Effects of Continuous Wave Interference on Pseudorandom Code Tracking Error under Large Error Conditions

Continuous Wave Interference (CWI) can induce large code tracking error, and the tracking error analysis based on small error conditions becomes invalid. Under large error conditions, since code loop discriminator is no longer working in the linear region, the second-order Taylor series expansion of discriminator output is introduced instead of linear approximation, and analytical expressions of the tracking error in the presence of CWI are derived. Numerical analysis and simulation results are presented to evaluate the code tracking error with different initial phases，interference frequencies and interference-to-signal power ratio (ISR). The experimental results show that, when the code tracking error induced by CWI is large, the prediction accuracy of theoretical analysis based on linearized discriminator decreases noticeable, while the new theoretical expressions based on second-order Taylor series expansion provide accurate predictions of code tracking errors under large error conditions. If the code tracking error is smaller than 0.34 chip, the theoretical prediction error is no more than 20%.