DE3050615C2 - Device for determining the north direction - Google Patents

Description

a self-northing short-position reierenzgerät known, in which the north direction is also determined by an initial alignment and then in course reference mode a course angle is continuously tapped for navigation. The well-known course reference device contains an azimuth frame which is mounted rotatably about an azimuth axis. On the azimuth frame is a biaxial one Arranged gyro, the spin axis of the gyro in a plane perpendicular to the azimuth axis lies, a first input axis of the gyro parallel to the azimuth axis and the second input axis of the gyro runs perpendicular to the twist axis and the first input axis. On the first or second input axis of the There is a first and a second tap each at the top. Furthermore, sit on the first and second input axis of the Gyro a first and a second torque generator. The second one arranged on the second input axis The tap is connected to the first torque generator, which is located on the first input axis of the gyro. The initial alignment signal switched to the first torque generator is on at the same time Means determining north direction switched on. The azimuth frame is around the azimuth axis by a servomotor rotatable. Furthermore, an angular position sensor is arranged on the azimuth axis.

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 around the Vehicle longitudinal axis pivotably mounted. The two-axis gyro is a two-axis turning gyro. It is not only the second tap is switched to the first torque generator but similar to the DE-OS 27 41 274, also the first tap located on the first input axis to the one on the second input axis of the gyro seated second torque generator. Finally still sits on the azimuth frame an accelerometer whose input axis is parallel to the spin axis of the gyroscope.

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 going vertical plane. 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 with respect to the roll frame 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 ^c position offset by 90 °.

In the first "northing" mode, the computer delivers from the two positions of the azimuth frame measured and stored, reproducing the rotational speed around the second input axis Signals from the rate gyro and the acceleration signals also measured and stored in these positions of the accelerometer the initial deviation of a through the vehicle longitudinal axis vertical plane going 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 If the computer ran the angular velocity signals from the rate gyro the true course of the Vehicle reproducing signal.

In this known arrangement, as in DE-OS 27 41 274, both the north direction in the initial alignment and the course angle in the "course-position reference" mode of operation are calculated by a computer from the two signals of the two-axis rate gyro and accelerometer signals. The computer contains means for storing the signals from the rate gyro in the ("position and the 90 ° position as well as means for correcting the stored signals by means of plumb sensors, means for dividing the signals in the (!" Position and the 90 ° position) Position stored, corrected signals by the horizontal component Q _1. = Ω _ε cos Φ of the earth's rotation speed and means for forming the sine and cosine of the true azimuth angle from the signals obtained in this way.

The advantage of the arrangement according to DE-OS 29 22 412 is that with a favorable mechanical effort a considerable simplification of the signal processing compared to the arrangement according to DE-OS 27 41 274 is achieved.

The scale factor goes into the signals for the sine or cosine of the true azimuth angle obtained in this way of the rate gyro and thus also the scale factor error a. This scale factor error would have to be determined in order to achieve maximum northing accuracy and are taken into account arithmetically.

The invention is based on the object of determining the azimuth angle with a device of the type defined at the outset to determine a catfish independent of the scale factor error.

According to the invention this object is achieved in that

(A) the azimuth frame in a further switching state of the control device by the servomotor in a 270 ° position can be rotated,

(b) the signal processing means for determining the north direction continue

(b,) contain means for storing the signals stored in the 270 ° position,

Ib ₂ ) Means for forming half the difference between the signals stored at the 90 ° position and the 270 ° position,

(b ₃ ) middle! to divide the resulting signal by the horizontal component ß _r = Ω _ε cos Φ of the earth's rotation to form the cosine of the azimuth angle,

Ib ₄ ) Means for determining the quadrant of the azimuth angle to the north from the values of the negative sine and cosine of this angle obtained through the divisions without precise knowledge of a scale factor error,

(b ₅ ) Means to be independent of the scale factor

Determination of the absolute value of an angle function of the azimuth angle to the north the differences between the in the O ° position and the

180 ° position or the one in the 90 ° position and the signals stored in the 270 ° position,

(b ₆ ) Means for determining an associated win-

kelwerts less than 90 ° from the absolute value of the angle function and

(b ₇ ) Means for determining the azimuth angle to the north from said angle value and the quadrant determined from sine and cosine.

