DE2436641A1 - METHOD, SYSTEM AND DEVICE FOR TRACKING AND DETERMINING AN OBJECT - Google Patents

Description

4S99 Hem «, 8000 WDnthan 40,

Frrlily.Othstrti ^ 19 r »f ~ l I ·.» Bra »J« »·» »Eiranacher SiraBe 17

»· *«. * «O Dipl.-Ing. RM 3a »ir _Fjl . _{Anw B6liIar}

P «t.-Anw. Horrmann-Trontepohl Dfßl.-PhVS. Eduard ΒθΙζΙθΓ Telephone: M3O11

Telephone: 51013 * S5 3012

^{5101 <} Dipl.-Ing. W. Herrmann-Trentepoh! 333013

TeleoinmmPncJirm: Telegremmanschrltt:

DnhrpaionW Harne "A IUNI ANWAL I C Babetzpat Munich

Telex OB 229 853 __. Telex 5 215

1 bank accounts:

I Bavarian Verelnsbenk Munich 952 Ä37

Dresdner Bank AG Herno 7-520 4 & Q PostschocStkonto Doitmund 558 es-4b7

Rot .: HO 4826 Dr.Kl / hr

In the answer please r ngebon

Please send a letter to:

Munich pick-up event 3

Polhemus Navigation Sciences, Inc.

P.0 _e box 1101

Burlington, Vermont (USA)

Method, system and device for tracking and determining the position of an object

The invention relates to a system or method for determining the position or tracking of an object, with a vector field that is a nutation around an axis that the Direction vector is called, executes, is used to track down the spatially distant object or positionally to determine. The invention also relates to a device for generating such a nutation field, in particular a magnetic nutation field, which

509809/1033 - ² -

executes a nutation around an axis, the direction vector is called. In particular, the invention relates to a system or method with which both the relative Translation, as well as the relative angular orientation, the coordinate system of the distant object relative to the Reference coordinate system of the device that the Nufcaticnsfeld generated and aligned, can be determined.

The use of orthogonal or right-angled coils for generation and scanning magnetic fields are known. Such devices were mainly used in the field of measuring magnetic fields used, for example, to gain a better understanding of their properties. When a magnetic field ura a generator coil can be measured very precisely by using scanning coils, it is obvious conversely, that it must be possible to determine the position of scanning coils relative to the generating coils on the basis of the scanning signal to be determined. The problem that arises is, however, that there is more than one location and / or orientation within a common magnetic dipole field, which have the same characteristic scanning signals in a sensing coil. In order to use a magnetic field for this purpose, additional information is required be created.

One attempt to obtain additional information for this purpose is to contrast the generators and sensing coils with one another as described in U.S. Patent 3,644,825. The movement of the coils creates changes in that magnetic field and the resulting signals can be used to determine the direction of movement or determine the relative position of the generator and sensing coils.

509809/1033

Though this solution does some of the ambiguity of orientation on the basis of the scanned field, the accuracy of the determination depends on the relative Be movement and cannot be used at all without relative movement.

Another attempt that has been proposed to obtain the additional information needed involves the rotation of the magnetic field _r as described by Kalmus in "A New Guiding and Tracking System", IRE Transactions on Aerospace and Navigational Electronics, March 1962, pp 7-10. In order to determine the distance between the generating and scanning coils precisely, this solution requires that the relative position of the coils to one another remains the same. The system therefore cannot be used to determine both the relative translation and the relative orientation of the generator and sensing coils.

Although the related art for determining and tracking distant objects is sophisticated, there is still a need for a way to determine the relative angular orientation of a distant object in addition to locating or tracking the object. There remains a need for an apparatus, system, or method that operates on signals sensed by a probe, the signals originating from a nutation field generated by a single device and capable of adjacent one permanent position determination or tracking of the distant object and scanner, in addition and at the same time a continuous determination of the relative angular

809809/1033

Orientation of the distant object and scanner.

It is. accordingly an object of the invention, a system and method to create that both the relative translation or. Displacement, as well as the relative orientation of the distant Object can be determined by using a vector field.

Another object of the invention is relative translation and orientation of distant objects by using a field in a continuous manner, so that the translation or shift and orientation can be followed and can therefore be continuously determined.

It is another object of the invention to provide a system and method for the precise determination of the position of an object relative to a reference coordinate system of means for generating a To create vector field.

It is a further object of the invention to provide a system which comprises a directional vector which is modulated by a Field is used to track an object very closely.

It is another object of the invention to provide a generator or transmitter capable of electronic generation of a field nutating about a particular direction vector in the above system and method Is used.

It is therefore a further object of the invention to provide an effective signal transmission technique with which the

- 5 -509809/1033

Measurement of the relative displacement or translation of a distant object (two angles) in addition to pointing at the same time Measurement of the relative angular orientation of the distant object (three angles) is possible. With the In accordance with the invention, means are therefore provided for making five independent angle measurements using only one device Field generation and only one device for field scanning on the distant moving object to perform.

The above and related tasks can be accomplished through the use of the system, method and the field generating device, which will be described below. The invention is based on the consideration that the only places in a dipole nutation field at which the field strength remains invariable in size, lie along the axis of nutation, which the direction vector is called here. This phenomenon allows a very precise location or tracking of a distant object that not only changes its place but also its angular orientation.

