The Least Squares Method Application for the Global Navigation Satellite Systems Signals Power Measuring

The global navigation satellite systems signals are widely used in the modern society life. One of the most important navigation signals characteristics is their power on the Earth surface. FSUE “VNIIFTRI” carries out regular power measurements using large-aperture dish antenna systems. The structure of navigation signals becomes more complex, code division signals are going to be implemented into GLONASS. Signals spectra with different types of separation could be overlapped, which makes it impossible to measure signal powers directly and separately. For this reason, a new method for measuring the signals power has been proposed and investigated. The method consists of determining the coefficients for normalized spectral power density functions of each signal, which are known a priori, as a result of a linear equations system solution. Modern signal analyzers make it possible to obtain a large amount of measuring data. Therefore, the system turns out to be overdetermined. To solve such a system, the least squares method is used. The individual signal powers are then calculated using the calculated coefficients and the total band power measurements. Results of methodological error evaluating the for various navigation signals carrier frequencies are presented.