Analysis of the Effect of Carrier’s Spurious Signals on the Code-Tracking Accuracy

Abstract

Carrier’s spurious signals are the unideal frequency fractions containing in a single-frequency carrier signal. Spur-to-carrier rejection is a kernel index to characterize the unideal quality of a carrier signal. This paper presents a method for analyzing the effect of carrier’s spurious signals on the code-tracking error. First, the time-domain and frequency-domain expressions of the interference signals caused by carrier’s spurious signals are deduced strictly, based on code-tracking loops employing coherent early-late processing (CELP) and noncoherent early-late processing (NELP) respectively. In order to describe the degradation of code-tracking accuracy caused by carrier’s spurious signals, and to separate it from the total code-tracking error, the upper bounds of additional code-tracking error (UBACE) for CELP and NELP are defined through theoretical deduction. After that three scenes on different kinds of spur-to-carrier rejections are set up, and the UBACEs for CELP and NELP are simulated. Finally the influences of the corresponding parameters on the UBACEs for CELP and NELP are analyzed by using the theoretical formulas and simulation results. The method herein can be applied to evaluate the quality of generated signals, as well as to determine the index demand of the emitter’s spur-to-carrier rejection.