DE3019372C2 - Self-aligning course reference device - Google Patents

Description

The invention relates to a self-aligning course reference device for the navigation of a vehicle, in which the north direction due to an initial alignment determined and then in course reference mode for the

* Navigating continuously a heading angle is tapped, containing: an azimuth frame around an azimuth axis is rotatably mounted, a two-axis gyro which is arranged on the azimuth frame, wherein the spin axis of the gyro lies in a plane perpendicular to the azimuth axis, a first plane Entry axis of the gyro parallel to the azimuth axis

so and the second input axis of the gyroscope is perpendicular to the spin axis and the first input axis, first and second taps on the first and second input axes, respectively, of the gyro, first and second torque generator on the first and second input axis of the gyro, the one on the Second input axis arranged second tap is connected to the first torque generator, which is on the first input axis of the gyro sits, and the signal switched to the first torque generator for the initial alignment is at the same time due to north-determining means, a servomotor for rotating the azimuth frame around the azimuth axis and one arranged on the azimuth axis Angular position transmitter.

Ej is a device for navigating land vehicles known (DE-OS 25 45 025), in which by means of a tape-suspended meridian gyro, its directional moment is compensated by a counter-torque, the

• The angle between the gyroscopic axis and the north direction is determined. A free gyro used for navigation of the vehicle serves as a course reference device, it is aligned according to the north direction determined in this way. A Such a self-aligning course reference device works with two steps: Before starting the journey, the North direction determined The course reference device is initially aligned according to this north direction. The course reference device then continuously supplies the heading for this north direction in course reference mode related course of the vehicle.

From DE-OS 27 41 274 it is known to use the north direction instead of a tape-hung To determine gyroscope with a horizontal twist axis with the help of a two-axis rate gyro, its The twist axis is arranged vertically. The rate gyro contains on two mutually perpendicular, horizontal ones Input axes each have a tap and a torque generator each. The output signals of the taps are in each case crosswise via an amplifier to the torque generator on the other input axis switched. The signals switched to the torque generators correspond to the components the horizontal component of the earth's rotation. The initial value of the course angle results from the ratio of the two signals. About this initial value too then to get correctly if the gyroscopic axis, which extends in the direction of the vehicle vertical axis, does not is exactly vertical to the earth's surface, two accelerometers are provided, which the incline of the vehicle. From the signals from the accelerometer and from the two torque generators of the rate gyro applied signals is in a computer the initial value of the determined on a fixed coordinate system related course angle

In the arrangement according to DE-OS 27 41 274 is the same two-axis rate gyro after pivoting by 90 ° with a substantially horizontal Gyroscopic axis used as course-position reference device, the computer from the angular velocities and the accelerometer signals taking into account the initial alignment determined initial values constantly the position of the vehicle and in particular continuously the true course angle calculated

In both cases, the heading angle and the vehicle speed measured in the vehicle's longitudinal axis are used determines the position of the vehicle in a geographic or grid coordinate system

The known arrangements described provide the vehicle position with a high degree of accuracy however, too complex for many applications, while on the other hand there are applications in which the The requirements for the accuracy of the navigation are lower, but a less complex course reference device is required.

The patent application P 29 22 41Z2-52, which was not previously published, is a self-aligning course-position reference device known in which the north direction is also determined by an initial alignment and then a course angle is continuously tapped in the course reference mode for navigation. The known Course reference device contains an azimuth frame, which is mounted on the rotatable about an azimuth axis Azimuth frame is a biaxial gyro arranged with the spin axis of the gyro in one to the A first input axis of the gyro lies parallel to the azimuth axis in the plane perpendicular to the azimuth axis and the second input axis of the gyro is perpendicular to the spin axis and the first input axis A first and a second tap are located on the first and second input axis of the gyro. Further sit on the first and second input axis of the gyro, a first and a second torque generator respectively. Of the The second tap located on the second input axis is on the first torque generator ίο switched, which sits on the first input axis of the gyro. That on the first torque generator The switched signal for the initial alignment is switched on at the same time to means that determine the north direction The azimuth frame can be rotated around the azimuth axis by means of an actuating motive. Furthermore, on the Azimuth axis arranged an angular position sensor

