The strapdown inertial navigation system is independent of external information and is not easily disturbed by interference. It is an autonomous navigation system. Compared to the platform inertial navigation system, the strapdown has saved the inertial platform, and the volume and weight of the system are greatly reduced, and it is also convenient to maintain. However, the gyroscopes and accelerometers directly bear the vibration, impact and angular motion of the aircraft, thus generating dynamic errors. This is a higher requirement for gyroscopes and accelerometers.
The strapdown inertial navigation system with gyroscope according to different can be divided into two categories: one is the rate gyroscope, such as single degree of freedom flexible gyroscope, laser gyro, it is measured by the angular velocity of the aircraft; one is the double degree of freedom gyroscope, such as electrostatic gyro instrument is measured the angular displacement of aircraft. What we usually say is the rate strapdown inertial navigation system.
The most important feature of strapdown inertial navigation system is to rely on navigation coordinate system, which has simple structure, small volume, light weight, low cost, simple maintenance and high reliability. Attitude updating is the key algorithm of strapdown inertial navigation.