The Interference Threat

It is well known that several phenomena may affect the quality of the pseudor- ange estimation that is based on the measurement of the propagation time of a signal from a satellite to the user. Any electromagnetic source interacting with the signals is interfering with the process of estimating the propagation time. This book focuses on artificial sources of RFI generated either intentionally or unintentionally by some communication system. The following chapters address such sources of artificial interference and the receiver-based techniques used to detect and mitigate their effects. Note, however, that other kinds of interference might be a threat to GNSS positioning performance. They are discussed in the following subsections, but are not be specifically addressed in this book since their detection and mitigation follows specific approaches.