Modified Direct Positioning Method in Satellite Geolocation

The paper presents features of direct positioning method application in satellite geolocation for radio source with unknown signal waveform. This method is used in terrestrial radio monitoring systems along with the widespread two-step method. The paper proposes a modification of the satellite geolocation direct method. The modified direct method reduces computational costs for implementation of signal processing on the satellite geolocation ground station and increases the radio source positioning accuracy. The accuracy benefit of the modified direct method increases when attenuation increases in the channels of adjacent satellites of the satellite geolocation system and signal to noise ratio decreases. The paper analyzes the efficiency of the direct method and its modification with an arbitrary ratio between the frequency band of the radio source signal and the analyzed frequency band of the satellite geolocation ground station. This analysis showed the advantage of the modified direct method in a wide range of analysis bandwidths, signal-to-noise ratios, and attenuation in the adjacent channels.