Refinements of the invention are the subject of the subclaims.

7 8

One embodiment of the invention is the next position in which the centrifugal spin axis z ^{K is} parallel to

With reference to the associated drawings, an axis x ^G is fixed to the device, in a 90 ° position, in

gen explained in more detail: a 180 ° position or rotatable into a 270 ° position

1 is a schematic perspective illustration.

development of a device for determining the north direction 5 In the embodiment according to Flg. 1 is preceded

tion. sets that the azimuth frame 10 with the azimuth axis z ^c

Fig. 2 shows the means for a rough determination of which is precisely vertically aligned for the pre-alignment

Trigonometric functions of the azimuth angle to the north. or at least the deviations from the vertical

Fig. 3 shows the determination of the exact value of the negligible.

Azimuth angle as well as the determination of the course angle. 10 The signal processing means contain similar to

Fig. 4 gives an overview of the sequence of the nor- in the arrangement according to DE-OS 29 22 412 means 44, 46,

application process. '48 for storing the first torque generator

Fig. 5 is a modification of the means for the rough 16 supplied signals -T ₂ 1 _o , -T ₂ 1 «, and T ₂ 1 ₁₈₀ in the

Determination of the angle functions and shows the O ° position, the 90 ° position or the 180 ° position. the

inspection of the incorrect mounting bracket of the gyro. 15 signal processing means also contain means 50,

Fig. 6 is a modification of the means for determining 52 for forming half the difference between the

Calculation of the exact value of the azimuth angle and shows the values and signals stored in the 180 ° position,

the consideration of the incorrect mounting angle of the circular and means 54 for dividing the signal obtained thereby

sels. by the horizontal component Ω _Γ = Ω _Ε cos Φ of the earth

The self-aligning course-attitude reference device of 20 turning speed.

Fig. 1 contains an azimuth frame 10, which is around an AzI The signal processing means for determining the

mutaxis z ^c is rotatable. The azimuth frame defines north direction in addition to the memory for

a coordinate system with the coordinate axes x * ⁷ . Storage of the first torque generator 16 in

y ^c and z ^c . On the azimuth frame 10 is a gyro 12 of the 0 ° position, the 90 ° position and the 180 ° position

arranged, whose twist H parallel to the axis x ^c ver 2s supplied signals furthermore a memory 114 for

runs. The gyro defines a coordinate system with storage of the first torque generator 16 in

the twist axis z ^K , one of the signals supplied to the azimuth axis z ^c parallel to the 270 ° position. Also included

first input axis y ^K and a second input the signal processing means for determining the

axis **, which is perpendicular to the twist axis z ^K and the first north direction continues to means 116, 118 for forming the

Input axis y ^K runs. The azimuth frame 10 with 30 half the difference between the 90 ° position and the 270 ° -

its coordinate system χ °, y ^c and z ^c is stored around the AzI position in the memories 46 and 114, respectively

Mutachse z ^c rotatable with respect to a housing-mounted signals.

Coordinate system x °, y ^G and z ^c , where the coordinate- The division of half the difference of the In the O ° position-

according to z ^{G is} parallel to the coordinate axis z ^c and signals stored in ment and in the 180 ° position

the illustrated (»" position the coordinate axes x ^G 35 through the horizontal component of the earth's rotational speed

and y ^G parallel to the coordinate axes x ^c and y ^{c of} the digkelt provides a signal which is the negative sine

Azimuth frame 10 are. The angle of rotation of the azimuth angle represents the azimuth angle - sin ψ ,

frame 10 about the azimuth axis z ^c from the illustrated In an analogous manner are in the execution according to

The 0 ° position is denoted by X _1. Preferably, Fig. 2 is means 120 for dividing half the difference of the

the housing-fixed coordinate system parallel to a 40 _in d _s memories 46, 114 stored signals by the

vehicle-fixed coordinate system with the coordinate-horizontal component ß _f = ß _f cos Φ of the earth's rotation

outward vehicle longitudinal axis x ^r , vehicle transverse axis y ^F provided. This division gives a value for the

and vehicle ^vertical axis z F arranged. negative cosine of the azimuth angle - cos ψ.

