Patent Application
20090076729
The technical solution provided can be used for navigational, piloting and other purposes.
True meridian is considered to be the arc of a great circle of the points of the surface of the heavenly body, the Earth in particular, equal to the geographical longitude. In the horizontal plane true meridian in navigation is considered to be the tangent to said arc. In the present application, under true meridian the said tangent is meant as well.
For determining true meridian use is made of different methods: magnetic, astronomic, and gyroscopic.
The main remarkable drawbacks of the magnetic method are as follows:
This method is implemented by the astrocompasses.
The main remarkable drawbacks of the gyroscopic method are as follows:
An object of the present technical solution is to provide quick and accurate determination of true meridian not only with unmovable object but also with its moving irrespective of the disturbing factors influence, in particular, weather conditions, vibrations, transverse accelerations, external magnetic fields, without the necessity of knowing the location and without the necessity of using gyroscopes.
For achieving said goal there is a method provided based on fixing of the linear velocity vector V caused by the heavenly body rotation, particularly, of the terrestrial globe. This vector is said to be perpendicular to true meridian. Thus, knowing the direction of said vector means knowing true meridian as well.
Said fixing is implemented by the linear acceleration equal to zero. Said linear acceleration is produced by the change (with rotating) of the vector V projection on the sensitivity axis ξ of the device of the horizontal acceleration [1]. Said axis is considered to be always horizontal and be located in the plane of determining pressure (the plane containing the points of determining pressure).
Said points are said to be located symmetrically relative to the vertical and are inducedly rotating around it.
Equality of said linear acceleration to zero is determined by zero pressure difference in said points.
Said points are said to be located similarly in similar inner cavities of the vessels (the inner cavities whereof being filled with flowing medium) similarly on the parallel straight lines.
Upper and lower points of the contours of said inner cavities of said vessels are said to remain as such (upper and lower), irrespective of permissible tilting. Using said points of determining pressure, upper and lower points, similarity of said inner cavities of said vessels and using differential scheme to be implemented in the device of the horizontal acceleration [1] is considered to avoid any harmful influence of the transverse accelerations: vertical (tilting as well) and transverse as well as vibrations, temperature changes and others.
In the technical solution proposed said vessels are fastened on the axle (shaft) of an electric motor (called as a device), the axle (shaft) whereof being located along the vertical or along the vertical axis of said movable object, in case its body is used as a horizontal platform [2].
With it, said parallel straight lines are said to be parallel to said axle (shaft) of said device electric motor, thus, the vertical as well.
Pressure signals in said points are supplied to said differential scheme of said device of horizontal acceleration from the output thereof there is a signal taken of said linear acceleration.
With rotating of a rotor of said device electric motor together therewith rotation is performed of the plane of determining pressure (the plane containing the points of determining pressure) and the axis of sensitivity ξ of the device of horizontal acceleration. Said axis is considered to be always horizontal.
When said axis ξ (as well the plane of determining pressure, wherein said axis is located) is superposed with rotating with said vector V (being perpendicular to true meridian), the projection of said vector on said axis ξ is said to be maximum and equal to the velocity v.
When said axis ξ with rotating, will turn out to be perpendicular to said vector V, i.e. directed along true meridian, the projection of said vector on said axis ξ is said to be equal to zero.
Changing said projection of said vector V means that with rotating said vessels of said device of horizontal acceleration there occurs linear acceleration, the latter changing from 0 to maximum. Mentioned change occurs periodically (the period being 360°). Herewith, when said axis of sensitivity ξ with rotating is superposed with said vector V linear acceleration α, being derivative {dot over (v)}, is equal to zero ({dot over (v)}=α=0), and, when being superposed with true meridian this acceleration is maximum.
Therefore, through fixing zero signal of said linear acceleration determination is made of the direction of said vector V, thus, true meridian being perpendicular to said vector is determined as well. With such fixing true meridian is directed along the perpendicular to the plane of determining pressure and said axis ξ. For fixing true meridian relative to some line of the movable object in its initial position (before starting rotation by said device electric motor) there is said plane of determining pressure superposed with said line (so is said said axis of sensitivity ξ).