In the known self-aligning course / position reference device, the azimuth frame is in a roll frame mounted rotatably about the essentially vertical azimuth axis, and the rolling frame is in turn Swivel-mounted around the vehicle's longitudinal axis. The two-axis gyro is a two-axis spiral gyro. It is not only the second tap that is connected to the first torque generator, but similarly to how in DE-OS 27 41 274, also the seated on the first input axis first tap on the second input axis of the gyro seated second torque generator. Finally sitting on the azimuth frame Another accelerometer, the input axis of which is parallel to the spin axis of the gyro

The azimuth frame is with the roll frame in a first operating mode "northing" or "initial alignment" so orientable about the vehicle longitudinal axis that the azimuth axis in a through the vehicle longitudinal axis The azimuth frame is included in a second operating mode, "course-position reference" the roll frame can be aligned around the longitudinal axis of the vehicle so that the azimuth axis is parallel to the vertical axis of the vehicle is

The azimuth frame can be rotated by the azimuth servomotor around the azimuth axis, either in a 0 ° position, in which the twist axis is parallel to the longitudinal axis of the vehicle, or in a 90 ° position offset by 90 °.
The signals from the rate gyro and the accelerometer are connected to a computer

In the first "Norder" operating mode, the computer delivers from the in both positions of the Azimuth frame measured and stored, the so rotational speed around the second input axis reproducing signals of the rate gyro and those also measured and stored in these positions Acceleration signals of the accelerometer the initial deviation of a through the Vehicle longitudinal axis extending vertical plane from the meridian plane (initial north deviation).

In the second mode of operation »Course-Position-Reference«

When turning the azimuth frame into the 90 ° position, the computer delivers from the angular velocity signals the rate gyro a signal that reflects the true course of the vehicle.

In this known arrangement, as in DE-OS 27 41 274, both the north direction in the Initial alignment as well as the course angle in the "Course-Position-Reference" mode of operation by one Computer from the two signals of the two-axis rate gyro and accelerometer signals calculated The advantage of the arrangement according to patent

message P 29 22 412.2-52 is that with favorable mechanical effort a considerable simplification of the signal processing compared to the arrangement DE-OS 27 41 274 is achieved.

Here too, however, the effort for many applications is still too high, while the achievable Accuracy is not even needed in some cases.

The invention is therefore based on the object of creating a self-aligning course reference device which is so inexpensive that the use of navigation devices of the present type is widespread, for example in battle tanks.

According to the invention this object is achieved in that

(a) the tap located on the first input axis of the gyro is switched to the servomotor is,

(b) on the second torque generator arranged on the second input axis of the gyro Course reference mode a signal can be switched on, which is the vertical component of the earth's rotation reproduces, and

(c) the course signal for the navigation in course reference mode from the azimuth angle encoder below Taking into account the north direction determined during the initial alignment.

In course reference mode, the arrangement works like a single-axis platform. If you have the Regards the azimuth axis as exactly vertical and no frictional influences would occur, the Azimuth frame maintains its position in space when the vehicle is moving. On the azimuth angle encoder the heading angle could be read. But since the effects of friction are not negligible, the The azimuth frame is twisted when the vehicle rotates The first input axis is a free top that seeks to maintain its position in space, a signal arises? in the first tap, which holds the azimuth frame in its position in space through the azimui sleümötor That is the function of a single axis platform.

