DE3506216A1 - POSITIONING SYSTEM - Google Patents

Description

Dipl.-Ing. ■ - -

Tl .. 4 n «t,.«., ". 1t ■

Palentanwalt

Rehlingenstrasse 8 P.O. Box 260

D-8900 Augsburg 31

Telephone 0821/36015 + 36016

Telex 533275

PoMsthcdikciniii- Munich No. 1547 8 ') - 8OI

8910/149 -4_ Augsburg, the ch-ha

Smiths Industries Public Limited Company 765 Finchley Road

GB-London NWIl 8DS

Lagebest imm ungs syst e m

The invention relates to an orientation system for determining the location of a receiver relative to a receiver Channel.

Such a system can be used in particular in aircraft, in particular in helicopters, with it these occupy a constant position in relation to a point on the earth's surface, be it on water or on land can.

In certain cases it is important that a helicopter occupies a constant position in relation to the surface of the earth, for example in monitoring and air exploration, in air-sea operations, for example in rescue operations or when the helicopter is considered stable Platform should serve, such as for television cameras. It is not sufficient here to simply monitor the helicopter's attitude display, as others Influences determine the position of the helicopter, how for example the wind, updrafts, changes in engine power etc.

--5

Various proposals have already been made to keep a helicopter in an unchanged constant Able to hold. For example, it is possible to connect the helicopter to the earth with a rope, one end of the rope being attached to the ground and the other end being connected to a force measuring sensor that feeds signals to the helicopter's flight control system in accordance with that in the rope prevailing traction. In this way it is possible to control the helicopter so that the occurring in the rope Tensile force is essentially constant.

However, this method has a number of disadvantages. First, it is difficult to use such a system at sea, because this creates the problem of anchoring the cable on the water surface. It is still dangerous to take a helicopter on to secure this way, since this limits the manual control of the helicopter and also the Blade control can get out of control. Furthermore, it is difficult to maintain a constant angular orientation of the helicopter to be maintained in relation to the earth-side fastening end of the rope. In gusty wind conditions, the application is this system is also excluded.

In order to avoid the connection of the helicopter to the earth by a rope, it is also known to use the Earth's surface with an optical sensor, such as a television camera to monitor. Correction signals are fed to the control of the helicopter, in Correspondence with changes in the image received by the sensor, which caused by movements of the helicopter. This can

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are done by looking at the normal surface of the earth or alternatively by dropping a colored or illuminated marking on the earth's surface in the Field of view of the sensor. This system is used especially at night or in areas with a regular topography, such as desert or Water. Although this system has a number of advantages, it is disadvantageous that it is relatively expensive is due to the complexity of the structural components that detect changes in the field of view of the sensor and should evaluate. This system has the further disadvantage that it cannot be used in poor visibility conditions is where the sensor has no clear field of view of the ground. There are also use cases where the Use of the system is excluded, for example at night when an illuminated marker is used must be, since this allows the position and position of the helicopter to be detected, but this is hidden should stay.

The task is to train the position determination system so that regardless of environmental influences The position of the receiver relative to the transmitter can be determined without the latter being optically locatable.

This object is achieved with the characterizing features of claim 1. Advantageous embodiments can be found in the subclaims.

A major advantage of the system is to be seen in the fact that the position can be determined at any angular Orientation of the transmitter is possible, which is of particular value when the transmitter is from an airplane is thrown off.

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The position determination system in its application in a helicopter is illustrated below with reference to the drawings explained in more detail. Show it:

1 shows a helicopter in a position relative to a transmitter on the earth's surface;

2 shows an illustration of the transmitter;

Fig. 3 is an illustration of the receiver attached to the helicopter and

4 vector diagrams of the transmitter and the receiver.

Fig. 1 shows a transmitter unit 1 on the ground 2 and a helicopter 3 with a receiver unit 4, which Signals the flight control system 5 feeds. The flight control system 5 keeps the position of the helicopter 3 in relation to the transmission unit 1 constant by appropriate control of the rotors 6 and 7 of the helicopter.

As can be seen in FIG. 2, the transmission unit 1 has three electrical coils 10, 11 and 12, the Axes 13 to 15 are arranged at right angles to one another. The coils 10 to 12 have a circular shape Cross-section and can be about learning long. Their outer radius is 5cm and the inner radius is 4cm. the Dimensions of the coils can also be different and are determined by the specific application and through the available drive power. The coils 10 to 12 are held in their perpendicular position to each other by non-magnetic cores 16 to 18.