Further for more convenience and certainty, (distinctness) deviation of said plane of determining pressure (so is said axis of sensitivity ξ) will be determined relative to longitudinal axis of said movable object.
Output signal of said device of horizontal acceleration taken from its differential scheme (said signal is the difference of pressures by itself in the points of determining pressure) does not depend on disturbance factors, particularly, on transverse accelerations (vertical and, thus, it doesn't depend on permissible tilting, and transverse), vibrations and temperature changes [1]. Moreover, said signal is not considered to depend on centripetal (centrifugal) accelerations occurring with rotating around each of three mutually perpendicular axes, since said points are located symmetrically relative to the vertical and similarly on said parallel straight lines, they being parallel to said vertical and contained in similar inner cavities of said vessels.
If determination of true meridian of the unmovable object is required, then there is no any necessity in continuous rotation of said rotor of said device electric motor together with the vessels of said device of horizontal acceleration. Herewith, it is enough to cease this rotation, when said plane of determining pressure (so is said axis of sensitivity ξ) is superposed with said vector V.
For that, use is made of a control circuit called discreet. Said scheme is said to include [3] a switch-on/off button (a switch) with a spring, an electromagnet and a relay. With pushing said button said rotor of said device electric motor starts rotating. Herewith, in conformity with the above said, there occurs changeable acceleration acting in said plane of determining pressure. Because of the above, said pressure in one point of determining pressure is considered to be increasing, and in another point of determining pressure, it is considered to be either decreasing or not to be changing, accordingly. Therefore, at the output of said differential scheme (at the output of said device of horizontal acceleration) there occurs a signal which is supplied to said control circuit, particularly, to said relay. Said relay snaps into action (works), its contacts close and it is through them that power is supplied to said electromagnet called device. Said device electromagnet is said to hold said switch-on/off button in the on-position until said relay becomes deenergized, which will cause contact breaking thereof. Said electromagnet will be made dead and said switch button under the influence of its spring is expected to return to its initial position. Herewith, the electric circuit of said device electric motor will be deenergized and its rotor will stop. For accelerating this said stopping it is desirable to provide said electric motor with some brake. With such stop, said plane of determining pressure will turn out to be superposed with said vector V, the latter being perpendicular to true meridian. It is with said vector that said axis of sensitivity ξ of said device of horizontal acceleration will turn out to be superposed, said axis being always horizontal within permissible tilting. (This axis is rotating together with said plane of determining pressure).
Herewith, if said axis of sensitivity is directed to the east from true meridian, then while crossing the line of superposition of said axis ξ with the direction of said vector V the sign of linear acceleration v=α is expected to change from “+” to “−”.(α>0 changes with said crossing to α<0). And vice versa, if with mentioned induced rotating said axis ξ is directed to the west from true meridian; then while crossing the line of superposition of said axis ξ with the direction opposite to the direction of said vector V the sign α changes from “−” to “+” (α<0 changes with said crossing to α>0). This opposite sequence of changing signs of acceleration enables one to have opportunity by means of a special discriminator to automatically eliminate possible error 180° in determining the east-west direction, and thus, the north-south direction as well. Moreover, in practice, without said discriminator such kind of error is expected to be eliminated by means of different known properties [3].
The device described enables it to determine automatically true meridian only in two cases: with unmovable position of the movable object or with moving along the parallel (with strict movement towards the east or west.
In general case, (with any other direction of movement) the plane of determining pressure as well as said axis of sensitivity ξ are set in the device described in conformity with the direction of the resulting vector, it being itself a vector sum of the two vectors: said vector V and ground speed vector W (the speed relative to a heavenly body, the Earth, in particular).
The error occurring herewith (an angle between said vectors) can be considerable enough (within 360°). It should be noted that the error mentioned might be also using a gyrocompass. For its determining it is required to know the speed of sea craft movement and geographical latitude of its location.
The present application has for its purpose to automatically eliminate said error. Herewith, the solution of the problem of automatically determining true meridian while moving a movable object at any speed without any necessity of knowing the latter and without any necessity of knowing its location is eliminated.
Herewith, true meridian is determined by perpendicular to the vector of linear velocity V to be produced by rotating a heavenly body, the terrestrial globe, in particular.
