Effect of sampling frequency on GNSS receiver performance

This paper investigates the effect of the sampling frequency on Global Navigation Satellite System (GNSS) receiver performance. Modern digital navigation receivers sample the analog signal at the output of the Intermediate Frequency (IF) filter and implement digital tracking loops. The synchronization of the incoming and local code, fundamental to compute the user's position, is an alignment between two discrete sequences. It is important to recognize that certain relationships between sampling and code rates can result in an accuracy degradation. Although this aspect is understood within a select group within the receiver design community, this paper attempts to present and quantify the impact for a broader audience. Further, commercial vendors have continued to propose such architectures with a sampling frequency that is a multiple of the nominal code rate. This paper demonstrates the impact on the correlation function and pseudorange measurement using variations on the sampling frequency with real data.