Multi-sensor fusion correction-based north-seeking system and north-seeking method

Abstract

The invention discloses a north-seeking system and a north-seeking method based on multi-sensor fusion correction. Acceleration sensors and piezoelectric sensors are uniformly arranged on a rotary table of the Coriolis effect rotary table in the circumferential direction; the infrared receiver is arranged on the turntable; the infrared emitter and the infrared receiver are oppositely arranged and are fixed; one end of the magnetic coupler is connected with the rotary conductor, and the other end is connected with the upper half rotating shaft; the lower half rotating shaft is connected with a motor output end; signal output ends of the acceleration sensor, the piezoelectric sensor and the infrared receiver are connected with a signal input end of the processor through the rotary conductor, data of the piezoelectric sensor are utilized to correct data of the acceleration sensor, and data of the infrared receiver are utilized to divide periods. And performing northbound angle calculation by using the corrected acceleration data in each period. The vibration interference is effectively corrected through a mode of fusing multiple sensors, the signal-to-noise ratio of an output signal of the acceleration sensor is improved, and the calculation precision of the north angle is improved.

Description

Technical Field

[0001] The present invention relates to the field of north-seeking technology, and in particular to a north-seeking system and method based on multi-sensor fusion correction. Background Art

[0002] North-finding technology refers to the use of various devices and methods to determine the Earth's true north. Inertial north-finding, one such method, uses inertial components such as gyroscopes and accelerometers to measure the north component of the Earth's rotational angular velocity, thereby determining true north. Inertial components are unaffected by external environmental conditions such as magnetic fields, weather conditions, and terrain obstructions. They offer advantages such as long-term stable operation, high accuracy, complete autonomy, and short measurement times. They are frequently used in geophysical exploration, geodesy, coal mining, and oil drilling.

[0003] Gyroscope systems are complex, and different types of gyroscopes often face a trade-off between small size, high precision, high efficiency, strong anti-interference capabilities, and low cost. Therefore, developing high-precision, small, efficient, and low-cost north-finders remains an important research topic in the field of inertial navigation.

[0004] The existing accelerometer-based north-finding solution places the accelerometer on a symmetrical connecting rod turntable with its sensitive axis pointing vertically upward. Driven by a motor, the turntable moves at a constant speed, and the accelerometer measures the absolute acceleration at four reference points to calculate the azimuth angle. However, the connecting rod turntable consists of a linked connecting rod and hinge. Placing the accelerometer directly on either side of the connecting rod results in uneven radial mass, leading to eccentricity and significant vibration during high-speed rotation. The resulting vibration acceleration significantly reduces the signal-to-noise ratio of the accelerometer output signal, hindering the accuracy of the north angle calculation. Summary of the Invention

[0005] The present invention provides a north-seeking system and a north-seeking method based on multi-sensor fusion correction, thereby effectively correcting vibration interference, improving the signal-to-noise ratio of the acceleration sensor output signal, and thus improving the calculation accuracy of the north angle.

[0006] The present invention provides a north-seeking system based on multi-sensor fusion correction, comprising: a rotating conductor, a Coriolis effect rotating table, an acceleration sensor, a piezoelectric sensor, an infrared transmitter, an infrared receiver, a magnetic coupling, a motor and a processor; the Coriolis effect rotating table is formed by integrating a turntable and a rotating shaft; two acceleration sensors and two piezoelectric sensors are evenly arranged on the turntable of the Coriolis effect rotating table along the circumferential direction, and the two acceleration sensors are symmetrically arranged, and the two piezoelectric sensors are also symmetrically arranged; the infrared receiver is arranged on the turntable; the infrared transmitter and the infrared receiver are arranged opposite to each other and are fixed; one end of the magnetic coupling is connected to the rotating conductor, and the other end of the magnetic coupling is connected to the upper half of the rotating shaft of the Coriolis effect rotating table, and the lower half of the rotating shaft of the Coriolis effect rotating table is connected to the output end of the motor; the motor drives the Coriolis effect rotating table to rotate at a set speed; the signal output ends of the acceleration sensor, the piezoelectric sensor and the infrared receiver are communicatively connected to the signal input end of the processor through the rotating conductor.

[0007] Specifically, the distances between the two acceleration sensors and the two piezoelectric sensors and the axis of the Coriolis effect rotating table are equal.

