Abstract: The present disclosure generally relates to a method for testing a telecommunication standard-based positioning, navigation, and timing system and a test device. The system includes the test device. Radio signals from at least three different transmitters are received by the test device. Each transmitter transmits a radio signal according to the telecommunication standard. An assessed position of the test device is determined based on the radio signals received by the test device. The position of the mobile device is determined by the test device additionally to the assessed position. The assessed position is compared with the determined position.

Abstract: A method of training an artificial intelligence circuit is provided. The method includes the steps of providing a training data set, the training data set encompassing training data of a frequency spectrum including a guard band and/or training data concerning a radio frequency power in the guard band, and feeding the training data set into the artificial intelligence circuit to be trained, which processes the training data set in order to learn a standard frequency spectrum and/or a standard radio frequency power in the guard band, thereby enabling the artificial intelligence circuit, when trained, to determine a deviation from the standard frequency spectrum and/or to determine a deviation from the standard radio frequency power in the guard band. In addition, a monitoring method for identifying an anomaly in a radio frequency spectrum as well as a system for monitoring a radio frequency environment are described.