The system according to the invention has means for generating a directed nutation field, such as a magnetic field that rotates around a direction vector. Means are also provided on the remote object which is to be tracked or determined in terms of its position, in order to scan the field.

If the system is only to be used to determine the position of the object, eg for small disturbances in the directional angle, means are provided for generating a signal which is based on the scanned field and which indicates the position of the object. When the system is used to track the object, signal generating means are placed between the

5 0 9809/1033

Sampling means and the field generating means switched on, which emit a signal to the field generating means, the is based on the scanned field in order to direct or track the direction vector of the nutation field on the scanning means. Preferably, orthogonally directed coils are used both for generating the nutation field, which in this case an electromagnetic field, as well as being used to sample the resulting field.

Embodiments of the invention are shown below with reference to FIG accompanying schematic drawing, for example. Show it

1 shows the geometry of a simple coordinate transformation called a rotation;

Figure 2 is a block diagram of a single rotation operator after Fig. 1, called the resolver;

3 shows a circuit which gives a two-dimensional magnetic nutation field in the plane a degree of freedom of rotation of 360 ° there;

FIG. Aa the direction angles which are defined for a three-dimensional alignment; FIG.

Fig. Ab dea circuit which corresponds to the alignment angles of Fig. Aa;

Fig. 5 is a schematic representation of a known system for generating and scanning a magnetic field;

Fig. 6 is a representation of the signals generated in the system according to

509809/1033

Fig. 5 are scanned;

7 shows the schematic representation of a system for implementation of the invention, for determining the position and orientation of an object that is in a zvreidimensionalen Space moves;

Fig. 8 shows the representation of the signals which are sampled in the system of Fig. 7;

9 illustration of a simplified two-dimensional Systems using a two-coil generator and a two-coil scanner;

Fig. 10 is a schematic representation of a system according to the invention, with which the position and the angular Orientation of an object can be determined that moves freely in two-dimensional space; and

11 shows the schematic representation of a system according to the invention, with which the position or direction and the relative angular orientation of an object can be determined, which is in three-dimensional Can move space with certain restrictions.

The device according to the invention for generating a directed, magnetic nutation field along a direction vector has at least two at right angles to each other stored coils through which the excitation currents are sent. This excitation current normally exhibits

- 8 509809/1033

a specific carrier frequency associated with a DC signal and / or an alternating current signal is modulated. These modulation envelopes are only used below referred to as a DC or AC speed signal. The AC signal has the nutation frequency. The circuit for supplying a direct current through one of the coils and an alternating current through at least one additional orthogonal directed further coil generates a magnetic nutation field whose direction vector is in the direction of The axis of the DC coil lies, or, more precisely, in the direction of the axis of the DC field. The amplitude the nutation depends on the relative amplitude of the AC and DC signals, which in most cases can be chosen with the same amplitude. If the object can only move in two dimensions, it needs nutation just a simple tipping back and forth on the plane of movement to be. This can be generated by a direct current signal in one of the coils and an alternating current signal in the second coil with the coils both in the plane of motion lie. If the object can move in three-dimensional space, the nutation desirably leads to a cone-shaped one Movement around the direction vector of the field, with the apex of the cone at the intersection of the coils. Such a nutation field can be created by the combination of a direct current signal in one of the coils, an alternating current signal in a second coil and another AC signal with a phase equal to the square of the phase of the first AC signal is generated in a third coil, with all three coils in their mutual spatial arrangement are aligned orthogonally.

Both in the two-dimensional described above, as well as the three-dimensional nutation field, the directional

509809/1033 " ⁹ "

vector rait the direction of the axis of the DC field together. In order to make this nutation field directable, signal processing means, as a coordinate transformation circuit are known to act on ßzugssignale for AC and DC excitation to the nutation field to give desired direction. Below is a brief Discuss the coordinate transformation known as rotation as a basis. given to the principles which the techniques of the invention are based, to make better understandable.

The transformation of a vector by rotating it from one coordinate system or frame to another coordinate system or frame is used as the resolution of the vector from the one into the new coordinate system designated. In this context, dissolving and dissolving are synonyms for transforming and transforming. Of the Operator that divides the components of a given vector in a coordinate system or frame into its components transformed into another coordinate system or frame, the two coordinate systems being replaced by a simple Angular rotation merge into one another is referred to here as a resolver. The equations for this Transformation are the following:

= x ^ cosA + y ^

sinA

In this case the z ^ -axis is the thing of rotation. the Equations can be easily understood from the geometry shown in FIG. 1. It must be noted that,

5 09809/1033 -1O-

if the two components affected by the resolver; are positive, the first component of the positive pair; always has the positive sine term when the angle of rotation is positive. If the angle of rotation is negative, the sign of the sinusoidal pressure is reversed. A suitable representation for a resolver is the block diagram shown in FIG. 2, in which case a negative rotation about the y-axis is shown. The y ~ component is therefore not affected by the transformation .. This fact is indicated in the diagram by the fact that the component passes directly through the block, whereas in a block would be the Figure 1, the Z _-.. Axis runs straight through the block. This representation should be viewed as a signal flow or block diagram for vector components, which is particularly useful for describing the calculation strategy that is used according to the invention.