The values thus obtained for - sin ψ and - cos ψ are located on the first input axis y ^{K of} the gyroscope 12 and result in a first tap 14 and a first torque generator «(, without precise knowledge of the scale factor error. 16. On the second input axis x ^K des Gyroscope 12 sit- They can be affected by a scale factor error with a zen, a second tap 18 and a second torque inaccuracy. However, these allow the generators 20. The on the first input axis y ^{K is located} - Determination of the quadrant in which the azimuth-ordered first Tap 14 is located at angle to north via an amplifier 22. Means are accordingly connected to the second torque generator 20, which is located at 5 ° for determining the quadrant of the azimuth angle of the second input axis x ^{K of} the gyro 12. The north from the through the divisions at 54 and 120 on the second input axis x ^K , the second tap 18 obtained without precise knowledge of a scale factor error is over an amplifier 24 connected to the first nen values of the negative sine and cosine of this torque generator 16, which is provided on the first angle.

Input axis >> * of the gyro 12 is seated. In this way ⁵⁵ There are still means of

is the gyro about its input axes electrically dependent on the determination of the absolute value of an angular

seln housing tied up. It is a two-function of the azimuth angle to the north,

axial rate gyro. The torque generator means are illustrated in Figure 3 and are described below

16 supplied signal T1 is tapped via a filter 26 described in detail. There are still funds for

fen and, in a manner to be described below, the signal ^{curve ω} determination of an associated angle value smaller than

processing means supplied. 90 ° from the absolute value of the angle function and mean

A servomotor 30 is seated on the azimuth axis z ^c to determine the azimuth angle to the north from the

Rotation of the azimuth frame 10 about the azimuth axis said angular value and that of the sine and cosine

z ^c . On the azimuth axis ζ ° an angular position-specific quadrant is also provided,

Lungsgeber 32 arranged. A switchable control input ⁶⁵ The embodiment described is based on the

direction 34 is based on the signal of the angle position recognition that it is possible on the one hand to use the

bers 32 is applied and controls the servomotor in such a way that angular radio frequency influenced by a scale factor error

the azimuth frame 10 optionally in the shown 0 ° - positions of the azimuth angle its quadrant to be determined-

len, and that on the other hand it is possible to be one of a Scale factor error to form unaffected angle function of the azimuth angle, which, however, in relation to is ambiguous on the azimuth angle itself. From the quadrant determined aul the one way and the on the other way determined angle function, z. B. the absolute value of the sine, then the actual The value of the azimuth angle can be determined. Accordingly, they contain signal processing

quadrant

II

III

IV

Azimuth angle

^ = 180 ° -I v / 1

v = 180 ° + l vl

ν = 360 ° -I ψ |
The aforementioned means for determining (1 + DSF,) are, as in Flg. 3, of means 148 for dividing said root of the sum of squares by the double horizontal component 2 Ω,. the earth

means also means means for determining the Azlmutwln- io rotation, which deliver a current value for kels to north from said angle value and the (1 + DSF _x ) at output 126 . This current value is applied to the means 122 and 124 for multiplication.

The arrangement described allows an accurate

nerically to be taken into account, a further condition of the arrangement described so far is that the incorrect mounting angle α of the gyro 12 by the azimuth

quadrants determined from sine and cosine.

In detail, this embodiment is as follows built up:

As from Flg. 2 As can be seen, means 122 and 124 are 15 measurements that are not impaired by scale factor errors . So there is no need for any scale factor errors arithmetically (1 + DSF _x ) before dividing by the horizontal component Ω _{ο of} the earth's rotation, where DSF _{x is} an assumed scale factor error. For the first
Calculation process can, for example, _{assume DSF x} = O 20 assumed axis z ^{c is made} negligibly small. If will, or you can use an estimated or approximate- this is not possible or an undesirably high approximately known value. The arrangement represents effort, the incorrect mounting angle according to FIG. 3 contains, in addition to the means for determining FIGS (1 + DSF _x ) from the 25 has been saved. This is possible because the incorrect assembly of the signals stored in the memories 44, 48, 46, 114 practically does not change in the course of the tent, which will be described in more detail below. A signal Flg. 5 corresponds essentially to the arrangement of