The second input axis of the gyro is used for initial alignment, the gyro around this axis by switching the signal from the second tap to the first torque generator around this The input axis is electrically tied. The signal switched on the first torque generator is supplied a component of the earth's rotation and can therefore be used to determine north direction. at This signal is irrelevant for course reference operation. It is only used to tie the top to one defined position aiu the second input axis,

The second torque generator, which is located on the second input axis, is used in course reference mode, So during the navigation, a signal is switched on, which is the vertical component of the Earth's rotation corresponds, so the azimuth frame that yes would seek to maintain its position in space, turned according to the rotation of the earth and in is held in a defined position to the north.

The arrangement described provides an extremely simple course reference device that is suitable for mass use is suitable and ensures sufficient navigation accuracy

Further refinements of the invention are the subject of the subclaims.

Two embodiments of the invention are set out below with reference to the associated Drawings explained in more detail:

F i g. 1 is a schematic perspective illustration of a first embodiment of the self-assembling Course reference device;

F i g. 2 illustrates the relationship between the course and attitude angles in the vehicle-fixed and the earth-fixed coordinate system;
F i g. 3 shows the structure of a

form according to Fig. 1 used signal evaluation circuit for initial alignment;

F i g. 4 shows schematically the formation of the course angle signals in course reference mode during navigation;

5 is a schematic perspective illustration a second embodiment of the self-aligning course reference device;

Fig. 6 shows the dependency on the first Torque generator applied signals from the position of the azimuth frame;

F i g. 7 shows in four quadrants the dependence of the in the direction of the second input axis of the gyro measured component of the earth's rotation at the various positions of the azimuth frame North direction.

The self-aligning course reference device of FIG. 1 contains an azimuth frame 12 rotatably mounted about an azimuth axis 10 that is fixed to the device or vehicle. A two-axis gyro 14 is arranged on the azimuth frame 12. The twist axis z ^{K of} the gyro 14 is arranged in a plane perpendicular to the azimuth axis 10. A first input axis y * of the gyro 14 runs parallel to the azimuth axis 10, and the second input axis x ^{K of} the gyro 14 runs

perpendicular to the twist axis z ^K and the first input axis y *. A first tap 16 and a first torque generator 18 are arranged on the first input axis y *. A second tap 20 and a second torque generator 22 are arranged on the second input axis x ^K

The second tap 20 arranged on the second input axis x ^K is connected via an amplifier 24 to the first torque generator 18, which sits on the first input axis j * Das of the amplifier

24 signal T ₂ connected to the first torque generator 18 is, as will be described, for the initial alignment simultaneously connected via filter 26 as signal Ti to means determining the north direction.There is a servomotor 28 for rotating the azimuth frame 12 about the azimuth axis 10 and one on the azimuth axis 10 arranged angular position transmitter 30 is provided in the form of a resolver.

The tap 16 arranged on the first input axis y * is connected to the via an amplifier 32

Servomotor 28 switched when the azimuth frame 12 rotated around the azimuth axis 10 relative to the gyro 14, which results in a signal at the tap 16 then this rotation is carried out via the servomotor 28 corrected

On the second torque generator 22, which is arranged on the second input axis x ^K , a signal can be applied via a switch 34 and an amplifier 36 during course reference operation, which again the vertical component ßfsin Φ of the earth's rotation.

where Ω ε is the rotational speed of the earth and Φ is the geographical latitude

The course signal for the navigation is in course reference mode in a manner to be described by the

230242/610

Azimuth angle encoder 30 taking into account the at the initial orientation determined north direction.

In the embodiment according to FIG. 1, instead of the signal reproducing the vertical component of the rotation of the earth, via the switch 34 and a selector switch 38, optional signals can be switched on for the initial alignment on the torque generator 22 arranged on the second input axis x ^{K, which signals from the deviation of the angular position measured by the azimuth angle encoder 30} Azimuth frame 12 depend on predetermined 0 °, 90 ° or 180 ° positions, with the twist axis z ^{K of} the gyro 14 being parallel to the vehicle longitudinal axis x9 ~ * x ^F in the 0 ° position. An accelerometer 40 is on the azimuth frame 12 arranged, whose input axis is parallel to the twist axis z ^{K of} the gyro 14. Instead of the accelerometer, a level could also be provided.