The method according to the invention includes the generation of a directional nutation field that surrounds a nutation carries out an axis called a direction vector. Im two-dimensional In the case, a single resolver acts on the orthogonal AC and DC components of the train nutation vector of excitation to get the appropriate mix of AC and DC in each of the two generating coils so that the direction vector, together with the entire magnetic nutation field structure, is so directed is that an angle is formed with the reference x-axis as shown in FIG. The excitement for the zv / ei generator coils, which is necessary to bring the direction vector in the required direction, which is through the angle A is defined is determined by the following equations:

509809/1033

- ΛΑ - * U

Excitation for the X coil »(direct current) cosA -

(Alternating current) sinA

Excitation for the Y coil = (alternating current) cosA +

(Direct current) sin.A.

The arithmetic circuit, which is used for a precise alignment of the magnetic nutation field for the three-dimensional case, works essentially on the same principle as in the two-dimensional case. The B _e zugsnutationsvektor the excitation now consists of three components: a DC and two AC signals which are in square dependence. The direction vector and its entire nutation magnetic field build-up are brought into any desired direction, which can be defined by the angle sizes A and B. 4 shows the rectilinear geometry and the computing circuit for coordinate transformation; which is necessary to obtain the desired alignment by acting on the given three reference excitation signals. A more detailed explanation of the coordinate transformations, calculations and applications is given by Kuipers, J. "Solution and Simulation of Certain Kinematics and Dynamics Problems Using Resolvers", Proceedings of the Fifth Congress of the International Association for Analog Computation, Lausanne, Switzerland, 28.8. to 2.9.1967, pages 125 to 134, to which reference is expressly made here.

The method according to the invention includes the generation of a field which nutation around a direction vector executes. The generated field is in at least two axes on the to be tracked or to be determined in terms of position Object scanned. From the evaluated relationship between the field components scanned in each of the orthogonal axes

509809/1033 -12-

nents, the position of the object can be determined relative to the direction vector of the field and from this the position of the property. In order to track the object, the direction vector of the nutation field is moved until it is scanned in two axes Field, after suitable evaluation of the coordinate transformation, indicates that the object is aligned along the direction vector. This happened when that evaluated signal, which originates from the sampled nutation field, does not change in size during the nutation cycle changes. If a directional error exists, then the modulation amplitude sampled in the target direction is proportional to the angular deviation of the object from Direction vector. More precisely, the relative phase of the sampled and evaluated signals compared to the reference signals for field generation is proportional to the orientation, of the object relative to the direction vector. The modulation amplitude of the sampled and processed signal in The direction of the direction vector is proportional to the angle · deviation from the direction vector.

It can be seen from the above explanation that the direction vector can continuously track the object. This results in two angular measurements, which define the position of the object. The determination of the angular However, the orientation of the object is completely independent of this. The orientation of the object is generally given by three Euler's angle is defined (see also the Kuiper reference), which is relative to the reference coordinate system of the Generator or generator are measured. Two of the three angular orientation error measurements are proportional to any projections of the scanned and evaluated direct current field components, which are in coordinate directions of the Plane exist that is perpendicular to the pointing direction and

- 13 509809/1033

.η-

which are greater than zero in amount. The third error measurement for the angular orientation is proportional to the relative Phase of the sampled and evaluated nutation signals in this orthogonal surface compared with the reference excitation of the nutation of the generating or generator means.

This system, the device for generating a nutation field around a direction vector and the method make it possible to determine the position of a distant object very precisely and to follow, both in terms of its position and its angular orientation. Although the invention at a wide variety of situations in which the positional determination of distant objects or the tracking of coordinates, In addition to the orientation angles of the object required, the invention can be used according to a preferred embodiment for use in tracking the position and angular orientation of an observation head, in particular its line of sight, intended for visually coupled control systems. As part of this Limited application is the direction of view of the pilot constantly and precisely relative to the coordinates of the aircraft Are defined. Many other applications, such as automatic landing or rendezvous maneuvers, remote-controlled vehicles, self-controlled air-to-air refueling, formation control, etc. are all applications that go a long way work larger area. In general, any situation is where two or more independent bodies or coordinate systems occur and where it is desirable not only to measure the relative distance or position of the systems, to track them and precisely controlled, but where it is also desired, simultaneously and with the same device accurate measurement, tracking and control of the relative

- 14 -5 09 809/1033

./Mf.

Perform angular orientation of the two systems, a potential application for the invention.

In Fig. 5 are the elements of a known system for generating and magnetic field scanning are shown that cannot be used to position an object and to determine or track its orientation. The known system has a magnetic field generator 10 a coil 12, in which copper or another conductive wire on a magnetic, preferably isotropic Core 14 is wound. A current source 16 for the current i with any carrier frequency is connected to the coil 12 via the Lines 18 and 20 connected. The scanner 22 is one Coil 24, which is also preferably wound on a magnetic isotropic core 25, as in the case of the generator coil 12. Sampling circuitry 26 is connected to coil 24 via lines 28 and 30.

