Array type double-shaft rotating inertial navigation system

Abstract

The utility model relates to an array type double-shaft rotating inertial navigation system. A plurality of micro-electro-mechanical inertial measurement units are used for constructing an inertial measurement array in an array form, the inertial measurement array is mounted in a double-shaft indexing mechanism, and a main control module is configured for rotation control and navigation calculation, so that the array type double-shaft rotation inertial navigation system is formed. The inertial measurement array in the system performs data fusion through redundant inertial measurement information, and suppresses random errors of the system; meanwhile, the system controls the double-shaft indexing mechanism to regularly rotate, so that constant errors such as zero offset, scale factor error and installation error of the inertial measurement array periodically and alternately change positively and negatively in navigation calculation, and online compensation of the constant errors is realized. According to the utility model, the random error in the inertial navigation system is effectively inhibited, and the constant error is compensated, so that the navigation precision of the system is obviously improved. The utility model belongs to the technical field of inertial navigation and can be applied to carrier autonomous navigation.

Description

Technical Field

[0001] The utility model relates to an array type dual-axis rotating inertial navigation system, which is suitable for occasions of carrier autonomous navigation. Technical Background

[0002] The inertial measurement array originated from the concept of "array gyroscope" proposed by Bayard et al. in 2003 (Bayard DS. Combining multiple gyroscope outputs for increased accuracy [R]. Pasadena: NASA's Jet Propulsion Laboratory, 2003.), which combines multiple chip-level micro-electromechanical (MEMS) inertial measurement units (IMU) into an array. Through data fusion, its random errors can be greatly suppressed and navigation accuracy can be improved. MEMSIMU has the technical capability of mass production, and its application scale in the consumer field is huge. It can be produced on a large scale at low cost. It is expected to build a low-cost and high-precision inertial navigation system based on array technology.

[0003] At present, the research on inertial measurement arrays mainly focuses on the optimization of random errors. In inertial navigation systems, compensation of constant errors such as zero bias, scale factor error, and installation error is also extremely important. The compensation of constant errors of inertial measurement arrays is generally performed by offline calibration. However, the poor repeatability and long-term slow variation of the array constant error make it difficult for the inertial measurement array using offline calibration to meet the performance requirements of inertial navigation in related industries. Therefore, online compensation of inertial measurement arrays is imperative, but there are no relevant research reports on online compensation of constant errors of inertial measurement arrays. In high-precision single-body IMUs, rotation modulation technology is an online error compensation method that has been used for a long time. Rotation modulation technology drives the IMU to rotate periodically, so that the constant error in the direction orthogonal to the rotation axis is modulated into a periodic variation form with a full cycle integral of zero. After navigation integration, self-compensation of the constant error can be achieved, thereby improving the accuracy of inertial navigation.

[0004] Therefore, how to compensate for its constant error online and significantly improve the navigation accuracy of the MEMS inertial navigation system is of great significance to the low cost of high-precision inertial navigation systems. Utility Model Content

[0005] The technical problem solved by the utility model is to compensate the zero bias, scale factor error and installation error of the IMU online, thereby greatly improving the navigation accuracy of the inertial navigation system.

[0006] The technical solution of this utility model:

[0007] An array-type dual-axis rotating inertial navigation system includes an inertial measurement array, a dual-axis indexing mechanism and a main control module. The system has the ability to suppress IMU random errors and online compensate for IMU zero bias, scale factor error and installation error. The system outputs high-precision position, speed and attitude.

[0008] An inertial measurement array is composed of 96 MEMS IMUs, which are mounted on one side of a printed circuit board in a 4×4 array structure. It is double-sided mounted and one printed circuit board contains 32 MEMS IMUs. Three printed circuit boards with the same structure are stacked and installed. The 96 sets of data output by the inertial measurement array are fused to suppress the random error of IMU.

[0009] The inertial measurement array is installed in a dual-axis indexing mechanism. During navigation, the indexing mechanism is controlled to rotate regularly to compensate for IMU zero bias, scale factor error and installation error online. The dual-axis indexing mechanism consists of two frames, the outer frame axis coincides with the heading axis of the carrier, and controls the rotation of the heading direction of the inertial measurement array. The inner frame axis coincides with the pitch axis of the inertial measurement array, and controls the rotation of the pitch direction of the inertial measurement array. The dual-axis indexing mechanism has the function of receiving control angle instructions and controlling the angle in real time.

[0010] The inertial measurement array is installed in the inner frame of the dual-axis indexing mechanism, and the dual-axis rotation mechanism and the main control module are fixedly connected to the system base. The main control module has a DC wide voltage input capability of 9 to 36V, provides 5V DC power supply for the inertial measurement array and indexing mechanism, collects the inertial measurement data output by the inertial measurement array through the RS422 interface, controls the indexing mechanism to rotate through the RS422 interface, calculates the system position, speed and array attitude based on the collected inertial measurement data, performs attitude decoding and calculates the system attitude based on the array attitude and the real-time angle of the indexing mechanism, and outputs the system position, speed and attitude through the RS422 interface.

