GPS RECEIVER UTILIZING URA FOR OUTPUTTING 2DRMS, 2DRMS CALCULATING METHOD AND CAR NAVIGATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a GPS receiver capable of adaptably estimating an error in a GPS system, even if reliability of a GPS system is improved or deteriorated, and accurately reflecting that in a 2DRMS.;SOLUTION: The GPS receiver using a Kalman filter for calculating a positioning solution uses an estimated error σH_-Kalman in a horizontal (latitude, longitude) direction calculated from diagonal elements of an error covariance matrix obtained in a calculating process for an estimated value for the Kalman filter for calculating the 2DRMS in accordance with a definition, 2DRMS =2×{(σH_-Kalman)²+(HDOP×σUERE)²}^1/2 and outputting it together with the GPS positioning solution. Herein, σUERE calculates the URA as a 1σvalue for an error based on URA Index contained in a GPS message and σUserSeg as a 1σ value for an error in a user segment out of GPS system segments in accordance with the following definition: σUERE=(URA²+σUserSeg²)^1/2.;COPYRIGHT: (C)2003,JPO