(1 + DSF _x ) appears at an output 126. Mit- Fig. 2 and Fig. 6 essentially correspond to tel 128, 130 provided for inputting the arrangement of Fig. 3 thus determined, and corresponding parts are new values for (1 + DSF _x ) in said means 122 30 are each provided with the same reference numerals,
or 124 for multiplication. According to Fig. 5, half the difference in the 0 ° -

The means for determining the absolute value of a position and in the 180 ° position. In the memories 44, the angle functions of the azimuth angle are shown in FIG. 3 and 48 stored signals are multiplied by one. They contain means 132 for forming the difference between the incorrect mounting angle of the gyro 12 around the azimuth of the signals stored in the 0 ° position and in the 180 ° position in the factor a ^ which is reproduced by the axis z ^c as by the block stores 44 and 48, respectively , Means 134 150 and the summing point 152 shown, half of it for squaring this difference means 136 for forming the difference between the 90 ° position and the 270 ° position difference between the 90 ° position and the 270 ° - ' signals stored in the memories 46 and 114 position in the memories 46 and 114 stored in the opposite direction. Likewise, half the difference between the In signals, means 138 for squaring this difference and 40 of the 90 ° position and In the 270 ° position is in the storage means 140 for adding the squares obtained in this way. There are 46 and 114 stored signals multiplied by means 142 for extracting the root of the obtained the incorrect mounting angle of the gyro 12 by the sum of the square and means 144 for forming the azimuth axis z ^c reproducing factor a ", as by the quotient of the means 132 is shown the first block 154 and the summing point 156 , ren difference and the square root of the sum of squares, 45 of half the difference in the 0 ° position and in which the absolute value of the sine of the azimuth 180 ° position In the memories 144, 148 stored

Signals switched in the opposite direction.

Similarly, in Flg. 6, when determining the absolute value of the angular function of the azimuth angle, the difference formed at 136 between the signals stored in the 90 ° position and in the 270 ° position in the memories 46 and 114 multiplied by the incorrect mounting angle of the gyro 12 about the azimuth axis z ^c reproducing factor a ^ as indicated by the block 158 and summing point 160, the difference formed at 132 of the signals stored in the 0 ° position and in the 180 ° position in the memories 44 and 48 is switched. The difference formed at 132 between the signals stored in the 0 ° position and in the 180 ° position in the memories 44 and 48 is multiplied by the factor Ot _x ^ which reproduces the misalignment angle of the gyro 12 about the azimuth axis z ^c as indicated by the block 162 and summing point 164 is indicated, the difference in the 90 ° position and in the 270 ° position in the

With the quadrant determined in this way and the signals stored in accordance with 65 memories 46 and 114 respectively, counter-F i g. 3 obtained value of | vl results in the actual switch.

before angle ν unaffected by scale factor errors according to ρ ig. 4 clearly shows the sequence of the northing

'following relationship operation.

kels to north I sin ψ | signal representing is obtained. The means for determining the associated angular value are formed by means 146 for generating the arcsine function.

The quadrant determining means place the quadrant of the azimuth angle according to the following relation fixed:

quadrant

I. sin ψ ; cos; II sin ψ ; cos < III sin φ < cos < IV sin ψ < cos; > 0 > 0 > 0 cO CO cO CO > 0

In addition 6 sheets of drawings

Claims (9)

