Integrity Coasting Concept for General Aviation Users of the Ground Based Regional Augmentation System

摘要

It is now widely established that high performance navigation can be achieved by integrating GPS and low-cost inertial Micro-Electro-Mechanical Sensors (MEMS) measurements. However, the high noise and drift rates of these low-cost sensors, and their subsequent inability to coast for sufficient periods during GPS outages has hampered their widespread uptake in general aviation aircraft. The Ground Based Regional Augmentation System (GRAS) will bring high-integrity GPS navigation to General Aviation aircraft, however the potential exists that the GRAS signal could be lost for seconds or minutes at a critical time due to terrain masking or aircraft manoeuvres. A system is therefore needed which can coast through short-period GRAS outages, whilst taking advantage of the superior integrity provided by the GRAS Signal in Space (SiS) when it is available. This paper presents simulation results for a high performance navigation system utilising low-cost MEMS inertial sensors and the GRAS. The system utilises the high accuracy and integrity of GPS navigation when the GRAS SiS is available to calibrate the inertial system parameters, and is then able to coast the navigation solution with high-integrity for short periods if the GRAS signal is not available.