Design Practice of Integrity Monitoring Scheme for Ground-based Regional Integrity Monitoring System

R. Xue, J. Zhang, Y. Zhu

Abstract:	Enhancing GNSS to satisfy stringent integrity requirements is key and unsolved issue of GNSS civil aviation applications. A Ground-based Regional Integrity Monitoring System (GRIMS) concept is proposed and implemented by Civil Aviation Administration of China (CAAC), the purpose of which is to support GPS for use as primary navigation system in en-route, terminal and non-precision approach (NPA). The basic idea of GRIMS is a light-weight ground-based GNSS augmentation system, which detects and excludes anomalies in aircraft position solution, i.e. integrity monitoring. GRIMS comprises a network of Ground Reference Stations (GRSs) which incorporate Local Area Augmentation System (LAAS) ground station processes for integrity monitoring, a Integrity Monitoring Center (IMC) which integrates results from all GRSs into a final decision and VHF Data Broadcasting Stations (VDBs) which broadcast integrity information to aircrafts using the same data link and message format as LAAS. Such architecture of GRIMS facilitates integration of LAAS into GRIMS as a monitoring station and extension of GRIMS service to wherever there is a LAAS station. GRIMS and LAAS together can provide seamless augmentation service from en-route down to CAT I precise approach. The interoperability of the two systems greatly reduces overall cost and is more suitable for China than SBAS plus GBAS solution. This paper explicates whole system process of GRIMS, details integrity monitoring scheme, analyzes achievable performance based on simulation and field tests and discusses advantages and possible improvements of GRIMS. Preliminary simulation results indicate that at least 16 monitoring stations are needed to support CAT I operation at most of China civil airports. Simulation is also conducted to demonstrate effectiveness of GRIMS HPL. Deployment of GRIMS is finished by January, 2008. A serial of ground trails are conducted during March to June, 2008 time frame at Beijing, Taiyuan and Xi’an respectively. Both simulation and ground tests approve that GRIMS could satisfy integrity requirements as well as continuity requirements for NPA.
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	1175 - 1180
Cite this article:	Xue, R., Zhang, J., Zhu, Y., "Design Practice of Integrity Monitoring Scheme for Ground-based Regional Integrity Monitoring System," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 1175-1180.
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