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Each coil 10 to 12 is assigned a transmitting or energizing circuit 20 to 22, each of which is from a battery 23 are fed. Each transmission circuit 20 to 22 applies an alternating voltage of constant Frequency f ,, f «and f ^ to one of the coils 10 in each case to 12, so that each of the coils emits an electromagnetic radiation at a certain frequency, which is different from the frequency of the other two coils. The radiation from the transmitter unit 1 is planting along the axes 13, 14 and 15 of the coils 10 to continue. For short distances, i.e. in the range of a few a hundred meters the induction field outweighs the transition field and the radiation field. For example, is at a distance of 10m from a small coil the field distribution ImV for the induction field, while the transition field 300 nV and the radiation field 100 picovolts. At a distance of 100m, the strength of the induction field is ImV, that of the transition field 3nV and that of the radiation field IOPikovolt. The signal strength of the induction field changes inversely proportional to the cube of the distance from the coil. The fact that the signal strength is attenuated rapidly as a function of the distance only makes the system applicable for relatively short distances, since interference has a strong influence at greater distances. this however, it has advantages in those applications where it is desirable to go undetected.

The coils 10 to 12, the cores 16 to 18, the transmission circuits 20 to 22 and the battery 23 are in one Housing 30. The housing 30 is designed to withstand damage that could occur

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when the transmitter unit 1 is dropped from an aircraft. So the contents of the case must be strong Withstand impact undamaged, the transmitting device is for this purpose in the housing 30 preferably of a deformable support 31 carried, which is elastic or which is compressible and able to absorb strong impacts. For example, the carrier 31 can be made from consist of a rigid foamed material or a honeycomb material. Alternatively it can come from a liquid-filled cylinder and a piston, the latter pushing the liquid out of the cylinder when the cylinder is hit works. The housing 30 is made of a squeezable material. Alternatively or additionally, the housing 30 be surrounded by a cover which is inflated when the transmitter unit is thrown from the aircraft and which is inflated when it hits the ground. There are several other ways that corruption can occur of the transmitter unit 1. The damage to the transmitter unit 1 can continue to be largely due to this be avoided that it is slowly lowered to the bottom. This can be done, for example, that the unit 1 is lowered from the aircraft by a rope.

If the transmission unit 1 is to be thrown onto the ground, the housing 30 preferably has a tetrahedral shape on, thereby reducing the risk of the transmitter unit rolling on the earth. Alternative forms of housing are also possible, for example, the housing can have suitable projections that go into the ground penetrate and in this way prevent the transmitter unit 1 from rolling away.

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If the transmitter unit 1 is lowered onto water, then the housing is preferably designed so that ensures that the pools are above the surface of the water. The housing can have a weighted keel, for example, so that the Rolling of the transmitter unit in rough seas is reduced.

The housing can be a camouflage color or a contrasting color have, depending on whether it is desirable that the housing be visible or invisible. The case can also be designed so that it can be detected by a radar field.

As can be seen from FIG. 3, the receiver unit 4 has three coils 40, 41 and 40, which are circular in cross section which are arranged at right angles to one another, see the axes 43, 44 and 45. That in each of the coils 40 to 42 induced signal is "via shielded lines 46 to 48" to a discriminator 49 to 51 in each case fed within a process unit 52. The discriminators 49 to 51 contain frequency-selective circuits, generate the signals related to the signal strengths of the frequencies f ,, fp and f i. Each discriminator 49 to 51 generates three signals on lines 53A to 53C, 54A to 54C and 55A to 55C which are applied to the inputs of a computer 56 lead. The computer 56 is thus fed to nine signals whose amplitude is measured and used to calculate the Position of the receiver 4 relative to the transmitter 1 can be used.

The nine input signals are used to solve nine equations with nine unknowns, as will be explained later.

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The computer unit B6 calculates the position of the receiver 4 relative to transmitter 1 and compares this position with a previously selected position (target position). Is there a Difference between these two positions, then the computer unit calculates the necessary changes, which must be carried out by the helicopter control in order to correct this difference and thus to bring the helicopter into the target position. Signals in accordance with these control variables are transmitted via the line 57 is fed to the computer 56 from the flight control system 5.

The coils 40 to 42 and the associated processing unit are below the helicopter 3 outside of it Metal skin 58 arranged. These components are from one Protective housing 59 made of plastic or some other non-shielding material surrounded.

The receiver 4 and the transmitter 1 are calibrated with respect to one another before use. The transmitter 1 turned on before ejection from helicopter 3. The pilot then controls the helicopter in the area within the helicopter from 100m from the point of impact of transmitter 1 in the desired position, then actuates a switch 60, so that the computer 56 thus the Determined position of the helicopter 3 relative to the transmitter 1. This is the target position. The orientation system this target position is retained in the computer 56, compared with the actual position and generated Corresponding correction or control signals that the Flight control unit 5 are supplied when target and Actual positions do not match each other. The helicopter 3 is preferably at a constant altitude held, for example by means of a conventional gyro

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stabilization control system 70.

A brief summary of how the helicopter attitude is determined is given below.

