The Impact Of Global Navigation System Signal Quality On Signal Receiving Performance

GNSS signal quality determines the gap of receiving performance between designed signal and receiving signal. Different from traditional signal quality assessment, the new signal quality assessment system combines the evaluating factors in time, frequency,correlation and modulation domain. The signal receiving performance is most concerned by users, such as receiver complexity, time to first fix, pseudo range measurement precision. Quantitative relationship between signal receiving performance and signal quality plays an important role in optimizing the signal system design, payload selection and signal transmission channel pre-distortion and so on.In order to research the impact of signal quality on signal receiving performance,firstly, the paper introduces set of the signal quality evaluating factors from time,frequency, modulation, correlation domain and analyzes signal' acquisition, tracking and demodulation performance. Finally, uses correlation as the core to research the impact of the other signal quality indicators on signal receiving performance. The research result shows that correlation loss can not only quantitatively reflect attenuation of the received signal' SNR, but also quantitatively reflect decline of carrier tracking precision and code increment of tracking square loss. The effect of signal waveform distortion on correlation influences by falling edge delay, natural oscillation frequency and damping factor.Reasonable selection of components can reduce the loss, zero crossing slope distortion caused by signal waveform abnormal. The result of modulation factors research shows that signal component phase difference has an obviously influence on carrier tracking.When signal component phase deviation exists, carrier tracking deviation increases along with the signal component power ratio. While signal component amplitude difference may improve the performance of some component, but the loss of signal' comprehensive performance increases because of the signal component phase difference. The carrier leakage will cause the CNR of received signal decreased and slight spectrum distortion can also cause large tracking loop lock deviation.