[0008] Specifically, the infrared receiver is arranged at a position halfway between the line connecting the piezoelectric sensor and the axis of the rotating shaft; and only when the infrared receiver is facing the infrared transmitter, the infrared receiver generates a high level and outputs a signal.

[0009] Specifically, positioning and mounting holes are uniformly opened along the circumference of the turntable, and the two acceleration sensors and the two piezoelectric sensors are respectively arranged in each positioning and mounting hole.

[0010] The present invention also provides a north-finding method applicable to the above-mentioned north-finding system, comprising:

[0011] By formula a z =a k -a y =g+a0+2Ωrω N The acceleration a after fusion correction is calculated by cos(Ωt+θ)+σ z ; Among them, a k is the measurement value of the acceleration sensor, a y is the measured value of the piezoelectric sensor, g is the acceleration due to gravity, a0 is the zero bias of the acceleration sensor, Ω is the rotation angular velocity of the Coriolis effect rotating table, r is the distance from the sensitive axis of the acceleration sensor to the axis center of the Coriolis effect rotating table, ω Nis the north component of the Earth's rotational angular velocity at the location of the Coriolis effect rotating platform, θ is the north angle, and σ is the output noise of the acceleration sensor and the piezoelectric sensor;

[0012] The output noise σ is filtered out by a filter to obtain the filtered north angle solution equation a=2Ωrω N cos(Ωt+θ);

[0013] The north angle θ is obtained by fitting using the least squares method.

[0014] Specifically, it also includes:

[0015] By formula Calculate ω N ; where ω is the angular velocity of the Earth's rotation, is the latitude of the location of the Coriolis effect rotating platform.

[0016] Specifically, filtering out the output noise σ through a filter includes:

[0017] The DC component and output noise σ in the signal are filtered out using a zero-phase high-pass filter and a zero-phase low-pass filter.

[0018] One or more technical solutions provided in the present invention have at least the following technical effects or advantages:

[0019] The Coriolis effect rotating table is an integrated turntable and shaft. Two accelerometers and two piezoelectric sensors are evenly arranged along the circumference of the turntable. An infrared receiver is also mounted on the turntable. An infrared transmitter and infrared receiver are positioned opposite and fixed to each other. One end of a magnetic coupling is connected to a rotating conductor, and the other end of the magnetic coupling is connected to the upper half of the Coriolis effect rotating table shaft. The lower half of the Coriolis effect rotating table shaft is connected to the output of a motor. The signal outputs of the accelerometers, piezoelectric sensors, and infrared receivers are connected to the signal inputs of a processor via a rotating conductor. A motor drives the Coriolis effect rotating table at a set speed. The output data of the accelerometers, piezoelectric sensors, and infrared receivers are synchronously collected. The output data of the piezoelectric sensors is used to correct the output data of the accelerometers. The output data of the infrared receiver is divided into cycles, and the corrected accelerometer data from each cycle is used to calculate the north angle. Through a multi-sensor fusion approach, vibration interference is effectively corrected, the signal-to-noise ratio of the accelerometer output signal is improved, and the accuracy of the north angle calculation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of a north-seeking system based on multi-sensor fusion correction provided by an embodiment of the present invention;

[0021] Figure 2 for Figure 1 A top view of the Zhongke effect rotating stage 2;

[0022] Figure 3 A schematic diagram of a north-finding method according to an embodiment of the present invention;

[0023] Among them, 1-rotating conductor, 2-Coriolis effect rotating table, 3-acceleration sensor, 4-piezoelectric sensor, 5-infrared transmitter, 6-infrared receiver, 7-motor, 8-magnetic coupling, 9-bearing, 10-first fixed platform, 11-second fixed platform, 12-third fixed platform, 201-wire hole. DETAILED DESCRIPTION

