M-0.5 Attitude and Heading Reference System, a high-performance MEMS-based solution for precise attitude measurement. This advanced system utilizes state-of-the-art MEMS sensors and incorporates accurate error calibration and compensation techniques to ensure exceptional performance. With a fast start-up time of just 3 minutes, it provides reliable measurements of 3D attitude, angular rate, and acceleration. The M-0.5 system offers an impressive attitude accuracy of 0.05 degrees (1σ) and heading accuracy of 2 times the secant of latitude (1σ). Its rugged design and stringent fabrication processes guarantee reliability and environmental suitability. Enhance your carrier's capabilities with the M-0.5 Attitude and Heading Reference System, suitable for a wide range of applications in UAVs, unmanned vehicles, guided munitions, and more. Trust in its precision and dependability for optimal performance in challenging environments.
Features
1.Cost‐effective MEMS Gyroscope and Accelerometer
2.Full scale temperature compensation
3.Good anti‐vibration and anti‐shock performance
4.Excellent environmental suitability
Applications
1.Navigation and control for land vehicle
2.Antenna stabilization and control
3.Navigation and control for industrial UAV
4.Attitude and heading reference
5.Tactical missile guidance and control
6.Heading and attitude reference for under water vehicle
PERFORMANCE INDEX
1、High precision MEMS navigation system interface
1.With the function of transmitting position information, attitude information, north direction information, time code information, angular rate and speed, etc. to the data processing combination through 1 RS-422 standard serial port;
2.With the function of transmitting position information, attitude information, north direction information, time code information, angular rate and speed, etc. to the data processing combination via 1 channel Ethernet;
3.Having the function of transmitting second pulse signal to the control combination via 1-way IF SMA interface;
4.The function of sending 10 MHz clock signal to the control combination with 1 IF SMA interface;
5.Ethernet and serial port communication cycle of 500Hz;
6.The debugging interface is reserved at the front panel.
The electrical interfaces are summarized as follows:
Serial and Ethernet interface (XS5)
Communication protocols
1、422 serial port
1.Communication rate
Adopt asynchronous serial standard full duplex RS422 electrical interface standard.
Baud rate: 1Mbps by default, hardware should support 1Mbps.
2.Communication frame format
Each frame contains 10 bits in the following order
Start bit: 1 bit;
Data bits: 8 bits (send the low bit first and then the high bit);
Stop bit: 1 bit.
3.Communication message format
The communication message consists of several frames (bytes), and the header is sent first, then the data bits, and finally the check and end bits. Bytes are transmitted in the order of "byte 0" to "byte n+2", with each byte sending the low bit first and then the high bit. A complete communication consists of a "control message" sent at the same time as the analog extension, followed by a "return message" from the receiver.
Table 6 RS442 serial communication message format
Data bits - The high-precision MEMS navigation system receives the following telegrams:
High precision MEMS navigation system receiving telegrams
The data bit-high precision MEMS navigation system returns the following telegrams:
High precision MEMS navigation system reply message
2、Ethernet
High-precision MEMS navigation system reports back Ethernet telegram messages
High precision MEMS external connector debug line
(J30JZ-25TJL)
Cable length 1500mm,Cable: 0.15 square twisted pair
General idea
The high precision MEMS navigation system mainly consists of the structure, hardware circuit and system software. The workflow of the system is shown in Figure 1.
High precision MEMS navigation system navigation system workflow diagram
Structural solutions
The high precision MEMS navigation system mainly consists of inertial measurement components, interface expansion board, dual antenna guard card, secondary power supply, B-code terminal, 2U chassis, connectors and other components, as shown in the figure below.
MEMS navigation system composition
1、Inertial measurement component structure
The inertial assembly consists of housing, base plate, IMU, connector and other components, and the specific structural form and appearance are shown in the figure below.
2、IMU structure
The gyro and accelerometer on the IMU of the high-precision MEMS system are arranged in an orthogonal mounting on the table. The gyro and accelerometer are soldered on the PCB board, and then the PCB board with the gyro and accelerometer soldered on it is orthogonally mounted through the mounting block, and the mounting reference block provides the mounting reference for the gyro and accelerometer. The ARM chip and power supply chip are arranged on the Z gyro PCB board to meet the system reliability and maintainability requirements while being as small as possible, and the IMU is connected to the equipment case through four mounting holes on the Z gyro PCB board.
System hardware solutions
1、Hardware Block Diagram
Hardware Block Diagram
2 、Circuit schematic
Core section circuit schematic
Navigation system software solutions
1、 Navigation system algorithm structure
The algorithm of MEMS inertial unit IMU for navigation calculation uses SINS shortcut inertial navigation algorithm, SINS shortcut inertial navigation algorithm can provide all the navigation information by 6 degrees of freedom navigation solution, which is the ideal algorithm for MEMS personal navigation. The navigation and correction algorithm, the structure of the algorithm is shown in Fig. l. By designing the stationary detection and improved Kalman filter algorithm, the zero velocity correction is effectively achieved, which can largely improve the navigation and positioning accuracy.
General framework of the software
2、General framework of the software
2.1 、Coordinate system definition
Inertial navigation is based on the precise definition of a series of Cartesian reference coordinate systems, each of which is a right-handed orthogonal coordinate system. A total of eight coordinate systems are defined: inertial coordinate system (i-system), earth coordinate system (e-system), geographic coordinate system (t-system), carrier coordinate system (b-system), initial moment inertial coordinate system (i0-system), initial moment earth coordinate system (e0-system), initial moment navigation coordinate system (n0-system), and initial moment solidified inertial coordinate system (ib0-system).
Coordinate system definition
2.5、Initial Alignment Algorithm
2.51、Coarse Alignment Algorithm
The fine alignment of an inertial guidance system must be performed on the basis of coarse alignment. The general coarse alignment method is to calculate the attitude matrix of the base based on accelerometer measurements of gravitational acceleration and gyroscope measurements of the angular velocity of Earth rotation, but this is only applicable to alignment environments with little disturbance. For the alignment environment in which the ship is at mooring or the ship is in a uniform direct flight, the signal-to-noise ratio in the gyro output is very low because the external disturbance angular velocity is much larger than the earth rotation angular velocity, and it is no longer possible to achieve the coarse alignment of the inertial guidance system by the ordinary coarse alignment method. This solution achieves coarse alignment of the inertial guidance system under the disturbed base by measuring the gravity integral.
Coarse alignment principle based on gravity integration measuremen
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