North seeking device and north seeking method

Abstract

The invention discloses a north-seeking device and a north-seeking method. Acceleration sensors are symmetrically arranged on a rotating disc of the Coriolis rotating table. The position sensor is arranged on the rotating shaft; one end of the non-contact coupling is fixedly connected with the rotating shaft, and the other end of the non-contact coupling is connected with the output end of the motor; the signal output ends of the acceleration sensor and the position sensor are in communication connection with the signal input end of the processor through the rotation signal transmitter. The output data of the position sensor is utilized to perform period division, and the output data of the acceleration sensor in each period is utilized to perform northbound angle calculation. The integrated rotating table and a non-contact coupling structure are adopted, eccentricity and vibration caused by unbalanced radial mass distribution of the rotating table are remarkably reduced, the influence of vibration of a motor on output signals of the acceleration sensor is eliminated, the signal-to-noise ratio of the output signals of the acceleration sensor is effectively increased, and the reliability of the acceleration sensor is improved. And the operation stability and the service life of the north-seeking device are ensured while the north-seeking precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of north seeking, and in particular to a north seeking device and a north seeking method. Background Art

[0002] North seeking technology refers to the technology of determining the true north direction of the earth through various devices and methods. Inertial north seeking technology is one of them, which uses inertial elements such as gyroscopes and accelerometers to measure the northward component of the earth's angular velocity of rotation, so as to determine the true north direction. Inertial elements are not affected by external environmental conditions such as magnetic field interference, weather changes, terrain occlusion and other factors, and have the advantages of long-term stable operation, high precision, full autonomy, and short measurement time. They are often used in geophysical exploration, geodetic surveying, coal mining, oil drilling and other fields.

[0003] The gyroscope system has a complex structure, and there are generally contradictions among small volume, high precision, high efficiency, strong anti-interference and low cost for different types of gyroscopes. Therefore, researching a north seeker with high precision, small volume, high efficiency and low cost is still an important research topic in the field of inertial navigation.

[0004] The existing accelerometer north seeking scheme is to place the accelerometer on a turntable with a link symmetric structure, with the sensitive axis of the accelerometer vertically upward. The link structure turntable makes a uniform motion driven by a motor, and the azimuth angle is solved by measuring the absolute acceleration at four reference points through the accelerometer. The link structure turntable is composed of links and hinges connected together. The accelerometer is directly placed on both sides of the link. The unbalanced radial mass of the link will cause eccentricity and generate large vibrations during high-speed rotation. The output shaft of the servo motor is directly fixed to the turntable, which will bring the influence generated by the turntable eccentricity to the motor, shorten the service life of the device, and at the same time transmit the vibration of the motor to the turntable. The vibration acceleration generated by the vibration will seriously reduce the signal-to-noise ratio of the output signal of the accelerometer, which is not conducive to improving the accuracy of solving the northward angle. Summary of the Invention

[0005] The present invention provides a north seeking device and a north seeking method, which ensure the stability and service life of the north seeking device while improving the north seeking accuracy.

[0006] The present invention provides a north-seeking device, comprising: a rotation signal transmitter, a Coriolis rotating table, an acceleration sensor, a position sensor, a non-contact coupling, a motor and a processor; the Coriolis rotating table is integrally formed by a turntable and a rotating shaft; the acceleration sensors are symmetrically arranged on the turntable of the Coriolis rotating table; the position sensor is arranged on the rotating shaft; one end of the non-contact coupling is fixedly connected to the rotating shaft, and the other end of the non-contact coupling is connected to the output end of the motor; the motor drives the Coriolis rotating table to rotate at a constant rate in a non-contact manner; the signal output ends of the acceleration sensor and the position sensor are communicatively connected to the signal input end of the processor through the rotation signal transmitter.

[0007] Specifically, positioning and mounting holes are symmetrically distributed on the turntable, and the two acceleration sensors are respectively arranged in the positioning and mounting holes.

[0008] Specifically, the position sensor is a split-type optical position sensor.

[0009] The present invention also provides a north-seeking method, applicable to the north-seeking device as described above, comprising:

[0010] Using the output data of the position sensor for cycle division, and in the same cycle, taking n groups of the output data of the acceleration sensor to construct an equation system where a1…a n are the output data of the n groups of the acceleration sensor, d1 = -2Ωrω N sinθ, d2 = 2Ωrω N cosθ, d3 = g + a0 + σ, Ω is the angular velocity of the Coriolis rotating table, r is the distance from the sensitive axis of the acceleration sensor to the axis center of the rotating shaft of the Coriolis rotating table, ω N is the northward component of the angular velocity of the earth's rotation at the location of the Coriolis rotating table, θ is the northward angle, g is the acceleration due to gravity, a0 is the zero offset of the acceleration sensor, and σ is the output noise of the acceleration sensor;

[0011] Solving the equation system to obtain the values of d1, d2, and d3, and establishing a calculation equation for the northward angle

[0012] Calculating the northward angle θ by solving the calculation equation.