In the embodiment according to FIG. 1, a signal evaluation circuit (FIG. 3) is provided as the north-direction-determining means, containing memories 42, 44, 46 in which the signals T ₂ , which are transmitted to the first torque generator located on the first input axis y * of the gyro 14 18 are switched on, can be stored in the 0 ° position, the 90 ° position or the 180 ° position. The signal evaluation circuit also contains memories 48, 50, 52, in which the signals of the accelerometer 40 in the 0 ° position, the 90 ° position or the 180 'position can be stored. Finally, a computer circuit 54 is provided for forming the sine and / or cosine of the initial value ψ (0) of the course angle ψ from the stored signals.

For a better understanding of the mode of operation of the computer circuit, the relationships are shown in FIG between the course and attitude angles and the transformation parameters between the vehicle-fixed and the earth-fixed coordinate system.

The vehicle-fixed coordinate system contains the coordinate axes x ^F (vehicle longitudinal axis), J ^ (driving

vehicle transverse axis) and z ^ vehicle vertical axis). The earth-fixed coordinate system contains the coordinate axes x ^R (north), y * (east) and z ^R (vertical). The vehicle-fixed coordinate system is converted into the earth-fixed coordinate system by a rotation around the roll angle φ around the vehicle's longitudinal axis x ^F , a rotation around the then obtained vehicle transverse axis by the pitch angle # and finally a rotation of the vehicle's longitudinal axis, which is now in the earth-fixed horizontal plane, around the heading angle φ, whereby the longitudinal axis of the vehicle with the

Earth- fixed coordinate axis x ^R coincides The relationship between the vehicle-fixed coordinate system and an earth-fixed coordinate system is given by the transformation parameter matrix

cd c ψ CD s ψ -s δ

-S ψ

C 9 S 9

C. 9

S. δ

C. ψ

S. δ

C. δ

C ψ

S 9 S δ

-S 9 ep C 9 ^s &

C 9 C 9

C φ

S ψ

The connection between the Lsgewinke! φ, δ and ψ with ie «elements of the transformation» parameter matrix is 9

aresin C ₃₁ , Nick

arctan

arctan

, Greed (course)

, RoU

45

The vector of the rotational speed of the earth in which the associated signals of the acceleration measurement

Earth-based coordinate system has a horizontal 50 sers 4 · have the following form: Component -

r, _n * Α. - S (O) - g + B _x

Oe = OECOSV -,

A ^c _x " w (O) g + B _x

and a vertical component -j _c "

- ^ 11W

-J (O) g + B _x

These components are also shown in Figure 2 The acceleration due to gravity # represents a vector that acts in the vertical direction z *

It can be shown that the signals Ti obtained in the 0 ° position, the 90 ° position and the 180 ° position to the first torque generator 18 have the following form for small pitch and roll angles:

-b _x

- sin ψ (0) flc + F (O) O _s ~
_w - cos ψ (0) · Oc + « (0) Qs- 3J | _1M - -sin 9 (G) ü _c -w (P) · O

Here b _{x is} the drift of the top. B _x is the basic error of the »escbleuMfHOgseesser.

The computer circuit extracts values for sinip (O) and cosip (0) from the aforementioned signals Eliminate gyro drift and accelerometer zero error 40 and below Consideration of the position angle.

For this purpose the computer circuit contains

Mean 56.58 to form the negative mean of the

on the first torque generator 18 in the

0 ° position and in the 180 ° position switched to

and signals stored in memories 42 and 46,

whereby a signal B _x reproducing the drift b _{x of} the gyro 14 about the second input axis x ^K is obtained. The computer circuit also contains means 60, 62 for forming the mean value of the accelerometer 40 signals stored in the memories 48, 52 in the 0 ° position and in the 180 ° position, whereby a signal S representing the zero point error B _{x of} the accelerometer 40 _{x is} obtained. Means 64 are provided for subtracting the zero-point error signal B _x from the signal of the accelerometer 40 stored in the 0 ° position, as a result of which a first corrected acceleration signal is obtained. Means 66 are also provided for multiplying the first corrected acceleration signal by the ratio

Qs
Q

the vertical component ß _{s of} the earth's rotation and the acceleration due to gravity g to form the product ■ & {0) ■ ßj of the initial value ^ (0) of the pitch angle and the said vertical component ß _s .

