Optical fiber inertial navigation system based on X-axis MEMS accelerometer

Abstract

The invention relates to the technical field of high-precision inertial navigation, and discloses an X-axis MEMS accelerometer-based optical fiber inertial navigation system, which comprises an optical fiber gyroscope assembly, an MCU processor, an X-axis MEMS accelerometer, a Y-axis MEMS accelerometer and a Z-axis MEMS accelerometer, and also comprises a power supply module, the power supply module comprises a power supply and a step-down converter, and the step-down converter is connected with the MCU processor. The power conversion module is used for converting an externally input 9V-36V power supply into a 5V power supply required by the MCU processor, the X-axis MEMS accelerometer, the Y-axis MEMS accelerometer and the Z-axis MEMS accelerometer, and is also used for converting the externally input 9V-36V power supply into a 3.3 V power supply required by the fiber-optic gyroscope assembly; the satellite navigation module comprises an anti-interference base band integrated SoC chip, an anti-interference double-channel radio frequency chip and a satellite navigation receiver and is used for being connected with an external satellite navigation antenna, providing GNSS positioning information for an inertial navigation system and achieving combined navigation, the combination of a high-precision X-axis MEMS accelerometer and a fiber-optic gyroscope is adopted, the inertial navigation size and weight can be greatly reduced, and the integrated satellite navigation system has the advantages of being simple in structure, low in cost and high in reliability. And power consumption and cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of high-precision inertial navigation, and in particular to a fiber optic inertial navigation system based on an X-axis MEMS accelerometer. Background Art

[0002] MEMS (Micro-Electro-Mechanical System) is a rapidly developing processing technology that can manufacture a micro-electromechanical system on a silicon wafer of a few millimeters or even smaller. MEMS accelerometer is an accelerometer manufactured using MEMS technology. It is a new type of acceleration sensor after quartz flexure accelerometer and vibration beam accelerometer. It has the characteristics of small size, light weight, low power consumption and low cost.

[0003] The use of high-precision MEMS accelerometers as accelerometer sensor units in inertial navigation systems is an important development direction of current inertial navigation systems. Compared with fiber-optic inertial navigation systems that use traditional quartz flexible accelerometers, there is no need to equip ±15V power supplies, IF conversion circuits, etc. MEMS accelerometers are directly soldered on the circuit board as components, thus greatly reducing the size and weight of the inertial navigation system, and reducing power consumption and costs. Summary of the invention

[0004] The purpose of the present invention is to provide an inertial navigation system based on a combination of three X-axis MEMS accelerometers and a three-axis fiber optic gyroscope. The three X-axis accelerometers, an MCU processor, an interface circuit, a satellite navigation module, and a power module are combined on one circuit board through a rigid-flexible printed circuit board, thereby solving the problems of large size and high power consumption of traditional fiber optic inertial navigation.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: A fiber optic inertial navigation system based on an X-axis MEMS accelerometer comprises a fiber optic gyroscope component, an MCU processor, an X-axis MEMS accelerometer, a Y-axis MEMS accelerometer and a Z-axis MEMS accelerometer.

[0006] Based on the above technical solution, the present invention can also be improved as follows.

[0007] Preferably, a power module is also included, which includes a power supply and a step-down converter, which is used to convert the external input 9V~36V power supply into the 5V power supply required by the MCU processor, X-axis MEMS accelerometer, Y-axis MEMS accelerometer and Z-axis MEMS accelerometer, and is also used to convert the external input 9V~36V power supply into the 3.3V power supply required by the fiber optic gyroscope assembly.

[0008] Preferably, it also includes a satellite navigation module, which includes an anti-interference baseband integrated SoC chip, an anti-interference dual-channel RF chip and a satellite navigation receiver, which is used to connect an external satellite navigation antenna to provide GNSS positioning information for the inertial navigation system to achieve integrated navigation.

[0009] Preferably, the X-axis MEMS accelerometer and the Y-axis MEMS accelerometer are mounted perpendicularly to each other on the first hard board area, the Z-axis MEMS accelerometer and the MCU processor are mounted on the second hard board area, the first hard board area and the second hard board area are interconnected through the first soft board area line, and the first hard board area, the second hard board area and the first soft board area constitute an integrated navigation board.