Three mutually perpendicular axes are represented by the unit vectors i »j, k in FIGS. 4 and 5 given. The unit vectors i and j lie in a plane parallel to the ground, while the unit vector k is behind below shows. The unit vector i is aligned with the required heading of the helicopter 3. The den The helicopter's heading-determining controls are assumed to be locked. Changes to the Required heading of the helicopter 3 can be controlled by a magnetic or gyro compass Getting corrected.

For the transmitter 1, the three coils 10 to 12 arranged at right angles to one another can be viewed as three independent dipoles m ^ m ₂ and nu, which start from the center 0, 0, 0. It is assumed that these three dipoles m ₁ , m 2 and nu originally run along the axes i, j and κ, then the transmitter unit 1 is _{rotated by an angle r T} about the dipole axis nu, then by an angle 0y about the dipole axis nu and ultimately by an angle 0j around the dipole axis m. The three angles ' Yj, Qy and j3y are random and can change as a function of time, as is the case with an application at sea.

The dipole m ^ has components in the axes i, j and k on, which are denoted by m, m and m dies

means as a vector formula:

ι ι

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8910/149
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. = mi + m j i ^y i

+ m k

where i = 1, 2,

Expressed in a matrix this means:

^m x ^m x ^m X ₁ x ₂

^ra v ^m v ^{m y} 1 ^y 2

2 ^Z 3 OO

OOm-

whereby

0 0 CCS * « -slr. 4 sir-4 1 0 ccs.i 0 1 -sir.e ^ .0 0 0 "COSS ^ sin ** COSG ₀ , 0 COZY _- . O" .sine. 0 O ; ccs ^ 1 -sin ^ 0

... (IiI)

(V)

and ok = T is.

The undimensioned dipole NL is given by

M ₁ = M _y .i + M _v -j + M .k ι ^x i ^y i ^z i

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whereby

= m / m. X ι

M = m / m.

z.

with i = 1, 2, 3,

As a matrix equation, this means

M M M

X X

... (VII) ... (VIII)

The magnetic field at position r of the receiver 4 with

r = xi + yj + zk as a result of the dipole m ₁ is given by:

m. - 3 (m..r) r Dl ₁ Dl ₁ ^

Po H \

C7l

^M i -

j + B k ^z i

where i = 1, 2, 3.

Assume that the three are at right angles to each other standing receiver coils 40 to 42 with the helicopter

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axes i ¹ , j ¹ and k 'are aligned as shown in FIG. The helicopter axes i ¹ , j ¹ and k ^{1 are} originally aligned with the unit vectors i, j and k. The helicopter axes are then rotated by an angle by k ', then by an angle 0 by j ¹ and finally by an angle 0 by i ·. The vectors i ¹ , j 'and k ^{1 are} the longitudinal, transverse and vertical axes of the helicopter and V »θ and {3 are the angles of roll, tilt and yaw of the helicopter.

With V ₁ , V ₀ and V ₀ are those in the receiver coils

¹ IM ³ i

40, 41 and 42 denoted induced signal strengths, assigned to the dipole m-, the frequency of which is fj. as The matrix equation then applies

.. (XII)

where i = 1, 2, 3 and (jzfj, £ pj , [JpJ are defined by equations III, IV and V.

The nine induced signal strengths are dimensioned as follows:

... (XIII) -16-

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where i = 1, 2, 3.

Provided that the helicopter 3 is stabilized in a horizontal position and on the course direction, then means this:

g_Q_ ^/ U / _n f VTW \

ψ VJ \ J ι <ι ^ Λ1 VJ

Then:

¹ V

M.

- 3 (M _5. X + K y + M "z) x / A ■ * ii

3 (Μ _χ χ + My y + M ₂ z) y / r

3 (M χ + M y + M, z) z / r ^{2 x} i ^y i ^z i

.. (XV)

where i = 1, 2, 3.

Equation XV represents nine non-linear equations with nine unknowns, which are x, y and ζ and from equation XIII the quantities sin0 _T , cos0 _T , sinO ,. cosQ-j., sinV _T , cosVj.

These nine equations have an explicit solution. Equation XV can also be represented by:

PM

... (XVI)

where A is the matrix of the nine measured values of the receiver coils 40 to 42 recorded according to size. This means:

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and

A =

P =

^β 1 ^a 2 ^a 3

^b 1 ^b 2 ^b 3 C ₁ C ₂ C ₃

Ί-3Χ ² -3XY

-3XY 1-3Y ²

-3XZ -3YZ

-3YZ
.-1-3Y ²

... (XVII)

... (XVIII)

where X = x / r
Y = y / r
Z = z / r

and X ² + Y ² + Z ² is.

= 1 ... (XIX)

... (XXI)

... (XXII)

It shows, that

3 3 i = l j = l

r ⁶ = 4

- ¹ H, 3) J (... XXIII)

where A (i, j) is the value of the element in the series i and column j of the inverse matrix of A.