The computer circuit also contains means 68 for adding the stored signal applied to the first torque generator 18 in the 90 ° position and the drift signal b _x and for subtracting the product ^ 0) · ß _s of the pitch angle and the vertical component of the rotation of the earth, whereby a first Sum signal is generated, and means 70 for dividing the first sum signal by the horizontal component β _{c of} the earth's rotation, whereby a signal cos v (0) representing the cosine of the initial value of the heading angle is obtained.

The computer circuit further contains means 72 for subtracting the zero point error signal B _x from the signal of the accelerometer 40 stored in the 90 ° position, whereby a second corrected acceleration signal is obtained, and means 74 for multiplying the second corrected acceleration signal by the ratio

Qs

the vertical component ß _{s of} the rotation of the earth and the acceleration due to gravity g to form the product of the initial value <p (0) of the roll angle and the said vertical component ß _{s of} the rotation of the earth. There are means 76 for adding the stored signal applied to the first torque generator 18 in the 0 ° position, the drift signal b _x and for subtracting the product <p (0) - ßj from the initial value of the roll angle and the vertical component of the rotation of the earth, whereby a second sum signal is generated, and means 78 for dividing the second sum signal by the horizontal component ß _{c of} the earth's rotation, whereby a first, the sine of the initial value of the course angle representing signal sinip (O) | o is obtained.

This means that signals are available that correspond to the sine and cosine of the initial value of the course angle represent.

The computing circuit preferably also contains means 80 for adding the stored signal applied to the first torque generator 18 in the 180 ° position, the drift signal b _x and the product <p (0) · ß _s of the initial value of the roll angle and the vertical component of the Rotation of the earth, whereby a third sum signal is generated, and means 82 for dividing the second sum signal by the negative horizontal component -β _{c of} the rotation of the earth, whereby

a second signal sinip (O) | ieo representing the sine of the initial value of the heading angle is obtained. It are means 84, 86 for forming the mean value of the first and the second, the sine of the initial value of the course angle representing signal provided, the

ίο as a useful signal sin "φ (0) at the output of the computing circuit 54 appears

As shown in FIG. 4 as can be seen, the azimuth angle encoder is a resolver, which supplies output signals corresponding to the sine and cosine of the angle of rotation λ _ζ as analog signals with 400 Hertz. An analog-to-digital converter 88 is provided which digitizes the output signals of the resolver. Furthermore, Winkeladditionsmittei 90,92 are provided, which the digitized output signals of the resolver and the in

Registers 94, 96 stored sine and cosine of the initial value of the course angle are fed and which provide output signals which represent the current course angle.
A two-pole switch 98 is in the "initial alignment" mode of operation in switch position "1", that is, open, while it is closed in switch position "2" in course reference mode. The switches 100 are intended to indicate that the output signals sin (nT) and cos (nT) are generated digitally with a cycle time T.

F i g. 5 shows a modified embodiment of the self-aligning course reference device. The basic structure is the same as the heading reference apparatus of Fig. 1 and corresponding parts are the same Provided reference numerals as there.

^ s As from F i g. 1 and F i g. 5, a fixed coordinate system with the coordinate axes x °, y ° and zP is defined by the course reference device. This device-fixed coordinate system expediently coincides with the vehicle-fixed coordinate system

x ^F , y ⁷ and z ^F together. The azimuth frame defines a coordinate system xP, y °, zP , the twist axis z ^{K of} the gyro 14 falling in the direction of the coordinate axis xP , the first input axis y ^K in the direction of the coordinate axis zP and the second input axis x ^K in the direction of Coordinate axis y °.

