According to the distance error and Angle error of landmark observation, the AGV is judged to be subject to external interference.Is the square of the distance difference between the predicted value and the observed value, which is normalized as:(53) 5 -In the formula, Sm is the Jacobian matrix of the observation function about the landmark position.N(0,1) is normally distributed.When the value is greater than 2.3, that is, when a small probability event occurs, it means that the observation of the channel has a large possibility of error due to the influence of external interference.The threshold value is set according to the number of observation landmarks, control and observation error covariance matrix. When the number of landmarks with large observation error exceeds the threshold value, the AGV is determined to be subject to external interference.The error of steering Angle is an important factor that leads to the inconsistencies in the prediction of SLAM algorithm, and the greater the error, the lower the prediction accuracy of SLAM.Is the square of the angular difference between the predicted value and the observed value, which is normalized as: