Evil Waveform Evaluating Method for New GNSS Signals

The waveform characteristics of the navigation signals of Global Navigation Satellite Systems (GNSSs) will be of vital importance for signal quality, which plays an imperative and direct role in achieving high performance of GNSS services. These traditional methods for evaluating evil waveforms mainly deal with the amplitude and width of simple modulated signals such as Phase Shift Keying (PSK) signals. However, no research is done on the influences of waveform asymmetry on tracking errors and ranging errors. Based on the traditional thread models, such as Thread Model A (TMA), Thread Model B (TMB) and Thread Model C (TMC), adopted by International Civil Aviation Organization (ICAO), this paper provides a new extended general thread model suitable for new Binary Offset Carrier (BOC) modulated signals. Then a new evil waveform analysis method, Waveform Rising and Falling Edge Symmetry (WRaFES) Method, is proposed. The effects of WRaFES model are analyzed in detail in terms of time domain, correlation peak and S curve bias. Finally, by taking the B1Cd signal of the first modernized BeiDou navigation satellite System (BDS) experimental satellite named M1-S as an example, tested results of WRaFES model and correlation curves are shown in detail. Results show that the proposed methods could be able to analyze the asymmetry of signal deformation and its impact on ranging performance with high accuracy. The research brings about a new reference for new satellite navigation signal evaluation and signal system optimized design. In addition, it can provide valuable suggestions and technical supports for GNSS users to choose reasonable receivers' correlator spacing.