When using the known device, the current i conducted through the coil 12 generates a magnetic field 32. The coil 24 of the scanner 22 is moved to various locations around the generator coil 12 and those in the coil 24 induced currents represent a measure of the strength of the £; magnetic field 32 at the various points. The coil 24, the coordinate axes of which are 33, 35 and 37, can with respect to the reference coordinate axes 34, 36 and 38, in addition to a simple displacement of the coil in the directions X, Y and / or Z, different relative Assume angular positions by rotating around these axes x, y and / or ζ.

In Fig. 6 the output signal and coil 24 is shown, which is picked up by the scanning circuit 26 for a given field 32.

509809/1033 ~ ¹⁵ ~

nommeri is that of the flowing through the coil 12 Current i is generated when the coil 24 is rotated through 360 ° either about the y-axis 35 or the z-axis 37. the Coil 24 could, however, be moved in innumerable places around the coil 12, where the above Rotations of the spool 24 would in turn result in the same output signal, as shown in FIG. this demonstrates in a simple manner why the known device cannot be used in a unique way to define a relative position or a relative angular orientation of the sensing coils 24 with respect to the coil 12.

In FIGS. 7 and 8, coil 12 is shown, which gives field 32 a nutation in the sense of a simple tilting movement, which is generated by nutation means 44 which are connected to coil 12 via line 46 through a predetermined angle 48, e.g. 45 ° _{f are} connected. The resulting output curves as sampled by circuit 26 are shown in FIG. The shift or translation and rotary movements are limited to the XY plane. The curves in FIG. 8 show the method on which the invention is based. In Fig. 7, two mutually perpendicular angular orientations for the scanning coil 24 are shown. In either of these two orientations, an AC and a DC component are generally induced in coil 24. When coil 24 is aligned with the y-axis, which should be orthogonal to directional axis 50, the induced signal at the underlying nutation frequency consists of an alternating current component with the value zero and a direct current component also with the value zero. When the coil 24 is aligned with the x-axis which coincides with the directional axis 50, the induced signal consists of

- 16 509809/1033

of the total direct current component and, in turn, an alternating current component of the value zero "at the underlying Nutation frequency. The two important signals for determining relative orientation and translation or displacement are the direct current signal induced in coil 24, when this is in the y position and the AC signal in the x position. Both are zero as shown in the first two curves of FIG. 8, if there is no orientation or translation error exists.

If a translational shift or error exists, then the sensing coil 24 is a W _e chselstromsignal 47 scanning in the x-position with the underlying nutation frequency. The size of this signal is proportional to the size of the translation error; its phase either 0 ° or 180 ° indicates the direction of the fault.

If an orientation error exists, the scanning coil 24 scans a direct current signal 45 in the y position. The size and polarity of this direct current signal is a measure of the size and direction of the orientation error.

The device according to FIG. 7 enables the method according to the invention to be carried out for determining the position and orienting the coil 24 by alternately aligning the coil 24 along the x and y axes, wherein It is assumed that the degrees of freedom of movement of the coil 24 are such that these alternate with the x and y-axis coincides. When there is movement in the X, Y and Z directions, i.e. in all three Dimensions, then more than a simple planar nutation in the X, Y plane is required to allow the movement

- 17 509809 / Ί033

characterize, as will be described in greater detail below. It is in the X-Y «plane however, it is far easier to use two coils arranged orthogonally to one another, as in the device according to FIG. 9, than constantly changing the position of the coil. Coil 24 of Fig. 7 was therefore arranged orthogonally by the Replaces coils 52 and 54 each connected to sensing circuits 26 by lines 56 and 58 and 60 and 62, respectively. While the nutation of field 32 in Fig. 7 through angle 48 can be achieved by any suitable method, as for example by means 44 which impart a mechanical nutating motion to the coil 12 in FIG this is best generated electrically using a pair of coils 64 and 66, which are also orthogonal to one another are arranged. Current sources 68 and 70 are connected to each of these coils by leads 72 and 74 and 76 and respectively 78, as shown, current source 68 provides a DC signal i to coil 64 and current source 70 provides an AC signal, e.g., Msin Wt, to coil 66. These signals can be either simple DC and AC signals, or both may be superimposed on a suitable carrier frequency, such as 10 kilohertz be. In these cases the terms alternating current and direct current refer to the modulation envelope, the each curve is defined. In either case, the resulting magnetic field in the device of Figure 9 becomes nutation run about a directional axis 80 which always coincides with the axis of the coil 64 when the AC signal an alternating magnetic field is generated in coil 66, which is vectorially added to the magnetic field generated by the direct current signal is generated in coil 64.