6 shows the dependence of the signal T ₂ supplied to the first torque generator 18 on the angle between the gyroscopic twist axis or the gyroscopic twist vector and north direction. The following relationships result for the various quadrants:

I. Quadrant: -T ₂ = -Q _c -s \ nx + b _x

II. Quadrant: - T ₂ = -ß _c - sina + ö »
HI. Quadrant: - T ₂ = ß _c · sin α + b _x

IV. Quadrant: - T ₂ = ß _c · sin «+ b _x

Here, κ is the angle that results from the sine table for the respective amount of the signal T ₂

The relationships are shown in FIG. 7, t_ is the reference direction in relation to which the azimuth angle λ _{ζ is} measured and which, for example, coincides with the xP or x ^F direction ß _c is the horizontal component of the earth's rotation. The gyro responds to the component of this horizontal component falling in the direction of the second input axis, that is to say in the direction of the coordinate axis y ° , and generates a corresponding signal T ₂ . One can see that

this signal is positive when yC is in the first or fourth quadrant, and negative when y ° is in the IL or HL quadrant flying swirl vector H of the gyro 14 to turn the shortest route in the north direction. In the II. And III. In the quadrant, a counter-clockwise rotation is required in order to bring the twist vector H to the north by the shortest possible route. If the swirl vector H falls in the north direction, the component of the horizontal component of the acceleration due to gravity in the direction of the input axis x ^{K of} the gyro disappears, and thus the signal T ₂ also disappears.

Accordingly, in the embodiment according to FIG. 5 the north direction-determining means the second torque generator 22 sitting on the second input axis x ^K and means for switching a second signal to the second torque generator 22 to initiate a rotary movement of the azimuth frame 12 via the second tap 16 and the azimuth servomotor 28, up to the first torque generator 18 switched first signal T ₂ disappears. A signal switched to the second torque generator 22 causes a deflection of the gyro about the first input axis j * and thus a signal at tap 16. This signal controls the servo motor 28 via the amplifier 32 and thus causes the Azimuth frame 12 about the azimuth axis 10 or ζ °. The second signal applied to the second torque generator 22 during the initial alignment preferably has a constant magnitude. The sign of this second signal depends on the sign of the first signal T ₂ connected to the first torque generator 18 and thus on the component of the horizontal component of the rotation of the earth in the direction of the second input axis x ^{K of} the gyro 14, such that when the first signal T _{2 is} negative and thus the component of the earth's rotation in the direction of the first input axis x ^{K is} positive, the azimuth frame 12 is rotated clockwise in plan view. When the first signal T _{2 is} positive and thus the component of the horizontal component of the earth's rotation effective in the direction of the first input axis x ^{K is negative, the azimuth frame 12 is rotated counterclockwise.} In this way it is ensured that the spin axis is aligned to the north in the shortest possible way during the initial alignment by rotating the azimuth frame 12.

Now the signal T _{2 is} also zero if the swirl vector H is not oriented to the north, but to the south switched first signal T ₂ with a fixed threshold value and means for switching a fixed signal to the second

Torque generator 22, if the first signal T _{2 is} less than this threshold value, for rotating the azimuth frame 12 by a fixed angular amount, so that the first signal T _{2 is} greater than the threshold value.

Means are then provided for checking the sign of the first signal T ₂ then obtained and means for applying the second signal with the sign dependent on the sign of this first signal T _2. This ensures that the swirl vector cannot accidentally stop in the south direction instead of entering the north direction.

In the embodiment according to FIG. 5, the azimuth frame 12 is rotated as a function of the first signal T ₂ until the twist vector H and the coordinate axis x ^{c are} in the north direction. The angle Kz between the coordinate axis j ^ and the reference direction, e.g. x ° ^ x ^F , yeasts then immediately the

■ Course angle ψ.

