Demonstration of a Multi-Layer Spoofing Detection Implemented in a High Precision GNSS Receiver

Civilian applications including vehicular navigation, electrical power grids and digital communication networks are relying on GNSS-based position and timing services and motivation has increased to disrupt these systems and endanger safety of life and critical applications. GNSS signals are susceptible to jamming and spoofing attacks due to being weak near the earth's surface. Herein, realistic spoofing scenarios and their features will be characterized. This characterization is based on spoofing/authentic relative signal power, how synchronous the spoofing signals are to the authentic ones and the availability of both spoofing and authentic signals. A variety of detection methods are defined, using metrics derived at different layers of a GNSS receiver with a single antenna input. An on-board spoofing detection unit was implemented on NovAtel's OEM7 family of receivers. This unit collects different metrics from the GNSS signal processing chain and provides a real-time indication if the receiver is under spoofing attack. The probability of false detection during jamming or multipath conditions is given special consideration, since a false declaration of the presence of a spoofing attack could lead to incorrect, unnecessary or even dangerous reactions from the user or spoofing mitigation implementations. However, if spoofing signals are present, the user (and the receiver) must be aware of these to choose an appropriate course of action. Test results are presented using several spoofing scenarios based on GNSS hardware simulator, repeaters and software defined radios in conditions ranging from stationary to kinematic, with low and high levels of multipath.