- 18 -

509809/1033

In practice, an object on which orthogonally arranged scanning coils 52 and 54 are mounted is free to move in the plane defined by the axes of the coils. If the system is intended to track the object, the generator coils 64 and 66 should have the ability to generate a magnetic field that nutates about a direction vector 80 with an angular mutation amplitude 49 measured from vertex to vertex, where the direction vector 80 does not coincides with the axis of the coil 64. Such magnetic fields can be generated by feeding suitable mixtures of alternating current and direct current signals into the coils 64 and coils 66. As described earlier, the amplitude 49 of the nutation angle depends on the relative amplitude of the reference DC and AC sources 68 and 70, respectively. The angle that the direction vector 80 forms with the reference x-axis of the coil 64 is determined by the mixing process performed by the resolver circuit or the process suggested in the description accompanying FIG Lines 72, 74 and 76 and 78 are switched on between sources 68 and 70 and coils 64 and 66, respectively. The resolver operates with fixed Gleichstrora- and AC reference signals from the sources 68 and 70, sod _a ß the processed signals output from the resolver to the excitation of the generator coils 64 and 66, now have the capability of the direction vector 80 of the Nutationsfeldes to any desired angle A set up over a full 360 ° in accordance with the following equations:

Excitation of the coil 64 »(direct current) cosA - (alternating current)

sinA

Excitation of coil 66 = (AC JcosA + (DC st rom) sinA

- 19 509809/1033

To provide sufficient information for tracking or tracking the position and angular orientation of an object with scanning coils 52 and 54 attached thereto in one area, the scanning circuits 26 have the ability, after performing the coordinate rotation of the induced in the scanning coils 52 and 54 Signals the AC error component in the directional. vector and the DC error component in the direction to be determined orthogonal to the direction vector. The relative phase and magnitude of the AC fault mentioned above is proportional to the direction and size of the alignment error. the The polarity and magnitude of the DC error component mentioned above is proportional to the direction and magnitude of the Error in the calculated orientation angle of the distant object. These two error signals, which are proportional to the Angular errors in the directional angle and / or to the angular error in the relative orientation angle of the object - will be added used to make corrections in the previous measurement of these two angles. The change in straightening angle shifts the direction vector until the sensing coils 52 and 54 are aligned thereafter, in which case the AC error signal measured in the direction of direction vector 80 goes to zero. The marked change, required for the orientation angle improves or corrects the calculated orientation angle which the relative coordinate relationship between the coordinate system of the generator coils 64 and 66 and the coordinate system of sensing coils 52 and 54. If this relationship in the signal jumper is appropriate from the Orientation angle resolver - o- is displayed, then becomes also the DC error signal in the direction orthogonal to direction vector 80 will become zero. In summary and with reference to FIG. 10, a method according to the invention is

509809/1033 " ² °"

Richtiang sum continuous tracking or tracking of the relative position or direction and the relative angular orientation between two independent bodies in described on an area. The reference coordinates of the surface are defined by the X-axis 84 and the Y-axis 86, the coincide with the field-generating coils 64 and 66, respectively. Both the translation or displacement, and also the Orientation angles are measured in relation to this reference coordinate system. The sensing coils 52 and 54 are attached to a distant moving object and defining their mutually orthogonal axes 90 and 92 the coordinate system of the object that is tracked both in terms of its location and its orientation shall be. To create a nutation magnetic field, that in a certain direction relative to the fixed coordinate system of the generator coils 64 and 66 is directed, there is a certain mixture of direct current in each of the generator coils and AC excitation signals are required. The resolver 102 prepares the reference excitation signals for direct current and AC power received on lines 104 and 106 from power sources 68 and 70, respectively, according to one of assumed input straightening angle. A 82 so that appropriately mixed resolver output exciter signals are generated which via lines 108 and 110 to the generator coils 64 and 64 respectively. The direction vector 80 and its accompanying Nutation fields are therefore inclined at an angle A with respect to the reference or reference X-axis. The generated nutation field is nominally directed toward sense coils 52 and 54. The vertex-to-vertex amplitude of nutation 88 is is set and is usually 45 to 90 ° and depends on the relative size of the two signals set for the DC and AC excitation from sources 68 and 70. It is clear that those induced in the sensing coils 52 and 54

- 21 509809/1033

Signals not only depend on the direction angle A, but also on the relative orientation angle - ^ 94. For this reason, the signals induced in the coils 52 and 54 are connected by lines 112 ″ and 114 to the resolver 96 and are processed by the resolver 96, the Part of the alternating current and direct current mixture of the two signals is separated or separated, which comes from the orientation angle = 3> 94, if this is greater than zero. The two output signal components of the resolver 96 are connected by lines 116 and 118 to the resolver 98, the further segregates the DC and AC signal mixing, which is necessary to obtain the desired directional angle A 82. If the assumed directional angle A and the assumed orientation angle ^> are correct, the output components from the resolver 98 will be completely segregated nominal DC output signal 120 no AC modulation error, which indicates that there is no direction error. Likewise, no DC component is superimposed on the nominal AC signal 122, which indicates that the calculated orientation angle is correct. In the event that the angles * => . and / or A are incorrect, what the F will be _a ll when very small errors are expected, such as occurs when working under dynamically changing circumstances, the sampling circuits 26 receive the AC and DC error displays on the lines 120 and 122, These relate to the errors in the determination of the angles and and feed the corresponding differential changes on the lines 124 and 126 to the angle measuring circuit 100, which stores them in the corresponding angles. These improved angle measurements of ^> and A are used to

- 22 509809/1033

appropriate resolvers entered, in this embodiment in lines 132, 134 and 136 in a constant feedback arrangement. It follows that the corrections which are present at the outputs 128 and 130, the error measurements of the Reduce components 124 and 126. These principles can be applied to three-dimensional by applying the system shown in FIG Applications can be expanded.