In addition 6 sheets of drawings

Claims (9)

Patent claims: J. Self-aligning course reference device for navigating a vehicle, in which by a The initial heading determines the north heading and then in course reference mode for navigation continuously a heading angle is tapped, containing: an azimuth frame, which is about an azimuth axis is rotatably mounted, a biaxial gyro mounted on the azimuth frame, wherein the spin axis of the gyro lies in a plane perpendicular to the azimuth axis, a first input axis of the gyro parallel to the azimuth axis and ι s the second input axis of the circular egg is perpendicular to the twist axis and the first input axis, a first and second tap on the first and second input axis of the gyro, a first and second torque generator on the first and second input axis of the gyro, respectively, whereby the second tap located on the second input axis is connected to the first torque generator, and that on the first Input axis of the gyro sits, and the initial alignment signal switched to the first torque generator is switched on at the same time to means determining the north direction, a servomotor for rotating the azimuth frame around the azimuth axis and an angular position transmitter arranged on the azimuth axis, characterized in that (a) the one on the first input axis (y *) of the The pickup (16) arranged on the gyro (14) is connected to the servomotor (28), (b) a signal can be applied to the second torque generator (22) arranged on the second input axis (x ^K ) of the gyro (14) during course reference operation, which signal reproduces the vertical component of the earth's rotation (ΩλιπΦ), and (c) the course signal for navigation during course reference operation from the azimuth angle encoder (30) taking into account the north direction determined during the initial alignment. 2. Selbstnordendes course reference device according to claim 1, characterized in that for the Initial alignment (a) an accelerometer (40) is arranged on the azimuth frame (12), the input axis of which is parallel to the spin axis (z *) of the gyro (14), and (b) on the torque generator (22) arranged on the second input axis (x *), instead of the signal reproducing the vertical component of the rotation of the earth, optional signals can be switched on which depend on the deviation of the angular position of the azimuth frame measured by the azimuth angle encoder (30) depend on specified 0 °, 90 ° or 180 ° positions, whereby in the 0 ° position the spin axis (z *) of the gyro is parallel to the vehicle's longitudinal axis (x ¹ ) , (c) as a means for determining the north direction Signal evaluation system (Fig. 3) provided is containing (ei) memories (42,44, 46) in which the signals (75), which are connected to the first torque generator (18) seated on the first input axis of the gyro (14), in the 0 ° position, the 90 ° position and 180 ° position can be saved, (c ₂ ) memories (48,50,52) in which the signals (A /) of the accelerometer (40) can be stored in the 0 ° position, the 90 ° position and the 180 ° position, and (C ₃ ) a computer circuit (54) for forming the sine and / or cosine of the initial value of the course angle from the stored signals. 3. Selbstnordendes course reference device according to claim 2, characterized in that the computer circuit (a) contains means (56,58) to form the negative Mean value of the on the first torque generator in the 0 ° position and in the Signals connected to the 180 ° position and stored in the memories (42, 46), whereby a signal representing the drift of the gyro about the second input axis (£ ») is received, (b) means (60,62) for forming the mean value of the signals of the stored in the memories in the 0 ° position and in the 180 ° position Accelerometer, which eliminates the zero point error of the accelerometer reproducing signal (Ä ») is received, (c) means (64) for subtracting the zero point error signal from the accelerometer signal stored in the 0 ° position, whereby a first corrected acceleration signal is obtained, (d) Means (66) for multiplying the first corrected acceleration signal by the ratio of the vertical component (Ω,) of the rotation of the earth (Ω _ε ) and the acceleration of gravity (g) to form the product of the initial value of the pitch angle # (0) and the said vertical component (Q ₁ ) the rotation of the earth, (e) Means (68) for adding the stored signal applied to the first torque generator in the 90 ° position and the drift signal (£ ») and for subtracting the product of the pitch angle [# (0)] and the vertical component (ß _s ) the rotation of the earth, whereby a first sum signal is generated, and (f) Means (70) for dividing the first sum signal by the horizontal component (β _c ) of the earth's rotation, whereby a signal [cos "ψ (0)] representing the cosine of the initial value of the heading angle is obtained. 