Patent claims: ίο Ι. Device for determining the north direction, containing an azimuth frame which is mounted so as to be rotatable about an azimuth axis,
a rate gyro which is responsive to components of the earth's rotational speed and provides corresponding signals and which is arranged on the azimuth frame, wherein the spin axis of the rate gyro lies in a plane perpendicular to the azimuth axis and
an input axis of the rate gyro runs in this plane perpendicular to the spin axis, a servomotor for rotating the azimuth frame around the azimuth axis, a control device through which the servomotor can be turned into a first position (0 ° - Sielluiig) and a second offset by 90 ° Position (9O ° position) as well as one opposite the 0 ° - Third position offset by 180 ° is controllable, Signal processing means for determining the north direction to which the rate gyro signals are activated and which ones Contains means for storing the signals of the rate gyro in the 0 ° position, the 90 ° position and the 180 ° position, Means for forming half the difference in the jo O ° position and stored in the l90 ° position Signals, Means for dividing half the difference by the horizontal _{component ß r} = ß _£ cos Φ of the earth's rotation speed to generate a signal representing the sine of the true azimuth angle, Means for generating a signal representing the cosine of the true azimuth angle and
a quadrant logic to which the signals representing the sine and cosine are fed to determine the quadrant of the true azimuth angle, characterized in that (a) the azimuth frame in a further switching state of the control device by the servomotor can be rotated into a 27O ° position, (b) the signal processing means for determining the north direction continue (b,) contain means for storing the signals stored in the 270 ° position, (b ₂ ) Means for forming half the difference between the signals stored at the 90 ° position and the 270 ° position, (b ₃ ) means for dividing the signal obtained thereby by the horizontal component ß _r = ß _E cos Φ of the earth's rotation to form the cosine of the azimuth angle, (b ₄ ) Means for determining the quadrant of the azimuth angle to the north from the values of the negative sine and cosine of this angle obtained through the divisions without precise knowledge of a scale factor error, (b ₅ ) Means for determining the absolute value of an angle function of the azimuth angle to north from the differences between the "" position and the 180 ° position or that in the 90 ° position and the 270 ° position, independently of the scale factor Position of stored signals, (b ₆ ) Means for determining an associated angle value smaller than 90 ° from the absolute value of the angle function and (b ₇ ) Means for determining the azimuth angle to the north from said angle value and the quadrant determined from sine and cosine. 2. Apparatus according to claim 1, characterized by means for multiplying said half differences by (1 + DSF _x ) before dividing by the horizontal component of the earth's rotation, DSF _{x being} an assumed scale factor error. 3. Apparatus according to claim 2, characterized by (a) Means for determining (1 + DSF _x ) from the stored signals and (b) Means for entering the new value determined in this way for (1 + DSF _x ) in the said center! for multiplication. 4. Device according to one of claims 1 to 3, characterized in that the quadrant-determining means define the quadrant of the azimuth angle Ψ according to the following relationship quadrant sin ψ> 0 II sin ψ> 0 III sin ψ <0 IV sin ψ <0 cos ψ> 0
cos V <0
cos ψ <0
cos ψ > 0 5. Device according to one of claims 1 to 4, characterized in that the means for determining the absolute value of an angle function (a) Contains means for taking the difference in In the O ° position and stored in the 180 ° position Signals, (b) means of squaring this difference, (c) Means for forming the difference between those stored in the 90 ° position and in the 270 ° position Signals, (d) means for squaring this difference, (e) Means for adding the squares thus obtained, (0 means for pulling the wort! the obtained Sum of squares and (g) Means for forming the quotient of the former difference and the square root of the sum of squares, whereby a signal representing the absolute value of the sine of the azimuth angle to north sin ψ is obtained. 6. Apparatus according to claim 5, characterized in that the means for determining the associated angular value of means for generating the Arcusslnuslunktlon are formed. 7. Apparatus according to claim 3 and 5, characterized in that said means for determining (1 + DSF,) means for dividing said Roots are formed by the double horizontal component of the earth's rotation. 8. Device according to one of claims 1 to 7, characterized in that (a) half the difference of in the O ° position and stored in the 180 ° position signals multiplied by the incorrect installation angle of the gyro about the azimuth axis z ^c reproducing factor a ^ to half the difference in the 90 ° - position and the signals stored in the 270 ° position are opposed to and (b) half the difference between the signals stored in the 90 ° position and in the 270 ° position multiplied by the factor a _v of half the difference ^{between the 0 ° position and the incorrect mounting angle of the gyro about the azimuth axis z c} and signals stored in the 180 ° position are connected in the opposite direction. 