GNSS monitoring has become widespread in transport, significantly increasing the efficiency of its use. Moreover, the data received through communication channels, as a rule, is stored by online services and can be further used to solve a variety of tasks. Monitoring service providers provide an opportunity for users to freely upload reports generated on the basis of monitoring. However, the use of this data comes with a number of limitations. First of all, this is due to errors in determining the current speed of the car, which is due to the peculiarities of satellite navigation technology. Therefore, monitoring data are subject to preliminary processing in order to exclude or correct anomalous observations caused by measurement error. The portable application "Stamm" presented in the article contains tools for smoothing incorrect measurements.