Navigation Using LINK-16 GPS-INS Integration

The LINK-16 standard for military anti-jam digital communications provides Anti-Jam (AJ) communications using Frequency Hop and Pseudo Noise (PN) spreading techniques. As a result, there are accurate time-of-arrival (TOA) measurements between the transmitting terminals. This paper describes the design and development of an integrated navigation filter that is capable of exploiting LINK-16 TOA measurements, along with GPS/IMU measurements, to provide robust navigation in GPSdenied conditions. Results are presented that show the advantage that a LINK-16 aided navigation system has over standard GPS/INS navigation in a hostile GPS environment. INTRODUCTION The LINK-16 standard for military anti-jam digital communications has been implemented in the Joint Tactical Information Distribution System (JTIDS) terminals, the F-15 Fighter Data Link (FDL) and the Multifunctional Information Distribution System (MIDS) terminals. These systems provide Anti-Jam (AJ) communications using Frequency Hop and Pseudo Noise (PN) spreading techniques. As a result, there are accurate time-of-arrival (TOA) measurements between the transmitting terminals. The Global Positioning System (GPS) uses satellites transmitting PN spread signals to measure TOA from the transmitting satellites to the receiving GPS terminals. NAVSYS has developed an integrated navigation filter capability, the InterNav product, which optimally integrates GPS, Inertial Measurement Unit (IMU) and other sensor data. In this paper we describe an extension to this filter design where JTIDS TOA information, available from ViaSat’s MIDS terminals, could be applied for use in providing a robust navigation solution, albeit at lower accuracies, under GPS-denied conditions.