9. Device according to claims 5 and 8, characterized in that in the determination of the Absolute value of the angular function of the azimuth angle (a) the difference between the signals stored in the 90 ° position and in the 270 ° position multiplied by one of the incorrect mounting angles! of the gyro about the azimuth axis reproducing factor ü _{ly of} the difference between the signals stored in the 0 ° position and in the 180 ° position is switched and (b) the difference between the signals stored in the 0 ° position and in the 180 ° position multiplied by the factor a _{xv representing} the incorrect mounting angle of the gyro about the azimuth axis of the difference between the 90 ° position and the 270 ° - Position stored signals is switched in the opposite direction. The invention relates to a device for determining the north direction containing an azimuth frame which is mounted rotatably about an azimuth axis, a rate gyro which responds to components of the earth's rotational speed and delivers corresponding signals, which is arranged on the azimuth frame, the spin axis of the rate gyro in one to the azimuth axis vertical plane and an input axis of the rate gyro runs perpendicular to the spin axis in this plane, a servomotor for rotating the azimuth frame around the azimuth axis, a control device through which the servomotor for optional turning in a first position (0 ° position) and a on the other hand, a second position offset by 90 ° ^ "- position) and a third position offset by 180 ° compared to the O ° position is controllable, signal processing means for determining the north direction, to which the signals of the rate gyro are switched and which contain means for storage the Si signals of the rate gyro in the 0 ° position, the 90 ° position and the 180 ° position, means for forming half the difference between the signals stored in the 0 ° position and in the 190 ° position, means for dividing half the difference by the horizontal component Q _c = ß _E cos Φ of the earth's rotation speed for generating a signal representing the sine of the true azimuth angle, means for generating a signal representing the cosine of the true azimuth angle and a quadrant logic to which the signals representing the sine and cosine are fed to Determination of the quadrant of the true azimuth angle.
It is a device for navigating land vehicles ι »known (DE-OS 25 45 025), in which the angle between the gyroscopic axis and the north direction is determined by means of a tape-suspended meridian gyro, the directional moment of which is compensated by a counter-moment. A free gyro, which serves as a course reference device for navigating the vehicle, is aligned with the north direction determined in this way. Such a self-aligning course reference device works with two steps: Before starting the journey, the north direction is determined. The course reference device is initially aligned in this north direction. The course reference device then continuously supplies the course of the vehicle in relation to this north direction in course reference mode.
From DE-OS 27 41 274 it is known to determine the north direction with the help of a biaxial rate gyro *: instead of by means of a tape-suspended gyro with a horizontal twist axis, the twist axis of which is arranged vertically. The rate gyro contains one on each of two horizontal input axes that are perpendicular to one another k> tap and one torque generator each. The output signals the taps are each crossed over an amplifier on the other input axis seated torque generator switched. The signals switched to the torque generator correspond to the components of the horizontal component of the earth's rotation. From the relationship between the two Signals results in the initial value of the course angle. In order to get this initial value correctly, if the gyroscopic spin axis, which extends in the direction of the vertical axis of the vehicle, is not exactly vertical to the Two accelerometers are provided which provide the vehicle's lean angle. From the signals from the accelerometer and from the two torque generators on the rate gyro connected signals, the initial value of a fixed-earth coordinate system is used in a computer related course angle determined. In the arrangement according to DE-OS 27 41 274, the same two-axis rate gyro is after the pivoting used by 90 ° with an essentially horizontal gyroscopic spin axis as a course-attitude reference device, whereby the computer from the angular velocities and the signals of the accelerometer taking into account the direction determined during the initial alignment Slow values constantly the position of the vehicle and in particular continuously calculates the true course angle. In both cases, the heading angle and the vehicle speed measured in the vehicle's longitudinal axis are used the position of the vehicle in a geographical area or grid coordinate system determined. The known arrangements described provide the vehicle position with high accuracy. However, they are too expensive for many applications, while on the other hand there are applications in which the requirements for the accuracy of the navigation are lower, but a less complex course reference device is required.
By the unpublished DE-OS 29 22 412 lsi