Position accuracy analysis in terrain-aided navigation systems

The influence of information support uncertainties and operating conditions on corrections provided by the recurrent-research algorithm of the terrain-aided navigation system has been studied. As is known, uncertainties of the position coordinates depends on many factors, including the inertial system errors, reference information errors, a measurer of the geophysical field errors, the information value of the terrain area, etc. The results of the analysis show that the uncertainty caused by the error in speed rises with an increase of the number of the geophysical field measurements. The component caused by uncertainties of information support, on the contrary, decreases. Also, in this article expressions were obtained that can be used when planning the flight route and choosing terrain areas for performing correction. In particular, an equation has been synthesized that establishes a relationship between the standard deviation of the heights gradient, standard deviation of the heights, and the height field correlation radius. An expression has also been formed that allows us to calculate the optimal measurements number necessary for correction, under the conditions of the measurers errors and the movement trajectory.