[0011] Compared with the existing solutions, the main advantages of the solution of the utility model are: the existing solutions only use an array form to suppress the random error of the IMU, and cannot compensate for the constant error online, and the improvement of the system accuracy is limited; the solution of the utility model can not only suppress the random error, but also compensate for the constant error online through dual-axis rotation, thereby realizing the parallel optimization of random error and constant error, and greatly improving the navigation accuracy of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Specific implementation plan diagram; Specific implementation plan

[0013] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0014] The specific implementation scheme of the utility model is as follows Figure 1 As shown, the specific implementation steps are as follows:

[0015] (1) 96 MEMSIMUs are used to form an inertial measurement array, in which a 4×4 array structure is mounted on one side of a printed circuit board, with double-sided mounting. One printed circuit board contains 32 MEMSIMUs, and three printed circuit boards with the same structure are stacked and installed. FPGA is used as the main controller to collect IMU data. The array is powered by a 5V DC power supply and outputs the three-axis angular rate, acceleration, and IMU temperature of each IMU through RS422.

[0016] (2) Two inner and outer frames are orthogonally installed to form a dual-axis indexing mechanism. The outer frame axis coincides with the heading axis of the carrier to control the rotation of the inertial measurement array in the heading direction. The inner frame axis coincides with the pitch axis of the inertial measurement array to control the rotation of the inertial measurement array in the pitch direction. The indexing mechanism includes a 10-core conductive slip ring, a motor, a grating code disk and a main controller. The main controller is a single-chip microcomputer architecture. It establishes external communication through the RS422 interface. After receiving the angle control command, it controls the motor to rotate to the specified angle and collects the grating code disk angle measurement information for output feedback.

[0017] (3) The main control module is constructed with FPGA+DSP architecture. FPGA is responsible for communication with the inertial measurement array, dual-axis indexing mechanism and external cross-linking equipment, and DSP is responsible for strapdown navigation solution, attitude demodulation and indexing scheme execution. It uses 9-36V DC wide voltage input. The main control module collects data output by the inertial measurement array based on FPGA, issues control instructions to the dual-axis indexing mechanism and collects feedback, and outputs the system position, speed and attitude to the outside; based on DSP, the collected inertial measurement array data is fused to suppress IMU random errors, and then strapdown navigation solution is performed to output the array position, speed and attitude; based on DSP, the preset dual-axis indexing scheme is executed to control the regular rotation of the inner and outer frames of the dual-axis indexing mechanism, and online compensation is performed for IMU zero bias, scale factor error and installation error; based on DSP, attitude demodulation is performed based on the collected dual-axis indexing mechanism inner and outer frame angle measurement information and the solved array position, speed and attitude, and the system position, speed and attitude are output.

[0018] (4) Install the inertial measurement array in the inner frame of the dual-axis indexing mechanism, and connect the power line and RS422 communication line to the corresponding core line of the main control module through a conductive slip ring. The dual-axis indexing mechanism and the main control module are fixedly installed on the system base, and the dual-axis indexing mechanism power line and RS422 communication line are connected to the corresponding core line of the main control module. The main control module input power line and the external RS422 interface line are connected to the aviation socket of the system shell to connect the system to the external cross-linking equipment and realize the normal operation of the system.

[0019] The utility model combines MEMSIMUs in an array to perform data fusion to suppress random errors, controls the array to rotate regularly through a dual-axis indexing mechanism to compensate for constant errors online, and after dual optimization of random errors and constant errors, the navigation accuracy of the inertial navigation system can be greatly improved on the basis of controlling costs.

[0020] The contents not described in detail in this utility model belong to the prior art known to professional and technical personnel in this field.

Claims

1. An array-type dual-axis rotating inertial navigation system, characterized in that: The system consists of 96 micro-electromechanical inertial measurement units, a two-axis indexing mechanism, and a main control module; The micro-electromechanical inertial measurement unit is mounted on a printed circuit board to form an inertial measurement array; The dual-axis transfer mechanism includes two frames, an inner and outer frame, and the inertial measurement array is installed in the inner frame of the dual-axis transfer mechanism; the outer frame axis coincides with the carrier heading axis, which is used to control the rotation of the inertial measurement array in the heading direction; the inner frame axis coincides with the inertial measurement array pitch axis, which is used to control the rotation of the inertial measurement array in the pitch direction. The dual-axis transfer mechanism can receive control angle instructions to control the angle in real time; The main control module is fixedly connected to the system base together with the dual-axis transfer mechanism. The main control module is responsible for powering the inertial measurement array and the dual-axis transfer mechanism, collecting the output data of the inertial measurement array, and controlling the regular rotation of the dual-axis transfer mechanism.

2. The array-type dual-axis rotating inertial navigation system according to claim 1, characterized in that: The inertial measurement array is composed of 96 micro-electromechanical inertial measurement units, which are mounted on one side of a printed circuit board in a 4×4 array structure. It is double-sided mounted. One printed circuit board contains 32 micro-electromechanical inertial measurement units. Three printed circuit boards with the same structure are stacked and installed to form an array containing 96 micro-electromechanical inertial measurement units.

3. The array-type dual-axis rotating inertial navigation system according to claim 1, characterized in that: The main control module has a 9-36V DC wide voltage input capability, provides 5V DC power supply for the inertial measurement array and the transfer mechanism, collects the inertial measurement data output by the inertial measurement array through the RS422 interface, controls the transfer mechanism to rotate through the RS422 interface, and outputs the position, speed and attitude of the system through the RS422 interface.

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