As in the system of FIG. 10, the system of FIG. 11 has magnetic field generating, it coils 64 and 66 and magnetic field scanning Spools 52 and 54 on. A third one that produces Magnotfeid Coil 158, which is mutually orthogonal to the coils 64 and 66, and a third magnetic field scanning end Coil 248, which is mutually orthogonal to the coils 52 and 54, is used to measure the Information provided in the third dimension. For ease of understanding, the three coils are in each one Case shown spatially separated. Cut into reality however, the magnetic axes of both the generator coils and the scanner coils are mutually orthogonal Ratio as shown by the Cartesian coordinate axes 84, 86, 160 and 90, 92, 170, respectively. Farther an additional AC reference excitation signal is created so that AC 1 (AC1) and AC 2 in are in a quadratic relationship or are 90 ° out of phase. They can be used as sine waves with the same amplitude but 90 ° phase shift can be considered, although the two reference signals AC 1 and AC 2 are not necessarily must be sinusoidal in the practical embodiment of the system. Reference is again made to Figure 4, which illustrates the earlier discussion of the coordinate transformation circuit concerns and which shows the three-dimensional rectilinear geometry. As in the case of the

- 23 509809/1033

-W-

showed two-dimensional embodiment allows the Ability of directional vector 180 to point in any direction in which the arrangement of sensing coils 52, 54 and 248 can move, tracking the sensing coils. The reference excitation signals for direct current (DC), the alternating current 1 (AC1) and the alternating current 2 (AC2) from sources "68, 70 and 140 define a conical nutation magnetic field 164 about a straightening axis 180, which coincides with the axis of the direct current component of the field coincides. It should again be emphasized that the orientation of the change 180 is based on electrical way is done by a circuit to be described, while the generator coils 64, 66 and 158 in one fixed orientation to one another remain. DC power source 68 and AC power 2 source 140 are through Lines 142 and 144 connected to the resolver 220, the output line 148 of which together with the output line 146 of the Viechseistrom 1 source 70 are connected to the trigger 222. Output lines 154 and 156 carry the excitation signals from resolver 222 to generator coils 64 and 66. The generator coil 158 is excited via line 152 from the output of the dissolver 220 "The two angles. A and B the dissolver 222 and 220 therefore work on the reference vector input of the nutation field, the components of which are the reference excitations of the Sources 68, 70 and 140 are such that the direction vector 180 and its accompanying nutation field are in accordance with the 4 are aligned with the geometry shown in FIG. The direction vector 180 points in the direction of the scanner, which is on attached to the remote object to be tracked by the system. This scanner consists of three reciprocally orthogonally arranged scanning coils 52, 54 and 248, which are attached to the distant object and which, according to a preferred embodiment, with the main axes of the

- 24 509809/1033

distant object coincide, so that when determining the orientation of the scanner trinity, the orientation of the distant object is determined at the same time. As in the description of the two-dimensional case shown in FIG. 10, the signals induced in the scanning coils 52, 54 and 248 depend on the orientation of their scanning coordinate systems, which are mutually perpendicular coordinate axes 90, 92 and 170 are formed relative to the directional axis 180 and its two orthogonal nutation components of the jfU'ta'ti ⁰¹¹ "" field. In other words, the particular mix of the three reference excitation signals direct current (DC), alternating current 1 (AC1), and alternating current 2 (AC2) from sources 68, 70 and 140 induced in each of the three sensing coils 52, 54 and 248 hang not only on the two directional angles A and B, which determine the composite directional coordinate transformation circuit 252, but also on the three Euler angles, which define the relative angular orientation of the distant object and which determine the composite orientation coordinate transformation circuit 250. The H ^A uptfunktion the two coordinate transformation circuits 250 and 252 in the overall processing strategy of the system is that the transformation circuit 250 separates the part of the Bezugssigna3.mischung induced in the sense coils and the relative orientation of the remote object is allocated and the Roordinatentransformationsschaltkreis 252 the the remaining part of the reference signal mixture, which relates to the directional angle, is unmixed. If the three orientation angles that define the coordinate transformation circuit 250 and the two directional angles that define the coordinate transformation circuit 252 appropriately define the physical relationship between

- 25 509809/1033

don represent scanner and generator coordinate systems, then the signals sampled by sampling circuits 26 correspond to the unmixed DC reference signals (DC) of alternating current 1 (AC1) and alternating current 2 (AC2) from sources 68, 70 and 140, respectively.

