SU1083073A1 - Magnetic compass - Google Patents

Abstract

A MAGNETIC COMPASS, containing a magnetically sensitive element mounted in a damping fluid together with an indicator disk with the possibility of rotation around a vertical axis, and a disk angle indication system, characterized in that, in order to improve the accuracy with continuous recording of the angular position, the disk is made with a side surface, the distance of points to the axis of rotation smoothly changes, and the display system of the angular position of the disk is implemented as a piezoelectric transceiver transform fir for measuring distances to the side surface of the disc.

Description

The invention is inclined to navigate C1-10NK measurements, as well as to magnetic compasses with remote position recording, used in particular in meteorological and hydrological investigations. Magnetic compasses are known with a variety of systems for remotely registering the magnetic course by generating an electrical signal proportional to the angle of rotation relative to the Earth's magnetic meridian tlH. Along with contact devices for retrieving information with low accuracy and low reliability, contactless systems have also been used in such compasses, in which a printed circuit for inductive positioning is applied to a disk rotating together with a compass needle in a damping fluid around a vertical axis. arrows C 23. Compasses with a similar system of remote registration, however, have a very sensitive sensitivity to the effects of magnetic interference and require a rather complicated circuit to provide Continuous disc position indication. The closest to the proposed are magnetic compasses with a photoelectric indication system in which code tracks are formed on the disk, rotating together with a magnetic arrow or another magnetically sensitive element around the vertical axis, using a line of photodetectors. Compasses have an accuracy of the order of 1–1.5 ° C J. A further increase in accuracy in such compasses is extremely difficult, since it is associated with an increase in disk size or the number of tracks, as well as photoelectric converters. A different principle is used to determine the angular position of two objects rotating one relative to another by measuring the propagation time of ultrasonic oscillations in the medium between objects. The purpose of the invention is to improve the recording accuracy during continuous recording of the angular position of the disk. To achieve this goal, a magnetic compass containing a magnetically sensitive element mounted in a damping fluid together with an indicator disk can be rotated around a vertical axis, and a disk angular position indication system, the latter made with a lateral surface, the distance of points to the axis of rotation smoothly changing. The disc angle indication system is implemented as a piezoelectric transceiver transducer for measuring distances to the side surface of the disc. Fig. 1 is a structural diagram of a magnetic compass; Fig. 2 is a block diagram of a magnetic compass recording system in Fig. 3 — voltage diagrams at the inputs (outputs) of individual functional units of magnetic compass converters. The magnetic compass includes a housing 1, a filled damping liquid KocTbW, a magnetic sensitive element (MCE) in the form of, for example, two permanent magnets 2 mounted on disk 3, the latter is made in the form of a profiled cam, the distance of points of the lateral surface of which is to the axis A smoothly is changing. In the plane of the disk 3 is fixedly mounted piezoelectric transducer 5 ultrasonic vibrations. The side surface of the disk 3 serves as a reflector of ultrasonic vibrations emitted by the piezoelectric transducer 5. The piezoelectric transducer 5 is connected to the output (input) of the secondary transducer 6, which measures the distance to the disk. The disk 3 is oriented along the Earth's magnetic meridian, and depending on the angle of rotation of the disk 3 relative to the piezoelectric transducer 5, the distance L from the end to the side surface of the disk 3 changes. When a pulse of excitation from the generator 7 is applied to the piezoelectric transducer, the latter generates an ultrasonic pulse, which, after passing a double distance of 2L in the damping fluid, is converted into an electrical signal. The duration of the time interval, counted from the moment of application of the shock excitation pulse to the formation of the receiving electrical signal, is proportional to the rotation angle of the disk 3. When choosing a medium having a temperature coefficient of ultrasonic oscillation velocity close to zero (for example, 6% - ethanol solution in distilled water), the duration of the specified time interval is determined practically by the angle of rotation of the disk 3, For Measuring this angle, the sinusoidal signals of a controlled oscillator 8 containing, as a frequency-dependent element, counter-connected varicaps, whose capacitance changes under the influence of the control voltage, are normalized by the pulse former 9 and in the form of rectangular pulses (Fig. 3o) go to the input of the divider. 10 with a constant division factor. From the output, the dividers 10 pulses (Fig.35) are fed to the input of the pulse distributor 11, which specifies the sequence of operation of the functional blocks of the secondary converter 6. The interim location pulses at the outputs a, b and 6, the distributor 11 shown respectively in fig.Z & I g, d- By ;, the leading edge of the pulse from the output of the distributor 11 triggers the start of the generator 7 of the excitation pulses (Fig. Ze). The electrical signal from the output of the converter 5 (fig.Z.) is fed through the amplitude limiter 12 to the input of the comparator 13, gated by the signal from the output of the divider 10. From the output of the comparator 13 the normalized receiving signal (fig.Zi) is fed to, for example, the S input RS -trigger 14, which generates a pulse, the temporary location of the front front of which will almost correspond to the time of registration by the comparator 13 of the receiving signal. Setting the trigger 14 to its initial state is accomplished by a pulse from output B

0830734

the distributor 11. The output pulses of the trigger 14 (Fig.Zk) arrive at the control input of the key element

15 and informational entry of discriminator 16 duration, for example on

The D-input of the D-flip-flop clocked at the C-input by the leading edge of the pulse from the output 5 of the distributor 11 (Fig. 3g). If the period of the following 10 pulses from the output of the divider 10 is longer than the time t of the ultrasonic pulse propagation at a distance of 2L, then at the discriminator output

16 the signal of the logical unit 15 (fig.3l) will act, causing

through the key element 15 on I} 1 integrator 17 positive voltage increment (Fig. 3 l), leading to an increase in the frequency of the controlled generator 8 and, consequently, to a decrease in the pulse following period from the output of the divider 10. If the pulse following period from the output the divider 10 is less than the time Tf of the propagation of the ultrasonic pulse at a double distance (2L), then the output of the discriminator 16 will have a logical zero signal, causing through a key element

30 15 on the integrator 17 negative voltage increment, leading to a decrease in the frequency of the generator 8 and an increase in the pulse period from the output of the divider 10. Thus, in the established mode of operation

35 of the secondary transducer, the propagation times of the ultrasonic pulse at a distance of 2L and the period of pulses at the output of the divider 10 will be achieved.

40

The magnetic compass with the primary transducer, which has a disk in the Vada of the profiled cam, with the ultrasonic intermediate transducer and the frequency secondary transducer, has an internal multiplication factor with automatic frequency control, provides

..- h higher accuracy (0.5 °) and

, sensitivity (more than 10 Hz at 0.1), reliability of the design, continuity of the output signal of the measurement information, as well as the convenience of converting the output pulse frequency signal to another55

These types of electrical signals.

In the morning

6

0ve.2

Claims (3)

A MAGNETIC COMPASS containing a magnetically sensitive element mounted in a damping fluid together with an indicator disc rotatably around a vertical axis, and a system for indicating the angular position of the disc, characterized in that, in order to improve accuracy during continuous recording of the angular position, the disc is made with a side surface, the distance of the points of which to the axis of rotation changes smoothly, and the system for indicating the angular position of the disk is implemented as a piezoelectric disk. transceiver for measuring distances to the side surface 2. UK patent No. 1296703 class. G 01 C 17/26, 1972. 3. UK patent