GPS Integrity Monitoring Integration in the Kaman SH-2G(A) Super Seasprite Helicopter for the Royal Australian Navy

GPS has, in a relatively short period of time, become so commonplace that its availability and accuracy are often unquestioned. For many applications, the consequences of loss of availability or degradation of accuracy are insignificant or even unnoticed to the user. For aviation applications, however, with increasing availability of GPS-equipped aircraft and GPS procedures (departure, en-route and terminal), the ability to determine GPS availability in the flight planning stage, and real-time in-flight monitoring the integrity of its navigation solution, is becoming increasingly critical. Two distinct methods of assuring GPS integrity have evolved as the use of GPS has progressed. One approach, Receiver Autonomous Integrity Monitoring (RAIM), is based entirely on received signals from the GPS satellites and, therefore, provides the user-platform with an “autonomous” integrity monitoring capability. The other approach, known as GPS Integrity Channel (GIC), relies a network of ground monitoring stations dedicated to GPS integrity monitoring. Of these two approaches (GIC and RAIM) for monitoring the integrity of the GPS navigation solution, RAIM is the only method that has gained regulatory recognition as evidenced by such documents as TSO C129A2 (Airborne Supplemental Navigation Equipment Using The Global Positioning System (GPS)) and RTCA DO-2083 (Minimum Operational Performance Standards for Airborne Supplemental Navigation Equipment Using Global Positioning System (GPS)). This paper addresses the application of RAIM to the SH-2G(A) variant of the Kaman Super Sea Sprite as part of its fully integrated tactical avionics system including; • LN-100G with embedded GPS • Integration of RAIM with the Integrated Tactical Avionics System (ITAS) • Human-Machine Interface (HMI) design and • Demonstration of RAIM integration