[0013] Specifically, it further comprises:

[0014] Calculating ω N = ωcosφ to obtain ω N ; where ω is the angular velocity of the earth's rotation, and φ is the latitude of the location of the Coriolis rotating table.

[0015] One or more technical solutions provided in the present invention have at least the following technical effects or advantages:

[0016] The Coriolis turntable is integrally formed by a turntable and a rotating shaft; the acceleration sensors are symmetrically arranged on the turntable of the Coriolis turntable; the position sensor is arranged on the rotating shaft; one end of the non-contact coupling is fixedly connected to the rotating shaft, and the other end of the non-contact coupling is connected to the output end of the motor; the motor drives the Coriolis turntable to rotate at a constant speed in a non-contact manner; the signal output ends of the acceleration sensor and the position sensor are communicatively connected to the signal input end of the processor. The output data of the position sensor is used for cycle division, and the output data of the acceleration sensor in each cycle is used for solving the northward angle. By adopting an integral structure turntable and a non-contact coupling structure, the eccentricity and vibration caused by the uneven radial mass distribution of the turntable are significantly reduced, the influence of the motor's own vibration on the output signal of the acceleration sensor is eliminated, the signal-to-noise ratio of the output signal of the acceleration sensor is effectively improved, and the stability and service life of the north-seeking device during operation are ensured while improving the north-seeking accuracy. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the north-seeking device provided by an embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of the principle of the north-seeking method provided by an embodiment of the present invention;

[0019] Wherein, 1 - rotation signal transmitter, 2 - Coriolis turntable, 3 - acceleration sensor, 4 - position sensor, 5 - non-contact coupling, 6 - motor. Detailed Embodiments

[0020] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the drawings in the specification and specific embodiments.

[0021] As Figure 1As shown in the figure, the north-seeking device provided by the embodiment of the present invention includes: a rotation signal transmitter 1, a Coriolis rotating table 2, an acceleration sensor 3, a position sensor 4, a non-contact coupling 5, a motor 6 and a processor; the Coriolis rotating table 2 is integrally formed by a turntable and a rotating shaft. Two acceleration sensors 3 are symmetrically arranged on the turntable on both sides of the rotating shaft; the position sensor 4 is arranged on the rotating shaft; one end of the non-contact coupling 5 is fixedly connected to the rotating shaft, and the other end of the non-contact coupling 5 is connected to the output end of the motor 6; the signal output ends of the acceleration sensor 3 and the position sensor 4 are communicatively connected to the signal input end of the processor through the rotation signal transmitter 1. The motor 6 drives the Coriolis rotating table 2 to rotate at a constant speed in a non-contact manner. The output data of the acceleration sensor 3 and the position sensor 4 are synchronously collected and uploaded to the processor for northward angle calculation. Specifically, the position sensor 4 outputs a high level every 360° of rotation to divide the rotation period, and the output data of the acceleration sensor 3 in each period is used for northward angle calculation.

[0022] Specifically describe the structure of the embodiment of the present invention. Positioning and mounting holes are symmetrically distributed on the turntable, and the two acceleration sensors 3 are respectively arranged in the positioning and mounting holes. The center position of the positioning and mounting hole has a certain distance from the axis of the Coriolis rotating table 2, and the mass of the material of the Coriolis rotating table 2 removed by the opening is the same as the mass of the acceleration sensor 3.

[0023] Specifically, the top end of the rotating shaft is coaxially and tightly connected to the rotor of the rotation signal transmitter 1, and the position sensor 4 is coaxially and tightly connected to the bottom end of the rotating shaft.

[0024] In this embodiment, the position sensor 4 is a split optical position sensor. The motor 6 is a brushless motor.

[0025] As Figure 2 shown, the north-seeking method provided by the embodiment of the present invention is applicable to the north-seeking device as described above, including:

[0026] Step 1: Use the output data of the position sensor 4 to divide the period. In the same period, take n groups of output data of the acceleration sensor 3 to construct an equation system

[0027] where a1…a n is the output data of n groups of acceleration sensors 3, d1 = -2Ωrω N sinθ, d2 = 2Ωrω N cosθ, d3 = g + a0 + σ, Ω is the angular velocity of the Coriolis rotating table 2, r is the distance from the sensitive axis of the acceleration sensor 3 to the axis of the rotating shaft of the Coriolis rotating table 2, ω N$\omega$ is the northward component of the angular velocity of the Earth's rotation at the location of the Coriolis turntable 2, $\theta$ is the northward angle, $g$ is the acceleration due to gravity, $a_0$ is the zero bias of the acceleration sensor 3, and $\sigma$ is the output noise of the acceleration sensor 3;

[0028] Specifically explain this step. According to the principle of acceleration synthesis, determine the north-seeking equation of the acceleration sensor:

[0029] $a = g + a_0 + 2\Omega r\omega$ N $\cos(\Omega t + \theta) + \sigma$

[0030] It can be seen from the north-seeking equation that increasing the rotation speed of the Coriolis turntable 2 can increase the Coriolis acceleration.