[0024] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0025] like Figure 1 and Figure 2As shown, the north-seeking system based on multi-sensor fusion correction provided by an embodiment of the present invention includes: a rotating conductor 1, a Coriolis effect rotating table 2, an acceleration sensor 3, a piezoelectric sensor 4, an infrared transmitter 5, an infrared receiver 6, a motor 7, a magnetic coupling 8, a bearing 9 and a processor; the Coriolis effect rotating table 2 is formed by integrating a turntable and a rotating shaft; two acceleration sensors 3 and two piezoelectric sensors 4 are evenly arranged on the turntable of the Coriolis effect rotating table 2 along the circumferential direction, and the two acceleration sensors 3 are symmetrically arranged, and the two piezoelectric sensors 4 are also symmetrically arranged; the infrared receiver 6 is arranged on the turntable of the Coriolis effect rotating table 2; the infrared transmitter 5 and the infrared receiver 6 are arranged opposite to each other and are fixed on the lower side of the second fixed platform 11; when and only when the infrared receiver 6 is facing the infrared transmitter 5, the infrared receiver 6 generates a high-level signal and sends it to the processor. One end of the magnetic coupling 8 is connected to the rotating conductor 1, and the other end of the magnetic coupling 8 is connected to one end of the upper half shaft of the Coriolis effect rotating table 2. The lower half shaft of the Coriolis effect rotating table 2 is connected to the output end of the motor 7, and a wire hole 201 is left on the upper half shaft of the Coriolis effect rotating table 2; the rotating conductor 1 is arranged on the first fixed platform 10, and the upper half shaft of the Coriolis effect rotating table 2 is connected to the inner wall of the second fixed platform 11 through the bearing 9, and the lower half shaft of the Coriolis effect rotating table 2 is connected to the inner wall of the third fixed platform 12 through the bearing 9; the motor 7 drives the Coriolis effect rotating table 2 to rotate at a set speed; the signal output ends of the acceleration sensor 3, the piezoelectric sensor 4 and the infrared receiver 6 are communicatively connected to the signal input end of the processor through the rotating conductor 1. The output data of the acceleration sensor 3, the piezoelectric sensor 4 and the infrared receiver 6 are collected synchronously. The output data of the acceleration sensor 3 is corrected using the output data of the piezoelectric sensor 4. The output data of the infrared receiver 6 is divided into periods. The north angle is calculated using the corrected data of the acceleration sensor 3 in each period.

[0026] In order to make the vibration responses of the acceleration sensor 3 and the piezoelectric sensor 4 consistent, thereby improving the north-seeking accuracy, the distances between the two acceleration sensors 3 and the two piezoelectric sensors 4 and the axis of the Coriolis effect rotating table 2 are equal.

[0027] In order to avoid mutual influence and positioning error between components and thus improve north-seeking accuracy, the infrared receiver 6 is arranged at half the position of the line connecting the piezoelectric sensor 4 and the axis of the Coriolis effect rotating table 2.

[0028] The structure of the embodiment of the present invention is described in detail. Positioning and mounting holes are evenly arranged along the circumference of the turntable. Two acceleration sensors 3 and two piezoelectric sensors 4 are respectively arranged in each positioning and mounting hole.

[0029] In this embodiment, the motor 7 is a hollow shaft motor.

[0030] like Figure 3 As shown, the north-finding method provided in the embodiment of the present invention is applicable to the north-finding system described above, including:

[0031] Step 1: Use the formula

[0032] a z =a k -a y =g+a0+2Ωrω N cos(Ωt+θ)+σ

[0033] Calculate the acceleration a after fusion correction z ; Among them, a k is the measurement value of acceleration sensor 3, a y is the measurement value of the piezoelectric sensor 4, g is the acceleration due to gravity, a0 is the zero bias of the acceleration sensor 3, Ω is the rotation angular velocity of the Coriolis effect turntable 2, r is the distance from the sensitive axis of the acceleration sensor 3 to the axis center of the Coriolis effect turntable 2, ω N is the north component of the Earth's rotational angular velocity at the location of the Coriolis effect rotating platform 2, θ is the north angle, and σ is the output noise of the acceleration sensor 3 and the piezoelectric sensor 4;

[0034] This step is explained in detail. According to the acceleration synthesis principle, the acceleration sensor north-seeking equation is determined:

[0035] a k =g+a0+a 振 +2Ωrω N cos(Ωt+θ)+σ1

[0036] The piezoelectric sensor 4 is tested to measure only vibrations according to its characteristics, namely:

[0037] a y =a 振 +σ2

[0038] Where a 振 is the vibration acceleration generated by the Coriolis effect rotating table when it rotates, σ1 and σ2 are the output noise of acceleration sensor 3 and piezoelectric sensor 4 respectively.

[0039] a k and a y Subtracting them yields:

[0040] a z =a k -a y =g+a0+2Ωrω N cos(Ωt+θ)+σ

[0041] Step 2: Filter out the output noise σ and obtain the filtered north angle solution equation a=2Ωrω N cos(Ωt+θ);

[0042] Specifically, the output noise σ is filtered out by a filter, including:

[0043] The DC component and output noise σ in the signal are filtered out using a zero-phase high-pass filter and a zero-phase low-pass filter.

