DOP can be calculated from the co-variance matrix of the Qx=(AA) qxx qxy qx 4x Why 7. Accuracy Measures The diagonal elements are used for the following doP GDOP=axx+qrr+qn+qu Geometric dilution PDOP=√x+qy+qa Position dilution TDOP Time dilution y Why do we need accuracy measures? What have we learnt? How many accuracy measures are in use! Which parts are important? Chi-square Distribution uracy measures Two-dimensional accuracy measures Three-dimensional accuracy measures6 T 1 X Q (A A) − = DOP can be calculated from the co-variance matrix of the solution.               = tt ZZ Z YY YZ Y XX XY XZ X q q q q q q q q q q Q t t t X Symmetry The diagonal elements are used for the following DOP definitions: GDOP = q XX + q YY + q ZZ + qtt PDOP = q XX + q YY + q ZZ TDOP = qtt Geometric dilution Position dilution Time dilution Why 7. Accuracy Measures Why do we need accuracy measures ? How many accuracy measures are in use! • Qxx, and RMS • Chi-square Distribution • One-dimensional accuracy measures • Two-dimensional accuracy measures • Three-dimensional accuracy measures Summary What have we learnt? Which parts are important?