Real-time Detection and Localization of GNSS Interference Source

The growing dependence of critical and safety-of-life systems on GNSS makes the ability to rapidly detect and localize the presence of GNSS interference events increasingly important. Ground-based GNSS jammer detection can be used to detect local interference sources. However, this approach is limited by line of sight (LOS) and hence applying it to large areas is costly in both time and money. A complementary technique is to use airborne GNSS receiver data as provided by Automatic Dependent Surveillance—Broadcast (ADS-B). As these receivers are at altitude, their LOSs can cover a wide ground area. The drawback to this method is that ADS-B was not designed for this purpose and the messages contain limited information for the assessment of radio frequency interference (RFI). This paper develops and demonstrates an algorithm for real-time detection and localization of GNSS interference sources using ADS-B. We implement and demonstrate this capability using recorded ADS-B transmissions from known interference events. This paper demonstrates detection of an interference source within few minutes of the onset of transmission and identification of the location within small degrees of error in latitude and longitude. The algorithm does not require prior knowledge about the interference source, it only assumes the source has omnidirectional radiation with continuous transmission. The algorithm generates a probability map for possible locations of the RFI source. This information can then yield the most likely information of the interference source including location and transmitted power. This paper tested the algorithm on a recent interference event that occurred around Denver International Airport (KDEN). This incident resulted in multiple aircraft reporting loss of transponder function and ADS-B issues within 30 NM of KDEN. The tested result showed fast detection and identification of the interference threat.