4. Selbstnordendes course reference device according to claim 3, characterized in that the computing circuit continues (g) contains means (72) for subtracting the zero point error signal [B _x ) from the signal of the accelerometer (40) stored in the 90 ° position, whereby a second corrected acceleration signal is obtained, (h) Means (74) for multiplying the second corrected acceleration signal by the ratio of the vertical component (Q ₅ ) of the rotation of the earth and the acceleration due to gravity (g) to form the product of the initial value of the roll angle [<p (0)] and the improved vertical component ( Qs) the rotation of the earth, (i) Means (76) for adding the stored signal applied to the first torque generator in the 0 ° position, the drift signal (B _x ) and for subtracting the product of the initial value of the roll angle [g> (0)] and Vertical component (Q _s ) of the earth's rotation, which generates a second sum signal, and (j) Means (73) for dividing the second sum signal by the horizontal component (β _c ) of the earth's rotation, whereby a first signal [sin v (O) | o] representing the sine of the initial value of the course angle is obtained. 5. Selbstnordendes course reference device according to claim 4, characterized in that the computing circuit Farther (k) Means (80) contains for adding the stored signal applied to the first torque generator (18) in the 180 ° position, the drift signal (B _x ) and the product of the initial value of the roll angle [ψ (0)] and vertical component (ß _s ) of the earth's rotation, whereby a third sum singal is generated, (1) Means (82) for dividing the second sum signal by the negative horizontal component (-ß _c ) of the earth's rotation, whereby a second signal [sin ψ (Ο) | ΐ8ο) is obtained which represents the sine of the initial value of the course angle, and (m) means (84,86) for averaging the first and second, the sine of the Initial value of the signal representing the heading angle. 6. Selbstnordendes course reference device according to one of claims 2 to 5, characterized in that (A) the azimuth angle encoder (30) is a resolver, which one to the sine and one to the cosine of the Angle of rotation provides an analog output signal, (b) an analog-to-digital converter (88) is provided which receives the output signals from the resolver digitized, and (c) Angle addition means (90,92) are provided to which the digitized output signals of the resolver and the sine and cosine of the initial value of the heading angle stored in registers (94, 96) are fed and which output signals [sin φ (/ ι7), cos tp (nT)] , which represent the current course angle. 7. Selbstnordendes course reference device according to claim 1, characterized in that the north direction-determining middle (a) the one on the second input axis (x *) seated second torque generator (22) included and (b) Means for switching a second signal to the second torque generator (22) to initiate a rotary movement of the azimuth frame (12) via the second tap (16) and the servomotor (28) until the first one connected to the first torque generator (18) Signal (T ₂ ) disappears 8. Selbstnordendes course reference device according to claim 7, characterized in that (a) the one connected to the second torque generator (22) in the initial alignment second signal has a constant amount and (b) the sign of this second signal from the sign of the on the first torque generator (18) switched first signal (7J) ίο depends, such that when the first signal (T ₂ ) is negative, the azimuth frame (12) in plan view is rotated clockwise, and if the first signal (7}) is positive, the azimuth frame (12) is turned counterclockwise 9. Self-aligning course reference device according to claim 8, characterized in that the north-determining middle (Yes) Contain comparator means for comparing the first signal (T ₂ ) switched to the first torque generator (18) with a fixed threshold value as well (b) Means for applying a fixed signal to the second torque generator (22), if the first signa! is smaller than this threshold to rotate the azimuth frame (12) a fixed angular amount such that the first signal is greater than the threshold value, (c) means for checking the sign of the first signal (7J) and then obtained (d) Means for applying the second signal with the sign of this first signal dependent sign.