Interference Localisation within the GNSS Environmental Monitoring System (GEMS)

Due to their low-power levels, GPS signals are very susceptible to interference from either intentional or unintentional sources. This vulnerability is further aggravated by the increased reliance of the civilian infrastructure on GPS for time synchronization. This brings about the pressing need for detection and localisation of the interferers in real-time to prevent disturbance to everyday operation of this infrastructure. This paper details the upgrades to one such system, GNSS Environmental Monitoring System (GEMS) which consists of a number of sensor stations connected to a central processing unit, to achieve real-time interference localisation. The paper describes the GEMS environment and details and compares performance of various time and frequency domain Time Difference of Arrival (TDOA) estimation approaches.