For the equation

IT XY XZ

XY Υ ² YZ XZ YZ Z ²

= 4 ί! - ([Α] " ¹ ) ^T ί> ³ ΑΓ ¹ } ... (XXIV)

T represents the transpose operator and I the identity matrix.

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Knowing the sign of ζ, which is negative when the helicopter 3 is above the transmitter 1, allows the determination of x, y and ζ from equations (XXIII), (XXIV), (XIX), (XX) and (XXI). The values of x, y and ζ define the position of the receiver 4 relative to the transmitter 1.

The above solution involves determining the orthogonal property of the M matrix (VII) without the need for it is to solve the matrix M explicitly. The solution is regardless of the orientation of the transmitter 1. One rotation of transmitter 1 at time intervals between each The set of nine simultaneous measurements does not affect the particular position of the receiver 4. The system therefore has particular advantages where the transmitter 1 is located on a moving surface, such as for example on the water or a moving object. The system enables the helicopter to have a constant High above a wave during an air-to-sea rescue operation maintains. The system enables ■ to facilitate the landing of an aircraft on a moving surface, such as the deck of a ship, when the transmitter is is on the moving surface. In a further embodiment it is possible that the transmitter 1 only sends when an activation signal is supplied to it from the helicopter 3. The system is still useful for precise positioning of an aircraft relative to another, with one aircraft carrying the transmitter 1 and the other aircraft carrying the receiver 4, for example when refueling in the air.

Claims (12)

DipL-lng. - - Patent attorney Rehlingenstrasse 8 ■ Postfach 260 D-8900 Augsburg 31 Telephone 08 21/3 6015 + 3 6016 Telex 53 3 275. , - · .. ·,. . · R. . -. Λ piMschuckkonio Munich Nr IM-X9an Note: Smiths Industries Public Limited Company 8910/149 Augsburg, the Ali s pr Up he 1. Position determination system for determining the position of a receiver relative to a transmitter, characterized in that the transmitter (1) has three individual transmitters whose transmission beam directions are perpendicular to one another and whose transmission frequencies (f ,, f ₂ , fg) are different from one another, that the receiver (4) has three directional receivers, the receiving directions .rechtwinklig to each other and that a measuring circuit (56) is provided which measures the _v received signal amplitudes of each of the three frequencies (f ,, f ₂ , f ₃ ) from each of the three directional receivers and from this the position of the receiver (4) relative to the transmitter (1) is determined. 2. Position determination system according to claim 1, characterized in that the transmitter (1) has three electromagnetic transmitter coils (10, 11, 12), the axes (13, 14, 15) of which are perpendicular to each other, to which constant alternating current signals of different frequencies (f ^, f ₂ , f ^) are supplied and that; the receiver (4) has three electromagnetic receiving coils (40, 41, 42), the axes (43, 44, 45) of which are perpendicular to one another. 3. Location system according to claim 2, characterized in that g e - k e η η ζ e i c h η e t that each transmitter coil (10, 11, 12) -2- f a transmission circuit (20, 21, 22) is assigned. 4. Positioning system according to claim 2, characterized in that each receiving coil (40, 41, 42) is connected to a frequency discriminator (49, 50, 51) which generates three output signals, each of which is proportional to the strength of the received signal at one of the Transmission frequencies (f ,, f «, f ₃ ) is. 5. Position determination system according to one of claims 2 to 4, characterized in that the cross section of the coils (10, 11, 12, 40, 41, 42) is circular. 6. Position determination system according to one of claims 2 to 5, characterized in that the coils (10, 11, 12) of the transmitter (1) are arranged on an elastic carrier (31). 7. Position determination system according to one of claims 1 to 6, characterized in that the transmitter (1) with its coils (10, 11, 12) in a housing (30) is arranged, which is deformable. 8. Position determination system according to one of claims 1 to 7, characterized in that the transmitter (1) is arranged with its coils (10, 11, 12) in a housing (30) which is essentially tetrahedral is trained. 9. Position determination system according to one of claims 1 to 8, characterized in that the transmitter (1) is arranged in a floating housing (30), -3- 8910/149 -3- ocncoic in which in the floating state the coils (10, 11, 12) are above the water surface are located. 10. Orientation system according to claim 9, characterized in that the floating housing (30) has a weighted keel. 11. Position determination system according to one of claims 1 to 10, characterized in that the transmitter (1) as a function of an activation signal of the receiver (4) electromagnetic waves sends out. 12. Position determination system according to one of claims 1 to 11, characterized in that the Receiver (4) is arranged on an aircraft (3), the measuring circuit (56) with the aircraft control device (5) is connected, the target position of the aircraft (3) by holding the new measured values when a key is pressed is set and the measuring circuit (56) of the flight control device (5) supplies command signals when the new measured values currently received from the at Pressing the key reached the recorded measured values.