Method for determining a change in the range of a lidar sensor for a vehicle or a robot, characterized in that in a reference measurement having a reference target located at a predetermined distance (d_0) from the lidar sensor - a reference noise level (R_0) of infrared radiation received by the lidar sensor and - a signal-to-noise ratio (SNR_0) of infrared radiation reflected at the reference target and received by the lidar sensor are determined, in a driving operation measurement during a driving operation of the vehicle or robot - a current noise level (R_1, R_2) of infrared radiation received by the lidar sensor is determined, - a value of an intensity (I_1, I_2) of the infrared radiation is determined by multiplying the determined current noise level (R_1, R_2) by the signal-to-noise ratio (SNR_0) determined in the reference measurement, and - from the determined value of the intensity (I_1, I_2) of the infrared radiation and a known path-dependent attenuation of the infrared radiation, a theoretical distance (d_1, d_2) to a position (P_1, P_2) at which the reference target would have to be located if the same signal-to-noise ratio as in the reference measurement is present at the current noise level (R_1, R_2) is determined, and in a range change calculation, a deviation between the predetermined distance (d_0) and the theoretical distance (d_1, d_2) is determined, the deviation corresponding to the change in the range of the lidar sensor compared to the range of said sensor during the reference measurement. in a reference measurement having a reference target located at a predetermined distance (d_0) from the lidar sensor - a reference noise level (R_0) of infrared radiation received by the lidar sensor and - a signal-to-noise ratio (SNR_0) of infrared radiation reflected at the reference target and received by the lidar sensor - a reference noise level (R_0) of infrared radiation received by the lidar sensor and - a signal-to-noise ratio (SNR_0) of infrared radiation reflected at the reference target and received by the lidar sensor are determined, in a driving operation measurement during a driving operation of the vehicle or robot - a current noise level (R_1, R_2) of infrared radiation received by the lidar sensor is determined, - a value of an intensity (I_1, I_2) of the infrared radiation is determined by multiplying the determined current noise level (R_1, R_2) by the signal-to-noise ratio (SNR_0) determined in the reference measurement, and - from the determined value of the intensity (I_1, I_2) of the infrared radiation and a known path-dependent attenuation of the infrared radiation, a theoretical distance (d_1, d_2) to a position (P_1, P_2) at which the reference target would have to be located if the same signal-to-noise ratio as in the reference measurement is present at the current noise level (R_1, R_2) is determined, and - a current noise level (R_1, R_2) of infrared radiation received by the lidar sensor is determined, - a value of an intensity (I_1, I_2) of the infrared radiation is determined by multiplying the determined current noise level (R_1, R_2) by the signal-to-noise ratio (SNR_0) determined in the reference measurement, and - from the determined value of the intensity (I_1, I_2) of the infrared radiation and a known path-dependent attenuation of the infrared radiation, a theoretical distance (d_1, d_2) to a position (P_1, P_2) at which the reference target would have to be located if the same signal-to-noise ratio as in the reference measurement is present at the current noise level (R_1, R_2) is determined, and in a range change calculation, a deviation between the predetermined distance (d_0) and the theoretical distance (d_1, d_2) is determined, the deviation corresponding to the change in the range of the lidar sensor compared to the range of said sensor during the reference measurement.