[0010] Preferably, the integrated navigation board further comprises a second soft board area and a third hard board area, and the second hard board area and the third hard board area are interconnected via a line in the second soft board area; The third hard board area is provided with a power supply module and / or a satellite navigation module.

[0011] Preferably, the X-axis MEMS accelerometer, the Y-axis MEMS accelerometer and the Z-axis MEMS accelerometer are perpendicular to each other.

[0012] Preferably, the X-axis MEMS accelerometer, the Y-axis MEMS accelerometer and the Z-axis MEMS accelerometer are all connected to the MCU processor via an SPI interface.

[0013] Preferably, the fiber optic gyroscope assembly sends the gyroscope angular velocity and temperature information to the MCU processor via a TTL or RS422 serial port.

[0014] Preferably, the satellite navigation module is connected to the MCU processor via a TTL or RS422 serial port.

[0015] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: The present invention adopts a combination of a high-precision X-axis MEMS accelerometer and a fiber optic gyroscope, which can greatly reduce the volume and weight of the inertial navigation system, and reduce power consumption and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a block diagram of a fiber optic inertial navigation system based on an X-axis MEMS accelerometer of the present invention; Figure 2 This is the PCB layout diagram of the basic version of the integrated navigation board in the present invention; Figure 3 This is a schematic diagram of the installation of the basic version of the integrated navigation board in the present invention; Figure 4 This is a PCB layout diagram of an integrated navigation board including a power module and a satellite navigation module of the present invention; Figure 5 The figure is a schematic diagram of the installation of the integrated navigation board including the power module and the satellite navigation module in the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] like Figure 1 The present invention is a block diagram of a fiber optic inertial navigation system based on an X-axis MEMS accelerometer. Three mutually perpendicular MEMS accelerometers communicate with the MCU processor via an SPI interface; the fiber optic gyroscope assembly sends gyroscope angular velocity and temperature information to the MCU processor via a TTL or RS422 serial port; the power module is an optional component, used to convert an external input 9V~36V power supply into a 5V power supply required by the MCU processor, the X-axis MEMS accelerometer, the Y-axis MEMS accelerometer and the Z-axis MEMS accelerometer, and also used to convert an external input 9V~36V power supply into a 3.3V power supply required by the fiber optic gyroscope assembly, and can also be directly powered by an external independent power module; the satellite navigation module is an optional component, used to connect an external satellite navigation antenna, provide GNSS positioning information for the inertial navigation, realize combined navigation, or perform pure inertial navigation, or perform combined navigation by providing position information from an external device.

[0019] It should be noted that the X-axis MEMS accelerometer described in the present invention refers to a MEMS accelerometer whose acceleration sensitive direction is parallel to the mounting surface (printed circuit board surface), and has no direct relationship with the X-axis, Y-axis, and Z-axis in the figure.

[0020] Embodiment 1 like Figure 2 The basic version of the integrated navigation board PCB layout diagram, MEMS accelerometer 1 and MEMS accelerometer 2 are installed perpendicular to each other on the hard board area 1, the interface circuit, MEMS accelerometer 3 and MCU processor are installed on the hard board area 2, and the soft board area 1 is used for the line interconnection between the two hard board areas. It should be noted that the layout shown in the figure is only an embodiment of the present invention.

[0021] In this embodiment, the MEMS accelerometer is interconnected with the MCU processor using the SPI communication interface, the fiber optic gyroscope assembly sends the gyroscope angular velocity and temperature information to the MCU processor through the TTL or RS422 serial port, the interface circuit is used to perform RS422 and RS232 level conversion to achieve external communication, and the external power supply module supplies power to the integrated navigation board.

[0022] like Figure 3 This is the installation diagram of the basic version of the integrated navigation board. During installation, the hard board area 1 and the hard board area 2 are bent 90 degrees and installed perpendicularly to each other on an L-shaped structural member. Figure 2 From the placement directions of the three MEMS accelerometers, it can be seen that after bending, the three MEMS accelerometers are perpendicular to each other.