For achieving the above, elimination is made of any harmful influence of the projection of said vector W by means of induced influence in the plane of determining pressure on the points of determining pressure (pressure sensors), being opposite relative to the sign and equal relation to the value of the influence to be produced by changing vector W projection on said plane.
Such opposite and equal influence is expected to be implemented by means of artificially created magnetic field, magnetic induction thereof is considered to be perpendicular in the horizontal plane to said vector W, and its value is determined by the value of the velocity w of the vector W.
For achieving this purpose, the device described previously is added by the electromagnet (called road) the winding thereof is fed by the signal (in the form of electric voltage) of the ground speed w. The core of said electromagnet is considered to be perpendicular in the horizontal plane to the direction of the vector W and is located on the horizontal platform called road. Herewith, said core is located symmetrically relative to the points of determining pressure (at similar distances from each of sad points).
The information regarding of the ground velocity vector W can be obtained from the inertial navigation system (INS) or from the Doppler system.
It should be stressed that the authors managed to find the solution (by means of the two different methods) of determining vector W in a way of free running, without any kind of radiation (unlike the Doppler system), which makes such kind of solutions be absolutely disturbance-protected from an induced external disturbances and without using gyroscopes (unlike the INS). Herewith, the solutions mentioned are said to be independent on any disturbance factors, in particular, transverse accelerations, vertical and centripetal (centrifugal) including, vibrations, temperature changes and others. The authors expect these solutions to be patented in the USA should there be the permit of the Patents Department of Israel.
The information regarding the vector W includes the value (module) of this velocity w and the direction of said vector relative to some line of the movable object, in particular, relative to its longitudinal axis.
The angle between said axis and said vector W (its direction) is designated through ε.
The more the value w, the more the core of said electromagnet is magnetized.
In the device implementing the method proposed an electric motor is also introduced called road. Its axle (shaft) is located along the vertical or along the vertical axis of the movable object, in case if the body of said object is used as the horizontal platform.[2].
For achieving the above the body of the device provided is fastened on the horizontal platform or in the case mentioned, on the body of said movable object.
Said axle (shaft) of said road electric motor id firmly connected to said road platform.
Said road electric motor, receiving said signal of an angle ε, is expected to turn said road platform, including said road electromagnet, and fixed said road line thereon by said angle.
In the initial position said road line is located along, particularly, longitudinal axis of said movable object (or along the line parallel thereto). Therefore, said road line means the direction of said vector W.
Thus, for corresponding influence of the magnetic field of said road electromagnet on the sensitive elements of the pressure sensors there are the following measures provided:
Due to the above measures with rotating said rotor of said device electric motor the influence (on the points of determining pressure) of the changeable projection of the magnetic induction on the plane of determining pressure is said to be the same as the influence of the changeable projection of said vector W on the same plane, but of the opposite sign. Therefore, any harmful influence of said vector W on the determination of true meridian is eliminated.
The device with the discreet control circuit considered above does not allow it to determine true meridian continuously (but just discreetly, at times).
For continuous determining true meridian rotating said rotor of said device electric motor is said to take place uninterruptedly.
Herewith, at the output of said device of horizontal acceleration ( at the output of its differential scheme 9) said signal is by itself a periodic curve (with period of 360°) of the dependence of said linear acceleration α on the angle of rotation of said axis of sensitivity ξ relative to said longitudinal axis of the movable object.
The direction of said vector V (said east west-direction) is determined by angle σ between the beginning of said curve (longitudinal axis of the movable object) and by its zero value, in which there takes place previously mentioned sequence of changing the positive sign to the negative one. This means that said angle σ is the angle between said longitudinal axis of said movable object and said vector V.
It should be kept in mind that said zero values of said curve determine the position of the geographical parallel.
The north-south direction of true meridian, in its turn, is determined by the perpendicular to the west-east direction (by the perpendicular to said vector V).
Therefore, continuous control circuit is considered to be the device transforming periodical electrical signal coming from said device of horizontal acceleration to the graphical periodical image of the same kind. Said graphical image can, in particular, be reflected on the radar display, computer, and electron-ray tube.