The sensing coils 54 and 248 are connected to the resolver 224 via lines 168 and 172. The output of the sensing coil 52 and an output of resolver 224 are connected to resolver 226 via lines 166 and 174, respectively. A Output of resolver 224 and an output of resolver 226 are connected to resolver 228 via lines 176 and 178. The two outputs of the resolver 228 are connected to the Dissolver 230 connected via lines 186 and 188, respectively. An output of resolver 226 and an output of resolver 230 are connected to resolver 232 via lines 184 and 190, respectively. One output from the resolver 230 and two outputs from the trigger 232 represent the processed signal inputs of the sampling circuits 26 and are sent via lines 192, 194 and 196, respectively fed in. The sampling circuits operating on the three input signals mentioned above, which are on lines 194, 192 and 196 26, sample their deviations from the nominally correct values, the reference excitation signal components 68, 70 and 140 should correspond. The signal sampled on line 194 should nominally be a DC signal. If line 194 is an ac error signal at nutation frequency contains, then there is an alignment error, i.e. the alignment vector 180 does not exactly target the sensing coils 52, 54 and 248 is directed. That portion of the AC fault signal that appears on line 194 that is in the same absolute phase as the excitation signal 146 is proportional to an error in the directional angle A. This directional angle error in A is ver ~ with the angle measuring circuits 100 through line 200

- 26 509809/103 3

bound. The portion of the AC error signal that is on line 194 and is of the same absolute phase as the excitation signal 144 is proportional to the error in directional angle B. This error in the straightening angle B is connected to the angle measuring circuit 100 via line 202. The signal appearing on line .192 should be a nominal AC signal at the nutation frequency and not a DC signal. If a DC signal appears on line 192, it is proportional to an orientation angle error in angle γ , which is called the relative bearing angle. This detected error in the relative bearing angle r is connected to the angle measuring circuit by line 200. The signal that is present on the line should also be a nominal alternating current signal with the nutation frequency and contain no direct current component. Whenever a direct current signal appears on the signal line 1 $ 6, this is proportional to an error in the relative orientation angle -O-, which is the relative Is called elevation angle. This error in the relative elevation angle - <s> -. is fed to the angle measuring circuits 100 via line 206. As mentioned above, the nominal signals appearing on lines 192 and 196 are characterized not only by the fact that they represent an alternating current signal with nutation frequency, but also by the fact that they are in quadratic relation to their nominal reference signal counterparts alternating current 1 (AC1) and alternating current ( AC2). Furthermore, the phase difference between the signal on line 192 and the signal source 70 or, alternatively, the phase difference between the signal on line 196 and signal source 140 is proportional to an error in the relative orientation angle φ , which is the relative RoIl-

- 27 -

509809/1033

angle is called. This error in the relative roll angle φ is input to the angle measuring circuit 100 via line 204. The function of the angle measuring circuits 100 is to provide correct or "corrected" measurements of the two straightening angles A and B on lines 210 and 212 based on the angle errors detected by the sampling circuits 26. Another function of the angle measuring circuits 100 is to provide To provide correct or corrected measurements of the three relative orientation angles (/>, & and ir on lines 214, 216 and 218. These continually improved angle measurements "appearing on lines 210, 212, 214, 216 and 218 are through lines 234 and 240, 236 and 238, 246, 244, 242 are connected to resolvers 222 and 230, 220 and 232, 224, 226 and 228 in a fixed feedback arrangement. Corrections made by angle measuring circuits 100 in the respective angles are performed, act to reduce to zero the error signals j appearing on lines 194, 192 and I96 from the sampling circuits 26 It should be noted that the sequence of angles and their associated axes of rotation are not unique to both directional coordinate circuit 252p and orientation coordinate transformation circuit 250. That is, other angle definitions and rotation sequences can be used for either of the two transformations, provided they have the required freedom for alignment and relative orientation.

It is further indicated that the practice of the invention using known techniques with digital, analog or hybrid circuits can be carried out.

- 28 -

509809/1033

It should also be noted that although the invention is considered a unique transfer system with five degrees of freedom between two spatially distant independent coordinate systems, with only one generator source in one of the coordinate systems and only one receiver is used in the other coordinate system, this system can easily be extended to include a measurement of all six degrees of freedom using to achieve two producer funds. The second generating means would or could be at another point in the coordinate system of the first generating means and operating in parallel with the first generating means, the third Translation coordinate that of the relative area by triangulation using the same computational techniques, as used in the invention could be determined.

It should also be emphasized that the subject invention can be used in a wide range of applications can be used in ranges from a few cubic feet or less to applications in ranges of several cubic miles. It is after It is clear from the above description that the sampling circuits are internally connected to the components of the reference excitation signals from the Sources 68, 70 and 140 are supplied in order to be able to logically execute the filtered scan function which is required for their sampling circuits 26 is required.

The resolvers that represent parts of the circuit can for example, in accordance with the US Pat. 3,187,169 and 2,927,734. The sampling circuits, Again, for example, may be made in accordance with the teachings of the circuit diagram in the book "Electronics Circuit Designers

- 29 509809/1033

Casebook "by Electronics McGraw Hill, No. 14-6 on page 67 is shown. The angle measuring circuit can take the form of a large number of well known Type I servo mechanisms selected v / earth. There are of course numerous alternative designs available for each of these parts, as is readily apparent to those skilled in the art.

It should now be apparent that the inventive The system is capable of the tasks initially set for tracking and determining the position of a distant object can meet. The system and method of the invention uses a field for the purpose of accurately determining the Position and angular orientation of a distant object, which is relative to the coordinate system of the device, which the field generated. With a two-dimensional nutation of the generated field, the direction and orientation angles of the distant object can be determined in the plane of nutation. With a three-dimensional nutation, can the direction and orientation of a distant object can be determined.

