Definition
inertial navigation system (English: INS) inertial navigation system is a navigation parameter solution system with a gyro and accelerometer, which is a navigation parameter solution system of sensitive devices. The navigation coordinate system is established according to the output of the gyroscope, and the speed and position of the decisor of the carrier in the navigation coordinate system is output according to the accelerometer.
Introduction
Inertial Navigation System (INS, INERTIAL NAVIGATION SYSTEM) is also known as the inertial reference system, is an exterior information, nor to external radiant energy (such as radio Navigation, the autonomous navigation system. Its work environment includes not only air, the ground, can also be underwater. The basic working principle of inertial navigation is based on the law of Newton, by measuring the gas carrier in the inertial reference system, the time is integrated, converting it into the navigation coordinate system, and can get in the navigation coordinate system. Speed, yaw angle and location and other information.
The inertial navigation system is an estimated navigation method, that is, the position of the next point is calculated from a known point according to the continuous measured moving body, and thus can continuously measure the sports body. current position. The gyroscope in the inertial navigation system is used to form a navigation coordinate system, so that the measuring axis of the accelerometer is stabilized in the coordinate system, and gives the greeque and attitude angle; the accelerometer is used to measure the acceleration of the moving body, after passing The speed is quickly obtained, and the speed can be displaced by the time of time.
Modern relatively common navigation technology, including astronomical navigation, inertial navigation, satellite navigation, radio navigation, etc., which only inertial navigation is autonomous, neither radiant in the outside, nor The stars in the sky or receiving external signals are the best.
inertial navigation is not as "unreliable", like a lot of strategies, tactical weapons, such as intercontinental flight, etc. A combination of the system and other types of navigation systems. Its cost is also relatively expensive, like a navigation level (ie 1 hour error 1 sea in the sea), at least hundreds of thousands, and this accuracy of the navigation system is enough to be equipped with aircraft like Boeing 747. Now, with the advancement of MEMS (microelectronic mechanical system) inertial device technology, business grade, consumer-level inertial navigation gradually enters the home of ordinary people.
Advantages
The inertial navigation system has the following Advantages : 1, because it does not rely on any external information, no self-radiant energy System, so hidden hidden, not affected by external electromagnetic interference; 2. All-day, full-time work in air, earth surface and even underwater; 3, can provide position, speed, heading and posture corner data, resulting The navigation information is continuous and the noise is low; 4, the data update rate is high, the short-term accuracy and stability are good.
Disadvantages
It Disadvantages Yes: 1, due to the integration of navigation information, the positioning error increases over time, long-term accuracy; 2, Require long initial alignment time each time you use; 3. The price of the device is more expensive; 4, the time information cannot be given.
However, a fixed drift rate is convolved, which causes the error of the object motion, so the weapon of the range is usually corrected to the inertiality of the intention, GPS, etc. to obtain continuous and accurate positional parameters. . The inertial system has now developed a variety of ways of flexible inertiality, fiber optic inertiality, laser inertiality, and micro-solid inertial instrumentation. The gyroscope is developed by traditional winding gyro to electrostatic gyro, laser gyro, fiber optic gyro, micromechanical gyro, etc. The laser gyro measurement has a wide range of dynamic range, good linearity, stable performance, and has good temperature stability and repetition, which has always dominated in high-precision applications. Due to scientific and technological progress, the lower cost of fiber optic gyro (FOG) and micromechanical gyro (MEMS) is getting higher and higher, is the direction of future gyro technology.
Classification
1. Piente inertial navigation system
2. Analytical inertial navigation system
3. Semi-analytical inertia Navigation System
Apply
The inertial navigation system is used in various motors, including aircraft, submarine, space shuttle and other transportation tools and missiles, but cost and complexity limit it. Application occasion.
The inertial system is first applied to the Rocket Guidance, and the American Rocket Pioneer Robert Gordalt GotDard tries its early gyro system. During the Second World War, the German Feng Brun improved, it was applied to the V-2 rocket guidance. After the war, the US Massachusetts Institutes and other research institutions and personnel conducted in-depth research on inertial guidance, thereby developing a modern inertia navigation system for the application aircraft, rocket, space shuttle and submarine.
Importance
inertial technology is one of the key technologies for navigating the carrier, inertial technology is a technique for using inertial principles or other related principles, autonomous measurement and controlling carrier motion It is a general name of inertial navigation, inertial guidance, inertial measurement and inertial sensitive techniques. With the support of the strong funds of governments, modern inertia technology has penetrated into the civilian field from the initial military application. Inertial technology has a very important status in defense equipment technology. For medium and long-range missiles for inertial guidance, the precision is 70% of the precision of the guidance system depends on the accuracy of the guidance system. For the missile nuclear submarine, due to the long time, its position and speed are changed, and these data is the initial parameters of the launch missile, directly affect the hit accuracy of the missile, and require high-precision position, speed, and vertical alignment signal. The only navigation device currently applied to the submarine is the inertial navigation system. The inertial navigation is completely navigated independently of the carrier itself, does not rely on external information, has a good concealment, and work is not affected by meteorological conditions and human interference, and is highly accurate. For remote cruise missiles, inertial guidance systems plus map matching techniques or other guidance techniques, ensuring that it can hit the target with a high precision after thousands of kilometers. Inertial technology is gradually promoted to aerospace, aviation, navigation, oil development, earth measurement, marine survey, geological drilling control, robot technology and railway, etc. With the emergence of new inertial sensitive devices, inertial technology in automotive industry, medical electronics Applications are obtained in the equipment. Therefore, inertial techniques are not only a very important status in defense modernization, but also increasing its huge role in all areas of the national economy.
