Performance of VOR/DME Navigation Aided by Altimeter Data

Positioning with a help of navigational aids data are considered as main backup method is used in civil aviation. Currently, the ground network of navigational aids is minimized to guarantee efficient air navigation service. DME (Distance measuring equipment) and VOR (Very High-Frequency Omnidirectional ranging) are the most useful navigational aids in civil aviation. A pair of co-located VOR/DME is used for airplane navigation and positioning. In the paper, we investigate accuracy of VOR/DME positioning aided by altimeter data. Altimeter data is used for getting horizontal distance from the airplane to DME. However, errors of altimeter degrade overall positioning performance. A Taylor series expansion is used to get analytical formulas for navigation error calculation. Obtained analytical equation transforms the standard deviation of errors from sensor level to errors in the local cartesian reference frame. Obtained formulas have been verified with a help of statistical modeling by Monte Carlo method and compared with results of the simplified formula in form of linear approximation.