By its zero value given to be counted off from the value of the corresponding to the longitudinal axis of the movable object determination is made of true course α. Under this course we mean an angle between the northern direction of true meridian Nu and said longitudinal axis of the movable object. Due to the above, the simplest type of said continuous control scheme, in particular, used can be made of the electron-ray tube.
For eliminating any harmful influence of external magnetic fields (the Earth, movable object, etc.) said vessels of said device of the horizontal acceleration and said road electromagnet are provided with the screens (displays).
Since the speed of rotating said rotor of said device electric motor is considered to be very high, the present technical solution can be used in higher polar latitudes even despite small values of the speed v in these latitudes.
The present technical solution is illustrated by way of the drawing on which there is a structural (functional) scheme shown of the device for determining true meridian.
On said drawing there are not pressure sensors shown, but there are the points shown whereon pressures of these sensors are determined.
In addition, not to make said drawing more complex, there are not any electric connections of said pressure sensors shown with current-conducting rings. Said rings are said to be connected with the axle (shaft) of said device electric motor. They are considered to slide while rotating along the current-conducting electric brushes, from which the signals are supplied to the differential scheme. Said rings and electric brushes are not shown on said drawing either.
The method provided is based on fixing the direction of said vector of linear velocity produced by rotating a heavenly body, the terrestrial globe, in particular, by said linear acceleration to equal to zero, it being induced created by changing said projection of said vector on the plane, containing said points of determining pressure symmetrically located relative to the vertical and induced rotation around it.
The equality of said linear acceleration being to zero is determined by zero difference of pressures in said points.
Said points are located similarly in similar inner cavities of said vessels (filled with flowing medium) similarly located on the parallel straight lines along the vertical.
On the drawing provided there is a structural (functional) scheme of one of possible devices shown, it implementing the method to be provided for determining true meridian of the movable object.
Said device is considered to comprise interconnected between each other said device of horizontal acceleration 1, said device electric motor 2, said road platform 3 with said road line 4 drawn thereon, said road electromagnet 5 with said core 6, said road electric motor 7 and said control circuit 8.
Said vessels of said device of horizontal acceleration 1 are fastened on said axle (shaft) of said device electric motor 2 in the way that said parallel straight lines, whereon said points of determining pressure L1 and L2 to be similarly located are considered to be parallel to the axle (shaft) of said electric motor.
Said body of said road electric motor is considered to be fastened on said road platform 3 so that, in the horizontal position thereof, said axle (shaft) of said rotor of said device electric motor be located along the vertical.
Said plane of determining pressure (containing said points of determining g pressure L1 and L2) of said device of horizontal acceleration 1 in the initial position (before the beginning of the rotation) are considered to be located along some chosen line of the movable object, particularly, for more convenience, along said longitudinal axis of said movable object (or along the line parallel to it).
Said road line 4 to have been drawn (on said road platform 3) in the initial position is also set in this direction.
Said road electromagnet 5 is fastened on said road platform 3 so that said core 6 is located on said platform perpendicular to said road line 4 and symmetrically relative to said points of determining L1 and L2 pressure in the initial position of said plane.
With said road platform there is firmly connected said axle (shaft) of said road electric motor 7 so that its axle (shaft) is located along the vertical.
If said body of said movable object is used as a horizontal platform [2], then it can be used as a road platform.
For said road electromagnet 5 to be able to influence said sensitive elements of said pressure sensors (meaning said points of determining pressure L1 and L2) in the same way, in terms of the value as said vector W, but opposite by the sign, there are the following measure provided for:
On winding of said electromagnet 5 there is said signal of said ground speed w supplied, and on said road electric motor 7 there is said signal of angle ε supplied (ε—the angle between longitudinal axis of the movable object and vector of ground speed W).
Said road electric motor 7 receiving said signal of angle ε, is expected to rotate said road platform 3 by said angle. Therefore, magnetic induction produced by said road electromagnet 5 turns always out to be perpendicular to said vector W, and by the value is determined by the value w.
With rotating said vessels of said device of horizontal acceleration (by means of said device electric motor 2) the value of the projection on the plane of determining pressure is considered to change, both said vector W and magnetic induction.
Due to said change of the projection of said vector W in said plane of determining pressure along said axis of sensitivity ξ of said device 1 there occurs said linear acceleration, it being considered to be harmful.
