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Inertial Navigation Error

Sep 11, 2019

Error accumulation of inertial navigation

Because the new position information is calculated based on the previously calculated position information and the measured acceleration and angular velocity, the accumulated error is roughly proportional to the time from when we input the initial position.


Precision control of inertial navigation

High quality navigation systems typically have inaccuracies that are less than 0.6 nautical miles per hour in position and less than a few tenths of an hour in the direction. If the navigation system fails, the aircraft can still be made without deviating from the track.

  

Therefore, inertial navigation is often used to support other navigation systems, providing greater accuracy than using any single system. For example, when applied to the surface plane, if the object stops, the inertial tracking speed is intermittently updated to zero, and this position will remain accurate for a longer period of time, which is called zero speed update. Especially in the aerospace field, other measurement systems are used to determine the inertial navigation system (INS) errors, such as the Honeywell LaseRefV inertial navigation system using GPS and atmospheric data computer output to maintain the desired performance of navigation.


Navigation errors increase with the use of low sensitivity sensors. Currently, devices are being developed in conjunction with different sensors, such as the Attitude Reference System. Since the main influencing factor of navigation error is the numerical integration of angular velocity and acceleration, the pressure reference system was developed to measure the angular velocity using numerical integration.


Method for solving inertial navigation system error

Usually the estimation theory (especially Kalman filtering) provides a theoretical framework that combines information from different sensors. The most common alternative sensor is a satellite navigation broadcast (eg, GPS can be used for various ground vehicles when direct visibility is high). Indoor applications can use pedometers, distance measuring devices, or other types of position sensors. By properly merging the information of the inertial navigation system (INS) with other systems (GPS / INS), the position and velocity of the error can be stabilized. Furthermore, the inertial navigation system (INS) can be used as a temporary feedback when GPS signals are not available (eg, when the vehicle passes through a tunnel).

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