A new approach for calculating position domain integrity risk for cycle resolution in carrier phase navigation systems

This paper describes a new theoretical approach to quantify the position-domain integrity risk for cycle ambiguity resolution problems. It is typically conservatively assumed that all incorrectly fixed cycle ambiguities cause hazardously large position errors. Although practical and previously used, this conservative assumption can unnecessarily limit navigation availability for applications with stringent requirements for accuracy and integrity. In response, a new method for calculating the fault free integrity risk for carrier phase navigation algorithms is developed. In this method we evaluate the impact of incorrect fixes in the position domain. The method is used to define tight upper bounds on integrity risk in carrier phase navigation systems that demand high availability. A mechanism to implement this method with partially-fixed cycle ambiguity vectors is also derived. The improvement in navigation availability using this method is quantified through covariance analysis simulated over a range of error model parameters.