When with rotating said plane of determining pressure (said axis of sensitivity ξ) is perpendicular to said vector W, said projection on said plane will be equal to zero, and said linear acceleration will be maximum. Simultaneously, said projection of magnetic induction on said plane is expected to be maximum. And since the value of magnetic induction is determined by the signal W, then resulting influence of said projections is expected to be equal to zero. Thus, at the output of the differential scheme 8 (at the output of said device 1) no changes will occur. Thus, any harmful influence of said vector W will be eliminated.
When with rotating said plane of determining pressure (said axis of sensitivity ξ) is congruent with said vector W, its projection will be maximum, and said linear acceleration will be equal to zero. Simultaneously, since magnetic induction is perpendicular to said plane of determining pressure (axis of sensitivity ξ) and symmetrical relative to said points L1 and L2, then its influence is expected to be zero.
Thus, it means that in this case the influence of said vector W is also eliminated.
Since with rotating the vessels of said device 1 the projection of said vector W and magnetic induction change with rotating in the same way (in conformity with one and the law) and their influences are equal by the value and opposite by the sign, then it goes without saying that any harmful influence of said vector W is always eliminated.
At the same time, with rotating said vessels of said device 1 there occurs change of said projection on said plane (on said axis of sensitivity ξ) of said vector V of linear velocity v caused by the rotation of a heavenly body, particularly, the terrestrial globe. Due to the above, in said plane there occurs linear acceleration determined by the difference of pressures in said points L1 and L2 determined by said pressure sensors.
When said plane (axis of sensitivity ξ) is congruent with said vector V, this acceleration α is equal to 0 (α=0). In this case, at the output of said device 1 the signal will be equal to 0.
By this zero signal determination is made of true meridian perpendicular to said vector V.
For fixing said zero signal (α=0) i.e. true meridian, said control circuit 8 serves, wherein a signal from said device 1 is supplied. Said circuit can be discreet [3] and continuous.
In the discreet control circuit with α=0 the rotation of said rotor of said device electric motor 2 stops, and said plane of determining pressure, said axis of sensitivity ξ and road 4 turn out to be superposed with said vector V i.e. perpendicular to true meridian.
Herewith, the perpendicular to said plane (as well as to the axis ξ) containing said points of determining pressure is considered to indicate true meridian.
In the continuous control circuit the rotation of said device electric motor 2 is considered to occur uninterruptedly. Therefore, the output signal of said device 1 is of periodical character (with the period of 360°).
In the initial position (before rotating) said plane of determining pressure, i.e. said plane containing said points of determining pressure, is set in the direction of the line of the movable object chosen, particularly, of its longitudinal axis.
Therefore, with rotating, the beginning of the curve of said signal corresponds to the initial position of said plane (axis of sensitivity ξ), i.e. its longitudinal axis of the movable object.
Due to the above, the angle counted off from the beginning of said curve till its zero value is considered to determine the position of the geographical parallel.
In its turn, zero value of said curve, wherein there occurs the change of its positive value for the negative one is considered to determine the direction of said vector V (west-east).
Thus, the angle counted off from the beginning of said curve till said zero value is the angle σ between said longitudinal axis of the movable object and vector V.
In said continuous control circuit 8 the determination of said angle σ takes place.
This enables it to give off the data about true meridian by means of giving off the signal of true course α, graphical image of said curve or flash (stray lighting) on the radar screens (displays), computer, electron-ray tube.
Thus, the operation of the device provided is tracing (by the angle ε) the direction said vector V and determining true meridian by zero signal of linear acceleration, in particular, by determining true course α.
Since said operation is not connected with the usage of magnetic field of a heavenly body, particularly, the terrestrial globe, then elimination of its harmful influence as well as magnetic field of the mobile object is implemented by means screening.
The most distinguishing feature of the technical solution provided is a new solution for determining true meridian.
The main considerable advantages and merits of the technical solution provided are:
The authors have found the solution of eliminating any harmful influence of centrifugal (centripetal) accelerations occurring with rotating of the movable object around instantaneous center of rotation, irrespective of its position.
| Number | Date | Country | Kind |
|---|---|---|---|
| 186077 | Sep 2007 | IL | national |
