Hardware and Software Implementation for Global Navigation Satellite System Signal Processing by Temporary Accumulation Method to Monitor Radio-navigation Signals

Currently, a scope of satellite radio-navigation applications is more and more extending. Accordingly, there are also increasing requirements for the quality of determining coordinates and time. Therefore, radio-navigation signals monitoring, in particular their waveform control, waveform distortion analysis, is a challenge. However, a power of navigation signals is lower than the noise level, therefore, the special methods and equipment, which provide increasing a signal-to-noise ratio, are necessary to analyze their waveform. Usually, complexes based on the large aperture antennas are used for this purpose. But they have a number of disadvantages, namely high complexity, high price, large size, necessity to guide and track each individual satellite.The paper gives a brief description of the temporary accumulation method (TAM). This method can be applied to signals containing repetitive elements (basic elements). Radio-navigation signals are such signals. TAM allows you to increase the signal-to-noise ratio and evaluate the waveform of signal basic elements by superimposing and averaging the appropriate signal samples. Gain increases with increasing accumulation time.The paper proposes a small-scale breadboard of the software-hardware complex to monitor signals of global navigation satellite systems (GNSS) based on an omnidirectional antenna, a software-defined radio system, and a personal computer. This breadboard allows recording of digital samples of the navigation signals observed, and then their processing by the temporary accumulation method.Presents operation estimates of the proposed breadboard for monitoring GNSS signals. Gives estimates of the GLONASS navigation signal waveforms in the time domain (signal basic elements) and in the frequency domain (energy spectrum). Also based on the use of TAM, estimates the signal power and energy gain. Proves that using the hardware-software complex proposed for radio-navigation signals monitoring is possible.The proposed scheme of the small-scale breadboard for monitoring GNSS signals can be used directly for monitoring and also to test various methods and technologies of navigation signal processing based on the use of information about the waveform of the received signal.