Integrated GPS/Inertial Fault Detection Availability

Abstract

Different techniques have been proposed for combining GPS and inertial sensor information, and recent published findings seem to indicate that primary-means integrity availability is achievable with standard 2 nmi/h (95 percent) inertial sensor performance. This paper investigates and quantifies the different inertial effects that contribute to enhanced integrity of the integrated GPS/inertial system, such as coasting or Schuler feedback. A Kalman filter-based integration scheme that preserves the integrity information in an optimal fashion is presented and used to quantify integrity performance. This paper also proposes an approximate model, incorporating the main inertial effects contributing to integrity, that can be used to calculate the achievable horizontal protection level (HPL) at any geographical location and time. This model is used to estimate the availability of fault detection for an integrated GPS/inertial system. In addition, the paper compares the availability of fault detection for the GPS/inertial system with that for other augmentations to provide trade-off information.