Design and implementation of GPS ground-based regional integrity monitoring system for China civil aviation

A GPS (global positioning system) GRIMS (ground-based regional integrity monitoring system) was established by considering the particularities of Chinese terrain and the distribution of air traffic flow. A ground-based monitoring network composed of 7 monitoring stations gathered data of all GPS satellites in view and made primitive judgments of GPS satellites' health from all the data gathered. The judgments and important original data were then sent to master station. All RAIM (receiver autonomous integrity monitoring) holes in Chinese airspace, as well as positions of all airplanes of Chinese airlines, were calculated in master station. All airplanes that were considered to be in any RAIM hole would receive a notification message. The time limitation of the whole process from gathering monitoring data to the notification be received was 7 s. GRIMS is used in China civil aviation and improves both safety and efficiency.