Analysis on the Feasibility of Denial of Service of GPS Receivers Based on Hidden Messages

There are two main techniques to disable GPS user receivers from performing navigation fix, either causing interference on transmission route segment or using directional signal radiation on satelliet segment. This paper introduces a new Denial of Service (DoS) technique of GPS receivers that operates on the user segment, which is based on hidden messages from the user segment. The paper focuses on the analysis of the feasibility and covertness of using a large number of reserved bits in GPS L1C Nav navigation message to carry and transmit hidden messages, as well as of the feasibility of using expanded data types of GPS L2C CNav navigation messages to transmit hidden messages. Based on the reserved bits in GPS L1C Nav, two formats of hidden messages are designed, with mainframe and superframe as basic carrying units for transmission. Besides, the paper presents four approximate representations of DoS target areas, and probes into the position matching in DoS of GPS receivers. The research in this paper shows that it is feasible to realize DoS of GPS receivers based on hidden messages and hidden messages are provided with high convertness by transmission channels.