Operational Adaptation of Digital Filter Parameters when Changing the Discrete Time Step in the Problems of Forming the Control of Unmanned Vehicles Using Satellite Measurements

Moscow Aviation Institute (National Research University), Moscow, Russia

^* Corresponding author: belonogov@bk.ru

Abstract

For the tasks of controlling unmanned vehicles using external information signals, in some cases, a change in the time parameters T₀ of periodic data receipt is typical. Such systems, the processing of incoming information in order to form digital control is implemented by digital filters (DF), based on discrete samples x[k] of some continuous signal x(t) at quantization times tk=k*T₀ Here T₀[seconds]- the period of discreteness in time, k=0,1,2,.. an integer variable, essentially a time counter. The properties of the filter are uniquely specified by its specific mathematical model - the discrete impulse transient function [1,3] of the filter (DITF), which characterizes the filter operation at a specific step T₀= 1/f₀, where f₀ (hertz) is the frequency. When the time intervals T₀ of data arrival change, for example, due to a change in the transmission conditions in the radio channel, or due to a change in the location of the satellite constellation, the filter properties will change during operation [2], and if T₀ changes significantly, such filtering can lead to unsatisfactory results. In this paper, for the parameters of the digital filter, the adaptation problem is posed and solved, which ensures the invariance of the nature DITF, in contrast to the stabilization of the frequency properties of the digital filter, studied in [4]. To rebuild the numerical parameters of the filter, an algorithm is proposed that uses information about the time intervals obtained by direct measurement. At the stage of filter development, a special recalculation matrix is formed and when the filter is running in real time, the digital filter parameters are recalculated. For a model example, the calculation results are presented, which show good tuning accuracy, stable filter characteristics, as well as the simplicity of the required calculations on board with a significant change in time intervals.