Military PNT-Systems - A survey

Military PNT systems need to be able to operate while being affected by jamming and spoofing attacks against GNSS receivers. The project Militära PNT-system aims to build knowledge and competence about robust integrated positioning techniques that work in jammed environments. A multi sensor fusion-based system, comprised of a combination of robust GNSS receivers and other sensors, is a prerequisite to achieve desired robustness. This report describes a survey that have been done to increase knowledge of on-going activities around the world, related to the development of encrypted GNSS signals (Galileo Public Regulated Service and GPS M code), modular multi sensor fusion-based PNT systems with open standardized interfaces, and uncertainty estimation and integrity monitoring of sensors and subsystems. Numerous trends were identified within PNT research and development. The use of LEO satellites is a clear trend with increasing advancement. Different aspects of LEO PNT was dealt with at the visited conferences, such as system development (satellite constellations and receivers), performance evaluations and simulation possibilities. This topic should be studied further. Another apparent trend is PNT systems based on open architecture and standardized interfaces, which admits integration of modular subsystems (e.g. sensors and partial integration solutions). This area should be covered by participation in the Nato group SET-309. Participation in conferences with both scientific and industry focus is important to evaluate scientific and technological advances and to gain understanding of how far industry has come with implementation of new technology. Furthermore, participation in conferences is important to make connection with international partners. Participation at the conference arranged by the provider (Spirent UK) of the GNSS simulator used at FOI is important to exchange experiences with other users of the same GNSS simulator model as well as to gain information about plans for future development of the simulator. Development of GNSS should be followed continuously, to gain knowledge of current and future abilities. This is also important for understanding and suggesting relevant combinations of sensors in future navigation systems. Participation in activities such as the test campaign Jammertest in Norway fulfills several purposes. FOI can perform tests that have not been done before and can gain knowledge of how other nations and organizations perform test campaigns with respect to GNSS jamming and spoofing.