[0023] Embodiment 2 like Figure 4 This is the PCB layout of the integrated navigation board including the power module and the satellite navigation module. Figure 2 On the basis of the PCB, a soft board area 2 and a hard board area 3 are added, the power module and the satellite navigation module are installed on the hard board area 3, and the soft board area 1 and the soft board area 2 are used for line interconnection between the three hard board areas. It should be noted that the layout shown in the figure is only an embodiment of the present invention.

[0024] In this embodiment, the MEMS accelerometer is interconnected with the MCU processor using the SPI communication interface, the fiber optic gyroscope assembly sends the gyroscope angular velocity and temperature information to the MCU processor through the TTL or RS422 serial port, the interface circuit is used to perform RS422 and RS232 level conversion to achieve external communication, the power module is used to convert the external input 9V~36V power supply into the 5V and 3.3V power supplies required by the integrated navigation board and the fiber optic gyroscope assembly, and the satellite navigation module is used to connect the external satellite navigation antenna to provide GNSS positioning information for the inertial navigation to achieve combined navigation.

[0025] like Figure 5 This is the installation diagram of the integrated navigation board including the power module and the satellite navigation module. During installation, the hard board area 1 and the hard board area 2 are bent 90 degrees and installed perpendicularly to each other on an L-shaped structure. The hard board area 3 is bent 180 degrees and stacked on the hard board area 2. Figure 4 From the placement directions of the three MEMS accelerometers, it can be seen that after bending, the three MEMS accelerometers are perpendicular to each other.

[0026] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0027] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fiber optic inertial navigation system based on an X-axis MEMS accelerometer, characterized in that: It includes a fiber optic gyroscope component, an MCU processor, an X-axis MEMS accelerometer, a Y-axis MEMS accelerometer, and a Z-axis MEMS accelerometer.

2. The fiber optic inertial navigation system based on an X-axis MEMS accelerometer according to claim 1, characterized in that: It also includes a power module, which includes a power supply and a step-down converter for converting an externally input 9V~36V power supply into a 5V power supply required by an MCU processor, an X-axis MEMS accelerometer, a Y-axis MEMS accelerometer, and a Z-axis MEMS accelerometer, and is also used to convert an externally input 9V~36V power supply into a 3.3V power supply required by a fiber optic gyroscope component.

3. The fiber optic inertial navigation system based on X-axis MEMS accelerometer according to claim 1, characterized in that: It also includes a satellite navigation module, which includes an anti-interference baseband integrated SoC chip, an anti-interference dual-channel RF chip and a satellite navigation receiver. It is used to connect an external satellite navigation antenna to provide GNSS positioning information for the inertial navigation system and realize integrated navigation.

4. A fiber optic inertial navigation system based on an X-axis MEMS accelerometer according to any one of claim 1, characterized in that: The X-axis MEMS accelerometer and the Y-axis MEMS accelerometer are mounted perpendicularly to each other on the first hard board area, the Z-axis MEMS accelerometer and the MCU processor are mounted on the second hard board area, the first hard board area and the second hard board area are interconnected through the first soft board area circuit, and the first hard board area, the second hard board area and the first soft board area constitute an integrated navigation board.

5. The fiber optic inertial navigation system based on X-axis MEMS accelerometer according to claim 4, characterized in that: The integrated navigation board also includes a second soft board area and a third hard board area, and the second hard board area and the third hard board area are interconnected through the second soft board area line; the third hard board area is provided with a power module and / or a satellite navigation module.

6. The fiber optic inertial navigation system based on X-axis MEMS accelerometer according to claim 1, characterized in that: The X-axis MEMS accelerometer, the Y-axis MEMS accelerometer and the Z-axis MEMS accelerometer are perpendicular to each other.

7. The fiber optic inertial navigation system based on X-axis MEMS accelerometer according to claim 1, characterized in that: The X-axis MEMS accelerometer, the Y-axis MEMS accelerometer and the Z-axis MEMS accelerometer are all connected to the MCU processor via an SPI interface.

8. The fiber optic inertial navigation system based on X-axis MEMS accelerometer according to claim 1, characterized in that: The fiber optic gyroscope assembly sends the gyroscope angular velocity and temperature information to the MCU processor via a TTL or RS422 serial port.

9. The fiber optic inertial navigation system based on X-axis MEMS accelerometer according to claim 4, characterized in that: The satellite navigation module is connected to the MCU processor via a TTL or RS422 serial port.

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