roll position.
6. Method according to one of claims 3 to 5, characterised in that the field strength, and hence the field strength vector (8), is detected by the magnetic field sensor (2) radially relative to the axis of roll (5) of the flying object (1).

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