Compensation method and device for random constant error of inertial device of integrated navigation system

The invention discloses a method and a device for compensating random constant errors of an inertial device of an integrated navigation system. The method comprises the following steps: acquiring an actual size of a lever arm between an inertial measurement unit (IMU) and a GPS antenna in the integrated navigation system; a Kalman filter is constructed; if a preset condition is met, respectively compensating the inertial device random constant error a to an angle increment output by a gyroscope of the integrated navigation system and a speed increment output by an accelerometer, and compensating the lever arm error estimation value b to a lever arm size from an IMU (Inertial Measurement Unit) to a GPS (Global Positioning System) of the integrated navigation system; otherwise, estimating the error state vector by a Kalman filter, and updating the random constant error a of the inertial device and the estimated value b of the lever arm based on the estimated error state vector. According to the method, the prec