Due to the complex and changeable working environment, the motion parameters of the cross-domain vehicle are greatly affected by transient impacts during the flight process, which leads to the reduction of navigation accuracy and difficulty in stable control. Aiming at the problem of transient impacts that make it difficult to obtain accurate motion parameters of the cross-domain vehicle, an inertial navigation device based on the combination of large and small-range accelerometers is developed, and a switching strategy of large and small-range accelerometers is proposed, which utilizes the Butterworth filter to filter the collected data, and realizes the detection of the impact point through the accumulation of preset thresholds and control chart algorithms and an autonomous variable sliding window, and adopts a segmented linear interpolation method to ensure the data synchronization. Segmented linear interpolation method ensures the synchronization of the data. Finally, the switching strategy proposed in this paper is experimentally verified by simulation and drop table test, and the test results show that the estimation error of the segmented linear interpolation method is no more than 0.6g, and it switches to the measured value of the large-range accel-erometer after the small-range accelerometer measurement value is saturated to satisfy the requirement of real-time switching, which further proves that this inertial navigation This further proves that the inertial navigation device and the small- and large-range switching strategy can be applied to the cross-domain vehicle for cross-domain experiments.