An additional advantage of the invention is that (a) the raw output of the angle measuring circuit can also be useful in certain situations in an open system, although normally for an accurate determination of the angles j>, G and γ the generators directly on the scanning means must be directed, and that (b) the absolute location and orientation (including distance) of an object relative to the reference source by using two physically separated generators as shown in Figure 11 _; can be determined with suitable input and output circuitry on the object.

- 30 509809/1033

Although the invention in detail as a system for tracking the movement and orientation winkelmäss strength was a general- Lm remote object described, it is clear to the skilled person that the invention in a variety of Objektbestimmungs-, tracking and orientation ungs- Vv 'angle determinations can be applied. One application currently under development is the tracking of the movement / orientation of a viewing head, or in particular its line of sight, for use in a visually coupled control system. Other possible applications of, for example, the two-dimensional system arise in various types of surface transportation, such as maneuvering ships, or maintaining appropriate distances between passenger cars in an automated public transportation system. Other aircraft navigation problems that are suitable with the system of the invention to be solved, consist in the alignment of missile systems in the air, automatic coupling of the tanker nozzle and transducer when refueling aircraft, formation flying, instrument landing of aircraft taking off and landing vertically and the like.

Patent application:

509809/1033

Claims (11)

P a ten. T claims An object tracking system, marked η e t by means for radiating a directed nutation field around one representing the nutation axis Direction vector and located on the object means for scanning the nutation field, which may be on a existing misalignment of the directional vector is based and means for aligning the direction vector with the object in accordance with the error signal. 2. System according to claim 1, characterized in that the means for emitting the fields means for Generation of a direction vector with at least two independent components that have a function of at least are two primary reference signals and are means of transform! examg of the primary reference signals in accordance with assumed directional angle inputs to convert the directional vector into a To steer direction which corresponds to the assumed directional angle inputs, the scanning means comprising means for scanning of the field components that are generated by the nutation field around the direction vector and means for transforming of the sampled components in accordance with the assumed directional angle inputs, so as to reconstruct a set To obtain reference signals and.wherein the means for generating the signals from means for comparing at least some of the reconstructed reference signals with at least some of the primary reference signals to generate directional angle error signals and to change the directional angle input signals of the transforming means in accordance therewith to reduce the directional error to bring to zero. - 32 - 509809/1033 3. System according to claim 2, characterized in that that the directional field is an electromagnetic field and the means for radiating the field of orthogonal radiators and the primary reference signals are a DC signal and a first AC signal. 4. System according to claim 3, characterized in that the scanning means consist of orthogonal scanners. 5. System according to claim 4, characterized in that the object can move freely in two dimensions and can orient or rotate and that at least two orthogonal emitters and scanners for each of the emitting and scanning means are assigned and that the emitter and scanner lie in the area of the two dimensions. 6. System according to claim 4, characterized in that the object can move freely in three dimensions and can orient or rotate, with three orthogonal scanners and emitters assigned to each of the scanning and emitting means are unu where a second alternating current signal with the phase squared of the first alternating current signal, one of the represents primary reference signals. ·. 7. System according to any one of the preceding claims, characterized in that 'that means for determining the Orientation or rotation of the object are provided. 8. System according to claim 7, characterized in that that the directable field is an electromagnetic field, that the emitting means comprise three orthogonal radiators and that the scanning means comprise three orthogonal scanners and in that the primary reference signals are a direct current signal, a first alternating current signal and a second alternating current signal - 33 -509809/1033 with the squared phase of the first AC signal. 9. System according to claim 8, characterized in that that means are provided for determining the orientation or rotation of the object, that the determination means Means for analyzing two of the reconstructed reference signals are included to determine the orientation in two degrees of freedom and means for determining the phase relationship between at least one primary reference AC signal and the corresponding reconstructed AC reference signal are provided to the third degree of freedom of the orientation to determine. 10. System according to claim 9 »characterized in that that the directional error signals from the presence or absence of a variant of the reference signal in one of the reconstructed reference signals are determined, the two degrees of freedom of orientation or rotation by detection the presence of a DC razor signal in the other two reconstructed reference signals are determined. 11. An object tracking system according to claim 1, characterized in characterized in that it includes means for tracking the angular orientation of the object, and in that it further comprises means for generating a series of three primary reference signals; first means of transformation of the primary reference signals in accordance, with a first transformation, which is the assumed directional angle represents; Means, the three orthogonally aligned emitters for broadcasting the transformed have primary reference signals; Means consisting of three orthogonal scanners for scanning the transformed primary reference signals exist and said scanning means are permanently connected to the object and second means for transforming 509809/1033 - 34 - tion of the sampled signals are provided in accordance with a second transform which is the inverse represent an assumed set of orientation angles and third means for transforming the sampled signals are provided in accordance with a third transformation which is the reverse of the first transformation and Means for comparing the sampled and transformed with the primary reference signals and, if necessary, changing the assumed direction and orientation angles. 509809/1033 Blank page