The earliest gyroscopes are all mechanical, and there are really high-speed rotating gyroscopes in them, and mechanical things have high requirements for processing accuracy, and they are also afraid of vibration, so the accuracy of mechanical gyroscope-based navigation systems has not been high. As a result, people began to look for better ways to use advances in physics to develop laser gyroscopes, fiber optic gyroscopes, and micro-electromechanical gyroscopes (MEMS). Although these things are still called gyroscopes, their principles are completely different from traditional mechanical gyroscopes.
Fiber optic gyroscopes use the Sagnac effect to measure the optical path difference to calculate the angular velocity of rotation through the characteristics of light propagation.
The laser gyroscope also calculates the angular velocity by calculating the optical path difference, instead of the gyroscope.
Micro-electromechanical gyroscopes use the Coriolis force of physics to generate tiny capacitance changes inside, and then measure the capacitance to calculate the angular velocity to replace the gyroscope. The gyroscopes used in iPhones and our smartphones are microelectromechanical gyroscopes (MEMS).
At present, traditional mechanical gyroscopes are being phased out, and laser gyroscopes are used where high precision is required. Originally, gyroscopes are tall, but because of the emergence of microelectromechanical gyroscopes (MEMS), low-cost gyroscopes can be used in many fields. In addition to the familiar smartphones, many MEMS gyroscopes are also used in automobiles. In high-end automobiles, about 25 to 40 MEMS sensors are used to detect the working status of different parts of the automobile and provide information to the on-board computer. The user has better control over the car.
Several methods of high-precision north finding at present
1.Static North Finder (North Finder, Gyro North Finder or Fiber Optic Gyro North Finder)
1.1 North Finder (Gyro North Finder)
Principle: The rotation axis of the gyroscope keeps its orientation unchanged relative to the inertial space, and the earth rotates relative to the inertial space around the polar axis with its rotation angular velocity. If the earth is used as a reference, the rotation axis of the gyroscope will be seen to rotate relative to the earth. The instrument can track and measure the angular velocity of the earth's rotation.
Composition: It is composed of a two-degree-of-freedom dynamic tuning gyro, a mechanical rotating device and a signal solving circuit.
Case: ERICCO's MEMS ER-MG2-100 is used in vehicle directional shaping applications, directional drilling, etc.
North finding accuracy: 0.06 degrees
Principle: The fiber optic gyro north finder is mainly used to quickly and autonomously determine the true north direction. The earth's rotation angular velocity is obtained through high-precision fiber optic gyroscope tracking, and the earth's rotation angular velocity signal is decomposed and solved to calculate the angle between the main axis of the gyroscope and the true north direction of the earth, and provide azimuth information for the carrier.
Composition: The fiber optic gyroscope north finder is a mechatronic product, which consists of a fiber optic gyroscope, an accelerometer, a mechanical rotation control device and an embedded computer.
2.Dynamic north finding (fiber optic gyro compass)
2.1 Fiber Optic Gyro Compass (Vehicle, Ship, Airborne)
Principle: Use the strapdown compass effect to solve the true north direction.
Composition: three-axis dynamic gyro, three-axis acceleration sensor, data acquisition and processing module, secondary power supply, optocoupler isolation input and output serial port circuit, and other related structural components.
Operation: After power on, the product enters the preheating time, and after the preheating time, the product switches to the initial self-alignment under the condition of the moving base. 30 minutes after the product is powered on, the carrier carrying the product can be running. During operation, the product will timely output the heading angle, roll angle and pitch angle.
Case: ERICCO's FOG ER-FOG-910 is used in drilling, mining, and surveying.
North finding accuracy: 0.02º/h
3.GPS or Beidou North Finding (Dual Antenna Direction Finding)
Principle: Using the high-precision two-dimensional attitude information obtained by processing the baseline distance between the GPS main antenna and the second antenna, it can calculate the pitch or roll, heading and other data of the carrier in real time, and the fastest can reach 10 times per second.
More Technical Questions
1.The Principle and Application of North Finder
3.Price Analysis and Application Introduction of North Seeker
4.Application of North Finder in Mining Industry
5.Do You Know the FOG North Finder?
6.Do You Know Fiber Optic Gyroscope and Its Typical Applications?
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