The proposed project will build on the existing capabilities offered by the Spire constellation and develop the tools needed for geolocation signal processing, and to apply these toward the specific task of geolocating GNSS interferences coming from the Earth surface. The project will identify geographic areas for likely detection, develop the detection and geolocation algorithms, plan and execute the data collection campaigns, analyse and summarize the results in a report, and recommend future work to build an operational product.