[0044] Step 3: Use the least squares method to fit and solve to get the north angle θ.

[0045] In order to calculate ω N , also includes:

[0046] By formula Calculate ω N ; where ω is the angular velocity of the Earth's rotation, is the latitude of the location of Coriolis effect rotating platform 2.

[0047] In summary, the embodiments of the present invention provide a north-seeking system and a north-seeking method based on multi-sensor fusion correction, which effectively corrects vibration interference and improves the signal-to-noise ratio of the output signal of the acceleration sensor 3, thereby improving the accuracy of the north angle calculation.

[0048] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0049] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0050] These computer program instructions may 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 produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0051] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0052] Any details not described in the embodiments of the present invention are well-known to those skilled in the art. Finally, it should be noted that the above embodiments are only intended to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or equivalents should be included in the scope of the claims of the present invention.

Claims

1. A north-seeking system based on multi-sensor fusion correction, characterized in that: include: A rotating conductor, a Coriolis effect rotating table, an acceleration sensor, a piezoelectric sensor, an infrared transmitter, an infrared receiver, a magnetic coupling, a motor and a processor; the Coriolis effect rotating table is formed by integrating a turntable and a rotating shaft; the two acceleration sensors and the two piezoelectric sensors are evenly arranged on the turntable of the Coriolis effect rotating table along the circumferential direction, and the two acceleration sensors are symmetrically arranged, and the two piezoelectric sensors are also symmetrically arranged; the infrared receiver is arranged on the turntable; the infrared transmitter and the infrared receiver are arranged opposite to each other and are fixed; one end of the magnetic coupling is connected to the rotating conductor, and the other end of the magnetic coupling is connected to the upper half shaft of the Coriolis effect rotating table, and the lower half shaft of the Coriolis effect rotating table is connected to the output end of the motor; the motor drives the Coriolis effect rotating table to rotate at a set speed; the signal output ends of the acceleration sensor, the piezoelectric sensor and the infrared receiver are communicatively connected to the signal input end of the processor through the rotating conductor.

2. The north-seeking system based on multi-sensor fusion correction according to claim 1, characterized in that: The distances between the two acceleration sensors and the two piezoelectric sensors and the axis of the Coriolis effect rotating table are equal.

3. The north-seeking system based on multi-sensor fusion correction according to claim 1, characterized in that: The infrared receiver is arranged at a position halfway between the line connecting the piezoelectric sensor and the axis of the rotating shaft.

4. The north-seeking system based on multi-sensor fusion correction according to claim 1, characterized in that: Positioning and mounting holes are evenly arranged on the turntable along the circumferential direction, and the two acceleration sensors and the two piezoelectric sensors are respectively arranged in each of the positioning and mounting holes.

5. A north-finding method, applicable to the north-finding system according to any one of claims 1 to 4, characterized in that: include: By formula a z =a k -a y =g+a0+2Ωrω N The acceleration a after fusion correction is calculated by cos(Ωt+θ)+σ z ; Among them, a k is the measurement value of the acceleration sensor, a y is the measured value of the piezoelectric sensor, g is the acceleration due to gravity, a0 is the zero bias of the acceleration sensor, Ω is the rotation angular velocity of the Coriolis effect rotating table, r is the distance from the sensitive axis of the acceleration sensor to the axis center of the Coriolis effect rotating table, ω N is the north component of the Earth's rotational angular velocity at the location of the Coriolis effect rotating platform, θ is the north angle, and σ is the output noise of the acceleration sensor and the piezoelectric sensor; The output noise σ is filtered out by a filter to obtain the filtered north angle solution equation a=2Ωrω N cos(Ωt+θ); The north angle θ is obtained by fitting using the least squares method.

6. The north-seeking method according to claim 5, wherein: Also includes: By formula Calculate ω N ; where ω is the angular velocity of the Earth's rotation, is the latitude of the location of the Coriolis effect rotating platform.

7. The north-seeking method according to claim 5 or 6, wherein: The step of filtering out the output noise σ by a filter comprises: The DC component and output noise σ in the signal are filtered out using a zero-phase high-pass filter and a zero-phase low-pass filter.

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