Development
The inertial system is a self-stairs estimate of the active position, position and speed of the carrier, using the inertial sensor, the reference direction and the initial location information to determine the orientation of the carrier. It should at least consist of an inertial measuring device, a digital computer, and a control display device and a dedicated precision power source. The movement of the carrier is carried out in three-dimensional space, its movement form, one is the line movement, one is angular movement. Regardless of line sports or corner, it is three-dimensional space. It is necessary to establish a three-dimensional inertia platform. With a three-axis inertia platform, it can provide a reference to measure the acceleration of three free line acceleration. The three line acceleration components of each known orientation was measured. The motion vectors of the carrier were calculated through the computer, so the first large class inertial system solution was a platform-type inertial navigation system. Without a "electromechanical" platform, install the inertial component gyroscope and accelerometer directly on the carrier, establish a "mathematical" platform in the computer, to obtain the speed and position of the carrier by complex computing and transformation, this unmecting platform The inertial system is the second largest type of inertial system solution, called a Jiechang Inertial Monitor.
From the general sense, the process of guiding the navigation carrier to the destination from the starting point is called navigation. From a narrow, navigation is a technical and method for providing real-time posture, speed, and location information to a navigation carrier. Early people relied on the geometrics, starlight, solar height, etc., geographic approach acquisition, targeted information, with the development of science and technology, radio navigation, inertial navigation and satellite navigation and other technologies, are widely used in military, civil and other fields. Among them, inertial navigation is a technical method of using a gyroscope and accelerometer loaded on the carrier and an accelerometer to measure the carrier attitude, speed, location and other information. The softness of the inertial navigation is achieved, the hardware device is called the inertial navigation system , referred to as the inertial system.
Pientel inertial navigation system (Strap-Down Inertial Navigation System, Short SINS) is installed directly on the carrier in the computer in a computer in real time to calculate attitude towards the carrier in the computer The matrix is calculated to calculate the relationship between the carrier coordinate system and the navigation coordinate system, thereby converting the accelerometer information of the carrier coordinate system into information under the navigation coordinate system, and then performs navigation calculations. Since it has the advantages of high reliability, strong weight, light weight, low cost, high precision, etc., so that Sins has become the mainstream of today's inertial navigation system development. The NETIAL MEASUREMENT UNIT, the INERTIAL MEASUREMENT Unit, and the IMU are the core components of the inertial system. The accuracy of the IMU's output information determines the accuracy of the system.
gyroscope and accelerometer are indispensable core measuring devices in the inertial navigation system . Modern high-precision inertial navigation system proposed high requirements for the gyroscope and accelerometers used, because the gravizular drift error and accelerometer zero bias is affecting the accuracy of the inertians The most direct and most important factors, so how to improve the performance of the inertial device, improve the measurement accuracy of the inertial components, especially the gyroscope measurement accuracy, has always been the focus of the inertial navigation field. The development of the gyroscope has experienced several stages. The initial ball bearing gyro, its drift rate is (L-2) ° / h, the gas float, liquid floes and magnetic floset developed by overcome the inertial instrument support technology, and its accuracy can reach 0.001 ° / h, The electrostatic support gyro is preferably from 0.0001 ° / h. Since the 1960s, the development of flexible gyro begins to start, and its drift accuracy is better than 0.05 ° / H, the best level can reach 0.001 ° / h.
In 1960, the laser gyro first developed successfully, marking the optical gyro started to dominate the gyro market. At present, the zero-nip stability of the laser gyro can be up to 0.0005 ° / h. The biggest problem facing the laser gyro is that the manufacturing process is more complicated, and there is a high cost, and the volume and weight are also large. This is a certain degree The development application in certain areas is limited, and on the other hand, the laser gyro is developed to low cost, miniaturization, and three-axis integral direction. Another optical gyro-fiber gyro not only has many advantages of laser gyro, but also has the characteristics of simple manufacturing process, low cost and light weight, and is currently the fastest optical gyro
my country's development
my country's inertial technology has achieved long progress, Liquid Furura platform inertial navigation system, and the power tuning gyro four-axis platform system has been applied to the Long March series launch rocket. Other various types of small-scale conjunction, fiber optic gyro-guided, laser gyro-guidelines, and matching GPS correction, etc. have also been largely applied to tactical guidance weapons, aircraft, ship, launch rocket, spaceship, etc. Such as drift rate 0.01 ° ~ 0.02 ° / h in the new fighter test flight, the drift rate of 0.05 ° / h below the fiber optic gyro, the application of Jieli is inertially in the ship, the application on the submarine, as well as small The application of Several Inertial Guidelines in various types of missile guidance weapons has greatly improved the performance of our military equipment.