[0031] According to the trigonometric function sum and difference angle formula, the above formula can be written in the following form:

[0032] $a = d_1\sin\Omega t + d_2\cos\Omega t + d_3$

[0033] Where $d_1 = -2\Omega r\omega$ N $\sin\theta$, $d_2 = 2\Omega r\omega$ N $\cos\theta$, $d_3 = g + a_0 + \sigma$.

[0034] Use the output data of the position sensor 4 to perform period division. In the same period $n$ ($n > 100$), the digital model output by the acceleration sensor 3 is:

[0035] $a$ j $= d_1\sin\Omega t$ j $+ d_2\cos\Omega t$ j $+ d_3$ ($j = 1, 2, 3, \ldots, n$)

[0036] Take $n$ groups of output data of the acceleration sensor 3 to construct a system of equations:

[0037]

[0038] Step 2: Solve the system of equations to obtain the values of $d_1$, $d_2$, and $d_3$, and establish the calculation equation for the northward angle

[0039] Step 3: Solve the calculation equation to obtain the northward angle $\theta$.

[0040] In order to calculate $\omega$ N , it also includes:

[0041] Calculate $\omega$ through the formula $\omega$ N $= \omega\cos\varphi$ N ; where $\omega$ is the angular velocity of the Earth's rotation, and $\varphi$ is the latitude of the location of the Coriolis turntable 2.

[0042] In summary, the embodiments of the present invention provide a north-seeking device and a north-seeking method, which improve the north-seeking accuracy while ensuring the stability and service life of the north-seeking device.

[0043] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0044] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the specified functions in Figure 1 one or more of the processes Figure 1 or multiple processes and / or blocks

[0045] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device realizes the specified functions in Figure 1 one or more of the processes Figure 1 or multiple processes and / or blocks

[0046] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for realizing the specified functions in Figure 1 one or more of the processes Figure 1 or multiple processes and / or blocks

[0047] Where the embodiments of the present invention are not described in detail are well-known technologies to those skilled in the art. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A north-seeking device, characterized in that, Including: A rotation signal transmitter, a Coriolis rotating table, an acceleration sensor, a position sensor, a non-contact coupling, a motor, and a processor; The Coriolis rotating table is integrally formed by a turntable and a rotating shaft; the acceleration sensors are symmetrically arranged on the turntable of the Coriolis rotating table; the position sensor is arranged on the rotating shaft; one end of the non-contact coupling is fixedly connected to the rotating shaft, and the other end of the non-contact coupling is connected to the output end of the motor; the motor drives the Coriolis rotating table to rotate at a constant rate in a non-contact manner; the signal output ends of the acceleration sensor and the position sensor are communicatively connected to the signal input end of the processor through the rotation signal transmitter.

2. The north-seeking device according to claim 1, wherein Positioning and mounting holes are symmetrically distributed on the turntable, and the two acceleration sensors are respectively arranged in the positioning and mounting holes.

3. The north-seeking device according to claim 1 or 2, characterized in that, The position sensor is a split-type optical position sensor.

4. A north-seeking method, applicable to the north-seeking device described in any one of claims 1-3, characterized in that, Including: Perform cycle division using the output data of the position sensor. In the same cycle, take n sets of the output data of the acceleration sensor to construct an equation system where a1…a n are the output data of n sets of the acceleration sensor, d1 = -2Ωrω N sinθ, d2 = 2Ωrω N cosθ, d3 = g + a0 + σ, Ω is the angular velocity of the Coriolis turntable's self-rotation, r is the distance from the sensitive axis of the acceleration sensor to the axis center of the Coriolis turntable's rotation axis, ω N is the northward component of the angular velocity of the Earth's rotation at the location of the Coriolis turntable, θ is the northward angle, g is the acceleration due to gravity, a0 is the zero offset of the acceleration sensor, and σ is the output noise of the acceleration sensor; Solve the system of equations to obtain the values of d1, d2, and d3, and establish the solution equation for the northward angle. Solve the solution equation to obtain the northward angle θ.

5. The north-seeking method according to claim 4, characterized in that, Further including: Calculated through the formula to obtain ω N ; where ω is the angular velocity of the Earth's rotation, is the latitude of the location where the Coriolis rotating table is located.

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